Question:
I'm trying to build a headrest for my Sayl office chair. For that, I'm designing a 3d-printed part that's going to fit on one of the existing rods of the chair.

Check out this picture:

How would you go about in getting the exact measurements of that white rod? I tried a caliper, and I'm able to get the width and depth, and I can just assume that the rod's profile is a perfect ellipse, which is probably a close estimate. But say that I want to get a more precise measurement. Is there any technique to do that?

Answer:
You could pull it apart and have it 3d scanned if you want to know the exact dimensions. There are companies that can do that for you at a certain price. Our company has used such services in scanning various parts before we obtained our own laser scanning device.
The question is whether you want exactly the same (dimension wise) part (maybe you do for ecstatic reasons) while a part that is a little more beefier would work also.
Edit:
Although tagged with 3D scanning, the OP did not mention whether he would be able to disassemble the part. 3D scanning is an option when taken apart. Another solution has been posted since.


Question:
I want to print a structure that I can embed in a resin and later dissolve. I know that some fancy 3D printing systems have raft materials etc., that can be printed and later removed easily.

Can any one suggest a 3D printing material that can be dissolved in say water or another readily available solvent?

Answer:
ABS dissolves in acetone. Indeed actone can be used to clean up 3D prints, see
What's smoother? Acetone treated PLA or ABS
. PLA maybe not somuch as ABS, see the same post.
PLA dissolves in any chlorinated or fluorinated solvent, such as THF or Chloroform - both of which are significantly more hazardous than acetone.
Hence, as always
take care
when using solvents, see
Safety precautions when using acetone
Also, as filaments are often not pure ABS or PLA, due to additives and dyes, etc., then the solvent may not dissolve the 3D printed part
completely
, and you may be left with a deformed, rubbery residue.


Question:
Ok so I am trying to print a new fusion 360 file that I converted into an STL and then into gcode using cura and I got the gcode loaded onto the SD card and mounted into my Monoprice 3D printer, Maker Select 3D Printer v2, and tried to do a print. Now here is the strange part. When I choose "print file" and then select a gcode to print it takes me back to the main screen and from there the 3D printers screen displays "Printing...0%" for a few seconds. After this it just goes back to displaying "Stepper Disabled." And if it is not stepper disabled it is just a blank screen. I tried to mount and print multiple gcodes just to make sure that it was not the softwares fault and low and behold I was running into the same issue.

Now before using today all of the gcode was printing just fine, however for some reason today it decided to give me this issue.

Answer:
ABS dissolves in acetone. Indeed actone can be used to clean up 3D prints, see
What's smoother? Acetone treated PLA or ABS
. PLA maybe not somuch as ABS, see the same post.
PLA dissolves in any chlorinated or fluorinated solvent, such as THF or Chloroform - both of which are significantly more hazardous than acetone.
Hence, as always
take care
when using solvents, see
Safety precautions when using acetone
Also, as filaments are often not pure ABS or PLA, due to additives and dyes, etc., then the solvent may not dissolve the 3D printed part
completely
, and you may be left with a deformed, rubbery residue.


Question:
I am using 2 extruders. Is it possible to use them both at the same time.
Now I can use one at a time but not both at the same time.
Is there a gcode that supports this action?

Answer:
To print with 2 extruders simultaneously you need a firmware that supports that. Luckily, there is a firmware called Sailfish that is able to do that. The feature you are looking for is called
```
Ditto
```
printing.
Sailfish firmware is found
here


Question: I recently saw this video of super-swellable polymer and felt inspired. Printing a swellable structure would be sort of interesting. However, sodium polyacrylate isn't a printable material. Does anyone know of a material that is? Preferably, swelling activated by water.

Answer:
To print with 2 extruders simultaneously you need a firmware that supports that. Luckily, there is a firmware called Sailfish that is able to do that. The feature you are looking for is called
```
Ditto
```
printing.
Sailfish firmware is found
here


Question:
I need to add some simple image renders of STL files to a document.  I currently open the STL files in Preview or one of the slicers and grab a screen shot.

Is there an easier or automatic way to generate PNG images from STL files on a Mac?

Answer:
Typically you would install a (free) 3D model program as Fusion 360, FreeCAD, or many more options to choose from. Once installed, import the STL file and use menu options to export a picture of your STL.
Alternatively, if you have some programming skills, you could
import the STL file
in OpenSCAD and render and export a picture from there. Simply create an OpenSCAD file with the code line below and it will import your
```
example.stl
```
.
```
```
import("example.stl", convexity=10);
```
```
Through the menu you can then export the view to an image. Note that you can do that also from the
command line
as shown by the OP's own answer (nice example of command line usage of OpenSCAD).
These are not the only options, there are many more. E.g.
this
is a nice example. It also describes how Thingiverse.com does STL to web image.


Question:
If I set temperature say 220 °C, printer heats up to it and it only varies +/- 0.5 °C under non operating condition. But if I start a print, there's a shift of +/- 15 °C.

I've already auto tuned PID parameters and when I run M503, the printer shows the updated PID values.

What could be the reason?

Electronics details:

Firmware used:  Marlin

Controller board: Printrboard rev D

Answer:
There could be a number of reasons for that behaviour:
Please check following items:
part blower/fan cools down the nozzle - stop the fan
material is extruded at high speed and takes the heat
loose thermistor (when the move occurs as it moves a bit internally)
the power supply unit voltage varies - so temperature reading varies as well - measure voltage and see if there are significant drops
nozzle heater and thermistor cables can be loose as well (check screw terminals)
bed heater connection cables having not a good connection (check screw terminals)


Question: In cura one of the options under "build plate adhesion" is "skirt", which seems to simply print a loop around, but not touching, my print. How is this supposed to help my prints stick to the bed?

Answer:
These skirts they don't contribute at all to help your product adhere better to the build plate other than priming your nozzle so that it is ready to lay down filament for your product.
A skirt
does
give a good indication of the adhesion prior to printing your product, if the skirt does not adhere, maybe it is a good time to stop the print and re-slice with different options or fix the bed level.


Question:
2 days into a 5-day build, I came home from work and found the build ruined because the build plate had slipped.

I'm using a Raise 3D N2 Plus printer, with the standard glass build plate that comes with it, attached via 4 clips: two stationary ones at the back, and two standard binder clips at the front, which shipped with the printer, which hold the glass build plate plate to the heated surface beneath.

The left-side clip had come off of the heated surface, remaining clipped to the top and bottom of the glass plate, and the whole thing slipped an inch or so.  I immediately canceled the build, and I can start another one, but before I do I'd like to know how this happened and what I can do to prevent it from happening again.

What typically causes the plate clips to come free?  Is there anything I can do about it?  Will adding more clips around the edges help?  I'd really prefer not to ruin more builds if I can help it...

Answer:
Your nozzle may have caught up with the print somehow pushing the binder clip off by moving the glass slate.
Apparently this is a more
common
problem. Try adding more binder clips, this has been reported to help preventing shifting.
Maybe with some ingenuity you could develop your own fastening system depending on the bed. Alternatively, you could make the underside of the glass a little sticky so that it does not move easily (a little PVA based glue maybe or hairspray, I've done that with my mouse mat with 3DLAC :) which is now not slipping from the desk).


Question:
I changed the filament (PLA) in my Wanhao Duplicator I3+. I ended the first try to print when I saw that the 'lines' were too thin. I re-sliced with a higher temperature (195°C instead of 190°C). Now the print started without a problem but after about 25% no more filament came out of the extruder. What can be the reason and how can I resolve it?

The filament is from Vertex, grey. The object that I use to test is a 20 mm hollow cube from Thingiverse that I have used for the previous filament too.

I am not sure that this is a clogging problem since the print starts with no problems. It just stopped after 25%. When I started another print I was able to finish by increasing the temperature.

Answer:
My slicer (Cura-lulzbot) has a setting for initial printing temp, and then printing temp after the first few layers.  Is it possible that your temp is initially OK, but then drops too low?  Does your printer have a readout that shows the current temp?  Is the temp still OK when it stops?
It sounds like you are printing a sample cube, so I assume not too large.  Could you simulate this by just directly command your printer to extrude 500 mm of filament, or longer?  Then see if it clogs.  That would tell you if it was a physical problem with your printer instead of some change specified by the G-code for a sliced print.


Question:
Just one quick question about the filament.

Can I leave the filament in the extruder for a prolonged period of time while the printer is off?

Answer:
Most filaments you can leave in the extruder indefinitely without any ill effects.
There are some filaments that need to be stored away from moisture, particularly Nylon, because they absorb moisture from the air and don't print well if they contain a lot of absorbed moisture. However, this isn't an inherent issue with having the filaments in the extruder (if you had some setup that protected the filament from moisture while in the extruder, that would be fine as well - but in most cases it is more practical to store such filament in an airtight box).
Most commodity filaments (ABS/PLA/PETG) don't suffer from this as much (PLA supposedly also absorbs moisture but I haven't noticed this to be a problem, perhaps it depends on the conditions of the room in which your printer is kept) so they're fine to leave in the extruder.


Question:
I cannot get my extruder to work on my Creality Ender-4 printer. I have heated the nozzle but the extruder does not move.

I tested the motor and cable on another system and they work just fine.

Could it be the board or what could it be?

Answer:
Most filaments you can leave in the extruder indefinitely without any ill effects.
There are some filaments that need to be stored away from moisture, particularly Nylon, because they absorb moisture from the air and don't print well if they contain a lot of absorbed moisture. However, this isn't an inherent issue with having the filaments in the extruder (if you had some setup that protected the filament from moisture while in the extruder, that would be fine as well - but in most cases it is more practical to store such filament in an airtight box).
Most commodity filaments (ABS/PLA/PETG) don't suffer from this as much (PLA supposedly also absorbs moisture but I haven't noticed this to be a problem, perhaps it depends on the conditions of the room in which your printer is kept) so they're fine to leave in the extruder.


Question:
If I'm working with standard PLA, and I want to print a box that I can stand on without any risk of it breaking, is there any good way to calculate the appropriate print settings?

