Machined Aluminum Filament Drive

[Rich]

Hi Guys

I seem to be going through filament drives like crazy. With ABS it's about 2.5 drives per roll. Typically the failure is on an overnight build when the model comes loose, apparently sticks up too far, and gets clobbered by the hot end repeatedly, resulting in a loose groove in the drive for the groove mount.

A friend of mine has volunteered to machine a filament drive, as well as an extruder motor mount, out of aluminum.

Is there a reason (other than to say "my machine can build itself") that these need to be plastic? If these parts were metal, would something else break instead?

Thanks, Rich

[benavery]

I would try to better understand what is happening to cause the hot-end to hit something solid enough to loosen the groove mount. Unless you fix that problem, the same thing will happen with the metal metal filament drive but instead of the easily-replaceable filament drive loosening, something else is going to have to give.
If the model is coming loose how is it giving enough resistance to wear out the filament drive ? I guess it could be attaching the whole model to the hot end, then when it moves sideways, it tries to push the model into the frame. Badness will still continue to happen with a strong filament drive - either the motors will skip, or maybe it'll bend the hotend itself ?

[jimc]

yeah i have to agree. i dont think there is anything wrong with a metal mount and drive but you should not be going through filament drives like that. we have all had it happen where the model comes loose but not on a regular basis. my printer runs constantly and i can count on one hand the # of times this has happened. you should get months and months out of a plastic drive and mount. im sure there are people still running their stock drive with printers over a year old.

[Rich]

Thanks guys. I think that I'll still have it (and the motor mount) machined. I'll get back to the group when something else breaks because of the aluminum parts.

Rich

[willnewton]

Typically the failure is on an overnight build when the model comes loose, apparently sticks up too far, and gets clobbered by the hot end repeatedly, resulting in a loose groove in the drive for the groove mount.

I would try to better understand what is happening to cause the hot-end to hit something solid enough to loosen the groove mount. Unless you fix that problem, the same thing will happen with the metal metal filament drive but instead of the easily-replaceable filament drive loosening, something else is going to have to give.

yeah i have to agree. i dont think there is anything wrong with a metal mount and drive but you should not be going through filament drives like that. we have all had it happen where the model comes loose but not on a regular basis.

Thanks guys. I think that I'll still have it (and the motor mount) machined.

Ummmm, yeah.

[Rich]

Ummmm, yeah. [/quote]

Maybe I should have been a bit more specific when describing the problem I have with ABS filament drive. The drive isn't literally breaking. It's the groove that holds the hot end in place that deforms, allowing the hot end to move. It would seem that this is a critical area that should have zero play. The machine and software can be dialed in perfectly, but if there's any play in the hot end/filament drive, it's for naught.

So, for you experts, is there a reason that in this critical area, the hot end isn't securely fastened to the filament drive? Was there another version of the drive that utilized the vertical holes on the bottom the filament drive to secure the hot end?

Judging by the number of posts related to this particular part, I don't think that I'm the only one with this problem.

[markb]

Have you tried printing this drive with close to 100% infill?
http://www.thingiverse.com/thing:267137
It works very well and as long as your cooling fan is working correctly.
You will get better results with this drive than the stock one.

[Rich]

Have you tried printing this drive with close to 100% infill?
http://www.thingiverse.com/thing:267137
It works very well and as long as your cooling fan is working correctly.
You will get better results with this drive than the stock one.

Yes, rsilvers' model is great, love the way the filament tube fits into the top. This is one that I'll try next, http://www.thingiverse.com/thing:320689 At least then I'll have a quicker build of the replacement.

[jimc]

rich, i have literally hundreds of hours of print time on any certain filament drive i have had and i have never had one loosen up on me. the stock ones though are running low infill and i could see this happening. i print all my drives at 80-100% infill. they are rock solid even after multiple removals on the hot end. 90% in abs and the piece is hard as a rock. i dont see it loosening up unless you have a real heat issue going on. i think you said this but you are absolutely positive your printing this in abs and not pla right?

[Rich]

Hey jimc

I'll give rsilvers' drive another shot over the weekend. I am using ABS for the drives with an 80% infill. They seem to work fine when printing PLA. The first time I printed ABS (using 245*) I melted the you-know-what out of the stock drive. I had Karen send 2 more and I trashed both. I finally figured out that my hot end runs hot, but last weekend I trashed another one at 235* On my machine 235* for ABS is fine, 245* is too hot! My M2 is a mid-December 2013 build.

On a slightly different note, what's the best way to calibrate an IR thermo gun? For my business, I have 8 different guns, from a cheapo Harbor Freight to multiple $100 Rayteks. They all vary at 350* (the temp that's important to me). Might the hot ends' thermistors have a "range"? I'd love to get a true reading of my ABS hot end. (I use separate filament drive/hot ends for each type of plastic that I print with)

Back to topic: what are the vertical holes on the bottom of the filament drive for?

THX, Rich