ptfe aging

Hi all,
hope I've got the right group.
Does PTFE tubing swell with age/temp?
Wondering as I was able to cold pull the nozzles 9 months ago but now
it jams all the time.
Oh, I've got PTFE going all the way to the nozzle. Home made hotend.

PTFE will soften and deform at nozzle temperatures. That is one reason why most designs that use PTFE liners avoid going all the way to the heater block.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

PTFE creeps/flows under pressure also, and this get worse with higher temps.

If the PTFE is under pressure and has the room to deform it will. I use PTFE in my Merlin hotend design and it goes all the way to the brass nozzle. This works because i make sure the PTFE is stabilized sufficiently (thtreaded) and that any deformation on heatup is taken care of after initial assembly and before real printing starts (reaming after compression and heating).

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Mmm,
thanks folks.
Srek, how do you ream/bore the ptfe when the hotend is on?
2mm piece of wire?

Maybe I'll splash out and get a e3d lite.

Thanks again.

Actually Srek, how did you thread the ptfe? or did your hotend have
a smaller ID than 4mm so you could cut a m4 thread?

Threading PTFE is no fun. I used a 4mm hose, stabilized it with a 2mm rod on the inside and cut the thread on a lathe.
As for reaming, it does not have to be hot. After heating the pressure will have it deformed and you ream it while cold.
Apart from that, the merlin ihotend stays cool enough to touch at the upper end, even at ABS printing tempertatures.

Edit: alternatively use a 4mm PTFE rod and drill the hole once the part is screwed in the PEEK.

Edited 2 time(s). Last edit at 01/21/2017 10:09AM by Srek.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

E3D lite has teflon going down to the block so it is limited to printing PLA and ABS (and maybe a little iffy for printing ABS). The V6 teflon stops at the heat break.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]