M2 nightmare with soft filiment

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airscapes
Posts: 161
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 nightmare with soft filiment

Post by airscapes » Wed Jun 20, 2018 4:26 pm

Gwhite wrote:
Wed Jun 20, 2018 11:17 am
Also, it's only going to be ~ 1 mm thick at the bottom of the groove. The rest of it will be at least a half a mm thicker.
If the original bearing has a Diameter of 16mm and this replacement is 14mm, then 1mm thickness band all the way around the bearing will make the diameter 16mm, right?
Which leave very little room for groove . Unless there is clearance in the original house for a diameter greater than 16mm?

Gwhite
Posts: 187
Joined: Tue Jul 11, 2017 3:38 pm

Re: M2 nightmare with soft filiment

Post by Gwhite » Thu Jun 21, 2018 1:03 pm

I have a dead housing with the factory bearing in it. It looks like there is about 3/4 of a mm clearance of each side (~ 17.5 mm ID). So, you could make the OD of the sleeve 17 mm, and the bottom of the groove 16 mm (1/2 mm deep). You might have to shave down the OD a tiny bit from that to fit in an original housing, but that's where I was going to start. I think you definitely need to radius the outer edges to clear the inside better.

If I get a chance, I will see if I can make up a drawing of what I have in mind. Turning the sleeve shouldn't be a big deal, but I still need to grind a form tool for the groove. That and cutting the ID for a proper press fit need to be done carefully, and I've got too many distractions this week.

I was eventually going to make a dual spring housing anyway, and could make the bearing cavity slightly larger. However, even a shallow groove with the factory housing should help a lot to keep the flexible filament from wandering IF you don't try to push it through the hot end too fast.

airscapes
Posts: 161
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 nightmare with soft filiment

Post by airscapes » Thu Jun 21, 2018 2:04 pm

Gwhite wrote:
Thu Jun 21, 2018 1:03 pm
I have a dead housing with the factory bearing in it. It looks like there is about 3/4 of a mm clearance of each side (~ 17.5 mm ID). So, you could make the OD of the sleeve 17 mm, and the bottom of the groove 16 mm (1/2 mm deep). You might have to shave down the OD a tiny bit from that to fit in an original housing, but that's where I was going to start. I think you definitely need to radius the outer edges to clear the inside better.

If I get a chance, I will see if I can make up a drawing of what I have in mind. Turning the sleeve shouldn't be a big deal, but I still need to grind a form tool for the groove. That and cutting the ID for a proper press fit need to be done carefully, and I've got too many distractions this week.

I was eventually going to make a dual spring housing anyway, and could make the bearing cavity slightly larger. However, even a shallow groove with the factory housing should help a lot to keep the flexible filament from wandering IF you don't try to push it through the hot end too fast.
Is there a reason that a 3d Printed sleeve would not work rather than metal.. Nylon/EPA would should be more than tough enough to work (if I could get it to run in the oem drive :D )
sthone is going to try and find the cad files for his duel spring drive so I can modify for sleeved bearing. I plan on doing the hinged dual spring housing and see if that takes care of the problem before moving to sleeving the bearing

Gwhite
Posts: 187
Joined: Tue Jul 11, 2017 3:38 pm

Re: M2 nightmare with soft filiment

Post by Gwhite » Fri Jun 22, 2018 1:18 am

A printed sleeve is going to be very difficult to make precise enough to get a good press fit. You also don't want to introduce ANY diameter variations that will make it feed unevenly. It might work OK for soft filament, but if you want it to work with more rigid material, I suspect it may wear quickly.

airscapes
Posts: 161
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 nightmare with soft filiment

Post by airscapes » Fri Jun 22, 2018 4:01 am

Gwhite wrote:
Fri Jun 22, 2018 1:18 am
A printed sleeve is going to be very difficult to make precise enough to get a good press fit. You also don't want to introduce ANY diameter variations that will make it feed unevenly. It might work OK for soft filament, but if you want it to work with more rigid material, I suspect it may wear quickly.
Makes sense! I guess If I have to go that route, I could print it as a prototype for my machinist friend to make me something out of metal. It would also help in the housing alterations. I am kind of hoping the hinged spring loaded drive does the trick!

Gwhite
Posts: 187
Joined: Tue Jul 11, 2017 3:38 pm

Re: M2 nightmare with soft filiment

Post by Gwhite » Thu Jun 28, 2018 3:05 am

I've attached a drawing of what I have in mind. The press fit over the bearing is tricky. If it's too tight, you may snap the sleeve. If it's too loose, it may expand enough when hot to begin slipping. I made a guess as to what would work, but I can't easily measure stuff that fine anyway, so it's mostly going to be trial & error.
Grooved Extruder Bearing Sleeve.gif

airscapes
Posts: 161
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 nightmare with soft filiment

Post by airscapes » Thu Jun 28, 2018 3:46 am

Hey this is great! And I have that bearing sitting in the shipping bag on my desk, have not opened it yet.
I also have the files for the dual spring drive and am using it as originally designed So when I get a chance I will alter it to make room for a bigger bearing as I think if I make the sleeve out of EPA it will need to be bigger than if it was made of metal.. but maybe not! Will keep you posted!

airscapes
Posts: 161
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 nightmare with soft filiment

Post by airscapes » Thu Jun 28, 2018 11:14 pm

I modeled your drawing and made a few size changes and the bed is heating to print in PLA just to be able to hold it and put filament in the grove etc.. I expanded the grove to 1.75 and .875 deep an overall diameter of 16.5 to compensate for most of the groove depth so the filament is still close enough to the drive gear.. I think I needed to do that.. will know more when I can touch it and slide it in the OME house for fit..

3d image bearing.JPG
sleeve drawing1.JPG
bearing sleeve.stl
(2.05 MiB) Downloaded 3 times

airscapes
Posts: 161
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 nightmare with soft filiment

Post by airscapes » Thu Jun 28, 2018 11:57 pm

First print in PLA done and fits great. I did not use support and it looks like the grove is not symmetrical and thicker on the bottom half. Next up will be to "Try" and print it in PETG with the currently installed .25 nozzle.. It fits in the OEM housing but I dont have an extr shaft and nut. It lines up whit the hole with a little to spare but I don't think it will move close enough to the drive gear to get a good bite without hitting the houseing on the gear side. I would guess a file could fix that. First a reprint in PETG and then maybe EPA? EPA is more flexible but also very stable when it come to temperature from what I can tell.
20180628_184737.jpg
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airscapes
Posts: 161
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 nightmare with soft filiment

Post by airscapes » Fri Jun 29, 2018 1:57 am

PETG with lots of support turned out fairly nice.. will have to wait till tomorrow night to try it out.
20180628_204232.jpg
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