PCL (polycaprolactone) extrusion tips

Polycaprolactone (PCL) can be a challenging material to extrude with the Filament Maker because of its low process temperature (typically around 80°C).

The following information is based on our experience with PCL, as well as customer feedback. As always, due to PCL coming in a variety of grades, the information provided here might not exactly apply to your personal case.

1. The main challenge

In general, PCL must be processed around 80°C.

Our purge/transition materials (like PLA, HDPE, Devoclean MidTemp EZ) must be processed around 180°C, at least.

There is no thermal overlapping, and the barrel cannot be emptied between runs. 

At first sight, PCL is incompatible with our maintenance recommendations. How can we work around this obstacle?

2. Option A: purging with PLA

When processing PCL, I managed transitioning from PLA to PCL at 170°C. In these cases, the grades of PCL could withstand such a high temperature. This might not apply to all PCL types. The procedure was:

  1. Filament Maker initially full of PLA
  2. Start extrusion at 170°C
  3. Transition to PCL
  4. Set the temperatures down to 80°C (or other working temperatures) - without stopping the flow
  5. Process PCL
  6. Set the temperatures back on 170°C - without stopping the flow
  7. At 170°C, transition to PLA
  8. Switch off

3. Option B: Skip the purge

Maybe your grade of PCL will not degrade majorly nor clog the extruder when left inside the barrel during shutdown.

In that case, you would have the freedom to start extruding directly at 80°C (or other PCL settings) with a machine full of PCL, and switch the system off without purging.

This sounds reasonable from a maintenance standpoint, since PCL is very easy to melt, but we have not tested this procedure.

There is still a small chance of clogging the barrel.