Why PETG is recommended by Prusa when printing parts for its printers?  

RE: Why PETG is recommended by Prusa when printing parts for its printers?

Aside from the fact that things like motors also get hot, why would those other parts not benefit from the toughness, durability, and stability of PETG? Why wouldn't they recommend it?

RE: Why PETG is recommended by Prusa when printing parts for its printers?

Posted by: @prusanewuser

I can understand that if it is for the hotend, PETG would be better. How about other parts like those in orange color?

Hotend parts should be printed in ABS or ASA. Especially the fan shrouds and anything near the hotend. PETG will melt and warp.

Solid parts should be in PETG. It has higher strength, greater hardness, and is more resistant to creep than most other materials.

PLA is inappropriate because of reasons above and also low-heat tolerance. Even motor mounts may exceed PLA glass transition (60C).

RE: Why PETG is recommended by Prusa when printing parts for its printers?

Posted by: @nhand42

Posted by: @prusanewuser

I can understand that if it is for the hotend, PETG would be better. How about other parts like those in orange color?

Hotend parts should be printed in ABS or ASA. Especially the fan shrouds and anything near the hotend. 

Really only the fan shroud is high risk of melting and warping on most of the MK4 and XL parts.  It is also about the only part on the mini that has warped for me.  

RE: Why PETG is recommended by Prusa when printing parts for its printers?

The only part I changed on my Mk3 (which is inside of an enlcosure that gets moderately warm, maybe up to 40-45°C) was the fan shroud which is now in PC-Blend and that is rock solid and doesn't budge even when printing at max hotend temperatures. I did not have any problems with any other PETG parts to this day. 

PLA is highly discouraged. It is not just the glass transition temperature. PLA creeps and at higher temperatures it creeps even more. That is also the case for the "high temperature PLAs" out there. There simply isn't a PLA or a variant of PLA which is suitable for anything that has to carry a load or provide stability.

RE:

My main concern is why PETG is recommended to use for printing parts frames outside the extruder. For example, the two orange frames at the ends of the vertical rods, rod holders on the y-axis, etc. Why not PLA for those parts?

RE: Why PETG is recommended by Prusa when printing parts for its printers?

Posted by: @prusanewuser

My main concern is why PETG is recommended to use for printing parts frames outside the extruder. For example, the two orange frames at the ends of the vertical rods, rod holders on the y-axis, etc. Why not PLA for those parts?

Because it's brittle and it creeps even at low temperatures, and it creeps even more when somewhat warmed by nearby motors or by being put in an enclosure. Again, why wouldn't they recommend it? It's not expensive or difficult to use, it doesn't require any special equipment or safety precautions...

RE: Why PETG is recommended by Prusa when printing parts for its printers?

Reading this thread and the other day I was thinking of printing all the parts in ASA due to enclosure temperatures.  I have had a print head failure that partially melted the ASA fan shroud.  

RE: Why PETG is recommended by Prusa when printing parts for its printers?

It is really just the fan shroud which has a tendency to warp or melt. At outmost maybe other parts directly adjacent to the hotend but in my case it was really just fan shroud. Print it in PC-Blend or PCCF and it will never melt again, as long as your printer doesn't catch fire or you have some crazy upgrade nozzle with above 300°C ...