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Ultimaker Cura 3.6 choosing to fill in narrow walls with diagonal striping
I'm playing with printing some Lego-like bricks. I'm using brick models where the wall thicknesses are aligned to match an exact multiple of my printer nozzle (.4 mm nozzle = 1.2 mm brick walls, vs the standard 1.4 mm), with other adjustments to the interior ridges of the brick so they should still fit with real Legos.
I'm seeing an odd effect when slicing in Ultimaker Cura 3.6. My settings for Wall Thickness/Wall Line Count are 1.2 mm/3 lines. And yet, in the layer view, I see one wall line, with diagonal striping between those walls:

Part of it could be the interior ridges creating some thicker walls in places, but if you look at the piece on the left, there are no ridges (it will be a plate, rather than a brick, and Lego plates don't use ridges). Yet it still has the striping. I re-measured the STL in 3 different modelling programs (Meshmixer, 3D Builder, Tinkercad) and all show the walls as exactly 1.2 mm thick.
I then noticed I can remove this by putting something small (even .001 mm is enough) in the "Horizontal Expansion" setting:

This is more what I wanted, and it cuts the print time almost in half. I can also fix this by setting enough bottom or top layers to handle the whole piece with a wall thickness of 1 line...
... but why was it necessary? What is going on here?

Have you tried increasing the number of shells? Why do you want a wall thickness of one line?

a good note: print quality improves a little if you use a little wider extrusion width than the nozzle.

@Mick I want a wall thickness of three lines, like the second image.

Hmm! It's not a problem with Simplify3D, which is what I mainly use. With Cura, the only way that I could do it is by changing the wall line width to 0.3mm. Could you not create a solid brick, and then print with no infill and no bottom layers? Personally, I would would adjust the wall line width to get the required number.

Slic3r seems to do what you want, although I am not familiar with it.

OK. Try setting the infill percentage to 100%. That should do the trick.

The fact that shifting by 0.001 mm changed things suggests a rounding error or sharp threshold between "wall layers" and "infil" selection.  And that it's dependent on the extrusion width setting.   But in the end, will you have trouble if you, say, set the infil to 5%?

If I use the default 0.8mm, 2lines, and do the horiz expansion, I get the desired result.   I also get the desired result with horiz expansion =0 but the source model scaled to 100.1% . But scaling to 100.01% reverts to infil.  So I'm still voting for roundoff error.

All slicers have their own peculiarities, and one of Cura's peccadilloes seems to be that It likes to generate an even number of shells for narrow structures, even if an odd number of shells would work nicely. Slic3r and Simplify3D have no problem with this, and will automatically generate an odd number of shells if they will fit the model.
Cura, on the other hand, will reduce the number of shells and generate infill. If you have set the infill percentage to less than 100%, it will try its best to fulfil that requirement, and in your case, generate zigzag infill. However, if you set the infill to 100%, it will, in effect, create an additional shell, although it is really infill that follows the direction of the walls as far as Cura is concerned, since there is no space to generate the specified infill pattern pattern.

Setting infill to 100% did not change anything.

@JoelCoehoorn That's a pity. It did on the test model that I created (a square pipe with 1.2mm walls). Even reducing the infill to 99% caused it to switch to zigzag infill. Are your sure that your walls are exactly 1.2mm wide?

@JoelCoehoorn Can you proved a link to the STL file so that I can play around with it? This is an interesting little problem.

You can get the stl files here: https://www.thingiverse.com/thing:3424550
I used both the 2x2 brick and the 2x2 plate, with the raw stl files included there (no need to use the thingiverse customizer app yet). Remember, I'm looking to match the second image, not the first.

What if you set the infil to a square pattern, essentially limiting it to one pass along each side of the brick?

I think there's a misunderstanding here. The diagonal striping is not infill, because it completely fills up the space even with infill set to something low.

@JoelCoehoorn You're partly right. Cura shows them as Top/Bottom layers (colour-coded yellow), and the direction can be controlled in the value for Top/Bottom Line Directions. However, if you set the infill to 0%, they disappear. If you set the infill to anything other than 0%, they are included, but they are generated as if they are part of top/bottom layers, not infill. Now I remember why I switched to S3D.

I see what you're saying. I hadn't tried 0% infill, and when I do not only does the striping disappear, but there is nothing inside there at all!


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Replicator+ Motherboard Model
What is the make/model of a MakerBot Replicator+ motherboard?
I'm assuming that the make is now MakerBot since they are now closed-source.

really good question. someone who has it should open his machine...

I don't have a MakerBot Replicator+ to verify with but, if this Geetech wiki post is to be believed, MakerBot printers use their own own open source design called 'MightyBoard'.

@Dr.MantisTobbogan Thanks for the link, but that's for the original Replicator generation that was released around 2011. Since then MakerBot Industries has gone closed-source. The Replicator+ has its controls screwed shut and I'm afraid if I open it there might be some alignment issues, given the history of their frame designs...

It might be this board, MakerBot 5th Generation motherboard, (original image)

The image was very small, so it is rather blurry, I'm afraid.
I have contacted the suppliers for confirmation, and will update this answer, when/if I get a reply.
However, according to this eBay item, Makerbot Replicator Motherboard Carriage, it could be inferred1 that the same motherboard (MP6292) is used in the Fifth Generation and the Replicator+

This part is the aluminum carriage that attaches the main board to the
  printer frame.
Compatible with Makerbot Replicator Fifth Generation (5th Gen) and
  Replicator+ (Plus).
NOTE: Motherboard show here is for illustration purposes only!
  Motherboard (MP6292) is NOT included.
Main board presses right onto the carriage. No special tools are
  needed for assembly. Retaining screw is included.

A much clearer shot of the MP6292 Motherboard

1 However, that depends on whether you want to trust eBay descriptions.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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Ender 4 problem with printer stopping mid print
I'm looking for suggestions to what might be causing my prints to stop mid print.
I slice with Ultimaker Cura 3.6. Some prints work fine and others randomly stop at different heights for no apparent reason; they are not getting stuck, hung up or lifting. Prints just seems to pause. The quality of the prints are great up to the stopping point. This happens with SD cards and octoprint. Using Hatchbox PLA. All stock Ender 4 parts, no upgrades other then magnetic bed attached to a piece of steel. Bed was manually leveled and auto levels with sensor attached to extruder.

Add if it comes to a complete standstill or prints without filament, maybe add a link to the G-code, add a link to a visual recording, insert photos, what does the printer LCD say (make photo) or what else you can think of that helps clarify the problem etc.These intermittent problems are very hard to troubleshoot.

Since you have octoprint check out this answer to set up serial logging, maybe that will help: https://3dprinting.stackexchange.com/a/8047/13883

One more in the continuing series of "Creality Ender isn't working."  Somehow I get the idea that they are not going to be my first (or tenth) -choice vendor.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Slicer software capable of working with large filaments
I'm starting work on a very large 3d printer that uses very large filament. The idea is to house the entire thing in a shipping container and print things as large as cars.
Filament will be some type of epoxy that is to be extruded out of a large 25mm nozzle. A second smaller nozzle using the same material will be used to do finer edges. A third nozzle will be used to produce supports of a different material.
I know this is quite different than most 3d printing applications. I am wondering what slicers I should look into using that are adaptable enough to work with these constraints, or if such software exists.

Size should not matter, what you need to look out for is a slicer that is clever enough to cope with a large nozzle for the rough shape and the fine nozzle for the details. A separate support extruder is no big of a problem. A university we work with have a similar setup as you to produce CF/PEEK moulds, I'll try to find out the software they use, but it is most probably custom software.

Interesting question.

Now I'm curious. You are using epoxy? What is the minimum cure time of that epoxy? Are you heating the environment inside the container?

I can't reveal a lot about it due to confidentiality concerns. Hopefully I'll be able to show it off when it's done.

I don't think I'm heating the inside environment though.

After checking it up, Ultimaker Cura (and possibly most other slicers capable of multi-extruder setups) is able to handle multiple extruders of varying nozzle size and seems to be ok with 25 mm Nozzles or something ludicrous such as 200 mm filament. You should aid its slicing in some way:

Dedicate one nozzle to the support structure, that's easy.
Design your parts with 2 shells:

One is the main body with corners cut to the main nozzle's extrusion diameter.
The other is the corners and details.

Would I treat the 2 shells as different parts for the sake of printing properly?

@henradrie You would need to assign each shell to one of the extruders.


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Small filament globules/bubbles in print using Ultimaker 3 extended
Lately, I've been having a problem with the surface of my prints. As shown in following picture:

Printing material is PLA. I've changed the print core (this is the terminology, Ultimaker uses for their hot end for e.g. Ultimaker 3 and 5; these cores come in different nozzle sizes and for different materials) but even with a different print core it happens from time to time (although less frequently). To me it seems like the extruded stops printing for a while and then continues. I've not been able to catch it while it happens though.
Any thoughts?

What's the print temperature and bed temperature?

@Trish Bed temperature: 60 degrees Celcius, print temperature: 200 degrees Celcius

My first two guesses: 1)clogging of the nozzle. What diameter opening are you using?   2) leaking somewhere in the hotend leading to droplets; this is less likely given the bad/missing layers that align with the blobs shown in the picture

@CarlWitthoft I think you might be spot on with the clogging idea. Seems like no filament is extruding until a sudden burst of material is released? Nozzle size is 0.4 mm

Have you printed a lot? Ultimaker advises to clean the extruder (it can contain shavings of filament grinding, don't open the extruder housings if you're not handy, they contain some parts that jump out when you open it and need to be at the correct place on assembly again), clean the tubes and clean the cores. Core cleaning is pretty simple, heat up the hotend an disconnect the Bowden tube on top of the print head and use some higher temp material like nylon to push/pull the filament out of the core.

Where you ever able to solve this issue? I have the same problem with Ultimaker 3 Extended.
I'm using 0.4mm nozzle, PLA, 60 degrees bed and 205/2010 degrees print


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Is it safe to use a 3D printed icing smoother?
I want to 3d print my own icing smoothers, but I'm not sure if its safe to have plastic from a 3D printer in contact with cake icing. Is there any harm in this?

