Tool Stepover

Hey Les, It looks like the tool stepover is limited to 95% of tool diameter. Is there any way this restriction could be removed. or at least drastically increased to like 99,999%. Or maybe you can tell me a better way to do this… we use reground end mills A LOT around here and they are never ground to a standard size, just whatever it takes to clean it back up and be sharp again. So a 0.500" end mill might become 0.483". SheetCAM does the toolpath compensation automatically, so every time we get a “new” end mill or have to change end mills in the middle of a job, we have to head over to the office and repost the program. Huge inconvenience. We need to be able to set the tool diameter in the controller and let the machine do the compensation. My plan was to set the tool diameter to 0.001" and just set the stepover to whatever ridiculously large number is needed to work for the tool we are using, but I cant because it’s limited to 95%. Is there a better way to do this?

Sorry, that was a very long winded way to say I need to be able to let the controller do the tool compensation instead of sheetcam.

Increasing the stepover above 100% would be problematic. I’m pretty sure it would do some very odd things to the tool path.
You don’t really need that much accuracy to rough out the pocket. It’s just the finishing pass that needs to worry about the exact tool diameter. Maybe do the pocket in two operations, one to rough the pocket and one to finish. I have to admit I’m not too sure how to go about making it work with compensation in the controller.

I need to think a bit more about in-control tool compensation.

I was afraid you were going to say that. I suppose it would see that remaining material and try to go back and cut it.

I didn’t think there would be an easy way for rotary machines with pocket operations. For the jet machines its just a contour so I set the tool diameter to 0.001" and then I can use the OffsetLeft and OffsetRight to output G41 or G42 and let the machine do the compensation, but with a pocket operation that no longer works because of the tool stepover.

One thought I just had was to make it happen in the post. I can see it getting messy and computationally expensive quickly, but have to post do the math to offset the toolpath back to center of the tool based on the OffsetLeft and OffsetRight functions. That would require those to work at the right time and flawlessly, which I believe they may. It would just take a lot more testing scenarios to make sure. You would of course still have to program with a tool that is close to what you intend to use, but it would give you the flexibility to use reground tools. The only big issue I see is corner radii… everything would have to be sharp corners or radii greater than the tool radius.

Corner radii are a pain when it comes to tool compensation. Many moons ago I did look into in-control compensation and it raised all sorts of strange oddities with different controls. In the end I gave up on the idea because I was worried about the amount of extra customer support needed to tweak all posts to handle the different control idiosyncracies. The OffsetLeft and OffsetRight functions are vestiges from this testing.