I know that structural strength comes from the infill.  Knowing this, and knowing the dimensions of the box, the weight of my body, the surface area of my shoes, and the material I'm working with, is there any good way to determine the minimum infill percentage I'd want to use in order to safely bear my weight?

Answer:
Strictly speaking, it is difficult to do calculations on these materials, but not impossible (I've heard about a few commercial analysis tools that do that). The FDM process (Fused Deposition Modeling) creates a product based of fused slices of material causing an anisotropic material (this means that the properties of the material are different in different dimensions). Basically, your product will be quite strong and similar in the X and Y directions, but fragile in the Z direction (layering direction). You can imagine that every layer may be a seed for cracks to grow when you're pulling at the part.
When applying a compression load on a product like in your example, the walls need to be strong enough to hold the pressure (not all of the load as, based on the type of infill, the infill also can/should take part of the load!) and need to be of sufficiently high percentage, not only to take part of the load, but also support the walls to prevent buckling. I remember that stress calculations for buckling are difficult and require FEA (Finite Element Analysis) for more complex objects other than bars or beams.
I think it is difficult to determine or calculate the infill percentage based on the compression load beforehand as you do not know the exact material properties and the buckling behavior. You do know that a 100% infill will give you enough strength and support, you could try to print at a lower infill, e.g. 75%, and test if that works for you.


Question:
My Zortrax M200 has a skipping extruder motor, I’ve checked the seating of all connections and 3 different (electronic ribbon) cables and still can’t fix the issue. The gear is clean and have tried fresh filament.

Does anyone have any possible thoughts on why this happens?

The extruded motor will move in the desired direction and then skip back.

Loading the filament is fine. Tried new nozzles, blockages checked, etc.

Answer:
Check the pins on the motor. Are they bent? If yes - straighten them out with a screw driver.
This could be a stepper driver problem. If it is then bad luck. Zortrax hard solders their stepper drivers onto their control board (this sucks and is a pure monetization related move by them).
This results in you having to get a whole new set of connector cables and or new control boards every time something goes wrong.
Ask for a control board replacement with new connector cables, if your machine is still under warranty it should be free of charge.
Switch to different or cheaper machines like Wanhaos or Ultimakers if you want the same ease of use and cheap part replacement.


Question:
I have a question about Slic3r software.

I would like to subtract two parts. For example, I have an STL model, when I right click on the part, I can select Settings..., and in the Settings window, I can select modifier and I can select slab.with selecting proper thickness. Now we have two parts where one of them is inside of another. My problem is subtracting those two parts.

How can I subtract this part from another?

Answer:
Given my limited familiarity with all the CAD tools that exist, I would fall back to something that I know does binary operations on volumes -- openScad.
One can create two objects, one from each of the two STL files, and subtract one from the other.  One can also compute intersections, unions, and other operations.
There are probably other programs that also do this, but openScad allows for doing in programmatically, so that once you have it right, you can update the objects without needing to redo the finicky part of the operations.
slic3r may do this, but I haven't seen such features in my multi-year use of slic3r for slicing.
When in doubt, IMO it is better to script something.  It is virtually never that I do something only once, especially in 3D printing where rapid prototype leads to rapid change and improvement.


Question:
I finished the mount of my Anet A8, tested everything and apparently it was ok. I installed the driver that came with it, CH341SER_MAC, turned on the printer, connect USB cable, but nothing happened.

In Cura, I tried to add a printer many times and this message always appears

The printer isn't connected.

In OSX, I discover in System Information, an USB2.0-Serial, that I think can be the printer.  Is it a printer driver problem? Is it the Cura setting? I'm completely lost...

Answer:
There are a lot of problems with the CH340 chipset drivers to be found on 3D SE and various forums on the internet. To use this cheap CH340 chip that is used by a number of Arduino compatible (clone) boards to provide USB connectivity (a USB bus converter chip that converts USB bus signals to serial interface) you need to install a correct working driver.
For Mac OS X you can try to download a working version for the OS system you are using. You can try to use
this driver installer
or
this driver installer
. Both reported to work with Mac OS.
Edit
: If you are using OSX El Capitan, please read
this
. To  get the CH340 drivers to work you need to use the tool
csrutil
.
Reboot and press CMD+R immediately after hearing the startup sound to boot to Recovery Mode
Open Terminal
Execute the following command:
```
csrutil enable --without kext
```
Reboot
More information is found
here
!


Question:
I just re-ran all basic calibration steps from the Original Prusa i3 MK2 Manual.

Now, when doing the first layer calibration, lines that are running in positive X direction are ok, while those running in negative X direction are severely squished.

(The "waviness" of my print bed is an artifact of the camera lens distortion of my smartphone)

I already did Bed level correction, so each line is exactly the same width over its entire distance and tried to raise the live-adjust Z, but that leads to the thin lines not adhering at all. My printer is 100% stock, I modified nothing about it.

What can I do to troubleshoot this further?

Answer:
No FDM print at all.
The problem of your design will not be the materials, but a basic property of FDM printing: FDM Printers do create a structure by placing a long string of filament next to itself and ontop of itself, creating tons of boudaries.
These boundaries between the layers are the weak points for this application: Even if the material like ABS could withstand the blow handled with such a club, the print will break at its weakest point - which in this case is any layer boundary. This is amplyfied by the basic design we have here: The elongated shape will serve as a lever on each of the weak boundries, until one gives way and results in catastrophic failure and a flying clubhead.
Non-FDM for the rescue.
To counteract this, you need to use a different method than FDM printing to get a more homogenous material than the bound deposited filament. Such methods could be for example SLA (Stereolithography) or SLS (Selective Laser Sintering). Both could easily offer even tiny details.
SLS uses Nylon or metal powders, sometimes even ceramics - Tungstencarbide for example.
SLA/Resin
Using a Resin printer using the SLA methods results in an object almost as homogenous as an injecion molded object. Proper aftercare and curing is required to get the best results. Also, Resin prints usually age under UV light, which can negatively impact lifetime. SLA printers are expensive (for home printers), print shops that offer them relatively rare and costly (in comparison to FDM) but usually offer superb resolution and almost perfect smoothness. A lot of the exact material properties is resin and aftercare dependant.
A way around the aging could be that the results of an SLA print could be used to create green-sand molds countless times, which can be used for casting metal or even some thermoplastics. Remember though, that cooling metal shrinks.
SLS Nylon
Nylon would be a medium rigid, light solution, but it ages and has a quite rough surface. It does offer some flex, almost perfect for this application. While most SLS machines for nylon are commercial to industrial, print technology of this kind is widespread enough to make them somewhat affordable (for an industrial printer) and printshops for these relatively common, prints are not cheap but well priced.
DMLS / SLM
Direct Metal Laser Sintering and Selective Laser Melting - an evolution of SLS - allows to create structures from various metals by sintering/melting powders of metal at the right spot to gain shape. The benefit would be, that you get a part that could withstand much more destructive testing than your bottle used as a clubhead - you get a workpiece of solid metal (Steel, aluminium, Titanium and a lot others are available) after all that has the same properties as a cast item. The big downside is, that only few companies currently delve into DMLS, among them the former patent holder of many of the FDM printing patents,
Stratasys
. This means, that a machine for this is industrial rated and priced, and that print suppliers charge accordingly.


Question:
When using Slic3r I noticed that Slice now and Export G-Code do different things. While Slice now is nice, it does not show any tool paths etc.

Is there an actual way to generate and visualize the G-code in Slic3r without saving the exported G-Code first? When aligning seams etc., it is quite annoying to always save the file to see a difference because Slice now seems to make little difference.

Answer:
After you use the Slice Now button (and the slicing progress bar shows completed), select the preview tab. To the right of the window you will see a pair of vertical sliders. Each slider changes the start and finish locations for the filament layers.
You can slide the left one to the bottom, which will "empty" the virtual print bed. Each movement upward will display a succeeding layer, showing the placement of the filament. This ostensibly will present to you alignment information as well as unexpected holes or other failure points.
I don't know of any slicer that lacks a preview. That doesn't mean one does not exist, but why would such a useful feature be omitted?


Question:
My G29 command reports

+0.178 +0.281 +0.830
-0.614 -0.012 +0.371
-1.208 -0.849 -0.351

So should I tighten up the screw of the bed, close to 0,0 position or loosen it?

I have a feeling that when I loosen it, it gets away from zero and I expect the opposite to happen.

For bed leveling i use a capacitive probe and after playing around with the screws here is the result

+0.406 +0.127 +0.411
-0.161 -0.007 -0.041
-0.572 -0.652 -0.668

Finally the leveling process was found here
But the question remains. The value -0.572 corresponds close to 0,0 ?

Answer:
After you use the Slice Now button (and the slicing progress bar shows completed), select the preview tab. To the right of the window you will see a pair of vertical sliders. Each slider changes the start and finish locations for the filament layers.
You can slide the left one to the bottom, which will "empty" the virtual print bed. Each movement upward will display a succeeding layer, showing the placement of the filament. This ostensibly will present to you alignment information as well as unexpected holes or other failure points.
I don't know of any slicer that lacks a preview. That doesn't mean one does not exist, but why would such a useful feature be omitted?


Question:
I have an incoming project and the only 3D printer available to me is the TronXY X1.

So the question is: Can it handle at least four days of continuous load or should I search for an alternate solution?

I don't want to damage (my only) 3D printer for this project.

