Question:
I realize this issue (warping) has been repeatedly addressed on this site. I've just graduated to high-temp filaments (PC in particular). I don't know much of the physics of this. I'm wondering whether the degree to which the filament contracts is proportional to the amount that it cools. If the answer is yes, then wouldn't it suggest that a lower printing temperature might reduce warping-as the temperature interval over which the filament cools is smaller? Or perhaps the difference is negligible?

Also, I see a lot of emphasis placed on good first layer adhesion. Is this still an issue if you are printing on a raft?

Answer:
I can't address polycarbonate specifically, but can provide a general overview of the higher temperature filament considerations.
Printing on a raft means that the adhesion temperature of the filament is accomplished. This temperature is the factor to be considered if you are thinking of dropping the printing temperature. If you drop below recommended minimums, you risk losing adhesion to the build plate and also inter-layer bonding. That alone means one should use caution when dropping printing temperatures.
Printing with a raft usually means the model's individual parts have such a small footprint that they would not remain bonded to the build plate. Rafts are also used on printers with an uncertain planar surface or irregularities in the surface. That's not applicable to this question, generally speaking.
Your question about contraction being proportional to the amount of cooling is perhaps misdirected. One could consider that the printing temperature is a manufacturer specified value and the cooled temperature would be generally considered room temperature. Room temperature would be addressed as a range, rather than a single value, but even as a range, there isn't going to be a big percentage of variation in the calculation involving the print temp/room temp.
My experience with the higher temperatures is more related to the volume of material per cross section (in all three dimensions). A printed model of substantial height with a relatively small horizontal cross section (think cylinder) is likely to have much less distortion in the x/y plane and greater distortion along the z-axis. The mass of filament cooling in the z-direction generates greater force than the smaller mass on the x/y axes.
Another factor in such thought processes is that layers are on the x/y axes and the strength of the extruded plastic is more homogeneous through the nozzle, while the z-direction creates inter-layer discontinuities, making warping and delamination easier.
I've found that I can reduce (but not eliminate) warping and delamination if I am able to maintain chamber temperature for longer periods and reduce temperature slowly. Unfortunately, I have a semi-enclosed printer and the heat loss is dependent partly on the ambient air temperature. A fully enclosed heated printer with auxiliary heating under some form of control may give you the best results.


Question:
That's my first 3d printer. I'm using Repetier Host as the brand recomends, and set all the configuration as the recommended one. I decided to print one STL file but the result is not the best one.
That's what I was trying to print:

and that's what I've got.

Here you have a video of the impression. it is a G2S pro rostock mini

Answer:
From the video it is very clear there is
a major problem with bed adhesion
.
It also looks like you are printing on bare metal (aluminium?) which I never saw anybody doing. I must admit I don't know it is impossible or simply very rare, but the first thing I would try in your case is
covering the bed in painter's tape
and wipe it with some alcohol
.  This is a surefire method to get good adhesion with PLA, which - from the temperatures shown in the video I assume is what you are using.
If you haven't tried this before, you should know that:
some brands of tape work well even without being wiped with alcohol
you may need to readjust your nozzle height after having applied the tape
Unless you have already done this, I would also suggest to print some
test cubes
and possibly some
stress tests
as your first prints, in order to check that the basics (extrusion rate, dimensional accuracy...) are working correctly, as well as getting familiar with the limitats of your printer.


Question: I was wondering if adding (an) extra fan(s) (not connected to the printer, but blowing on the print area) could improve the quality of PLA based prints(printing at 210 C). The printer already has a built in fan with a fan shroud that directs air to the hotend, but is it beneficial to add an extra fan in order to get better results on overhangs, fine details, etc, or does extra cooling negatively/not affect print quality?

Answer:
The printer already has a built in fan with a fan shroud that directs air to the hotend
Unless your printer is defective, it may look like so, but the airflow should really be directed towards the print, not the hot-end
.  Cooling the hot-end will at best just waste energy, requiring extra heat to keep it hot, at worst affect your print quality negatively.
is it beneficial to add an extra fan in order to get better results on overhangs?
The issue with external fans, not connected to the printer, is that you can't properly direct their ariflow, so:
you
will
direct some of it on the hot-end itself (see above on why that's not good)
you will potentially cool your print unevenly, which - depending from how much, how fast, and what type of filament you are using - may warp your prints
That said, depending from a number of factors, including your ability to position the fans appropriately,
you
may
gain some benefit from them (I saw people doing this to help with PETG stringing), but I would recommend instead to upgrade the part fan of your printer (e.g.: larger diameter, higher RPM) and your duct (better focus on the extruded filament)
, as these upgrades will have no drawbacks and will perform consistently on each part of the print.
For most common printer, there are printable mods that allow to do both, often available off thingiverse or on dedicated user community forums.


Question:
I had a problem with my nozzle on my homemade printer. The problem was that the nozzle with a 0.4 mm diameter wasn't putting out any plastic. I replaced the nozzle with a 0.2 mm one and now the bottom of my model is looking like this:
I tried to change flow,temperatures and speed.
But nothing helped it keeps making this waves. At the old 0.4 mm nozzle there everything was okay.

Answer:
Without more detail is difficult to say with certainty what the
root
cause of the problem is, but it looks like
too much material is being deposited on the bed
.
A few things to try/check:
Make sure the nozzle is not leaking
.  If it is, you should see fused plastic coming out from the seal nozzle/hot-end and/or hot-end/heat break and trickling down.  This is often the case when the nozzle hasn't been tightened enough, or it has been changed with the hot-end being cold, or if the internal PTFE tube has been dislodged upwards (does not apply to all-metal hot-ends).
Make sure you changed the appropriate setting for the nozzle diameter
.  This is
not
"flow" it is a separate setting.  If you haven't, your printer is now extruding ~4 times as much filament as it ought.
Recalibrate your nozzle height
.  This should be done at each nozzle change, as each nozzle is slightly different from the other, and it is possible your new nozzle now sits too close to the bed.
EDIT
: also, the picture is too low-res to be sure, but looking at the skirt,
it looks like the extruded plastic comes out in blobs
.  If it is not due to leakage, then I would suggest to also check that the filament is not slipping through the gears of the extruder.  If you have access to a suitable thermometer, you could also check that the hot-end temperature is stable at the level it should.
Final thought: have you ever succeeded printing with that filament spool?  It is unlikely, but it may be for example a defective one, or a mis-labelled one (so your printing temperature may be wrong).


Question:
Just last night the heat bed stopped working. It was fine up to 75 % of the print, then when it was done the bed was not on anymore. The display said it was set to 50 °C, but it was at 18 °C. I did try moving the pins, and that is not loose (very simple thing to try).

I want to know what could have happened and what to look for when I try to fix the heat bed.

Please note: I do have a multi-meter. I do not use a MOSFET (I do have plans to install on)

Upon further investigation, I tested the mother board for any voltage were the bed hooks up and there is nothing. I had the printer trying to heat the bed when I was testing. But the thermistor is working, when I unhooked the connection the thermistor went to 0 °C, when plugged in it went to 18 °C.

Is it the motherboard? How can I fix this knowing no power is being supplied to the bed from the motherboard? Do I need a new motherboard?

Answer:
This is a shot in the dark, but the vast majority of problems with a heating bed stopping to work is usually at the cables/connectors interface.
This is because in printers like the A6, the cable/connector is subject to constant mechanical stress, and - since
metal fatigue
is a thing - either the solder or the cable core cracks.
You should make good use of your tester to verify the integrity of the circuit in the bed and if it is not toasted you should be able to just repair the connection.
For many printers there exist "strain relief mods" to prevent this type of failure to happen.  The first one showing up for the A6 is
a full chain
, but normally is enough the have a small enclosure for the connector like
this one
for the CR-10.


Question:
Right now my heated bed is down and I had no time to try and fix it and I am trying to print something for a friend. I am having the PLA lift around the edges which I have NEVER experienced. The glue is not helping like it did with the heat. And I also tried rubbing alcohol on the masking tape I use, heard that helps and it was not that much better than the glue stick. What can I do to keep the plastic sticking to the bed during print.

I will note that the lift is not super bad, but I do like the littlest of lift on any print.

Answer:
Most of the same reccomendations that apply for adhesion to a hot bed apply for a cold one.  The first ones to come to mind:
really dial in the nozzle height
make the first layer taller than the rest (e.g.: 0.2mm if the rest of your print is 0.1mm)
print the first layer very slowly
print the first layer at higher temperature
use a brim or a raft (on my first printer, that had no heated bed, rafts gave the least deformation)
turn off the part fan for the first layer
adapt your model to reduce twisting forces (relief cuts, print it in parts, choose orientation wisely, etc...)
If your slicer has this feature, you could also try to print with a shroud.


Question:
As part of a project with my university, I have developed a new extruder to attach to a Prusa i3 MK2. My problem is that both the nozzle and PINDA probe have moved 17mm forward and 0.5mm to the right. As a result when I try and calibrate the printer it moves to the home position and the PINDA probe is too far out over the heatbed so it doesn't detect the printing surface. What is the simplest method of moving the home position so that the printer can be properly calibrated?

UPDATE:
I am planning on removing the heatbed and placing spacers that will move the printing surface 17mm forward. This should then prevent the printer losing any printing area and hopefully prevents me having to edit any code. Can anyone see any problems with this I'm overlooking?

The simplest thing to do would be to move extruder 17mm closer to be the same as the original printer but my deadline is fast approaching and I haven't time for a redesign that large.

