Problem with simple job?

I’m trying to mill the little divot in picture 1 into the side of a part.

I am using a 5mm tool.

If i have 0.8mm finish allowance it works.

If I have my normal 0.1mm finish allowance it fails.

The slot is 5.4mm wide so I can’t see why the issue???

Having a slot that is exactly the same width of the cutter plus finish allowance can confuse SheetCam. You are right on the very edge of either cutting that slot or not cutting it. Floating point numbers are not perfectly accurate. For instance 5mm may actually be stored as 4.99999999999mm. Numbers are always rounded up when they are displayed so you never see this tiny error. However after doing the path maths you can end up with the situation where the numbers work out so that the cut is preserved on one side of the slot and removed on the other side of the slot. You now have an open contour and things start getting ugly.

Borderline cases like this are very difficult to program around and fixes often have other unwanted side effects. I do have an alternative path generation algorithm in the pipeline that should be more robust in borderline cases but it involves some major rewriting of SheetCam’s core code.

If i have 0.8mm finish allowance it works.

Did you mean 0.08mm? You will probably find that 0.099mm will also work.

Are you also sure your slot is 5.4mm wide? If your cutter is 5mm and you are using 0.1 finish the problem size should be 5.2mm.

Thanks Les, I thought it was odd too as the slot is indeed 5.4 wide so in the end I shut everything down and rebooted - this seems to have cured it!

I had been importing and testing stuff all day so maybe something in CAD or CAM got a little fed up :slight_smile:

Anyway its sorted now.

While your there, is there a way you add to the FULL job report stuff like lead-ins and outs and any other little bits of info that are not shown like corner sharpening and so-on???


The report generator isn’t currently set up for that information. I could look into adding it.