Question:
I have a 3D printer and I have printed some models with castable resin. When I burn one of these models in the oven and then do the metal casting, the surface of the metal piece is not smooth.

I did a test with a pan. I put a model of wax and a model of castable resin to heat in a pan, and the wax model melts, but the resin model don't.

The resin I have is the following:

What is the correct process to make a correct resin casting?

Thanks for your help.

Answer:
Traditional lost molds.
The reason many jewelers use wax for making the molds for lost mold casting is, that it has (compared to plastic molding materials) a very low melting and boiling point, allowing to create molds with much lower temperature equipment.
A variant of green sand casting is done with materials that very quickly decompose in contact with the molten metal or that burn out after setting fire to them. Very common in this context is foamed styrene. Styrene melts and burns easily so it is easy to use in this way.
PLA has been used in some experiments as a positive and then molten out in a baking oven. It and other printing filaments are usually thermoplastics, so melting them out is similar to wax.
Resin is not soft wax or a thermoplastic.
No, in fact, most resins are a duroplastic, meaning that they don't melt.
If you print a positive from resin and then make a mold from that for lost mold casting, you go the traditional way. But most resins don't melt out the way wax does, and on contact with molten metal don'T evaporate the way wax residue does. You got to properly
burn
out the remains of the cured resin at a higher temperature and for a longer time than the wax as the melting point is much higher - use a proper burning oven. A proper burning oven in this relation reaches something like an email oven (1100 °C) or a clay burning oven (up to 1800 °C)
Putting the molds with the opening down into one of these ovens at high temperature should help a lot. Make sure to put a spacer and a tray below to allow better airflow and get the resin out.
Chemical Club.
Besides heat to destroy the resin, most resins could be solved by very highly aggressive chemicals. Which chemical works highly depends on what the resin actually is - if it is
epoxy resin
it would be the highly toxic CH
2
Cl
2
while
polyester resin
is soluble in isopropanol and sulphuric acid.
Cold alternative?
If your product is to be made of a two-component resin or a ceramic that can be shaped cold and that sustains form, then you might also look at silicone molding. This is not an alternative for most metal castings. Among the very few exceptions is pewter, as PunishedPropsAcademy and Evan&Katelyn
showed in their video
and there are high temp silicones around that could be used repeatedly for pewter.


Question:
I've been having trouble uploading the TH3DUF_R2 firmware to my CR-10.  I've already successfully flashed the bootloader using my Arduino,  but when I try to upload the bootloader I get this error:

avrdude: ser_open(): can't set com-state for "\\.\COM4"

Things I've tried:

Changing the usb drivers

Changing the baud rate

Using a different computers without any other usb devices

My printer is not functional right now with just a bootloader and no firmware, so I'm not really sure where to go from here.

Answer:
You should not look at the relative dimensional differences, you should be looking at the absolute differences. Multiplying the undersized dimensions in percentage with the cylinder diameter gives you a value of 0.4  mm for each cylinder give or take a few hundreds. So, basically your printer works very consistent it is just suffering from a systematic offset.
Basically, the printing process needs to
adjust the X-Y dimensions to compensate for plastic flow effects. An option or setting in Ultimaker Cura to counteract this is called
```
Horizontal Expansion
```
. Slic3r and Simplify3d have similar settings. In Slic3r it is called
```
XY size compensation
```
.


Question: Anyone have any idea how much power it takes to run a Creality Ender 3 3D printer every day for several hours at a time? Like what does it eat up per hour? A rough estimate of power use per hour would be nice, then I can figure out how much it costs me. Can anyone help me?

Answer:
If it is really important to you to know how much you are spending per any given print, your best bet is not to guess,
but to know
how much power you're using. To that end, you could purchase a power meter which monitors your power usage. Given the right one, it can even calculate the cost of the power usage all in one little package. This link,
The 10 Best Electricity Usage Monitors
, should provide you some ideas as to what you might find, but I'm sure there are plenty more out there (NOTE: I have no affiliation to the link provided ... it was just a random one I found through a Google search ... Go Go Google-Fu!).
As 0scar pointed out in his comment, there are just too many variables to try and guess what the power consumption
might be
. If you are looking for a real answer, I believe something along the lines as I've linked above is going to be your best solution to getting a real answer. Anything else is more or less just a guess.


Question:
Has anyone had any luck with printing multi-colored prints with the Palette 2 on an Ender 3? If so, what is your steps/mm for the Ender 3 and your flow rate in whatever slicer you are using? I currently have my flow rate at 100 % and my steps/mm at 104.4, and I believe this is what is causing my Palette 2 to not produce accurate results.

About the Palette 2

Palette 2 is a separate device providing one multi color filament out of multiple single color filaments.

As the Ender 3 does not support multi-colour printing, that's why I'm using the Palette 2. It allows any printer to print in multi color as it adds multi color printing to single extruder printers.

Answer:
On this thread,
Does anyone tried Palette 2.0 on Creality Ender 3 or Ender 3 Pro?
, there are a couple of useful links:
There is a video, albeit for the CR-10
1
, but that should be of help:
YouTube - Setup Guide: Creality CR-10 with Palette 2
;
In addition, this Facebook group,
Mosaic Palette, Palette+, Palette 2 (Pro) Users
, apparently has some users who have paired their Ender 3 with the Palette 2.
However,
with respect to your question about the flow rate and steps/mm
, there isn't much info out there about that, and no one seems to have experienced similar issues, but your issue
might
have something to do with profiles - which, as you haven't mentioned them in your question, it is hard to know if that might be the issue or not.
In the same thread,
this post
, states:
I use it with the Ender 3.  There is a profile in Canvas and Chroma for it also.
This link here,
Chroma for Palette 2
, states that
after
using Cura, you then need to load the G-code file into Chroma v3.1, after having selected the appropriate
profile
. However, if you use Canvas, then there is no need for Cura nor Chroma, as Canvas can slice. This link goes through the whole process for Benchy.
At the risk of repetition, the process for preparing the print, post-slicing, is also given here, from
Multicolor 3D Printing How To: Using the Mosaic Palette+ with the Creality Ender 3
, albeit slightly different from the link above:
Setting Up Chroma:
When you load up Chroma, you’ll be presented with a blank canvas ready
  to be filled with your 3D creations.  In the top left corner, make
  sure that you have the
Ender 3
selected from the drop down menu.
  After this you can click
Load Print
.  From there you’ll be presented
  with your gcode files that you have on your computer.
In this example we will be selecting the
```
butterfly-1.gcode
```
file, and
  clicking
Open
.  From here Chroma will be compiling and arranging the
  settings for the gcode file to be displayed.  This might take a minute
  or more.
Selecting Your Colors:
Once the loading is completed, you will be presented with the 3D
  rendering of our butterfly!  This butterfly will be in 4 randomly
  selected colors by default, but we will be changing this next!  To
  change the colors, navigate to the top of the screen where you will
  see 4 colored circles, and drop down arrows along with each circle.
  These circles represent the colors of each tool head.
To change the color, click on the
Tool Head Colored Circle
, and your
  options for color will appear, we’re going to select
Black
for our
  first color.  After this, you will want to select the
Default PLA
  Settings
by clicking the
Drop Down Arrow
to the right of the first
Tool Head Colored Circle
.
As we make these changes you will notice that the 3D rendering of our
  butterfly will change to our corresponding colors.  Repeat this
  process for the remaining 3 Tool Heads, remember to use the
Default
  PLA Settings
for each Tool Head.
Saving Your Project:
After you have selected all your colors, you will click
Save for
  Printer
in the top right corner of Chroma.  From there, name your
  file, and click
Save
.  You will be then presented with a loading bar
  as Chroma prepares our 2 output files.  One of the files will be an
  adjusted gcode file that has added the purge tower we just modified,
  and the other file will be a file that goes straight to the Mosaic
  Palette+.
Printing Your Project:
Once the files are ready, you will be presented with a screen that
  says “Ready to Print!”.  On this screen you will be presented with the
  files you have created for your project, which for us are the
```
butterfly-1.msf
```
which goes to the Mosaic Palette+ and the
```
butterfly-1.msf.gcode
```
file which is your newly created gcode file.
You will also be presented with “Materials Used” for the project,
  “Number of Splices” for the project, and “Number of Pings” for the
  project.
After this, you will need to turn your Creality Ender 3 on if it isn’t
  already.  After making sure that you have all your
components set up
  and assembled correctly
, then it is safe to begin the printing
  process.
Depending on your specific project will determine how long the
  printing process takes.  But once your printing process is complete
  you will be presented with your
beautiful multicolored 3D butterfly
(or whatever your project was)!  After printing is finished, you
  should let the project cool before you attempt to remove it from the
  tray. Once it has cooled you can now gently pry the project off of the
  tray.
Footnotes
1
The CR-10 is, on a broader level, an Ender-3 with 2 lead screws and a slightly different board.


Question: When filament is too short for the extruder to push will there be a stop in printing on the Ender 3, meaning that I should replace the filament when the end of the filament is near the extruder?

Answer:
The extruder can't push anymore when the filament is past the extruder gear. If your filament has run out to that point, the print will
not
halt but print without a filament, meaning that the print will fail. You need to pause the print in time and then put fresh filament into the printer.
If the end of the filament is cut flat at the end and the new one is flat too, the new filament can push the old one out to the nozzle, reducing the waste to a minimum, if you can live without retraction for the amount of length that has to be used up. You could friction weld the two parts together to alleviate this.


Question: I'm interested in 3d printed reaction chambers, but can't find any good information on chemical resistances of PLA, just vague claims that it "might not be" "because it's biodegradable" or that it depends on additives (likely true, but it would be nice to know if there's hope of finding PLA without problematic additives if the PLA itself is okay). Is there any published research or even anecdotes (which could suggest it's worth spending effort to investigate further) on this topic?

