Belt Drive Extruders?

Has anyone here played around with any of the belt driven extruder designs (similar to http://www.thingiverse.com/thing:84678)? If so, any thoughts? Do they work as well or better as a herringbone gear setup? any surprises?

I’m thinking a belt drive flexystruder would be an interesting project. the motor bracket and pulley set should weigh less than the standard Wade’s bracket and gear slightly. Extruder inconsistency on very small parts seems to be an area my machine still needs work in, so if it is indeed a more accurate method i’m all for trying one, but I would like to know if anyone else has had a good or bad experiance with them before I give it a shot.

Mmmmmm… I like it.

Let us know if you end up trying this out, I’ll be really interested to see how it works as well.

I placed an order for the 2 pulleys and a belt this afternoon. I’ll render a 0.3 belt variant this weekend and then try it out whenever the belts get here. Should be a pretty simple design change. The big question is how to handle the belt tensioning. Slide holes and just bolt in place for tension, or actually include a threaded precision tensioning mechanism?

I probably need to order some more hobbed bolts and nema motors so I can try a few variants out without having to take things completely apart.

edit: version 1 of it is in your filliament forum thread for the flexystruder now. I’ll probably make a couple minor tweaks to the tensioner when I get time, but it should, in theory, maybe work?

one of the big benefits of the gear drive is the ability to print the gears, instead of buy them.
Belts are usually quieter…but that is not really a problem.

you should be able to print your own pulleys…but the belts would be tougher. even if you did print them out of flexible material, they may stretch over time.

Definitly. I still haven’t got the dang belt parts yet. The only reason i’m looking at it as an option is for the potential for greater retraction and extrude accuracy. The gears have a very small, but measurable backlash built into them, which increases over time as the surfaces wear. The theory is that the pulley eliminates that, and also reduces rotating mass without reducing applied force allowing for a slightly more accurate extruder. Thats the one area of my prints that tends to need work at the moment, so anything I can do to make my extrusion more accurate and eliminate the occasional “microblob” is a worthwhile upgrade. Thats assuming it works at all. We’ll find out soon hopefully.

have you calculated what that small amount of backlash in the gears translates into at the filament…it is VERY small.

moisture in the filament will cause WAY more blobs than a small amount of backlash.

Yeah, and the filliament already lives in a pike of silicone dessicant pellets salvaged from hard drive shipments anyways. I agree it will probably be really minor, but the reduced rotating mass on the extruder and the loveer theoretical overall weight make it attractive as an option too. Besides, I like tinkering with the machine to see if I can make it even a little better.

So whats the verdict on the a belt driven extruder?

@theycallmejohn
Its moved to this thread
https://forum.lulzbot.com/t/belt-driven-extruder/1398/1

It works pretty well actually. I’ve never really had a problem with gear wear or skipping or anything so I wasn’t looking at it for that. It’s lighter, and a bit more responsive on very small things than the gears are. It is a bit of a pain to set up though.

I’ve actually been playing with dual hobbed bolt geared designs recently, but the ROV project put some of that on the back burner.

I saw that thread, I thought they were just addressing issues. I went back to Piercets original discussion to see his verdict. :smiley: