Filament Drive Tension Slipping?

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Gwhite
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Filament Drive Tension Slipping?

Post by Gwhite » Tue Mar 13, 2018 7:15 pm

My M2E is about 8 months old at this point, and I haven't been using it constantly. I typically run it off & on for several days & then go off for a week or two while I design up something new to print. Recently, I've been running it quite a bit more, and the print quality went to hell yesterday. I finally figured out that I didn't have enough filament drive tension, and tightened that up. It's printing just fine again.

I don't know if the screw slipped from vibration over time, or if my drive assembly is getting tired. I've marked the tension screw so I can see if it backs out over time, but I'm wondering if I need to print up a new drive while this one still works. There are a couple of improved designs on Thingiverse I may study first, and I've got a spool of black ePC in my Amazon cart...

Any idea if it's more likely to be a loose screw, or normal wear & tear on my drive? How often should I expect to have to replace the drive?

Thanks!

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zemlin
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Re: Filament Drive Tension Slipping?

Post by zemlin » Tue Mar 13, 2018 8:32 pm

I printed filament drives from ePC and I've seen just about zero creep, and I run in a 40C-50C heated enclosure.

Gwhite
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Re: Filament Drive Tension Slipping?

Post by Gwhite » Tue Mar 13, 2018 9:47 pm

I just finished a 6 hour print, and sometime around 5 & 1/2 hours, it looks like it slipped again, but the mark on the tension screw hadn't moved. I cranked up the tension a bit more & started another job. I wonder if the filament spool is jamming up occasionally. Every time I wander by now, I rotate the spool a hair to keep the tension to a minimum.

Gwhite
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Re: Filament Drive Tension Slipping?

Post by Gwhite » Tue Mar 13, 2018 10:39 pm

Well, that time it only went about a half an hour before it messed up big-time:
Filament Drive Problem 1.jpg
Filament Drive Problem 2.jpg
I restarted the job (again...) after tightening up the tension another 1/8th turn. It's doing just fine again, but I view the odds of getting a successful print as pretty low.

If this barfs again, I think I will try a different spool of filament. I'm using this Paramount 3D stuff to get the particular color, but I'm not impressed with their stuff. If I have to print it in blue eSun PLA+ to get them to come out OK, so be it.

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ednisley
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Re: Filament Drive Tension Slipping?

Post by ednisley » Tue Mar 13, 2018 11:42 pm

Gwhite wrote:it looks like it slipped again, but the mark on the tension screw hadn't moved
That can be due to filament diameter variations, because the screw sets the position of the idler pulley, rather than its force, which means the force drops dramatically as the filament gets narrower.

Some time ago, I installed a spring to eliminate the entire problem:
https://softsolder.com/2016/10/11/maker ... feed-gear/

Image

You'll need a much longer screw and a couple of washers, perhaps available from a nearby big-box home improvement store.

Gwhite
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Re: Filament Drive Tension Slipping?

Post by Gwhite » Wed Mar 14, 2018 12:29 am

I'll look into that. This Paramount 3d is the only stuff I've had issues with. sthone has a really nice design with dual springs: viewtopic.php?f=10&t=3283, and I plan on doing something similar.

In the meantime, it crashed again as soon as I stopped nudging the spool occasionally and had to go out & shovel snow. I've switched to a new spool of eSun PLA+, and half an hour into the job, so far so good...

Here's a couple photos of the teeth marks in the red Paramount filament after I increased the tension this morning. It certainly looks like it's got a good grip. Either the filament diameter is varying a lot, the spool is jamming up occasionally, or something weird is going on...
Filament Drive Marks.jpg

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ednisley
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Re: Filament Drive Tension Slipping?

Post by ednisley » Wed Mar 14, 2018 12:18 pm

Gwhite wrote:Either the filament diameter is varying a lot, the spool is jamming up occasionally, or something weird is going on...
As the saying goes, one careful measurement outweighs a thousand expert opinions ... [grin]

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willnewton
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Re: Filament Drive Tension Slipping?

Post by willnewton » Wed Mar 14, 2018 1:12 pm

Your tension looks fine, but Ed’s sprung screw looks like a great trick. I would probably look elsewhere for the cause.

I have NEVER had to babysit a filament roll the way you described. I have accidentally had the free end of the filament get itself under another loop on the roll and have trouble feeding though.

Since you have an M2e, you may want to check your Z axis screw. Got to keep it clean and free dropping to avoid possible issues.

You may want to try using another filament just to see if you can get the print to complete so at least you can narrow down the cause.

It is possible the filament may have some contaminant that is causing a partial or temporary clog.

I can’t remember who made the filament roll, but I have had one roll that I finally just gave up on and tossed in the trash. Problem solved!
I'm finally back to where I started two days ago!

A thread with some stuff in it I update every once in a while. viewtopic.php?f=8&t=9
See some of my stuff http://www.thingiverse.com/willnewton/about

Gwhite
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Re: Filament Drive Tension Slipping?

Post by Gwhite » Wed Mar 14, 2018 1:52 pm

Well, I swapped filament to a new roll of eSun PLA+, and the print came out just fine. I'll be running a couple more prints, but it certainly looks like the problem is with the filament. I've got to go on a trip in a few days & will have to wait until I get back to go over the offending spool to see if I can figure out what is going on.

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ednisley
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Re: Filament Drive Tension Slipping?

Post by ednisley » Wed Mar 14, 2018 3:49 pm

Gwhite wrote:a new roll of eSun PLA+
Tah-dum!

You'll probably measure inconsistent diameters along the Paramount filament.

I think a spring-loaded drive would cope with the variations, but I admit to some bias.

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