cut into part on y finish

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cut into part on y finish

Postby RichC » Mon Feb 29, 2016 11:43 am

Hi,
I've been using Meshcam for years and have not had any issues but u have a part where the tool path moves down into the part instead of up the edge of it. this is where the cutter meets the end of a vertical surface in Y-axis finishing, not seen this before or since, but I have a hole in my part :? , which is easily fixed as it's just blue Styrofoam ;) .

using latest Meshcam release, v6 build 27.
my own post, modified for Kflop, original was EMC2,

it seems I am unable to add the G-code file or part as the maximum file size is 1MB, I can email it.

Thanks,

Rich.
Attachments
meshcam error.jpg
meshcam error.jpg (183 KiB) Viewed 1280 times
RichC
 
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Re: cut into part on y finish

Postby Randy » Mon Feb 29, 2016 6:31 pm

Rich, that does seem to be a bug on the last two builds of MC. There is a discussion on the Carbide3D forum at http://community.carbide3d.com/t/meshca ... ndows/1237

This forum won't allow attaching pdf's, and is too smart to allow a pdf renamed with jpg extension, so here is the contents of the report I sent Rob:

I can’t figure out what is causing the gouging. I created some solids the same size as Mark’s bracket—1x1.25x1, with a .25” thick base and a .75” tall boss.
The first solid has a convex wall extending to the edge of the base and no edge fillet.
gougereport_Page_1_Image_0001.png
gougereport_Page_1_Image_0001.png (196.82 KiB) Viewed 1274 times

No gouging.
gougereport_Page_1_Image_0002.png
gougereport_Page_1_Image_0002.png (84.98 KiB) Viewed 1274 times

The second solid has a concave wall extending to the edge of the base and no edge fillet.
gougereport_Page_2_Image_0001.png
gougereport_Page_2_Image_0001.png (165.78 KiB) Viewed 1274 times

No gouging
gougereport_Page_2_Image_0002.png
gougereport_Page_2_Image_0002.png (71.94 KiB) Viewed 1274 times

The third solid has a convex boss that doesn’t reach the edge of the base.
gougereport_Page_3_Image_0001.png
gougereport_Page_3_Image_0001.png (227.74 KiB) Viewed 1274 times

No gouging on either face
gougereport_Page_3_Image_0002.png
gougereport_Page_3_Image_0002.png (87.02 KiB) Viewed 1274 times

gougereport_Page_4_Image_0001.png
gougereport_Page_4_Image_0001.png (84.38 KiB) Viewed 1274 times

The next solid has a convex boss that doesn’t reach the edge of the base
gougereport_Page_4_Image_0002.png
gougereport_Page_4_Image_0002.png (243.03 KiB) Viewed 1274 times

No gouging on either face again
gougereport_Page_5_Image_0001.png
gougereport_Page_5_Image_0001.png (95.77 KiB) Viewed 1274 times

gougereport_Page_5_Image_0002.png
gougereport_Page_5_Image_0002.png (73.67 KiB) Viewed 1274 times

I went back to the first solid and added a .05” fillet where the convex wall meets the base edge.
gougereport_Page_6_Image_0001.png
gougereport_Page_6_Image_0001.png (189.84 KiB) Viewed 1274 times

No gouging
gougereport_Page_6_Image_0002.png
gougereport_Page_6_Image_0002.png (73.27 KiB) Viewed 1274 times

Same result when I increased the fillet to .10”—no gouging.

Mark’s bracket solid
gougereport_Page_7_Image_0001.png
gougereport_Page_7_Image_0001.png (137.91 KiB) Viewed 1274 times

Does gouge
gougereport_Page_7_Image_0002.png
gougereport_Page_7_Image_0002.png (103.1 KiB) Viewed 1274 times

I imported Mark’s STL into SolidWorks and saved as a solid (input check passes—no gaps or other errors) and re-exported as STL and it still gouges. That eliminates the possibility of a funky STL export in the original file.
I exported my original solid in a coarser STL that has face sizes closer to Mark’s STL, and it still doesn’t gouge.
gougereport_Page_8_Image_0001.png
gougereport_Page_8_Image_0001.png (103.16 KiB) Viewed 1274 times

I can’t figure out what is causing Mark’s bracket STL to gouge. It only gouges on the junction between the flat base and the vertical wall but I can’t duplicate it with a fresh model.


The only thing I "know" is that the problem seems to be at the base of a vertical wall, "in some cases". I haven't found a way to repeatably trigger the bug.

What software are you using to generate the STL, Rich?

Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
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Re: cut into part on y finish

Postby RichC » Tue Mar 01, 2016 3:13 pm

Randy,
I am using Solidworks, the funny thing is I had 2 parts in that setup, mirrored halves of a hollow part, I was using the machining regions to generate the toolpaths separately but in one block to save setup time, it only did it on one half. the other half was fine.

Rich.
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Re: cut into part on y finish

Postby RichC » Mon Mar 07, 2016 3:37 pm

well I've done it again, this time I have saved the setup exactly as it does it, it seems to be repeatable with the saved setup and tool settings which are attached, the error is on the bottom of the part. and this time it is both the roughing and the waterline which are cutting into the part.

Rich.
Attachments
meshcam error part.jpg
meshcam error part.jpg (142.83 KiB) Viewed 1216 times
meshcam error waterline.jpg
meshcam error waterline.jpg (123.94 KiB) Viewed 1216 times
meshcam roughing only.jpg
meshcam roughing only.jpg (146.93 KiB) Viewed 1216 times
settings.zip
(626 Bytes) Downloaded 67 times
mid fus centre left setup.zip
(296.96 KiB) Downloaded 78 times
RichC
 
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Re: cut into part on y finish

Postby FredB » Tue Sep 06, 2016 3:33 am

Try increasing the tolerance (global parameters). I've seen this happen if I go super accurate. 0.075mm seems to work well (about 0.003").
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Re: cut into part on y finish

Postby Gerry » Sat Sep 10, 2016 5:17 pm

I came across possibly the same bug that caused a hole in my part several months ago (year maybe?).
I sent the files to Robert, and he said that he found the problem and was able to fix it (I think, don't remember exactly).
But I don't think that there was ever a new release of MeshCAM 6 with the bug fix.
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