Answer:
Consider the original installation with the orientation of the Pinda probe to the nozzle. Let's say for argument's sake that the Pinda probe is 3 mm to the right and directly in line with the nozzle on the y axis.
If you examine your new nozzle, I would expect that the relationship of the nozzle to the Pinda probe no longer matches the original spacing.
If possible, re-design the mount to place the Pinda probe in such a way as to match the original design.
Thanks for pointing out my oversight, Mac. If the relative position of the nozzle and pinda probe are as the original, the solution is then in changing the appropriate parameters in the firmware.
I found a
reference
for someone who had a bit smaller error in home position, but the concept is the same.
The link above points to information reading thus:
In Configuration_Prusa.h:
Code: Select all // Home position
define MANUAL_X_HOME_POS 0
define MANUAL_Y_HOME_POS -2.2
define MANUAL_Z_HOME_POS 0.15
// Travel limits after homing
define X_MAX_POS 250
define X_MIN_POS 0
define Y_MAX_POS 210
define Y_MIN_POS -2.2
define Z_MAX_POS 210
define Z_MIN_POS 0.15
it will be necessary to connect the printer via USB to a computer running an Arduino IDE and to load the Prusa specific files for that printer. Edit the noted location, save/write the configuration and test.
I would suggest small adjustments in only one or two parameters at a time, to avoid ambiguity in the cause/result sequence.


Question:
Is the firts time that I saw this movement after the printing has finishig and causes the nozzle crashes to the printed part and I noticed due the part is 14x8 and the nozzle is to near and below to the border of the shape. I supposed that some scripts has changed but, seems to be everything ok.

this is the end script:

G92 E0
G1 E-1.5000 F1800
; layer end
M104 S0 ; turn off extruder
M140 S0 ; turn off bed
G28 X0  ; home X axis
M84 ; disable motors
; Build Summary
;   Build time: 3 hours 9 minutes
;   Filament length: 12689.1 mm (12.69 m)
;   Plastic volume: 30520.78 mm^3 (30.52 cc)
;   Plastic weight: 38.15 g (0.08 lb)

Z axis moves down 4mm after finishing going to X0, why? I don't want the nozzle crashes the part on going to zero.

Answer:
You can use:
```
```
G91
G1 Z10
```
```
```
G91
```
make the printer use ralative positioning, while
```
G1 Z10
```
would move the gantry up of 10mm, reagrdless of its actual position.
In order to understand what's going on, you could experiment with the position of those lines in the script.
The safest bet it to insert them at the very top, but you could insert them straight after the homing of the X axis to understand if the drop you are seeing is caused by the homing command itself or by the ´M84´ one.
My
guess
is that the drop is actually caused by the latter.
```
M84
```
doesn't really "disable motors", rather it stops using energy to keep them still (i.e.: it stops the
idle hold
).  What I believe is happening in your case is that when you stop the idle hold, the weight and mechanical play of the X gantry causes it to move slightly (a bit like when you relax your body on the sofa and you "sink" in it a bit more).


Question:
Is there an integrated kickback protection in stepper motor drivers or should I make my own?
I am afraid the steppers might fry the driver or the arduino when i turn off the power for them.
I do that by turning off the power supply.
I haven't had an issue yet but it still bothers me.

Answer:
Kinda, sort of, but not really. I'll look at the A4988 (
datasheet
).
The motor pins are connected by diodes to ground and Vbb (the motor suppply voltage). Essentially, they act as a bridge rectifier making any back EMF or inductive spikes appear (rectified) on Vbb. If you were to suddenly power down the driver this could cause a rather large spike on Vbb.
According to the datasheet, there is a 40 V Zener on Vbb which will clamp the voltage to that level. (Another popular stepper driver, the DRV8825, does not appear to have this Zener - always check your datasheet!)
So, yes, there is inductive kickback protection. However, it only clamps the voltage to 40 V. Depending on the rest of your circuit, this could be quite damaging.
The datasheet recommends that a 100 μF capacitor be placed on Vbb. If you are driving a typical stepper motor with 2 A and 4 mH coil inductance, the energy stored in the coil is 8 mJ. This energy is only enough to take the capacitor up from 12 V to ~17.5 V, so if you have a large enough capacitor on your stepper driver (as you should!) then you're protected against inductive kickback.
Note that if you move the motors by hand then you can still build up a higher voltage on Vbb. I've heard anecdotes of people who damaged their printers like that.


Question:
I just got my first 3D printer today, QIDI X-ONE[2], and so far so good with the setup and getting my 1st print. I wanted to power off the printer, but I don't see any instructions on how to properly power off the machine.

Does anyone know how long I should wait, or what the minimum temperature would be safe to power down the machine?

Answer:
Kinda, sort of, but not really. I'll look at the A4988 (
datasheet
).
The motor pins are connected by diodes to ground and Vbb (the motor suppply voltage). Essentially, they act as a bridge rectifier making any back EMF or inductive spikes appear (rectified) on Vbb. If you were to suddenly power down the driver this could cause a rather large spike on Vbb.
According to the datasheet, there is a 40 V Zener on Vbb which will clamp the voltage to that level. (Another popular stepper driver, the DRV8825, does not appear to have this Zener - always check your datasheet!)
So, yes, there is inductive kickback protection. However, it only clamps the voltage to 40 V. Depending on the rest of your circuit, this could be quite damaging.
The datasheet recommends that a 100 μF capacitor be placed on Vbb. If you are driving a typical stepper motor with 2 A and 4 mH coil inductance, the energy stored in the coil is 8 mJ. This energy is only enough to take the capacitor up from 12 V to ~17.5 V, so if you have a large enough capacitor on your stepper driver (as you should!) then you're protected against inductive kickback.
Note that if you move the motors by hand then you can still build up a higher voltage on Vbb. I've heard anecdotes of people who damaged their printers like that.


Question:
Does anyone know of a good way to convert a 3D print file, like STL, to STEP - a useable file format for plastic injection molding companies?

I have tried to convert the files through a couple of programs without success. The most requested file is a STP or STEP file.  If there’s no easy way to convert it, which I don’t think there is, does anyone know someone good at re-creating CAD files?

Answer:
I've been able to manipulate an STL file using the hobbyist version (free) of Fusion 360. There's a series of steps involved that may require some research and experimentation, at least it did in my case.
One loads the STL file into Fusion 360 by using Insert, Mesh.
Once loaded, turn off history.
The next step is to
convert the mesh file to BREP
.
In that form, the surfaces can be edited and the model can be modified if necessary.
I have not exported to STEP, but have confirmed that
Fusion 360 supports STEP
as a valid export file format.
Both links provide additional information that may be of value to your project.
Consider also to double check your STL file to ensure it is manifold.
Meshmixer
is useful for such purposes. One model imported into Fusion 360 had entire faces removed due to a manifold error in the original model.


Question:
I am having problems with my tevo tarantula large bed 12Volt power supply, I am getting the thermal protection message when heating my bed with target temperature set to 115 degrees.
The process slows down after reaching 90.
I changed merlin settings to trigger thermal shutdown after 5minutes/2degrees and added a cover to the printer, so getting now 103 degrees (usually shutdown was at 100/101).

link to a video showing panel: https://photos.app.goo.gl/jiW9NE7wEB4H0mOy1

Answer:
You need to increase the power of the heated bed. With a given amount of power, there is an upper limit to the maximum temperature you can reach because at a given point losses due to conduction, convection and radiation will balance out the heating power and the temperature will not increase any more.
Sometimes, inability of the bed to heat up is due to the supply voltage sagging under load. First, measure the supply voltage with and without the bed turned on. If you find the supply drops significantly when the bed is turned on, you need a new power supply.
Otherwise, you will need to either:
Get a new, higher-power heated bed. Make sure that it is compatible with your electronics, or upgrade them as needed.
Increase the supply voltage so that the bed you already have will give more power. Some power supplies have a small adjustment potentiometer that lets you adjust the output voltage. Be careful when doing this. Even a small change in voltage gives a big increase in power. For a heated bed with resistance R at voltage U, the power dissipation is U
2
/R. Going from 12V to 13.5V already gives 26% more power.


Question:
I have modified my Prusa i3 MK2 printer so that the existing extruder motor has now been attached to a 5mm lead screw with a 1mm pitch. What is the easiest way to control the extruding of the printer now.

For example is it possible to change the settings in slic3er at all for the extruder? or would I have to download and edit the marlin firmware?

Answer:
The firmware of the printer reads the g-code, in this instance, for z-axis movement. The g-code provides only (primarily) millimeters of movement and direction, along with speed.
The firmware reads those figures, figuratively speaking, and knows from the values stored in the firmware, how many steps to rotate the motor, in what direction and at what rate.
I suppose if you were a glutton for punishment, you could write some code to convert the existing measurements to ones that are adjusted for the new screw, but that's just crazy. Imagine that your new screw provides for 3.729 times the movement that the old screw did per unit of rotation. You'd have to find all the z-movements in the code and apply that factor to those numbers. I suspect rounding errors might make for a less-than-satisfactory print.
As you've mentioned in your question about editing the firmware, one may expect that you have an idea what is involved. If not, that may be the topic of another post.


Question:
Anybody ever tried to retrofit a heatbed to the da Vinci mini w with the proper dimensions (165 mm x 165 mm or 6.5" x 6.5").

Where can I find a heatbed that fits and a corresponding power supply / PID controller?

Answer:
The firmware of the printer reads the g-code, in this instance, for z-axis movement. The g-code provides only (primarily) millimeters of movement and direction, along with speed.
The firmware reads those figures, figuratively speaking, and knows from the values stored in the firmware, how many steps to rotate the motor, in what direction and at what rate.
I suppose if you were a glutton for punishment, you could write some code to convert the existing measurements to ones that are adjusted for the new screw, but that's just crazy. Imagine that your new screw provides for 3.729 times the movement that the old screw did per unit of rotation. You'd have to find all the z-movements in the code and apply that factor to those numbers. I suspect rounding errors might make for a less-than-satisfactory print.
As you've mentioned in your question about editing the firmware, one may expect that you have an idea what is involved. If not, that may be the topic of another post.


Question:
This print failed a couple of hours in. I was wondering if the nature of the print surface, with lots of retracts (similarly the previous print which was OK) might have contributed to the clog, or if it's just bad luck? To be clear, the surface has lots of short dead-end, not just a wiggly perimeter.

The filament seemed to have stopped moving, and was cut through by the drive gear.

