Deformations and gaps
Hi all,
after "successfully" assembling my MK4, I printed two models. One is a Prusa logo plate, the other a test object, both printed with Extrudr NX2 PLA. The quality is unfortunately underwhelming. The bars (similar to the lower border of the eg. A on the logo) are deformed and show gaps that look like the surface has split. Likewise the pins - which seem vertically rather nicely straight - are all but "square" when viewed from the top.
I am pretty sure there is something I can do about these issues 😊 However, having absolutely no experience with 3D printing so far, I have no clue what to look for (which terms to search for when trying to find solutions) or what might be wrong there.
Hope someone can help! THX and CHEERS!
Best Answer by Neophyl:
Well your circles are not circles. SO that would highly suggest either your pulleys are loose on the stepper motors or you belts are horribly tensioned.
Given you said you have previously had good prints then I would check the small grubs screws on the pulleys. Many people do not tighten them correctly (the order of the main screw and the 'set' screw is important). When not done properly they can loosen and then you have play in the back and forth.
You might have more things wrong as those are some seriously bad looking prints but start with your pulleys and belts. Then go from there.
RE: Deformations and gaps
Well your circles are not circles. SO that would highly suggest either your pulleys are loose on the stepper motors or you belts are horribly tensioned.
Given you said you have previously had good prints then I would check the small grubs screws on the pulleys. Many people do not tighten them correctly (the order of the main screw and the 'set' screw is important). When not done properly they can loosen and then you have play in the back and forth.
You might have more things wrong as those are some seriously bad looking prints but start with your pulleys and belts. Then go from there.
RE: Deformations and gaps
Thanks for this first hint! It seems the belts were indeed too loose (never had any good prints, the pictures show the first and only 2 prints done so far). I have now adjusted tensions and will give an update here once I am able to run a test print with the new tensions. Just wanted to give some feedback right away.
PS: I could not get the belt tuner app to work well on my cell phone (S23). Measures were not updating at all, jumping from 150 to 70 without changing anything and back again and so forth. Tried Spectroid app but essentially could not get things providing useful feedback. I have now simply used the app on the computer with a headset mic positioned at the right locations - and that did work then.
Agreed, check those grub screws, make sure they meet the flats.
If you have PETG make your next print this:
https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus
It MUST be printed in Prusament PETG or the spring tension will be wrong.
(Although designed before the MK4 was thought of the values are an excellent starting point. Then use the app for fine tuning.)
Cheerio,
RE: Deformations and gaps
Printing the tension meter is on my TODO (PETG ordered 😀 ), but I figure with the result as shown in the pictures of my original post, that meter might not work well enough. I hope the latest adjustments to the tension are going to help with that issue so I then just need to fine tune/confirm tension after printing the meter successfully.
RE: Deformations and gaps
Finally have been able to run a test with the newly adjusted belts and the difference is massive! 👍
The immense deformations are basically gone and the whole print is decent now. I am sure there is still plenty of things to calibrate and play around with - and suggestions/hints are for sure always welcome 😬 - but I think it's a starting point that I can now deal with!
Thanks a lot for the quick help right on spot! Tremendious!
CHEERS