As a rule of thumb, FDM 3D printers are generally not Food Safe.
https://3dprinting.stackexchange.com/questions/147/which-are-the-food-safe-materials-and-how-do-i-recognize-them
https://3dprinting.stackexchange.com/search?q=Food+Safe

While PLA filament doesn't really pose any issues since it's basically corn (or other from other plants) starch ... why would you want to print something anyway? You can purchase icing smoothers which are mass produced for far cheaper than you could design and print something through your printer.

yes, that would be safe, generally. The plastic itself is not harmful. Certain dyes or additives might not be hypoallergenic.  The big problem though is storing and cleaning; the micro-fissures in 3d prints can harbor pathogens. Don't use the same tool over and over for days without washing. Better yet, replace after each occasion and you'll likely be fine. IANAL.

These are all great ideas for food safe use of 3d prints. I was just looking into whether I could produce some ice molds but this saved me some grief, I think I'll contact smooth-on to see if they have a solution to this dilemma as to the micro crevices that bacteria can adhere to and grow in. I think there might be a way to coat the places the print will be in contact with consumables, "e.g. the inside of the molds where Jello or ice might be prepared, or even repeat use cookie cutters." That would solve these issues, especially since smooth on sells food grade silicone resin that can be used

Only certain plastics are safe enough to be used to contain or manipulate food. ABS and PET-G are such materials. The 3d printing process however is not food safe because, it creates crevices in the printed part into which bacteria and other contaminants can cling to. A printed part would need to be coated in a silicone rubber to render the surface both inert (can't grow anything) and smooth (no crevices). Further, the type of plastic you use must be able to be sterilized in boiling water. PLA softens in boiling water. PET-G variants can as well (think clear plastic bottles). This is why most food handing utensils are either glass or stainless steel.
If you are going to use a 3d printing process to produce parts that are to be used for food, you also have to consider containment from the machine itself. The brass nozzle, the teflon tube, the extruder gears etc. The filament itself may not have come from the factory as clean as it would need to be to be used around food.
If you are able to coat the heat resistant part in silicone and you only use it a few times (ensuring that it is properly washed and sterile) then it can be used for food prep purposes.
There is a difference between food grade and safe for contact with food.

Acrylonitrile/butadiene/styrene copolymer identified in this section may be safely used as an article or component of articles intended for use with all foods, except those containing alcohol, under conditions of use E, F, and G described in table 2 of 176.170(c) of this chapter.

Abstract from: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=177.1020

Can you provide any references about ABS being food-safe? I’ve always thought the exact opposite... but I’m no expert on the subject :-)

Very good short version! A little "do you want to know more" I have to add though ;) And on the alcohol: many prepared foods contain small amounts of alcohol for some reason or another even if unlisted.

Note that the mention of tiny crevices only applies if the utensil will be kept and used repeatedly (not specified in OP), and that this applies to any material, not exclusively to ABS.

As mentioned, FDM 3D printed parts are flawed for food service and prep use regardless of the material, because of the small gaps between lines where bacteria can grow, and because your printer isn't used in a way to keep it from introducing contaminants into otherwise clean material.
However, there are some ways around this.
Single-use
I'm pretty comfortable using my printer to make items for one time use. If I wanted an icing smoother with a fancy shape for a special cake that I'm not likely to need again soon, I'd go ahead and do that. I would apply all the icing at one time, and then I'd discard the piece, rather than try to clean and save it. Also note that I'm not talking about a commercial kitchen; this would be for a cake I'd eat myself with friends, rather than sell.
The big thing I've done this way so far (I've had my printer less than a year) is make shaped cookie cutters. I'll print the cutters, use them, and then throw them away. If I want the same shape again some time, I'll re-print.
Lining
The other thing you can do with food prep items is print them with the intent to use liners. For example, here is a 3D-printable taco train, where a train car has grooves to hold  tacos (yum!). It wouldn't be good to put a taco directly in here, but you could use napkins or similar food-safe liner to separate the 3D part from the food. In the case of the icing smoother, you might be able to print the part and wrap it in aluminum foil.


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Anet A6-L won't turn on again
I've just assembled my new Anet a6-L (with auto leveling). At first everything goes well, it turned on ready to setup but a couple hours later the printer just shutdown and won't turn on for about an hour. I carefully followed the steps concerning the wiring part (below are some pictures).

I just don't get it.. The power supply does light up the green LED when connected to power. Could you guys help me?

Welcome to the stack, but sadly without further info we can't help. What did you do before it stopped and shut down? Does the LED light up or not?

It is strange that the printer fails and cannot be switched on, usually this hints to overheating of electronic parts. Have you checked for excessive heat of the electronics?

Have you checked the output of the power supply? Just because the lights are on doesn't mean it's putting out any juice. A multimeter will help you figure this out.


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Extruder Motor Not working during Printing
I am a newbie trying to setup and configure a 3D printer following online YouTube videos and tutorials. I am trying to configure a Hypercube Evolution 3D printer.
I followed Tech2C videos (on YouTube) and was able to configure Marlin firmware to some extent. I am using Pronterface to send test codes and taking files from thingiverse.com for testing.
Configuration :

CoreXY
Board : Ramps 1.4
Extruder Setup Type : Direct drive using Titan e3D
All end stops, temperature sensors, heaters configured and verified.

What is working :

X,Y,Z axis movement directly from panel.
Homing is ok.
Temperature sensors, heating bed and hot end as expected.
Extruder motor working with direct on panel command.

What is not working :

When I send a print file (taken from thingiverse.com), the X,Y,Z axis work but there is no extrusion what so ever. I have tried a lot of things but using files from thingiverse, the extrusion of filament is not there whatsoever. It's been 2 months trying to figure out whether the issue is in firmware or the file, however to no use.

Can anyone help me get out of this or point out where I can be going wrong?

Hi Mandeesh welcome to 3D Printing.SE! I've built a HyperCube Evolution, maybe you could share your configuration.h file (a link to it please) so we can have a look for you!

What slicer are you using to convert the STL files into g-code? Most printers cannot handle STL files directly. Also, is Pronterface communicating with the printer? Can you home the head from Pronterface, for example?

Check that the printer is not in debug (dry-run) mode.

Did you unzip the file, then slice the .stl into a .gcode?

Thanks for the response.

@0scar Link to configuration.h file (https://1drv.ms/f/s!AmYgCJyTo4vUjib-2QzINY1czbpe)

@Mick Yeah I guess I took g codes direcly from online websites without slicing as per my printer. Now I am using Slic3r for the same. I have attached the sample file above which I am trying to print. Yes homing is working fine.

@Trish Yeah I figured this our quite late actually and this may be the problem.

Never use someone else's g-code (except for manufacturer's test files supplied with the printer). Always create your own. Treat every printer as if it is unique, because it is.

I'm voting to close this question as special unclear because it seems to be abandoned and some rather vial questions (like the slicer) have not been addressed. As such it is impossible to answer thoroughly.

If the extruder extrudes fine from the control panel, chances are there's a configuration problem somewhere. For example, check your extruder steps/mm in the firmware to make sure it's not a nonsensical value; check the slicer settings to make sure that the filament diameter, line width, and layer height are all correct; make sure you're not trying to extrude in volumetric mode without having configured volumetric printing in your firmware and slicer correctly; and finally check your temperature control settings. When I first set up my fleabay 3d printer, I couldn't get my printer to work because the hotend minimum shutoff temp (thermistor disconnect protection basically) was set to something like 195C and the print temperature was 180C. I had an almost identical issue when I changed my fan assembly and it started blowing on the wrong part of the hotend, causing the firmware to register that entirely too much energy was being put into the extruder. Check the minimum temps for both hotend and heated bed and see if one of them is tripping your failsafes and stopping the extruder before printing even begins.

wth the process described, OP might have forgotten to slice the object too... though then it should not work at all...

authors: ปล่อย มือฉัน


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How neodymium magnet affect (if any) on extruder motor
I saw on a popular site simple indicators for attaching to the axle of an extruder motor (Prusa printers). Those gadgets are spinning due to movement of motor, both clockwise (pulling filament) or counterclockwise (retracting). But all of those things are attached to motor axis by small neodymium magnet (round, 8x3 mm). I searched informations how such magnets affects for stepper motors and I read that magnet field can significantly change magnetic field of the motor. On presented movies for gadgets which I saw, the motor seems to have no trouble with rotating but AFAIK neodymium magnets have really strong magnetic field and I am curious how its centric orientation due to motor axis:

inhibits rotation
if yes, how much it raises the temperature of motor?
how it affects for electronic of filament sensor?

Currently I use Prusa i3 MK3 printer and during long (~10h) printings an extruder motor is enough hot and I don't want make it hotter. I want to print and attach such "rotation indicator" but the fact of used magnets made me started to thinking about magnetic field of motor. Or maybe those changes are so marginal to think about them?

How strong of a magnet are you using? Only a small magnet would be necessary to attach it on I guess.

Also, how sciency you want your answer to be?

I've updated my question for sizes of magnet which is suggested to use (round, 8x3 mm). I want simple answer, like: "You can use it safely, in this case it's not to be worry about" or "it's not a good idea, because influence of the field will be too strong and will cause...". Thank you.

The best way to know is placing the magnet on the shaft; if you see that motor starts shaking or stops this mean that you affects the motor operation, but I think if any magnet interference can be deprecated due internal coils of the motor during operation.
The motor works with some coils in the rotor and some magnets in the stator (motor frame). But the shaft is to far from the coils to be affected for the magnetism of one small neodimiun magnet which needs at least 7mm to trap another small metal objet or for induction sensing and 2mm as maximum for creating electrical flows (generation); this values are afected if the magnet is placed over other metal part reducing his atraction field, and the armor is too big for an small magnet 8x3mm.
You can attach some indicator with a double sided adhesive tape (3M) if still are worried about affecting your extruder.
If your motor extruder is heating during extended usage periods you should adjust the motor current, for example: you motors is rated 0.5A you should calibarte the current for 0.48A or 0.45; this could reduce the torque force of the motor by a little. Or maybe the current current :D is calibrated above 0.5A thats way you are getting over heating.

I don't see where your heating is referencing to

Thank you. The answer is enough for me. I'll check the gadget with magnet. I'll hope it won't raise the temp of motor significantly but when it will I'll search how to calibrate the current.

