Question: I read that G-code commands can be sent through a console/terminal over USB. What is a console/terminal and how do you use that?

Answer:
There are several programs that could serve as a console to connect to a printer, put let's start somewhere: the USB connection.
Step 1: Connection with USB
When connecting the printer via USB for the first time, we will get a notification that some unknown item is connected. If we use windows we can learn what device it decided we now have via the
```
device manager
```
(
```
Windows Key
```
then typing in
```
manager
```
and
```
Enter
```
). It should be a COM Port as this picture shows.
In this case, we have connected to
```
COM4
```
. To change the COM port, we can do so via a
```
Rightclick
```
->
```
properties
```
, then the
```
connection settings
```
and
```
advanced
```
. In the new window, we can change the COM port number to anything from 1 to 256, but it is recommended to keep the number somewhat low.
Make sure you run the printer's power supply
and
the connection via USB, as you can't use motor control commands if you have the power supply for the printer off.
Step 2: Using the COM-port
Now, we need a program that can use the COM port to connect to the printer. There are, as said, several out there. One such is
Repetier Host
, which comes with slicer and a good graphical interface. Another is
Ultimaker Cura
, which has the same capacities but lacks logging of all the commands exchanged. Because many are familiar with it as a slicer, I will look at it first. As a third option, I will take a look at
Pronterface
.
CAVEAT: Only
one
program that actively uses the COM port can be properly run at the same time, as the first program accessing the port will claim all uses for the COM port till it is shut down - any program or even other instances of the same program trying to access the port after that will have no control of the port.
Ultimaker Cura
After launching Ultimaker Cura, choose your printer. many printers are available as presets by now, so just import the printer you use or make a custom profile. At the moment the latest version of Cura is 4.1.0, and will look like this:
After switching to
```
Monitor
```
, it will automatically connect to the Printer via the COM port, in my case 4.
Once more we test the connection via Home
and then use the Send G-Code prompt, confirming lines via
```
Enter
```
.
Repetier Host
After running Repetier Host the first time, you need to configure your printer.
```
Ctrl
```
+
```
P
```
opens the config window for the printer. We need to know the Baud Rate of our printer, so I looked up the documentation of my Ender3, which told me 115200 is the right setting. Most printers seem to run on this setting. The other tabs decide the speeds, extruder number and limits and the bed shape. The rest isn't needed for this. My settings for the Ender3 are these:
Ok, we made our settings and saved via
```
OK
```
.
Now, we press the Connect button on the left side of the menu:
It should change to the blue Disconnect button and display other parts of the print now, showing that we have connected. Note that at the bottom of the screen a log is filled with all the commands and exchanges.
On the right side, we now can choose the Tab
```
Manual Control
```
Before sending any commands, it is a good idea to press the Home
button. This also serves as an extra test to see if the printer is connected correctly. Now we can use the Prompt G-Code to send our commands. The commands will be put into the log below.
Pronterface
This is the first time that I used
Pronterface
. The first thing to do after downloading the Printrun package and running the Pronterface application is to press
```
Port
```
, then set the right Baudrate (115200 seems to work for many machines) and press
```
connect
```
.
The GUI will saturate and the right log will show lots of things tested in connection. Note that in the lower right of the GUI, there is a temperature curve log, which can be very handy for troubleshooting, as it shows the change over a little time.
Below the log, we find the input for commands, and if we send a command, we get a log entry of it:


Question: I have a model that contains a cavity, into which I want to insert a piece of metal, so I can use a magnet to stick to the print. How can I introduce a pause into the G-code without manipulating it manually in Ultimaker Cura?

Answer:
Ultimaker Cura contains "Extensions"; in version 4.1.0, the process is as follows:
Extensions -> Post Processing -> Modify G-code
Add a Script -> Pause at height
Choose the one that matches your firmware!
Choose the
```
Pause height
```
to match the height the insertion should take place. Usually, this is to be the layer just before the roof is to be printed to keep the inserted objects from protruding from their cavities.
Choose a park position well outside of the print. X 10 Y 10 is usually a good position for this.
Add a little retraction if you want.
In printing, you have to wait till the cavity is formed, insert the item quickly and press the control button to resume. The shorter the pause, the better the next layer will hold to the already printed.
Also, keep in mind to make the cavity a little larger than the insert, both in XY and Z, to compensate for the plastic shrinking a little and to allow the nozzle to pass well over the inserted item.


Question: I'm making a hybrid 3D printer and circuit etching (CNC milling) machine that can both 3D print and etch prototype circuit boards. I'll be using Marlin firmware with an Arduino Mega & RepRap 1.4 board. It will have a 3D printer head and a milling head side by side. I'd like to have it be able to read both .gbr (for circuit etching) and .gcode (for 3D printing) files. How should I configure Marlin to read both types?

Answer:
You can use both .gcode and .gbr files one one machine. We do it where I work.
However, when we make prototype circuit boards, we don't print them; we acquire circuit board blanks, and then we either:
Use a diode laser to burn off the top layer of garolite for isolation traces, then do a chemical dip to remove that copper, then another laser burn to expose pads for surface mount components; or
Use a spindle tool to remove the top layer of garolite where needed for pads, as well as mill through the copper layer for isolation traces.
We have not found a printable material that has the conductivity we want in a circuit board.
Source: I work for
Hyrel 3D
Note: we don't use Marlin on Arduino, we use in-house firmware on STM32F429 boards.


Question:
When making a cylinder, sometimes I need to only take a pie slice. I'm currently using this neat trick to make pie slices for angles under 90 degrees. However, I have need of a few angles over 90 but under 180 degrees. Is there a way to generalize/extend this to work for these bigger angles?

module pie_slice(r=3.0,a=30) {
   intersection() {
    circle(r=r);
    square(r);
    rotate(a-90) square(r);
  }
}

pie_slice(r=10,a=15);

Answer:
My current workaround is to use
```
union
```
instead of intersection. Unfortunately, that means I have to use an
```
if
```
clause which makes the code have two paths instead of one clean approach. Also, unlike the above method, this does not result in a clean cylindrical shape but must instead by combined with a proper cylinder to get the final pie slice
```
```
size = length + 2;
    if (angle_deg <= 90) {
      translate([0,0,-1])
      intersection() {
        cube(size);
        rotate(angle_deg-90) cube(size);
      }
    } else if (angle_deg <= 180) {
      translate([0,0,-1])
      union() {
        cube(size);
        rotate(angle_deg-90) cube(size);
      }
    } else {
      echo(str("FAILURE - Angle cannot exceed 180"));
    }
```
```


Question:
I'm printing on an Ender 5 with the default flex/magnetic build surface.
I read that PLA and PETG may sometimes be printed without any bed heating at all and also that bed heating is the main contributor to the power consumption of a printer.

As I do see that bed heating definitely helps with the first layer adhesion I did not want to turn it off completely, but I did start experimenting with turning off bed heating after all solid bottom layers have printed (using the ChangeAtZ script in Cura) and so far I haven't seen any negative effects, especially no warping (I am usually printing with a brim or raft; I think that might also help in that regard).

Am I missing something? Why is anyone keeping the bed heated for an entire print?

Answer:
All the valid points of bed shrinking and dislocating your parts when cooling from the other answer aside there is also the added complexities both in testing reliability of such a thing that may or may not be applicable to all materials.
The added complexity to the slicers to figure out when it is safe to turn off the bed which I would imagine depends on part footprint. I also sometimes print several parts sequentially in the same job so then it would need to know that and time the bed heating correctly or pause and wait for bed between parts.
I would also categorize printer power use as trivial (order of three 60W lightbulbs), but considering millions of machines worldwide economics of scale does kick in.


Question:
My local library has a 3D printer (Lulzbot Mini) for patrons to use. The prints are limited to 4 hours and if I go after work I really only have two hours before the Library closes. The software at the Library will give an estimated time, but I would like to be able to estimate the time before I get there.

Currently I have been creating my designs in TinkerCad and then I export the STL file. From the STL file I can find online estimators that will tell me how much material but nothing that says how long it will take to print.

Is there a way of calculating the estimated printing time from a STL file for a given printer?

Answer:
There is no way to estimate the print time of an STL file directly.
The print time is based on the number of instructions in the g-code file plus the time it takes to move the effector (the hot end) around the build area. The only way to compute that is to know what settings their slicer is using and then slice your stl the way they will; and this is assuming that you have the same slicer software. If you manage to do that, then the slicer software will give you an estimate.
Here is what you would need to do:
Get access to the same slicing software, and obtain a copy of
the profile that they use to slice with. The nozzle diameter, feed
rate, layer height, and infill settings will affect the print time.
Import your stl into the sofware and "slice it" There will usually be a large button that is used to generate the g-code. There are quite a few slicers that will output the print time into the text of the g-code. They may also show the print time on the UI during slicing.
alternatively: Email the stl to the staff at the library, and them to generate an estimate for you. They might just do it.
However, that estimate could be incorrect. It will depend on the printer itself. As an example: the time it takes to heat the bed and the hot end is never included in the time estimate the slicer gives.


Question:
I'm making a Circuit etching machine (CNC) and I need a good DC motor and drill bit for the spindle.

My machine should be able to etch, drill, and cut:

Etching: take copper off the surface like chemicals or a laser would

Drilling: drill holes for THT (through-hole) components and possibly 2-sided boards

Cutting: cut out a piece of the board (cutting a big piece in half or cut a circle out of a big piece)

I'd like to have 1 drill bit work with all 3 functions if possible. Having to switch out different bits is OK but a single bit is prefered.

What sort of specifications should my spindle DC motor (rpm, voltage/amperage rating, ...) and drill bit (material, size, angle, ...) have?

Answer:
There are several sources of PCB "etching" bits.  They tend to be single straight flutes and high angle, very pointy bits.
For the motor, high speed is good.  Look for 30k+ RPM.  The main thing to be concerned about is the amount of runout, or wobble in the tip.  With a tiny tip, you can't afford much runout at all.  It will broaden the gap you are cutting and put stress on the bit, probably snapping it.
The key to low runout is very careful alignment of the chuck that holds the tip with the shaft of the motor, and a collet chuck to hold the tool.
The power needs aren't high since the speed is high and the cuts are light.  I would think that a 250 watt motor should be way more than sufficient.
The question now asks for drilling and routing, which should work better with the high-speed spindle.  30k is better for the tiny drills than a much slower spindle.  These are hurt by run out.
Usually the drill bits are made of carbide.  For cutting, carbide router or file bits are used.  All drill-bits and router bits and copper cutting bits I have seen for sale have 1/8" or 3mm shank.