Answer:
As @T. M. notes in his comment, there are many good charts of chemical compatibility with various agents.  Very few (I found none) include information about PLA.  By all means, use search engines to find some information.
But, no data source is as true to your specific needs as is testing your candidate materials with your agents.
As a first test put the agent in a tall thin jar or test tube.  Use a few test filaments so that the ends are dipping into the agent.  Check for signs of dissolution, swelling, softening, or any relevant change in the material's characteristics.  Examine the candidate filaments right away, then after minutes, then hours, and if any material survives, perhaps in days.
Print test objects.  Test them with your agent.  Try until you find something that works.
The online material compatibility tables will help you eliminate materials before testing them.  If it says a material is incompatible, it probably is incompatible.  If rated as highly compatible, it should be tested because the formulation of a filament may not match the material tested for the compatibility tables.  If you are running out of options, try the intermediate compatibility plastics.
Bottom line, use the online information to help direct your search, but you should do your own tests.


Question:
I'd like to buy a new nozzle for my Anycubic i3 Mega because it's not precise enough - it fails to print small details like 1 mm eyebrows.

Currently it has a 0.4 mm nozzle and I'd like to buy a better one but I don't know how to choose one which is compatible with this printer.

If you have any advice, please let me know.

Answer:
According to
Anycubic
this printer uses the E3D V5 type hotend as can be seen from the linked video of the AnyCubic Mega:
The brass nozzle you see is fully compatible with the E3D v6 nozzle and can be found on those typical auction and Chinese websites by looking for "E3D nozzle". They are also available from
E3D directly
, the designer/creator of the E3D hotend family, and other specialized manufacturers like the
Olsson Ruby
. These nozzles have a short nozzle (snout) and are screwed into the heater block with M6 threads.
1)
The smaller the diameter, the smaller the filament traces and the higher the print detail resolution. Note that a smaller diameter causes thinner walls for the same amount of (vertical) walls and may require additional perimeters to get similar strength and rigidity. The maximum layer thickness also decreases, as prints with a layer height above 75 % of the nozzle diameter have very poor quality. As an example, a 0.25 mm nozzle should not print layers thicker than
$0.75 \times 0.25\text{ mm} = 0.19\text{ mm}$
.
As such printing with smaller nozzle diameters increases print time. Also note that a smaller diameter requires more force to push the filament through and
could
use some extra temperature to make the filament more fluid or reduction of the print speed.
Just buy some spare nozzles of different nozzle diameter and experiment what works best for you.
1)
-
The other popular style of M6 threaded nozzles has a long body and long taper (often referred to as MK8 nozzle; they come in two different shapes). While these might work, they extend from the heater block considerably further and might need readjustment of the heater block (
as explained here
):


Question:
We have a fairly new Ultimaker 3 Extended.

When printing ABS with the AA0.8 nozzle and the recommended settings (up-to-date CURA) we receive a very poor wall quality that exposes some kind of pores. I've attached an image of those pores.

I assume those pores are dragged by the nozzle when it moves inwards to print the infill.

I already tried to increase the wall thickness or increase the layer height to 0.3 mm. Are there other settings I might be able to tweak to eliminate those pores?

Answer:
According to
Anycubic
this printer uses the E3D V5 type hotend as can be seen from the linked video of the AnyCubic Mega:
The brass nozzle you see is fully compatible with the E3D v6 nozzle and can be found on those typical auction and Chinese websites by looking for "E3D nozzle". They are also available from
E3D directly
, the designer/creator of the E3D hotend family, and other specialized manufacturers like the
Olsson Ruby
. These nozzles have a short nozzle (snout) and are screwed into the heater block with M6 threads.
1)
The smaller the diameter, the smaller the filament traces and the higher the print detail resolution. Note that a smaller diameter causes thinner walls for the same amount of (vertical) walls and may require additional perimeters to get similar strength and rigidity. The maximum layer thickness also decreases, as prints with a layer height above 75 % of the nozzle diameter have very poor quality. As an example, a 0.25 mm nozzle should not print layers thicker than
$0.75 \times 0.25\text{ mm} = 0.19\text{ mm}$
.
As such printing with smaller nozzle diameters increases print time. Also note that a smaller diameter requires more force to push the filament through and
could
use some extra temperature to make the filament more fluid or reduction of the print speed.
Just buy some spare nozzles of different nozzle diameter and experiment what works best for you.
1)
-
The other popular style of M6 threaded nozzles has a long body and long taper (often referred to as MK8 nozzle; they come in two different shapes). While these might work, they extend from the heater block considerably further and might need readjustment of the heater block (
as explained here
):


Question:
Is there a way to change the use of an extruder port on a 3D printer motherboard to move stepper motors (on y axis) on a 3D printer?

This is for a school project, and we have replaced the extruder with a laser for cutting material.

We were tasked with converting a 3D printer into LOM 3D printer, the laser is set using the fan port, however we still need two stepper motors to move material from one side of the printer to the other after each layer of material is cut.

The mother board we are using is WitBot MKS Gen L V1.0 Controller Board Integrated mainboard Compatible Ramps1.4/Mega2560 R3 with A4988 Motor Driver for 3D.

Answer:
This has nothing to do with the infill overlap, the image you've added looks as if the issue is related to non-bonding perimeters (it looks as if it is in between the 2
nd
and the 3
rd
perimeter), hence infill overlap doesn't apply here. If that is the case look into
this question
.
I've had this same issue, the problem is that if the perimeters do not touch, this is most probably caused by insufficient filament flow which can be a result of a too high of a print speed (or too low print temperature) of the inner perimeters. This is frequently seen when printing PETG. PETG has a limited print speed, the PETG I use (premium brand) has a maximum speed value of 50 mm/s, your values are for some values over that value. That would be fine for PLA, but high for PETG, the question is not clear on the material used for this print (the hotend temperatures hint to PLA, the bed temperatures are rather high though).
If it is not related to the material being printed, these gaps are also explained if the positioning of the nozzle is not correct, e.g. caused by loose belts. This is supported by the comment on the first layer:
where the infill on a first layer would often not reach the perimeter shells


Question:
During my last print I noticed this jumpy behavior during heat up (blue is bed, red is hotend):

So I am wondering about the jumps. What could cause this? I do not think that it is a defunct sensor (it is in both sensors) and I also don't think it is real. Could this pose some sort of hazard as temperature might not properly be controlled?

I use an Anet A8 printer with Marlin 1.1.9 and Octoprint

Answer:
It looks like everything is ok with the real temperature, and it is just Octoprint missing some readings, like Oscar said.
But I think it is unlikely the USB cables fault, the whole print would fail in that case. I think the PI is to busy, maybe due to a Webcam streaming at high rate (try reducing the framerate). Another reason might be if you use a PI Zero W, especially if you transfer data over the Wifi at the same time, since Wifi and USB cause bottlenecks for each other on that board.
PS. I'd comment, but don't have privilege yet.


Question:
I acquired an Anycubic Chiron yesterday. I went through the leveling procedure and I think the level test print came out okay so I printed a 20 mm calibration cube and a benchy. Both of these came out with a sort of spongy consistency.

I have no idea what could be causing this so some advice would be appreciated.

I'm using Ultimaker Cura 4.0.0 and printing in PLA.

Answer:
I would lay odds on it being your filament is moisture saturated. You don't state what type of filament you're using, but to my understanding this is what happens when it is saturated. The water evaporates as it goes through the nozzle, which causes the filament to puff up, which leaves voids in your print.
The print itself looks like it came out rather well. I mean, the edges of the print are solid and everything is clearly defined. This would state to me the slicer and the printer itself are doing their jobs well. You didn't measure it (or leave any hint you did), so I'll assume the overall dimensions are good.
Try a different filament and see if you get better results.


Question:
I am trying to print the 3 jaw lathe chuck on Thingiverse. This specific piece is the scroll.stl, but it applies on every big piece. The print material is (transparent) PLA, that I print on custom glass bed, which is heated by a regular heated bed at 65 °C. However, my print is warping on the external edges of a solid 2 mm for a 85 mm diameter print.

I didn't use the cooling fan. And I don't have an enclosure to keep the warmth inside the printing area. The nozzle temperature is around 200 °C.

What could be wrong?
The printer is a slightly modified Prusa i3 MK2.

Answer:
Several things I've done to stop warping when it occurred:
Use a wider brim.
If the brim isn't sticking, use a higher bed temperature for the first layer.
If the brim comes up only on one side or warping is only on one side, make sure the bed is level.
Slowing down the print will keep you from having as long of a strand cooling down.  This will lower the contraction force and reduce warping.
A hotter bed temperature will reduce the temperature difference between the extrusion and the bed, thus reducing the contraction force.
200 °C is a good temperature for getting PLA to stick.  I've tried lower extrusion temperatures to reduce the temperature difference between the extruder and the bed, but this decreases adhesion to the bed and is counterproductive.


Question: I made a print that involves joining two halves together to create the full model. I decided to use hot glue to bond the halves and on one model, the parts came together slightly skewed. Is there any way to ‘unbond’ the hot glue without ruining the model so I can realign the pieces? Touching the glue gun tip to the hot glue wouldn’t work, as the glue is inside the model.

Answer:
it seems like retraction issue
i would say you should experiment with
retraction length - so it would retract more
extra extrusion after retraction - so the printer could put some material before it will start your next hole :)
unfortunately there is no good guide how much it should retract and how much it should additionally extrude as it depends on "all your printing circumstances" but here is my arbitrary list in order of importance
filament (density - type and producer)
temperature (viscosity - hotter filament flows easier)
nozzle diam (as filament escapes easier through big hole ;)
heat barrier (cooling efficiency - filament should be cool as long as possible up to (or down to) the nozzle)
extruder gearing quality (good coupling makes precise retraction and extra-extrusion)
cooling (fan and duct should cool your printing right after it sticks to the surface)
and one more thing worth to mention
usually the first layer is not cooled which makes whole system hotter (so filament flows easier)
you could experiment with it too especially for big printouts
so
overextrude first layer AND
turn on cooling first layer
it seems like there is a bunch of things you can do to master it :)
good luck - it's definitely manageable


Question:
I'm still new to 3D printing and I want to print something. I expect that I'll mess it up since I find nothing to adjust it but it is now laying around for 4 months and I'm sick of it.

So my question is where do I find Windows software to print something and of course where do I get a 3D model?

I own a Geeetech i3 Pro W.

