Z-Axis Layer Problem
Posted by Robots-Dreams
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Z-Axis Layer Problem August 20, 2012 11:43AM |
I'm running into a strange problem with layers along the z-axis.
If a part is relatively short - say under 30 mm tall, then the part surface is very smooth and the layers are almost indistinguishable. But, when I print a tall part, the taller the part the more distinguishable the layers become.
A good (or bad) example is this Bag Handle part:
It's 82 mm tall. I laid it down to photograph with Z0 to the right of the part in the image and the top of the part to the left. The first 30 mm along the z-axis are quite smooth:
As you move up along the z-axis the layers become more and more pronounced. Near the very top of the part - say 70mm to 82 mm - they are so noticeable that they feel like teeth on a file:
This part was printed with 150 micron layers and sliced with Slic3r 0.7.2. I've examined the gcode in Replieter and can't find any differences that would account for this problem. I've run into the same problem with other tall parts that I've printed. So I'm wondering if it is a mechanical adjustment/alignment issue with my machine.
----------------
Lem Fugitt
3D Printing Dreams
Robots Dreams
"The map is not the territory."
If a part is relatively short - say under 30 mm tall, then the part surface is very smooth and the layers are almost indistinguishable. But, when I print a tall part, the taller the part the more distinguishable the layers become.
A good (or bad) example is this Bag Handle part:
It's 82 mm tall. I laid it down to photograph with Z0 to the right of the part in the image and the top of the part to the left. The first 30 mm along the z-axis are quite smooth:
As you move up along the z-axis the layers become more and more pronounced. Near the very top of the part - say 70mm to 82 mm - they are so noticeable that they feel like teeth on a file:
This part was printed with 150 micron layers and sliced with Slic3r 0.7.2. I've examined the gcode in Replieter and can't find any differences that would account for this problem. I've run into the same problem with other tall parts that I've printed. So I'm wondering if it is a mechanical adjustment/alignment issue with my machine.
----------------
Lem Fugitt
3D Printing Dreams
Robots Dreams
"The map is not the territory."
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Re: Z-Axis Layer Problem August 20, 2012 09:43PM |
Sublime Wrote:
-------------------------------------------------------
> Yeah I found it the most noticeable on the Maker
> beam. You could see it get worse as the print got
> higher and some would even come off the bed as
> the force push and pulled it around near the top.
The Maker beam might be a good test/calibration part to experiment with for this. Which one of the maker beam STL files do you use?
Besides the obvious surface finish aspect, one of the reasons I'm quite interested in this is that I want to build a larger bed Tantillus. Most of the parts I design/print will fit within the 100x100x100 envelope, but there are exceptions, like smartphone/iPhone cases, and some robot frames. Some of them I could lay down to print, but a few will need to be printed upright.
> Its hard to say, it should lower the viscosity but
> could also start to crystallize the plastic if you
> raise it too much.
I've seen that on some parts, and backed off. Right now I'm printing consistently at 180 degrees with 150 micron layers without delamination issues.
> If you want a setting that will
> reduce I would say lower the print speed. But
> instead of lowering the whole prints speed just
> reduce it near the top by adding M220 S50 to the
> gcode file where it starts to show the problem.
> You could een lower it gradually with M220 S90
> and then a M220 S80 and Then M220 S70 etc etc etc
> (S70 = 70% the speed of slic3rs set speed).
Excellent!
Assuming that works, then I can write a simple post-processor that scans the gcode, finds the Z moves, and inserts speed commands based on the layer height.
Thanks!
Edited 2 time(s). Last edit at 08/21/2012 12:09AM by Robots-Dreams.
----------------
Lem Fugitt
3D Printing Dreams
Robots Dreams
"The map is not the territory."
-------------------------------------------------------
> Yeah I found it the most noticeable on the Maker
> beam. You could see it get worse as the print got
> higher and some would even come off the bed as
> the force push and pulled it around near the top.
The Maker beam might be a good test/calibration part to experiment with for this. Which one of the maker beam STL files do you use?
Besides the obvious surface finish aspect, one of the reasons I'm quite interested in this is that I want to build a larger bed Tantillus. Most of the parts I design/print will fit within the 100x100x100 envelope, but there are exceptions, like smartphone/iPhone cases, and some robot frames. Some of them I could lay down to print, but a few will need to be printed upright.
> Its hard to say, it should lower the viscosity but
> could also start to crystallize the plastic if you
> raise it too much.
I've seen that on some parts, and backed off. Right now I'm printing consistently at 180 degrees with 150 micron layers without delamination issues.
> If you want a setting that will
> reduce I would say lower the print speed. But
> instead of lowering the whole prints speed just
> reduce it near the top by adding M220 S50 to the
> gcode file where it starts to show the problem.
> You could een lower it gradually with M220 S90
> and then a M220 S80 and Then M220 S70 etc etc etc
> (S70 = 70% the speed of slic3rs set speed).
Excellent!
Assuming that works, then I can write a simple post-processor that scans the gcode, finds the Z moves, and inserts speed commands based on the layer height.
Thanks!
Edited 2 time(s). Last edit at 08/21/2012 12:09AM by Robots-Dreams.
----------------
Lem Fugitt
3D Printing Dreams
Robots Dreams
"The map is not the territory."
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