So my new printer has been having filament jamming issues. I have tracked this down these 3 little pieces called "heatbreak" They are the threaded sleeve that attaches the heatsink to the hotend and filament passes through this sleeve. These sleeves are metal and the hot filament seems to be glueing itself to the walls if these sleeves. here is a picture of the heatsinks removed from the hotend..



In the above picture I am 2/3 of the way to my solution. The sleeves with the narrow part on them are solid metal with a 2mm hole for filament to pass through. I got 3 heatbreaks for mk8 extruders. these are ptfe lined. I pulled out the ptfe lining and cut them to the proper length. Look how deep the ptfe tube slides into the all metal heatbreak..




Now look at how far the same tube slides into the sleeves I got with the ptfe lining removed..




All the way to the very tip. Now there is a reason for this. the thin part of the all metal part in theory is supposed to promote a good well defined small area transition zone where the filament is in a semi molten state. This might have benefits for abs printing where ptfe lined tubes aren't good all the way to the hotend, but I am only using pla and plan on getting or building an enclosed machine before I even try to satart printing abs. So this seems like a best possible solution for me. But there is one more problem. The sleeves I am using are m6x1.0 and the old all metal sleeves are m6x1 on the hotend side and m7x1 going into the e3d heatsink. Simple fix with a m6x1.0 thread repair kit..





Instead of thread locker I use some high quality thermal paste here..



and here..



And I put it back together with some clear ptfe tubing instead of that white stuff. I think it looks better..




Hopefully I will have some pictures to post of some awesome multi colored prints soon.