Polycarbonate on the Prusa i3 MK3S

Apologies for the lack of updates, I've been on holiday and getting ready to move house.

I spent a few days in Malta, which was lovely, I really enjoyed the collisions of Mediterranean, Arabic and English cultures. I found some interesting food out there, specifically the lovely Pastizzi, flaky filo pastry filled with creamy slightly tangy ricotta, just a wonderful breakfast pastry.

Travel aside, after a bit of a break from developing material profiles for the Prusa i3 MK3S I finally got back to playing with new materials. I had a couple of samples of polycarbonate that I have had for a while, so I decided to give them a go. I had a sample of the PC-ABS alloy from Proto-pasta and some PolyMax PC from Polymaker. I found that especially for the PolyMax PC a very conservative amount of cooling fan really helped with the print quality, especially on small details and short layer times. The use of a cooling fan probably does not help the layer to layer adhesion strength, so I have also developed a profile that does not use a cooling fan at all.

Polymaker PolyMax PC
The key to these materials seems to be printing them very slowly, with a minimum layer time of even 40 seconds or more.

As you may or may not know, I am a big fan of the 'purgebubble' method in which you heat the tool to a lower temperature (140°~160°) than would be useful for extrusion, then do the mesh bed levelling and then once the tool is at the start of the purge line it then heats up to the proper printing temperature. This accomplishes two things, it prevents blobs of filament being deposited onto the build plate during mesh bed levelling and it produces a blob of filament at the start of the purge line, which once the tool starts to move helps to remove excess material from the nozzle itself.

I use this method for every material that I print, it is especially helpful for materials that are stringy or like to blob up on the nozzle. However I could not get a clean print going when I was developing the Proto-pasta PC-ABS alloy, I think that this material just clings to the nozzle more resolutely than other materials, leading to issues with the first layer. To this end I have uploaded a printer profile that does not use a purgebubble.

I have some more of the Proto-pasta PC-ABS coming, so I hope to refine that profile slightly.

 Proto-pasta PC-ABS alloy

As always the GitHub repository with both of these material profiles can be found here. 


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