RE: How to print with PCL (Polycaprolactone) filament?

For sure I am a bit late with this! I was looking for the same information and I found your post. There is very little documentation about PCL printing on the web... I also bought a PCL spool; it was discounted so I thought that the product wasn't selling because it was difficult to print. I was wrong : PCL is very easy to print! Here is what I learned :

1. I didn't find any profile for PCL in the Prusa's Slicer nor in the MK3S interface, adding them would be great.
2. The filament I used was rated for 70 - 140 C.
3. I preheated to 140C for material insertion but the machine refused the insertion. That low temperature was an issue : I then decided to preheat for a PLA profile fearing that this «high» temperature might «bake» my PCL filament. It worked fine : the polymer was quite liquid at the end of the extruder but I didn't notice any modification caused by the 215C temperature.
4. Then I adjusted the nozzle temperature to 100C and tried to extrude it. The machine refused asking me to «Preheat first»!
5. I prepared my file and specified 100C as the nozzle temperature. Nothing came out of the extruder so I raised it to 140C without success. The head was moving but it was like the extruder refused to move. I don't think it was caused by the temperature being to low for being extruded since I got no grinding mark on the filament when I pulled it out. I think the issue is with the machine Firmware...
6. At 180C I got my PCL out of the nozzle and I was able to print my gcode.
7. I didn't heat the bed.
8. I activated the fan full speed at the first layer and kept that setting for the entire process.

The results :

1. I got nice looking parts, the layers were very subtile, almost polished. I think that is because the plastic stays more «liquid» and have the time to blend with the layer below.
2. With a layer height of 0.1 mm, I specified a 0.7 mm top wall thickness. It wasn't enough : at some places small holes are visible on the surface. I presume this is caused by the very «fluid» behaviour of PCL at that temperature. I think that a 1 mm thickness would be enough to avoid the issue.
3. That plastic is fantastic!!!! It sticked well to the bed. My parts are somehow soft and resistant. I can twist on almost 180 degrees a 5 mm thick rectangle without breaking it.
4. Finally, the best thing is that the waste material can be used as putty for other jobs. Heat it in boiling water and you will be able to shape it with bare hands. Once cooled, it will be shock resistant almost like PA (aka Nylon).
5. At 30$ (canadian) for a 1 kg spool, it is a nice bargain. Amazon.ca sells PCL granules at 23 $ for 0,45 kg...

Hoping I am helping some fellows!

Firmware minimum temperature - 170c

The stock MK3 software has safety limits for lowest temp the extruder will allow extrusion (don't want to burn motors) - it is 170 C - so you can't print at lower temps without a firmware (code change and recompile).  This post caught my eye - I'm looking for a super-soft flexible plastic.  Might have to look into this PCL thing.

RE: How to print with PCL (Polycaprolactone) filament?

Yesterday I did another print with PCL and it failed, I'll send pictures later. The cooling seems to be an issue.

Thanks Dan for the confirmation about the minimal temp. Yesterday the extruder stopped when I dropped the temperature to 170. I will try again with 172...

For now my plan is to retry my yesterday's failed print and I will try a slower printing speed in order to give it the time to cool a bit.

Dan : I would not qualify the PCL as supersoft... It is not an elastomer. The prints are rigid but they don't break when we forced them and the go back to their initial shape...

PCL = low temp filament for pens

Yah, the safeties kick at 170c = so you have to be over that before the extruder will try.  Good luck with your PCL experiments 🙂

RE: How to print with PCL (Polycaprolactone) filament?

I recently started printing with PCL filament for a research project and had the same problem of being unable to print with my PRUSA Mini+ below 170ºC. At the beginning I didn't know why the printer wasn't extruding material at 140º (as it was the temperature recommended by the manufacturer). Then I found this blog topic and understood the origin of the problem. Thank you very much @burcadus and @dan-rogers for your comments, they were very useful for me. 

I then tried to print at 175ºC as you did and it worked well. However, due to the detailed shape of my 3D model I needed the filament to be extruded at cooler temperatures as at 175ºC it didn't have time to cool down from one layer to another (even reducing the print speed drastically). Therefore I tried to find a solution to overcome Prusa's safety features to print below 170ºC, and I found one. You have to add the custom G-code line "M302 S120" to the Start G-code of your print. This feature decreases the minimum extrusion temperature to 120ºC istead of 170ºC (you can find more info here: https://marlinfw.org/docs/gcode/M302.html ). If you need to lower even more the safety temperature, you can lower the number after the "S", but I wouldn't recommend it for PCL filament.

For adding the "M302 S120" G-code line to your print you have to:

1. Go to the "Printer Settings" tab on top of the Prusa Slicer interface.

2. Go to the "Custom G-code" tab on the left.

3. Scroll down until you find the text "; intro line" on the "Start G-code" window and insert the line "M302 S120" under it.

This way, once you slice your model (with your desired nozzle temperature, e.g. 140ºC), this custom G-code line will be added and the printer will be able to extrude at lower temperatures than 170ºC. I tried it on my Prusa Mini+ and it worked well at 140ºC.

I hope this will be useful for anyone that wants to use PCL filament on their Prusa printer. Remember as well to lower the printing speed to ~10mm/s to get better resolution with your PCL filament.

PD: Remember to remove this G-code line or to use another printing profile when printing with other materials with higher melting temperatures. As a recommendation, I would create a new printing profile with the custom G-Code line so you can choose it when you print with PCL filament. 

RE: How to print with PCL (Polycaprolactone) filament?

Does anyone know how to change print settings for printing single one layer lines of pcl 

RE: How to print with PCL (Polycaprolactone) filament?

Thank you everyone for the most excellent replies.
Chris Shaker

RE: How to print with PCL (Polycaprolactone) filament?

If what you want to do is simply extrude lines on the build plate, I would recommend using FullControlGCode ( https://fullcontrolgcode.com/). It's a free software you can use to control very precisely all printing paths. It requires no coding knowledge and it's pretty easy to use.

RE: How to print with PCL (Polycaprolactone) filament?

I have the same issue. Did you figure out how to solve this problem? 
Thanks.