double sided job setups

[july_favre]

How do you guys set up a double sided piece on the mill so that both sides line up with each other? For a job i am working on I was going to make a hole through the stock and reference it as 0,0 on both sides and work in the negative on one side and positive on the other.

[M_D]

I'm not positive what you are asking. Is it how to machine one side of a work piece, then flip it over and have it located the same so features on both sides are in perfect relationship to one another?

There are several ways, and which way is best depends on the accuracy needed, how many parts you are doing (in other words what level of sophisication is justified), and the part feature.

One can use through dowel holes and screw or clamp the part to a doweled fixture plate.

You can flip it in a good vise, and dial in in with a dial indicator or edge finder, referencing from edges or holes.

If you were to give more details I should be able to help with more exact information, if you still need it.

[nervis1]

It starts at the computer, generate your top machine tool paths and post it, then in the CAD software flip the part and locate the origin in the same place, example: for the top the origin can be X-, Y-, and for the bottom X-, Y+, you can use a hole center as well.

That way the stock origin is the same for the top and bottom, this assumes that your stock has no draft BTW. Generate the bottom tool paths and post as a seperate file.

Set fixture offset for the top, run the progam, flip the part in the same direction you did for the CAD file, re-set the fixture offset, and run the bottom side program.