While out on our euro-trip the MK2.5 upgrade for my beloved Prusa printer came in. I had finally plowed through enough chores to get started on the upgrade when I realized you need to print everything first. I ordered this 6 months ago and could have easily lined up all the replacement parts by now. Oh well, shame on me for not reading ahead. They did include a 1/2kg spool of PETG to print everything with, so lets get that started.
Now I know my bed is shot, thats why I wanted this upgrade. It gives you a double sided spring steel printing bed. Still, I couldn’t get the first layer of Prusa supplied PETG to stick to save my life. This was my best attempt, and this was pretty bad.
I switched to some Push Plastic brand PETG that I had around and it initially looked golden. Soon though I ran into issues. There were z-layer striations in many of the prints like the nozzle was partially jamming. I thought some of the odd and difficult to print features were to blame and broke up the prints into smaller batches. These batches had problems too. I spent 2 days printing with different settings, cleaning out the nozzle, replacing the nozzle, taking everything apart, switching to PLA, and doing about 10 other things. All I did was get more frustrated and produce a pile of garbage.
I was incapable of producing small parts without error and big parts would completely jam before finishing. These were the most horrible frustrating times I have ever had with a printer. Even worse than my monoprice, and that is saying a lot!
I thought the hot end section was damaged, and on one of the tear downs to look for issues, I decided to give the extruder a rotate. I had checked its pin out with a multimeter, and inspected the wires for frays, but a single rotation by hand gave me the clue I needed. It was nearly impossible to turn.
Here is what the inside of a Prusa MK2 extruder motor looks like in case you ever wondered. The bearing on the left is fine, the one on the right is frozen solid. They are a smaller size than the 608 bearings I have around, and that most people use for projects. I ordered some to repair this unit, and contacted Prusa about getting a whole new extruder. If it isn’t too expensive I will eventually swap my repair job for a new unit.
The bearings will be in shortly, but I am dead in the water till then. Once repaired I will, hopefully, be able to finish printing all the upgrade parts, then I can have a whole new extruder setup and print surface. Until then, this is what my poor printer looks like. Never a good site. Nice use of my printed organizer tray. It keeps screws and bits separated and organized when you take something apart.