Filament Drive Pinion gear slipping on shaft

Ask the MakerGear community for assistance...
Post Reply
airscapes
Posts: 387
Joined: Wed Jan 31, 2018 11:36 pm

Filament Drive Pinion gear slipping on shaft

Post by airscapes » Thu Dec 19, 2019 11:07 pm

Not sure the cause, be it the grease I packed in the gear box or what but:
I printed and replaced the filament drive housing with on off thingivers that was altered to tighten up the filament path for flexible as I was having issues with the Ninjaflex not consistently extruding. In hind sight it may have been the gear problem I am about to explain.
The new drive housing has a filament path of exactly 1.75 which I cleaned out with a 1.75mm drill bit, I did not open it up to 2mm like the stock unit.
It worked well with NF and I got the parts printed that I needed. I then wanted to print something else in PLA and grabbed a old roll of MakerGeek filament. There was apparently a bend in it and it jammed after just a minute. After some head scratching I realized the stepper was running but the filament gear was not turning. After pulling the drive and gearbox off I found the pinion gear had slid down the shaft of the stepper. I was able to pop it off with a pick, clean all the grease off and inspect for cracks. There is no damage and support did not know if this was press fit or something else. I did a search here and found one post suggesting it is held on with adhesive. So I put it back on with a drop of CA and it is currently printing.
The question is: Is the CA the correct product? Anyone ever run into this, any other suggestion other than replace everything?
Picture is the gear when the unit was first removed.
pinion gear.jpg

thunderbt3
Posts: 105
Joined: Wed Apr 09, 2014 11:36 pm

Re: Filament Drive Pinion gear slipping on shaft

Post by thunderbt3 » Thu Dec 19, 2019 11:17 pm

The gear is slip fit onto the shaft. Green loctite is what you need to get back rolling.

I would first clean everything very well to isopropyl alcohol to make sure the gear hasn't cracked. Apply a bit of green locktite to the shaft and slip the gear back on. It takes about 24 hours to fully cure.

airscapes
Posts: 387
Joined: Wed Jan 31, 2018 11:36 pm

Re: Filament Drive Pinion gear slipping on shaft

Post by airscapes » Fri Dec 20, 2019 1:59 am

Did all that, cleaned and inspected, just use CA rather than locktite, only have the medium strength stuff from HF and didn't know if it would be too thick to do any good. If it comes loose again I will use the locktite.
Thanks for the info!

User avatar
ednisley
Posts: 1091
Joined: Fri Apr 11, 2014 5:34 pm
Location: Halfway up the Hudson
Contact:

Re: Filament Drive Pinion gear slipping on shaft

Post by ednisley » Fri Dec 20, 2019 1:43 pm

airscapes wrote:
Fri Dec 20, 2019 1:59 am
just use CA rather than locktite
Cyanoacrylate adhesives are brittle and have poor shock resistance, which the pinion desperately needs.

Threadlocking adhesives tend to be more resilient, although high-strength versions set hard.

However, if the pinion has worked finger-loose, then no adhesive can secure it to the shaft against the motor torque.

Installing a new pinion from MG is really the only way to go.

airscapes
Posts: 387
Joined: Wed Jan 31, 2018 11:36 pm

Re: Filament Drive Pinion gear slipping on shaft

Post by airscapes » Fri Dec 20, 2019 5:15 pm

I ordered one to have on hand as I didn't hold much hope that the CA or locktite will work. I would have assumed it was a light press fit not held in place by adhesive. Also a little disappointed that support could not tell me how that gear was affixed. The person who answered did not know and asked one of the builders. Since this is a complete unit purchased from china they did not have knowledge of the gears installation.
After cleaning I looked at the inside of the bore under high magnification and it appeared to have remnants of a chemical bonder as it was kind or white in places. No cracks or missing metal. It did slide on with finger pressure..

User avatar
ednisley
Posts: 1091
Joined: Fri Apr 11, 2014 5:34 pm
Location: Halfway up the Hudson
Contact:

Re: Filament Drive Pinion gear slipping on shaft

Post by ednisley » Sat Dec 21, 2019 2:25 pm

airscapes wrote:
Fri Dec 20, 2019 5:15 pm
a complete unit purchased from china
To a good first approximation, all electronic & electromechanical components come from halfway around the planet. That's a rant for another time, but just the way things are.
slide on with finger pressure
Yeah, that one's dead.

If you don't have trouble ramming the pinion in place, it's too loose: it should be a very tight fit.

airscapes
Posts: 387
Joined: Wed Jan 31, 2018 11:36 pm

Re: Filament Drive Pinion gear slipping on shaft

Post by airscapes » Sat Dec 21, 2019 4:35 pm

CA is holding, but have not had anything jam, just printing little 2 walled squares playing with Prusaslicer 2.1.1 which seem like it will be the software to use in the coming year(s) Liking the results better than simplified 3D ver 4.01.. Not sure that S3D has much of a future.. seems like they were bought by someone with no clue..

Post Reply