Low extruder torque -- is that the pinion gear?

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insta
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Low extruder torque -- is that the pinion gear?

Post by insta » Mon Jul 17, 2017 3:10 pm

I've completely replaced the nozzle, and it's still struggling to push PLA through @ 225C. It's an older extruder motor, still a 6-pin JST, but a few years old and of the right vintage. Before I tear my dual setup apart to check, is that behavior explained by the bad pinion?
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ednisley
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Re: Low extruder torque -- is that the pinion gear?

Post by ednisley » Mon Jul 17, 2017 3:32 pm

insta wrote:explained by the bad pinion?
The planetary gearbox failures seem to be a completely snapped motor shaft, which would work perfectly right up until it doesn't work at all.

Given how much filament you run through those printers, perhaps the hole through the drive block has worn enough to allow the filament to snag above the drive gear or bend below it?

Or the spool isn't turning freely any more and (not quite) stalling the drive?

I'd test all things simple & mechanical before even thinking of anything complex & electrical (or, shudder, software).

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insta
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Re: Low extruder torque -- is that the pinion gear?

Post by insta » Mon Jul 17, 2017 4:42 pm

No, there's a separate failure mode. One of the batches of pinion gears was made too soft, and they wear out. I just don't remember what happens when they do.

edit: to follow up, this is me trying to feed a foot of filament directly into the filament drive. There's nothing to snag.
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Spotopolis
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Re: Low extruder torque -- is that the pinion gear?

Post by Spotopolis » Mon Jul 17, 2017 6:28 pm

I had one of those soft pinion gears a couple of years ago. The biggest symptom was constant clicking from the extruder motor regardless of tension settings or extruder temperature. It got worse until it finally wouldn't feed at all, and when I opened up the gear housing, the pinion barely had any peaks left on the gear.

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insta
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Re: Low extruder torque -- is that the pinion gear?

Post by insta » Mon Jul 17, 2017 6:45 pm

That sounds like it, dang it.
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jimc
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Re: Low extruder torque -- is that the pinion gear?

Post by jimc » Mon Jul 17, 2017 10:38 pm

yes it will click and youll get some under extrusion. i dont think mine really got weak. it just started skipping and making the click. you'll also notice you will slowly have oozing issues that get worse and worse since the retraction is sloppy and not to the distance that it is really set to. i have even had some of the new hardened ones wear. not enough to click and go bad but when i took it apart there was significant wear

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