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Skeinforge trouble with the first layer of object

Posted by khiraly 
Skeinforge trouble with the first layer of object
January 16, 2010 01:07PM
Hi!

I have trouble with skeinforge. I have beautiful prints except the first layer of the object.

Here is the .stl file, what I have printed: [sites.google.com]
Here is the generated gcode file: [sites.google.com]

Here are some photos about the problem (the first layer of the object delaminate from it):




The extruder motor is running at 40rpm, and the layer height is
0.43mm. See this blogpost for detail: [blog.arcol.hu]

Layer heights of the .gcode file:
first layer of the raft (thick one): 0.75
second layer of the raft (thin one): 1.25 (2. raft - 1. raft: 0.5)
first layer of the object: 1.72 (1-second raft: 0.47)
2. layer: 2.15 (2-1: 0.43)
3. layer: 2.58 (3-2: 0.43)
4. layer: 3.01 (4-3: 0.43)
5. layer: 3.44 (5-4: 0.43)


Here is my settings: [sites.google.com]
The zipped up skeinforge folder what Im using: [sites.google.com]
Also Im printing using "ABS WHITE 040 N6" profile.

So my question is, how could I change that the height of the object's first layer become to 0.43 from 0.47?

That is the only thing what I want to change. Other than that I have no problems with the prints. (ok the small layers has melting problem, but its an another story)

Any idea is most appreciated!

Best regards,
Laszlo

Here are some more photo about the teapot:



Re: Skeinforge trouble with the first layer of object
January 16, 2010 03:53PM
There was a bug with a version of skeinforge where the infill was inset too much. That is now fixed in the latest version at:
[members.axion.net]

and in the cached version at:
[fabmetheus.crsndoo.com]
Re: Skeinforge trouble with the first layer of object
January 16, 2010 06:27PM
Thanks for the help Enrique.

Looks like this new version forgot all my settings. The temperature is wrongly set in the .gcode file, it activates plugins which I have really bad experience with (speed, comb, cool, jitter). So it will take some days or weeks to set it again correctly.

And also it generates the .stl file a bit odd:

Re: Skeinforge trouble with the first layer of object
January 16, 2010 06:28PM
Enrique: Do you remember where it was the bug in the old version?
Maybe I could just fix it, and use the (tested) old version.

Best regards,
Laszlo
Re: Skeinforge trouble with the first layer of object
January 18, 2010 09:00AM
Ok, I changed the line 438 of raft.py from this:
self.operatingJump = self.extrusionTop - self.cornerLow.z + 0.5 * self.layerThickness + self.layerThickness * self.raftRepository.operatingNozzleLiftOverLayerThickness.value

to this:
self.operatingJump = self.extrusionTop - self.cornerLow.z + 0.5 * self.layerThickness + self.layerThickness * self.raftRepository.operatingNozzleLiftOverLayerThickness.value
self.operatingJump = self.operatingJump * 0.97674418604651159

I was not able to really spot the bug (other than that there are some evil math to determine the layer height). And I do believe the new version suffers from the very same bug. It has the same elevation:
0.75
1.25
1.72
2.15
2.58

I also imported the skeinforge source into a local git tree, because it is a really huge beast, so easier to track the changes.

I think I stick to this version from now on. It takes ages to set up a new version. So many parameters for so simple things like layer height.
I think I should be able to tell what layer height should use my machine....

Edited 1 time(s). Last edit at 01/18/2010 09:01AM by khiraly.
Re: Skeinforge trouble with the first layer of object
January 18, 2010 09:43AM
Ok, I modified 0.97674418604651159 to 0.97. Gives from 1.67 to 1.68 depending on the .stl. (still no idea why it depends on the .stl in the first place)
Re: Skeinforge trouble with the first layer of object
January 18, 2010 10:18AM
Turned out, it fixed the issue. Only a tiny part of one string detached from the object base.


Its dirty, but works.
Re: Skeinforge trouble with the first layer of object
January 18, 2010 10:53AM
It still doesn't look like the right amount of plastic / layer height to me. My objects come out with much flatter bottom, even when I was using a raft.

If you look at this object http://bp0.blogger.com/_QYCIPYPZ-pc/SIGbsn2zSpI/AAAAAAAABWU/bC7kYMpm-4w/s1600-h/brackets.JPG the base is much more tightly packed. The unsupported blind hole looks similar to the bottom of your teapot.

Edited 1 time(s). Last edit at 01/18/2010 10:54AM by nophead.


[www.hydraraptor.blogspot.com]
what is your first layer temp set at? i could be wrong but it looks like your temp is set low,'t change extruder feed rate as this will effect walls and bridging features. actually the entire thing looks like temp is set just a little low. have you tried a print out with a slightly higher temp? leave first layer temp where is is at to troubleshoot. raise temp slightly higher, or make the layer separation .45 instead of .5

still looks ok.

james
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