Holding Flat Stock on a mill

[John Lorbiecki]

Hi all....

Enjoy all the talk on the site and want to discuss various methods that you use for holding flat stock. I do alot of 3 axis work on various materials, but it is primarily acrylic, delrin, and aluminum.

I have been using double sided tape (VHB) on the plastic stock and mounting it to a cutable base material- mostly acrylic. This allows me to machine the center and perimeter of the part all in one set up. The base is then bolted to the table or held in the vice. Of course, this doesn't work with aluminum.

With aluminum, I end up either putting it in the vice and hope that the final perimeter cut will allow the part to drop (or make tangs to keep it in place) or making a fixture using screws to hold it to a base material and cut away.

My thinking behind all this is to cut the entire piece all at once, both internal features and perimeter features.

So, what way do y'all do something like this? I know that there are vacuum tables, but would perfer not to have to make one to use....

Thanks!!

John

[DareBee]

Do the aluminum the same way.
http://www.miteebite.com/products/mitee_grip_e.html

[John Lorbiecki]

The concern with doing it the same way is the heat and coolant will attack the tape and loosen it up....

[DareBee]

Did you look at the link I posted?

Not an issue if you machine properly.

I have also used epoxy to hold parts to sub-plates. The downfall to this is that your subplate and the epoxy will need to be machined off when you are done.