Extruder head keeps coming off

[IgorAntunov]

Max temp never exceeds 210c, extruder head forces its way out.

After a day of use, this happened:



I tried redoing the internal thread and then screwing it back in, after a few minutes it just did it again, the hot PLA forces the head off. I think the thread was busted from the start, I ordered a new extruder (same type) but I fear it will happen again.

Should I make/order an all-metal one? Is this extruder crap by design? What am I doing wrong?

[john]

Both a same type extruder and an all-metal one are OK. Please assemble it carefully.