This was a genuine Titan Aero extruder, 0.4mm nozzle, 215C (on an Anet a8 printer)

Answer:
Reading your question it's not clear to me if you are referring to
filament retraction
(which is a configurable setting) or
surface recesses
which seems what you are referring to when writing:
the nature of the print surface, with lots of retracts
If it is the latter, then the answer is "no".  The amount of complexity of the surface of the model does not correlate
directly
to the possibility of the printer head clogging.
If it is the former, then the answer is "possibly".
It is in fact not so much the amount of retracts that affects the likelihood of a clog but rather their speed and lenght
.  If you retract
too quickly
and
too much
filament, you risk to have molten plastic being "sucked" into the cold end, solidify, and act as a glue, blocking the filament in place.
This is especially true for all-metal print heads
like titan aero, as plastic sticks a lot better to metal than to PTFE.
However,
with a
properly calibrated
retraction, you shouldn't experience problems
regardless of how many times / how often you retract the filament.
In general, it is a common misconception that retraction should work as a plunger, actively sucking in plastic that would otherwise ooze out of the nozzle.  However
all you need is to just release the pressure within the melting chamber, and in a direct drive (i.e.: non-bowden) extruder, this requires a very minimal retraction
.
Finally: what material are you printing in?  The picture shows a lot of oozing for being PLA. If you are using a flexible material like nylon or ninjaflex, you should probably just let retraction alone: the hysteresis in such materials is very high, and retraction often does not work predictably.  If it is PLA, I would try to increase the movement and retraction speed, and probably lower the temperature 10 or 15 degrees.  As for the retraction lenght, I don't own a titan, but I would expect the correct amount to be somewhere between 0.5mm and 2mm.


Question: After doing a lot of research, I've decided I want to purchase a Creality CR-10S as my first 3D printer. I'm trying to locate a reputable, local seller. Other than Amazon, which seems to have a bit of a mark-up on price, I'm finding several websites that seem to be located outside of the US. Can anyone direct me to a seller located in the US?

Answer:
I am afraid unless you are available to accept the mark-up, you won't find a
reputable seller
other than in mainland China.  The entire business model of Creality is "cheap-cheap-cheap B2C" and any step you add to the supply chain (like a reseller) will be:
An added cost
that will be reflected on the final price you pay
A reseller-based initiative
, meaning that it won't be part of a "creality global distribution network", but the project of that local entreprenour.
That said, I read in a couple of places that
tiny machines
(Houston, Texas)
does a good job by testing each unit prior to shipping, and has similar lead times than good sellers from China (a couple of weeks).
Please note I am not affiliated with them in any way.  For that matters, I don't even leave in North America nor have purchased anything from them.


Question:
I'm getting seemingly random lines scattered across the top surface of my prints:

Printer: Anycubic i3 mega

Slicer: Cura 3.2.1

Printer chosen in Cura: Prusa i3, Gcode flavor changed to RepRap

Cura Profile: Fine, "Outer before inner walls" enabled

What might be the reason?

Answer:
Our local library has a genuine Prusa i3 Mk2.5 that recently had this problem. Because of the number of fingers engaging such a system, it was not immediately discovered that a different profile had been selected in which the Z-hop was turned off.
Z-hop is a feature in which the nozzle lifts slightly (and is height-adjustable) as it moves from one portion of the print to another.
According to my brief research, Cura supports z-hop in the settings. Either it has to be activated or perhaps slightly increased. The aforementioned Prusa works great with 0.5 mm lift.


Question: One of the CAD programs I use is called TinkerCAD, which lets you export your design in either STL or OBJ form. What is the difference between these two file types? And which one is better to use?

Answer:
STL is the
de facto
standard in consumer-grade 3D printing
.  It is a bare-bone format that describes the shape of the object by defining the coordinates of all the vertices of all triangles that a surface may be subdivided into.
This means that in STL any curved surface is represented with an approximation of many very small faces.
OBJ is also somewhat common, but it was originally developed for computer graphics, not manufacturing, and as such is capaple to store information like the texture images to be applied to the surface, which are of no use in the 3D printing world.
In terms of geometry description, OBJ is more capable than STL, as it can describe "real" curves, without the need to approximate them to a series of polygons.  The benefit of this feature is however more theoretic than practical, as:
most entry-level CAD software don't make use of that feature and create a STL-equivalent OBJ file (so, still with polygons)
a typical STL model for 3D printing will have enough resolution to give the illusion of perfect curves (the same way a high-res screen gives the illusion of perfect curves, despite its pixels being arranged in a squared matrix),
the slicer/printer's firmware may themselves approximate an accurate curve to a series of segments
Short said,
I would suggest you use STL unless you have a specific reason not to
.
If you would find yourself in need to accurately describe curves I would rather use the STEP file format, as that has been specifically created for manufacturing, rather than "borrowed" from computer graphics.


Question:
About two days ago, I started seeing that my hotend was heating up erratically. I first noticed this while printing a part in PETG and the temp jumped to 260 °C. I shut down the printer at that time and first started checking the hardware. I noticed that the E3D V6 thermistor had been tightened too much. I disassembled the entire hotend, cleaned everything and then reassembled everything. I thought to retune the hotend and when I tried tuning it at 240 °C.

This is where the strange behavior occurs. The hotend steadily climbed up till about 200 °C. After that it just went nuts. I started seeing unreal temps such as 646 °C and such. At this point I thought the MEGA might be at fault. I replaced it and the hotend (an E3D V6 clone). This had the screw on glass thermistor. Again the same erratic behavior and unreal temp readings.

What could be wrong here? What am I missing? Can this be the heater cartridge?

Answer:
This can come from several sources:
Hardware
The thermistor or its connections might be damaged, and the fault is only observable when the hotend is hot or moved to a certain area. Start by checking the wiring! You may be able to repair a bad connection easily, but depending what was broken, you may need to replace something. In some cases squishing a thermistor cartridge too much can destroy the internals, so a replacement is needed.
A mainboard failure is more likely to just show a static temperature, and a heater failure would show as maybe not getting past a certain point.
Firmware
If it had not worked before or you changed the firmware, the firmware should also be a suspect. The firmware can 'fail' when using the wrong thermistor type/table which can result in a very big offset or bad slope, resulting in wrong or unaccurate readings.


Question:
I'm about to build a Prusa i3 dolly. I am confused whether to use RAMPS 1.4 or 1.5 or 1.6.

What is the big difference? Is it only the MOSFETs and the poly-fuses? If that is the case, would it be advisable to upgrade a RAMPS 1.4 board (replacing the MOSFETs, connectors, and fuses)?

Answer:
This can come from several sources:
Hardware
The thermistor or its connections might be damaged, and the fault is only observable when the hotend is hot or moved to a certain area. Start by checking the wiring! You may be able to repair a bad connection easily, but depending what was broken, you may need to replace something. In some cases squishing a thermistor cartridge too much can destroy the internals, so a replacement is needed.
A mainboard failure is more likely to just show a static temperature, and a heater failure would show as maybe not getting past a certain point.
Firmware
If it had not worked before or you changed the firmware, the firmware should also be a suspect. The firmware can 'fail' when using the wrong thermistor type/table which can result in a very big offset or bad slope, resulting in wrong or unaccurate readings.


Question: So like I sayed in the title, Why can't the Anet A6 do .05 layer height? I found that some printers can do .05 layer heights, but the Anet A6 can't? I am interested to know if it is the stepper motors or the threaded rods or something. Maybe this is something I can do a small "test print" on?

Answer:
I'm not familiar with the Anet A6 specifically, but as many other things in a 3D printer, the minimum layer height is co-determined by a number of factors.  For the Z-axis the factors I am aware of are:
The number of steps in the stepper motor
The geometry of the lead screw
The tolerance with which the lead screw has been machined
The microstep settings
The quality of the stepper drivers
The amount of play and flexibility of the X-axis gantry
The ration between filament and nozzle diameter
The precision of the extruder's stepper motor
...
Many printers that claim to have ridiculously low minimum Z-layer height do so by relying on the mathematical model only.  It goes something like this: the lead screw has an offset of 1mm per revolution, the stepper motor makes 200 steps and is set for 32 microsteps per step so the minimum resolution should be...
```
```
1mm / (200 * 32) = 0.0002mm
```
```
The reality is however different.  For example: the lead screw may have been machined with a tolerance of 0.002mm, so to make sure a layer has a thickness >0mm its heigh should be >0.004mm (20 times the theoretical limit computed with the microsteps).  But to make sure layers have the same height ±10% you would need to increase the minimum layer heigh of an order of magnitude, bringing it to 0.04mm.  A similar reasoning applies for the amount of play in the gantry, while the ratio between filament and nozzle influences the minimum volume of plastic that can be extruded per step (for very thin layers you want to be able to extrude a minimal amount of it).
At the end of the day
this is a typical case of "a chain is only as strong as its weakest link"
: the minimum layer height of a printer is affected much more dramatically by the limitations of the most imprecise component in the printer than by the performance of its best one.
As for your question about breaking the printer by issuing g-code with very thin layers: should you issue gcode that requires layers below that limit, the firmware will simply print at the same z-height (see comments, credits to Tom).
I'm unaware of people having permanently damaged their machines by issuing code with too thin Z-layers.  But given how the firmware operates, I'd expect the quality of the print to be negatively affected, the filament to be possibly chewed by the cobbed wheel and in extreme cases cloggig of the printer head.


Question:
I re-read my question and realized I made a confusing one, so I am rewording a LOT.

So the software I use is Craftware. When it comes to the first layer I have it set to .25mm, with the following layers being whatever I specify otherwise. And because of this there shouldn't be a difference with the first layer even though I choose different layer heights based on the project. But for some reason it is not the case.

When printing .2mm layer height everything works great. The print adheres amazing, the nozzle is at a really good height. Everything simply works.

When printing .1mm the first layer does not stick. A lot less plastic is coming out the nozzle. And it is a disaster. Have tried increasing the amount of flow a bit, but didn't help (I might need to raise it a lot more)

So I don't understand what is going wrong. The first layer is supposed to be set at .25mm no matter what the layer height is otherwise. What do I need to do or look at?