Answer:
I know that this is a bit
wishy-washy
but some can, some can't.
The TronXY has a bit of an issue with the power supply to start with. The
power brick
is a (
reportedly
) bit suspect, for long jobs, see
my answer
to the question,
Ramps 1.4 with a power brick
.
It could be worth upgrading the power supply to a higher current rated PSU (20 A - 35 A), with an aluminium enclosure, i.e. those PSUs which are marketed as LED power supplies, such as this,
Tronxy 3D printer accessoires power supply 240W AC110/220V DC 12V 20A for 3D print DIY kit part
on AliExpress.
Then you can add your heatbed (that you refer to in your other question), without worrying.
It all depends on how critical your 24/7 project is. Is it a serious production run or just a hobby-like project that is a bit of a fun endurance test? How important is it that the print run goes without a hitch? Would a power supply failure mid-print be catastrophic or easily shrugged off? Would the delay incurred by trying to find a replacement power brick actually matter that much?
A simple analogy would be driving from Germany to Mauritania across the Western Sahara, with some serious, and urgent medical supplies. You could either either buy a well maintained, and carefully run in, Mercedes, which will most likely last the entire journey and then some,
or
you could buy a clapped out old Lada, with 500000 km on the clock, with the vain hope of getting there. The Mercedes would seem to be the better option.
However, if you are delivering a
Dundee cake
for an Aunt, which is neither time critical nor particularly important and you aren't even sure that your Aunt will be at home when you get there, then maybe the Lada will suffice.
Into which category does your 24/7 print project fall in? It sounds like the former.
Apart from the power supply, i.e. w.r.t. the stepper motors and hotend, unfortunately, I don't know the answer and can not answer your question.


Question:
Why does this happen (circled in red), and how can I fix it? It is making my prints come out horrible.

Not shown in the picture, but the option "Coasting" was Enabled:

Coasting Volume 0.064 mm3

Minimum Volume Before Coasting: 0.8

Coasting Speed 90%

Answer:
I have had a similar thing happen when slicing a large piece that has - in real life - walls of about 2 cm. By scaling it down to 1.5%, this become less than the wall thickness, and the wall was simply omitted by CURA.
In my experience, a model showing gaps
can
have in these locations a thickness less than 1 wall.


Question:
My first printer is Delta style Kossel clone and I have bad luck with Print In Place (PIP) models, especially with hinges. I suspect that my printer just can't achieve low enough tolerances to make the hinges work.

Are there any tricks I can employ to get better prints for PIP models?

Answer:
Delta printers are considered to be able to be accurate printers cause of the limited weight in the head (using Bowden extruder setup). The positioning can be very accurate (limited weight, limited overshooting) and because of the limited amount of weight, the print speed can be increased.
An
interesting paper
has been written on a comparative study between a Cartesian and a Delta machine. The paper concludes that the Delta style printer produces "a better surface finish". However, I'm a bit skeptical as the images of the Cartesian printed part they have printed are of far less quality I can produce with 2 of my printers. Fact is that Delta machines have no Z-wobble (also called
banding
) that is a common problem with Prusa i3 style printers for instance.


Question:
I am slicing with Cura and Slic3r and one important thing that I recently took my attention is that cura positions head in start point of the new layer and then lifts the nozzle. That caused my few printouts to fall as they collided with the nozzle.

Slic3r behavior is different: it raises the nozzle in last printed point and then moves to a new layer starting point (which for me is more obvious)

Is there a way to instruct Cura to lift nozzle before it goes to the starting point of a new layer? excluding Z-hops.

Answer:
To lift the head to prevent the nozzle to tip over your print you could use an option called
```
Z hop
```
in Cura. Just enter `hop' in the search box on the right side to make those options magically appear (in a recent version of Cura, e.g. version 3.x.x).
Other than
```
Z hop
```
there is no default action, or series of commands, per layer to be specified before the start of the layer. There are 2 other ways to circumvent this:
The first is saving you G-code to file and open the file in an advanced text editor (e.g. Notepad++). With a (recorded) macro you can find the words
```
;LAYER:
```
, which are inserted by Cura before each layer starts, and insert a pre-copied list of commands that set the movement in relative mode, move Z up 2 mm, set into absolute mode again. When the next layer starts the extruder goes to the layer start from a 2 mm rise.
Write a plugin for Cura to post-process (
```
C:\Program Files\Ultimaker Cura x.x\plugins\PostProcessingPlugin\scripts
```
) the G-code file to inject the code to Z hop before the start of every layer, or a plugin that adds a new option and/or category to the slicer settings sidebar of the GUI.


Question:
I am getting a 24 V based Ender 3. From the factory, it has an aluminium bed. So I also put this LJ12 A3-4-Z/BX Inductive NPN NO 4 mm with 6-36 V operation current into the box together with a few other spare parts. Now, as I read up on these things something dawns on me: The normal input and output voltage of a simple switch is 5 V, as sensors are ran on 5 V on most boards (and in digital logics). The sensors run on 6 V plus though.

I do not want to fry my machine by putting in 24 V into the sensor input: What do I have to do (besides making a mount)?

Answer:
The inductive sensors work better when you apply a higher voltage than 5 V. Usually they are rated for 6-36 V, but please do check.
To prevent frying your board when connecting the sensor to (12 or) 24 Volts you could optically isolate the 5 V and the (12 or) 24 V circuit with an OptoCoupler module:
Image of an optocoupler module
This module uses an optical switch based on the output of the sensor and should be correctly connected:
Image of connecting an optocoupler module to the sensor and to the board
Please note that the image uses a capacitive sensor rather than a inductive sensor, both are connected similarly
Note that there are many sorts of sensors, a few are listed
here
. Generally speaking, the larger the diameter of the sensor, the larger the detection distance to the bed. Note that these work well with metal beds (Iron/steel better than Aluminium), but will not work for glass (capacitive sensors work on glass but are prone to drift by moisture in the air, a touch sensor may then be a better alternative).


Question:
When I print large prints close to (but not exceeding) the maximum dimensions of the heated build platform on my Anet A8, the brim or skirt or the print itself is printed outside the heated bed, while there is some space left at the opposite sites. It appears as if the print is not in the center.

Why is the print not centered on the bed?
It was centered in the slicer before generating the G-code.

How can I center the print to make it fit on the heated build platform?

Answer:
When centered in the slicer correctly, without offsets defined in the slicer, the printer is most probably incorrectly configured! Luckily you can do something about that! Basically, you will have to calibrate the printer for a new center.
Printer origin?
First of all, the firmware determines where your origin of the printer is. This implies that you need to properly set bed dimensions and offset values from the end stop switches in the firmware (usually not necessary out-of-the-box, but important when a newer or different firmware version is uploaded). These offsets determine where the origin of the bed plate is located. For Marlin firmware it is very common (for most printers) to have the origin specified at the front left corner (when facing the printer). From the
configuration of Marlin
we find the origin is e.g. in the front-left corner. Note that this can be rotated 180 degrees in certain printers, so the aft-right. Also be aware that there are a few printers that have the origin in the center, e.g. Delta's and a few Cartesian printers. Marlin definition (edited snippet) of a common bed layout:
```
*      +-- BACK ---+
 *      |           |
 *    L |    (+)    | R
 *    E |           | I
 *    F | (-) N (+) | G
 *    T |           | H
 *      |    (-)    | T
 *      |           |
 *      O-- FRONT --+
 *    (0,0)
 * .(-Xh, -Yh)
```
How do I find the physical origin of the printer?
This can be tested by instructing the head/nozzle to go to e.g. (0, 0, 15) using a
terminal/console
or a simple G-code file with a move to that coordinate that you print from SD card (e.g.
```
G1 X0 Y0 Z15 F500
```
);
note a Z of 15 is chosen for safety!
. When this is performed, the nozzle should be at the (elevated, so X, Y) origin as defined by your firmware. Usually this is at the left front corner of your build plate (there may be clips there, so therefore the elevated value), but this may be different depending on the firmware settings or firmware brand.
Next step is to configure the slicer as such that this coincides with the actual origin. Incorrect slicer settings can cause the slicer to assume the origin is at a different position than your actual position. In Ultimaker Cura, the "Origin at center" is notoriously known for this when the physical origin is not in the center, but in a corner. When the slicer is properly instructed, but the origin is still not at the corner of the build plate (
beware!
in some printers the origin is in the middle of the plate) you might have incorrect endstop to origin offsets.
Determine the offset first!
To quantify the offset of the center as it is known by the printer software (firmware) it is advised to print a large square that is a few percentage smaller than the maximum size of the bed. E.g. you can create a square hull at e.g. 90 % of the dimensions of the bed (parametric designs are very useful for this purpose, see e.g.
this design
). There are many things (
```
.stl
```
models) to be found on the internet. If it includes a cross, even better as some platforms have a mark in the center of the bed.
Example of a bed center calibration model
Once printed, measure the distance from every edge from the build platform to the printed square. If you fail to print the square, please check the level of the platform;
this is also an excellent test for the level of your bed!
The measurements should give you a notion of the offset of the bed. E.g. for the X-axis you measure a distance of 12 mm on the left and 8 mm on the right (when facing the printer) you can easily deduce that the center is (12 - 8)/2 = 2 mm to the right (positive X direction). This implies that the printer manufacturer has done a lousy job by delivering you a printer with an offset bed; better said incorrectly configured in their firmware. Note this is not uncommon!
How to fix this!
Once you quantified the offset, you want to be sure that your next print prints in the middle of the bed. How to proceed? Basically there are a couple of solutions you can use, each with its own advantages and disadvantages.
A simple solution (i.e. if the printer support this) is to adjust the position of the endstops. Alternatively you can print alternate endstop holders to match the position change as measured from the calibration print.
Another simple and popular solution is applying an
offset in the slicer
. You could do that in the printer options some of the available slicers. If such options are not available, you could add
G-code commands in the start code
to create the offset (e.g.
```
G1
```
X-2 moves to the left and
```
G92 X0
```
resets the X origin). Note that this is a quick fix and should be applied wisely. The printer does not know where the actual center is! You merely changed if after the homing sequence. Exchanging
```
.gcode
```
with fellow enthusiasts with the same printer may have adverse effects.
A far better solution is to fix the center in the firmware so that the printer knows the
actual
center. This requires some extra effort by uploading firmware (files including configuration settings) to the printer or send G-code commands. The latter option will be discussed first.
A prerequisite of this method is that it requires the
G-code command
```
[M206](https://reprap.org/wiki/G-code#M206:_Offset_axes)
```
to be supported by your firmware; note that not all 3D printer firmware solutions are able to use this G-code command for axes offset definition. E.g. the stock Anet A8 runs a modified Repetier version that does not support
```
M206
```
, it would be time to upload a new firmware like e.g.
Marlin Firmware
making this particular printer safer as the stock firmware does not include thermal runaway protection! See question: "
What is Thermal Runaway Protection?
". To send G-code commands to a printer you have the option to hook up your computer to the printer over USB and use a 3D printer program that support sending commands to the printer (this is called a terminal; i.e. an interface to the printer). Programs like
PronterFace
,
Repetier-Host
,
OctoPrint
, and probably many more have such an interface. A simple alternative that works also is creating a text file (with
```
.gcode
```
extension) with the commands on separate lines and executing the "print". The following codes need to be sent:
```
M206
```
e.g.
```
M206 X-2 Y2
```
(move center left and to the back, note to use integer values, float values are not allowed!) and store this new center with
```
M500
```
.
The final, best solution is to set it fixed in the firmware. This requires an upload of a more recent configured version of an applicable firmware. See e.g. question: "
How to upload firmware to reprap printer?
". Note that there are different methods to upload a firmware to the board, it is best to search the internet for the applicable method for your board.
To do that you will have to be comfortable with computer software and tools to build source files and upload binary code to the printer. This depends on the type of firmware you choose and therefore cannot be described for each firmware in detail. Various sources on the internet describe this process. Generally speaking, it requires you to set the bed and offset values/positions correctly. For Marlin Firmware this comes down to changing the settings in the
configuration file
, this is similar in other firmware software solutions:
```
// The size of the print bed
#define X_BED_SIZE 220
#define Y_BED_SIZE 220

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS -35 ; used to be -33, so 2 mm shift to left now
#define Y_MIN_POS -8 ; used to be -10, so 2 mm shift to the back
#define Z_MIN_POS 0
#define X_MAX_POS X_BED_SIZE
#define Y_MAX_POS Y_BED_SIZE
#define Z_MAX_POS 240
```