No, this feature won't raise the temperature.


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Slic3r - how to combine specific perl code with Slic3r SupportMaterial.pm?
I've got a specific perl support tree script that I would like to integrate into Slic3r. Does anyone know how to do that?

Welcome to 3dPrinting.SE!

I'm voting to close this question as off-topic because it appears to be more about programming than it is about 3D printing. Modifying a slicer's code is well outside the scope of this stack, I'm afraid.


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Ender 3 severe under-extrusion
I've been using my Ender 3 for about four months now and it's been working wonderfully. The print quality is amazing and all the prints are very strong. Then about three weeks ago, my entire system crashed while Ultimaker Cura was open and it lost the profile for my 3D printer. I recreated the profile to the best of my ability with other people's working profiles online, but none of them worked right. I've been getting severe under extrusion in all my prints, and they're incredibly fragile. For now, I've just been printing a 1"x1"x1" test cube. I've tried many steps from other people's posts online to fix the problem, including:

Raising the print temperature for PLA to 200 °C.
Checking the extruder for signs of too little tension or too much tension. I checked, and the PLA has light tooth imprints on it, and no grinding or damage to the filament.
Clearing out the extruder. I disassembled the whole extruder assemble, and flushed all the plastic from each part with a heat gun, and metal pick, and then tried reprinting, but it didn't work.
Trying a newer Ultimaker Cura version. At the time, I was using Ultimaker Cura 3.1 and hadn't updated because it was working well. I then tried the newest stable release of Ultimaker Cura 3.6, with a few different profiles, and then I also tried the beta version of Ultimaker Cura 4.0, but none of these worked.
Increasing the extrusion rate. I incrementally increased the extrusion rate from 100 % all the way up to 130 %. The prints looked a little better and were a lot stronger, but this still didn't fix it.
Trying a different slicer. I then downloaded Slic3r and created a new profile in that. The prints turned out a lot better, but there was still significant under extruding.
Checking the filament tube for any burns or damage, and ensuring it's inside the extruder assembly all the way.

If anyone can help me figure out what's going on with my printer, I'd really appreciate it!
Here are some pictures of the prints I've been getting:
These were made in Ultimaker Cura with different small changes to the profile made

These were made in slic3r with a flow rate adjusted up to 130%

These were prints I made before I lost all my settings in Ultimaker Cura.

Here's some of the material I read/watched and checked before posting myself:

I am experiencing some severe under extrusion
Sudden underextrusion on Ender3
r/3DPrinting: Under extrusion on Ender 3
Fixing a Filament Flow Problem on CR-10 mini, CR-10 or Ender 3 by CHEP

Edit: Here's my printer profile:
Ender 3 Profile Google Drive

Hi Tinkerman255 and welcome to the 3D Printing.SE! I don't want to rude, but your "good prints" are not that well either. Are you sure it isn't an issue that progressed over time or over the crash? Please do check the filament diameter setting, it fooled me countless times when I changed to a newer Ultimaker Cura version and use both 2.85 mm as 1.75 mm filament intermittently.

I agree with you that the print quality before the crash wasn't the greatest. However, it was very consistent and strong, so I had no complaints. It printed with that quality since the time I got it, so I'm confident it isn't an issue with the hardware. As for the filament diameter, I made sure it's all set correctly, and that hasn't helped either

It is not too rare to create a new machine in Ultimaker Cura to be set to 2.85 mm as this is the default. Also some bugs in the past did reset or assume this diameter unless you manually set it, and unless we know your exact version we can't confirm it is really this.
Underextrusion why?
The 0.55 mm more radius result in an underextrusion due to the pressed through volume, and since $V=A\times l$, we need to see the area to see how severe the underextrusion is for one given extruded length. $A_{1.75}=2.405\text{ mm²}$ and $A_{2.85}=6.379\text{ mm²}$ are rather obvious, so $\frac {\text{real extrusion diameter}} {\text{calculated extrusion diameter}}=\frac{A_{1.75}}{A_{2.85}}=37.7\ \%$, so only about 40 % of the needed filament is pressed through the nozzle as the slicer thinks it is almost twice the diameter. This matches well with the 130% still being very spotty, as that'd need a much higher factor to compensate for the underextrusion. A compensating extrusion multiplier would be $\frac 1 {0.377}=265.25\ \%$.
Fixing
To fix this, check under filament and set it to 1.75 mm so you force the correct diameter. Remember that filament diameter is not saved in the printer profile but in the material database.
You might need to restart Ultimaker Cura to activate these new settings.

Agreed. It's a classic Cura gotcha.

I created a new printer profile and made sure the filament diameter was set to 1.75". I then made sure the material was set to PLA 1.75". I'm still getting severe under extrusion. Here's my current settings: https://drive.google.com/file/d/10_HiEnVGtU1GS1N-Scy-6KG363BIa31d/view?usp=sharing

None of the settings in this file, or the one on the question, have anything to do with filament diameter.

Also, by my math converting both 1.75 and 2.85 diameters into areas of circular filament cross-sections, 1.75 is less then half the area of 2.85. You'd need 204% extrusion to make up for the incorrect setting.

Finally, there was a bug in Cura where it would ignore your filament setting if you did not have a specific material selected, and revert the default 2.85. I believe this was fixed, but not knowing what version of Cura you have, make sure you actually select a material, and the filament size is set for that material.

@JoelCoehoorn corrected, I messed a factor 2 somewhere...

Okay, I figured out what the problem was and it is twofold: In Cura 4.0 changes to your filament selection don't seem to take effect until you restart Cura. After I did this, the filament diameter was correct and that helped a lot with the print. Secondly, I noticed the lever that controls the feeder pressure was wiggling, and so I tightened that bolt. Those two things combined lead to the atrocious prints I was getting. Now everything is working perfectly!

@Trish BTW, the problem was that you should've divided the area of the 2.85" diameter filament by the area of the 1.75" diameter filament. This would've given you the correct extrusion flow rate of 264.7%. Instead, you have the numerator and denominator flipped.

@Tinkerman255 Beware that it isn't inch ("), but the diameter is in millimeters [mm]. But you loose the unit once you divide the two. (One inch is 25.4 mm)

@Tinkerman255 please do not post files from external websites. If you must, please include the key portions in the question, as the question will not be able to stand the test of time when the file link is removed.

My Man, The Ender 3 Marlin firmware saves your E-Steps on the SD Card and you basically have to check the E-Steps every startup because the Firmware sets back the E-Steps Value every shutdown to the minimum 93. Thats a known issue of the Enders and still on the Mk.3 aka Ender 3v2 present. It's an easy fix.

SMarlin? Would that happen to be a typographical mistake?

The following saved me from under extrusion on Ender 3 Pro.

Check the diameter of the material referenced and the nozzle parameter in your slicer (Cura, ...). Then re-slice.
If not sufficient, it may be a printer parameter issue. The extruder parameter is missconfigured: the stepper to filameter distance ratio is not correct and as a result, it does not feed the  requested length of filament.
To fix the printer parameter, send the following gcode sequence (use a G-code console like "GCode Sender - Pronterface").
We will follow this procedure:

ask to feed 100 mm of filament
mesure the actual length feeded
read the parameter inside the printer
write correct value.

G-code:
M83 ; set to extruder relative mode
; Be ready to mesure how much filament will really be consumed
G1 E100 F100 ; request 100 mm of filament
; Let "L" be the length in mm you mesured
; Now read the extruder related value in the printer
M503 ; and let "V" be the last number at line "echo: M92"
; Then set the correct value
M92 E{V*100/L}; Eg "M92 E222"
M500 ; write to memory

It turned out to be the tensioning spring on the extruder drive that was the issue. It provided too much tension at first so loosening the screw that acts as the pivot for the extruder bearing arm solved that. However I found that filament then began to slip inside the extruder so adding a couple of spacers to the end of the spring fixed that. Now it's extruding great.


text:
Inconsistent quality on different sides of the print - Ender 3
Fairly new Creality Ender 3.  Seems like everything is leveled and snug, belts tightened.  However, some of the sides are coming out stringy.  See the image of this simple dome - you can see some of the areas on the right are pretty nice, but other side is stringy.  Similar story on XYZ cube - e.g. X comes out pretty well, but its opposite side is stringy and separated.  Any ideas?  Thanks.

This looks like over extrusion, have you calibrated the extruder steps per mm?

Welcome to 3dPrinting.SE! While you state the belts are tight, did you ensure all of the rollers move freely? If you are getting bad results on the Y-axis, I'd ensure the bearing rollers under the bed are moving freely. You don't give a print orientation (a picture of the calibration cube would be good here) of which direction is which in the above image, so have to figure from what you state in the question as to the rough side being associated with the Y-axis.

Which side of the print was the cooling fan on?

Thanks everyone for the suggestions/questions.  Answers in order.  PerplexedDipole, yes, verified that 100mm uses precisely that much filament.   Paulster2, rough sides are only the opposites of Y and X, which is find very puzzling.  Checked the rollers again, they seem fine.  user77232, the cooling fan is the standard position, which is the right side of the extruder.  I had a suspicious about the fan, but turning it off makes no difference!  Bottom line, still baffled :-/


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Controlling a 3D printer with another Arduino device over serial
If this is a silly question I apologize but I am trying to establish a serial connection between a 3D printer (Ender 3) and an Arduino Nano over the USB port.
I am able to connect the 3D printer to a serial monitor on my PC and send G-code to it and control the printer. I am also able to connect my Arduino to the serial monitor and also send and receive strings.
When I connect the Arduino directly to the 3D printer using a USB cable and separately powering the Arduino the 3D printer does not seem to respond to the G-code being sent over serial.
What am I missing?

Welcome to 3dPrinting.SE! Are you sure your communications settings are correct going from the Arduino to the printer? You might want to double check to make sure.

I'm not sure if I understand this correctly: You want to print by sending all commands via computer->ardunio->3dprinter? If yes: Bad idea, because if the computer gets a problem (e.g. a little hickup, auto turn off, and so many more) the print will fail. And have a hickup while a eg. 10h print is way too easy.

Do you try to do Something Like Octoprint?