Answer:
You have asked several questions here.
"why is first layer set to 0.25" -- check the gcode file, opening it in a text editor, to see what layer values are specified.
"looks like under-extrude" -- please show a picture.  If it's purely that the print failing to adhere, you may need to adjust the Z-zero point slightly. Or perhaps When you printed at 0.2mm, for whatever reason the transverse stress on the base layer is less than when printing at 0.1 mm (e.g., linear speed adjustments needed).
Is the second layer somehow not adhering to the first layer?  It is possible that the linear speed setting for the first layer is too high and that should be adjusted.  Or perhaps the z-height for the second layer is inconsistent with a 0.1mm layer setting, so check the gcode there too.
In general, adherence problems can be dealt with by adding a raft or brim. See if that suffices.


Question: Harking back to the days of "singing disk drives," I am wondering if anyone's written music to be performed on a 3D printer. Most of us have noticed in passing that the servo motors for X and Y drive generate a different pitch depending on motion speed. With some care and experimentation, one could write g-code to produce not only a tone but even a 2-tone chord.  So -- has this been done? Does anyone want to do so? (Note that there's no need to simultaneously produce a print, but that would be even classier).

Answer:
Yes, it has been done before, see
here
and
here.
The README file of the first repository linked above contains a detailed explanation of the basic idea/calculations involved.  A short excerpt:
As you can set the parameters of G1 in such a way as to precisely control the velocity and the distance of a movement along a certain axis, you can control the operation frequency of the stepper motors as well as the actual time to complete a movement.
On another note (pun intended), you can also play music by using the code
```
M300
```
.


Question:
I've built and done some simple tests on a TEVO Tarantula but I've noticed some pretty dramatic under extrusions.

My equipment:

TEVO Tarantula;

Jim Brown's easy config fork of Marlin;

Titan extruder (came with printer).

I've updated the firmware with the 400 steps as advised and calibrated the extrusion with the 100 mm method:

When I run the calibration with the Titan extruder, only the 400 steps is fine and works as expected;

When I connect the Bowden tube to the hotend and calibrate (at 200, 225 and 250°C), I see only ~50 mm of extrusion.

I've disassemble the hot end, changed filament and I can't see any signs of blockage. The Bowden tube in the hotend is not showing any signs of melting etc. and it is pushed all the way down to the hotend, as per the instructions.

So, what's going with this?

Answer:
It is considered good practice to limit your post to one question at a time. The question about hardware and material is too broad to be a good question and I will set that aside.
Equally unfortunate, your drawing is ambiguous. I suppose if English is not your native language, I'm not helping things either.
The drawing has some errors that make it challenging to be certain of a correct answer, but I can provide you with some useful information as a direct result of a test print created today.
The test print for my printer creates a series of spool shapes within retainer shapes. More complex than a simply cylinder making the test that much more difficult.
My printer is able to print without problem parts that are 1.0 mm apart, 0.8 mm apart and 0.6 mm apart. The test failed at the 0.4 mm spacing and the 0.3 mm spacing, telling me that I need to perform some tuning.
Your question asks about 0.05 mm spacing. I think you will not find an FDM  printer that will manage such separation without bonding together the individual components. FDM printers use filament.
You may also not find that an SLA or DLP printer can provide such tight tolerances. It is the most likely source of a success, however. I have only minimal exposure to tolerance in this type of printer. SLA/DLP printers use lasers/light and liquid resin. They can accomplish 0.05 mm layer thickness, even as small as 0.025 mm layers, but I do not know the figures for horizontal precision/accuracy/tolerance.
SLS printers use a nylon powder and a laser to fuse the powder together to form the model. My SLS printer uses 0.050 mm powder. To accomplish the separation you require would mean a single layer of powder will separate the individual segments of the model. This is not practical for this type of printer.
Your best bet would be to consult with a 3D printing service that uses SLA printers. SLA is likely to be more precise than DLP due to the method of exposing the resin, although that is not a universal truth.


Question:
Is there any commonly printed plastic which I can buy that might be transparent to UV light?

I wish to print a mould, then pour in my plastic which requires a UV light to activate the curing process.

Answer:
This is more of a Chemistry question, but seeing as we love 3D printing with exotics, here are a few.
Topas
olefin copolymer
From the mfr description page,
TOPAS cyclic olefin copolymer, or COC, is an incredibly pure polymer -
in fact, it's purer than most grades of medical glass. Unlike glass,
it has a non-ionic, inert surface to minimize reactivity,
denaturation, agglomeration, delamination and other traditional glass
concerns. And when it comes to maintaining purity, TOPAS medical grade
plastics can be sterilized via all common methods. Leachables and
extractables are extremely low. Reduce risk and increase performance
by maintaining the benign, protective environment that TOPAS COC-based
devices provide.
Medical grades of TOPAS COC are extremely clear, and are optically
suitable for replacing glass in many applications.
I'm not sure of its melting point, or of the speed of solidification (which affects extruder rate, motion etc).
Recommended at
this Chem.SE question
, PMMA and others
edit
Because answers there have links of their own, I"m not repeating the various technical leads available there.
Now you will have to investigate their melting points and flow rates, etc. to see if these can be coerced to function in an extrusion printer.


Question: Whenever it start printing the extruder starts clicking, I tried adjusting the voltage with no luck, it's still clicking. And it doesn't extrude a lot of plastic sometimes it even stops extruding but the extruder is still turning. Can someone help?

Answer:
The clicking you are hearing is either the stepper motor skipping steps or the hobbed gear losing grip on the filament.
Either way, it means that the filament opposes an unusually high resistence to be pushed forward.
A key information to be able to diagnose your problem is whether the clicking is on the firsts couple of layers or throughout the print.
If it is only for the first 1-3 layers the problem is likely to be the printing bed too high
(or deformed), so that the nozzle touches it and the bed acts a "lid" on the nozzle preventing the molten plastic to get out.  If this is the case, adjust the printing bed to be flat and level (and the nozzle at the right height when homed on the Z axis.
If the problem persists throughout the full print
the problem is likely to be related to one of the following:
the extruder not managing to get a firm grip
on the filament (worn teeth, slack spring, ...)
the stepper motor being underpowered
(this seems not to be your case, given that you have already adjusted the voltage)
a clog, adhesion, or restriction in either the bowden tube or the extruder
, for which the best solution is disassemble, inspect and clean (eventually changing the bowden tube if it has been deformed).


Question: It's my first time printing in vase mode, and I noticed my printer underextruding badly. The settings have not been changed from default vase mode settings in slicer, and earlier I was printing non-vase mode and the prints came out fine. Layer height is 0.2 mm and perimeter width is 0.3 mm.

Answer:
Finding the cause of under-extrusion is very hard as a lot of parameters of the print process can influence this. There are some nice websites that describe these problems in detail. From your question it is unclear what you have done to solve the problem, or if you have printed products after the vase mode and shown us a picture of that (this eliminates a lot of possible problems).
A nice overview is given by
Ultimaker
, but other sources may help you to find the root cause, e.g.
Simplify3D
. If the issue is related to the filament and hot-end,
Printrbot
,
Trideus
and
Rigid.ink
may help you solve the problem.
Important is to isolate your problem! Not knowing what printer you have, your printer has (or potentially has) the folowing modules/elements that may be causing the underextrusion:
the slicer (highly suspicious),
the material/filament and the spool holder (suspicious),
the extruder or feeder (suspicious),
the hot-end (suspicious),
the Bowden tube (suspicious if you have one).
Note that to find the root cause you should tackle this by elimination, this way you make sure that certain modules are not causing the problem. Also keep in mind that the vase mode prints a single outline/perimeter shell and won't make any retracts (so the Z axis will continuously rise), in which defects are shown instantly. Please, take a close look at your normal multi perimeter print.
How to fix under extrusion!
Under extrusion is probably one of the hardest to find the direct cause as there are so many variables to consider. Please find below some of the variables that can affect your printing quality marked in bold face.
Material and material settings
The material you use needs to be resembled correctly, so it is important and easiest thing to check first if your print is suffering from under-extrusion due to incorrect material settings. The material settings in your slicer (or the material profile on your printer for the more fancy printers) should match the material you are printing. So please check the
filament diameter
with a caliper and measure the diameter at various points; take the mean diameter of at least 3 to 5 measurements. Furthermore,
temperature
is also an important factor;
too low temperatures
will cause that the extruder has to push harder as the material is less viscous due to the fact it is not heated properly. Note that this can also happen if the flow of the filament is too high and the heater cannot keep up. It is these high pressures that cause the under extrusion as it may not flow fluidly. In contrast to too low temperatures,
too high temperatures
, can also cause problems. Very high temperatures can change the structure of the material, this is often referred to as carbonization causing
deposits
(clogs) in the nozzle. A word of advice,
Please check your filament spool/box (or sometimes a paper in the box or bag) for the proper temperatures
.
Next to the temperature, other important material settings are the
print speed
, the
layer height
and the
nozzle size
as these properties further define the rate at which the
filament volume
is deposited. For instance, a
too high of a volume flow
not only can lead to the previously mentioned cooling of the nozzle, but also is limited by the diameter of the nozzle, you just cannot push more through the nozzle is capable of as the friction will increase (the smallest opening in the system determines the maximum rate of volume flow). If you do, this will lead to under-extrusion. To
find the optimum between speed and temperature
, a good balance between these needs to be found. A typical way to do that is by the use of printing calibration temperature towers, preferably at various speeds. To print faster, you need a higher temperature, but printing at lower temperatures because of overhangs, you might need to decrease the speed to get a proper extrusion (and maybe also part cooling).
Don't just focus on the hot end part, also take a closer look at the filament spool itself, or better, how the spool unrolls. Is the
spool of filament unrolling correctly/freely
without a lot of friction (does it make
sharp bends
, or does it go
through a tube
having friction from its container to the extruder), or is the
filament not correctly wound causing tangled filament
(which create a lot of friction preventing enough material to be transported to the hot end) which could stress the extruder.
For some materials that are hydrophilic (they attract water and trap it in the filament, this happens e.g. with PLA, PVA, Nylon and maybe even more) printing the
filament with contained water, the water will turn into steam causing bubbles
in the deposited filament and interfere with the flow deposition. This effect sometimes makes a distinct sound like popping bubbles. Always store your filament in a sealed container or bag and use desiccants bags. Moisture can cause damage to the printer as the
filament swells when taking up moisture
; this could lead to various jams. Last but not least, filament with moisture in it has less mechanical properties after printing than dry filament (up to 33% less).
The extruder/feeder and Bowden tube
The extruder/feeder pushes or feeds material into the hot end, or into a tube (called Bowden tube). Under-extrusion caused by the extruder is typically characterized by the fact that filament is not properly fed to the hot end as a result of
too much friction in the tube or hot end
,
too less grip on the filament
or
filament grinding
(the extruder gear 'eating away' the filament).
Too much friction could even cause your stepper to tick or click
, basically turning back as the pressure on the filament exerts so much pressure that the stepper is rotated back;
increasing the feeder tension
on the filament (by
adjusting the screw on the extruder/feeder
would fix that). Grinding is easily spotted when removing the filament; it will clearly show that the gear has worn away circle shapes. Furthermore,
filament taken out of the printer should show visible marks on the material
as imprints of the extruder gear,
if completely smooth, the feeder tension is too less
. On the other hand,
too much tension on the feeder could flatten the filament, which leads the previously mentioned grinding effect
. If you encounter grinding, please assure that you
clean the extruder by removing the filament powder and chunks
the grinding produced and recheck the extruder/feeder tension before continuing printing again. Be sure that the
grinding particles have not entered the Bowden tube as it causes friction
. Cleaning them regularly or replacing them once a year is advisable depending on the usage (or once every x kilometers of filament). Furthermore,
larger diameter filament (2.85 or 3 mm) can cause additional friction (in the Bowden tube or the extruder/feeder) as towards the end of the spool
, the filament is wound tight along a small diameter spool center causing strongly bend filament that exerts pressure as it acts like a spring creating friction at the walls of the tubes.
The hot-end
The hot end can also be a culprit for under-extrusion.
Partial blockage of the nozzle as a result of carbonization
(buildup of carbon or carbonized material in the nozzle). Even
left over material from previous prints inside the nozzle
(
unflushed residue
) may change the volume of the nozzle when the material you printed before needed a higher temperature than the current you're printing. Also try to get
good quality filament
, it might be that the
quality is just not constant for the whole spool
. Too clean the inside of the nozzle, a few techniques exist to remove blockage. By
performing a "cold pull" or using the
```
atomic method
```
. Both techniques rely on the mechanism to insert the (cleaning) filament when it's hot and remove it quickly at a lower temperature. E.g. see
here
or
here
.


