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Ultimaker2 Feeder System - Improvements and Ideas

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this is the kind of idea.. i wonder what the best way would be to transfer energy to three sides ?? or only one side is powered and the two other sides are not ?

gfdged.jpg

 

This concept you guys are tossing about is something like what I was trying to describe on the previous page, only I was consdiering two opposing wheels (MK8?) where one is driven and the other hinged. when the hinged idler is closed, it has a pinion that comes into mesh with the directly driven wheel.

Ian, Misumi caries a line of rubber and urethane drive rollers that may be suitable...

 

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the two back parts look good Robert... ? so not a complete loss I guess :smile:

 

You'd think so, wouldn't you? Sadly, no such luck. Corners were lifted. I printed a new set out over night and just finished test fitting. Still has a couple of issues but generally seems to work. The spring smashed the "core" part though when I stress tested it a bit. Snapped quite energetically and I'm now waiting for feeling to return to the side of my pointer finger :mrgreen:

 

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No one ever said progress is easy on the fingers. :mrgreen:

On a more serious note, I have a feeling we are straying from the original purpose here a bit. Although I like all the new drive mechanism ideas, I think we should focus on something proven, more in the line of Robert's idea. Designing and testing a completely new kind of filament transport takes time, and I'm sure the UM2 guys would love to print sooner than that. I've sent Harma a PM to see if we could get our hands on any solid models of the UM2 extruder, but haven't received a response, maybe Ian could do something about that? :)

 

 

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your right. we should stay focused and get this problem solved.

I know ultimaker themselves are also working on this problem at the moment. So between us and them we should have a much better solution in the next week or two.

About a tester sample from the extruder setup.. I will ask and dont see any problem. Only thing is Harma is away now and will be back on Monday. So she probably can only send out a sample of the case then...

TO ROBERT... robert can you add your solidworks in solidworks 2010 format anywhere on the net. Would like to examine your idea a little if i may...

Ian :-)

 

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Hope this works, never used Google drive before:

https://drive.google.com/folderview?id=0Bzb0IIx5JVctQXU3OW9xX3VQYmc&usp=sharing

And to those looking at the SW files, don't be too hard on me. For one, I'm self taught. Second, all the parts have been altered, re-drawn, drawn on top of and altered again so they're a mess :)

 

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Well I have a bit of a good news, bad news situation. Good news, seems to fit. Bad news, aint working. It's just grinding filament, not enough pressure so I need to re-adjust some things for more travel. And the case needs a bit of a strength adjustment for the mounting hole where the pressure arm thingy mounts (and by a bit, I mean a lot).

Really happy with the locking mechanism though. Just squeeze it shut and the arm falls down and locks things up.

extruderFirstMount

 

Don't feel like doing the whole tear down the new extruder, transfer parts to old extruder, put things back together again dance tonight though. It'll be a project for tomorrow.

 

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Well I have a bit of a good news, bad news situation. Good news, seems to fit. Bad news, aint working. It's just grinding filament, not enough pressure so I need to re-adjust some things for more travel. And the case needs a bit of a strength adjustment for the mounting hole where the pressure arm thingy mounts (and by a bit, I mean a lot).

Really happy with the locking mechanism though. Just squeeze it shut and the arm falls down and locks things up.

 

 

Don't feel like doing the whole tear down the new extruder, transfer parts to old extruder, put things back together again dance tonight though. It'll be a project for tomorrow.

 

It's quite close to the UM1 design. And it looks cool. I smell success... :D Congrats!

 

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I guess one would have to exchange the motor. A UM1 motor is too weak for extruder-direct-drive (means extruder with the knurled bolt on the motor axis). And it might transfer even more vibrations to the wood cage of the UM1 than the normal extruder design which would result in a higher noise level.

 

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That's not good... my new design allows for an ever so slightly larger amount of side panel interference. If there's a big variance in how much the side panels stick out that could be a problem... Oh well, no point in worrying about that until I know if I can get the beta version working in the first place.

 

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Robert, I read this post you made in the thread about UM2 extruder pulling force:

 

Because of the gear reduction of the old design which gives the original a lot more torque with a weaker motor and possibly not being current limited as much as the new one (speculation on my part). I've had the UM1 get a tangle on the spool, rip the whole spool off the holder and keep printing like nothing happened (scared the shit out of me though as I was in the other room when it happened). On the UM2 a bend in the filament means I can only print at 3-4mm3/s...

I don't have a 3d printer, I am planning on getting the UM2, with my only concern being these underextrusion issues (which I know may be hotend related).

If the UM1 design was so superior, why don't UM2 owners work on a way to make that design work on the UM2? I know I am speaking from a point of ignorance.

I suspect two things would change.

1) the current supplied by the controller is probably different.

Couldn't that be fixed with an inline microcontroller (and maybe even simpler circuitry?)

2) the extrusion distance per step is probably different.

Isn't this just a software setting somewhere? Something like extrusion distance per step?

It just seems to me like there was an existing solution at some point that got thrown out.

Again, my apologies for any ignorance I am showing about the software, electronics, and physical function of these extruders. I understand the UM2 one pretty well, but know VERY little about the UM1 one, partly because I think most users modified it from the original stock.

 

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This is just my own personal opinion based on my personal experience (which I'm sure differs from many people), so keep that in mind when reading.

I wouldn't say that the UM1 design is superior. It's different and being stronger isn't necessarily only good. It does bring with it other issues such as the famous "bowden pop" that plagued a lot of us back then. The thing is so strong that it wouldn't stop until the bowden got ripped out of the printing head and/or stripped the filament. On the other hand you could get away with going down in temperature and you could cheat a bit on bed leveling since it would just power on through. If you're a bit off on the new one and enough pressure builds up to make the motor skip there will be a brief moment of under extrusion which leaves a scar on the bottom surface (but the new platform is fantastic and you don't really have an excuse to not have a perfectly level bed).

The new design is a lot slimmer and neat, its reduced torque means that it will skip back rather than strip the filament or pop the bowden. Some argue that it offers better control since it's a direct drive rather than a geared drive. I have thought about transplanting a UM1 extruder but the compact design of the UM2 extruder is quite attractive and a lot more quiet.

It's a balance act and I think that with a slight increase in power the UM2 design will fit most people, even us "old timers" that are a bit set in our ways ;)

 

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Can anybody tell me the dimensions of the idler bearing in the UM2 extruder?

 

16 outer, 8 inner, 5 thick.

I've mounted my newest iteration but I just remembered that since the idler wheel has switched location I'm effectively running in reverse. I don't suppose there's a quick fix for that? I don't feel like physically moving the pins of the connector and I've actually never compiled a custom version of the firmware.

If a custom firmware is the easiest fix I'd really appreciate if someone could compile and upload a hex for me that matches what is in the machine except for the direction of the extruder (don't want to introduce any other variables into the test).

 

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Silly question (after about 30 hours with my UM2 and some feeder problems)...

To me, the main problem seems to be the fact that the feeder is really close by the case while the spool holder features a gap. The result is a filament feeder direction that is not straight, causing tension and therefore feeder problems.

Would it make sense to first fix this alignment by trying out a spool holder that is closer to the case? Illustration of the problem:

spoolholder

 

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