PolyBox issues Da Clumsy Noob solved to stop grinding

[kmanstudios 1,043]

Frankly, this may seem to be common sense to the experienced people, but for da Clumsy Noob, I had to suss it out.

 

This is my current setup with two polyboxes feeding my UM3Xs.

 

It has proven to be quite efficient once I gots me head out me arse.

 

 

Figures A1 and B1 show the proper way to do it. Make the filament's natural spool curve help stop binding.

 

Figures A2 and B2 show how it can twist off in another direction and it will fight the curvature of the bowden tubes and increased the likely hood of binding and grinding. Then you get a cascade of issues.

 

Figures A3 and B3 show how loading the filament from the wrong side can make it worse as it compounds the corkscrew action. In this case, since I am feeding below the printer, I found it best to feed from the bottom of the spool.

 

The filament is never in the feeder long enough to make it straighten out or combat shape memory of these materials. Some are worse than others.

 

Whether feeding from the bottom as I am now or the side or behind, make sure your filament does not corkscrew or curve opposite of the Bowden Tube. Following the curvature greatly reduces chances of friction in the Bowden Tube.

 

I did burn some plastic and other materials printing over the weekend getting this to work smoothly as I had to solve one issue after another. For instance, as I moved the materials and setup the new arrangement, one of my materials got the dreaded cross wiring where it bound on itself. So, working through issues like that one at a time, I got the above working and all my profiles work splendidly now.

So, in short:

 

Figure A1 and B1 good.

Figure A2 and B2 bad.

Figure A3 and B3 very bad.

Edited January 30, 2018 by kmanstudios
Added information

[ChrisRiddell 13]

What's the difference from A1/B1 to A2/B2 I can't see it?

 

 

Because I myself don't have room to run it under the printer I found this to be the only way to get the polybox to work, I wanted it to be beside the printer so I could read the display but it can't be done as it puts to much pressure on the filament turning to the right then going up, even with hanging spool holder inside.

[kmanstudios 1,043]

Figures A1 and B1 show that feeding the filament curvature in the direction of the curvature of the bowden tube helps it feed because it does not want to bend against the bowden tube.

 

Figures A2 and B2 demonstrate that if the curvature is not aligned with the bowden tube, it will tend to bend against the curve of the bowden tube and increase friction.

 

Sorry that I did not make that clear, and may still not have. I have had about 2 hours of sleep since yesterday and the ol' clockworks in this dusty belfry may be freezing up a bit. I do hope that this is more clear. If not, please ask again. I aim to help and if I am not clear, then it ain't happening.

[gr5 1,276]

To make this clearer - the A2 area should show the yellow filament coming from the TOP of the spool.

[kmanstudios 1,043]

10 minutes ago, gr5 said:

To make this clearer - the A2 area should show the yellow filament coming from the TOP of the spool.

I put it on the bottom because that is the way it would feed, at least by my thinking, but it can still get twisted. That is what took me so long to figure out what happened. I have always fed from the bottom as the illustration shows, but the coiling can be a problem if one is not careful when pulling it out or it will corkscrew.

 

I think that maybe adding a (3) series to the mix would be good to illustrate your point. If anything, just to show that it would be wrong to load it that way for a feed going up like this.

[gr5 1,276]

Oh - maybe now I get it.  So A2 filament - as it is drawn out - has a half twist such that it tends to want to curve the wrong way.

[gr5 1,276]

If I finally understand then an arrow that points to the filament coming out of A2 and says "half twist"?

[gr5 1,276]

By the way, PLA doesn't really need all this but PVA and Nylon need it so bad I like to limit the exposure to air to just a few inches.  I'll have to photograph my setup the next time I do Nylon.

[kmanstudios 1,043]

hahahahaha, yeah, it was PLA that was grinding on me like you would not believe. And, yeah, I think adding half twist to make the information more clear is a great idea.

 

As far as exposing to air, I run bowden tubes from the boxes to the feeders for just that purpose. I do not worry about it on PLA, which is my prime printing material, but PC, PVA and Nylon, definitely. Fortunately the Polyboxes came with nice bowden tubes for that purpose.

[kmanstudios 1,043]

I added information and modified th3 graphic based on suggestions by @gr5. Hopefully, I did not bollix it up.

[yellowshark 148]

OK I get it, good idea and a nice setup you have there. Probably because of that reason and that I cannot locate the filament underneath or behind (using your method) the printer I nearly always buy loose filament because it does not have as a tight a curvature as spooled filament and so takes the 90 degree turn into the Bowden tube without giving problems.

[kmanstudios 1,043]

I have used loose filament and it has always gotten tangled on itself. Very frustrating when it binds itself into a knot at the feeder. I do know it must be me that is making a mistake as so many others say it is a good way to go, but I have not figured it out.

[yellowshark 148]

I know what you mean; I limit myself to 50m lengths and always totally unwind, carefully making sure there is not a twist in it and then wind it up again using big loops before laying it on the floor.

[kmanstudios 1,043]

@ChrisRiddell, I just saw this as possible solution to your issues if you can put a shelf above your machine.