Question:
I'm doing some research on what types of LCD displays can be used to filter and pass UV light for resin curing - specifically in the context of building a DIY 3D SLA printer.

The community commonly uses the Sharp LS055R1SX03 module. Looking through the datasheet, there doesn't seem to be any information pertaining to the characteristics of the device when passing UV wavelengths. Is there something special about this module that allows it to filter/pass UV wavelengths compared to other common LCD displays?

Answer: I am not an expert by any stretch but I hope this helps, but these are regular old TFT LCD screens. You can even get 4K ones and use them for the same process. You can for example pick up 4K displays such as the H546UAN01.0 and do the same with them.


Question:
I just got my first 3D printer (Creality Ender 3) on Friday, 2 days ago. It works great, but for some reason I'm getting a lot of stringing on my prints, especially the ones where the extruder head has to move a long distance between columns/posts, etc.

I'm using Hatchbox "True White" PLA, which has a recommended temperature range of 180-210 °C. I've tried printing at 200, 190, and 185 °C and didn't see much improvement. I've also made sure I've enabled the 'retract' setting in the slicer (4.5 mm) and verified the printer is retracting when it should.

I'm not sure what else I can try... any suggestions?

Answer:
4.5 mm is a low retraction distance. Cura's default is 6.5 mm, and the Ender 3 profile provided with Cura sets it to 6 mm. The first thing you should try is increasing the retraction amount up to at least 6 mm. Also, make sure you actually enabled retraction. I saw one question here where a Cura user had enabled "Retract at layer change", which
does not
enable retraction (but of course it shows the options like retraction amount since you need to be able to select it for this too).
Your low nozzle temperature of 185 °C is also a problem. You'll have very low flow at that temperature, resulting in under-extrusion and pressure building up in the nozzle instead of extruding the material. That in turn will make it so, even after retracting, there's still material (and pressure) at the nozzle and it will keep oozing, unless you set a
really
high retraction amount (and even then problems will build up over time during the print, but you might get lucky and not see them). The only way to print PLA at 185 °C is really,
really
slowly.
In general, some people would also recommend trying a different filament, based on reports that some vendors' PLA oozes and strings badly, but I don't think that's an issue for you. I use Hatchbox filament on my Ender 3 all the time and never have a problem with stringing from it. And even if the filament is prone to stringing, you can almost surely avoid it with proper settings. Even very soft flex filaments can be printed on this printer without stringing as long as your retraction, temperature, and speed are tuned to avoid having pressure at the nozzle during travel moves.


Question:
I have a Tevo Tornado Gold 24 V. I want to use this LJ12 A3-4-Z/BX Inductive NPN NO 4 mm with 6-36 V operation current as a Z probe. I do not want to fry my machine by putting in 24 V into the sensor input.

What do I have is a 12 V, single channel optocoupler isolation module.

I want to know if this 12 V optocoupler module can be used with a 24 V power supply, or do I need another module in order to prevent me frying my sensor.

If I do need another what would I need?

Answer:
Not using a 12 V rated module
"on its own"
.
Using a 12 V/5 V optocoupler to try to connect 24 V to the 5 V circuit is running the optocoupler outside of its rating, meaning you will destroy it, either immediately or after a short time.
A properly rated one
To shield the 5 V against the maximal 24 V from the probe without extra parts, you will need to use a 24 V/5 V optocoupler.
Trickery with voltage dividers
With a 50 %
voltage divider
made from two properly rated resistors, you could limit the voltage to the optocoupler, which in turn would turn the 24 V signal into a 12 V signal, which would protect our optocoupler and the board beyond.


Question: I'm trying to make a water insulated 1 cm3 (1 ml) transparent container and I bought some plexiglass, I cut and glued some pieces together but it looks really crappy and barely holds the water in. I was wondering, is there a transparent material (similar to plexiglass) that can order to 3D print the container out of it? Also, if 3D printing is not the best option, where can I order around a 100 pieces of 1 cm3 transparent water insulating containers with caps?

Answer:
Yes. You'll probably want to use SLA or Polyjet printers with transparent resin. For example, here's
Shapeways' page on transparent SLA
and
their page on Polyjet
(which says you need to phone them for transparent Polyjet parts as their online order system can't handle it).
FDM printing with transparent materials doesn't usually result in parts that look like transparent injection-moulded parts, because the lines of material laid down by the printer are visible. There are
some techniques to make this better
, but a printing bureau is less likely to offer this kind of special handling.
In any case, you should discuss your requirements in more detail with suppliers, and they'll be able to advise whether they offer any manufacturing processes that meet your needs. In particular, if you need your containers to be food-safe, you should mention that at the start, as it'll rule out a lot of possible suppliers, machines, and materials.


Question:
I have an Anet A8 and have a problem with my first layer. I printed nice prints but starting today the first layer is tearing in the middle:

Any idea how to fix this?

Answer:
The great pics really help with the answerability of this question. From how catastrophic the failure is, and how it's clearly independent of any specialty needs for the particular print such as tiny bed-adhesion contacts, sharp overhangs, bridges, etc. this is definitely not a problem with temperature. Different people recommend different temperatures for PLA, but I find that 210°C works well for me, and if you go much lower you'll hit problems getting the needed extrusion rate for anything but slow print speeds.
I've seen nearly this exact phenomenon before, so I knew it was probably a matter of the bed being too high, blocking extrusion of the first layer and forcing what little material can escape out to the sides of the nozzle, then tearing into it when the next adjacent line is laid out.
If I didn't know that, though, I'd still start looking for a source of the problem that's related to extrusion rate. Something was clearly wrong with getting the right amount of material in the right space, which indicates to me that there's either too much material (overextrusion/wrong filament diameter selected) or too little space (bed to high).


Question:
I'm looking to 3D print a structure that won't deform in high heat, up to about 220 °C. The filament itself can be 3D printed all the way up to about 380 °C.

PEI seems like it could be a viable option. I found some here. This PEI filament  specifies the glass transition temperature at 217 °C.

Would this filament work? Are there any other types of materials that would fulfill this engineering requirement?

Answer:
Your expected operating temperature exceeds the glass transition temperature by 3 °C. This implies that the structure will become weak and can deform under load.
Note that you cannot simply print PEI on a normal machine, it requires a special high temperature capable printer with hot end temperatures up to 400 °C and heated bed over 120 °C up to 160 °C, furthermore it will need a heated chamber (up to about 80 °C) which requires special care to cooling and placement of electronics and motors.
Not having specified what kind of structure you require, you could look into steel.


Question: A few minutes after finishing a print job, the filament is solidified in the nozzle and the nozzle-throat. When I start another print job a while later, the filament is not sufficiently melted and the nozzle is obstructed. Do I need to clean the nozzle after every print job ? or is there a practical method to overcome this difficulty ?

Answer:
Your solution will not cool all sides effectively. Firstly don't use zip ties; get thermal tape.
(
https://www.amazon.com/Thermal-Interface-Products-Heat-Sink/dp/B00QSHPH8E/
Secondly, the heat will need to travel around the outside of the motor to get from the side that doesn't have the water block. Its expensive but you could use
Pyrolytic Graphite Sheets
to wrap around the outside of the motor, to get the heat to the water block faster.


Question: When go to export a model using Fusion 360 or Meshmixer, I see that there are two options. Could the final model be affected by the format chosen at the time of saving?

Answer:
I have experienced problems on occasion when using a binary exported Meshmixer model. The slicers used have been Simplify3D and Prusa Slicer 2.0 and possibly an earlier version. I've not attempted to resolve the problem other than to change that specific model to export to ASCII which then solves the problem. ASCII files will be larger but that's not a significant factor, in my opinion.
If you are using a program which fails to properly process a binary export, it's simple enough to overwrite the model in ASCII form.


Question: Why don't 3D printer heads use ceramic inner walls? PTFE tubes melt with high enough temperatures and all metal ends risk jamming as heat makes its way up the head.

Answer:
Because PTFE doesn't transmit heat very well? The whole idea when using a PTFE tube (and this is just my understanding ... which could be wrong), is for the tubing not to transmit heat, therefore allowing the filament to pass through it without melting or at the very least, collecting a lot of heat along the way (which helps prevent jams). PTFE does a pretty good job of standing up to heat while accomplishing the task at hand. Ceramic does an
excellent
job of standing up to heat. The problem is, it will pass the heat along to the filament, most likely melting it, thus causing it to deform and jam before it gets to the hot end. This would then become a maintenance nightmare.


Question:
I've just built my son's A6 and have connected all cables apart from the last power cables. The mainboard says hotbed line and extruder line but the cable says heatbed.

The cables are two red which are crimped together and two black crimped together.

All of the videos online show a different mainboard and connections.
There are more connections than cables because the wires are crimped.

I can't get my head around which wires go where, any ideas?