Answer:
First; find a model!
To print something you require a
model
(usually this is in STL format, look into websites called
Thingiverse
and
MyMiniFactory
for examples). Once you have a model file, you need to make it readable for the printer firmware.
If you can't find suitable model, then you need to design a model yourself (or ask someone to do it for you) or adjust an existing model to suit your needs. "
Good (preferably free) Beginner Software for Part Creation?
" is a good place to start.
Second; use slicer software
For a printer to be able to print the model, the model needs to be sliced into layers. These layers need to be printed at specific speeds, temperatures, etc. Search online and look at the filament packaging (usually the ideal temperatures are on the packaging) to find the ideal temperature for your filament. If you are not using the right temperatures, your print will most likely fail. Programs that are able to slice models are called
slicers
. The most popular free (and Windows compatible) slicers are
Ultimaker Cura
and
Slic3r
(or its
Prusa distribution
).
The slicer produces a printer readable file called a G-code file (file filled with printer instructions for e.g. movement and heating). This G-code file can be sent to the printer using specific printer software (e.g. OctoPrint, Repetier-Host, etc.) but more common or simple is to put the G-code file on an SD card and print the file using the print menu on the printer LCD.


Question:
The original bed surface of my Ender 3 has become brittle and finally cracked, requiring replacement. I'm trying to figure out what the cause might have been to avoid it happening again. It seems to have started after using "flex PLA", which involves both high temperatures (225 °C) and plasticizers mixed in the PLA. Could either of these have contributed to the problem? I'm not sure what material the bed surface is - it's the new one that's removable and held on by clips. If it's PEI, the glass transition temperature is supposedly 217 °C, just above what I use for normal PLA but well below what I'm using for the flex, so perhaps that's the cause?

Image of the damage:

Answer:
The material used for the Build surface is not PEI but a BuildTak Clone that offers adhesion through a rough surface texture. I do not know what exactly is in the composition of the polymer, but I can say that my bed surface needed replacement about 9 months after purchase after I vigorously removed a piece I printed. As a matter of fact, most build surfaces - even PEI - are pretty much going to wear out over time and need occasional replacement. Luckily, a build surface isn't expensive usually.
To prolong the life of the bed surface, I suggest:
check the nozzle distance to the bed, as printing too close can make plastic residue extremely hard to remove.
be very careful when using sharp tools to remove parts - don't let a corner bite into the surface!
don't use a soldering iron or hot air gun on the build platform to remove stuck parts, you'll melt the surface and degrade it
clean the surface at times.
However, replacing the bed is easy enough, as I found out
here
.


Question:
Trying to print a 3D model for my mobile phone, but I see that when printing the sides, being thin, increases the retraction and the recoil seems a little abrupt and makes a coarse sound.

I would like to know if it is possible to know what speed and temperature is recommended to print a model.

In my case I use Simplify3D, and when I'm going to save the file in .gcode format, I see that there are some ranges shown in colors, how does this apply to the models?

Answer:
The first indication for print speed and temperature should be taken from the box the filament comes in. Generally it specifies temperature ranges for the hotend and the heated bed. Sometime, mostly online, more parameters can be found amongst which is the printing speed.
Do note that temperature and printing speed are linked, if you want to print faster you should increase the temperature. But, if you are printing small or thin things you should print slower so that the part cools enough for the next layer. Basically, part cooling is then also important, but not all filament types (e.g. the ones with a high melt temperature like ABS or PETG) like being cooled too much. So you have another parameter to consider.
It is difficult to instruct you to print at a certain speed and certain temperatures as it is highly depending on the filament (e.g. also the filament diameter), the machine type/make and model, extruder setup (direct or Bowden), the print, enclosure, etc.
Because of the many parameters affecting printing, it is usually suggested to calibrate the printer by printing a
temperature tower
or performing
retraction tests
to find the print window for your specific setup.


Question:
I'm wondering if there is some trick to power my OctoPi with the power supply of my 3D printer. I'm using an Geeetech I3 Pro W.

The power supply itself should be able, but the output is as far as I'm aware of 3.3 volts. Not my desired 5 V for USB, it would be a shame if I really would need to buy a new power supply when I have a strong one actually running. My current power supply causes a lot of "Under-voltage detected!" warnings.

After thinking a little about the specs, there are cigarette lighter adapter for cars they use 12 V. Has anyone experience with using that on his printer?

Answer:
Where are you plugging in the USB power to the Pi? If you are back powering it from the data connection, you will bypass the fuses and potentially ruin your Pi or worse. Look at this
wiki
under the power section:
Back-Powering; (powering the Raspberry Pi from a USB hub through the uplink/data port, single cable) Back powering is possible on the Raspberry Pi, but not advisable. Revision 1.0 boards have to be modified to back power, this is due to the 140 mA "polyfuses" that are installed in the USB port circuit. Revision 1.1 boards do not need modifications to back-power, they have replaced the polyfuses with 0 ohm resistors in their place. Revision 2.0 boards do not need modification, they have neither resistors nor polyfuses. It is advised that short (12" (.3 meter) or less) USB cables be used for back-powering a Raspberry Pi. Cable resistance plus connector resistance can quickly reduce operating voltages below the proper range (5.25 V to 4.75 V). But do note that if you do not power the Raspberry Pi in the "official manner", that is through its micro-USB port, but use any alternative way (such as through the GPIO header, the test points TP1 and TP2), but also by back-powering it, you are actually bypassing the Raspberry Pi's input polyfuse protection device! This can have extreme consequences if ever you manage to put more than 6 V on the Raspberry Pi, even for a very short period. As this causes the overvoltage device D17 on the Raspberry Pi to trigger and short the 5 V supply! Without the polyfuse limiting the current through D17, it will burn out, probably melting the Raspberry Pi's enclosure with it, (if you have any) and possibly causing a fire-hazard. It will probably also create a permanent short of the 5 V supply! So be warned, and if you use back power make sure your hub or its PSU has a fuse to prevent this from happening. If not, add your own fuse.
As far as powering the Pi through a 12 V to 5 V converter this will work as long as the current is rated above what the Pi will use, preferably a lot higher. You will also have to consider how this option will cut the power abruptly when you switch the printer off and the Pi will not boot down properly.


Question:
My FDM printer bed moves on the Y-axis and the print head moves on the X-axis and raises on the Z-axis. When printing rectangular objects (a model of Notre Dame in this case), are there print detail quality advantages to aligning the model perpendicular to the X or Y axis, or at 45 degrees? Part strength is not an issue and support is not needed.

Thanks.

Answer:
In short: Not really.
longer version: It depends.
The main culprit of losing details in this case would be the weight and speed of the thing moving. So if you have a heavy X-axis carriage, acceleration and decelerating the carriage won't be instant. Same with the bed (Y-axis).
Another culprit can be slop in the system, so check your linear bearings and belt tension.
Also keep in mind that you are printing on the bed, so the weight of the Y-axis increases while the print progresses. This shouldn't be a problem for small prints, but if your print becomes bigger it can decrease the quality. Another factor is that every print will bend a little the higher it gets, so if you print a tall slender object, don't accelerate the bed too fast ;)
To summarize, for high detailed prints:
Lower the speed
Check the system for slop (tighten belts, and align linear bearings)
Take the lightest axis for the highest detail (keep the weight of the print in mind)
One thing that you can do to test your machine is to test the ghosting on each axis (
https://www.thingiverse.com/thing:277394
).


Question:
I try to print a stamp with flexible filaments. The problem I encounter is that the filament is flexible, but not soft. This leads to small differences in height to parts of the stamp not working.

One solution would be to add a small 'cushion' to add some squishyness to the stamp. I designed the stamp and the 'cushion' but now the question arises:
"Which infill will provide the best uniform squishyness (in one axis)?"

I did a test with cubic infill of Cura, and although it becomes quite squishy, some parts are squishier than other parts of the block.

TLDR; Trying to print a squishy cube, where in one axis all areas of the cube have the same squishyness.

Answer:
As the rubber stamp needs to be soft in one axis for the whole area, you could use an infill that causes the same softness in all directions, but is sliced as such that the stamp experiences the same softness. Alternatively you can use the specific infill types for flexibility, but beware of the orientation:
Concentric
Cross
Cross 3D
First
, to get the same softness in each direction you need to use an infill pattern that has similar/uniform properties (
isotropic
) in all dimensions.
It is suggested to look into the infill type called "
gyroid
" (see question
What are the advantages of gyroid infill?
).
This type of infill
is described as:
Gyroid infill is one of the strongest infill types for a given weight, has isotropic properties, and prints relatively fast with reduced material use and a fully connected part interior.
Second
, since the stamp has relief, slicing the part may cause different infill height. You could look into
Different infill in the same part
to e.g. get a solid infill for under the relief to get a uniform infill for the "cushion".


Question:
I am printing a mechanical part for my printer.

It's a new mount for my extruders and I have been attempting to use BVOH as a support filament so that when my print is done it will cut down on the need to finish the part and possible mistakes.

My problem is I can get the BVOH to adhere to the bed with no problem and no warping of any kind, but I can't get the ASA to adhere to the BVOH supports. I run the BVOH at 220 °C and the ASA at 250 °C with my fan at 10 % and I am using a Flashforge Creator Pro printer which is mostly enclosed.

Does anyone know of a way to get the ASA to adhere to the BVOH?

Answer:
Can you tell by looking at the de-adhesion what isn't sticking?
It may be that printing the ASA at higher temperature is melting the BVOH enough that it doesn't stick, being molten.  If so, then it may be possible to print the first layer of ASA at a cooler temperature, slower if necessary to still succeed at extrusion, with fans blowing.  Then, print the next layer of ASA at a higher temperature, also with fans flowing.
A test might be to print the BVOH, then a layer of ASA, and stop.  Let it cool and test the adhesion.  If it sticks under these conditions, then a better command of the temperature profile may offer a way forward.


Question:
I don't want this to be a specific producer question, but I would like to know if the Sparkmaker is good enough to print small details in OO/HO scale objects.
I'm referring here to objects like furniture, and other house appliances at scale.
I wasn't able to find any visuals with very small objects for this printer.

