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I tried printing @ColorFabb’s 2.85mm PLA/PHA material but on every print the filament got stuck in my hotend. I kept trying with a bunch of different settings such as the print volume per second, temperature, … but still got jams in the hotend.

I wondered why I have got this problem with the 2.85mm PLA/PHA because printing with 1.75mm and 3mm material works just fine (Setup with hexagon hotends and bulldog xl extruder). Also printing with Colorfabb’s 2.85mm XT worked just fine.

So I talked to other 3D printing enthusiasts and also decided to contact the Colorfabb support. At all I got very good advices from both sides. The main issue in printing with the 2.85mm filament was that heat travelled up during print wich caused the filament in the hotend to expand (from 2.85mm to ~3mm) and generating more friction.

Jos of the Colorfabb support also sent a link to the E3D blog about the design of a hotend. In this blog post is also a picture which shows what parts of the hotend should actually be hot and which not. And there has been my problem. I had a too small fan for actively cooling my all-metal-hotend so the temperature went just up in the filament. After adding a better cooling system the 2.85mm PLA/PHA printed perfectly as known from Colorfabb’s filaments.

A very big thanks to the Colorfabb support and a few 3D print enthusiasts. I am looking forward printing a lot with Colorfabb’s filaments ;).

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I made pretty much similar experience. Two weeks ago I put a E3D v6 Hotend on my Ultimaker 2, I am very happy printing ABS and cheap PLA (3mm diameter), but Clorfabb PLA/PHA is jamming quite a lot and I get quite a lot underextrusion, especially when a second part is started or a lot of retraction takes place. What modification did you do to the cooling system. I read aswell that heat sink paste could be a good improvement.

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I used two 40mm fans, and put them directly in front of the heatsink without any air duct. I just made a few shields around the fan to define the direction of the airflow. I also used a separate 12V power supply to power up my fans because my actual hotend-fan-output is not capable of powering two fans. As you mentioned that heat sink paste should be a good improvement. In water cooled hotends that would help in certain situations but if you have a air cooled hotend i can’t see a reason why you should use heat sink paste. If you have the skills to build a water cooled hotend it’s probably the best way to get rid of heat issues but if you would mount a good fan it should probably help. If you want to have a good explanation email of those heat issues I can forward an email from Colorfabb which helped me quite a lot. Just send me your email as a private message (https://www.3dhubs.com/vienna/hubs/bernhard)