I am struggling with a good way to hold a ball shaped object in order to engrave and or machine parts of it's surface. I am interested in the different ways other machinists have used to hold this kind of difficult to control part. My part is the same size so custom tooling will be the order of the day. All I need is the best method. Any ideas would be appreciated.
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How to hold a ball to engrave or machine
(5 posts) (5 voices)-
Posted 3 years ago #
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Several ways we've used to hold parts with spherical or odd contoured shapes.
One way is to machine the first half the part leaving a picture frame around the outside and cast a resin around the part, turn it over and machine the other side. You can machine down to a parting line on each side of a sphere this way, just don't forget to wax the part so the resin doesn't stick!
Another way is to machine a mating shape into a fixture and use a vacuum to hold the part in place. It sounds like your making more than one part so his sounds like it makes more sense.
Posted 3 years ago # -
Can you use a "V" type clamp? If you are only Engraving.
TRRPosted 3 years ago # -
When cutting spheres on a lathe, I always cut the sphere shape out of the jaws leaving about 40% of the ball exposed to work on.
I've only once cut a sphere on a mill, and I used the same basic principle on soft jaws for a Kurt vise by cutting the spherical void into the jaws, leaving as much as I could exposed to work on. I had to reposition the spheres (ball valves in this instance) so I had to leave a feature I could align the part off of then go back and remove later as well. Worked good - I had to mill sensor pockets on the valve and wire grooves.
Rgds,
JohnPosted 3 years ago # -
Make a soft jaw for your vise that will hold the part and machine away. Your Cam program should give you the coordinates for the shape. If not I can give you a toolpath that will hold your part if you can provide local coordinates and sizes.
TomPosted 3 years ago #
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