Hi,

Please take a look at this picture While I am printing melted abs pile up on the top. How can I solve this issue?

Regards,
Nuri Erginer

The top of your insulator needs to be cooler than the glass transition point of the plastic. The molten back-flow then freezes before it reaches the top of the insulator. Normally the PTFE insulator is fastened to the body of the extruder which will take some heat away and the plastic will freeze a few mm above the join to the brass.

Having the bore through the PTFE a much bigger diameter than the filament could also lead to this problem.

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Ok Thanks alot for your advise. I will try and share the results

Regards,
Nuri Erginer

Nuri,
You might also try making a longer barrel of PTFE, with the brass section threaded into the hot end the same depth as you current one. With a longer thermal barrier, the cold end can be much lower than the hot end. Right now your cold end is TOO hot.

Hope this helps.

Mike