This isn't really a 3D-printing issue as much as it is about Arduino, USB, and how serial connections over USB differ from a generic UART serial connection.
For a UART-based serial connection, there are only two devices, and both devices are peers - either can send data to the other with no real restrictions as long as the speeds are set correctly.
USB allows multiple devices to be connected, and is much more complicated. One device must be a "host", which manages everything. The other devices can be much simpler as they don't need to be a host. Typically, your PC is the host, and your keyboard, mouse, memory stick, Arduino, printer, etc. are all just attached devices.
If you've managed to connect your Arduino's USB port to your printer's USB port, the problem is most likely that neither device has hardware or software to be a host, so the USB connection won't work.
There was a "USB Host Shield" for Arduino, but is is no longer in production. Perhaps you can still find one somewhere, or somebody else makes an equivalent.
There is also an Arduino "USBHost" library, which is compatible with the Arduino Due only.


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Anet A6 stock power wires.. the live, the zero and the ground. Which is which
As an electrician newbie I have a question..
Short question
My power plug is attached to the wall outlet and three wires are at the end of it.. the blue, the brown and the green/yellow oen.
How to determine which is the live, zero and ground wire WITHOUT depending on the colouring?
I want to know this to always be able to check the wiring, if I don't trust it.
Also, I have these sub questions that follow from my situation:

Why does the test screwdriver lit up when connected to the apparant zero line?
How can I determine the live/zero line using a multimeter

Situation
My tools:

a test screw driver
a multimeter
the ANET A6 manual

In the manual it states that

brown is the live wire
blue is the zero wire
green/yellow is the ground wire

I know that in some countries this colour coding is the standard and can be trusted. I just want to be able to check it.
So, my first hypothesis would be.. if I put the test screw driver on the live (brown) wire, lay my thumb on the end, the internal bulb would glow.
This did not happen.
It did happen when I put it on the zero (blue) wire. So I am a bit confused by this.
My second trick was using the multimeter. Using the positive and negative probes to determine the polarity and therefore decide how the current was flowing.
But there was no sign of polarity... duh.. because I was of course on AC, which is always Alternating.. hence no sign information from a multimeter.
So, how CAN I use a multimeter to determine the live/zero line? Maybe measure the current from live/zero to ground? Is that a safe option?
PS: my first post on this forum.. so please correct me where needed

Wouldn't this be best asked at the EE.SE?

@0scar I thought, since this has to do with the Anet A6 wiring that this could be a nice place for it. But you do have a good point, shall I move it to there?

Don't worry about moving, the community decides! :)

@0scar - This question would be dead on arrival over on EE.SE.

As it is alternating current, why are you interested to know which is which? (I'm referring to the blue and the brown wire, the green/yellow has an obvious purpose)
E.g. a CEE 7/4 plug can be flipped around in the CEE 7/3 socket. When you flip the plug (180°), the brown and the blue switch places, it is all depending on how the electrician in your home attached the brown and blue wires in the socket and depends on the socket and plug you use.
The only benefit would be that when you cut the power with a relay, you may want to have the power on the side of the relay, not the printer; but again, that does not matter when you flip the plug 180°. Note that some plugs inhibit rotation, so it also depends on the plug and socket you use and where you are located.

oh god.. of course.. I never realized that when you turn it 180° the lines switch... then a follow up noob question.. how does my power supply for my Anet A6 deal with this possibility for switching internally? And why is there a standard on the 'live' and the 'zero' line then..?

@zwep remember it is alternating (AC), so it does not matter. The rectifier diodes in the PSU will create a DC from this AC. No matter how you attach it. Hook it up and have fun with printing!

Thanks, yeah I understand that :) I just read some introductory things about rectifier diodes and how they translate the AC to DC. This definitely helped in my understanding of my PSU!

It matters a lot .  The return line (blue) is intended to be at or near ground.  The brown line is hot, and is the source of current.  If your wall plug is wired wrong, that's a dangerous situation.  Next, nearly every power supply i'm aware of expects "hot" on the marked post. If you cross the wires, the internal electronics will most likely fry due to potential differences between Return and Ground(neutral).   BTW,  the AC voltage sine wave is on the Brown wire, oscillating about the (hopefully) 0V return wire.  The AC current is out of phase with the voltage most of the time.

@CarlWitthoft It depends on where you live, you are probably accustomed to UK plugs, in Germany and The Netherlands you can flip the plugs, so it does not matter. I believe French and Italian sockets have a pin, so plugs cannot be flipped.

This picture shows the correct wiring for a British 13A mains plug:

The green/yellow wire must always be connected to the earth terminal (at the top of the plug). This is most important, and will prevent electrocution if something goes wrong.
The brown (live) wire should be connected to the fuse, and the blue wire to the remaining terminal. It is true that, since alternating current is being used, the device will likely work if the blue and brown wires are swapped, but it is better to stick with standard practices to avoid confusion.
I would not use a "test" screwdriver to determine which terminal is "live" in this instance, simply because it is unnecessary. The live terminal is always the one that the fuse is connected to. This is done for safety reasons since the device is automatically disconnected from the live side of the circuit if the fuse blows.
How to wire mains plugs is really beyond the scope of this stack. Watch appropriate YouTube videos if you want to make a competent job of it. The only advice that I will give is to always use a proper fuse of the correct rating for the device. Never use something like a paper-clip. Also, don't use the 13 Amp fuse that comes with the plug. The fuse is there to protect the cable, rather than the device. Most printers will draw less than 5 Amps, and will be supplied with a 5 Amp cable, so use a 5 Amp fuse.
Also, never work on a plug while it is connected to the power socket. This is most foolhardy, even if the socket appears to be switched off.


text:
Prusa I3 mk3 - Not your average inconsistent first layer
Over the last two days I have tried everything I could come up with to fix the following issues.
It all started with bad bed adhesion.(pic.1) Solutions for these problems are readily available, so I calibrated my Z-axis (did the whole wizard from start to finish again) and started a calibration print over the whole buildplate, getting an interesting result.(pic.2) As you can see some area's are squashed nicely whilst others come off directly.
I then started looking for alternative Z-levelling solutions and came across an alternative calibration file (link1), at first glance the results seemed allright, -0,8mm seem to provide the best results (pic.3) however notice the darkened area to the left (could be the high temp of this test? 225c?).
To validate the number I did a full print on -0,8 and this is where it gets weird, the result shows a non uniform transparancy (pic.4) the mechanical properties are also a lot less. I used my caliper to check the printer and all seems to be well within expected ranges.
The bed is also flat, checked with a ruler for deformaties.
Printing with the first spool of Prusa fillament, do notice some changes in the Z-level calibration print, the edges now bend upwards, this is done with the same Gcode and spool as previous (pic.5).
Any advice on what to do next?
Printing on 210c with fan off for the first layer, test square on 225c, all PLA.
Cleaned the bed with Acetone (99% pure) before each attempt.
Picture 1:

Picture 2:

Picture 3:

Picture 4:

Picture 5:

EDIT: So Mick mentioned cleaning the nozzle which helped with the inconsistent first layer. In the end it was me being unaware that Aceton doesn't help with grease, a thorough scrubbing of the buildplate with soap and really hot water helped.

have you cleaned your PEI sheet with some alcohol recently? Fingerprints ruin the adhesion, alcohols or acetone remove them nicely.

Hi Trish!
My problem seemed to have been two-folded, first being (as Mick below mentioned) a partially clogged extruder. The second part was grease.
I believe that my adhesion problem started by fingerprints but worsened after I tried the glue stick. Cleaning the bed with Acetone did not help. Cause, and I did not know this, acetone apparently is quite ineffective on the wax-like layer created by the glue stick. So a scrubbing with boiling hot water and some dishwasher soap did wonders :)
Thanks you!

If you repeat a test and the problem occurs in the same location, then you probably have a problem with your bed or build plate. However, picture 3 suggests to me that you may have a partially clogged nozzle. Manually extrude some filament. It should fall straight down. If it curls as it comes out of the nozzle, then you have a partial clog. Brass nozzles do wear out, so if you've put some hours on your printer, it might be a good idea to fit a new one.
Edit: I meant picture 3, not picture 4.

Hi Mick, I cleaned the nozzle after reading your comments.
The result of the square is a lot better!
What helped more was to clean the buildplate. I used Aceton and was unaware that it doesn't help to get the grease of the plate, after a thorough scrub the PLA is sticking like never before.
Thank you for your comment!

The Prusa i3 is coated with a PEI sheet. PEI and other build plates stick to the build but don't like to be dirty. Fingerprints can build up and create an interference layer of fats that lessen the adhesion to a point the pieces spontaneously pop off.
A good cleaning is often needed. For PEI Isopropylic Alcohol is a fast cleaner, but if you can remove the build plate soap and water work too - but take care not to go too hot as PEI can get damaged. For BuildTak and similar, Acetone also can do the job.
When using Gluestick to create a deliberate destroyable adhesion layer (for filaments fusing with PEI that can result in chipping out chunks) clean the surface afterward with a little water. In the choice of gluestick, make sure you get a PVA based one.

Thank you Trish, as mentioned above the gluestick was part of the problem. Biggest issue was that I thought aceton would be a miracle solutions against the greasy buildplate. Assuming it was all clean I kept trying to print on gluestick residue. The stick itself came with the Prusa I3MK3 so am assuming it is the suitable kind ;)
Will refrain from using it again with PLA, cleaning from time to time should be enough.


text:
Any video tutorial for 3D printing
I am new here and would like to work on a project to 3D print a precision prototype. What is the most affordable way to do it? How do I go about it?

[The question ask asked is vague, but since you are new it is understandable.]
If you want to build a precision prototype then you have to decide on the level of precision that is necessary. There are different types of 3D printers and services available which give various levels of precision and functionality.
Fused Filament Fabrication/Fused Deposition Modeling - This is typically a means of producing functional prototypes using plastic filament. In terms of precision it is currently the lest precise, but the most cost effective.
Binder Jetting - This is basically crazy glue with food coloring which is inkjet printed onto a white powder layer by layer (vast oversimplification). Useful for producing prototypes with colours for product mockups but not for functional parts. This is mid the mid point in terms of price and precision.
Stereo Lithography / Photo polymerization  - Lasers cause a liquid resin to harden and stick to each other. Also notable for being the first form of 3D printing, this is the highest precision that is easily attainable. The cost varies based on the provider but it is usually the most expensive option.
Depending on your needs you may find that it is cheaper to develop a single prototype part (just one part not an entire machine) by sending out to a contract manufacturer as opposed to purchasing a 3D printer.
Here are some examples of what to do when:

If you want to develop a diamond engagement ring for a customer: Send out to a contract manufacturer, for Stereo Lithography
If you broke part of the cupboard and its easy to design a new one: Consider purchasing a sub $400 USD FFF machine and learn to use it.
If you are developing a new line of designer sneaker: Send out to a contract manufacturer for Binder Jetting.
If you are doing miniature figurines for a stop motion animation television series: Invest in a Binder Jet machine and learn how to use it.

