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View Full Version : 3 axis lathe/mill hybrid design.



GordonFreeman
07-02-2017, 10:02 AM
Hi, I use my current homebuilt horizontal CNC to make thermoforming(vacuum forming) molds for 1/10 scale RC car/truck bodies.

I use several steps to get to the final mold including cutting foam and pouring a rough polyurethane casting and then final machining the polyurethane to final dimensions and detail. The final result is great, but there are alot of steps and I usually have to use 5 "setups" to get at all the undercuts and fine engravings on the "top" and "4 sides" of the mold.

I was thinking that I can cover "a slice" of the surface in 2-axis (y and z) and then if I had a tipped rotary table (3rd axis) I can then rotate the mold with CNC and cover the whole mold and undercuts with only a 3 axis movement. I'm not entirely sure how I'd CAM the g code, but that could be worked out I think.

It would probably just be like an indexed lathe with a spindle on the 2 axis. The spindle could be semi-permanently tipped to get at the top and undercut sides. Or the whole 2-axis CNC part could be tipped relative to the lathe axis.

I've seen "statue like" parts cut on lathes, so imagine more of a "turtle" shape (flatter car body) being cut on a CNC lathe.

I think it would help minimize cutting right at the bottom (tip/center) of spherical BEM cutters.

Does that seem reasonable? There are probably cases where this machine couldn't access every point on the mold, but it seems to me that most car body shapes could be "radially sliced" and it would be a "single path".

It would be somewhat like a "turntable line laser scanner" if that helps you visualize what I'm trying to describe.

I'll get some pictures and maybe a video of my idea to clarify later.

Ideas, thoughts, possible problems?

Thanks for the great forum.

GordonFreeman
08-02-2017, 12:05 AM
Here's a pic of the idea. It could also be thought of a 3axis mill with a tipped rotary table, but without an x-axis.