Answer:
The manual appears to be available here,
Installation Instruction_Anet A6 3D Printer - Elektor
However, according to
this comment
from
Hard copy of the build guide?
, there is a mistake in the PDF of the manual, with respect to the heatbed, and as such, it is better to follow the videos:
I find it is better to use the 3 videos:
3D Printer Instruction--Anet 3D Printer A6 Assembly Video 1
3D Printer Instruction--Anet 3D Printer A6 Assembly Video 2
Printer Instruction- A6 - Hot Bed Level Adjustment and Print Test
Only errors in the videos and i believe the instuction the Hetbed
fixing plate i have build diffrently , rotated by 180 degrees
vertical, since it is better for the belt and somewhere in the video
during fixating of the end-switch and the blower he interchanged the
screws.
However, looking at the manual, if it is to be believed, then be aware that
as well as
one connection for the extruder motor, there are two connectors
each
for
both
the extruder and the hotbed heaters:
One for the separate heating elements, of the extruder and hotbed respectively, and;
One for the thermistor sensor (both the extruder
and
the hotbed have separate thermistors).
This makes
five in total
for the extruder and the hotbed combined.
However, the power connections for the Extruder
motor
has four pins (in white at the top), whereas the heating elements for the hotbed and the extruder have two pins and are of a different shape (in green on the left). The sensor connections for both the extruder and the sensor have three pins (in white at the bottom), but it should be easy not to confuse them, so long as you follow the wires to check to which component they go to.
Additional points to be aware of
From
this comment
in the same thread:
I just built an A6 three weeks ago and with the videos it is really a
breeze to assemble the unit.
Just pay attention to the heat bed mounting plate as it is installed
bottoms up in the video. The bar connecting the outer two plates where
the heat bed is finally mounted should be below the plates, not above
as in the video.
Also, if you still have time, order some decent toothed belt, Igus
Drylin RJ4JP-01, and toothwheels for the Y and X belts and replace the
original pulleys, bearings, and belts before you even assemble the
unit. I just changed mine last week and it does make a hell of a
difference - with this little upgrades (cost me less than 30$ for
everything - at Amazon) you upgrade from an okay printer to a really
decent machine.
The belt:
https://www.amazon.com/Anycubic-Meters-Timing-Pulleys-Printer/dp/B0152ZNDLK
The pulleys:
https://www.amazon.com/Aluminum-Bearing-Timing-3D-printers/dp/B0188HW4Z0
The bearings:
https://www.amazon.com/Printer-Solid-Polymer-LM8UU-Bearing/dp/B06XPRCMJS
(actually, you need 8 pieces - not seven as in the images - 4 for the
Y-axis and 4 for the X-axis)
The above are not the actual articles I've bought because I am from
Europe where Amazon sells in different quantities.
If you want to go on the safe side, grab a second power supply and two
MOSFET boards to remove the high current from the mainboard:
PSU:
https://www.amazon.com/eTopxizu-Universal-Regulated-Switching-Computer/dp/B00D7CWSCG
(just as an example)
MOSFET:
https://www.amazon.com/Wangdd22-Printer-Expansion-Heatbed-Current/dp/B01MY50JL3
Power socket and switch:
https://www.amazon.com/URBEST-Module-Switch-Certification-Socket/dp/B00ME5YAPK
Last recommendation: get some 3mm borosilicate glass to lay (clip)
over the heatbed. This will make the prints stick better and also
provide a perfectly flat surface for the builds (still, you'll need to
do the levelling)
Glass:
https://www.amazon.com/Signstek-Printer-Tempered-Borosilicate-2132003mm/dp/B00QQ5Q3BI
When assembling the heatbed mount, pay lots of attention to the 16
screws. Tighten them one by one diagonally and move the bed around. If
the bed feels stuck, loosen the last screws and shift the mounts
around a bit. The lighter this mount moves, the better your prints
will be.
One thing that you must be aware: This printer is a great little unit,
but it needs love, dedication and plenty upgrades. Out of the box it
works okay, but with the upgrades it becomes a really good unit.


Question:
You can see small gaps in the print which looks like under extrusion (see image below).
What is the reason for that?

I've tried smaller retracting distances. Temperature looks stable.

Print settings:

PETG from Extruder

245 °C Printing temperature

50 mm/s print speed

25 mm/s wall speed

30 mm/s retracting speed

1 mm retraction distance -> stringing...

Print cooling fan is enabled

Setup:

E3D Titan Aero

Duet Wifi

1,5 A Motor current for feeder motor

250 mm/s2 feeder max acceleration

Slicer:

Ultimaker Cura 4.0

Answer:
Here's your problem:
1 mm retraction distance -> stringing...
If you have stringing, that means that material that was supposed to end up as part of printed lines instead ended up somewhere else, leaving less material (underextrusion) where it was actually wanted. This particular test piece may not exhibit stringing, but it's likely that it occurred interior to the piece, in the infill region. Contrary to widespread(?) opinion, stringing here is not harmless. It's just not visibly ugly. But it still messes up the surface quality, and even more importantly the strength, of your print.
You don't say if your printer has a bowden extruder or direct drive. If a Bowden, the 1 mm of retraction is virtually useless; a typical Bowden system has more than 1 mm just of
compression
between the extruder gear and the hotend, meaning that retracting by 1 mm does not pull the filament back out of the hotend at all, and doesn't even relieve all the pressure that's pushing melted material out. I would recommend an absolute minimum of 5 mm for Bowden type extruders, unless your printer firmware has linear advance (Marlin 1.1.9+ or comparable features in other firmware) in which case you might be able to reduce it some. For direct drive, I don't have experience, but 1 mm is still probably too low; 2.5 mm is the believable recommendation I've heard.
In addition to retraction, you can further reduce material loss to stringing/oozing in the infill region by turning on Ultimaker Cura's "Zig-zaggify infill" option, which helps avoid in generating travel without retraction over unprinted area within the infill zone (see e.g.
this issue
). Turning slicer setting "combing" to "off" is an even more extreme option here. Of course make sure retraction is really on (not "retract at layer change", which is a separate, mostly useless option) and make sure "retraction minimum travel" is set low (something like 150 % of the nozzle width or less) to prevent retraction from getting skipped on short travel moves.
I also just noticed you wrote:
I've tried smaller retracting distances...
This was probably based on erroneous advice. Reducing or eliminating retraction does not mitigate these sorts of problems; it creates them. The only reasons to reduce retraction distance are to fight problems with the extruder gear grinding down the filament after repeated retraction, and problems with jamming the path into the hotend due to pulling molten material back into the cool part where it then solidifies and jams. If you're not having such problems you should not reduce retraction. If you are having such problems, you should try to fix them in other ways that still let you keep the necessary amount of retraction not to have catastrophic print quality problems from material coming out in the wrong places.


Question: Do we need mold release agent in 3D printing mold? If it is not used, what effect will it have on the product?

Answer:
Welcome to the 3D Printing Stack Exchange site.
Used in Casting
A mold release agent is commonly used when a part is cast.  The release agent is placed on the inside of the mold before the liquid object is added.  As the object becomes solid, the release agent prevents the object from adhering to the mold.  As a result, the objects are easier to pop out of the mold, and in some processes, the mold can be reused.
3D Printing is Different
A mold release agent is used to allow the desired part to be separated from the mold.  In FDM (thin plastic extrusions bonding together into objects) 3D printing, the object is surrounded by air, except for the bottom where the object contacts the print bed.
Bed Adhesion
For most materials, getting the bottom of the object to stick firmly enough is the problem faced, rather than making it easy to remove.  In many cases, a compound is placed on the top of the bed to help the plastic stick to the bed.  It is a "mode adhesion agent" rather than a release agent.
For some combinations of materials, the bed material and the plastic have a particularly strong adhesion, such that it can be difficult to remove the object without damaging the bed surface.  Notably, this occurs with a PEI bed and PETG plastic.  In this and similar cases, the mold adhesion agents can be used on the bed.  This slightly separates the plastic from the bed material, and we can avoid bed damage.
Internal Adhesion
With multimaterial printers becoming more common, there are cases where two parts which might touch and stich during printing should be isolated during the printing process.  A second (or third) material can be used to isolate the parts.  If the isolation material is sufficiently different from the desired objects, it can be removed by a solvent.
This approach is limited to cases where the objects should be separated by at least one printer thickness of the soluble material.


Question: I am a fresh graduate student in 3D metal printing. My undergraduate major is mechanical engineering. Later research will focus on the process of metal 3D printing. I hope that you can recommend some excellent 3D metal printing books for learning.

Answer:
This is a free ebook that I have perused briefly which it looks interesting, and it is free (did I say that already?)
3D Printing of metals
Manoj Gupta
ISBN 978-3-03842-591-5 (Pbk);
ISBN 978-3-03842-592-2 (PDF)
Three other books that
might
be of interest are:
3D Printing with Metals for Design Engineers, Explained
Ann R. Thryft
Downloadable free ebook, but some sort of sign up is required
Additive Manufacturing of Metals: The Technology, Materials, Design and Production
,
Yang, L., Hsu, K., Baughman, B., Godfrey, D., Medina, F., Menon, M., Wiener, S.
ISBN 978-3-319-55128-9
Additive Manufacturing of Metals: From Fundamental Technology to Rocket Nozzles, Medical Implants, and Custom Jewelry (Springer Series in Materials Science)
Although, as the title contains a (rather obvious) mis-spelling, it does not bode well for the rest of the book.
John O. Milewski
ISBN-13: 978-3319582047
ISBN-10: 3319582046


Question:
For the geometry I am making, I want to extrude each face individually along its normal.

This is a standard procedure in 3D modeling software like Blender; see Example 3 here.

Is this possible in OpenSCAD?

Answer:
Extruding faces is only possible on 2D polygons. From a 3D object you cannot capture the face and extrude it. To extrude "faces" you would need to define the shape of the face and extend it in the third dimension of your choice. This way a 3D shape is created that could be concatenated (joined using e.g.
```
union
```
) to the original shape. For the extrusion, the function
```
linear_extrude
```
is available:
```
```
linear_extrude(height = fanwidth, center = true, convexity = 10, twist = -fanrot, slices = 20, scale = 1.0, $fn = 16) {...}
```
```


Question:
I am having a few problems with my BLTouch. I have calibrated it several times using different methods and get the nozzle being 1.3 mm lower than the BLTouch pin so a Z offset of -1.3 mm. This works fine for auto homing, bed levelling and using code G1 Z0 to lower to where needed. However when using Cura to print the nozzle homes exactly as it should then drives the nozzle in to the bed as it starts or tries to start to print and not just a little bit either. Anyone have any ideas?

Start G-code is:

G28 ;Home
G29 ;Probe
G1 Z15.0 F6000 ;Move Platform down 15 mm
G92 E0
G1 F200 E3
G92 E0

Answer:
You should be able to offset this with a
```
G54 Z-1.3
```
-
if your setup accepts these gcodes
.
If you do this, always add a
```
G53
```
to the very start and just before the
```
M30
```
to clear all offsets after job finish (or in the event of a cancel, at the start of the next job).
I'm not experienced with a wide variety of printers or firmware, but our repetier-based printers (and we use the same controls for our refurbished Fadal CNC machines) use G53-G59:
As explained in this tutorial from cnccookbook.com
:
Basic work offsets are very simple to specify: simply enter one of G54, G55, G56, G57, G58, or G59. [...] When you execute the work offset g-code, the XYZ offset will be added to all of your coordinates from that point forward.
As detailed on Wikipedia
:
G54-59
: Have largely replaced position register (G50 and G92). Each tuple of axis offsets relates program zero directly to machine zero. Standard is 6 tuples (G54 to G59), with optional extensibility to 48 more via G54.1 P1 to P48.
And on the gcode dictionary provided by Hyrel 3D
:
G54 through G59 - Set Offsets
G54, G55, G56, G57, G58, and G59 will each store and invoke offsets in the X, Y, and/or Z axes for all subsequent moves. Any values not invoked will remain with their previous value (0 unless earlier specified otherwise).
X is the offset in mm in the X axis.
Y is the offset in mm in the Y axis.
Z is the offset in mm in the Z axis.
Here is an example:
```
G54 X100 Y-50
```
This command is decoded and executed by the printer as follows:
G54 (set offsets)
- X100 (+100mm to all X coordinates)
- Y-50 (-50mm to all Y coordinates)
Note that this differs from an M6, where the offsets are only applied to a SINGLE tool position.
Disclaimer: I work for Hyrel 3D.


