Optimal tool for isolation milling & validity check not working properly

Issue #521 new
Mike Snapper created an issue

Hello, I am using the flatcam 8.994 and when I was using the isolation routing tool I noticed an issue.

First I clicked the Optimal button to calculate the optimal size for the cutter dia, this gave me the result of 0.25mm which is indeed correct as the tightest spot on my PCB is the spacing between the pads of the chip in the picture, which is 0.25mm.

Then I checked the Check validity checkbox and generated the geometry. The geometry was generated and no error message saying that not all tools were able to complete the isolation warning was produced, so it seemed like all was well, but by chance, I noticed that there are two spots on the footprint which were not isolated, marked in the picture. So the validity checker tool gave me a false report (or lack thereof) that everything was fine. I tried to generate the gcode to make sure it wasn’t just a visual bug in the ui, and the blue toolpath also doesn’t go through there.

I tried to run the isolation routing several times to make sure it wasn’t a fluke, but it happens every time.

Getting around this is very easy, all I have to do is to change the isolation tool diameter to something like 0.249mm and then it isolates it properly. So this is relatively a minor bug, but the main problem is the false negative from the validity checker, it makes it look like everything is fine, which could easily lead to a disaster if the person doing the routing doesn’t visually notice the routing is incomplete.

Comments (1)

  1. Marius Stanciu


    I guess it’s a rounding error. This needs to be addressed by subtracting a small amount in the actual isolation like you saw yourself. Perhaps I will take something like 0.0001 from the known tool diameter and that should be within the tool tolerance so no big impact but it will allow the isolation to proceed correctly.

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