Question:
https://photos.app.goo.gl/O6yPf3sDeV1yhS0C2

I tried to illustrate my problem in the videos above, two of them show the weird movement and the other shows me clicking on the home button repeatedly.

Some Info:

Marlin 1.1.8 or 2.0.0 (same problem in both)

Robotdyn RAMPS 1.4

0.9 angle stepper motors

DRV8825 drivers configured at 0.8V Vref

Anet A2 Plus stock for all the rest

Answer:
As far as I can see on the attached videos your homing movement is reversed.
as per Marlin, the homing for X shall move towards the left side and for Y to the back of the printer.
That could occur when: cable connectors to stepper motors are reversed, or the motor is assembled the other way (you can set reverse direction in Marlin)
The other issue is steps/mm calibration need to be done see source below.
The high pitch in the video could also point that the drv8825 is shutting down the movement as it is overloaded.
please also check that for vref
Configuring Vref In order to measure Vref you first need to turn on
  your printer as you normally would. If you only connecct using USB,
  but not external power, you get a wrong reading.
You need to turn on your multimeter and set it at 2v. Put the red one
  on the potentiometer and the Black one on the Gnd pin. Both are marked
  on the images here.
Before starting this I read they come with a very high vref setting,
  and it is recommended to start around 0.5v Vref. After measuring mine,
  I can confirm they come with a very high initial setting. Mine both
  came at 1,65v or so! - Yours might be different, which just underlines
  the importance of doing this.
Contrary to normal potentiometer usage, the ones on most copies/clones
  of DRV8825 are lowered by turning clock-wise, so that is what we will
  do, to we hit 0,5v on each. - A quarter of a full turn lowered it to
  0,7v, - after that it goes very, very rapidly down, so aim for the
  quarter of a turn + a tiny tad more. If you buy your DRV8825 directly
  from pololu.com the Potentiometer are dialed up by turning it
  clock-wise:
source


Question:
I have an Anet A8 printer for about 4 months, set up pretty well (or so I thought) and printing a number of models pretty well. I made a large 3" x 6" box with a sliding lid yesterday and when it was done there was a gap on one side when the lid was slid on. I checked the parts and it turns out they are not square - which means the X and Y axes are not square to each other.

I'm wondering how to adjust this - I'm thinking that extending the distance between the back of the frame and the front by adjusting the threaded rods that separate them to a wider distance on the side where the angle is obtuse. Obviously one of the first things I'll check is that the distance between the front and back is the same (I can't imagine why I never checked that before, come to think of it).

Does this sound like a sound plan?

Answer:
It is hard to determine the exact source of the problem as there are few possibilities (I am assuming that you have a single nozzle and only one filament in use):
One of the hardest issues for me to get on my printer was fact that my auto-level sensor was mounted about 0.5mm too high - so please check that as this will give you a bit higher Z than expected.
Printing speed matters  - for some prints I was slowing my printer to 20% of nominal speed to get adhesion
a hair-spray layer or a masking tape on the bed could help with getting the grip
also you could play with nozzle temperature de/increasing by 5 degrees and see how it is going


Question:
I have a simple printer bot metal with a heated bed, the heated bed I am not using. I am using conductive pla by protopasta

The conductive pla is not that strong, so when I take my pieces off the board, sometimes they break. The only time it appears to be invincibly strong is when it sticks to the bed plate! I cannot get the skirt off the bed plate, no matter what I try

a razor blade does not work, even when the bed isn’t heated and after dumping a bunch of acetone on the board

using no skirt does not work, as the printer clogs itself

it is difficult enough to remove to the point that printing itself isn’t fun

when scratching it off, the pieces only chip, because they stick better to the bed than they do to themselves (unlike PLA)

What’s a good way to remove a conductive pla skirt from one of the beds? The skirt is the initial outline a printer lays down, it is very thin

Answer:
Based on your description "it is very thin" about the skirt, and by the other characteristics you've provided, I suggest that your z-height for the first layer is suspect of being too small, too close to the bed.
If you have calibration specific to z-height only, re-calibrate and make a test  print with skirt. If the test is better, this tells you that the previous setting was at fault. If the test is not better, use a different setting by 0.01 mm or 0.02 mm and run another test.


Question:
Ultimaker Cura offers a platform support type of “touching buildplate” which enables the printer to only make a raft for parts of the object that should be touching the build plate. It also offers “everywhere” for any object that might be hanging over the build plate.

I have a need to only offer support for overhangs up to a certain z height, such any overhang located at a z-point of 4 mm or below. Is there a software that will enable this, either as a setting/addition to Ultimaker Cura or just a G-code export for Pronterface?

Answer:
Is there a software that will enable this?
Yes, as of Ultimaker Cura 3.3 Beta, Ultimaker Cura allows you to specify an area which will not be considered for adding supports. In your case you could define everything above 4 mm to be excluded from building support structures.
You can look
here
for this very new feature, it might be what you're looking for.


Question:
For example, to make a DIY cartesian 3d printer you could use/do the following:

Create G-code using a program of your choice.

Load it into Universal G-code Sender (GRBL).

Pass it into an Arduino with GRBL.

The arduino can pass the instructions to the drivers through a GRBL arduino uno shield.

The drivers will control the steppers.

If you want to make a DYI delta 3d printer, which point of this whole process needs to be altered in order for the delta printer to work properly? Is there an existing open source software for delta printers/cncs?

EDIT: This question could be asked about any kind of non-cartesian 3d printer, including Delta, SCARA, Polar, etc.

Answer:
The short answer is that the handling of the non-cartesian design is done by the motion-control firmware running on the Arduino.
The long answer:
I don't believe GRBL supports non-cartesian designs, and it is not commonly used for printers. It is more often used for mills, routers, or laser machines. 3D printers will typically use a firmware such as Marlin, which supports several printer designs, including Delta machines.
At no point is the g-code itself changed. The motion control firmware running on the Arduino or other controller interprets the g-code and determines which way and when to step each motor to accomplish the motion.
With a simple cartesian machine, commands for the X-axis only relate to the X-axis motor, but for a non-cartesian machine the axis and motors have complex relationships. The firmware must be programmed and configured to control the motors correctly.
The g-code itself is never passed to the drivers. The commands to the driver are simple electrical signals to "enable" (to energize the motor power - even to just hold position), "direction" (which way to rotate the motor shaft), and "step" (which causes the motor to rotate by one step in the selected direction).


Question:
I found an old Creaform3D EXAscan laying around at the company I work for, and tried to plug it on a computer to see if it still works.

I discovered that it uses a software called RapidForm for data acquisition, but its license is expired.

I looked in the manufacturer site for drivers or something similar but there isn't anything.

Is there any other software or way to read the data coming from such scanner?

Answer:
So if the original manufacturer still exists,
(which they appear to, and even list your scanner under 'legacy' products)
your best chance of getting it working is going to be to contact them directly. Using proprietary hardware WITHOUT the associated proprietary software can range from merely tedious but possible, to outright impossible, depending on the specific company. Oftentimes with tech products like this, the business model isn't about the product itself, but about the license fees for the software to use it. That they can charge yearly for. It's possible that the raw data is just a stereo camera file with extensions renamed, and equally possible that the firmware in the scanner will do some sort of check for valid license before it will even start scanning, they don't really have much info on their legacy products on their page


Question: How do I know what nozzle to get for my Anet A6 printer? I want to get some hardened nozzles because I would love to print with some glow in the dark filament, but I know that eats up brass nozzles fast. But there is so many thread differences so I don't know which one to get, or even what thread the Anet A6 is. Could I have some help finding the thread type and what hardened nozzles would be recommended?