Question:
I have ordered a dual hotend Chimera and it came with 2x 12 V heater elements (in my rush I forgot to order the one with 2x 24V).

Is it possible to run these 12 V heater elements in series?

I am planning on running this with an SRK 1.3 board.

Answer:
You should be able to offset this with a
```
G54 Z-1.3
```
-
if your setup accepts these gcodes
.
If you do this, always add a
```
G53
```
to the very start and just before the
```
M30
```
to clear all offsets after job finish (or in the event of a cancel, at the start of the next job).
I'm not experienced with a wide variety of printers or firmware, but our repetier-based printers (and we use the same controls for our refurbished Fadal CNC machines) use G53-G59:
As explained in this tutorial from cnccookbook.com
:
Basic work offsets are very simple to specify: simply enter one of G54, G55, G56, G57, G58, or G59. [...] When you execute the work offset g-code, the XYZ offset will be added to all of your coordinates from that point forward.
As detailed on Wikipedia
:
G54-59
: Have largely replaced position register (G50 and G92). Each tuple of axis offsets relates program zero directly to machine zero. Standard is 6 tuples (G54 to G59), with optional extensibility to 48 more via G54.1 P1 to P48.
And on the gcode dictionary provided by Hyrel 3D
:
G54 through G59 - Set Offsets
G54, G55, G56, G57, G58, and G59 will each store and invoke offsets in the X, Y, and/or Z axes for all subsequent moves. Any values not invoked will remain with their previous value (0 unless earlier specified otherwise).
X is the offset in mm in the X axis.
Y is the offset in mm in the Y axis.
Z is the offset in mm in the Z axis.
Here is an example:
```
G54 X100 Y-50
```
This command is decoded and executed by the printer as follows:
G54 (set offsets)
- X100 (+100mm to all X coordinates)
- Y-50 (-50mm to all Y coordinates)
Note that this differs from an M6, where the offsets are only applied to a SINGLE tool position.
Disclaimer: I work for Hyrel 3D.


Question:
Thermal conductivity is how well a plastic conducts heat. Most plastics don't conduct heat very well at all, which is what allows them to be 3D printed. That being said, there are a lot of potential use cases for highly thermally conductive filament, assuming you could print them. A commonly discussed one is computer heatsinks. Similar heatsinks could also be used for stepper motors and extruders in 3d printing.

To get a good picture which plastics are useful in such an application (like mentioned in question: "Water-cooling stepper motor with aluminum block"), I need to know what is the thermal conductivity of the commonly used thermoplastics.

Answer:
All values are in W/(m*K).
PLA: 0.13
HIPS: 0.20
ABS: 0.25
PETG: 0.29
PEEK: 0.25
PLA with copper: 0.25 (
see discussion
)
PETG with 40% graphite: 1.70 (ansiotropic)
TCPoly
: 15
Steel (not a 3dprintable plastic): 10 - 50


Question: Often, the pre-generated G-code is enough for start and end. However, sometimes we want to have something different. In this case: how to generate an audible alert of something like 4 bleeps at the end of the print, after putting the printer into the end position and when the bed has reached a "safe" 30 °C?

Answer:
Let's put the parts one by one:
Wait for bed temperature being at 30 °C:
```
M190 R30
```
Play Bleep for 1/5th of a second:
```
M300 S440 P200
```
Wait for 1/5th of a second:
```
G4 P200
```
That gives:
```
```
M190 R30
M140 S0
M300 S440 P200
G4 P200
M300 S440 P200
G4 P200
M300 S440 P200
G4 P200
M300 S440 P200
G4 P200
```
```
Just for 0scar:
```
```
M300 S1396.91 P400 ;f7
G4 P400
M300 S1661.22 P600 ;as7
M300 S1396.91 P400 ;f7
M300 S1396.91 P200 ;f7
M300 S1864.66 P400 ;b7
M300 S1244.51 P400 ;es7
M300 S1396.91 P400 ;f7
G4 P400
M300 S2093.00 P400 ;c8
M300 S1396.91 P400 ;f7
M300 S1396.91 P200 ;f7
M300 S2217.46 P400 ;des8
M300 S2093.00 P400 ;c8
M300 S1661.22 P400 ;as7
M300 S1396.91 P400 ;f7
M300 S2093.00 P400 ;c8
M300 S2793.83 P400 ;f8
M300 S1244.51 P400 ;es7
M300 S1244.51 P200 ;es7
M300 S1046.50 P400 ;c7
M300 S1567.98 P400 ;g7
M300 S1396.91 P1600 ;f7
```
```


Question:
Which of these will heat a bed fastest?

A. 12 V, 10 A power supply

B. 24 V, 5 A power supply

C. Both A and B will be the same (only total watts matter)

D. Depends on the situation

I originally thought Amperage was what mattered until I realized I needed a 24 V power supply to even heat my Lulzbot mini bed by one degree.

I know voltage is used to determine insulation thickness on wires. But thin wires with high current in them also get hot. Is insulation thickness on wires only to prevent you from accidentally cutting through them and shocking yourself, or is it for heat reasons?

I'd like to power my heated bed with a 19.5 V, 5 A power supply. It's just an old laptop charger - I want to reduce strain on my circuit. It's a big bed and I have a few other laptop chargers lying around so I'd prefer to choose the best one.

Answer:
It depends on whether you are re-using the bed or not, it is actually the resistance of the bed that determines this in conjunction with the voltage (the current you get for free).
Let's say that the heatbed resistance is 1.2 Ω (depending on the heated bed make and model the resistance is typically in between 0.9 - 1.5 Ω), this means that the power can be calculated using:
$$P = U \times I$$
$$U = I \times R$$
combining gives:
$$ P = I^2\times R = \frac{U^2}{R} $$
For 12 V (assumed default printer voltage) this means that the heatbed power equals about 120 Watt (at a current of 10 A). Running that same bed at 24 V means that the power is 480 Watt (at a current of 20 A). So yes, that will heat up fast, at the expense of an increased current, which is pretty high, and should not be attempted without extra resistance in the loop.
If you're using the laptop charger, the current draw equals about 16 A, which the adapter cannot deliver.
This means that you need to acquire a new heatbed that is able to handle a higher voltage out of the box (more resistance), or you need to put additional resistors in the loop, but beware of the currents. Note that heated beds for 12 V/24 V exist, the wiring is different depending on the voltage. Note that such beds heat up faster, it all depends on the resistance and the voltage, but running the 24 V circuit on 19.5 V (160 Watt bed) is definitely an improvement over the 120 Watt bed at 12 V but still requires about 8 A (only applicable to heatbed that can run 12 V/24 V through extra resistance connections).
Be careful with this and be sure what you are doing!


Question:
I have mounted two radial fan on my printer as a part cooling solution.

As you can see, the fan has input on the left side and blows air down. Does a mirror construction exists? With outlet on the right.

I can even print my own casing, but I'm not sure if the fan will work, if I change the rotation direction.

I'm using this print cooling fan duct: https://www.thingiverse.com/thing:1850163

The fan on the right side has the opening facing the hotend, and there is not much space, so the impeller can catch on wiring etc. If the right fan had opening to the right, there would be no such problem.

Answer:
https://www.alibaba.com/product-detail/120mm-Small-Squirrel-Cage-Exhaust-Plastic_653850349.html?spm=a2700.7724857.normalList.14.23834341IiKFAu&s=p
After quite a bit of searching the above link from Alibaba was all I could find. I suspect that they don't make them like that because of the direction of the rotation of the blades. Perhaps they are made so that the rotor can be swapped around if necessary.
(
https://i1.wp.com/www.homeintheearth.com/wp-content/uploads/2012/11/CentrifugalFanTypes.jpg
)
The different curving of the blades affects either the volume or the pressure of the airflow (or both).
Alternatively how about one that is more agnostic:
https://www.amazon.com/2Packs-Wathai-40x40x10mm-Brushless-Centrifugal/dp/B07RNZF97F/
Or just 3d print your own housing!


Question:
I recently installed a SKR 1.3 Board with a 3DTouch-Probe on my Creality Ender 3 Pro.
The probe works, G29 does its magic, but:

If i issue a plain G28, the hotend first homes X and Y like before the Z-probe.
The probe is now next to, not above, the bed.
As the next step, the printer is supposed to home the Z-axis. The probe deploys and Z starts to lower until it smashes into the bed, because the probe misses the bed (if I don't stop it, that is).

I configured X/Y offsets for the probe, but they don't seem to be honored when performing the G28 code.

If I home X/Y "manually" with G28 X Y, move the hotend with like G1 X45 Y10, then home Z with G28 Z it works fine.

What did I miss? Is this intended behaviour & the user has to take care never to issue a plain G28?!

Answer:
You need to enable the constant
```
Z_SAFE_HOMING
```
(like:
```
#define Z_SAFE_HOMING
```
) in your
printer configuration file
(if you're using Marlin firmware that is). This will move the nozzle to the middle of the plate prior to lowering the nozzle by default:
```
```
#if ENABLED(Z_SAFE_HOMING)
  #define Z_SAFE_HOMING_X_POINT ((X_BED_SIZE) / 2)    // X point for Z homing when homing all axes (G28).
  #define Z_SAFE_HOMING_Y_POINT ((Y_BED_SIZE) / 2)    // Y point for Z homing when homing all axes (G28).
#endif
```
```


Question:
I want to make Polyurethane molds for concrete using 3D printed PLA or ABS master object. like this video:

 (this video is not about concrete of course!)

I'm not sure if it will stick to PLA or ABS master or not! if it does stick, whick wax material can solve this problem... Do I need to print my masters with another filament?