In my experience, people don't buy a 3D printer until they have held a 3D printed part in their hand or have seen the machinery in person. If you are new, start with a contract manufacturer and when you start spending so much on them that it is equaling the cost of owning a machine, then invest in your own system.

These two videos seem to give a good, general, entry-level introduction to the various technologies and processes that are involved in 3D printing:

The Ultimate Beginner's Guide to 3D Printing - Part 1
The Ultimate Beginner's Guide to 3D Printing - Part 2


text:
What does a stand alone "T" index value do?
I'm using IdeaMaker for slicing my print objects. IdeaMaker start strings have a >T0< standing alone on one line and then >T1< on the next line. What does this accomplish?

Welcome to 3dPrinting.SE!

Could you post a snippet of the "start strings" (is that start G-code script?) so everyone knows what you mean? E.g. is it commented out or not, please let us see.

T stands for "Tool" and has its origin in the origins of .gcode being for other automated machine controls. Depending on the machine, everything could be a tool for .gcode, like an actuator or pump or a spindle motor or a drill.
In 3D printers, the T-controlled tool is usually the extruder motor. Convention has it that the indexing always starts at 0, so T0 and T1 are your first and second Extruder respectively. It is the way to choose which tool is used.
As a side note: E is not originally intended for extruders but for the feed rate of lathes.

I'm not sure what it's doing in your case, but the "T" code is there to select the extruder number. T0 would be the first and T1 would be the second extruder in a multi-extruder setup. I found the information at the end of this cheat sheet.


text:
Anet A8 Wrong Hotend Temp
My Anet A8 reads as 120ish degrees Celsius, but it is set to 200 degrees. I don't know if it is reading the wrong temperature because it still pushes out plastic when I force it. It will climb up and then go back down. I don't know if the hot end it broke or if the thermistor is broke.

Welcome to 3dPrinting.SE! Are you using what the system says the temp is, or are you using an infrared thermometer to get the temps?

You are sitting on a fire risk!
If you are using the stock/original firmware, you should immediately stop printing. The stock firmware of the Anet A8 has no thermal runaway protection (see also this answer), this means it will keep heating until the thermistor senses 200 °C, even if it cannot do that for some reason or another.
When a hotend temperature does not read the correct value, your thermistor in the hotend may not be making correct contact (as you say that it goes up and down). Please ensure that the thermistor is correctly positioned, it makes good contact and the wires correctly fastened.
Similarly applies to the heater cartridge, which can fall out and causing a fire if not properly fastened. Ensure the heater cartridge is properly positioned and held in the heater block.
Fluctuations in temperature sometimes are induced by a wrongly positioned fan duct (but generally not that much). The reason why this is not the case here is that you can still push the filament through while it reads about 120 °C; this temperature is generally too low to push filament through. Apparently the hotend is still hot enough to push filament through while registering a low temperature.

Without any other information, the highest odds are that the fan is blowing on the hot end.    If the temp drops when the fan is on, and rises when the fan is off, then simply re-position the fan nozzle.    If that's not the problem, check the thermistor.   If that's not it, check the termination (tighten the screws) of the hot-end wires at the control board.
Next, check the control board.   If there's any indication that it's the board, one potential solution is to add a MOSFET (see the link).     Even if the control board isn't the problem, I would add the MOSFET.

There is no need for external MOSFET modules unless the OP has the first version board. Either way, a MOSFET for the extruder is not needed, the current is not that high and the MOSFET components on the Anet boards are decent. It was the connectors of the first board version that started all the problems. And the connector of the heated bed not being rated for about 9 Amperes.


text:
What is Thermal Runaway Protection?
What is Thermal Runaway Protection (TRP) and why should I enable it?
How does one do so in Marlin?

What is TRP and how does it work?
Thermal runaway protection is basically self-explaining; it is protection against the temperature getting out of control. Essentially, the firmware checks whether the measured output of the thermistor (What is a thermistor? A thermistor is basically a temperature sensor; it is an electrical component (more specific: a resistor) that has a large reduction of its resistance when heated; it is frequently used for measurement and control as you can link the resistance to the temperature via a table or a curve) is within an expected range for a certain target value within a certain time frame when heating the hotend or the heated bed.
E.g. When you request the hotend or heated bed to a certain temperature, the heater elements are being scheduled/switched on to increase the temperature. If the temperature increase as a result of scheduling the hotend or heated bed are not met in time (settings in the firmware configuration), the printer will halt and heating of the heater elements will stop. The printer needs to be reset after such a failure.
What triggers TRP?
Common problems that trigger the thermal runaway protection are:

a faulty thermistor,
an incorrectly placed thermistor (e.g. not making good enough contact with the heater block),

including falling out

a loose heater cartridge,

including falling out

faulty connectors,
faulty or partially broken wires,
basically, anything that interrupts either heating or the measurement of the signal.

Why should TRP be active?
Thermal runaway protection is mainly meant to prevent fire hazards by stopping the heater cartridge when it might have fallen out of the heater block and is trying to set the whole surroundings on fire.
To illustrate the point: This happens if Thermal Runaway Protection is disabled, and the associated story. Luckily this one did not result in a loss of life and home, but it could have - and the owner was able to do some forensic examination on what caused the fire.

How to activate TRP in Marlin firmware?
Please make sure that you have the configuration lines in the Thermal Runaway Protection section (466-485) of your Configuration.h file uncommented (no // in front of the lines starting with #define THERMAL_...).

//===========================================================================
//======================== Thermal Runaway Protection =======================
//===========================================================================

/**
 * Thermal Protection provides additional protection to your printer from damage
 * and fire. Marlin always includes safe min and max temperature ranges which
 * protect against a broken or disconnected thermistor wire.
 *
 * The issue: If a thermistor falls out, it will report the much lower
 * temperature of the air in the room, and the the firmware will keep
 * the heater on.
 *
 * If you get "Thermal Runaway" or "Heating failed" errors the
 * details can be tuned in Configuration_adv.h
 */

#define THERMAL_PROTECTION_HOTENDS // Enable thermal protection for all extruders
#define THERMAL_PROTECTION_BED     // Enable thermal protection for the heated bed

Note that Marlin 2.x has an additional protection for the heating chamber:

#define THERMAL_PROTECTION_CHAMBER // Enable thermal protection for the heated chamber

This should generally be enough to enable TRP on your printer, fine tuning can be done by changing the time constant and the temperature increase in the file Configuration_adv.h in the section:

//===========================================================================
//=============================Thermal Settings  ============================
//===========================================================================

However, it is advised to not change these values unless you are absolutely certain; e.g. if your heating cartridge is not powerful enough and you are getting printer halts. When getting false-positive printer halts according to the Marlin firmware you could:
* If you get false positives for "Thermal Runaway", increase
* THERMAL_PROTECTION_HYSTERESIS and/or THERMAL_PROTECTION_PERIOD
How to test if TRP is active on my printer?
To test if thermal runaway protection is enabled on your printer, you can disconnect the heater element of the hotend or the heated bed while printing a print or sending temperature commands to the printer over USB using a terminal to send commands directly to the printer. You can disconnect the heater element while the printer is cold (before start) and also when the heater element is heating up. No heating of the nozzle will take place, so after the period defined by the time constant set in the firmware, the printer will halt if thermal runaway protection is enabled. Power down the machine and reconnect the wires, it is not advised to put them back in on a running machine, as one might touch the open wires; when the printer halted, you should power down or reset the printer anyways. If the printer did not halt, power it down as quickly as possible - TRP is disabled.
Further Considerations
Besides activating thermal runaway protection, it is always a good idea to install a smoke detector and a fire extinguisher in the surroundings of the 3D printer: the smoke detector over it, the extinguisher within arms reach of the door leading to the room.

What is Thermal Runaway?
Let's look at a Thermal Runaway Test (#2) performed by one Chris Bate.
In this video the experimenter drove the heating element non-stop until disaster. The Nichrome wire in the heating element melts at about 1,400 °C. Only once it melts, will the circuit will break and the current stop. The aluminum heating block however, melts at 660.3 °C; long before the nichrome melts.
Thermal Runaway Protection
Thermal runaway protection is a piece of code in the firmware of the printer that checks to make sure that once power is being applied to the heater, the thermistor's resistance is changing within a specified frame (time and amount). This is the basic form of a control loop.
If the control system is implemented mechanically then it is called a thermostat, usually via a bimetal strip.

A good basic primer. You might enhance the answer a little by providing how TRP can be activated - iirc it is just flipping the correct bit.


text:
Are there printers that don't have thermal runaway protection?
This question asks about the reasoning behind thermal runaway protection and how to turn it on. However, how do I know if my printer does not have protection in the first place? Either because it is shut off by default or, if such printers exist, is not a feature of the printer.
For example, the Creality CR-10S, a popular family of printers, has TRP not enabled (or deactivated) for some reason. Since there are a handful of printers (Creality, Tevo, Anet, Prusa, Ultimaker, etc) that seem pretty ubiquitous in the community and are recommended for beginners, it seems like it'd be handy to know whether or not any given printer has this safety feature.

technically, the nomenclature should be "not enabled" in this case, as "disabled" would mean it was deliberately turned off and it was(is?) not enabled in the default marlin distribution for a long time.

I got the impression it was deliberate because why would one turn off a safety feature all willy-nilly like? The reasoning may not be evident, or sound even, but I imagined there was some sort of reasoning.

yes, but they did not turn it off, they just grabbed the default marlin distribution (where the community deemed the feature experimental and thus disabled by default) and did not enable it.