Answer:
So if the original manufacturer still exists,
(which they appear to, and even list your scanner under 'legacy' products)
your best chance of getting it working is going to be to contact them directly. Using proprietary hardware WITHOUT the associated proprietary software can range from merely tedious but possible, to outright impossible, depending on the specific company. Oftentimes with tech products like this, the business model isn't about the product itself, but about the license fees for the software to use it. That they can charge yearly for. It's possible that the raw data is just a stereo camera file with extensions renamed, and equally possible that the firmware in the scanner will do some sort of check for valid license before it will even start scanning, they don't really have much info on their legacy products on their page


Question:
I hear that heated beds can help with removing finished prints, but not all printers have them!

Is this a nice to have or must have feature?

Are there any downsides to heated beds?

Answer: It can help with bed adhesion. However, most 3D printing plastics will warp without a heated bed (since they shrink as they cool). ABS is notorious for this, although PLA is not so bad, and you can get away without a heated bed for small parts. ABS is so sensitive that you may need a heated (or at least draught-proof) enclosure, as well as a heated bed. If you are considering buying a 3D printer, it is best to get one with a heated bed, unless you are on a very restricted budget. If you buy a printer without a heated bed, you will soon realise that you need one.


Question:
I'm building a 40x40x40cm corexy and I am quite impatient so I want the heated to reach the target temperature as fast as possible, so I ordered a Keenovo silicone heater
It is a 220VAC 1200Watt bed, so I really want to make sure that it is safe to use.
I also bought a Crydom D2450 SSR.

Could someone tell me if the wiring in the diagram I made below is safe?

Do I need to put a fuse or some other kind of safety?

Answer:
The answer is, yes you can, but you need to follow guidelines.
Reversing +/- or otherwise incorrectly connecting power can destroy your electronics and cause fire hazard.
From
RepRap wiki - RAMPS 1.4
Maximum Input Voltage Power Supply without diode There are three
limiting factors to the maximum voltage that you can put into the
RAMPS:
The Arduino Mega maximum input voltage Filtering capacitor maximum
voltages PTC fuse maximum voltages First, the 1N4004 diode connects
the RAMPS input voltage to the Arduino Mega which has a recommended
maximum input voltage of 12 volts. If your board does not have this
diode soldered in (or if you cut it), you will need to power the Mega
through the USB connector or through a separate 5v line, but this
allows a higher RAMPS voltage.
Second, most boards use 25v or 35v aluminum electrolytic capactors
(C2, C3, C4, C6, C7, C9, and C10). To be safe, you should only go to
half of your rated maximum voltage -- thus if your board has 35v
capacitors (code VZA) then you should use a maximum input of 17.5v.
The absolute maximum voltage is determined by the pololu servo
drivers, which themselves are limited to 35V.
Third, the MF-R500 (5A) PTC fuse is rated to 30V and the MF-R1100
(11A) PTC fuse is rated to 16V. They will need to be replaced with
real fuses.
Power Supply with diode If your board has a 1N4004 diode soldered in,
do not apply more than 12 V to it. Original flavor Arduino Mega are
rated to 12 V input. While Arduino Mega 2560 can take 20 V, it is not
recommended.


Question: With hot plastic being laid down layer after layer, I am worried about fumes. Should I only print in a well ventilated work space? Should I add additional ventilation?

Answer:
There are some contradicting sources out there on whether plastics, especially ABS, have toxic fumes. It is well known that PLA is food safe, as it is an organic, biodegradable polymer being based on a particular cornstarch. This means that PLA
is
safe when printing, although it can produce foul smells from the dyes and other ingredients. As for the other plastics, it is most commonly said that the fumes are toxic, although, as stated earlier, there are some contradicting topics on this.
Here
and
here
are some articles for further reading.


Question:
Recently I noticed that Cura always is giving me less printing time than the print itself takes on my TEVO Tarantula with Marlin firmware.

The time difference is about 15 %, at requested 50 mm/s printing speed.

How could I verify real printing speed?

Answer:
Printing speed is dependent by the firmware and physical properties of your printer
.
Slicers typically compute the expected time by assuming the printer will execute
exactly
what it is instructed to do, but a printer is a real object, with mass and momentum, and stepper motors that have an upper limit for their power output and rotation speed.
So for example, the GCODE may say "extrude 200mm at 100mm/s" and the slicer will compute that operation as taking 2 seconds.  However the printer will need to accelerate and decelerate at the extremes of the movement, and it may even be incapable of reaching speeds over 70mm/s, so the
actual
operation will likely take 3 seconds or more.
Accelerations and decelerations account for most of the difference between ideal time and real one, and since the number and intensity of those is totally dependent by the GCODE/model being printed,
it is not possible to simply multiply the computed time for a given factor
(for example
```
1.15
```
, as your question seems to imply).  A large cylinder printed in vase mode will have a printing time much more similar to the computed one that an intricate model with a very complex surface, for example.
In recent years, slicers that are maintained by a printer manufacturer (cura, slic3r PE) have become better at estimating printing times for their own printers, as the settings of the firmware are accounted for in the actual estimating algorithm.
If you use Octoprint, you may have noticed that the time estimate octoprint gives improves over time, as
octoprint will analyse the GCODE and measure the elapsed time, and will be able to guesstimate the real time with an increasingly degree of accuracy
.


Question:
I'm currently designing a RepRap 3D printer that will not have a heated bed. I have heard that it is possible to use a power brick with commercial printers lacking heatbeds. Is this possible with a RepRap printer using a RAMPS board?

I'm referring specifically to the TronXY X1 power brick. I was wondering if it we're possible to use the same TronXY X1 power brick with a standard RAMPS 1.4 board - rather than the special board the TronXY X1 uses.

Answer:
Printing speed is dependent by the firmware and physical properties of your printer
.
Slicers typically compute the expected time by assuming the printer will execute
exactly
what it is instructed to do, but a printer is a real object, with mass and momentum, and stepper motors that have an upper limit for their power output and rotation speed.
So for example, the GCODE may say "extrude 200mm at 100mm/s" and the slicer will compute that operation as taking 2 seconds.  However the printer will need to accelerate and decelerate at the extremes of the movement, and it may even be incapable of reaching speeds over 70mm/s, so the
actual
operation will likely take 3 seconds or more.
Accelerations and decelerations account for most of the difference between ideal time and real one, and since the number and intensity of those is totally dependent by the GCODE/model being printed,
it is not possible to simply multiply the computed time for a given factor
(for example
```
1.15
```
, as your question seems to imply).  A large cylinder printed in vase mode will have a printing time much more similar to the computed one that an intricate model with a very complex surface, for example.
In recent years, slicers that are maintained by a printer manufacturer (cura, slic3r PE) have become better at estimating printing times for their own printers, as the settings of the firmware are accounted for in the actual estimating algorithm.
If you use Octoprint, you may have noticed that the time estimate octoprint gives improves over time, as
octoprint will analyse the GCODE and measure the elapsed time, and will be able to guesstimate the real time with an increasingly degree of accuracy
.


Question:
Note: I have extended my question as some of you mentioned that the question is not clear.

I am using a RAMPS 1.4 board with an Arduino mega 2560. I need to drive a stepper motor as an extruder using either E0 or E1. I am using Repetier-Firmware and can drive the extruder (stepper motor) using the E0 (RAMPS 1.4).
Now for my application, I need to make sure that the extruder is in home position before it starts to drive for the very first time. I am trying to use a  switch to connect to the end stop and perform this homing operation. I can do this for X, Y, and Z axes. I was wondering how (h/w connections and firmware modification) can I do it for the extruder?

Answer:
The edited question
appears to mention that
the actual extruders of the print head need to home / limit themselves
. The answer is that this is not required. When operating direct or Bowden driven extruder setups, you know (or you can measure or find out experimentally) the distance that the filament has to travel from extruder entry to hot end (e.g. to load new filament). If already loaded, because you have printed before, you also know where the filament is (filament could stop after printing, personally I retract the filament en few mm after a print). When a new print starts you usually reverse the retraction at temperature and extrude some extra filament to prime the nozzle to counteract oozed out filament for instance. At that point, the nozzle is primed and the gcode G92 E0 is then used to tell the extruder this is the start at zero length, sort of the home position of the filament. All this is usually done in the start code of your slicer, similar to  disabling bed and hot end temperature or final retract is done in the end code of your slicer.
This answer below addresses the initial question
, this question was not quite clear. It was
phrased as of the head containing the extruders needed to be homed correctly
. The normal end-stops (can be mechanical or optical switches) already ensure that the printer head (containing the extruder or extruders) is homed correctly (if correctly configured in your printer firmware). The home offsets you define in the firmware define that you start at the origin (0,0,0).
Your question does not state what firmware you use, but e.g. in Marlin firmware these settings are found in the
firmware configuration file
.
In this file the following is defined:
```
```
// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS 0
#define Y_MIN_POS 0
```
```
These values must be changed according to the offset between your switch and the origin of the heat bed (e.g. Prusa style printers have the origin at the front left).
For my Prusa clone printer I have defined:
```
```
// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS -35
#define Y_MIN_POS -12
```
```
What this says is that the homing switch for the X axis is 35 mm left of the origin, etc.


Question:
Are these vertical lines described as "banding"?

Would the most likely culprit be the extruder?

FWIW, this was printed in "vase mode".

Answer:
Banding usually refers to Z banding and manifests itself in a wavy/non-straight wall in Z direction:
This sort of banding is related to mechanical or design issues of the printer (lead screw (nuts), belts, play, etc.)
Your print, however, shows local thicker walls. It appears that these local thicker parts are related to the change in direction of the print head. A 3D printer does not print curved lines or arcs (although
G-codes do exist for arc movement
), all movements are straight lines. So the cylinder consists of straight lines. By rendering the cylinder with more triangels you could increase the amount of straight lines to form a better approximation of the cylinder circumference. You could also try to lower the printing speed, but since you did not post any printing parameters that will be a guess.