Answer:
Temperature
As polyurethane cures (or hardens), it undergoes a chemical bonding reaction, linking the mono- and oligomer strings in the components into long polyurethane chains.
The chemical reaction is exothermic
, it creates heat.
So, we have a process that heats up the polyurethane mixture as it hardens, but how much? Well, it's hard to find numbers for it, but I suspect it can easily reach 30 to 40 °C, depending on the mixture (fast curing) it could easily go higher. To combat the effects of heat softening of the PLA/ABS model inside the mold, I strongly suggest printing with extra shells and extra infill. While most items can get away with 10 %, in this case, I suggest 20-30 %. ABS would be the superior choice above PLA as it starts to deform at a higher temperature. PLA can start to deform at around 60 °C, ABS only at about 80 °C.
The temperature of the PU curing depends on the speed of the curing process - it is safer for the masters to choose a slower curing mix as the heat is generated over a longer time and the maximum temperature is thus lower as a result (as excess heat is lost to the room)
Surface
To reduce the sticking to the surface from the material creeping into the gaps of the model, it has to be as smooth as possible and best also sealed. If you choose ABS, a quick acetone vapor bath would do the trick in this case. PLA should be lacquer sealed as it doesn't like to stick to most waxes.
Adding a mold release agent isn't necessarily needed, but could help in removing the masters from the mold.
Conclusion
ABS might be the better choice in this application. It is advisable to use extra-thick walls (3+), a lot of infill (20-30 %) and a vapor smoothed surface.


Question:
Is it possible with the accuracy of current 3D printers to print a sound trace?

On a vinyl record the grooves in the record are an encoded sound. Is something like this doable with 3D printers?

If Vinyl-like isn't possible, could a sound be printed at desktop scale? I mean printing the waves out that if you ran your finger along it it would reproduce the encoded sound? Examples would be Rumble Strips, the Musical Roads or highway rumble strips.

Answer:
Sound Encoding basics
Sound is a compression wave, and any depiction of it has to be an encoding of it. You can encode it so you can recreate the sound using a contraption that oscillates in the right way to compress air again in the right pattern, but you can't just "print it out" like you can scale up a lightwave from the nanometer scale to a visible one as a representation.
Let's take a simple example: a 440 Hz tune is generally considered to be the A
4
, aka
concert pitch a
or A440.
It could be encoded in a various ways. The probably oldest is to encode it as a note in violin notation, which then could be reproduced by anyone using a properly tuned instrument. The actual result depends on the instrument used as much as on the skill of the player. Each instrument thus might decode this encoded note differently, based on the physical setup of the instrument. Each instrument
automatically
creates the appropriate overtones.
In Midi, it is encoded as
```
Note 69
```
and any machine that can decode a midi file could use this instruction, paired with an instrument to use, to create the A
4
that is set for it. In Midi, the mere instruction of Note 69 does cut out skill, but how it sounds and feels comes from the instrument setup - which contains information about what overtones are to be created when playing this note.
For a physicist, the pure sound is encoded as just the notion of
```
440 Hz
```
and some amplitude to balance how loud it is. With those instructions, he'd be able to set up a device that has these creates a 440 Hz tune. To generate the sound and feel of an instrument, the encoding for a physicist would need to contain all the overtones that are to swing with this one sound.
History of sound recording
Let's look at the very first way of recording sound: The Phonautograph of 1857 used a piece of paper or a sheet of glass blackened and then a membrane move a needle. When the plate would be moved, the needle left a written path. The encoding was done via 2 factors: the setup of the stylus (mainly how long is the arm) and the speed of the movement of the plate. Changing either changed the encoding. A longer arm would record a larger amplitude (making fainter sounds recordable) while faster movement would alter the timescale recorded, allowing to look at short instances and better compare them.
These vibration-pattern records could be used to measure and compare sounds but not be used to recreate the sound, as lines on paper nor scratches in soot are a good way to keep a reading needle in boundaries. it took till 2000 and the use of scanners as well as digital processing to recreate these recorded sounds.
The solution to recreate sounds was found by the Edison Laps in 1877 with the phonograph, which used a piece of thick tinfoil to record the motion pattern of the membrane. Again, then encoding was done via the arm setup and the speed at which the tinfoil clad cylinder moved (or rather rotated). It would till the 1880s develop to a wax cylinder, which was easier to inscribe and reproduce from. One such machine was used by Carl Orff.
The first Gramophone came in 1889, mainly altering the shape of the recording medium from cylinders to the well-known shape of vinyl records but made from hard plastics and shellac. Around 1901, a 12-inch gramophone disk held only a 4 minutes track, speaking volumes about the problems of encoding the complex patterns of sound onto a disk. At the same time, an Edison Amberol Cylinder held 4 minutes 30 seconds but would spin at 160 rpm. Soon after, celluloid would become the recording medium of its time, and the disk the de-facto "standard" as it was much better storable.
In 1925 finally, a real standard was developed to record at around
$78^{+0.26}_{-0.08}$
rpm, which lead to only a 0.34 rpm difference between areas of 60 or 50 Hz mains voltage (though they needed different encoder rings), making records interchangeable between both machine types. All these recordings were encoded naturally: the vibrations of the membrane in the recording tool would be 1:1 transmitted to the vibrating stylus that would then do the encoding in such a way that a machine would reproduce what the recording one "heard" quite accurately.
When Vinyl came to the playing field as a recording medium at the end of world war II, so came a swap in the reading needle type: instead of a needle that would agitate a membrane directily, sapphire needles that would agitate an electrical pickup which in turn would activate a speaker. But while the recording technology advanced, the track length of a 12-inch disk was still limited to about 4 minutes at 78 rpm. It would only reach more than this in the last years of its use by applying LP technologies to pack the track tighter in the 1950s, achieving 17 minutes.
1948 came the LP, what we know as a classic vinyl record. At its introduction it could cram 23 minutes onto one side, making this possible by only using 33.5 rpm as the recording speed and thinner, much tighter coiled groves, increasing the information density by a factor of 5.75 for a 12-inch disk. 7-inch 45 rpm "singles" came out 4 years later. Within 10 years, the 33.5 and 45 rpm encoded variants had almost completely replaced the 78 rpm market.
Vinyl
As the history of analogous recordings shows, encoding a sound signal is rather easy in theory, hard in practice. A typical 12-inch
LP Vinyl record
of 20 minutes is a grove that is  427 meters long and coiled up 667 times. That means a single groove is between 0.04 and 0.08 mm wide - with an equally thin wall between. That means, that to achieve a printed phonograph record, you'd have to print accurately down to 40 microns to get an
empty
track. However, we also need to add the signal atop. And here comes the real problem:
An empty track has some 22 µm deviations, which the needle will usually not pick up at all. Dust, which creates the crackling at times, is in the same area (1-100 µm). The actual sound signal is encoded to have features as small as 75 nanometers. That is 3 magnitudes lower than the mere geometry of the grove, and equally much lower than any printer - including SLS - can achieve today, as 50 µm is often considered a lower limit in 2019.
To show how much tiny defects would ruin the sound quality, look at
this rapid cast
of a vinyl record. The resolution of the negative and the subsequently cast record is good enough to recognize the music, but the resin cast did contain so many gas bubbles that the noise level of the copy is very high.
Bonus: Unlike on cylinders the encoding of the signal on disks changes from the start to the end! The vinyl spins at a constant rate, but the radius from the center changes, leading in the speed on any part of the grove to be different as
$|v|=|\omega \vec r \sin(\theta)|$
, where omega is the speed in rad per second, theta is the angle of the reeding, so in this case, the sinus term becomes 1 and vanishes. This factor has to be taken into account for encoding so the pitch of the record doesn't change if the record is not created naturally by inscribing the signal onto a spinning disk.
Other encoding
Rumble Strips
However, it is quite easy to create a structure that creates sounds based on interaction with another body. Highway Sound Strips create sounds as the car tire bumps up and down, turning the car and tires into resonance bodies while the street "beats" upon it. In the case of a large percussion instrument like a car, we are talking centimeter scale.
Peg-Cylinder
A very simple method would be to go back to encoding and check out the note notation but limiting the length of notes to one unit. Encoding music this way results in pegs or ridges on a cylinder, which then can be used to actuate a mechanism to decode the music and create sounds like in a music box. In a music box of this kind, the demand for accuracy is about 3 to 5 magnitudes lower than in vinyl records: we speak about a tenth of a millimeter to centimeter scale.
Such a
Musical box
or
noisemaker
can be easily printed and is pretty much a rumble strip coiled around a cylinder. The length of the sample is determined by the resolution, playback speed and diameter of the cylinder while the complexity is determined by the rows of pegs of it: a noisemaker is pretty much a 1-note, high speed, music box. Typically, one rotation stores about 25 to 30 seconds. Typical examples would be the first part of
Für Elise
,  or the
Marble Machine
(Between second 30 and 35 the encoding wheel rotates 1 fifth). Some barrel organs also use the peg method, like one can
see here
. With some trickery, one cylinder could be used to encode multiple parts that play one after another once a rotation is done by and silencing some parts of the machine depending on an extra encoder, like
this 3-part
Für Elise
music box.
Hole-Plate(-strip)
A different method would be to encode the music as holes in a continuous strip and use air as a decoding method. If the air then gets directed into pipes, we have a street organ. Typically, one would use a paper strip as the encoded message, but it could be printed just as well, especially if one uses a setup that uses plates hinged to one another instead of a rolled-up paper as in
this example
. With such a way to stash away the extra length, the upper limit for music length rises from a couple of seconds to several minutes easily even with such a "bad" encoding.


Question:
I am printing using an Ender3 Pro with eSUN PLA+ 215/45 and I am getting this issue on two corners, the other two corners look fine.

Any idea on what can be causing this?

The bad corners

The good corners

Answer:
Looks like it treated those corners a bit differently in the slice routine.  Normally something like this different treatment would be too slight to matter, but (probably due to the slight overhang?) it appears to have caused some layers to not adhere to the bottom ones and get pulled along to a different shape (red line in image).  (Be sure to check some general layer adhesion/overhang topics too.)
I'd try increasing the infill there (and using honeycomb style infill) or even using a cad software to hollow the interior to essentially a desired infill before slicing if the current infill is important elsewhere.
Moving slower, Increasing the temperature a bit, and/or extruding more material per line and layer if the layer adhesion is due to the slight overhang (although it looks pretty small).


Question:
I'm using Cura to slice my prints. I've noticed that when printing the bottom layer (and also the top layer, if it's flat), it first prints three walls, then fills in the middle by moving back and forth in straight lines.

I've noticed that for my parts, the walls look much nicer than the zig-zag pattern in the middle, and it also seems that the zig-zag part detaches from the bed quite easily, whereas the walls don't.