Ah that makes sens now. Thanks for clearing that up as well.

At the time of this writing (March 2019), many (if not most) cheap printers from the Far East are not delivered with Thermal Runaway Protection enabled as Marlin had this feature disabled as default for a long time (it was for certain so in April of 2018).
I know that Anet printers (A8 from experience) and the Creality Ender-3 printer (experience from another member) come with TRP disabled in the firmware when shipped from the factory. Thomas Sanladerer did a test on his machines and found that it was disabled on the Creality CR-10, Anet E-10 and A-8 had it disabled while the Mini Fabrikator v1 did have no Mintemp/Maxtemp but Thermal Runaway. Even the quite expensive BCN3D Sigma R17 had it disabled in April of 2018 on default.
Among the printers that come with Thermal Runaway Protection enabled are the PrusaResearch builds of the Original Prusa i3.
To test if it is enabled on your printer, you could disconnect the heater elements prior or during printing, see this answer or the process explained in Thomas Sanladerer's Video above or from the start of his safety tutorial:

How to test if TRP is active on my printer?
To test if thermal runaway protection is enabled on your printer, you
can disconnect the heater element of the hotend or the heated bed. You
can disconnect the heater element while the printer is cold (before
start) and also when the heater element is heating up. No heating of
the nozzle will take place, so after the period defined by the time
constant set in the firmware, the printer will halt if thermal runaway
protection is enabled. Power down the machine and reconnect the wires,
it is not advised to put them back in; when the printer halted, you
should power down or reset the printer anyways. If the printer did not
halt, power it down as quickly as possible.

While my question was intentionally general, now for peace of mind I ask specifically about Creality. I read that the CR-10S is deactivated and has to be enabled in the firmware, which I've done. So when you say Creality Ender printer is not equipped with TRP... do you mean that it's just shut off in firmware, or the printer cannot use TRP?

@LuxClaridge Trish has an Ender 3, I don't know the details of that printer.

@LuxClaridge I added also Thomas Sanladerer's video that showed live on camera him testing the 'parent' of the Ender3 (CR-10) and the firmware is pretty much identical. It had been disabled by default in default marlin distributions in April 2018.

@Trish Thanks! That coincides with what I remember reading (which was a hot minute ago).


text:
Spraying aluminium hydroxide nanoparticles onto PLA as fire retardant?
Several scientific papers study FR-PLA (fire resistant PLA) in which Aluminium Hydroxide nanoparticles are melt blended into the PLA (example source: Advances in Flame Retardant Poly(Lactic Acid). Would spraying the nanoparticles (dispersed in a liquid -source - maybe non flammable silicon oil) onto a 3D printed PLA help with fire resistance or not make a difference?

Why would spraying water help? It's not going to infuse the particles into the plastic. At best it would make an extremely thin useless layer.

We could disperse the particles in another liquid than water: https://www.us-nano.com/inc/sdetail/1094 Which liquid would stick onto PLA? Silicon oil maybe?

It has to be inside the pla. This is more a question for a material science Q&A site.

@user77232 i have transferred the question to the physics Stack Exchange as well: https://physics.stackexchange.com/questions/466676/spraying-aluminium-hydroxide-nanoparticles-onto-pla-as-fire-retardant

That... is Material sciene and chemistry, not physics and not here...

BTW,  "Fire Retardant" is not "FireProof" .  See the expose articles on cigarette smoking, fire-retardant furniture and bedding.  So long as there's an exposed heat source, fire-retardant material will continue to burn.  So the whole concept re PLA is pretty much pointless.


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Printing temperatures for ABS on a Flashforge Adventurer 3
I've recently acquired a Flashforge Adventurer 3 and am having difficulty printing with ABS. The initial layers seem to lay and stay pretty well, though after a few more moments, one side will peel up from the heated platform. I'd like to know if anyone has optimal and tested temperatures for the use of ABS on my printer for the nozzle and platform?
I've used FlashPrint for slicing my objects using the following options:

Supports: Disable,
Raft: enable,
Resolution: Standard,
Layer Heights: 0.18 mm,
First Layer Height: 0.27 mm,
Perimeter Shells: 2,
Top Solid Layers: 4,
Bottom Solid Layers: 3,
Fill Density: 15 %, Hexagon, Every 2 Layers,
Print Speed: 60 mm/s,
Travel Speed: 80 mm/s,
Extruder: 225 °C,
Platform: 70 °C,
Cooling Fan Controls: Automatic,
Nozzle Dia.: 0.4 mm

The most commonly used print temperature range for ABS is 220 to 240 °C with the major bulk around 230 °C. Some filaments are blended with inhibitors or PC, increasing their print temperature to up to 260 °C. Note that the color of the filament just as the brand can have an impact on the print temperature!
The most commonly used bed temperature for ABS start at least at 80 °C. MatterHackers suggest 85-90 °C.
If your bed is particularly bad at getting adhesion, you might want to clean the bed of residues and fingerprints and relevel the bed. If that is not enough and you use a glass bed, a slurry of ABS in Acetone could come in handy. If you have a glass bed, the slurry is pretty much the best option.
Print cooling is a bane on ABS - the stuff shrinks too fast if cooled, resulting in the parts breaking loose!

Thanks so much. I am trying your suggestions now. Fingers crossed.

@BlackManta2020 I corrected myself a little - and also linked to matterHAckers, who know their stuff really well.

If one edge is peeling up, the first layer isn't sticking.  You may need to go through a first-layer troubleshooting process.

Is the bed flat and parallel to the Z-plane traced by the printhead?
Are you taking appropriate steps to attach the ABS to the bed?
Is the bed hot enough to reduce shrinkage of the printed ABS object?

For sticking ABS to the bed, I've had good luck with two approaches:  a PEI-coated bed surface, or ABS slurry on a non-PEI surface.
For bed temperature, I usually run a little hotter: 100 °C.

A little hotter than... "usual" or "other machines"? up to 10 °C difference between two machines are easily accumulated from differences in the temperature sensor placement and calibration as well as the presence of an enclosure or not.

Note that some of the other advice is general advice which is not applicable to the Adventurer 3.
Temperature control is somewhat limited on Adventurer 3. The maximum bed temperature is 100 °C. There is no "glass bed".  My Adventurer 3 is struggling to get the bed temperature to 98 °C.  (The room temperature is 16 °C at the moment).  I'm using Blu Stik glue on the bed to hold the print. Another possible problem is loss of heat out the side when the filament reel cover is off.  The cover of mine is off because the reel of ABS does not fit in the bay.  I've seen designs for filament bay covers with a hole in them to feed the filament in on Thingiverse.  I'm considering building a box to put the printer in to keep the ambient temperature high.

Having the same issues with the Adventurer 3. I have printed the TUSH (The Ultimate Spool Holder) and cut a 3 cm hole in the door. This enables me to run the spool directly into the printer with the door closed unsing a minimum sized hole.
I am also printing the pieces at 235 °C nozzle temperature using glue as a heatbed adhesive.
The adventure 3 has no build plate adjustment apart for adjusting the nozzle height when it is centered. Does not leave you much room for adjustment.

I bet you meant 235 ºC instead of 135 ºC! :) Thanks for your shared experience to print ABS on the Adventurer and your solution to keep the door closed while the filament is outside the printer chamber.

This I hope will help:

You must see which is the type of ABS you use, in terms of temperature. If you have an ABS material which melts at 220 - 250 °C it is difficult cu work with it using an Adventurer 3. For example I use Verbatim (220 - 240 deg Celsius) and that works well.
Bed temperature must be set between 90 - 100 degree Celsius.
For beginning, it is good to work with Raft activated.
Do not use "Cooling Fan Controls: Automatic", because the fan will work all the time. This is not good, it will peal your raft all the time because of the temperature difference between bed and fan blow. It is good to set the cooling fan "ON(when to pre-set height)" usually I use 1 mm to 1.5 mm max. This will start the cooling fan at the height you indicate.
Always use the cooling fan as mentioned before because your print will be much better with it, you'll see.

I often read that you should not use the cooling fan at all with ABS


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Firmware upload
I have a 3d printer without a firmware. It's a Wanhao Duplicator I3.
I try to upload a version, but I have a little problem, at uploading on melzi board, it's a V03 version.
I try this tutorial : https://www.youtube.com/watch?v=ejpSniiJejI

You have to be careful when compiling Repetier-Firmware, since successful compilation is dependent of using the correct version of Arduino Studio. What version of Repetier-Firmware are you trying to compile?

In any case, you have a compilation problem, not an upload problem. That will come later.

You are not bound to use Repetier firmware, you can also use Marlin firmware, I've read that more than 3/4 of all printers use Marlin, this has a larger fan base and as such more people to help you out. Note you have a segmentation fault as a result of your code changes, these are pretty hard to debug anyways, so starting fresh might be a good idea.


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Error:Printer halted. kill() called!
When printing cube.gcode using Pronterface I get:
Print started at: 23:07:31

After 8 seconds I get:
Error:Printer halted. kill() called!
Error:Printer halted. kill() called!

What is the reason?
How can I see logs?
Additional information:
I connected only three motors, and set the following in Configuration.h of Marlin Firmware:
#define TEMP_SENSOR_0 999
...
#define TEMP_SENSOR_BED 999
...
#define X_MIN_ENDSTOP_INVERTING true // set to true to invert the logic of the endstop.
...

(Also for min max for XYZ)
In 8 second X motor and Z motor were running.
This is the link to G-Code print file (cube.gcode).
I'm using Marlin 1.1.x on a Arduino Mega 2560 + RAMPS 1.4 without endstops.

Hi, welcome to 3D Printing.SE! The question is a little terse to answer, please add what exactly happens in the 8 seconds? Does the printhead home to the limit switches? Does it try to heat up the nozzle?

To find the reason, we need more info. E.g. o you have end stops? And do you home the axes in the G-code. Adding a link to the G-code file could be helpful!

Could you please help me understand "I connected only three motors."  An FDM 3D printer usually has at least 4 motors, three to cover the 3 x-y-z degrees of freedom, and the extruder.

I did it only for test purposes.

Your G-code file contains the G28 command to home the printer, as you do not have endstops, execution of this command fails. If you do not use endstops, you should never home the printer, instead you must position the print head at the origin yourself (generally this would be at coordinate [x=0, y=0, z="paper thickness"]) and remove homing commands from your G-code file.