Answer:
Can you tell by looking at the de-adhesion what isn't sticking?
It may be that printing the ASA at higher temperature is melting the BVOH enough that it doesn't stick, being molten.  If so, then it may be possible to print the first layer of ASA at a cooler temperature, slower if necessary to still succeed at extrusion, with fans blowing.  Then, print the next layer of ASA at a higher temperature, also with fans flowing.
A test might be to print the BVOH, then a layer of ASA, and stop.  Let it cool and test the adhesion.  If it sticks under these conditions, then a better command of the temperature profile may offer a way forward.


Question:
My voltage at the controller at max load is ~11.4 V
(heated bed + motors + hotend). Is this normal?

I'm measuring 11.8 V at the PSU, so 0.4 V -> 5 W lost in the wires.

I have a pretty beefy ~2 mm diameter copper wire that's ~1 m long. Its area is 2.5 mm2. The diameter with shielding is 3.5 mm.

Could there be a bad connection somewhere?

Checked the wire is warm to touch, so looks like it's actually the cause.
Is this normal? Should I go for even bigger wires?

Answer:
Per
this website
it matches the expectations.
Using 13AWG =~ 2.5 mm^2, 18amps, 12volts, 6feet = 2meters (1m back and forth).
Results in 0.4v drop.


Question: I printed parts for a Harry Potter wand with HatchBox Wood PLA, now I want to apply stain. I intended to try MinWax PolyShades wood stain, then noticed Varathane water-based wood stain is available at my local Rona hardware store. This seems a "healthier" option, maybe not as fussy to apply as PolyShades, anyone had experience with this product?

Answer: Wood stains (as opposed to dyes, paints, etc.) work by having large particles that become lodged in the grain of the wood, yielding a result that varies in intensity with the grain of the wood and thereby brings out its beauty. It's unlikely that they will do what you want, or anything reasonable, on PLA that has wood particles mixed into it. You might be able to find some types of dyes that will work. I've used wood dyes on woods that don't take stain well and have had good results, and if the PLA+wood material consists of a significant amount of wood, it seems plausible that wood dyes might work well on it.


Question:
Can any one help me out that how to start a cycle by just using a push button.

Note: Using Marlin firmware, Arduino Mega, Ramps 1.4

I haven't tried altering the Marlin code (as I am new to coding), I was just thinking of adopting this feature as it will be very easy for CNC DIY maker using Marlin code to run a cycle in a loop.

Answer: Wood stains (as opposed to dyes, paints, etc.) work by having large particles that become lodged in the grain of the wood, yielding a result that varies in intensity with the grain of the wood and thereby brings out its beauty. It's unlikely that they will do what you want, or anything reasonable, on PLA that has wood particles mixed into it. You might be able to find some types of dyes that will work. I've used wood dyes on woods that don't take stain well and have had good results, and if the PLA+wood material consists of a significant amount of wood, it seems plausible that wood dyes might work well on it.


Question: Does anyone know how the developers of Marlin decided to name it that?

Answer:
Yes, it probably is totally off-topic, but fun too, so I'll try to get an answer in, before the question gets closed.
The best place to ask would be the
Firmware - Marlin forum
, on RepRap.org.
The question is there now,
Why was it named Marlin?
and I'll update this answer, if/when I get a response...


Question:
Model: Infitary M508

Details: The filament is stuck in the extruder preheated for PLA (the filament is PLA 1.75 white). The extruder's motor works and the filament is in the hole of the extruder (not somewhere else). I took the fan covering the motor apart, to show what is inside, so you might see it on the attached image:

You might also see this video for details: https://www.youtube.com/watch?v=R8rYGhuYWvc

I'm able to pull the filament out, when I uncouple the motor's gear, but it doesn't go through the extruder when I push it in.

What can I do to fix this? Thanks!

P.S. It's the first start of the printer.

Answer:
Unfortunately you're going to have to tear the extruder head apart and clean the nozzle. There are kits like the following (found on Amazon - No affiliation):
This will give you everything you need to clear the nozzle. The only other solution is to replace the nozzle and extruder tube. The filament is stuck in either or both of these parts.
(As an aside ... a wise person <
cough
> @0scar <
cough
> once told me I should keep extras of these parts, as well as the thermister and heating elements on hand. Treat them as disposable parts ... once they're dead, just replace them.)
What you need to figure out though, is why it clogged in the first place. More than likely you tried to extrude filament before the nozzle was up to temperature. If your readout said it was good, then you need to get a no-touch thermometer and check the nozzle for the proper temperature prior to printing to ensure it's all good.


Question: I have been looking to buy a new extruder. One of the options I have seen comes in "right handed" and "left handed".  What does this mean? How can I tell what my current extruder is, so I get the right replacement?

Answer:
This is an example of a right handed extruder setup:
And this is an example of a left handed extruder setup:
I believe that you can can choose whatever one you favor. With the right handed setup, you will be pushing down the red part with your right hand when inserting filament. With the left handed setup, you will be doing the same thing but then with your left hand. Personally, I favor the right handed setup (my right hand is my dominant and stronger hand). But, you should be able to choose whatever one you like! Be sure to check it will work with your printer though (extruder holder & hotend).


Question:
During a print a lot of plastic ended up ripping the nozzle's yellow insulation strap.

Can printing without this insulation around the fusion chamber damage the printer?

If there is no chance of damaging the printer, how likely is it that the prints will be affected by the absence of this insulation

Answer:
No, without the insulation you can print without a problem. I've been printing for years with (cotton or silicone) and without insulation, works perfectly. Although heat radiates from the heater block, I've never experienced issues that it causes overheating of your printed parts.
Note that the insulation tries to contain the heat in the nozzle preventing heat to leak to the surroundings (less energy is used/wasted). As such you may need to do a new PID tuning (certainly when the print cooling fan is incorrectly positioned as such that it cools the hotend heater block), but printing should just work fine if the print cooling fan is in the correct position.


Question:
3D Printers (those who print, not the machine, dummy)!

I haven't been printing in a while, so when I returned to my Monoprice Select Mini VII, of course it had been sprung out of whack. Some of my first prints would not even come out of the extruder until I realized I had some pretty bad (and worse, unnoticed!) heat creep going on. After fixing that issue, it became apparent that many more persisted.

My question for you all is this: In general, what problems should be addressed first when looking at a complete disaster of a print?

I'm not going to specify any singular problem, but I am interested in seeing the "order of operations" for general problem solving when multiple issues exist. For example, "Fix bed height before anything else; this is a common problem that produces multiple others." Hopefully, this can help others with multiple printing issues, too.

Answer:
for sure the answer could be dissertation or even a book because there is no simple way to address "all" issues - it's just to wide area
but as the simple troubleshooting i would list it this way
is your printer alive so is it
working at all (check power, cables)
communicate with the world (check app, drivers, cables)
moving HE and heating HB (check jams, end-points, belts, screws)
is it extruding (check heating, temperature, HE jams, filament path)
if all above is "yes" then
is your printer making printouts and are those printouts
starts and continues (check heating HB, HB adhesion, leveling, cooling)
finished at all (check all above again, stepsticks temerature)
keeping the shape (check screws and nuts, couplings, stiffness, stability, temperatures)
if all above is "yes" then in general you are half way ;)
common issues - printout is
bent or skewed (check geometry, stiffnes, leveling, belts, vibrations, stepsticks temerature)
wrapped or overextruded (check temperature, extruding, printout angles)
underextruded (check filament flow, filament path, stepsticks temerature)
stringy (check temperatures, app settings)
that is the main path i think. all above is more or less applicable to all DIY printers and all prusa clones and all clones of clones ;)
it can go wrong and fork in all possible moments as there is so many aspects to screw...


Question:
I have a Tevo Tornado that I've outfitted with an official BL-Touch auto level sensor. I can see the bed probing run, and I can see the Z axis slowly adjust during x/y moves, so it's doing something. However, you can see that there appears to be a systematic tilt:

Any ideas what could be causing this? The bed, gantry and print head is tight, no wobble. Here's my start code:

G28 ; home all axes
G29
G1 Z5 F5000 ; lift nozzle

I have mesh leveling enabled with a 5x5 grid and correct probe offsets. The bed itself is on PETG printed standoffs instead of springs to eliminate any jitter.

Answer:
The problem with the Tevo Tornado design is that the design is as such that the Z-axis is powered by a single stepper (under the assumption that you have not added a second Z stepper).
This means that the level relies on the rigidity of the X-axis assembly, more specific the play on the guide wheels. Apparently the BL-Touch level determination suffers (the up and down movement while probing) from this design as can be seen from the tilt around the Y-axis direction. This effect causing the tilted level plane is called
hysteresis
. Now that the Z-axis moves up and down you experience much more problems than using a mechanical switch. The effect is more pronounced when the mass of the hot end carriage is furthest from the Z-axis lead screw.
Note that an extra stepper can also cause tilted level when the second stepper does not move in sync (e.g. missing steps). In such designs, a single stepper (geared) belt driven 2 lead screw has better performance in that respect.


Question:
I have been looking at getting some painters tape to use on the glass plate for better print adhesion, and everything I read suggests the blue painters tape, such as this:

However, this white tape is considerably cheaper:

This looks like normal masking tape to me.

Is masking tape ok, or is the blue painter's tape preferable? If the latter, then why is that so? What is so special about the blue tape? Is it a different material?

Answer:
Of course, I don't know what kind of tapes you have. My experience with blue tapes is, that they seem in general softer and "nicer" than white tapes. Their structure appears denser and they seem to have longer "furs" while the white ones are "dryer" and "sharper"
This surface makes the blue tapes I sourced more suitable as the molten filament catches more furs.
Here are magnified photos of my comparable tapes. Unfortunately, my microscope is pretty lame but at least we can take a look on closeups:
This comparison shows the lower density of my white tape better:
to complete the picture here goes angle photos which reveals some more details
above shows that this white tape is made out of flat plastic fiber as they shine when illuminated from different angles
this could lead to another question
is such tape melted in any way in contact with extruded filament?
worth to analyse...


Question: I’m designing a part that will need to be autoclaved—it will be under steam at 121°C for about 15 min per job and I will want it to be able to go through the autoclave repeatedly. I ran a test PLA part through the autoclave and it warped noticeably; based on their glass transition temperatures, ABS (105ºC) and PETG (80ºC) would probably also not hold up. For a consumer-grade FDM printer, what filament materials that could be used for parts that could be autoclaved?

