Projecting toolpaths onto a sphere

[Andris Skulte]

Hey guys - I've been lurking for quite a while, and y'all seem to have great (and very different sometimes) suggestions.

 

Background - I'm projecting a logo onto a 2.25" sphere, to be machined with a .015 endmill (.004 deep). I have the logo at Z0.0, and create a toolpath with a retract height of 1.3" and feed height of .100". I project it onto the arc that defines the sphere (0,0,0 is center). The logo is projected just fine, but the feed height stays the same (at .100). I have been setting the feedheight at 1.3", so the cutter stays above the sphere, but it then feeds down to the part at F5.0. I'd like it to rapid down to .100 above the surface of the sphere, and then feed down. Is this possible? I've tried changing the feed height from abs to inc (didn't do it) as well as turning on "add depths", but of course, that won't do it. Has anyone else run into this situation? I'd go ahead and edit the nc by hand, but this type of work is recurring and a proper fix sure would be nice. Thanks for any advice!

 

Andris

[Zero]

Hey Andris,

 

I do this kind of stuff alot too. In the original pocket program, set the Clearance and Retract both to 1.3 and absolute. Set the Feed Plane to .1 incremental. Set the Top of Stock to 0 incremental and the depth to -.004 incremental. Then in the surface project toolpath, set the Clearance, Retract and Feed Plane all the same as before. Check the add cut depths box on. This should do what you want.

[fhode]

Andris:

This is what you should do,

 

1.Make a 2d operation of the logo with the final depth cut set at z0. So if you are using depth cuts, they will be Z positive. Set the clearance, retract, and feed heights all well above the depth cuts.

 

2.Instead of projecting onto an arc, make a revolved surface out of the arc. This surface should represent the shape of the final cut. The highest point on the surface should be below z0. This way you can use SURFACE-FINISH-PROJECT.

 

3.In the Projecting operation, set clearance to 0.1 abs, retract to 0.1 inc (you can change this to a higher # if you see it is gouging in rapid moves after retracting and moving to a different point), and feed to 0.1 inc. Select the 2d operation, and activate the add depths option.

 

This definetely should work for you, I do this all the time on detail work on my shoe sole molds. If not, send me the file and I will gladly take a look.

[Andris Skulte]

Zero & Fhode - Thanks for the tips! I was actually using the "project" function right from the operations manager, rather than the "surface" function. I tried them both, and it seems to work. Thanks again!

 

Andris