Upgraded MK3 --> MK3S Melted Parts
I upgraded my MK3 to the MK3S a few months ago. The parts I printed myself for the extruder case are generally marked R4 (revision 4). I managed to get a medium size PLA blob on caught on the hotend. The resultant heating of the PETG around the hotend caused the extruder body to melt a bit and allowed the hotend to drop a bit.
I am attempting to print new parts and put it back together. However, the parts are marked R5. Does anyone have knowledge of whether there were significant changes to the extruder body in R5? I want to change as few parts as possible, but I don't have any information to tell me how much to print and replace.
Any help would be appreciated!
RE: Upgraded MK3 --> MK3S Melted Parts
The new extruder parts were updated to... prevent them from melting.
I think specifically the portion that holds the PINDA
RE: Upgraded MK3 --> MK3S Melted Parts
I use a E3D Silicone Sock, mainly to keep the hotend clean. Other benefits could be keeping the print temperature more constant and keeping heat away from the hot end shroud. As ABS doesn't work for me I printed that in orange PETG (an ABS original is part of the upgrade, but alas in black.
Yesterday I had to dismantle part of my i3MK3S extruder assembly to get some stuck filament out. In the process I found that a part of the Extruder Cover had melted. Typically just above a cutout in the Silicon Sock. This part (R4) was printed with the Prusa PETG that came with the upgrade. I used the printer for about a year, printing mainly PLA, before installing the sock. I didn't notice any deformation before, but as I had no reason for close inspection, I could have missed it.
Could it be the sock concentrates the flow of hot air from the hotend gives this result? In this case it might be useful to try to block the unneeded cutouts of the sock.
Just now I printed the R5 extruder-cover part and as it is thicker at this point, it could solve the problem.
RE: Upgraded MK3 --> MK3S Melted Parts
If you download the whole part set, you find find out that only 2 parts are in R5 revision, the rest is still R4.
It is extruder-cover and extruder-body. Not sure about fan-shroud.
If this works while printing the whole set, it should be also applicable for replacements.
Anyhow, if you proceed, let us know, I also plan the replacement in near future 😉
Miloš
RE: Upgraded MK3 --> MK3S Melted Parts
Looking at https://github.com/prusa3d/Original-Prusa-i3/tree/MK3S/Printed-Parts/STL, there are more updates since the introduction 6 months ago, but AFAIK nothing related to hot-end heat problems.
I noticed the my PETG fan-shroud is affected too, as it is next to another sock cutout. Maybe I should build a temporary printer enclosure and try to print it in ABS again. I could profit from the current local heat-wave :-).
Greetings,
Fred Jan
RE: Upgraded MK3 --> MK3S Melted Parts
There are most probably the small changes for the time, but if I just take a look to the revision parts, it seems only those 2-3 are not comaptible.
You will be definitely able to print the fan shroud from ABS also without the enclosure, it is not a must. I would recommend to print slower, maybe better print two fan shroud parts at once. One is always good :-). Close the doors and windows to the room, so the air and temparature is stable. It is not a long time.
Miloš
RE: Upgraded MK3 --> MK3S Melted Parts
^^ ABS fumes in an enclosed space are not exactly good for you. Don't plan on being in the room during the print, and have a plan to air it out after.
Printing ABS. Was: Upgraded MK3 --> MK3S Melted Parts
You will be definitely able to print the fan shroud from ABS also without the enclosure, it is not a must. I would recommend to print slower, maybe better print two fan shroud parts at once. One is always good :-). Close the doors and windows to the room, so the air and temparature is stable. It is not a long time.
I did print the fan-shroud before with ABS, but it wasn't good enough, very rough at the top end. The idea was to create a makeshift enclosure, just for this part. Usually I print with PLA and occasionally PETG. So I used the current very warm weather (almost 30 degrees inside), closed of a Lack table with carton, put the printer inside. Printed two shrouds, to keep the print speed low, as you suggested. The result is much better, I guess good enough for me.
Temperature inside the box at the top was about 47 degrees Celcius, higher closer to the head bed, which was 110 degrees, Prusa ABS standard. Reverted to standard setup afterwards, as the high temperature isn't good for the electronics. The ABS fume wasn't that bad for once. Nightly ventilation is required with this weather anyhow.
Greetings and thanks for the suggestions,
Fred Jan
RE: Upgraded MK3 --> MK3S Melted Parts
I printed the MK3s upgrade parts myself using PolyMaker PolyMax PC, layer hight 0,1 mm, perfect fit without any postprocessing.
(PolyMaker PolyMax PC is a polycarbonate filament)
No melting issues!!
Disclaimer: I have no interest in the brand PolyMaker or any other filament brand, my favourite filament is Amphora 3300 also known as ColorFabb nGen.
This is due to the fact that I need for all my prints the safety regulations sheets from some strange agency, called the FDA..:):):)
Dick