Changing tools during cnc operation

Hello all,

I have a part that I want to mill on my CNC mill, I use Turbocad to generate the .STL file, Deskproto to create the g-code and Mach3 to drive my mill.

My question is this, lets say I have a part that needs to have a lot of material removed, followed by intricate detail removal. How can I use a 3/8" endmill for the rough work and follow that by a 1/32nd ball endmill for the detail. I know I can run the program with the large end mill then re run it with the small one, the problem is that small endmill has to go through the process of "pretending to mill" the already removed metal. I think I have to have a new .STL file of the rough machined part, redo the g-code from that part with the small endmill, I just don't know how....any ideas???

John

I don't know Deskproto, but there must be a function to offset the tool center by the tool's radius to leave the part outline you want. Normally, you would make the G-code twice, with different tool radii for each run. The step-over and cusp size limits would be different as well to get suitable roughing and finishing passes with different size tools.

Jon

Thanks Jon,

There is offset capabilities for the tool size, the issue is that I need to have 2 STL files (I think) one pre and one post rouging. Or, I will have to let the finer endmill go through the motions as if the rougher had not already done its job, adding hours to the process. Just wondering if there is a "da" answer to this...like maybe I was missing something obvious (this does happen to me occasionally ;-)

John

Does the controller have block skip capabilities?

I don't see why, although I don't know Deskproto. The STL defines the object you are trying to make. It shouldn't change. The CAM program should do the best it can at carving the object with the selected tool, given the stepover, cusp size, etc. settings. Your CAM program does have a way to set all these things, doesn't it? Or,

Either your CAM program isn't really designed for this sort of work, or you are not using it right. How does the program know where the boundary of the raw stock is? That won't be in the STL file.

Jon