Answer:
It might seem that common 3D printer materials such as PLA and ABS should be capable of being autoclaved—unfortunately. However, although their melting temperatures are higher than autoclave temperature (typically 121ºC), their glass transition temperatures are below that limit so they can warp or undergo creep deformation.
Sterilization of numerous plastics is described
here
, with PLA, ABS, and PET all being described as "poor" for autoclaving. For each "good" material on that list, I looked for filament by Googling and consulting material guides from
Prusa
and
Matter Hackers
.
Polypropylene (PP) or acetal (POM, also known as Delrin) are the best choices. Filament is available for PEEK, PEI (ULTEM), FEP, PPSU, and PPS but these filaments are expensive (>$100/kg) and require high extruder temperatures (>300ºC).
In contrast, PP is about $50/kg and uses an extruder temperature of 254ºC; POM is similarly priced and uses an extruder temperature of 210ºC. Nylon (depending on the exact type) and HT-PLA may also be worth considering.
"High temperature" filaments are not worthwhile for this application. Again, they're expensive and, more significantly, do not work well with consumer-grade 3D printers. For example, the upper limit for a Prusa i3 MK3s is about 280ºC—the thermistor only is good up to that temperature. Higher temperatures would require swapping out sensors and modifying firmware and building an enclosure.
It's been done
. Printers designed for high-temperature filaments easily cost
thousands of dollars
.
This question was previously asked on
Reddit
a few times
but this analysis is more comprehensive.


Question: Can I use three-phase stepper motors with pololu style stepper drivers? If not, what kind of drivers support three-phase motors?

Answer:
3D printers typically use bipolar two-phase stepper motors, and it is possible that Pololu-style carriers for stepper-motor drivers only support such motors.
Certainly, drivers for three-phase stepper motors exist, for example, the Trinamic TMC5062, but I cannot find any Pololu-style carriers for this chip. Even if a Pololu-style carrier can be sourced, it is not certain that existing 3D-printer firmware can be configured to control it.
If you are thinking about re-purposing some three-phase motors, I would advise that you purchase standard bipolar motors, instead. Bipolar two-phase motors suitable for 3D printing are not that expensive.
Trinamic TMC5062


Question:
I've been playing around with PETG for the first time, and everything seemingly worked right just from the start - clean prints, no stringing, no bed adhesion problems, no warping or dimensional accuracy problems, etc. As expected it prints a lot like PLA, and as expected, it's less brittle/stands up much better to crushing/impact, except that it's really brittle when it comes to inter-layer adhesion. Vertical cylinders that were fairly strong in PLA just snap with no effort as PETG.

My particular PETG filament is Sunlu, with recommended print temperature 230-250 °C. I started out with 235 and am now using 250, which does somewhat better. I've used layer heights 0.125 - 0.2 mm.

Are these kind of results normal? Is there anything I should be doing to get better adhesion between layers?

Answer:
What you describe is usually the result of using a too high of a part cooling fan rotational speed. Like ABS, PETG doesn't require much cooling (if needed at all that is). If you do cool too much, layers and perimeters do not bond optimally (you can get string cheese like printed parts on failure).
Why should you use cooling for PETG?
Cooling helps cool the deposited filament on small cross sectional parts. If un-cooled, the printed part picks up too much heat and will deform or sag out.
In such cases, reduce cooling to 40 % to start with (another option is to print more parts or increase minimal layer time). Note that there are so many print cooling fan constructions, some more effective than others, so you need to tune the print cooling fan speed to your setup. E.g. for an Ultimaker 3E I get good results at 50 % fan speed, for other self-build printers with effective part cooling solutions, 40 % works best (printed several kilometers of 2.85 mm PETG). First few layers don't need any cooling at all.


Question:
After a few months of printing with my Prusa Mk3 (with plans to get a second one soon), I have been wondering about making my third printer a home-built one was a larger print bed than the Mk3. One thing I wondered about is perfectly expressed in the title question.

Are there practical reasons to not use a stepper motor with lead screw for the X and or Y axes?

I am certainly happy with the GT2 belts used in my current printer, but I wonder if the design might be simpler with lead-screws on all three axes.

Answer:
Cost would be the primary reason.  You can engineer a belt driven system that will be equally accurate, faster, and with longer travel for a lower cost.
Lead screws are comparatively expensive. The cost differential dramatically increases with length of travel and speed with equivalent accuracy.
Lead screws do have a significant advantage of being able to carry a much heavier load while maintaining rigidity which is important for something like a CNC mill but isn't as relevant for 3D printing.
This is on the assumption when you say:
Are there practical reasons to
not
use a stepper motor with lead screw for the X and or Y axes?
you meant that you are still planning on using stepper motors but considering a lead screw vs. belts.


Question:
I have two Tronxy 2.0 V5 Marlin boards that reboot whenever heat is applied to the bed. The bed has been swapped (because I thought that was the problem) for a new shiny one. The thermistors, too, of course.  The same boards (both) work when the beds remain unheated (setpoint = 0 °C).

Any ideas what might be causing this, or what I might do to figure it out?

Note: I really have no idea which Tronxy board this is;  the "2.0" is stenciled on the board, so that's all I can figure out. I shamefully admit I tagged it with Tronxy x1 to see if I could generate any interest, and because a "Tronxy" tag is not available.

Answer:
It sounds like a power-related problem. Always use an external MOSFET to drive a heated bed, and consider investing in a decent power supply. Inevitably, the Tronxy PSU will be barely adequate.
Edit: I've just noticed the
tronxy-x1
tag. Be aware that the stock (60 Watt) PSU for the Tronxy X1 cannot power a heated bed (the printer does not have one). Trying to do so will overload the PSU and cause an immediate reset.


Question:
I've got some curious marks on my heatbed.

It appears to be from my black Sunlu PLA+ (I can just feel it if I scrape my finger nail over it) but I can't scrape it off with the metal spatula.

When I try and print over it the filament won't stick.

Any suggestions as to what it is and how you get rid of it?

Answer:
Edit: As Trish noted, apparently Prusa printers don't ship with Buildtak stickers like the other printers I've used, so this is probably a bad idea in your specific case. For others reading this, only do the sanding shenanigans with buildtak or other stickers that you can easily replace and don't mind wearing down over time.
Used to happen to me printing PETG on Buildtak. I ended up using a medium grit sanding sponge to remove the PLA layer. Related, you might want to grab some 1k grit sandpaper for the same reason, it does a great job of freshening up your build surface once builds stop sticking well.


Question:
I now own the Prusa3D MMU2.  The benefits, costs, and experience others have had is well documented.  I am interested in rebuilding my large, home-designed delta machine to be multi-material, and don't want to overlook strategies I haven't considered.

My original implementation used an E3D Kraken as the hot-end, and handled the inevitable delta tilt by adding two additional degrees of freedom to the head to lower the selected nozzle to the bed.  I've been through three generations of mechanisms, and I think the third will work.

But, I feel that I am not seeing obvious and better alternatives.

So, the question:  Through what methods and mechanisms can a multi-material (different polymers, different temperatures) FDM printer operate, and are there available designs or examples of best practices for those methods?

Answer:
One of the easiest ways that I've seen, which I'm a fan of, is simply putting Y splitters on your Bowden tube and having multiple feeds to a single hot end. The main benefit is that you only need a single hot end, so you don't have to worry about extruder offset or alignment or anything like that, but you do have to worry about material blending somewhat. Basically you end up needing to build a "purge tower" next to your printed items that you use to transition from one material to another.
There's the Diamond hotend setup that basically moves the connections into the hotend itself, which reduces the size of your purge tower but increases the risk of burning if you're trying to print with materials with vastly different printing temps, like PLA and PETG.
You could also have swappable hotends but that requires you to be there to manually swap the print head twice per layer. Don't recommend.
Unfortunately there's only so many solutions to the multi material problem, either you put multiple materials through a single hotend, or you have multiple hotends. I'm a fan of the single hotend approach personally, especially on deltas where weight and space are at a premium and alignment becomes problematic.


Question: I read that PTFE starts to deteriorate past 260 °C. Does that mean heating to 250 °C is no problem at all, or will that destroy the PTFE material over time to?

Answer:
Degradation starts at 260 °C and shifts towards full blown decomposition towards 350 °C. 250 °C is technically fine, but you should keep in mind that you've got little to no wiggle room for error at that temperature. Your thermistor and board may not be accurate enough to guarantee you'll never overshoot that temperature, and the way 3D printers often handle temperature adjustment exacerbates that risk. You
can
print at 250 °C, just be aware you've got basically no margin for error.


Question:
I need to cool some liquid (250 °C) while it’s flowing through a tube which has to be able to bend and flex.
My idea is to make a flexible tube with a second tube spiraling around it through which coolant will flow.

I’d like to 3D print this tube if possible so I wonder if there is some printable filament that:

doesn’t melt at 250 °C

is flexible enough that it can print some tube that can bend (bending radius of 30 cm)

optimally also has good heat conductivity

Is there any 3D printer filament available that has these properties?

Answer:
3D printing nerd showed a couple of filaments that fits this in his latest video "Printers at RAPID + TCT 2019":
Firstly a
Nylon 6 high temperature filament
:
Another part of the video shows another flexible print, created on a four axis 3D printer, using
TPU filament
:


Question:
Given a 3D boolean array representing voxels, how can it be converted to a 3D-printer-ready file?

The end-goal I would like to achieve is to print the 3D shape that the numpy array represents (True coding for fill this voxel, False for leave it empty).

For example, the array

[
    [
        [T, T, T],
        [T, F, T],
        [T, T, T]
    ],
    [
        [T, F, T],
        [F, F, F],
        [T, F, T]
    ],
    [
        [T, T, T],
        [T, F, T],
        [T, T, T]
    ]
]

would encode a level-1 Menger sponge.

Answer:
I agree with the use of OpenSCAD, but since it is difficult to program in OpenSCAD, I would use
SolidPython
, which is a front end for OpenSCAD with the full programming capability of Python.
In the alternative, you could use any programming language to decode your arrays and generate the OpenSCAD code for the little network of cubes (or voxels).
The final possibility is to generate an STL file directly.  I've helped someone do this, but we found the rules to be a little non-intuitive.  We used mesh tools to check out results, both by looking for error messages, and by displaying the result to see if it looked as we intended it to look.