It helped. But I detect new problem. https://3dprinting.stackexchange.com/questions/8482/after-some-time-stepper-motor-is-hot


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After some time stepper motor is hot
I have three stepper motors.
One Nema 17 - 2.4 ohm, the second smaller noname from color printer - 9.5 ohm and third the smallest noname from cdrom - 10.5 ohm.
I have connected them to arduino mega 2560 with ramps 1.4(set to 1/32 micro stepping) and drivers drv8825. See my previous question.
After some time (less than one minute) the first is cold. The second motor is hot. And the third is very hot. I can not even touch it.
What can I do to fix it.

there should be labels what they are rated for on the smaller motors.

see also: https://electronics.stackexchange.com/questions/164426/what-stepper-motor-is-in-a-cdrom-drive

Add fans to the motors.

Note that you should unlock your steppers when not in use. When an "idle" stepper gets hot, it's using energy to keep rigidly locked at a precise rotation (often for no good reason).

@Davo, they work constantly.

The second motor is hot. And the third is very hot. I can not even touch it.

This is to some degree, completely normal and expected. From the datasheet for a typical NEMA 17 stepper, the rated temperature rise is 80 °C above ambient and the maximum operating temperature is 130 °C (implying an ambient temperature of 50 °C). It is normal that stepper motors (in general) get a bit hot.
"Too hot to touch" is still relatively cold. 60 °C is already too hot to touch, and that's only a 40 °C rise above a 20 °C ambient temperature.
You can reduce the temperature rise of the motors by reducing the current they receive. The stepper driver has a small potentiometer that can be turned to adjust the current, but keep in mind that doing so will also reduce the torque of the motors and thus they might skip steps if you reduce the current too much.
Technical details: Note that stepper motor drivers used in 3D printers are constant current drivers, and the little potentiometer controls the current. If you had not paid much attention to this potentiometer, the drivers might all have been set for the same constant current of $1.0\ \text A$. The stepper driver would (to achieve the same constant current) send a higher voltage to the higher resistance motors. This would imply a power dissipation of $2.4\ \text W$ in the Nema 17, and a power dissipation of $10.5\ \text W$ in the small stepper. $2.4\ \text W$ in the Nema 17 would only heat it up by about $20\ °\text C$ above ambient. A dissipation of $10\ \text W$ in the small stepper, which also has much less surface area to dissipate the power, would heat it up by a lot (and probably, given that you didn't fry it, the current was set lower -- or a technical peculiarity limited the current given that the motor likely also has very low inductance).

2 of his motors are not NEMA 17 but salvaged from other machines.

Stepper motors, in general, may be rated to operate at higher temperatures. "Too hot to touch" could still be completely normal. I am just using that datasheet (for a NEMA17) as one example of how hot steppers can normally get.

true. note though that a typical CD-drive Stepper with 5V/10 Ohm is like 20 (or 24) steps per turn...

I have reduced current by reduced voltage from 0.65 V to 0.15(cold)-0.2(warm) V for cd motor and 0.2(cold)-0.4(warm) V for color printer motor.

@burtsevyg can you measure the current instead? but reducing the current to about a third means that about that is for the current too, which means about 1/9th of the power dissipated.

@Trish A reference voltage of 0.65V translates to a current of 1.2A, so the current has been reduced to around 300-500mA for the small motor and 500-700mA for the large one.

@Trish I will try. Should I measure the current on single сoil?

Unless you have changed the factory stepper driver settings, they will all be set to deliver the same CURRENT to the motors.  Stepper drivers operate as constant current supplies, so the voltage supply does not determine the power sent to the motor.
The power dissipation in a circuit is the current squared times the resistance.  $P = I^2 R$. Because the current is constant, the 10.5-ohm motor will dissipate over four (4) times the power of the 2.4-ohm motor and will get much hotter more quickly.

Problem statement
Your RAMPs board is supplying your drivers all with similar voltages, with the basic settings calculated for a NEMA 17.
So, we got different Resistances R, so why do they heat differently?
Physics background: energy transformation and dissipation
Resistance can be described as "friction of electrons in the conductor" to some degree. When electrons flow through a wire, then a current $I$ is trying to equalize a potential difference $U$. A flowing current transforms the kinetic energy of the electrons ($\propto U$) into an electromagnetic field and heat from the resistance. The electromagnetic field then is used to spin a rotor together with the magnets in the motor, which transforms the energy in the field into kinetic energy again. The end result is, that the kinetic energy of the electrons is transformed into the motion of the motor and heat.
Can we get the Current?
OR: "What if there was no driver?"
How does Resistance figure into all this? Well, Ohms Law is there: $U=RI$. With it, one can solve how much current I flows through an aperture of known resistance R and voltage U. The operation of the circuits that contain a CD stepper motor is usually 5 V, while 12 V is used for NEMA 17 and the typical steppers from Printer/scanner combos.
Those results wouldn't match the currents they are operated on as the motors are supplied via a motor driver chipset. We can look up the spec sheets to get a short glimpse of how they might dissipate heat in both constant voltage and constant current setups. Most stepper driver adjusts the voltage so we get constant current but there might be some cases one wants constant voltage. To estimate their heat generation, one needs...
Joules Formula of electric Heating
Constant Voltage case
Joules Formula of electric heating is written as $H=I^2Rt$, which gives us Energy in Joules. We can make it easier on us and drop the time to get the derivate power of electric heating. $P=\frac{H}{t}= I^2\ R= U \ I=\frac {U^2} {R}$

$P={12\ \text V}\times {0.4\ \text A}=4.8\ \text {W}$
$P=\frac{144\ \text V^2}{9.5\ \Omega}=15.14\ \text {W}$
$P=\frac{25\ \text V^2}{10\ \Omega}=2.5\ \text {W}$

if we throw 12 V at the poor small stepper though...

$P=\frac{144\ \text V^2}{10\ \Omega}=14.4\ \text {W}$

How did the small one survive this torture? I have no idea!
Constant Current case
Now, that is pretty much "constant voltage" but the stepper drivers used try to give always a set constant current to the motors. For most motors I have found, this is apparently in the area around 0.5 A, which gives us a better estimation

$P={0.25\ \text A^2}\times {2.4\ \Omega}=0.6\ \text {W}$
$P={0.25\ \text A^2}\times {9.5\ \Omega}=2.375\ \text {W}$
$P={0.25\ \text A^2}\times {10.5\ \Omega}=2.625\ \text {W}$

If they all are operated at the same, set current (with adjusted voltage to match that), we get about a factor 4 for the heat generation on the middle and 4.3 on the CD stepper. Even with a higher current, the factors for heat dissipation are what is really interesting here.
Heating and temperature
Another small part of the answer is the mass of the motor and when it was touched. The thermal energy $E_T$ in a whole object is not directly equal to the temperature $T$ of the object, it is just proportional to it but also the specific heat capacity $c$ of the body... all in all we get for an amount of energy $Q$ deposited in an object $\text Q = \text m\ \text c\ \Delta\text T$.
Assuming that c is equal for the motors, one can do a quick estimation with typical weights via $\Delta\text T \propto \frac H m$
A typical NEMA 17 motor weighs about 280 grams while the typical CD-drive stepper (PL15S-020-PNA9) weighs 19 grams.
You see, the smaller steppers not only dissipates more heat, it also heats up faster than the chunky NEMA 17. The reason why after a short time the smaller one with not that much more heating than the big one felt considerably hotter is, that there is less mass that needs to be heated up: it might be already at its maximum temperature while the middle one still is heating up.
All in all
This is not a marlin issue but one from your material choice. Getting all similar motors makes motion control all the much easier, but you are not necessarily in danger of burning the motors.
To cool the motors...

figure out what current I the smaller motors want to be operated on and adjust your setup to that, so to stay safe.

there are potentiometers for this on most boards.

mount a heatsink on the motors, increasing their effective thermal mass and their ability to dissipate the heat to the room around by increasing the surface area.

Let us continue this discussion in chat.


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How to remove firmware warning
I'm operating my Prusa i3 MK3 through Octoprint. Basically, this means I can start prints from remote. However, there's the firmware version warning which requires me to press the knob and confirm that message.
I now found a line of G-Code in Printer Settings / Custom G-code which is probably doing this:
M115 U3.6.0 ; tell printer latest fw version

I'm not very familiar with G-Code yet, so before I remove that line, I wanted to know whether that's all I need to do or if there's something else to consider.

Removing that line will not affect your printer, except that it will get rid of the warning displayed on the screen.

I wanted to know [...] if there's something else to consider.

You should probably upgrade your firmware to the latest version to benefit from a couple of bugfixes and performance increases.

I had a couple issues with the last firmware upgrade. Therefore I want to keep this version as long as the printer works fine for me.

@ThomasWeller Maybe these issues can be solved with Ask Question? ;)

@0scar: unfortunately that's unlikely for my case. I first used the Prusa forum. Then I had two phone calls over several hours with Prusa support without any result. I then returned the printer in warranty. They sent me a printer back which looked like a complete rebuild.


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Auto bed leveling: systematic slope
I have a heavily modified DiscoEasy 200 from Dagoma, see picture:

The heatbed is mounted on 4 springs, on top of the original plate. I made sure the X carriage was parallel to the table. I then tried to level the bed manually, with the 4 springs: I pushed the nozzle into each corner of the bed, and used the paper-gauge method to adjust the springs so that the bed would always be at the same distance of the nozzle. I then setup the Z-offset on the machine and tried to print a mainstream bed leveling test from thingiverse. I use a 4 points auto bed leveling.
And I have a systematic problem. Every time I try the bed leveling test, it seems the right side of the bed is lower than the left one. The front and rear right corners seem to be lower than on the left side. I tried to expand the springs of the front and rear right corners, but the auto bed leveling at the beginning of my prints re-introduces the problem.
The right side seems to be ~100 µm lower than what it should be. It's not a lot, but it's enough for prints to fail.
I can't figure out what the problem is. Do you have any idea? it's driving me crazy to not understand where the problem comes from.

