AnsweredAssumed Answered

Shell vs scale

Question asked by Salted Fish on Apr 30, 2019
Latest reply on May 2, 2019 by Michael Paul

I am designing electrodes for EDM sinker and want to know the best method for reducing the size of the model to account for spark gap.

 

My own background, I've always used the Scale function to simply shrink the model. Say the model is 3" across, and I want a .005" undersize all around. I select the model and type in (3.00 - (2 x .005))/3.00 or 99.6667% and hit enter. The part is shrunk by ~.3% and the 3" dimension is now 2.99" I then export the model to my CAM program and I'm off.

 

However, the dudes I work with swear by the Shell command. To my understanding, the two are essentially the same thing, with the caveat that Shell will "wipe out" smaller features since it is (to the best of my understanding) creating an offset surface that might "cut off" features that are smaller than the offset. For instance, if there is a boss that is .005" across, and your shell is .005", the boss will be eliminated because there's no way to Shell the amount and keep it. In other words, any features equal to or smaller than twice the Shell amount will be eliminated in the final model.

 

I suppose I've answered my own question: Scale preserves the model in it's entirety, while Shell will eliminate certain features.

 

Is my reasoning here accurate and/or can others chime in with their experiences?

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