My parts would look much better, and possibly also stick better to the bed, if I set the number of walls to 100 or so, so that the parts would be entirely filled in with walls. But then the parts would be completely solid, which isn't what I want. So what I want to achieve is that the bottom layer (and if possible also the top layer) are printed as if the part was composed entirely of walls, but the other layers are printed with three walls as normal. Is this possible in Cura?

Answer:
I found the answer myself just after posting - I'm posting it because it might be helpful to other Cura novices.
There is a setting for this, it's just that it's not shown by default. In print settings, you have to click on the three lines next to the search box, and select "Show All Settings". Then you can find a setting called "Top/Bottom Pattern". Setting this to "concentric" does what I described.
Actually this setting affects not just the top and bottom layers, but all layers that are part of the top and bottom shell. This seems like a good thing, but if you really want to affect
just
the bottom layer, there's a setting "Bottom Pattern Initial Layer" that does this. There is also a setting under "Experimental" called "Top Surface Skin Pattern" that I think does the same for just the top layer.
In addition to "Concentric" there is also a "Zig Zag" option that's quite similar to the default "Lines" mode.
You can also change the visibility of settings in the preferences menu, to make these settings show up by default.


Question:
I have made some prints with the Ultimaker 2+ and Ultimaker 2 Extended+. The prints are in PLA. For slicing, I use Cura and I check the support checkbox (haven't gone to advanced settings to adjust support yet). I can clearly see that there is a little space between the support and the print. The supports often look like long pillars and such.

My question then is: "What is the best technique for removing the support?". Is it to use a knife, pliers or perhaps PLA-water? Is it possible to use PLA-water to remove support when printed with Ulitmaker 2+ or is that just the Ultimaker 3? What type of technique would give a good looking print?

Ultimaker 3 has support filament that's water-soluble. Is there something similar for Ultimaker 2+?

Answer:
PLA and ABS are hard plastics. They are not water-soluble. If you print with these materials, just snap printed support materials off and clean the interface layer with a knife and sanding.
To remove the support, it is best to use strong tweezers or a pair of pliers to grip and then apply some force. Generally, I use needle pliers, but occasionally I also use snippets to cut up the support towers into more manageable chunks and keep the printed part safer. It can help to remove it in pieces and score the breaking lines.
As PLA is brittle, I prefer to break away from the object and not pull.


Question:
I have a Printrboard rev. D which includes Allegro A4982 drivers. I would like to replace them, but it appears that newer TMC drivers all require several pins for proper operation.

How can I upgrade the drivers in the Printrboard rev. D?

Answer:
You can't. In fact, pretty much all boards with directly soldered drivers are not upgradable.
I'd recommend to buy a proper, contemporary, customizable board like the SKR 1.3 for TMCs.
The Fysetc F6 would also work, but uses "custom" connectors and is still AVR based.


Question:
So while doing some research I stumbled upon a wiki page on reprap from a few years back where the user was creating a glass nozzle to replace the brass and PTFE assembly.1

Does anyone know the theory behind this? Glass is a great insulator so I could see how that would be beneficial for the heat break part but I can't see how it is appropriate for the nozzle as this is normally brass which is a good conductor.

Surely the glass takes much more energy to heat up?

On a side note I've seen similar projects using ceramic instead.

Answer:
Ceramic I can understand - very strong, great thermal range capability.  Glass not so much - you'd need some seriously careful annealing at least.
In either case the material is much harder than brass, or even steel, so you could presumably use tougher tools to unclog, etc. as needed.  If you're using materials loaded with wood or metallic particles, the glass/ceramic tip will be less likely to degrade than brass.
BTW, glass being a thermal insulator means it may take
longer
to heat up, but the
energy
required is probably less . The specific heat of glass is on the order of .84 J/gm-K . Compare with brass at  0.38 , but keep in mind the rate at which brass will shed heat into the air vs. glass.  In either case the energy is tiny compared with the thermal mass of the hotend assembly.


Question: I recently got a Creality Ender-3, and tried printing a few things for some tests. I’ve printed a cube and just printed a cylindrical tube today, and I notice each time, it adds this random line on the left and a sort of outline around the actual print. Neither of these were there in my Cura file, but they’re always printed and I’m not sure why?

Answer:
The outline around the actual print is called
Skirts
. and the random line on the left is called
intro line
it's not necessary you need both Skirt and intro line. The intro line can disable from custom starting gcode settings
A skirt is an outline that surrounds your part but does not touch the part.
The skirt is extruded on the print bed before starting to print your model. Skirts serve a useful purpose because they help
prime your extruder and establish a smooth flow of filament
.  Observing the skirt also allows you to
detect and adjust any leveling or adhesion issues
before the actual model begins printing.
You can easily edit/disable(not recommended) those settings in Cura (or in any slicing software)
In you Cura navigate to
Build Plate Adhesion
settings
Skirt line count:
The number of skirt lines printed around the model.
Skirt distance:
The distance between the model and the skirt.
Skirt minimum length:
The total length of the skirt. This will
override the skirt line count when the minimum length is not reached
yet.


Question:
According to the instructions I have read, you use the same output on the printers mainboard to control a 110 V heated bed with a solid state relay, as you do to power the 12/24 V heated bed that comes with the printer.

The relay's datasheet states that its max input current is 25 mA, obviously a 12/24 V heated bed would draw a lot more than that.

How does Marlin know that the heated bed pins are controlling a relay now instead of a bed directly, and therefore should limit their current output?

In other words: I am worried that if I just drop in the relay, it will burn up since the board still thinks it needs to supply high current to the bed.

Answer:
There are two current parameters which you are looking at in your instructions for the solid state relay. The first one (the 25mA) is for the
control
circuit. This is how much amperage the device itself will draw when in operation. The second is for the
load
circuit. This is the max amperage which can pass through the device.
Your
instruction sheet
shows the device having the ability to work at 10A, 15A, 20A, 25A, or 40A. These are different ratings for the same style of device. When you purchase the device, you'd need to specify which amperage rating you'd want your device to be at. They use the same spec sheet for all five flavors, because they are basically the same thing with the one exception, which is the amp rating.


Question: I am trying to increase the flow rate on my Ender 3 from 100 to 108 % but every time I start a new print it reverts back to the old 100 % flow rate. I have clicked through the settings and pressed the "store settings" button but it still reverts back at the start of every print. I don't want to do this in my slicer settings as I run 18 Ender 3's so I want to be able to use the same G-code for each.

Answer:
Changing the
flow rate
during a print can
not
be saved. There simply is no way. It is usually meant to be a fix with filament inconsistencies or to look for the right extrusion factor for a new filament batch.
Slicer
The only way to consistently increase the flow rate would be  to alter the
```
flow rate
```
in your slicer to what you have found to work best for each machine, probably using separate profiles. This will up the rate for every subsequently sliced print. Note though that this 108 % increased extrusion is converted extrusion factors that are simply numerical and 1.08 times the normal in the g-code. These numerical values will be taken as 100 % by the printer - and since it requires extra work to slice the gode for different profiles it is not the optimal solution.
As you elaborated though, this is not a doable thing, so let's look further.
Source hunt & Workaround
Since only one printer is showing underextrusion while the others do not, it is time to check the hard- and firmware:
underextrusion can be caused by a defective extruder assembly or a damaged or blocked nozzle.
if a machine has consistent underextrusion, its steps/mm in the firmware might be off. This could be altered and stored in the EEPROM. Since this could be a machine unique setting, here would be your point of attack to increase the extrusion of just one machine while using the identical G-code to all other machines.
Note that the standard firmware of the Ender-3 in 2019 did not contain Thermal Runaway Protection (
What is Thermal Runaway Protection?
) and should be upgraded because of this anyway. You have to flash a bootloader too, so in the process of doing the upgradeability and safety-upgrade to all the machines, you could store the altered steps/mm to each machine individually so they get consistent output.


Question:
I understand the principle of why a heater block is used. Helping to reduce temperature variation as the filament is extruded using the heat capacity of the block.

But I’m wondering why it takes the form it does? I imagine it is cuboid in shape just for convenience as it’s easy to machine?

From a surface area to volume ratio a cuboid appears to be one of the worst shapes to use.

Note:
I am currently doing a project which requires me to increase the tool clearance of the nozzle of a 3D printer. Hence why I am exploring alternative print head configurations and heater block design trying to minimise the profile of the print head as much as possible.

Answer:
Changing the
flow rate
during a print can
not
be saved. There simply is no way. It is usually meant to be a fix with filament inconsistencies or to look for the right extrusion factor for a new filament batch.
Slicer
The only way to consistently increase the flow rate would be  to alter the
```
flow rate
```
in your slicer to what you have found to work best for each machine, probably using separate profiles. This will up the rate for every subsequently sliced print. Note though that this 108 % increased extrusion is converted extrusion factors that are simply numerical and 1.08 times the normal in the g-code. These numerical values will be taken as 100 % by the printer - and since it requires extra work to slice the gode for different profiles it is not the optimal solution.
As you elaborated though, this is not a doable thing, so let's look further.
Source hunt & Workaround
Since only one printer is showing underextrusion while the others do not, it is time to check the hard- and firmware:
underextrusion can be caused by a defective extruder assembly or a damaged or blocked nozzle.
if a machine has consistent underextrusion, its steps/mm in the firmware might be off. This could be altered and stored in the EEPROM. Since this could be a machine unique setting, here would be your point of attack to increase the extrusion of just one machine while using the identical G-code to all other machines.
Note that the standard firmware of the Ender-3 in 2019 did not contain Thermal Runaway Protection (
What is Thermal Runaway Protection?
) and should be upgraded because of this anyway. You have to flash a bootloader too, so in the process of doing the upgradeability and safety-upgrade to all the machines, you could store the altered steps/mm to each machine individually so they get consistent output.


Question:
I just order myself an Ender 3 Pro which will come by the end of the week.
Before it arrives I want to be ready to flash a bootloader onto it.

I was wondering what other options there are to flashing except using an Arduino?

I have a bunch of ESP8266/ESP32 and a USB to TTL. Would it be possible to use these somehow instead of an Arduino to flash a bootloader to the Ender 3?
Or should I just go buy an Arduino?

Answer:
What you need to is called a ICSP or ISP:
in-circuit serial programmer or in-system programmer
, which excludes the USB to TTL device you own.
I've never used an ESP8266 as ICSP but it seems there are
some resources out there
reporting it is possible.
If you want to go the easiest way probably you want to buy an Arduino and follow the tons of tutorials out there, if you are looking to save some money then you might get around buying an ICSP like the very well known USBASP (just Google for that).