Did you check if your bed is parallel to the gantry?
It can happen that after leveling one side and moving  to the other the adjustment there puts the first side out of alignment - I level my bed by doing some couple turns

Did you check if your bed is parallel to the gantry?
Not to the gantry no, but the bed is parallel to the table (more or less, checked it with a caliper, but quickly). How do I check relatively to the gantry? I also do a couple of turns. Also, if I disable auto leveling, the leveling seems all right everywhere.

@JPFrancoia the hotend is a known length. if you level the bed, you actually try to make it parallel to the gantry. You should just repeat the process some times for left-right-front-back again and again, so the error gets reduced with each itteration

@JPFrancoia Though nice, leveling the bed with respect to the table is completely unnecessary unless the X axis is parallel to the table. The bed should be parallel to the X axis movement.

As I understand your question:

You manually go through a leveling process and have it set up well.
You allow the printer to "auto-level".
You print, and the right side is too low by about 0.1mm.

Is it possible that the filament (which is on the left side) pulls up on the extruder when the extruder is on the right side?  A small tug could lift the extruder making it appear the same as if the bed were too low.
If this seems possible, check for the extruder being vertically loose or wobbly.  I've had filament pull forces cause slight head offsets on a home-brew printer.


text:
OpenSCAD "not valid 2-manifold" useful information
OpenSCAD suggests that "object may not be a valid 2-manifold" but it looks perfectly fine in OpenSCAD and in Meshlab.
Have looked through the file several times, and cannot find any point or line intersections, they all overlap in 3D.
Is there some useful software for diagnosing this? It seems to me it ought to be trivial to for example highlight the offending volumes, rather than just print a general error message with no details whatsoever.
Edit: slicing it in Cura works fine also.

Occasionally, a model created in OpenSCAD will have, as you suggest, overlapping segments. Often enough, this will generate the message you receive. OpenSCAD has an implied union function when it comes to independent objects, but if you wish to clear those errors, experiment with explicit union statements where you have joining objects. It may be necessary to join only one pair at a time to clear the error.


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How to fix bulging first layers of print?
The bottom 1-6 layers of my prints always bulge, like an enlarged elephant foot effect. I've tried all the fixes for elephants foot to no avail. I'm using:
XYZPrinting DaVinci Jr 1.0 Pro with their own brand filament (1.75 mm), nozzle: 0.4 mm, tried various layer heights 0.1-0.3 mm, with temperatures 190-205 °C. It has a non-heated bed, using tape as an adhesive.
Problem can be seen here:

Have you tried to add an additional z gap in the slicer or use a slightly thicker paper to level the nozzle to the bed? Your first layer may be too close to the bed.

Since the effect extends past layer 1,2, I'm wondering if this is over extrusion, rather than Z-compression. Nice clear photo.

That's an elephant foot. What are your temperature settings for hotend and bed?

i see that if it's windy in the room with the printer. try a partial enclosure.

Does the effect disappear when print cooling fan speed is reduced or the fan turned off? Does the effect change if the number of bottom shells is reduced?

Was this ever resolved? I'm getting exactly the same results as the OP (i.e. all bottom layers of my prints are compressed causing elephants foot)

You specify that 1 to 6 layers are expanded.
Does that match with the number of bottom perimeters you ask for?  If so, then I would suspect over-extrusion.
If not, it could be a combination of two problems:

The head is too close to the bed, and
The head has too much vertical compliance or springiness.

In this scenario, the head being too close puts additional upward pressure on the head.  The springiness allows the head to displace upward, but it is still too close.  Being too close, the extruded bead is spread out too far.  With each additional layer, the head is relatively less close, and the effect reduces until eventually the head is not displaced by the extruded bead, and the object prints normally.

Are you implying in the second problem description that the gantry e.g. rests on those springy z-screw couplers resulting in this effect? This printer does not have such a coupler.

I am only suggesting that vertical compliance from any source (such as loose linear bearings) could be a cause of the elephant's foot lasting for 1 to 6 layers.

I don't really buy argument #2. In my experience the plastic has trouble exiting the nozzle if the nozzle is too low. There simply isn't enough pressure in the nozzle for the exiting plastic to be able to lift the extruder.

@nathan-headlay The problem is only the point 1 (adjust Z offset), some times the Z height is not enough tall to allow the PLA flows correct , then affects the second and the third layer or even the fourth if the layers height is too small. I got that when I move the printer and skew the Z tower by error, then I need to adjust the Z axis to 90° again.

@0scar The second point is correct also, this spring comes from bed springs and a kind of loosening of the X rods, if you move that part with your hands you will have movement on Y axis like spring which is enough to hide or compress at leat 2 layers. This compression disappears when the Z goes up until friction is nulled.


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How to increase the amount of probing points for a BLTouch sensor in Marlin firmware?
I have a new BLTouch that is setup (using Marlin 1.8.7) but I want to increase the probing grid from a 3x3 to something like a 5x5. I am using bilinear leveling with a 3x3 grid.
How would I go about changing that?

You need to change the constant value(s) in your Configuration.h file of your Marlin version from:

// Set the number of grid points per dimension.
  #define GRID_MAX_POINTS_X 3
  #define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

to:

// Set the number of grid points per dimension.
  #define GRID_MAX_POINTS_X 5
  #define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

This shows that to go from a 3x3 grid to a 5x5 grid you only need to change one value. Do note that you can set GRID_MAX_POINTS_Y to any value other than GRID_MAX_POINTS_X; replacing GRID_MAX_POINTS_X in the line with GRID_MAX_POINTS_Y to 4 would yield a 5x4 probe grid:

// Set the number of grid points per dimension.
  #define GRID_MAX_POINTS_X 5
  #define GRID_MAX_POINTS_Y 4

"You need to change the constant value(s) in your Configuration.h file of your Marlin version" And, how does one do that?

@WeldonThomson Download the firmware, get or configure it for your printer, compile the software and install this onto the printer controller board.


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Printer fails to print a cube
I'm trying to print a calibration cube from PLA using a 70 °C heated build platform on a Prusa i3 Pro W. This results in:

Please explain why it prints like this.

Hi. Please post what type of filament, what bed and head temps, print speed, and any other information that will help folks to diagnose your issue.

There are multiple issues that cause this result.
First, your nozzle is to far from the bed. This can be seen by the curly deposited filament on the build plate (I guess that is the brim or the skirt). Please properly level the bed and position the nozzle at a distance of a plain A4 paper as best as possible (should be doable as you have a glass sheet that are usually very flat as a result of the production process to make glass).
The second problem you face is layer shift. You see that the squares are printed further and further to the left, the print head does not return to original position. Layer shift is usually caused by improper belt tension or a loose grub screw of the belt pulley. This answer describes layer shifting in more detail. This question may be helpful too, the answer contains some references to layer shifting.

I think its the second thing, because its start printing well but in, like 30 sec It hora yo the left, when i hey home (friday) i'll try It and tell YouTube, Thanksgiving for The response!

If I could I'd give your comment +10 for the amazing "autocorrect" your device forced upon you :-)

@ZgestaltZ that autocorrect made my day! Friday is G28 time!

The layer shift can also be caused by the stepper motor "skipping" when it hits an obstruction.  The obstruction can be a loop or ridge of filament sticking up higher than it should be.
As Oscar suggests, the first step is always to make the first-layer-thickness be right.  This is often called "bed leveling", but really it is making sure that the bed defines the z=0 plane that the firmware is expecting.  If it isn't planar, if it isn't constant Z (ie., it tilts in any direction), or it isn't at zero, problems follow.
It seems to have mostly shifted in X, so start with that motor and belt.  Have you adjusted the tension correctly?  Is the motor current set correctly?
Other things can also cause trouble, such as:

A poorly mounted extruder that favors one direction
Bad slicer parameters that command movement faster than the printer's ability
Bad configuration parameters which call for acceleration or velocities beyond the printer's ability.

Are the slicer settings matched to the printer?  If this is a commercial printer, are you using a profile from the manufacturer?  If this is your design, or heavily modded, have you tried de-tuning the slicer parameters and/or the configuration parameters?
Any debugging proceeds from the first step, so adjust the Z=0 plane and see if you can print a uniform, single layer print covering the while bed.  When that is good, you are most of the way to victory.


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Can I schedule prints to start at a specified time?
I want to know if it is possible to schedule a 3D Print to start at a specified time so that I don't have to press start.

My 3D Printer has an Arduino mega based RAMPS 1.4 control board & is connected to a Raspberry Pi 3B running OctoPi 0.15.1

There are a few options to delay starting using either the OctoPrint environment or directly use G-code for this.
The use of G-code is probably the most simple for you to implement. The G4 command defines a "dwell" or pausing period for the next command to start:

Depending on the firmware you use, you can use the P or S parameter to specify the pausing period.
To pause the print job (for 1 hour) you need to insert the following line as the first line of your G-code print file:
G4 P3600000 // One hour pausing; defined in milliseconds

or (if your firmware supports)
G4 S3600 // One hour pausing; defined in seconds

Other solutions may include the adaption of the OctoPrint controls menu structure or use of the REST API of OctoPrint. These options are more difficult to implement.


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Why does the print speed change at specific height? (Using Ultimaker Cura slicer)
I'm trying to figure out why the print speed changes at one point in this model.
I'm using Ultimaker Cura 3.6 and, as shown in the picture, I set the speed to be the same across the entire print. Is there a setting I'm missing?

0scar is right. Changing the minimum time per layer to 1s (from 3s), makes the entire print print at the same speed, as per settings. However, it's probably a bad idea:

Not being able to see the rest of the model (from the first image), if looks as if the light green sliced area displaying a lower speed for the top of the cylinder, is the only part that need to be printed to that height (now confirmed in the second image). This speed reduction is done by the slicer and is not specifically caused by Ultimaker Cura (other slicers do result in similar behavior). Note this is a good thing! Lets explain.
Filament needs an amount of time to cool before the next layer is deposited onto the previous layer. When the layers get small (surface area) and there are no other layers the print head shifts to, the print process is slowed down to allow the filament to cool down; hence you see a decrease in print speed.  If you deposit too fast, the last part of your print will become too hot and will deform.
A print parameter that influences the behavior is the Minimal Layer Time parameter in Ultimaker Cura, please read the hint information of this parameter:

Yup! Just tried and that's the cause. Thanks again!