Question:
When I print with a 0.4  mm nozzle I have no problem with stringing at all but because I need a more detailed print I must use a 0.25 mm nozzle.

I use Ultimaker Cura and an Anycubic i3 Mega.

What i tried so far:

Enable/Disable Z hop

Tried different retraction distance and speed.

Tried with lower temperature

Different wall thickness

If you have any suggestion please let me know.

Answer:
First, you should change the
nozzle diameter
setting, not just the line width setting, in Cura. Both are involved in determining extrusion. Line width can be less than or greater than nozzle size, but setting it much larger or smaller is not going to work well.
I suspect your main problem, though, is print speed. The area of the 0.25 mm nozzle orifice is only 39% of the area of an 0.4 mm nozzle orifice, bounding the material extrusion rate
at best
at 39% of what you could get with the larger nozzle (in practice it will be even lower due to complex fluid dynamics, probably much lower), but at the same linear print speed with narrower lines, you'll be extruding (or trying to extrude) 62.5% as much material per unit time. Now, if that much material can't actually make it out of the nozzle, pressure builds up between the extruder gear and the nozzle, and stringing is the result.
So, try lowering the print speed.
A lot
at first. If that solves the problem, gradually increase it until you find the limit. Increasing retraction and temperature may help you push it a little further. See my question and self-answer on stringing with flexible filaments, which might give you some ideas on other things to try:
Avoiding stringing with flexible filament


Question:
What grease to use on linear rails to make them stick as little as possible? I've tried so far:

WD40 (let’s not start a discussion about that please),

silicon spray and

some bearing grease called ‘motorex’,

but with all of them the rails stick quite much and don’t slide as easily as I’d hope.

Can someone recommend some good grease for linear rails (specifically the hiwin type, 12-15mm)?

Answer:
Don't use grease
, it is better to use a
light oil
to lubricate the rods.  A light oil will help flush out any dust and filament debris, grease will trap it.
I've used both light machine oil (like used for sewing machines) and PTFE based spray (Teflon). Grease is thick and will collect and trap dust and particles more easily than light machine oil.
Even high-end consumer printers use light machine oil, e.g. the Ultimaker 3 Extended I got came with a bottle of light machine oil for the linear guide rails. Their advice is to regularly add a drop of oil on each shaft once in a while (how frequent depends on how much your printer prints).


Question:
I just updated my Maker Select Plus from the stock (I believe RepRap-based) firmware to Advi3pp, which is Marlin based. The printer starts up and everything seems okay, but I haven't actually tried a print yet and there was a message during the upgrade about deleting incompatible settings.

What do I need to do to recalibrate the printer following the firmware upgrade?

Answer:
If it is Marlin based or RepRap based, many parameters are stored in EEPROM memory. A G-code command
M502: Read parameters from "configuration.h"
would reset all parameters that can be changed to their default value as defined in your configuration file. Don't forget to follow the
```
M502
```
command with a
```
M500
```
command to store the loaded parameters to EEPROM. This would overwrite all previous settings.
From the linked source,
```
M502
```
:
This command resets all tunable parameters to their default values, as set in the firmware. This doesn't reset any parameters stored in the EEPROM, so it must be followed with M500 if you want to do that.
You can send these commands over a terminal interface to the printer using applications such as Pronterface, OctoPrint, Repetier-Host, and probably many more, or store the commands in a G-code file (e.g. a text file with a
```
.g
```
extension) and print the file using an SD card.


Question:
How can I print an embossed image in a concaved shape?

Like a big saucer. I will use this an a mold for a project.

So far I've found lots of software with huge spread of features. It's sort of overwhelming. There is lots of ways to create images into 3D printable objects but to add the extra step and concaving that image is harder to find out.

How would you do it? I'm open to suggestions.

I'm new to 3D printing and would really appreciate the help.

Answer:
What you describe, sounds like you want to create a lithophane; a pattern etched or engraved on a thin translucent base material (in your case a bowl) that can only be seen clearly when backlit with a light source behind it. Apparently you want to use it for another purpose.
Special software and or scripts that transform the image to the base material exist. An example is e.g.
this sphere which becomes a globe when lit from the inside
. Recommending a tool for creating such bowl is a little
out of scope
as these types of questions become outdated very quickly as technology changes or tools cease to exist. With the provided information you should be able to find software that is able to provide what you want to do.


Question:
I am searching for a Linux software to control the 3000 mW laser engraver depicted below. It's a common model you'd find on AliExpress, Banggood, etc. under different brand names.

I have already tried nejePrint, LaserWeb, and EzGraver, but they don't work. Any ideas?

Answer:
A program that lists as functional with Linux is
Lightburn
. It's new to the laser engraving world and supports GRBL type controllers as well as Ruida brand and possibly a few others. If you can determine your controller, you're a step ahead of the game.
Directly from their site:
LightBurn
LightBurn is layout, editing, and control software for your laser
  cutter. With LightBurn you can:
Import artwork in a variety of common vector graphic and image formats (including AI, PDF, SVG, DXF, PLT, PNG, JPG, GIF, BMP)
Arrange, edit, and even create new vector shapes within the editor, with powerful features like offsetting, boolean operations, welding,
  and node editing
Apply settings like power, speed, number of passes, cut order, brightness & contrast, dithering mode, and much more
Send the result directly to your laser cutter
LightBurn is a native application written for Windows, Mac OS, and
  Linux.
I'm a satisfied Lightburn user, not a company representative.


Question:
Recently on one of her videos a YouTuber stated that prints from large format printers are more brittle than if you were to print them in parts and glue them together. This seems to contradict the testimonials from the customers of a large format printer, who say that they get good prints from those printers (which print have a print area of a meter square).

Would a print form a larger format printer be more brittle than a print made of smaller pieces super glued together?

(with all other aspects being equal e.g. the nozzle, the temps, the material and the shape of the object).

The YouTube didn't cite any source information to back up her claim.

Answer:
If you break up a large piece into multiple smaller pieces and properly glue them together, you basically add stiffeners (as a result of printing walls). This could lead to a more stiff model; this might have been confused by calling large prints more brittle opposed to constructed models.
If printing is conducted at similar conditions on large printers, there shouldn't be a reason why the model becomes more brittle unless the conditions aren't the same. But that would be true for printing at small printers too, e.g. if one print was printed in a draft.


Question:
I want to print a flowerpots, for advanced watering system.

Plants are going to be eaten.

What is the most suitable material, when we consider the fact, that we do not want to just make forms and do clay flowerpots(which may seem most healthier), but having them directly printed.

What are the temperatures that makes plastics emit dangerous components in surrounding water, and what are those components?

Is there some "totally safe" material out there? I was thinking of PLA or PETG, because I've already heard that ABS is not safe for edibles.

Answer:
If you break up a large piece into multiple smaller pieces and properly glue them together, you basically add stiffeners (as a result of printing walls). This could lead to a more stiff model; this might have been confused by calling large prints more brittle opposed to constructed models.
If printing is conducted at similar conditions on large printers, there shouldn't be a reason why the model becomes more brittle unless the conditions aren't the same. But that would be true for printing at small printers too, e.g. if one print was printed in a draft.


Question:
I'd like some advice regarding defects on my print :

Here some details :

Printer CR-10 S, nozzle 0.4

Material PLA

Bed 60, Hotend 215, 50 mm/s speed

SLiced with cura 4.1, 5 walls (i can provide more detail of the profile if needed)

Layer height 0.1

modeled on fusion 360

The surface where the defect sits is actually tilted 45 degres

Thanks !

Answer:
If you break up a large piece into multiple smaller pieces and properly glue them together, you basically add stiffeners (as a result of printing walls). This could lead to a more stiff model; this might have been confused by calling large prints more brittle opposed to constructed models.
If printing is conducted at similar conditions on large printers, there shouldn't be a reason why the model becomes more brittle unless the conditions aren't the same. But that would be true for printing at small printers too, e.g. if one print was printed in a draft.


Question: I am working with Ender 3 Pro and in menu it has an option to cooldown. Is there any need to cooldown 3D printer before shutdown or can I just shutdown without cooldown?

Answer:
Depending on what material you print it it most likely a good idea to let the hotend cool down before shutting off the printer (fan).
For example if you shut down the printer right after you print a PLA part, at 190 - 220 degrees Celsius, your hot end will still be that hot and will suffer heat creep without the fan running. The next time you fire up your printer the hotend will be jammed and you will need to clear it before starting a print.
This is obviously situation dependent but in most cases you should let your hot end get below the TG (glass transition temperature) of the material before turning off the printer.


Question:
A fillet is like a rounded corner but on the inside of the corner.

Does it make a difference (structurally) to use fillets on a 3d printed part?

Answer:
If your part needs structural support, then the word is:
absolutely
. Fillets provide the added support when you need it. If your part has a meeting line which is sharp - 90° (or perpendicular), there is a natural
stress riser
in your design. This is a weak spot where a crack can form. If strength is needed and the fillet won't interfere with the design, it's definitely something you should include with your part.


Question:
In regards to a part that I'm having printed remotely (by two processes:- stereolithography and laser sintering), I've been advised by the 3d printing company that 'the triangulation of the file is rather rough'.

In this particular instance, it probably doesn't matter, but for the future, are there any tips to improving 'triangulation' when generating forms in AutoCAD?

Note, AutoCAD's FACETRES variable is set to 10.

Answer:
The phrase "triangulation of the file is rather rough" is somewhat vague, but one can interpret it to mean that the surface is what is considered "low poly" in the 3D modeling world.
From
Thingiverse
, this low poly fox shows an intentionally reduced poly surface. I'm not suggesting that your models appear this distorted, but it may give a hint to what the service is referencing.
Consider to load your model into a program such as Meshmixer, which will show you the triangles in 'W'ireframe mode. If there are few triangles over a surface, you can get the aforementioned effect.
Meshmixer also allows you to increase the mesh count, possibly improving the surface and satisfying the requirements of the printing service.


