Negative start depth

[kstrauss]

I am making some rather small items which are about an inch in diameter. I would like to be able to roughly cut my stock to thickness, cut to the precise thickness in the CNC and then cut the actual features. To this end I setup a pass over the whole surface starting from -0.1 for a depth of 0.1 which should mean that the cut ends at a depth of 0.0. No error warning about the negative starting depth but Cut2d generated the toolpath to start at a depth of 0.1 and then go 0.1 deeper. Obviously not a good thing!

I understand that I can make an initial pass starting at 0.0 for a depth of 0.1 and then adjust the starting depth to 0.1 for all the other cuts. But is there any way to do what I'd like and not have to adjust the dozens of cuts in this job?

[IslaWW]

Kstrauss...
Your issue was caused by the negative number. Depth is distance from the surface, always appositive number, same as water.

There are numerous ways to accomplish what you want. One is to start with a material thickness of 1.1, do your surfacing, then set material thickness to 1.0

[scottp55]

We do a lot of virtually the same thing....Taking .25" stock down to various thickness's and then cutting.
We made a surfacing file in a separate folder, and all our design work is set up in separate folders for the AFTER surfacing material set up dimensions.
Actual dimensions in the cutting file is easier.
Eliminates fooling around in the cutting file as we have 3 dozen of them.
scott

[IslaWW]

Another way, and maybe the way that gives the best repeatability, is to zero the Z to the bottom of material, set the thickness at 1.001" and surface .001. Of course this means that your pass depth is the amount over 1". What this does do is ensure multiples are the same thickness and removes the need to rezero the Z after each part, especially if the thickness changes.