Question:
I have a 15x15 cm heating resistor from my current printer (printing area: 12x12 cm).

I would like to switch to a glass bed and to rework my printer to increase the printing area to 20 cm (22x22 cm glass plate).

Would it be possible to use the old heating resistor placed only in the centre? this way I would have a smaller heated bed for ABS and a bigger one for PLA.

Would the glass crack due to non uniform heating? This is because glass has a conductivity of less than 5 W/mK, therefore the hot area will stay hot and basically never really spread the heat to the surrounding area. So the frame will be cold and the center hot, causing stresses.

Related: https://engineering.stackexchange.com/questions/31842/how-much-an-unevenly-heated-glass-plate-bows

Answer:
The glass will be taking up the heat to slowly cover its full area.
That means two things:
it will not crack as there is no thermal shock
it will put more pressure on the heater as there will be bigger heat absorption, so in an edge case, you could end-up with not getting a required temperature on the glass surface and/or the heating process will be very slow.
In that case, I personally will try that out and then if I have an issue with getting proper temperature, then I will buy a new heater.
A comment regarding heat expansion:
my glass is about 20mm longer than the bed and it is warm during the printing process. The 'breaking' stress is connected with temperature shock (an immediate temp change), not a relatively slow heating process. However, borosilicate glass also known as Pyrex (TM) expands very little. Much less than most metals. This is why it doesn't break when exposed to sudden hot and cold changes. So in short words - check tea lighter under your tea-pot and see how te heat is comming out from the centre
source


Question:
How does Z offset (M851) work with an auto leveling sensor? Does it add the Z offset to the offset of the G29 mesh? or the G29 value replaces the M851?

My printer is an Anet A8 with Marlin firmware, I was having issues with the autoleveling sensor and reset the Z offset to 0 and let G29 get the mesh offsets and its working good now.

I was looking through Marlin G-code page but couldn't figure out how G29 affects M851 or vice-versa.

My setup with level issues:

M851 Z0
G28
M211 S0 ;turned endstops off and got a paper to find the zoffset
M851 Z-0.59
M500
M211 S1

And G29 before printing.

Answer:
```
G28
```
instructs the printer to home itself to the X an Y endstops and the Z sensor determines the homing of the Z axis; i.e. when the sensor triggers, this is not necessarily (and most commonly) not the position where the nozzle is at Z=0.
```
G29
```
determines the shape of the bed by probing the bed. This will set the shape of the bed with respect to the sensor trigger point as described earlier. The Z-offset (set by
```
M851 Z-x.xx
```
is needed to set the offset between the nozzle and the sensor trigger point (to the bed).
The sequence to determine the offset is:
```
```
M851 Z0; // Set the Z offset to zero height
G28;     // Home Z in the middle of the bed
G1 Z0;   // This will move the head to zero height;
M211 S0; // This will disable the end stops so that you
         // will be able to proceed lower than Z=0
```
```
Now adjust Z height to fit a piece of paper and note the negative Z height (either through the LCD or through an application or
console/terminal
over USB)
Please remember, that a sensor doesn't level your bed, is compensates for the shape, the user should always tram (level) the bed as good as possible with respect to the nozzle print head movement plane! This implies that the user should tram the complete bed as good as the skills allow, all corners, like you would do with a normal Z endstop switch.
```
```
M851 Z-1.23; // Define the Z offset
M500;        // Store the settings
M211 S1;     // Enable the end stops again
```
```
Please note that -1.23 is a fictive value that should be replaced by your own value.
To explicitly answer the raised question, the
```
G29
```
probes the bed by scanning the surface geometry and the
```
M851
```
adds an offset for the sensor trigger to the nozzle (at the center). The offset is required to let the firmware know where the nozzle is with respect to the trigger point. The offset therefor lowers the scanned
```
G29
```
surface, no replacement is taking place. The sketches below illustrate this:
note that the bottom line of the "M851 Z offset" denotes the
```
G29
```
scanned surface


Question:
I'm thinking about building my own 3D printer/Laser Engraver/CNC. Since all use a standard Cartesian axis I wanted to be able to swap out tool heads depending on the purpose. I have everything thought out except the coding aspect of the project.

I currently own a 3D printer and am familiar with some of the coding aspects, gcode, stepper motor moment, axis zeroing, etc; but if I am to build a 3 axis system how do you go about coding it? Are there programs that automatically calibrate all the motors? Can I take existing 3D printer programs and adjust the stepper motor values and build plate area? or do I have to code a new printing program from scratch that can read gcode? For simplicity lets just talk about the printing aspect of the build as I realize that CNC's and laser engravers work on different vector systems. Thanks :)

Answer:
The foundation of any 3D printer is the controller and the firmware. Many devices are based on Arduino type controllers, with stepper motor driver boards either integrated or added as a plug-in component.
Some manufacturers will use in-house or outside resources and develop their own boards and firmware.
You can search for 3D printer controllers and get a pretty comprehensive list of the various devices available for purchase.  Smoothieboard is one device, Raspberry Pi and Arduino as noted above, and others.
There can be found varying "flavors" of firmware to load onto these controllers as well.
The field is exhaustive.
To address your focus regarding the printing aspect, that's one stepper motor per print head/nozzle (usually) and involves calibrating the amount of filament dispensed from the nozzle per unit steps, or more easily understood, amount of steps per unit of filament movement. My stepper motor for the extruder has a planetary gear and moves 100 mm of filament for about 5000 steps.
All of the parameters you've noted are integrated with the firmware. Motor calibration requires movement per step or steps per millimeter to be entered, unless you purchase a turnkey system with the values loaded.
You can adjust many of the parameters from the slicing software, but it's more practical to determine the calibration settings, enter that information into your slicer and proceed with model management.
Look into instructables for others' build projects to see what they've accomplished and the steps involved in such a build. This can give you a starting point for your efforts.


Question:
I have a very dense point cloud (billions of points) of the exterior of a building obtained by laser scanning it with a Leica head.
I successfully subsampled it down to around 500,000 and I'm trying to print the building by first creating a mesh.
I tried using CloudCompare, Meshlab and PDAL, using Poisson surface reconstruction.
However, the resulting mesh is full of holes, mainly in the roofs which have the lowest point density, and I cannot print it.
Is there any algorithm which could use the fact that the point cloud is precisely the exterior part of a geometric thing?

Answer:
The foundation of any 3D printer is the controller and the firmware. Many devices are based on Arduino type controllers, with stepper motor driver boards either integrated or added as a plug-in component.
Some manufacturers will use in-house or outside resources and develop their own boards and firmware.
You can search for 3D printer controllers and get a pretty comprehensive list of the various devices available for purchase.  Smoothieboard is one device, Raspberry Pi and Arduino as noted above, and others.
There can be found varying "flavors" of firmware to load onto these controllers as well.
The field is exhaustive.
To address your focus regarding the printing aspect, that's one stepper motor per print head/nozzle (usually) and involves calibrating the amount of filament dispensed from the nozzle per unit steps, or more easily understood, amount of steps per unit of filament movement. My stepper motor for the extruder has a planetary gear and moves 100 mm of filament for about 5000 steps.
All of the parameters you've noted are integrated with the firmware. Motor calibration requires movement per step or steps per millimeter to be entered, unless you purchase a turnkey system with the values loaded.
You can adjust many of the parameters from the slicing software, but it's more practical to determine the calibration settings, enter that information into your slicer and proceed with model management.
Look into instructables for others' build projects to see what they've accomplished and the steps involved in such a build. This can give you a starting point for your efforts.


Question:
I was working on a model today and I need to make the black surface into a normal surface so that the ship's cockpit is solid. I am unable to select the black surface. I tried using the flip normals feature, but I was still unable to select it. Any advice on how to make it into a solid is greatly appreciated. Thanks. :)

Edit: Here's the link to the file
https://drive.google.com/file/d/1mbTdeeZqhNJx-WlXNqF8mD8QYDSI3Vh_/view?usp=sharing

Answer:
The foundation of any 3D printer is the controller and the firmware. Many devices are based on Arduino type controllers, with stepper motor driver boards either integrated or added as a plug-in component.
Some manufacturers will use in-house or outside resources and develop their own boards and firmware.
You can search for 3D printer controllers and get a pretty comprehensive list of the various devices available for purchase.  Smoothieboard is one device, Raspberry Pi and Arduino as noted above, and others.
There can be found varying "flavors" of firmware to load onto these controllers as well.
The field is exhaustive.
To address your focus regarding the printing aspect, that's one stepper motor per print head/nozzle (usually) and involves calibrating the amount of filament dispensed from the nozzle per unit steps, or more easily understood, amount of steps per unit of filament movement. My stepper motor for the extruder has a planetary gear and moves 100 mm of filament for about 5000 steps.
All of the parameters you've noted are integrated with the firmware. Motor calibration requires movement per step or steps per millimeter to be entered, unless you purchase a turnkey system with the values loaded.
You can adjust many of the parameters from the slicing software, but it's more practical to determine the calibration settings, enter that information into your slicer and proceed with model management.
Look into instructables for others' build projects to see what they've accomplished and the steps involved in such a build. This can give you a starting point for your efforts.


Question:
I was considering printing some pieces for my irrigation system, like tube connectors and such. I am aware that PLA is hydrophilic so I was wondering with what kind of product I could coat the pieces, non-toxicity is a requirement because it will water edible greens.

So, what kind of non-toxic product can I use to coat PLA to make it hydrophobic?