Question:
This video brought to my attention the 8 mm lead of the Ender 3's Z axis screw, which seems like an exceedingly bad choice from a standpoint of accuracy with respect to common grid alignments in the Z direction. In particular, with the stepper having 200 full steps per rotation, the 8 mm lead consumes all the powers of two out of 200, leaving 25 full steps per mm - and 25ths of a mm are not a typical unit that layer heights/feature heights are going to be in. It seems like a 5 mm lead would be ideal, giving you 40 steps per mm, evenly divisible by 3 powers of 2 and one power of 5, for exact tenths and exact eights.

Is there a motivation behind the choice of 8 mm lead? Is this common for other printers, and are there printers that use a 5 mm lead, or 5 mm replacements that work well?

Answer:
I've not seen trapezoid lead screws with 5 mm lead, you can get 5 mm lead ball screws though.
On one printer I use 4 mm lead screws to get native 0.02 mm resolution (so 5 full steps for 0.1 mm, 10 for 0.2 mm, etc.). I also geared down 8 mm lead screws with a 2:1 ratio (e.g. to use a single Z-stepper driving a belt that drives 2 lead screws), works fine.


Question:
I am printing a small cylinder, but when the object is finished, it's smaller than the measures I used when create the model.

I used thincerkad to make a simple model, the measures are:

width: 90 mm

height: 2 mm

After the print was done, the actual dimensions were:

width: 70 mm

height: 2 mm

Pictures

First attempt

The smaller object that's in the drawn circle was the first one printed, the dimensions I used were:

width: 110 mm

height: 2 mm

Then I printed it again, and the result was:

Answer:
Are you using the stock firmware of your printer? Sounds like to me that you have 16 tooth pulleys and your firmware is set to 20 tooth i.e. 80 steps per mm
The calculation behind the steps per mm is
$\frac{\text{Steps per Revolution} \times Microsteps}{Teeth \times Pitch}$
. The reason for this is that one revolution of the pulley will move the belt the number of teeth times the pitch of the belt. Now take the total number of steps, Steps per Revolution times microsteps, and divide by the distance moved giving the steps per mm.
In
$\underline{most}$
hobby 3D printers you have:
1.8 degrees steppers which equals
$\frac{360}{1.8}=200$
steps per revolution , Less common is 0.9 degrees steppers
$\frac{360}{0.9}=400$
GT2 is the most common belts now which have a pitch of 2mm
The two most common pulleys are 16 tooth and 20 tooth,
Depending on what stepper drivers and or configuration you have
A4988
$\to$
16 microsteps
DRV8825
$\to$
32 microsteps
Trinamic
$\to$
16-256 mircosteps
In your situation I believe you have a 1.8 degree stepper with 16 microsteps, a gt2 belt, and a 16 tooth pulley. Which means your XY steps per mm should be
$\frac{200 \times 16}{16 \times 2} = 100$
. While your firmware is expecting 20 tooth pulleys, yielding
$\frac{200 \times 16}{20 \times 2} = 80$
. This would result in your prints being
$\frac{100-80}{100} = 20\%$
smaller, which explains your results with the circles.
Generalizing, the steppers, microsteps, and pitch don't matter. To go between 16 tooth pulleys to 20 tooth, multiply by
$0.8=\frac{16}{20}$
. From 20 tooth to 16 tooth, multiply by
$1.25=\frac{20}{16}$
.


Question:
I'm not talking about making something that's outright disproportionate of course. I've been working in Blender and I've use Absolute grid Snap to snap my vertices to the grid. The problem is that it (didn't seem) to always work perfectly for centimeters, and seemed to work better for meters.
(edit: I've learned what the problem was and it was simply the placement of the vertices in side view, being at  slightly different elevations. I'm going to emphasize that the difference was very slight. It was just enough to show up in the measurements. When I switched from front view to side view I was able to adjust the elevation to the grid and that fixed the problem.)

Answer:
It depends on what you're working on. If you're producing mechanical/functional parts (even if that just means having to connect to one another or to some non-printed part), 3 mm (0.3 cm) error is almost surely going to prevent them from working. Even 0.3 mm error might be a problem.
If you're doing standalone prints that don't have to interface with anything else, e.g. art, non-articulated figurines, etc., then it becomes just a question of what's visually acceptable, and that's a matter both of scale and of the detail level you want. For typical tabletop-RPG scale, for example, most of the acutal visual features are going to be smaller than 3 mm, so that much error is not going to work out. It might work for large busts, though.
In any case, I would recommend trying to solve the underlying problem. Either change your grid snap, or work at a larger scale and just scale down the final model.


Question:
I've always been wondering about the actual accuracy of 3D printing devices. When looking for the perfect machine to buy, I looked at the speed, price, filaments supported etc, but also accuracy. I once asked somebody who could give me some advice on what to look at.

One of the things I was told about was that many printers don't necessarily have that crazy precision of 0.05 mm (50 micron). Another person told me something different - he said most of those printers actually were capable of putting out 50 micron layer height. How is it really?

Another thing is that the official slicers for those machines also claim that this precision is real, for instance the PrusaSlicer v2.0.

There are many high-end, very expensive machines and even they sometimes claim their resolution is worse than 50 microns.

Answer:
One of the things I was told about was that many printers don't necessarily have that crazy precision of 0.05 mm (50 micron). Another person told me something different - he said most of those printers actually were capable of putting out 50 micron layer height. How is it really?
Both things you've read are completely correct.
Most printers are capable of 50 micron layer heights. However, layer height does not equal "accuracy" or "precision". The layer height specification is a useless marketing term that you should ignore; layer height is to 3D printers what dynamic contrast is to monitors.
All FDM printers are inherently quite bad at producing parts with tight tolerances. The filament extrusion process introduces lots of variables that are hard to control: the diameter of the filament may vary, there is a delay between feeding filament into to the extruder and it coming out, and the gooey filament that comes out of the extruder behaves in unpredictable ways.
Nobody has figured out how to quantify "accuracy" for 3D printers in a way that correlates with the quality of the finished parts. It is impossible to tell which printer produces "better" or more accurate parts from the specification sheet of a printer.


Question: In 3D printing firmware and slicers, jerk settings are expressed in units if mm/s. This is contrary the physical definition of jerk, which is in units of mm/s³, being the second derivative of speed with respect to time (or the third derivative of position). What is the reason for this discrepancy and how does one interpret jerk in this contect?

Answer:
The jerk setting in 3D printing G-code and firmware represents a concept similar to, but distinct from, the physical definition of jerk. Rather, it's a [limit on] instantaneous change of speed.
Mathematically, one way to make sense of this is to think that, rather than being the second derivative of speed with respect to time, this "jerk" is the entire remainder of the first-order expansion of speed with respect to time - it corresponds to the second-order term
and all higher order terms
. Such terms cannot be combined just as coefficients, since they all have different units corresponding to different powers of time; rather, they can be combined only
with their corresponding powers of time
, in which case the resulting unit is mm/s.


Question:
ABS is a very strong material, but it also has some downsides. One of them, which is the necessity of having a printer with enclosure, completely discouraged me from using it, as it would be a waste of money. This is quite sad, because I cannot make prints that will be able to withstand a large load of tension without breaking.

Is there any way to print ABS without any enclosure? Maybe there are several types of this material and some are easier to print?

Answer:
There is no requirement for an enclosure when printing ABS. Like many things in FDM, there are improvements to be made, but there is a scale of what is possible.
A heated bed is much more necessary (for similar reasons, the thermal expansion is significant and without a heated bed you have very high risk of warping).
An enclosure is important for high quality, large ABS prints. Otherwise, a warm location which is free of drafts will be fine, particularly for parts which are only a few cm high.
If you're not using an enclosure, the part cooling fan should probably
not
be used to print ABS. You should also be aware that ABS tends to generate more noticeable fumes than PLA (although this varies with product, and how sensitive you are).


Question:
My anet A8 stepper drivers get very hot after some time printing, so I decided to install a 5V fan to cool them down. I had the idea to get a 12V to 5V regulator to connect a 5V fan, but then i found this image:

(source: lokspace.eu)

It looks like the Anet A8 has an ICSP and Serial header that can deliver 5 or 3.3 V directly from the board. Is this correct? If it is, how many amps can i get from this pin? Can I connect a 5V fan directly here?

Thanks and sorry for my bad English.

Answer:
5 V and 3.3 V are both
logic "highs"
in computing and measured against GND. If the fan simply has to know the on stance and nothing more, then you could run a fan with the logic 5 V (and probably 3.3 V for about 50% spin speed).


Question:
I've done calibration test with "Concentric circle test" (https://www.thingiverse.com/thing:11895) and at specific points there are little bumped points on the print. Also Thingiverse page of the test mentions about these.

How can I solve this problem?

My printer is Creality Ender 3 Pro, I use Esun PLA+ with 210 celcius extruder and 60 celcius bed temperature.

Here is the printed object, both are same print, just took photo on different base.

Answer:
5 V and 3.3 V are both
logic "highs"
in computing and measured against GND. If the fan simply has to know the on stance and nothing more, then you could run a fan with the logic 5 V (and probably 3.3 V for about 50% spin speed).


Question:
How should I describe this part which looks like a small gear so that I can research replacements?

This came with my FLSUN 3D printer, which may be based on a Prusa design.

Answer:
It is an "aluminum timing  pulley"
https://www.google.com/search?psb=1&tbm=shop&q=aluminum%20timing%20pulley&ved=0CAMQr4sDKAFqFwoTCMis1KHmiuMCFRoMswAdMqUElxAB
https://www.ebay.com/i/152446519860?chn=ps&var=453435947176


Question:
I've upgraded my stepper drivers.

I'm looking to understand why my stepper motors made noise in the first place.

Answer:
To make a stepper perform a step, block signals are send to energize the coils to position the rotor. Such a block signal causes abrupt motion and triggers harmonic frequencies. This is audible as stepper noise. If the block signal is smoothed, the motion is more fluent and less noise will be observed. A similar effect is achieved using micro-stepping.
It could be that the new stepper drivers use more/less microsteps
1)
or a smoothed/block
1)
signal opposed to the previous drivers, hence less/more
1)
noise.
1)
The question does not state if the noise is reduced or increased, but noise reduction is most probable


Question:
Developing an electronic product for which I'll need an enclosure. It's about 50x30x20mm and should survive higher temperatures (50-60 degrees). Because of the low volume (under 500 required per year), I'd like to go for an enclosure option that doesn't require a huge upfront cost. So ended up at 3d printing.  As the product will retail for around 500$, the surface finish needs to be up to a higher quality than the standard pla prints that I've seen. From my own research (3d printing noob), the best material for this would be ABS. Maybe with some manual polishing at the end. Then I'd either buy a 3d printer and do it myself or find a company to do it.

