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Is this heat creep?  

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sin
 sin
(@sin)
Active Member
Is this heat creep?

I just had a print fail because of a jam and this is what the filament looked like behind the extruder door with the bondtech gears:

Am I correct in thinking this was caused by heat creep which caused the filament to become soft enough to bend that far up the hotend?

I am running in a hot environment, ranging from 30-40°C, so I am not surprised. I just want to be sure this is my problem before troubleshooting further.

I recently replaced the heat break to the original E3D version because I was getting clogs near the nozzle. I believe the new heat break is indeed doing its job now, and has passed the problem further up to the bondtech gears.

Other than simply waiting to print when the temperature lowers, I'm going to try bumping up my print speed to raise the volumetric flow rate, as well as reducing retraction. If anyone else has other suggestions I'd love to hear them!

Posted : 22/07/2019 2:02 am
Dave Avery
(@dave-avery)
Honorable Member
RE: Is this heat creep?

hotter hot end temps, more air over heatsink ( new and/or external cooling fan), air conditioning 🙂 ,  slower extrusion speeds ( less pressure on filament)

Posted : 22/07/2019 2:15 am
sin
 sin
(@sin)
Active Member
Topic starter answered:
RE: Is this heat creep?

I do have a fan circulating air now, which should help!

I'm interested in your suggestions of hotter nozzle and slower speed. My guess was the opposite... to as quickly as possible pass the filament through the hot end with the lowest temperature the filament allows. Particularly because I got that bend so high up -- I can't believe the filament was pliable near the gears! 

I can see how raising the hot end temperature could allow the filament to flow with less resistance, but this particular roll of PLA I'm using seems plenty oozy at 210°C, so I've actually got it dialed back to 205°C at the moment.

If my tests fail I'll try the other route to see if lowering resistance keeps things moving.

Apologies for not mentioning it in the first post (and I can't edit...) but this is a normal roll of PLA that is having the bend problem.

Posted : 22/07/2019 3:29 am
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 --
(@)
Illustrious Member
RE: Is this heat creep?

The extruder heat creep is generally said to be exacerbated by the new MK3S design (not as well ventilated as the MK3 design).  That adding a heat sink and/or fan to cool the motor can help reduce motor temps to essentially eliminate the problem. A single 40x40x11mm heatsink attached with good thermal tape dropped my E-motor temp about 8c, and there is room for four of them.

Thingiverse has a user model for a fan shroud many have found useful, reported to drop motor temp by 25c.  Parallel a 5v fan with the cooling fan (leave the new fan's tach wire floating).

https://www.thingiverse.com/thing:2975582

 

Posted : 22/07/2019 6:49 am
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