[RomanLini]

Hi, I'm coding up some software to import bitmaps and carve them as a "depth image" in the material.

Is there a standard rule of thumb etc when using a ball nose carving tool for the stepover value?

I have 1.5mm, 2.4mm and 3mm ball end cutting tools, and it would be great to have a ballpark idea of the best stepover values for roughing out and finishing.

Thanks!

[Pplug]

I've used 10% as somewhere to start on a 1/8 inch bit and 15% for a 1/16 inch. just try a test piece and see what you get. I think material has an influence as well. YMMV

[RomanLini]

Ok thanks for that.

I was thinking of 10% of the ball diameter but was worried it might be too coarse and leave horizontal lines across the job...

[metalworkz]

Hello,
I have been using .006" - .008" stepover for a .093" ball nose in aluminum and with wood with pretty good results on 3D carvings. That is a bit less than the 10% solution but if you don't want to spend time cleaning up some intricate 3D carvings you may want to adjust the 10% down closer to 8%. As with most things you will find the sweet zone for your particular situation after some trials but it is good to have a ballpark setting so you don't lose materail in the process.





Regards,

[RomanLini]

Thanks for the info metalworkz. I also got some more info from the "What's the smallest size tool" thread.

Looks like I need to make the stepover fully adjustable, which is going to require additional coding to morph between the image pixels, probably in 2D to cover both stepover resolution and line resolution...

[2ndSteel]

You should check out gwizard from cnccookbook. It has a function that you can input the height of the scallop you can live with and it will give you the step over to use. This is for ball mills. It has lots of reference and machining information in it.

[RomanLini]

Thanks! I'll check that out.