What am I missing? :)

Anything I'm missing? Thanks a lot.

Answer:
ABS should be able to handle the the temperatures you describe. ABS will have a similar finish to PLA when it first comes off the printer, but you can refine and smooth your results via an acetone vapor treatment. This only takes a few minutes per piece, and can cost as little as a $1 bottle of fingernail polish remover, a used coffee can, a bit of wire, and some paper towels.
What you're missing is the hobby-level 3D printers ($1000 and below) can be
extremely
finicky. You're not gonna get the kind of quality you need the first print out of the gate. Or the second. Probably not the third or fourth, either. And then you'll find every now and then something isn't quite right any more, and you'll need to troubleshoot why.
You certainly can make this work... just be prepared for what you're getting into.


Question: When I print parts in ABS, acetone vapour smoothing is a good technique to get a smooth finish. Is there an equivalent solvent or process for parts printed in ASA? Ideally I'm looking for something as easy to obtain as acetone, and not so awful a chemical that I wouldn't want to work with it, but I'd still be curious to learn about less friendly solvents.

Answer:
ASA
is Acrylonitrile styrene acrylate. According to Wikipedia:
ASA can be solvent-welded, using e.g. cyclohexane, 1,2-dichloroethane, methylene chloride, or 2-butanone. Such solvents can also join ASA with ABS and SAN. Solutions of ASA in these solvents can also be used as adhesives.
Staff, PDL (1997). Handbook of Plastics Joining: A Practical Guide. Elsevier Science. p. 515.
Solvent-welding means that the material is at least somewhat easily soluble in these fluids (they dissolve the material at the interface and as they evaporate, the former interface layers bond as if molded or welded), and the fact that the material can become an adhesive means that it is somewhat good soluble in these.
The least dangerous (and thus most advised from my side) of these 4 is 2-butanone, the others are listed as carcinogenic, and in the case of 1,2-dichloroethane, also toxic.
If these solvents can be used as a smoother similar to acetone with ABS would need testing, but a short exposition to their vapors should suffice to test this.
Addendum:
These four solvents also are able to solve Acrylonitrile butadiene styrene (
ABS
), which is a quite similar plastic in regards to its contents (butadiene instead of acrylate).
The acrylate rubber differs from the butadiene based rubber by absence of double bonds, which gives the material about ten times the weathering resistance and resistance to ultraviolet radiation of ABS, higher long-term heat resistance, and better chemical resistance.
Wikipedia
Acetone might prove to be also a possible option, but results might differ from those on ABS.


Question:
How can I write G-code for a triangle without sharp tips?

I want to generate the corners manually, rather than using a slicer to generate them, just to know how it is done.

Answer:
Marlin has
```
G2
```
(clockwise arc) and
```
G3
```
(counterclockwise arc) commands that could be used to do this.
You can find detailed documentation for the command here.
Basically, you can use
G2 R1 X5 Y5
to draw a (clockwise) arc from the current position to
$(X,Y)=(5,5)$
with a radius of
$1$
.
So, your rounded triangle could be drawn with 3 straight line moves and 3 arc moves. Figuring out the exact coordinates for each move would be a quite challenging geometry exercise, as you'd need to know where the straight line portion of each side ends and the rounded portion starts.


Question:
Is there a specific name for that problem? What causes this, and is there a way how to solve it?

Printed with PLA, 2 mm nozzle diameter, 0.2 mm layer height, 20-60 mm/s, 200 °C extruder, 60 °C bed.

Answer:
I have experienced this problem.  This picture is one that I could have taken.
It has always been because I was putting too much plastic into the available space.
This has been caused two things: overextrusion -- squirting out too much plastic for the intended layer height, and the bed being too "high" so that the gap between the nozzle and the bed is too thin.
In both cases, too much plastic is trying to be placed in too small a volume.  The plastic has to go somewhere, and ripples follow.  Because the nozzle rubs against the adjacent lines which have already been deposited, an up-bump pushes up the nozzle on the line beside the bump, and a coherent pattern of ripples can form.
The "bump up" is a real effect from the elasticity of the Z-axis, including all the resulting strains of twisting and lifting the nozzle.


Question:
I have started printing about a month ago on an Ender 5 (using mostly PLA but recently also PETG) and it seems it's about time to give the print bed a more thorough cleaning than what I usually do after most prints. I'm using the flexible magnetic mat that came with the printer which has a slightly rough surface, but all of the cleaning suggestions I found so far either did not mention the bed material or were specifically for glass beds.

Can/should I use stuff like acetone or rubbing alcohol on this? Or should I stick to warm soap water?
I have had some fairly decent results with spectacle cleaning tissues but that will only remove grease, not filament residue.

Also, I am occasionally having some first layer adhesion issues (especially with the PETG or when printing things with a circular base) and I was wondering whether common suggestions like glue sticks or hairspray to prepare the bed for printing  can also be applied to the flex mat?

Answer:
I have the WhamBam system which uses a PEX layer over flex steel (which sticks to a magnetic sheet on the printer bed). To clean old material off, I use a "brass sponge" intended for cleaning soldering iron tips to remove the old plastic, then give it a wipe with a paper towel with some isopropyl alchohol (I have 99.99 anhydrous on hand as I use that for cleaning printed circuit boards as well).
The brass sponge is fairly soft, does a good job of grabbing the old plastic without tearing up the PEX layer.


Question:
If a customer sends me a non-commercial 3D model to print, am I allowed to charge money for the 3D printing process? I understand I cannot charge anything for the model nor offer it as a part of my business.

I cannot download the model myself, print and sell it, but if the customer downloads it and sends it to me for me to print it, is it a violation of the license or not?

Answer:
In more practical terms, you could design the part so that the corners are rounded (also known as fillets). This will help keep the print head moving and would prevent the sudden stop and start effect that causes "jerking". Further 8 bit controllers tend to get saturated when reading large amounts of g-code from the sd card or the serial port. Upgrading to a 32 bit controller will prevent that kind of jerking.
Both of these methods pale in comparison to just speeding up the print. Upgrading the hardware to be faster (various methods exist) would yield more of a reduced time than trying to optimize the g-code (in my humble opinion). Delta printers have the potential to be the fastest type of FDM printer, assuming that you could get the filament to melt fast enough.


Question:
Am just wondering if any conclusions can be drawn from this:

Three corners are solid, but not the one in the centre of the plate.

The bed was levelled before printing (and checked afterwards also). Even though the photo may appear to show a slant or lower corner (where the print is coming off), there is not. The bed is level, relative to the extruder, at room temperature.

The temperature of the bed is about 70 °C. I get inconsistent readings (with laser thermometer) but to the finger it feels about the same everywhere.

It's a glass bed, presumably with some coating. Is it degraded? Local temperature variation? Any ideas anyone?

Answer:
From here:
https://io3dprint.com/review-anycubic-i3-mega-ultrabase/
Ultrabase Bed
  The Anycubic i3 Mega Ultrabase is the latest version in the Anycubic i3 family. As hinted in the name, the main upgrade from the previous version is the Ultrabase bed. This is a textured coating on the Borosilicate glass bed that means you don’t need to apply any glue or tape to the bed to make your prints stick to it.
Ultrabase is similar to the popular BuildTak beds except unlike BuildTak it doesn’t wear off and the most significant benefit is that parts are exceptionally easy to remove once the bed has cooled.
The Ultrabase surface has a Moh’s hardness of over 7. This means you can safely use metal scrapers and blades to clean it without risk of it scratching!
Perhaps it was just not cleaned sufficiently from a prior print.


Question: How to successfully pause 3D printing and turn off the printer and the next day, continue to print the model?

Answer:
1) Cut the model up in several parts and print one each day. Remove each part every day and in the end, glue them all together.
2) Cut the model up in several parts and each day, add a G-code to the file to be printed so it lowers the heat-bed and thus starts to print on top of yesterdays print. This cannot be used when the printer is auto-calibrating as the printer-head would crash into the already printed part. It would probably be tricky.
3) Pause the printer in the evening, then resume next day (don't forget to lower temperatures and rise them again tomorrow).


Question: So after a long print the walls in the print begin to weaken and it appears they might not be printed at all.  In the upside down picture you can see the weakness where the two pieces are separated.  I'm wondering if perhaps reducing my speed and changing the extrusion size from .35 to .45 which is larger than the extruder itself.  Thanks for any help and suggestions!

Answer: What you refer to as weak walls in fact are under-extruded walls. This can be caused by multiple sources, but, since the print recovers this most probably is caused by filament that is entangled on the spool (this causes more friction for the extruder and as such less flow, so under-extrusion; like as if the filament is being pulled back). Any other source that may induce extra friction is equally valid. E.g. kink in filament when using a Bowden configuration (long time extra friction in tube) or friction on the spool itself (I once had severe under-extrusion as the spindle of the spool caught a plastic bag which got wrapped around).


Question:
I am trying to slice a model that is half a mm less than max width, but not successful.

What am I missing? Is there some minimum value less than maximum allowed, or something?

Edit: after changing the width to 220 in machine settings, slicing works. This is a dangerous thing to do, as it could damage the printer.

Answer:
Take a look at this post:
https://community.ultimaker.com/topic/15588-cura-23-not-using-full-print-area/
. As the raft/skirt/brim will fall outside of the build volume, Cura is not able to slice it. Look at the the answer by @ahouben. He suggests that if you want to use the maximum build volume :
adhesion type = brim
brim line count = 0
travel avoid distance = 0
horizontal expansion = 0
support horizontal expansion = 0 (if support is enabled)
draft shield disabled
ooze shield disabled
infill wipe distance = 0
Note that in most cases brim with brim line count=0 will get you most of the way there
Try this and see if it makes a difference.