Question:
I read something the other day about a guy who found a way to knock over completed prints with the printer head itself, then slide them to the edge of the build plate, where they fall into a box/basket. This allows printing several Eiffel Towers while you sleep for example. It doesn't work with skirts (duh), and the adhesion has to be just right not to wake up with a pile of spaghetti, but it still sounds useful.

Well, now I cannot re-find the description I read; does anyone know what this process is called? Is there an easy way I can perform such an end-of-print action on my CR-10 with a cura plugin? If such a thing takes a touch of end-time custom gcode, is there a proof of concept rough draft or demo I can start tinkering with? Any more info is helpful.

Answer:
You could cool down the heated bed (with e.g.
```
[M109][1] R28
```
) and cool down the hotend (with e.g.
```
[M190][1] R40
```
). This will usually release the print from the plate, perform the actions to move the head (e.g. go to the largest X, Y position
```
G1 X{max} Y{max}
```
, move down
```
G1 Z10
```
to then move to minimum X, Y
```
G1 X0 Y0
```
position such that it sweeps the print to the origin) that it knocks it into the basket and start printing again by copy pasting the whole G-code beforehand a couple of times. Note that this all depends on the product you are printing. You should at least use the end code scripts for the specific tasks to cool down, and start scripts to heat up again.
You can write a Cura plugin to implement a new GUI item to copy the G-code multiple times or create a post processing plugin.


Question:
I got myself the Ender 3. The Home position is about 1 mm left and 2 mm in front of the front left corner. Now, the hotend center axis is 11 mm from the carrier plate with the "Mk 10" cooler mounted right onto a pair of 5 mm pegs that are part of the plate. As I want to change to an e3D v6, which has a diameter of 22 mm, I will have to move out some distance (ca. 13 mm) to the current Z axis. This means, that any Y command will be off by this distance.

How do I reconfigure the Home position to have an offset to the 0-positions gained from the limit switches?

According to Repetier Host it runs on Marlin 1.0. Creality offers the firmware on their website as a .hex file - which is hard to edit.

Answer:
When homing the printer, the hot end carriage will be instructed to hit the (mechanical or optical) end stops. From this point a well configured firmware knows where to find the origin of the heat bed.
For the printer to know the origin of the bed, offsets are defined in the firmware from the end stop locations to the actual origin of the heat bed.
E.g. in Marlin Firmware this is defined by
```
```
#define X_MIN_POS -35 ; move the head 35 mm to the right to place the
                       ; nozzle at X = 0
 #define Y_MIN_POS -8  ; move the head 8 mm to the back (or the plate
                       ; forward) to place the nozzle at Y = 0
```
```
When you change the hardware (e.g. carriage), you need to re-calibrate the movement from the end stop location to the origin of the bed. Note that any arbitrary point on the heat bed can be used to re-calibrate this. E.g. the center of the bed can also be used, and is frequently much more easy to re-calibrate as the heated beds usually have rounded corners or are slightly larger than the actual print area (e.g. I have a 300 x 300 mm heat bed that actually measures 315 x 315 mm). Printing a large square on the heat bed will therefore give you a good impression of the offset of the nozzle due to your new carriage design.
Note that, if you cannot or will not flash new firmware, an alternative solution exists to set new incremental offset values using the
```
M206
```
command
IF
your current firmware supports
this.
A detailed description to re-calibrate is found in answer
How to center my prints on the build platform?
or in external link
Bed center calibration
.


Question:
I am wondering if this piece of G-code is valid:

G0 (Some comment (Its G0 command)) Y10 Z-5

I have tested this on my Chinese CNC machine and it strips out the comment and works flawlessly.

The machine processes this as G0Y10Z-5 which seems like the correct approach to me.

I have however never seen such comment in real CNC practise.
It would be nice if anyone is able to test it out on their CNC/3D Printer.

Many G-code simulators on the internet fail to process such a line in their parser so it makes me confused. I haven't found anything about it on RepRap Wiki or even Google.

Answer:
This is not universally valid G-code, and how it is handled depends on the implementation. You can use this style of comment on
some
machines, but not all.
The way parsing used to be implemented in Marlin (a very common 3D printer firmware), it would work fine unless the comment string included a X, Y, Z, E or F character. The parser simply looks for the first occurrence of X/Y/Z/E/F and then tries to parse the bit of text appearing after that character into a number. If the string cannot be parsed as a number, it defaults to 0 instead. For example,
```
```
G0 (Some comment containing the character Y) Y10 Z-5
```
```
would be interpreted as
```
G0 Y0 Z-5
```
and not as
```
G0 Y10 Z-5
```
, because ") " (the string appearing after the first occurrence of "Y") does not parse to any valid number. Your example happens to work fine because the comment string doesn't contain any special characters.
Marlin does support end-of-line comments, which should start with a semicolon and continue until the end of the line.
This is how it used to work in older Marlin versions. Newer Marlin versions have a more advanced parser, but it still would not play well with these parentheses-style comments. It is best to avoid them, as compatibility is not guaranteed.


Question:
I made a few successful prints since I got my CR-10 two weeks ago and I didn't run into any major trouble. The printer is new.

Today I set it to "preheat" mode while I was preparing the SD card with the settings being 210°C for the nozzle and 60°C for the bed. When I wanted to start the print I noticed that the temperature showed as "actual temperature" on the printer's screen showed 233°C and it was going up steadily while the "requested" temperature was still 210°C.

Thiking it might be a mis-manipulation on my part I powered it down for a few minutes (I got scared by the high-temp) and then powered it back on. I then immediately requested the print to start. The CR-10 heated up to the proper value, started printing and kept heating the nozzle. I stopped it at 217°C.

I looked for an answer on the internet but all I could find is people having trouble with the nozzle not heating at all ...

Answer:
This is not an easy one to solve, the firmware of the printer should be keeping the printer at a certain temperature depending on the temperature setting and the current value. If the firmware is not able to keep the temperature at the requested level, but goes beyond that level, that could be considered "strange". As it measures the temperature (and reports it on your display) it must know that it is over the limit and thus should not power the hotend.
In this process there are a few possible candidates for you to look at:
Check for a faulty
MOSFET
(sort of an electronic switch) on your controller board (is it leaking current to the hotend?).
Check and or update the current settings for the
PID
values (settings for the control loop of the hotend). The PID values control the overshoot of the temperature. E.g. is this is very large overshoot? When incorrectly configured the temperature can get higher, but normally should never increase to infinity, are you sure it keeps rising? The determination of the new values is called
PID tuning
. Important commands (that need to be send over a USB connected printer with a 3D printer terminal application like Repetier Host, OctoPrint or Pronterface):
The
M503
G-code
command shows the current settings (somewhere in the heap of all settings).
The
M303
G-code
command can determine the values.
Reflash the firmware
Replace the printer controller board
You could replace the thermistor and the heater cartridge (just to be sure, most definitely not the problem, but they are really cheap to replace). The thermistor works as it reports the temperature, and the heater element doesn't get powered by itself.
As suggested below
the most likely candidate for your problem is the MOSFET
. These are pretty easy to replace (depending on your board) or replaceable by an external MOSFET module (if you happen to have one lying around).


Question:
I am searching for 3D printing filaments, that are suitable for outdoor purposes, but printable on unheated beds.

I will mostly use it for sensor node enclosures (should withstand temperature up to 50°C/120°F) and car accessories (70°C/160°F).

If it requires annealing, it should have low shrinkage, since I will be printing parts that will fit into each other.

Answer:
This is not an easy one to solve, the firmware of the printer should be keeping the printer at a certain temperature depending on the temperature setting and the current value. If the firmware is not able to keep the temperature at the requested level, but goes beyond that level, that could be considered "strange". As it measures the temperature (and reports it on your display) it must know that it is over the limit and thus should not power the hotend.
In this process there are a few possible candidates for you to look at:
Check for a faulty
MOSFET
(sort of an electronic switch) on your controller board (is it leaking current to the hotend?).
Check and or update the current settings for the
PID
values (settings for the control loop of the hotend). The PID values control the overshoot of the temperature. E.g. is this is very large overshoot? When incorrectly configured the temperature can get higher, but normally should never increase to infinity, are you sure it keeps rising? The determination of the new values is called
PID tuning
. Important commands (that need to be send over a USB connected printer with a 3D printer terminal application like Repetier Host, OctoPrint or Pronterface):
The
M503
G-code
command shows the current settings (somewhere in the heap of all settings).
The
M303
G-code
command can determine the values.
Reflash the firmware
Replace the printer controller board
You could replace the thermistor and the heater cartridge (just to be sure, most definitely not the problem, but they are really cheap to replace). The thermistor works as it reports the temperature, and the heater element doesn't get powered by itself.
As suggested below
the most likely candidate for your problem is the MOSFET
. These are pretty easy to replace (depending on your board) or replaceable by an external MOSFET module (if you happen to have one lying around).