 

 

And, it should be easy to mod your polybox to do this and still keep the dry element to it. You would just have to print a couple of mounting brackets for the existing bearings and shaft that are in the Polybox and turn the hygrometer over so it would be easy to read. Just flip the Polybox over, it already has the holes you would need.

 

@yellowshark, I have no idea how you still keep it straight. I would unroll, roll into big loops like a rope, etc. Still tangled up something fierce.

 

[ChrisRiddell 13]

Going from above will not work on the Ultimaker as the filament enters the feeder from the bottom meaning the plastic would need to make a U shape once it gets to the feeder.

[kmanstudios 1,043]

Just now, ChrisRiddell said:

Going from above will not work on the Ultimaker as the filament enters the feeder from the bottom meaning the plastic would need to make a U shape once it gets to the feeder.

You are right.....duuurrrhhhhh....sorry. I got a bit carried away with the idea without really thinking it through.

 

You could always turn the printer over...LOL

[geert_2 357]

11 hours ago, ChrisRiddell said:

Going from above will not work on the Ultimaker as the filament enters the feeder from the bottom meaning the plastic would need to make a U shape once it gets to the feeder.

Unless maybe you would guide the tube into a smooth U-turn with an empty spool or something similar? But this would require a very long bowden tube, which is also not good...

 

I was considering PolyBoxes, but now that I see how big they are, almost the size of an UM itself, I don't think I have enough room in my fume extraction cabinet.

 

[kmanstudios 1,043]

7 minutes ago, geert_2 said:

Unless maybe you would guide the tube into a smooth U-turn with an empty spool or something similar? But this would require a very long bowden tube, which is also not good...

 

I was considering PolyBoxes, but now that I see how big they are, almost the size of an UM itself, I don't think I have enough room in my fume extraction cabinet.

 

I can definitely see the size as an issue. Most of that is for the 'wings' on either side of the filament that are made to house the desiccant.  But the basic design is sound and could be easily modded to make one from scratch. There are a gazillion designs out there, but most of them are actually larger.

 

I think a modded version that is more vertical (desiccant underneath spools) with tighter borders on the spools would be helpful for a lot of people.

 

It was the size that made me think about getting the end tables and putting the equipment in the arrangement I did.

[GFlow 0]

For this to work does the filament need to exit the holes in the top of the polybox?  Or could you use holes drilled into the black section on the bottom?

[kmanstudios 1,043]

That would depend on the direction of feed you are using. The illustration here revolves directly around my current setup. If you are feeding from behind or side I would say bottom holes. Basically the route that has the least amount of resistance. Remember that you are going through another bowden tube and you may need to crank the tension up a bit to accommodate the added friction. And, the more curve, the more friction.

[GFlow 0]

So I have my poly box setup like this and for some reason the PVA always wants to twist on me.  I even swapped the side it runs from, but whenever it feeds it kicks to the side. It seems as if the PVA is more bound up than then nylon I am using.  My old setup may have been twisting it a bit and I guess this could be the reason for it wanting to twist now.  Would it be worthwhile heating up the PVA to try to de-stress it?

 

Also has anyone thought of printing some guides for the bearings on the polybox?  So even if it does want to kick to the side it can't?

 

Thanks in advance

[kmanstudios 1,043]

Mine kicks to the side, but never tangles. However, there are a lot of stand options on Thingiverse that would fit nicely inside the Polybox.

[Torgeir 96]

Hi Kmanstudios,

 

This is what I tried to explain/said here for a looong, long time, but to "dead" ears, -I'll think..

I'm running the track line inside the loop and use less retraction due to less friction. I'd love to show some numbers about this, -but loose interest., ?...

I can print things at quite a good quality due to those small modifications I've done to my printer. And it is still a plain "UM2" configuration printer, using the original setup -but have some small adjustment to behave proper..

 

What you show here should be corrected long time ago. There is a few of comments about this issue in this forum.

 

Keeps up the good works.

 

Thanks

 

Regards

 

Torgeir.

 

[kmanstudios 1,043]

Unfortunately, I am not familiar with any printers before the UM3(E) series. They are completely different animals.

 

I am hoping someone here like maybe @gr5 or @fbrc8-erin can help you. They are much more knowledgeable than I on these matters. Sorry. :(

[gr5 1,276]

The feeder on the UM2 plus is identical to the left feeder on the UM3.  Same height.  Same feeder parts.  Same feeder.  Basically I don't like the looks of that hole inthe upper *rear* of that polylbox.  I guess if the filament came over the top of the spool and went straight out.  Better to have the hole near the same corner but on the top face I think - maybe drill a small hole and transfer the o-ring/gasket to the new hole and plug the old hole?  Not sure.  

 

I am cheap so I just use a gallon sized zip lock for nylon and pva and zip the bag mostly up except for a few cm to let the filament out.  I place all of that either on the table behind the printer or on the floor behind and below the printer.

 

Nylon is wonderful in it's flexibility.  Very few filaments are as flexible as nylon so this issue with pva will happen with pla and ngen and pet and cpe and pc.