Question:
I know that M73 P19 means "Set completion progress to 19%", and I suspect that M73 R42 means "Set remaining time to 42 minutes", but what is M73 Q17 S43? I can't find description of such syntax.

The command is seen in .gcode files produced by PrusaSlicer.

Answer:
The tooltip for "Supports remaining times" under
```
Printer Settings -> General -> Firmware
```
in PrusaSlicer quotes:
```
```
Emit M73 P[percent printed] R[remaining time in minutes] at 1 minute intervals
into the G-code to let the firmware show accurate remaining time.
As of now only the Prusa i3 MK3 firmware recognizes M73.
Also the i3 MK3 firmware supports M73 Qxx Sxx for the silent mode.
```
```
Therefore:
P = Percentage printed, normal mode
R = Remaining time, normal mode
Q = Percentage printed, silent mode
S = Remaining time, silent mode


Question:
Is there a classification of method of control most (FDM) 3D printers fall under?

From a 1986robotics textbookref I was reading they defined three classes of control:

1) Pick and place

2) Point to point

3) Continuous path

However, both point to point and continuous path control are stated as requiring servo motors.

I know that the majority of 3D printers are actuated with stepper motors as opposed to servo. Does the continuous path classification still apply? Or is there another classification?

ref - Todd, D.J.(Ed.):Fundamentals of Robot Technology: An Introduction to Industrial Robots, Teleoperators and Robot Vehicles - Kogan Page 1986

Answer:
The question is if robots classification terminology the textbook sketches applies to 3D printing?
Servos (closed loop) are used in robots to guarantee position (you don't want to accumulate an error after repetitive movement), most 3D printers use open loop steppers that are instructed on a point to point basis through G-code instructions, implying that the use of servos is not a "requirement" for point to point control.
It
is
a requirement if you want to be absolutely sure that the position is reached. In 3D printing where the loads are generally low, this requirement is frequently dropped. But, there are printers that use servo control.
Note that many CNC machines (operating at much higher loads than a 3D printer) even don't use servo's but (open loop) steppers, these are generally larger and more powerful (more torque).


Question:
How can I correctly clean the lacquer from bed printer?

I have used some ethylic alcohol (ethanol) to help cleaning

But what is the best way to do it?

Answer:
The Ender 3 does not come with a lacquered surface at all.The bed should have a rough build surface that is a clone of the BuildTak build surface. It is
intended
to be rough and satin-gloss in its native state. I do not remember if there was a thin protective plastic foil on my Ender-3 bed on delivery, but if there was, it should have been removed during assembly.
A BuildTak surface can be easily cleaned with isopropyl or ethyl alcohol of grease and fingerprints. The odd discoloration at the edges seems to be a layer of grease and dust, which can be easily cleaned away by soaking it in Isopropyl alcohol and then wiped with a microfiber cloth.
If the bed surface is destroyed by chipping holes into it, sanding it or otherwise ruining it (like melting plastic rap into it), you will need to replace it. Replacement surfaces come about 5 bucks on Amazon. Doing this, you might find
How to clean up my buildpate for a new build surface?
helpful.


Question:
I switched my Anet A8 over to a Bowden and it's printing great. Moving that weight off has enabled me to almost double the speed and resonance problems have vanished.

My question is regarding after the print is done should I add a retraction code and back the filament out of the v6 or is it okay to leave it in there?

My concern is that if I leave it in there, will it cause a clog or anything when I warm up the printer tomorrow to print something else? If that's not a something I should be concerned about let me know.

Answer:
It's okay to leave the filament in the hot end, as long as you let it cool down with the hot end cooling fan running.
From comment:
That's not an issue, you can simply leave it in the hot end. The only "end of print" clogs usually occur when leaving the hot end hot for a while - allowing the filament to drip out - and then retract the filament without feeding it against the nozzle once more. That creates a plug that's larger than the filament diameter that might get stuck in the bowden tube


Question:
From the M502 documentation page can be read that M502:

Reset all configurable settings to their factory defaults.

Please note that this phrasing from the manual has been used in the question title!

To also reset settings in EEPROM, follow with M500.

Note that:

This command can be used even if EEPROM_SETTINGS is disabled.

The question is what is the definition of "all configurable settings"?

Are these the settings that are displayed with M503, or are there hidden settings?

Answer:
What Marlin does when
```
M502
```
is called is defined in the
```
configuration_store.cpp
```
file.
It resets:
Max acceleration
Steps per mm
Max feedrate / speed
Min segment time
Acceleration (Normal, Retract, Travel)
Min feedrate
Min travel feedrate
Jerk settings
Junction deviation
Home and SCARA offsets
Hot end offsets
Filament runout sensor distance
Tool change parameters (Swap length, extra prime, prime speed, retract speed, Park
positions, Z raise)
Backlash correction distances and smoothing parameters
Extensible UI
Magnetic parking extruder settings
ABL (fade height, stored points, nozzle offset, servo angles
Delta calibration data (Height, Endstop offset, radius, rod length, segments per
second, calibration radius, trim angle)
Dual / triple endstop adjustments
Preheat parameters
PID parameters
self-defined thermistors
LCD contrast
Power loss recovery
Firmware retraction
Filament diameter (for volumetric extrusion)
Endstops (if disabled)
Stepper drivers
Linear advance parameters
Motor currents (digipot)
CNC coordinate system (if selected)
Skew correction parameters
Advance pause filament change lengths


Question:
I'm new to 3D printing. I've made some projects before just fine, but this project is giving me problems.

I 3D printed a trumpet mouthpiece, and the printer made supports inside the mouthpiece funnel. I can easily remove the exterior supports, but I don't know how to get to the supports inside. Does anyone know how I would do that?

Here is the link to the model

Answer:
Based on the photo provided, there's a strong possibility that you can print that model without internal supports. The angle of the walls falls within the limits of just about any FDM/FFF printer. An exception to this would be if you had a structure internal to the cone of the mouth piece which needed support.
ERROR: I neglected to note that your print is created "laying down" rather than vertically. This certainly complicates the printing/support problem. I typically print cylinders without internal support, although it does result in a small amount of droopies within the cylinder. Those are easily cleared away as required and much more easily than a full support forest.
Is it impractical for you to consider to cut the model in half, print both segments, remove the supports more easily, then glue them together?


Question: I'm designing a mount for a cylindrical speaker to attach to my bicycle. It will mount on the bottle cages. I've printed a few iterations with various infill settings (using PLA) and the weak point is always the bolts holding the entire mount to the bike. They can't handle the compression needed to secure it properly. I had thought about using an imbedded metal part to distribute the load, but it's not easily replicable and I want to make the design public and fairly accessible to others with the same speaker. I currently have PETG and ABS, would one of those perform better or should I order a specialty high strength polymer?

Answer: Try heating op your PLA while mounting it. The PLA wil temporarily weaken and will become a bit moldable. PETG is a bit more brittle than PLA is my experience so I'd say stick to PLA. Otherwise you might try Arnitel ECO. I can try to find an amazon purchase link for you if you want. Anyway, it is more rubber like and stays flexible, it will never crack but depending on your design it might become a bit more wobbly. If you share a picture of your design or an STL i might be able to help you a bit better.


Question: I want to make a project involving many small dots indents and I would like to know how I can calculate the smallest dot hole the Prusa i3 MK3S can extrude around on a layer using PLA. In other words, if I printer a mesh with circle shaped holes, how would I know the minimum diameter of the holes. Is it simply the same as the layer resolution (0.35 mm), filament size (1.75 mm), or is it something else?

Answer:
That depends on the ability how fast you get filament to stick to the build plate and whether the filament is loaded in the extruder. It also matters which size of nozzle you are using. The filament diameter has no influence other than smaller filament width (e.g. 1.75 mm) requires more length to extrude with respect to thicker filament (e.g 2.85 or 3.0 mm), and is therefore more precise to lay down (on the other side is the deviation on the filament diameter, i.e. manufacturing tolerance, larger than for thicker filament...).
If it does not stick you need more length, also, if the filament is not preloaded enough, the nozzle chamber needs to be filled first. Note that the printing of several small circles is a challenge, see e.g.
"How do I get circles on small interior holes to adhere to the bed?"
.


Question: I am printing minis and other very detailes stuff and I find that 0.04 mm layer height gives the best looking (smoothest) result. However it takes a long time, so I am looking for ways to speed it up. Is there any slicer which offers different layer heights for the outer perimiter? So you can print your model at 0.12 mm or so, but the outer layer gets printer first 3 times at 0.04 mm?

Answer:
In Ultimaker Cura, unless you print a single perimeter outline and add extra wall infill support you are not going to have different outer perimeter layer heights.
However, Cura is able to reduce the printing time, E.g. you can have fine layers for the wall (all perimeters), and coarse layers for the infill. The option is called
"Infill Layer Thickness"
:
Infill layer thickness
Since the layer height of the infill is not important for visual quality, you can use thicker layers on the infill to reduce the print time. When adjusting this setting, always make sure that it is a multiple of the layer height, otherwise Ultimaker Cura will round it up to a multiple of the layer height. This means that you can, for example, print with an infill thickness of 0.2 mm while the layer height is 0.1 mm. The printer will first print the walls for two layers, and then it will print one thicker infill layer.
Note that this is not a standard option, you need to put Cura in the "Custom" mode and filter/search for the option using the search bar. Below you'll find the upper right corner of the Cura Graphical User Interface where I searched for the option:
Note that there are 2 options, one for regular infill of your product and one for infill of the support structures.
An other department at work is working together with a start-up university company to 3D print PEEK molds (from pellets) using 2 nozzles/extruders (to create resin injection parts), one has a large nozzle, the other has a fine nozzle. They use their own developed slicer software to use the fine nozzle for the outer contours and the coarse nozzle for infill and support. It could be that they developed this because it was not available in commercial slicers. For the 2 most common free slicers, Cura and Slic3r, there is no option to have just the outer perimeter of different height than the inner perimeters. If you think of it, it is also pretty difficult to execute, you either get:
(which does not improve the quality of the product, it will make the outside more coarse) or you'll get gaps:
Note that both upper images do not include infill, only 1 outer and 3 inner perimeters. The image below is probably what is possible with Cura, so all perimeters the same; green is infill now:


Question:
Here is the context

I've got an old car for which I have a small plastic piece who is broken. As it's an old car and a very specific piece, I can't find it anymore. So I was thinking about 3D printing it.

