I am new to the CNC world and have a new job where I am taking on both the software side of icam and the hardware side of being the CNC operator. I have no prior experience running a CNC machine, so what I am dealing with is frustrating to say the least and I need help from someone who is familiar with material removal offsets.


The issue is....that if we upload the cnc program file with a drawing that is the actual size of what the counter top is supposed to be, the cutting tool will cut into the material 1/8 inch in from it's actual size so the finished product ends up 1/8 " smaller than what it should be. We have 1/8th inch stops in place along the edges.

If we offset the drawing from the actual size before programming in icam and go with a 1/8" offset to make the drawing larger than what it is supposed to be, it normally cuts okay... and takes 1/8th inch off the extra material and we end up with a counter top that is actual size. However sometimes it ends up cutting into the material by like an inch on certain angles.

Has anyone ever encountered a setup like this before when cutting granite or is this even normal for running a CNC program/machine to cut a piece of material to actual size of a drawing that we send to icam when programming a sequence?

Any thoughts on this would be greatly appreciated and should a Master 33 Inter-mac CNC machine normally be able to cut to actual size without offsetting a drawing to make it larger... just so it cuts to actual size in real life?