Grégoire Saunier

ASA is shrinking more than recommended PETG so you have to compensate in the slicer (a few percentage). Also make sure your are not printing too fast (parts become matte) and that your speed profiles doesn't jump between speed more than 30%. For example, printing perimeters at 50mm/s and infill at 200m/s will create bad layer adhesion, no hotends can supoort such temperature differences.

The calculation is only an approximation but in reality it's more complex (plastic elasticity, back pressure in the nozzle, etc.). So it's good to repeat until it's spot on.

Yes same things, I will update to have the same naming everywhere. They are M4.

Check that no cables or printed part are blocking

It is possible that some PETG have slightly different shrinkage coefficients but it is not the only possibility. Printing too fast may affect this as well. I don't know if you are using the original smooth rods but they may have a different tolerance value. The printer you are using can also affect this (belt path issue for example). Finally the slicer plays also a role, please stick to the recommended settings, including the slicer. The best way, but more expensive, is to buy a reamer just bellow 8mm, like 7.95mm.

We are still recommending the Bear calibration firmware for the calibration steps and go to latest Prusa firmware for daily prints.

Hi Rob, I am really sorry to hear that and thank you for the feedback. Could you please contact the reseller to get replacements? Keep me in touch if they can't solve your issue.

Hi Ben. In the latest firmware 3.12, Prusa has implemented a new safety for the hotend and it is very precise. If you are using a different hotend than original V6 then you might get a Thermal Anomaly error. Prusa is collecting data from users with E3D Revo hotend to make this hotend compatible, if this is the hotend you are using and you like to help, please share your data here: https://github.com/prusa3d/Prusa-Firmwar...

Hi and thank you for your feedback. The design is already made to be tight and avoid the hotend rotating. This is not a common issue so here are some point to check before:

1. Did you use PETG? Plastic does creep over time and some filaments more than others. PETG doesn't creep much but Nylon do it a lot.

2. Sometimes if the extrusion multiplier is a little too low it could affect this. Check if you see signs of underextrusion on the parts.

3. In some special circumpstences, like a hotend fan failure, the heatsink could get warm enough to deform the parts. It is a serious issue and the firmware have safeties for this but maybe you had this in the past.

4. The extruder is designed for genuine V6 hotend but I know many are using clones. If you are running a clone it might be the manufacturing tolerances that are slightly different that E3D hotend.

Please keep me in touch if one of those points is a potential cause for you.

I am happy you could solve it. I can see how this could be an issue so I will make an update on the printed part. Thanks for reporting it.