Answer:
Before worrying too much about the hydrophilic properties of PLA, it might be worthwhile to test a fitting.
First, print a fitting and see that the freshly made print is strong enough to carry the pressure of the water, and the compression force of hose clamp you may need to connect the stiff irrigation hose to the printed fitting.
Second, soak the printed fitting in water for month or two, perhaps at an elevated temperature to match the higher ground temperature in the summer.  You could put the part in a closed mason jar and leave it in the sun.  You might add a little salt and fertilizer to the water to simulate ground conditions.
After this aging process, you could test to see if it withstands the pressure of the domestic water system.
You might also measure the ground temperatures where you intend to use the fittings.  I find that PLA has no structural strength above about 150 degrees Fahrenheit (65 degrees Centigrade), and the inability to resist slow plastic may start at an even lower temperature.  [For example, I print structural PLA parts with negative clearances and then dip them in 160 degree F water to soften them.]
If the printed fittings are strong enough but suffer from water absorption, I would either print them of ABS or coat them with an ABS coating.  To make the coating, dissolve ABS in acetone until it is the consistency of thick cream, dip your fitting in the mixture, and allow them to dry.  It will take longer than you think it should to dry, and the solution will take more ABS plastic than you might expect.
ABS is not generally considered to be "food safe", but this isn't a potable water system.  The FDA lists ABS as conditionally food safe, and I would be comfortable using it to irrigate my lawn and vegetables.


Question: Given a large set of data, I was able to create a 3D graph in Microsoft Excel.  How can I create a STL file similar to this graph to create a physical model of this graph?

Answer:
Before worrying too much about the hydrophilic properties of PLA, it might be worthwhile to test a fitting.
First, print a fitting and see that the freshly made print is strong enough to carry the pressure of the water, and the compression force of hose clamp you may need to connect the stiff irrigation hose to the printed fitting.
Second, soak the printed fitting in water for month or two, perhaps at an elevated temperature to match the higher ground temperature in the summer.  You could put the part in a closed mason jar and leave it in the sun.  You might add a little salt and fertilizer to the water to simulate ground conditions.
After this aging process, you could test to see if it withstands the pressure of the domestic water system.
You might also measure the ground temperatures where you intend to use the fittings.  I find that PLA has no structural strength above about 150 degrees Fahrenheit (65 degrees Centigrade), and the inability to resist slow plastic may start at an even lower temperature.  [For example, I print structural PLA parts with negative clearances and then dip them in 160 degree F water to soften them.]
If the printed fittings are strong enough but suffer from water absorption, I would either print them of ABS or coat them with an ABS coating.  To make the coating, dissolve ABS in acetone until it is the consistency of thick cream, dip your fitting in the mixture, and allow them to dry.  It will take longer than you think it should to dry, and the solution will take more ABS plastic than you might expect.
ABS is not generally considered to be "food safe", but this isn't a potable water system.  The FDA lists ABS as conditionally food safe, and I would be comfortable using it to irrigate my lawn and vegetables.


Question:
I just changed my nozzle on my Anet A8 after it was fully used up. When I started printing with my new 0.4 mm nozzle (same as before) my extrusion was VERY bad and inconsistent, even so bad I couldn't continue printing because it would pull the first layer off.

If I compare it to my extrusion before the nozzle switch, it is really bad, even though I tightened everything as before. I am quite sure it doesn't have to do with adhesion to the heated bed since I use tape with PVA glue.

Any advice on how to remove this under extrusion so I can continue printing?

All the specs:

25 mm/s first layer print speed

200 °C nozzle

60 °C bed

PLA filament;

0.4 mm nozzle size

Let me know if there is anything else you need to know.

Answer:
Your good extrusion look also a little bad , and the bad extrusion looks like a big feeding problem. for this you need:
Feeding.- try to tight the presure of the feeder thread, the one that press the filament on the extruder.
Bed Adhesion.- Use between 32° and 38°C if you are using masking tape, on higher temperatures the masking tape becomes to peel off if any border of the printing part is close to the edge of the tape.
Sand the masking tape surface and clean it to be free of dust (eliminate shiny surface) with this is enough to get a good adhesion; I recommend TUK and 3D brands, they are sticky. If you need more adhesion you can spray a little hair spray, just one pass.
Clogged Nozzle.- you need to clean it, on your kitchen stove heat the nozzle until melt the filament, then use some cooper wire (some phone wiring has it) to remove residues inside the nozzle. If posible you can buy a drill bit with 0.4mm diameter to ensure a complete cleaning.


Question:
My Printrbot simple metal's extruder is jammed and I need to heat it up to unjam it. Unfortunately, the printer does't want to connect to my laptop regardless of the program I'm using (Repetier-Host or Cura 15).

Is there a way to use a micro SD card to heat up the printer hotend but not print anything?

Answer:
Sure there is. As you use Cura, you can grab any G-code file (you already have) and use it to set hotend temperature (delete the actual printing part from the file) to get something like this:
```
```
;FLAVOR:Marlin
;TIME:102
;Filament used: 0.0573674m
;Layer height: 0.2
;Generated with Cura_SteamEngine 3.3.1
; M190 S60 ;-> this sets the bed temperature so we can comment it out
; the next line sets the hotend to 200 degrees Celsius
M104 S200
```
```
As every line that starts with a semi-colon is a comment and is ignored by the printer,
```
M104 S200
```
, would be the only line you need in the printout file.
If you're interested in knowing more - look here:
G-codes on reprap wiki


Question:
I want to know how to make a mold of a 3D design in .stl format.

Suppose I have a 3D partin .stl format (for e.g. a cylinder) and I want to make/design a mold for this object (i.e. the structure through which I could make the cylinder). Is there any way to do so? Are there any tools to do so?

My requirement is as follows: I have an .stl file of a design and need to develop the CAD files for its mold. I will then need to 3D print these molds. I would require to add a hole to pour in liquid (resin based) raw material which hardens with time.

Answer:
You can also bring the model and a big box into slic3r, align and orient them (enclose the model in the box), and do a subtract modifier, leaving a hollow where the two intersected. You probably want to do this twice, for a top mould and a botom mould. I've done this, but I don't see any instructions online for it. :(
EDIT: Unfortunately, this would be very tedious. It's much easier to use meshmixer or another publicly available program to subtract one stl from another.
In Slic3r, using another stl as a modifier has no effect unless you are also printing that second stl (normally from another head). So you would have to manually remove all the gcode for the second head. Sorry for the bad advice.


Question: I am a complete noob when it comes to the 3d printing world. I just finished assembling my printer and I plug it into my computer with the included usb cable and nothing happens. My computer does recognize the printer being plugged in but it just says "unrecognized device in com 4". Nothing else past that. Somebody please help me with the following steps that need to be taken to get my CPU talking with my printer.

Answer:
Your question addresses (USB) computer connection, so that will be addressed in this answer. For connection to the printer, you need 2 things (apart from the apparent things as computer, printer and cable):
A working CH340 driver installed on the computer for USB communication with the board,
a piece of software to talk to the computer at a bit transfer rate the printer understands.
The cheap Arduino based boards rely on the CH340 chip for USB communication. You should check whether you have correctly installed this driver. These drivers are erroneous and prone to cause problems. Sometime re-installation works, once did work for me.
The SD card supplied by Anet contains a folder (on my SD card:
```
.\A8\A8资料\Software\CH340G Drive
```
) with the installer file of the driver. Once installed properly, you should be able to connect various applications to the A8, provided you use the correct baud rate of 115200.
All this said,
are you asking the correct question
? Why do you need to connect to a computer, as you can print just fine by putting sliced
```
.stl
```
files (
```
.gcode
```
files) onto the SD card (when inserted in the computer using the adapter) and reinsert the card again in the printer to select the file using the menu buttons of the printer. Printing from SD card is considered safer then printing via the computer over USB as the print will stop when the PC is shut down or crashes.


Question: If I have to make an injection mold (for resin based raw material) using 3D printing, what raw material should I choose – PLA,  ABS, HIPS etc.

Answer:
P20 mold steel is one standard. Hardened parts are required for long life, depending on the service and material (some materials are quite abrasive).
You can get a small number of relatively poor quality shots out of epoxy if it is properly supported by a metal box. Your best bet if you want to include 3D printing in the equation is probably to use epoxy or lost plastic casting from a 3D-printed master. Aside from the requirements of core and cavity with sufficient strength, there are requirements for vents, cooling tubes (bubblers and such like) ejector pins and slides that complicate most real molds. Productivity demands a high heat transfer rate, for very small quantities of expensive parts, thermal design may be less important.
Temperatures and pressures are very high in injection injection molding- high enough to melt the materials you mention, and the pressures are in the 10K PSI range, so a 4" x 4" projected cavity will have a pressure in the 80 ton region.
If you have sintered and filled metal 3D parts they may be suitable, but from the prices I've seen you'd be better off to use conventional machining. Finish is also very important if you want the part to come out of the mold, with hours of semi-manual polishing not uncommon. If you don't have fine surface finish you will need extreme draft angles.
The requirements can be considerably relaxed if you are molding soft parts such as the PVC or TPE overmolds on cables. The pressure is less and the finish less important because the plastic is soft, but the temperatures are still quite high. This is sort of a sub-category of injection molding and specialized machines are used.


Question:
My print popped out from the bed and glued to the nozzle. As the printer was printing next hour or so, a lot of pla was extruded and formed on the nozzle.

I'm wondering what will be the best way to remove pla from the nozzle without overheating wires?

a remark: was trying to heat the nozzle over 180, but I am getting a thermal runout. The pla is hard, I don't want to broke the throat.

Answer:
If you grab the blob with a pliers and twist, all or most of it may pop off.  If not,  heat the extruder up perhaps 10 degrees higher than usual, and wait for the external gunk to soften up and then pull it off.
edit :
Well, if it won't get hot enough, then try using an external source such as a soldering iron tip to cut off most of the mess, then it may be time for exacto knife blades and small files to remove the remainder.
Unless you're a clean freak :-) a little residue around the nozzle doesn't matter - it won't touch your prints and at some time in the future it'll be "cooked" enough to fall off.


Question: I would love to re-use my failed prints by re-extruding the plastic to be used in the 3D printer once again. One thing that stands in my way is finding an effective way to shred the plastic into smaller bits for the extrude to use. What is a good thing to look for to accomplish this? Maybe a really big 'paper' shredder?

Answer:
there is a project called
```
precious plastic
```
and there is a
plastic shredder
, but it is a rather expensive solution.
As I am waiting for parts for my
Lyman extruder
, my plan is to hammer the parts and then process in old kitchen robot with steel working area, an
example here
The paper shredder will be ok as long as you can feed it with plastic.