Question:
Is hot glue suitable for FDM printing, or some process similar to it?

I think it has all of the required properties, and could produce a flexible transluscent print.  It's cheap, hotends are cheap, and the technology has been around for a while.

I couldn't find any examples or anyone talking about such a material for use, on here or the general Internet.  I wonder if there are tradeoffs or challenges that make it not worth pursuing.

Answer:
You could mount a hot glue gun to a 3D positioning frame, but you would immediately notice the following:
Hot glue sticks are fat, so you lose a lot of precision for each feed/retract increment. I.e., it's a lot harder to get precise feeds with a fat stick because the stick size is so much larger than the nozzle.
Hot glue sticks are short, so you would to create a filament to spool the stuff or come up with a glue stick feeder.
Hot glue melts at 120 °C and common plastics such as nylon melt at much higher temperatures. So hot glue would make an AWFUL structural part like a stepper mount. Even PLA barely deals with stepper temperatures. Note that temperature tolerance is irrelevant for costume parts.
Hot glue is soft, which makes it a great glue, but not very stiff for, say, making parts for a 3D printer. However, the parts might be fine for  use only in costumes, etc.
But, if you then used your 3D glue printer to dispense glue for gluing stuff together, well...that might be valuable. :D


Question:
I own a DIY Hypercube Evolution equipped with Tevo Titan extruder, Clone Chimera hotend and Capricorn's High-temp PTFE tube. I use RAMPS with Mega and A4988's.

During prints, my extruder motor randomly clicks. I touched the filament and during the clicks I'ven't felt any problems with extrusion. I looked at the motor shaft to control if it clicks at special angles or randomly, but it clicks randomly. My prints do look very good: clear and shiny.

Do you have any suggestions? (the sound really gives me headache)

Answer:
Even though you may have acceptable extrusion, any clicking from that area of your printer is likely to be a missed step on the extruder motor. This may be insignificant with respect to print quality, but as you suggest, it is an irritation.
If you are confident that your nozzle is clean of debris (which is likely), you could consider to raise the nozzle temperature a few degrees. If the nozzle is not applying enough heat to the filament, it may resist being forced through and a click representing a delay, allows that much more heat to be applied.
You should not have to increase by much, certainly no more than five degrees.  It's also possible that you can slow the feed rate a bit to accomplish a similar result.


Question:
I specifically want to test

calibration

tolerances

precision

accuracy

I'm having trouble with Print in Place models and I'm trying to find out if there's something I can do to improve my print quality.

The printer I am using is a Kossel clone, specifically a FLSUN QQ and assume FDM printing.

Answer:
The best place to start looking is to go to
Thingiverse
and search on '
benchmark
'. There are a great many models there intended to test various aspects of printing. In fact you could search for example '
calibration benchmark
' or '
calibration test
' and get more specific examples.
Actually,
here
is a collection I just made today of the benchmarks I thought most promising. Disclaimer: I haven't tried them yet!


Question:
I need to replace the lid of my water kettle and am searching for a filament, that is suitable for this purpose. The requirements are:

Stable at 100°C (212°F)

Resistant to steam/moisture

Food-safe

Has anyone experimented with this or similar purposes?

Answer:
There are few materials that go up to that temperature and beyond.
A very nice generic overview is given by
Simplify3d
:
This figure shows an overview of many of the used materials in 3D printing
When looking closely, and without pointing to specific brands (to avoid a commercial posting), your best chances for appropriate filaments for your application is to look at Nylon, Polycarbonate (do not consider Polypropylene; that is very difficult to print) or (not mentioned in the overview as they are more recent filaments) Co-Polyester polymers.


Question:
High performance polymers are becoming available for specific applications.

One of such materials is PEEK (PolyEther Ether Ketone), a thermoplastic polymer in the polyaryletherketone (PAEK) family. PEEK competes with certain Aluminium alloys but is half the weight of Aluminium. For aerospace application this sounds very promising!

NASA has shown that printing these types of polymers is feasible using low-cost, open source hardware.

Does anybody know why the prices of PEEK are so high?

Depending on the supplier/manufacturer you're looking at about 700 - 900 Euro per kg.

Answer:
My assumptions about PEEK filament price are:
Raw material is more expensive. Compare price of
ABS
with
PEEK
pellets.
Demand is much lower. There are not many printers able to print peek. If you manufacture PEEK filament you have to store a filament batch for longer time. Manufacturer has to calculate into price storage space, material degradation, ...
Filament machine tuning. You have to tune filament extrude machine for PEEK, which takes time because it's a totally different plastic. Maybe there is a cleanup needed after finishing a batch and switching to another material.
Working conditions. PEEK is quite smelly and I am not sure if you have to improve work conditions like better ventilation.
Research costs. You have to distribute research costs to a filament production where demand is low.


Question:
I´ve have read an article to change different pattern depending on amount of layers, but my question is if is possible to have different infill in the same part? For example:

Base: has the infill of 25 % but the same base has some tabs for screws and mount the part for this area the infill need to be 40 % or greater.

The walls and forms: this has the same of the whole part and can be filled at 25 % but some areas need to be filled at 15 % or less.

Probably someone has seen or reviewed another software to achieve this, or I'm fooling myself.

Answer:
This answer explains that you can have different infill within the same part. Firstly the implementation in
Ultimaker Cura
is described, secondly how you can do this in
Slic3r
.
Ultimaker Cura
I've used a feature in
Ultimaker Cura
that can be used to alter the infill density locally. What you need to do is load your model into Cura, then load other objects (models) at the size of the area/volume you want your infill differently and position those at the position you want a different infill. Alternatively, you can add support blocker cubes that can be used as well.  So basically, you use other models to intersect with your primary model to create intersections that can take a different infill percentage (please note that you can alter even more options, as long as you add these to the intersecting volume). This is extremely useful for lugs and brackets where you need some extra infill (e.g. extra stiffness for compression stresses) at the fastener holes. Note that this is an advanced feature which is not easy to use, but quite handy if you master it.
I could not find the video (
on second thoughts, I think it was animated GIF
) posted by Team Ultimaker, so I quote a section of one of their forum topics.
A short how-to:
(italic font is not in the reference, but added to reflect recent version of Cura)
Unselect "keep models apart"
(now called: "Ensure models are kept apart")
and "drop models to build plate"
(now called: "Automatically drop models to the build plate")
in Cura preferences
Import a second object (for example a simple cube)
Put Cura in "custom mode"
Select the cube, and use the button "per object settings" on the left side
Select "Infill Mesh"
(now called: "Modify settings for infill of other models")
and enable that setting
The cube now turns transparent gray.
Position the cube to overlap part of your model. It should overlap with the section that you want to change the infill for.
Also with "per object settings"
(now called: "Per model settings")
select the option "infill density"
Set it to the desired value. All is more or less illustrated in the screenshot below
The picture shows a cube on the buildplate with infill 20 %. Locally, with a rotated 2nd cube, the infill % is raised to 100 %.
What happens is that the volume where the cube intersects with your object is locally sliced with different infill.
Please find below another example of a simple bracket that has extra cylindrical objects loaded to create the intersections with the bracket at the fastener holes. In the
example
, the infill at the fastener holes is set to 99 %.
After slicing, you will see that the infill at the intersections is adjusted accordingly.
Note:
I've tested this in Ultimaker Cura 3.4.1, and confirm it works. I sliced a part with the inserts for fasteners and it actually is not very difficult, it just requires a little more work. You will have to make some STL's of cylinders and position them correctly. If you make your own 3D models it will be a very easy task to add extra components while you design, positioning will be a lot more easy then (as they align with your model). An example is the following linear
Z rod bracket of a Hypercube Evolution CoreXY printer
, this bracket requires local reinforcements for the bolts clamping the bracket onto the aluminum extrusion profile:
Inserts are modeled together with the development of the bracket:
When combined, it looks like this:
Now the infill can be modified locally to 100 % to increase compression strength.
Note that this will also work if you want a different infill percentage at the first X layers, just use a large cube (larger than the model) and position it correctly. Note that Cura already has an option called "Gradual Infill Steps" to adjust the density at the top layers.
Slic3r
This reference
describes how to do this for
Slic3r
in detail.
The blog describes the use of a simple volume (the green volume loaded from an STL file). After loading:
Right-clicking on the main part brought up the object settings menu.
From there, clicking "Load Modifier" and selecting the previously
saved model adds it to the part as a modifier.
The green "+" was selected and "Fill Density" was added to modifier
list and set to 100 %.
This shows that the functionality in Slic3r is very similar to the functionality in Ultimaker Cura.


Question: I have been wondering about 3D metal printing (steel, aluminium), but after a short research on google I found only too expensive printers (markforged, desktop metal and a few other industrial ones). Is there any less expensive printer that is able to print metal parts on the market ?

Answer:
Anzalone and friends published
A Low-Cost Open-Source Metal 3-D Printer
in
IEEE Access
:
This paper reports on the development of a open-source metal 3-D printer. The metal 3-D printer is controlled with an open-source micro-controller and is a combination of a low-cost commercial gas-metal arc welder and a derivative of the Rostock, a deltabot RepRap. The bill of materials, electrical and mechanical design schematics, and basic construction and operating procedures are provided.


Question:
I know very little about the history of 3D printing, except that SLA came first (in the 1980's?), and FDM development was probably held back by patents.

By 2016, very low price kit machines were available to hobbyists, in the <€300 price range, as price-reduced clones of designs which had already seen several iterations.

Was this the start of the break-out of cheap FDM machines (as opposed to the >€2000 semi-professional lab budget prototyping class), or were the earlier iterations of these kit machines also suitable/adopted by hobbyists?

I realise that early popularity would grow exponentially, but I'm thinking particularly at what point people could build a printer without needing to compile their own firmware, solder any boards, etc.