My problem is this piece is on the carburetor, so close to the engine. This means, it can heat a lot, close to 90-100 °C.

My question

Do the pieces created with the common 3D printing techniques melt at 100 °C? If yes, what kind of other 3D printing technique can I use?

Here is the piece I want to recreate (sorry for the bad quality), the scale is in cm.

Answer:
Depending on the exact mechanical load and material used to print, you might get away with 100 °C.
Next to the melting temperature required to print the material (which will always be substantially higher than the maximum useable temperature!), you probably also want to have a look at the glass temperature of your specific material. Around that temperature your material becomes soft (rubber like) and can deform permanently when cooling down again. Chances exist that under a considerable mechanical load, the part will deform at even lower temperatures.
Maybe it would help to post a picture or describe the exact component you're trying to replicate. It might help in finding an alternative solution. (E.g. carving out of say PEEK to say anything.)


Question:
I'm printing with a Prusa MK3, with the following settings:

3 perimeters

50 % infill

infill overlap: 50 %

The filament is Polyalchemy emerald green (PLA). Nozzle temperature: 210 °C.

On a simple part (it's a keychain), the shell detaches if I apply a bit of force on a zone of the part that is "fragile". See picture. You might not be able to see it, but only the 2 external perimeters detach from the rest of the part. I used to print this part on another printer, and I never observed this problem.

Any idea on how to solve this problem? It seems the 3 external perimeters didn't fuse properly.

Answer:
I am looking at your picture, and I realize that it is not only that the perimeter is detaching from the infill, but also that the perimeter is breaking.
Once the perimeter breaks, the weaker connection with the infill will surely break, too.
You could try:
Using more than two perimeter layers.  Go big. Try five.
Add a fillet where the ring attaches so that the force is not focused on a point.
Choose an infill percentage and pattern that maximizes the contact between the perimeter and the body.
Change the angle on the bed at which the keychain is printed so that the infill maximally connects with the breaking point.  That might make the ring be 45 degrees off the X and Y axes.


Question:
I’ve just brought my printer back out after a month and it’s first print created a solid block of resin about 1.5 cm deep and the full width and length of the print bed. What could cause this?

My only thought so far is that the FEP film / vat bed is looking a little cloudy even after cleaning. I wondered if this could have caused the light to diffuse across the whole bed?

Answer:
Is the laser (or whatever light source it uses) visible? The cloudy film sounds like a good candidate for light diffusion and thus solidifying the entire resin, but if there are visible components to the light source it may help narrow it down.
If it uses a projector ("LCD") solutions, it may also be that the display that filters the light to certain regions of the resin to selectively solidify the print may be at fault, but that's rather unlikely.
The first thing that, in my
opinion
, you should do is to check that the object you are printing does not have a corrupt model file. Assuming that you have spare, fresh resin (if your resin is old, that's actually the most likely issue...) and it wasn't too hard to pry out that block, you could try printing something else that worked in the past.
While it's doing that, you may be able to see where/how it is printing. If the beam diffuses or lights up the whole area, you can tell if it's a printer issue (the film sounds like a good first thing to try replacing in that case). On the other hand, if the resin is old, it's probably just getting oversensitive and your printer is fine.
The resin is very touchy with these things, and has a shelf life of a few weeks to a few months, and less if it's ever opened.


Question:
I bought an Ender 3 two days ago and assembled it today. I think I did it properly, tested the movement of all axes which works for all axes. Then I performed the calibration as described in the manual. I used a piece of paper and adjusted the bed until it barely fits underneath the nozzle for all four corners. Afterwards, I wanted to print my first model so I selected the cat from the usb stick which came with printer. And now comes my problem. I let the printer run for 15 minutes. It moved and moved and moved but there was no filament on the bed. The nozzle and bed were heated properly. The one thing which I noticed was that the stepper which feeds the filament turns for like 30° and then flips back: to me it looks like the filament can not be fed in. After canceling the print the extruder moves back to the home position which is like 5 mm off the bed and then suddenly the filament flows out of the nozzle.

What part of the configuration I'm missing?

Answer: I use Cura on my Anycubic Chiron which I encountered a similar problem with and I was able to resolve the issue by preheating the nozzle to a higher temp. I would test the nozzle and make sure it is feeding properly. What I mean by that is load the filament manually and make sure it comes out. Reason I say this is because the other issue you may be running into is either the nozzle is clogged or it may be too close to the bed for it to come out of the nozzle. This is all speculation but hopefully it helps.


Question:
I printed a model and now I can't remove it.

I have been chiselling away with a putty knife and made little or no progress.  I even heated the bed up to 70 °C.  That really didn't seem to help.

Last time, I put it in vice, and tried to free it that way, but instead I broke the glass.

Suggestion?

Answer:
It's useful to know what material you used for the print. Also, you've referenced the glass that broke in the vise, which implies a glass bed, but did you use any adhesive spray or other application?
Allowing for all of this unknown information, there may be a solution for your release. Our library makerspace has a small bottle of 50-50 water/denatured alcohol, although isopropyl alcohol should also work if your glass is not coated with a special film such as PEI. Heat up the surface of the glass to your usual temperature (50-60°C) and apply a few drops of the mixture to the edge of the print.
It will evaporate pretty quickly, but some of it will work under the glass/model interface. Apply a bit more while the glass is still warm. Continue to apply until the the evaporation is no longer accelerated.
Considering the difficulty you are experiencing, it may be necessary to repeat the heating sequence multiple times in order to get enough wicking of the liquid to effect a release.


Question:
I've just built my first 3D printer. It uses a Bowden setup.

When I try to print the extruder starts fine, but after a few seconds the extruder motor start skipping and the nozzle is jammed.

I tried a cold pull, but it didn't help. I removed the PTFE tube and tried to push the filament with my hand, it works but at the start I need the push harder but after it flows fine. But if I reinstall the Bowden setup, it works fine for a few minutes, but after a few seconds it starts again.

Note I am using silver PLA at 200-205 °C. I tried to raise the temperature to 215 °C, but it also jammed, and the filament what after I pushed out was black (it is a new hotend and I never used black filament before), like it was burned (if it is possible).

Answer:
It is useful to diagnose your problem if you provide more information, specifically what material you are using and what temperature you are using on your hot end.
Even without the above information, it is likely that the hot end temperature is too low. At a low setting, the filament in the nozzle will soften, perhaps even melt as deeply as needed to be extruded, but as new filament is provided by the extruder motor, it also cools the heater block.
By increasing the temperature, you're ensuring there is sufficient thermal energy to handle the incoming cold material.
It would be useful to increase your nozzle temperature by 5°C for each test. Despite matching your controller's temperature to the manufacturer's specification, you can not be certain that the temperature at the nozzle and heat block are what you have programmed.


Question: I'm getting wavy lines on the first layer only in both the x and y direction identically.  The first layer is 0.4 mm with a 0.4 mm tip. The other layers are 0.2 mm.  I've tried changing the Z offset all the way from -1.2 to 0.5 mm.  I've tried changing the hot end leveling the heated bed.  None of these changes affected the wavy lines.  The waves have about a 1 mm period.  The printer is a German RipRap.  The material is ABS.  The heated bed is 110 °C.  I've tried the hot end at 220 °C and 240 °C.  So far, nothing has changed the waves.

Answer:
The general recommendation for layer height is to go no thicker than 75% of the nozzle diameter. Your post states 0.4 mm layer height with a 0.4 nozzle, exceeding the recommendation.
If your first layer is dropped to 0.3 mm, you'll fall into the recommendation, but the thickness is a reference for ALL layers.


Question: I have made a temperature ⨉ fan speed tower which needed 3x9-1 ChangeAtZ post processing scripts and it took me quite much time to configure them all (and check it twice). Is there a way to save this, so that I wouldn't need to make them all again if something went wrong and I needed to start over or if I wanted to do something similar again ?

Answer:
The UK uses 230 V mains voltage. The 220 V designation is from the past, Europe is now using 230 V. You do not have to worry about the frequency.
You should place the switch to 220 V and plug the cord into the socket. The printer should start immediately booting (cycling) the printer firmware, the LCD should light up and the cold end cooling fan will spin (annoyingly).
If nothing happens, you need to check the Power Supply Unit (PSU) and all cables for proper connection (does the fan of the PSU spin if it has one, you should at least see a led light up). A multimeter is not expensive and generally very valuable to test if it outputs 12 V. That way you know the PSU is working or not, if it works the problem is at the main printer board.
As these PSU's are pretty cheap and faulty, you could well have received a broken one.
How to measure the voltage?
If you look at the connection terminals you will find labels above them. Measuring position 6 and 8 might be the incorrect ones, this depends on your PSU. If you have exactly the same PSU as from the linked video, measuring between 6 and 8 would be correct:
From the image above the connections from left to right (for other PSU units, the order may be different, I have units where the connection to the mains is on the right):
```
L
```
,
```
N
```
and
```
ground
```
are used for connection to the mains,
```
COM
```
(stands for common or 0 V) or sometimes denoted as
```
-V
```
is the output ground (negative, connection for the black wires) and
```
+V
```
is positive, connection for the red wires.
You need to measure the voltage difference over
```
COM
```
and
```
+V
```
, this should be the voltage of the power supply. Ideally you measure the voltage when the power supply is delivering a load (e.g. directly connected to a strip of LEDs or directly connected to the heated bed; some faulty PSU crash in under load, this can be seen by a lower voltage than the rated voltage).
If the PSU is correctly wired, your fuse is not broken, does not have a LED lighted and the voltage is zero the unit is defective.


Question: I want to create two piece labels for storage containers. The main piece would be the “badge” which would have text cut out of it (e.g. “Paint”, “Electrical” etc.). The second piece would be a positive of the text which is would be in a different colour, and would fit inside the cut out on the badge. Because of the tolerance of 3D printers, I need to make the insert slightly smaller than the cut out. Initially, I thought I could just scale the insert but that would affect the letter spacing. Then I thought it would work if I could somehow taper the letters so they are slightly smaller at the top than the bottom. So my question is, how I do that. I did the original in OpenScad but I would try Fusion360 if that’s a better solution. Any and all suggestions are welcome. Thanks.

Answer:
In OpenSCAD, apply the
```
offset
```
transformation to inset the letter outlines before extruding them. However you may find it works better to fill the sunken letter shapes with nail polish then remove the overflow with acetone; see my question & answer
https://3dprinting.stackexchange.com/a/10872/11157
.