New user , calibrating the machine & 1st prints - Small problems and doubts?
 
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Dibujor
(@dibujor)
Eminent Member
New user , calibrating the machine & 1st prints - Small problems and doubts?

Hello there. I'm a new Mk3 owner and new to 3D printing in general.

I bought a kit so I could mount the machine myself and understand better how iot works. All went smooth and didn't have any problems (to be honest the instructions are so clear I think even my kid could have done it).

I followed all the instructions and calibrate the machine without major problems (other than the xyz that failed quite a few times until I read about loosening a bit the screws on the extruder back cover and that was it).

I printed the prusa and batman https://imgur.com/9CRX3iD and even though the quality seemed good I wasn't completely satissfied with it so I run the test from Jeff's "Live Z my way" and pinpointed it to -742 / -745 (for some reason 742 seems smoother to me so I settled on that) https://imgur.com/JOtpLNU

Now, I've printed some more of the SD files in order to further refine the calibrations and stablish a base line to know when the printer is doing good since those are prescliced and tested for the Mk3. So everything here is done via "print from SD" without touching anything else. There are some small problems that I'd like to know how to fix them in order to recognize them in future prints.

Disclaimer: there are lots of images here, since the forums don't have the

Spoiler
tag to hide them, if that's a problem I can edit the post to show them as links instead of embedding them

First I printed Marvin (before pinpointing the Live Z to -742)

And I see some small "shagging" problems :


That's also present on the tips of the batman wings https://imgur.com/6bkssO9

After doing the live Z I printed benchy and the gears bearing.

Benchy looks good with some small problems:



But the bearing is the worse. it has layer shifting and the top layers are fused so I can't move it at all. Although I know the times are approximate, the file stated around 3 hours time printing and it was done in 2 hours. On the rest of the prints the machine is quite quiet but on this one it was pretty loud. It was moving really fast on the infils to the point it made tha machine vibrate quite a bit (it even made the table vibrate) and threw me quite a few false "crash detection errors" on Y. (Edit. Now I just saw that the screw on the Y axis idler is quite loose to the point of almost falling. I believe due to the vibrations of the machine while printing the bearing. The assembly instructions say to not tighten it much so the idler can spin freely, maybe it left it too loose)

Bottom layer:

Top layer:

Shifting and "cracks":

I'd love to hear your insights and help on what I can do to fix this errors...

Thank you very much.

Napsal : 13/05/2018 4:30 pm
Rosparovac
(@rosparovac)
Estimable Member
Re: New user , calibrating the machine & 1st prints - Small problems and doubts?

Some advices:
1. Try to tighten your belts. They lose a little bit after a first few hours of printing. Follow the manual of each axis belt.
2. I see your Z axis is to low. So, try to raise it up via “live adjust Z” I am adjusting every single print on first bigger surface. If filament creating “fences” raise it up. If you seer that lines are not connected low, it down.
3. Those “Cracks” are start of new layer. MK3 crate an ugly start. But you can solve it (maybe) easy: Look at your settings in Slicer PE Print settings -> Layers and perimeters -> Advanced -> Externals perimeters first. If this is checked uncheck it. So, it makes first dome invisible bubble (“crack) inside. Other way is to play with extrusion multiplier or retraction (touchee). If nothing help you can at least set seam position (above External perimeters) to random… that make those “crackers” all over print so it is not so disrupted.

University: MK2S upgraded to MK3 with MMU2.0
Home: MK3
Materials: ABS; ASA; PETG; PET; PLA; Nylon; Nylon Carbon; CPE;
SW: Freecad 0.18; Slicer PE And still generating more troubles than whole forum together.

Napsal : 13/05/2018 9:08 pm
Dibujor
(@dibujor)
Eminent Member
Topic starter answered:
Re: New user , calibrating the machine & 1st prints - Small problems and doubts?

Hey!, thanks for the response!

1- Yeah, after seeing the belt on Y axis I tightened both of them again.
2. Really? think the Z level is too low? where can you see that? (still trying to recognize the problems, first step to fix them).

As a sample this is how I had it when printing the marvin and the prusa/batman (775 left corner on the "Jeff's square"): https://imgur.com/sdsI5AW

And this one is how I have it now (again top left corner): [url] https://imgur.com/9hIJvQj [7url] .

It seems smoother to me and all is connected. Anything above 755 creates those marks you see on the 775 one. Anything below 740 creates gaps between the strands of filament.

So you adjust it every time you do a large print? wow, I thought it would be a "set and forget" thing, just to be changed between firmware upgrades.

3.- Thanks, noted, I'll look into it. All I've printed until now are just the files that come with the sd card, presliced, so I haven't even fired up prusa control or slic3r. I'm most worried about those shaggy parts on marvin. Just printed the whistle on the SD card and it's done it again (kinda) on one of the interior faces, the one further away from the heatbed:

Napsal : 14/05/2018 12:41 pm
Rosparovac
(@rosparovac)
Estimable Member
Re: New user , calibrating the machine & 1st prints - Small problems and doubts?

Your whistle looks good.
The bridge you see at top of printed part can not be way more better because you print in the air. Yeah you can play with cooling and print speed while building (printing) bridges, but every time you print in the air there will be some limitation.
To understand those limitation, I recommend print something like this: https://www.thingiverse.com/thing:1414652

Your image looks good but if you want to understand differences, you must turn the knob much more. I print from ABS and PLA and I need to tune Z distance every time. Sometimes +-0,200 is not enough. Don’t be afraid to print lot off 1 layer 10×10cm squares and try of limits. Only watch out for printer stop printing, while turning low, that mean you too low and another lowering may cause nozzle touch heatbed.

University: MK2S upgraded to MK3 with MMU2.0
Home: MK3
Materials: ABS; ASA; PETG; PET; PLA; Nylon; Nylon Carbon; CPE;
SW: Freecad 0.18; Slicer PE And still generating more troubles than whole forum together.

Napsal : 14/05/2018 3:38 pm
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