Answer:
By 2016, very low price kit machines were available to hobbyists [..]
Was this the start of the break-out of cheap FDM machines
No, not by any means. The
RepRap project
started in 2005, and by 2008-2010 there were several open-source printer designs out there that were somewhat workable for hobbyists. These designs were still quite expensive, you needed to source all the components yourself and do a very significant amount of troubleshooting.
However, as early as mid-2009 you could buy a
Makerbot Cupcake CNC
for \$750 as a kit (which might have involved some soldering) or \$2500 fully assembled (presumably without soldering, but it's conceivable it was plug-and-play). Makerbot went on to become quite a successful company, piggybacking off the RepRap project and could be viewed as the "break-out" you ask about.
I purchased my first printer kit (no soldering or firmware involved) for \$500 (plus around \$150 in shipping and taxes) in February 2014; cheap hobbyist machines were commonplace well before that.


Question:
It would be helpful to me if I knew in advance how much the empty filament spool weighs.

Not having emptied any spool yet, I can't contribute data points, but has anyone compiled a list of empty weights from various manufacturers and sizes?

Answer:
Yes, there is a table on
Reddit - Empty spool weights for estimating remaining filament
which suggests that the norm (in 2015) was between 170 and 330 grams for a 1 kg spool, superficially in a bimodal distribution clustered around the high and low points. Presumably these were for 3 mm filament, this post dating to before the popularity of 1.75 mm...
Manufacturer's have an incentive to reduce the mass of their spools, or even ship without spools, since the shipping cost will eat into their profit margin.


Question: I see plans for various spool holders, either for PLA in the open, or for whatever filament in a dry box, that use 608 bearings. Elsewhere, I see warnings not to oil your filament to make it go through the extruder better, because problems going through mean something else is wrong, and it's better to fix the other thing. So, if I use the 608's, will oil leak on the filament, and is this bad?

Answer:
Typically, oiling a filament would mean to use a vegetable based or non-petroleum type of lubricant, possibly even PTFE (teflon) or silicone. Those materials will not damage PLA filament.
Oiling filament is not the haphazard application of lubricant, however. One drop on the filament sponge guide will last a rather long time and should be given sufficient time to distribute itself in the sponge, helping it along by alternately squeezing and releasing the sponge.
Ball bearings of the type you've described will not have oil, unless otherwise modified by the user/owner. The bearings are packed with grease which will not leak out under normal circumstances. Running the bearings at high speed will cause the grease to thin a bit and perhaps drip or if hot enough will "sludge up." If your bearing grease turns to sludge, the bearing has already gotten hot enough to melt out of your plastic fitting.
For spool holder applications, you can clean the grease from the bearing with a suitable solvent (denatured alcohol, acetone, soap and hot water in a pinch) and expect little impact on the drag. The spools rotate at such slow speeds and under such small load that the bearings alone will work nearly forever. This recommendation is void in dusty environments.
With respect to oiling the filament, it's not a bad idea to have a sponge dust catcher that has no oil just as the filament enters the last open location. My bowden extruder system is nearly enclosed and the sponge sits at the very edge of the spool, while a direct extrusion system would have the sponge at the entry to the extruder gears.


Question:
Let's say I'm modeling a simple box with a lid. Just as an example, we'll say the outer edge along the top of the box is 50 mm x 50 mm. With 3D modeling software, it's easy to build a lid for this box to surround the top with an inner edge size of also exactly 50 mm x 50 mm ...but this seems like a bad idea. Surely I'll want some kind of of gap, to ensure an easy on/off. An exact fit seems like it's asking for trouble.

How much gap do we leave for this kind of thing?

Is it related to nozzle size?

I suppose it also matters how tightly you want to fit, though I expect in cases where a tight fit matters some kind of snap or clip would be used.

Are draft prints with larger layer sizes useful for figuring this, or do the rough layers make things seem tighter than they'll be in a final print?

Answer:
Short version:
basically, this depends on your printer, make, model, type, state of maintenance, extruder, slicer settings, belt tension, play, friction, etc.
Long version:
Basically your printer determines how accurate it prints; you can influence the accuracy a little by calibrating and fine tuning the printer. What regularly is done is to print
calibration cubes
of fixed size. Before you do that, you should read "
How do I calibrate the extruder of my printer?
"; this explains to calibrate the extruder. With a fine tuned extruder you could print those XYZ calibration cubes, or in your case create a box of e.g. 50 x 50 x 15 mm. When you measure the length and the width with a caliper, you will know how much the tolerances are for this print size. Eventually, you could change this by re-adjusting the steps per mm in the firmware of the printer, but this is not always a recommendation (as your steps per mm should be related to the mechanical layout of the used mechanism, e.g. the belt size and pitch in combination with the pulley and the stepper resolution).
Please also look into the answer of "
How to make moving parts not stick together?
"; this answer hints to printing a tolerance calibration model that uses diabolic shapes set apart from the outer object by several values for the offset between the pieces. When you print this you can find out what sort of tolerance works for you. Please do note that the tolerances on smaller parts may be different than the tolerances on larger parts.
The answer on your question thus depends on your 3D printing machine, but usually the tolerance values range in the few tenths of a millimeter. To enable a lid on top of a box like in your example, you need to keep the tolerance in mind when designing the lid. Usually an extra few tenths of a millimeter will do the trick, but if you make some test prints first you will know exactly.
To answer the question what the influence is of layer height on tolerance, I
quote
:
Load a 25 mm cube into your slicer and set the infill to 0%,
perimeters to 1, and top solid layers to 0. You’ll also want to print
it at a fine resolution – I chose 0.15 mm and it actualy did make a
small (0.02 mm) difference in the wall thickness as opposed to 0.3 mm.
So yes the layer height has an effect, it is very little though.
An interesting read is "
A Guide to Understanding the Tolerances of Your 3D Printer
" from "
matterhackers
".
Furthermore, when you have calibrated the printer but still run into small deviations, is that most slicers will allow you to compensate for X and Y dimensions.


Question:
Recently, I have heard people talking about masterspool, when talking about 3D printing filament.

What exactly is master spool?

Where did the idea come from and when?

Is it being widely adopted? Or to be specific, how many distributors/manufacturers have adopted this already, and is it gaining traction?

Is this something that I should get excited by?

If so, why is it such a good idea?

Answer:
A masterspool is the practice of printing your own spool out of filament, which will then be used to support your filament you purchase without a spool attached. The main idea is to create a reusable spool and create less waste.
(
NOTE: I'm in no way affiliated with MatterHackers.com, nor am I an endorser of their products.
There is also a version which
Village Plastics
has created.)
On
MatterHackers.com
website, they state:
Filament without a spool? Why are we making this? The short answer: because the community wants it. We had enough questions, comments and plenty of tweets asking if we had plans to pick up the Master Spool concept. Seeing the response and interest within the community made it clear to us: we needed to bring this idea to the States. With a joint effort between MatterHackers and Village Plastics, you can now purchase Master Spool refills from within the US.
They are tying to apply the
Reduce, Reuse, Recycle
mantra to create a cleaner environment for the rest of the world. While they are not the first to create or use a printable spool, they are pretty happy to be pressing forward with the idea of having a reusable spool and selling filament without a spool attached.
MatterHackers go on to state:
What are the benefits of the Master Spool? Not only is there the  benefit of reducing plastic waste, using a Master Spool will also reduces shipping costs for new spools, and limits the clutter from amassing of a huge collection of used or empty spools. Rather than throwing away, trying to recycle dozens of spools, or trying to come up with a way to reuse them in some (like the Spool Tool), using the Master Spool means you can use all those filament scraps you have laying around on something useful and have one spool for all of your filament.
As far as where it started, it appears to have originated with
this print on Thiniverse
created by
Dingoboy71
. A well known 3D printer named
RichRap
created the reusable spool which MatterHacker promotes, though they say there are several which will work with their product (Village Plastic says pretty much the same).
If you get excited about saving the planet, then you should be excited about this. If you are a robust printer, going through tons (hopefully not literally) of filament per year, this method will save a lot of waste in the long run.
Realize there are (as of this writ) only limited suppliers of spool-less filament, though I think the trend for this type of product will increase in the future as the idea catches on. I guess time will tell.


Question:
Let's say you're printing a container or some other object with no infill. What's a good rule of thumb for how thick to make the outside? I'm looking for something along the lines of millimeters thick per square inch of area.

I'm thinking about PLA right now, but answers for ABS and other materials are welcome, too.

Answer:
I make small objects (25mm^2) with 1 to 1.5 mm walls and larger objects (think coffee cups)  with about 2.5 - 3 mm walls.  I set the line width and number of perimeters to completely fill the thickness.
I use this for ABS and PLA.
The PLA objects have been electronics enclosures,  with internal structures to support the parts.   They aren't subjected to strong forces.   I've made small containers for stain gauges with the amplifiers,  and larger ones for greater sequences and Arduino boxes.
I've used ABS also for coffee mugs and beverage glasses,  to withstand the mass and temperature of drinks.
It can take some fussing to worry the Slic3r slicing parameters into place.  Especially with mugs the design is for function and appearance,  not for effect.


Question:
I have a printer with a 0.1 mm typical layer thickness. Of course I can choose some different sizes in Cura or other slicing software, but most prints on this machine will be .1mm. In my (admittedly limited) experience thus far, the 0.1 mm seems typical for other printers, too.

I want to get a sense of just how thick this is. I know about the paper trick for leveling the print bed, but my understanding is the first layer pushes into the bed a little, meaning it's less than 0.1 mm and so paper isn't a good example for the typical layer.

Is there a similar item with close to 0.1 mm thickness I can use to visualize this?

Answer:
Sure. Get a 0.1mm thick feeler gauge.
http://duckduckgo.com/?q=feeler+gauge+.1mm


Question:
I've just bought Anycubic i3 Mega printer and trying to level it.
So far I've printed test object and 2 others but looks like there are problems with leveling.

I want to make image of 5 small one layer squares(one in each corner and one in center). Looking for recommendations of simple software/tutorials/approaches to do it. I tried zbrush but found that it kind of complicated.

