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Is there need for Mendel Extruder be flexible?

Posted by casainho 
Is there need for Mendel Extruder be flexible?
March 04, 2010 04:13PM
My prints are having a XY displacement, and that are running my actual prints :-(

The displacement is because there is small parts of extruded plastic as springs, and that springs later make force on my extruder noozle, making a displacement on it. I did attach the extruder PTFE with 4 screws, a bit like Makerbot extruder that uses 2 screws... but the problem is that excess of extruded filament, that makes springs...

I am not using FiveD firmware, so I do not have reverse option for extruder filament, which I am sure it would help to remove almost all springs...

Is anyone with this problem? XY displacement because of springs moving the extruder noozle?

If so, maybe the best idea would be to have a flexible extruder in a way that it would bend when get any springs on its way but soon it would go back to initial position - maybe using springs?


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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

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Re: Is there need for Mendel Extruder be flexible?
March 11, 2010 05:21PM
Ok, I went and did build it:


Since my prints have blobs and springs, sometimes the extruder noozle was going against them and causing problems, like changing the noozle position. I decided to try make a kind of flexible extruder, using springs.

It works perfectly! If there is something in the path of extruder, it simples goes over some side or go up, then the springs returns back the extruder to the same place, which means prints continues after as if nothing did happen :-)

I don't know if Mendel do need of such system, maybe Z axis is a kind of flexible... at least on my CNC it isn't.


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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
Re: Is there need for Mendel Extruder be flexible?
March 15, 2010 01:30PM
How is your extruder mounted to the CNC?

In the Mendel, the extruder is mounted between two steel rods. If the nozzle gets stuck on something, the rods will flex and the extruder will rotate around the X-axis. The result is that the nozzle moves up and clears the obstruction (if it is small).

I've been having trouble with my Darwin because the extruder hangs outside the two rods. If the nozzle gets stuck on something and the y-axis is moving in the negative direction, the rods still flex, but the extruder rotates down, forcing the nozzle into the obstruction and causing it to get more stuck.



Darwin clone, Gen 2 electronics, Arduino Duemilanove w/ AtMega328, 5D Firmware, Pinchwheel extruder
[www.codeerrors.com]
Re: Is there need for Mendel Extruder be flexible?
March 15, 2010 03:40PM
mccoyn Wrote:
-------------------------------------------------------
> How is your extruder mounted to the CNC?

It's fixed. Sorry, I can't explain with my poor english.


> In the Mendel, the extruder is mounted between two
> steel rods. If the nozzle gets stuck on
> something, the rods will flex and the extruder
> will rotate around the X-axis. The result is that
> the nozzle moves up and clears the obstruction (if
> it is small).
>
> I've been having trouble with my Darwin because
> the extruder hangs outside the two rods. If the
> nozzle gets stuck on something and the y-axis is
> moving in the negative direction, the rods still
> flex, but the extruder rotates down, forcing the
> nozzle into the obstruction and causing it to get
> more stuck.

Nice to know since I am building a Mendel.


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
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