Here is another question I answered from the now defunct Makers StackExchange.

Question:

I’ve seen a lot of ABS and PLA printing, but haven’t seen mention of other plastics.  Do any machines current support polycarbonate as a material? Are there reasons it’s not currently, or commonly, used?

My Answer:

One reason is melting point: PLA melts at around 180°c and ABS melts around at around 220°c, while Polycarbonate melts at around 300°c. This extra temperature creates a couple of problems:

  • Higher operating temperature for the printer means higher energy use.
  • It also makes it much harder to insulate the hot-end from the rest of the printer. You can accidentally warm up parts of your printer (like your extruder) to the point where they become soft (especially when your printer parts are made from PLA).
  • PTFE (teflon) used in many hot ends as an insulator (to separate the hot parts from the parts you want kept cool) also melts at around 300°c and some places suggest that it starts to break down at about 260°c and release toxic fumes.

However, despite these problems you will be able to find a few people around on the internet that are experimenting with Polycarbonate and working on solutions to the above engineering challenges.