Answer:
You are probably looking for something like
this
:
Note this is for large beds (300 x 300 mm), so you would have to X, Y scale this in your slicer.
This is a simple part that is very easily generated with
OpenSCAD
3D design software (very good modeller if you are familiar with software coding), but could easily been designed in any
other tool
.
Another leveling and centering print that is created with OpenSCAD is
this
, and could be a start for you to create your own design:
Note that the file with the design is located in the "files" section.
Edit
:
Some code for OpenSCAD made within 5 minutes (I don't type fast so it could have been faster if I did not use the constants, but if you go OpenSCAD, making parametric designs is almost a must ;) ):
```
```
// Set constants as you like
width = 30;
depth = 30;
layer_height = 0.2;
first_layer_height = 0.2;
nr_of_layers = 2;
box_size = 180;

// Calculated parameters
height = first_layer_height + (nr_of_layers - 1) * layer_height;

// Draw the test object
translate([-width/2, -depth/2,0]){
  // Draw the center square
  cube(size = [width, depth, height], center = false);
  // Draw the corner squares
  for (x=[-1:2:1]){
    for (y=[-1:2:1]){
      translate([x * (box_size-width)/2, y * (box_size-depth)/2, 0])
        cube(size = [width, depth, height], center = false);
    }
  }
}
```
```
Rendered figure:


Question:
I came across this suggestion on the klipper github, https://www.facebook.com/groups/Hypercube.Evo/permalink/192106034761003/. In order to reduce the stretching in the bowden tube you can add fiberglass packaging tape lengthwise along the tube. This would decrease the elasticity while still allowing the plastic filament to run through it. Allowing you to reduce the retraction length and have better control over the amount of plastic being extruded.

Is there any reasons that this would not work or actually decrease the performance of the bowden tube?

Answer:
The question seems to be built on a false premise, namely that the major extrude/retract errors in a Bowden design come from tube stretch. The PTFE tube is
not
significantly elastic, actually it is reasonably stiff so there is minimal scope for improvement here.
A longer tube
will
contribute to degraded precision, but slack in the filament/tube gap is roughly as significant as stretch (and filament compression). Constraining the tube path may help marginally (but there is no need to 'bond' the tube). There is not much you can to to reduce the gap between filament and tube, but this will dominate the error for a long tube.
The most obvious weak point is the clip used to secure the tube at each end. I saw a review of a recent Prusa design where high quality clips were called out as making a big improvement to securing each end of the tube.


Question:
I just received my new Creality Ender 3. I was going through and checking/adjusting everything for alignment, and I noticed that when you "auto home" the print head, the nozzle stops off the front of the print bed by 5-10 mm.

Is that normal?

Is it perhaps by design to allow purging the nozzle without dumping on the bed?

It doesn't appear that there is any way to adjust the Y stop switch without making modifications to it. It also didn't look like there was any easy way to move the bed either.

Answer:
Yes, this is the "intended" behavior, as the home in relation to the physical limit position is not placed correctly about 7.5 mm into the bed in both X and Y.
to correct this, please look at the
Recalibrating Home-position
for the Ender3


Question: Cura has a layer view feature that lets you watch a simulation of the extruder head as it lays down material at each layer. Is it possible to get Cura to show a time stamp as it does this? That would let me set reminders to check a print just at certain critical times.

Answer:
These estimates tend to be very approximate, even if Cura has the accurate acceleration values for your firmware. An error of 100% is not unusual.
What you probably want is an alarm at a specific layer (a few before the critical ones). You might be able to add this to Octoprint fairly easily - it does support plugins which can provide (for example) pushbullet notifications.
I'm not sure that 'critical' points are much more likely to fail than other less predictable things (like bed adheesion failure, extruder jams, filament breaks) - unless you're testing features (and then hopefully you can print only a slice of the part).


Question:
Creality does offer its firmware on creality3d.cn as .hex files. These are pretty good as backups as one can't alter and destroy them by accident.

But... How do you install them?!

This is about installing firmware directly and without another microcontroller. To use another mictrocontroller is How to install new firmware via a Microcontroller?

Answer:
Creality also does provide an installation PDF. The process they propose is twofold and might need different settings on other machines
1
. Spots where I assume you might need to adjust are noted with
A
. Note that
this solution depends on CURA
.
1. Install the printer as a periphery machine.
This part is specific for Windows. If you use Linux or a MAC, you will need to use a different setup, but you might get the same results.
Turn on the power on the printer and connect it from the MircoUSB to a USB of the computer. This should automatically install the driver. If not, the Driver is on the SD card provided with the Printer
2
.
To manually install
```
windows Key
```
+ "
```
MANAGER
```
" and choose
Device manager
. Find the serial port that shows yellow, Right-click, choose
```
Update driver software > Browse my computer for driver software
```
. Now
```
Browse
```
, find the location of USB driver on the SD card and click
```
Next
```
.
Generally,the serial port(COM) you need update has the biggest number, but can change.
A good idea is to confirm the correct port with a software like
Repetier Host
, with which you can control the printer directly -  if it works, you got the drivers and the port correct. Also, you know the correct Baudrate.
After the driver installation, launch
CURA
to do some settings. In
```
File > Preferences
```
:
Print Window is "Pronterface UI"
A
Switch to
```
Machine > Machine Settings
```
:
Serial Port: choose the one that just was updated
Baudrate: 115200
A
2. Upload the .hex file via cura
```
Machine > Install custom Firmware
```
Make sure the printer is connected, then
```
OK
```
find the .hex file on your PC, then confirm.
Wait for the process to finish.
1 - most likely, you will have to change the baudrate
2 - This might not be true for all manufacturers, but is for creality. Other manufacturers might have different sources for these.
A - Adjust as needed!


Question:
Up till now, I've tended to scale my first layer according to the print quality, so a 0.12 mm first layer for a 0.08 mm print, and 0.28 mm for a 0.2 mm print.

After changing to a PLA which isn't sticking well, I'm wondering if the first layer is best determined by the printer/tolerance/material, rather than the overall print quality settings. Am I going to get more predictable results if I stick to a 0.12 mm first layer regardless? This is with a 0.4 mm nozzle on an Anet-A8.

Answer:
Default settings for first layer height in Slic3r Prusa Edition print profiles regardless layer height is 0.2 mm.
If you need to improve bed adhesion then try tips from this video
3D Prints not sticking anymore? Watch this! 3DP101
by Maker's Muse. It's about using glue stick and spreading it using paper towel and isopropyl alcohol.
There are other possibilities how to improve bed adhesion, e.g.
Ultem sheet
or other printing surface like
BuildTak
.


Question: Has anyone tried the steel-reinforced polyurethane timing belts? If so, how do they compare to the rubber ones?

Answer:
I do not believe the standard rubber/plastic belts have any significant stretching over time, nor do they stretch under drive motor force during acceleration (and in any case, extrusion takes place mostly under steady-velocity conditions).
While I suppose it's possible a steel-reinforced belt might have a longer lifetime, replacing a belt is quick and cheap, so why bother?
[incorporating comments]
My suspicion is that standard belts, e.g., as supplied with Prusa-clone kits will outlive us mere mortals. They can move an entire print bed+heater, so a larger print head is not an issue.
The usual problem with any belt material is ensuring there's no significant slack (which leads to backlash/hysteresis), and changing the material won't help or hurt tensioning control systems.


Question:
I have an Ender 3 which I primarily use for printing with PLA. I haven't branched out to other materials yet. :)

I've done some research into PLA fumes and airborne particulates which seemed to mention that PLA is mostly safe, but ABS is rather dangerous to print without proper ventilation. However, I understand that there isn't much research on the topic and that there haven't been many studies.

I have been keeping my printer in my bedroom, far isolated from flammable materials, which I sometimes leave on to print while I'm asleep. Should I be concerned with my health safety with respect to airborne particulates emitted by printing with PLA?

Other questions ask about ABS, but here, I'm asking specifically about PLA.

Answer:
Fire is the most obvious risk - firmware can now detect some of the more obvious failure modes such as a detached thermistor, but loose or failing connections can still overheat. A smoke alarm is a fairly obvious (but not necessarily effective) protective measure.
The risk from particulates in particular is
probably
low, but marginal health risks like this are extremely hard to analyse, and will likely take many years to manifest. The closest analogue would be to look at commercial plastics workers since they are exposed to both heated plastic, and any potential dust generated.
You could also compare the risk to other 'hobby' activities such as soldering, painting, woodworking.


Question:
I've seen many references to a FDM print being weakest in the Z axis, due to poor bonding between layers compared to the extruded walls.

Thinking about optimising this for a specific material (excluding temperature and geometry), is there an optimum layer height? It seems obvious that too thick a layer will give less compression and maybe less heat transfer into the layer below (so 0.3 with a 0.4mm nozzle might be expected to be a bit weak). Is there a single break point (i.e. less than half the nozzle is good), or are super fine layers either good or bad?

I'm specifically using PLA at the moment, in case different materials have different behaviour in this respect.

I am not asking how to model the strength of layer bonds or how to take that into account when designing a part.

Answer:
My3dmatter.com performed a
series of tests
with PLA, using "a universal testing machine". They conclude:
Layer height influences the strength of a printed part when it becomes
  thin. A printed part at 0.1mm shows a max stress of only 29MPa, as
  opposed to 35MPa for 0.2mm (21% increase).
Past 0.2mm, the max stress remains fairly constant around 36 MPa (we
  confirmed this conclusion with an extra test at 0.4mm, not shown here
  because it was not part of the same batch).
Note: It is recommended to read the full article to comprehend the complexity of the subject matter.


Question:
What are the 'headline' basic design rules for FDM?

Which topics for design principles do you recommend to someone who has purchased an FDM machine and wants to understand what is practical?  In other words, where is the place to start when you don't yet know what questions to ask?

This question and its answer discuss design tools and the workflow but doesn't cover design rules.

Design rules here meaning the principles of what is special about planning a design to be manufactured with an FDM process as opposed to traditional machining or a printing process like SLA, not the detailed/automated checks that would be applied to something like a PCB layout prior to sign-off.

