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Designing a Rotating Arm Jig

Designing a Rotating Arm Jig

Designing a Rotating Arm Jig

Hi all,

Me and my team are about to design a jig that holds a copper blank and movable in rotating motion. Our goals are actually to grind a layer (around 1/2-1mm thickness) of curvature face of a copper blank. We are not making a new one but instead grinding an existing one. We would like to try on milling method to get smooth and even surface instead of using manual grinding. We had come out with a concept of designing a rotating arm that will hold the copper at the end of the arm and cut with a stationary milling bit but we are not sure whether it is practical or not. Can someone help us on this? Thanks.

RE: Designing a Rotating Arm Jig

Copper doesn't grind well; it clogs the abrasive.

Copper has been turned in air bearings and peeled with a diamond edge to generate curved optical surfaces.

Cutting anything at the end of a long arm is problematic, because the forces associated with cutting or grinding are quite substantial, and will cause deflection of the arm. Worse, the dynamics of the interaction between the arm's flexibility and the cutting forces will cause chatter and other vibration related problems.

Try first to understand how a lathe works, and how a radius tool is used with a lathe to make objects like lenses.

Mike Halloran
Pembroke Pines, FL, USA

RE: Designing a Rotating Arm Jig

What size of radius are you generating? If the radius is not too larger than 7" you could setup a faceplate fixture on a lathe and turn the OD as your radius. You did not give any quantity numbers and the expected savings for doing this work.

Good Luck

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