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Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 3:13 am
by sthone
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This is work in progress but I thought I'd share along the way.....
V4 Hinged 01.jpg
I started to have problem on one of my printers lately where it would just stop feeding. I tried adjusting the feed tension but even tightening it as tight as it could go I couldn't get a good bit on the filament. Taking the filament drive apart it looked like the springiness to it just wore out, plus the offset bolt in relation to the bearing always kind of bugged me as I figured it just wasn't getting even pressure on the bearing so I figured for shits and giggles I'd try to fix it.

V4 Hinged 02.jpg
I modified the original drive to add another bolt on the other side for even pressure and incorporated more of a hinge with a pin at the bottom to see if this would keep it from wearing out.

V4 Hinged 04.jpg
I've always been intrigued with the spring loading bearing on my Micron Extruder so I thought I'd give them I try on this one too.

V4 Hinged 05.jpg
Here is the initial prototype... I've changed a few things in the design since I printed this but it should work for a test.

V4 Hinged 06.jpg
So far I've just been experimenting with a few different springs to see what happens and so far it seems to work ok. For the first printing test I did remove the springs though and just used two of the standard stock bolts. I'm printing the revised version right now so I'll have to see what happens and go from there.

-Steve

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 3:28 am
by Jules
What's that original drive printed out of Steve? PETG?

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 4:18 am
by sthone
Yes PETG.. they been on there for almost nine months though.

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 4:28 am
by Jules
I've noticed that my little PETG spring under the bed has deformed a bit after several months of use too. (The PLA one went kaput rather quickly though, so it's still a better option.)

Bummer! :roll:

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 5:06 pm
by willnewton
Cool idea! You could add a filament tube holder to the top while you are at it.

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 6:21 pm
by Tim
sthone wrote:.This is work in progress but I thought I'd share along the way.....
It seems like a great idea. I see all sorts of other extruder designs making use of a spring-loaded tensioner, so I figured there must be something to it. But then I've never had any problem with the simple tensioner bolt used by MakerGear, and it involves less hardware, so in general there's less to go wrong.
Jules wrote:I've noticed that my little PETG spring under the bed has deformed a bit after several months of use too.
Every material deforms under enough force (unless it breaks first), but I've found PETg to be the most resilient. What kind of bed spring design are you using? I designed my spring based on a French curve, and while I'm not trained in mechanical engineering, I believe, based on my math and physics background, that this shape is evenly distributing the force along the length of the spring. After a half-year of use, it does not show any deformation that I can see (although the shape of it also makes it more difficult to see any deformation).

My filament clamp (http://www.thingiverse.com/thing:618173) was less of a filament clamp and more of a test of PETg deforming. The test prints I made of that model did deform slightly under repeated flexing, but didn't change much the force with which the clamps grip.

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 7:02 pm
by Jules
Tim wrote: Every material deforms under enough force (unless it breaks first), but I've found PETg to be the most resilient. What kind of bed spring design are you using? I designed my spring based on a French curve, and while I'm not trained in mechanical engineering, I believe, based on my math and physics background, that this shape is evenly distributing the force along the length of the spring. After a half-year of use, it does not show any deformation that I can see (although the shape of it also makes it more difficult to see any deformation).

My filament clamp (http://www.thingiverse.com/thing:618173) was less of a filament clamp and more of a test of PETg deforming. The test prints I made of that model did deform slightly under repeated flexing, but didn't change much the force with which the clamps grip.
I'm using the Breylon Z-Axis Return Spring. And it still works, I've just noticed that the top arm of the "Z" has gotten a bit flattened now. The rest of the zig-zags have stayed put. (I think i'd flagged your design long ago to try as well, then just got distracted.......I need to print that one out and give it a try. The arch in a French curve is the strongest shape to resist deformation under load.)

Nope - must have forgotten to flag it, although I do remember seeing it once. I'll go do that now. Definitely worth a try. Muchas gracias! :D

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Thu Jan 21, 2016 8:49 pm
by sthone
Tim wrote:It seems like a great idea. I see all sorts of other extruder designs making use of a spring-loaded tensioner, so I figured there must be something to it. But then I've never had any problem with the simple tensioner bolt used by MakerGear, and it involves less hardware, so in general there's less to go wrong.
Yeah the original design is pretty simple and I usually subscribe to the KISS principle this was just something I'd thought I'd try experimenting with. ( it's just my nature. :D ) In theory (least how I see it) the spring design should account for any variance in the thickness of the filament and maybe keep the gear from stripping it out... but in reality if it's stripping out there is probably some other root problem to begin with. The springs where just an after thought the main fix I was going for was the hinge part and the added tension bolt.
willnewton wrote:Cool idea! You could add a filament tube holder to the top while you are at it.
I might have to go back and add that feature on, it would make it a lot easier when trying to change filaments on the fly too. I always have a hell of a time sticking the new filament in that little hole with the head jumping around. A holder extension with a funneled bottom would probably make it pretty simple to do.

-Steve

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Fri Jan 22, 2016 12:06 am
by jimc
for you guys printing extruder drive parts, i cant recommend enough printing them in epc. kinda sucks it just comes in the natural color but man what a difference. rock hard, high temp and best of all is flame retardant so if you ever get into a runaway temp problem you'll have a fighting chance of not firing up your whole house. i only have one printer left to convert over to epc. because its so rigid and high temp its the best thing going for printer parts.

Re: Modified (Hinged) V4 Single Filament Drive

Posted: Fri Jan 22, 2016 1:24 am
by Jules
jimc wrote:for you guys printing extruder drive parts, i cant recommend enough printing them in epc. kinda sucks it just comes in the natural color but man what a difference. rock hard, high temp and best of all is flame retardant so if you ever get into a runaway temp problem you'll have a fighting chance of not firing up your whole house. i only have one printer left to convert over to epc. because its so rigid and high temp its the best thing going for printer parts.
Can I assume if you haven't painted it, that nothing will stick? :(
(eSun needs to get some more colors then, I like my sleek black baby, and want to keep her that way :P )