Answer:
Designing a part for 3D printing often doesn't seem to have many special considerations, but I have learned the hard way, that there are some things to do differently. This is just a list of things to that one should keep in mind
in addition to basic principles of design
1
when designing parts, keeping the subsequently slicing the parts in mind too:
Print orientation
There are many ways how you could orient your print, but usually, there is one orientation, that has the least need for support. Look at your part critically and keep this orientation in mind when designing. Especially look at overhangs and bridging, and if you can get away without.
Overhangs
There are 3 sorts of overhangs:
Small overhangs ones that are neglectable.
Long overhangs which can get support.
Overhangs that can't be supported.
When designing parts, you want to make sure you only have type 1 and 2 Overhangs, as type 3 overhangs will sag and fail. Think carefully if you can rotate the piece to get a print orientation that does not need an overhang that can't be supported by an automatically generated support structure. If that is impossible, try to implement a sacrificial piece that can turn the overhang into a bridge.
Smaller overhangs can be made neglectable by adding a phase to the underside. This phase's angle is depending on the printer. In my experience, 70° is something many printers can manage, but I prefer 45° due to the ease of making them. A fuller
can
work to give a small overhang the needed support, but often has problems for larger overhangs!
Bridges
Overhangs turn into bridges if they are connected on both sides. These either have a limited length, depending on the printer you use or need a support in the center. Check if you really
need
a bridge or if you can rotate the piece to get away without.
Avoid vertical holes in bridges
It might be something that might surprise but a vertical hole or slot in a bridging part is something that often fails as the bridging strings just sag as they are terminated mid-air without a support structure and finally fall, ruining the bridge. Yet such a support structure sometimes could not be removed in all cases, so something needs to be done differently.
One such a solution is to add a 1-layer sacrificial layer on the bottom of the hole: printing a solid layer by bridging is possible, and the subsequent hole/slot can still be free. It has to be cut free after printing in post-processing though.
round holes in Walls
Round holes in standing walls can become problematic to print once the diameter gets too large. A trick to keep the upper parts of the hole to sag into the cavity, making it undersized or needing to drill it to size later. To prevent this, the upper side of the hole can be adjusted: instead of a round upper rim, turn the hole into a teardrop. This reduces the overhanging area. Keeping a 60° top angle on the hole should be fine.
If the hole is used to key an item to an axle, put the keyway to the top of the print orientation, so it takes the place of the teardrop-tip.
Some more about holes one can learn from
Makers Muse (Angus Daveson)
Reduce internal structure
I have seen prints fail for strange reasons. One of them was a piece taken from a straight up industrial design plan, then scaled down. This one resulted in
too much
tiny internal geometry, resulting in a lot of material and time wasted on printing these internal pieces that nobody could reach, that were fused together for the original gaps were already 0.2mm and less and besides that, there was the occasional print failure.
Removing any non-essential internal geometry lessens not only the printer's load, but speeds up the print, lessens the material waste and can prevent failures due to clogs or other unexpected behavior. If you can't fix it in design,
there are workarounds
, but try to need to avoid them!
Avoid Intersecting Shells
As we are at it, often game and graphic designers are lazy and use intersecting shells. These can become quite messy in the slicing step. If possible, try to avoid intersecting shells, even as modern slicers have learned to fix this by themselves by now. The results of that are not always pretty if you forget to flag the "Union intersecting shells" option in your slicer.
Sizing
We might not always be aware of it, but prints do
shrink
in the XY axis and to a different degree in the Z axis as they cool, during and after the print is done. This is what causes warping in the first place and lead to many lost prints (especially on non-heated beds). This behavior has to be taken into consideration especially when designing bores. My suggestion for this is twofold:
Intentionally design the hole to be too small and add extra wall material in slicing, then drill it up to the right diameter. Drill slowly to not melt the plastic.
Learn your shrinking parameter for the material and design with that shrinkage in mind, possibly iterating the print a few times. Note that different spools/colors of the same material might have different shrinking!
Minimum Wall Thickness
Without Arachne, a 3D-printer can not reliably print walls that are thinner than the extrusion width of a printer. The choice of the correct nozzle for an extrusion width is
a question upon itself.
. Even with Arachne slicing and variable line width, printing a wall thinner than a nozzle diameter is nigh impossible.
Tapping/Screwing/Inserts
For tapping prints directly, you need wall thickness - according to the norms - you'll need usually about 0.2mm diameter that can be tapped into for smaller standard-size threads. Using 3 perimeters with a 0.45 mm extrusion width will give walls of 1.2 mm, which I consider a rather strong wall, and provides quite some tolerance to drill up to size and then tapping screws into. You will get away with 2 perimeters for smaller thread sizes (M3 and lower), but for large ones (M10+), you will want a fourth or even fifth perimeter.
Remember though, that the
printed PLA is not good for very strong threading
:
Tapping print
s directly is pretty much only for
low- and non-load-bearing connections
. If you combine several pieces with screws, try to design the parts to make some sort of compression fit using a bolt and nut, or use several, small diameter screws with a fine thread. Avoid coarse thread if you can, stay on the small side.
If you need a
load bearing connection
with screws, the best strength comes from using a
metal insert
or provide a
space for a nut to fit into
. Metal inserts are usually placed by heat-setting them: put the heat-set insert onto a soldering iron tip and push it into the slightly under-sized hole, melting and molding the print to fit the insert, providing strong threads that are held really good in the shell of remolded plastic.
As a compromise, modern slicers allow to use modifier meshes, that could be used to increase the strength of modeled threads or holes that need to be tapped.
Do you want to know more?
CNC Kitchen (Stefan)
had made some tests on the strength of these connection type.
Print strength
Keep these general rules in mind when designing load-bearing parts:
Generally speaking, FDM prints are strongest in carrying along their
Z-axis
when withstanding
compressive forces
, as then the print layers of the shell are forced against each other. It also excels at fighting
bending
forces this way. But this orientation is also giving us the
lowest tensile strength
, as each layer boundary is a possible breaking point.
The
XY-plane
usually
excels in tensile strength
but sacrifices some of its ability to withstand compression (it is
not
proportional though).
Printing a part at a
45° angle
will give often a
great compromise of strengths
, but might need an additional surface to get a good first layer - this surface can be sacrificial with the use of support.
For deeper information on the strength of parts and materials in comparison and how to manipulate it, there are large playlists of tests made by
CNC Kitchen (Stefan)
and
Thomas Sanladerer (Tom)
Post processing
Post processing can be your best friend when printing, just as it can be your worst nightmare. I won't detail all methods of postprocessing, but some that are quite applicable.
Assembly/Gluing
Remember to design your parts with gaps for the glue when designing parts for assembly, and you might want to include guidance notches/cones or other
alignment features
to make sure the assembly aligns. This is especially needed as the parts shrink a little and have a rough surface.
If you need to assemble your part due to the available print volume, be especially sure to include ways to key the parts together. Pegs or outcroppings/indents (often called
keys
) that match up to one another make alignment on assembly much easier too, and are a different type of alignment feature. It can be a good idea to design yourself a "cookie cutter" file that is applied after designing the part that automatically includes the glue gaps and keys.
There are a lot of glues and other methods to merge the parts. A more in-depth look at some of them is
What glues for bonding printed PLA to injection-molded plastic?
but you will have to keep in mind how you want to combine your pieces in the design step - and account for it.
Print in Place/PIP
In this vein, learn the
tolerances your printer
can manage to allow print-in-place(PIP), allowing functional parts that require no assembly. PIP is something that isn't possible with subtractive manufacturing usually, but remember that in 3D printing you might need to
break
the parts free after printing from bridges or sagging. Usually, a single strong turn suffices. To be able to do this, you might want to include a position for an Allen-key to manually turn the parts.
To learn how fine your tolerances are, there are many
tolerance gauges/tests
around. A
rule of thumb
for many printers is, that 1 nozzle width is often easily achievable with a good setup, 0.5 nozzles are achievable with some effort and 0.25 is somewhere close to the 'holy grail' - you might want to change the nozzle to a smaller one in case you want to have very thin gaps.
Composite construction
There are ways to turn your (mostly) hollow prints into much stiffer versions of themselves by turning them into composites, for example by using a resin or a different hardening fluid (like foam or plaster) as a filler or coating material.
When planning to do so, remember to include inlets/outlets for it and the air. It can be a good idea to design the part in such a way that it just contains the walls and a pre-planned support structure. In doing so, remember to disable infill in the slicer to enforce the flow you want in your structure. Look at how the ribs inside of an airframe are designed for general rules on hollow parts: include holes. This allows the flow of your fluid into each and every corner instead of blocking the flow. This can also reduce the needed number of inlets and outlets from one per
chamber
to one per
part
.
Plastic Properties
Remember we work with thermoplastics. Learn what kind of postprocessing your thermoplastic allows and its mechanical properties. Some examples:
APS can be vapor smoothed with acetone.
Many plastics can be annealed by baking at or little above their glass transition temperature, increasing strength and layer-to-layer bonding.
When using power tools on plastic, use ample cooling and time, as otherwise, one quickly melts the prints!
Surface Finish
The surface of FDM prints is somewhat rough. To smooth it out there are 2 general ways: fill it up or smooth it down. If you want to fill it up, design the part
undersized
, if you smooth it down, add
sacrificial thickness
. It is common to combine both, adding body filler first, then sanding down till the print material shows through again. If doing this, make sure to check your sizing.
If there comes a lacquer layer atop, remember to account for that thickness: undersize surfaces, oversize holes!
1 - this means, that thoughts about postprocessing that are not unique to 3D printing are not elaborated on here. Examples are painting, coating or smoothing the surface mechanically.
Further reading/viewing
Further information can be gotten from these playlists, though they aim at times for newbies:
CNC Kitchen (Stefan):
3D Printing for Engineers Playlist
CNC Kitchen (Stefan):
3D Printing Tips
Maker's Muse (Angus):
3D Printint 101
Maker's Muse (Angus):
Advanced 3D Printing Tips
Maker's Muse (Angus):
CAD for Newbies
Maker's Muse (Angus):
CAD for 3D Printing