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Is an M4 thread too small to use with PEEK?

Posted by HereinCS

HereinCS

Is an M4 thread too small to use with PEEK?
April 13, 2011 10:12PM

Registered: 13 years ago
Posts: 46

I'm thinking of using an m4 thread for the hot end and screw that into a peek rod. Is it too small? Should I go with m6?

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mlagana

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 03:47AM

Registered: 14 years ago
Posts: 323

you mean the supports going down from the extruder base to the peek block? you would be better off going smaller, m3 could do the job fine and won't transmit as much heat up to the area of the extruder you want cold

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VuRaL

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 04:49AM

Registered: 13 years ago
Posts: 17

Well, if it is geared or wade style. M4 rod would go out of peek with the preasure you apply to your flament. But if you are going to use 1.75mm feed filament and check temperature very carefuly. M4 might work.

In my experience, even M6 goes out of PEEK in some cases.

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brnrd

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 06:44AM

Registered: 13 years ago
Posts: 1,780

If you drill an M4 screw for a 3 mm filament, I think that the walls would be too thin. Also, it would be better to screw the peek rod into a brass tip than the other way around. PEEK will expand when it gets hot. This could result in a leak. Also, there it's not as slippery as PTFE. Most designs using PEEK includes a PTFE liner to reduce friction. This would require an even bigger thread. See Adrian's hot end designs in the wiki.

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HereinCS

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 10:22AM

Registered: 13 years ago
Posts: 46

That's interesting. Due to the slight expansion of the PEEK, it's better to screw Peek into metal rather than metal into PEEK? That seems like good advice.

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makergear

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 11:07AM

Registered: 14 years ago
Posts: 31

@HereinCS Are you thinking about something like this. Something along those lines should work for 1.75mm ABS. IIRC it uses an M4 barrel.

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HereinCS

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 11:26AM

Registered: 13 years ago
Posts: 46

Yes. Similar to that. Do you have any problems with the threads leaking? Does the PTFE to all the way down to the tip or just to the end of the PEEK section?

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makergear

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 11:32AM

Registered: 14 years ago
Posts: 31

That is solid PEEK, no liner. So, if you want to use it with PLA, you'll need to actively cool the PEEK. The issue with PEEK and PLA is not friction, it is heat. PLA softens at a lower than ABS and gets sticky. As long as the PEEK temp remains low enough it will work with ABS and PEEK. Temp gets too high it won't work with either...

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HereinCS

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 11:49AM

Registered: 13 years ago
Posts: 46

If you don't mind;

1. Doesn't black PEEK have 5x the thermo conductivity of plain PEEK? Would your heat issue be lessened with plain PEEK?
2. I like the look of black PEEK, but plan to use a PTFE liner to lessen the heat transfer. Was there a reason you didn't use the teflon liner?

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makergear

Re: Is an M4 thread too small to use with PEEK?
April 14, 2011 12:48PM

Registered: 14 years ago
Posts: 31

1) Do you mean a different grade of PEEK?
2) I made that in Sept., only 1.75mm ABS was available at the time.