Cost reduction of multiple milled parts

[Tech2]

Sometimes you can reduce the cost of milling jobs by combining two or more parts in one design and using Comments To Machinist to saw the parts apart. This reduces setups. However the connection between the parts must be solid material. Weak links create work holding problems. Also note that the tolerance of the saw cut is relatively low.

[keness]

Just how solid do you need it to be in order to be convenient and easy enough to work with?

I have some square bar nuts about 2 inches long that I was planning on doing 5-up end-to-end.

Is the cost for sawing/breaking them at the joiner-gap (see my file to see what I did in my design) just the cost of the CTM or is there something else to it?

Please see attached and let me know if this is sufficient? If not, how thick would you like the "joiner" to be?

Thanks!

[Tech2]

For a design like that your link is a bit too weak IMO. I would remove the recesses and just saw the parts apart. You would also reduce cost further that way. The cost will be computed manually for the Comments To Machinist for the sawing.

[keness]

Thanks for the input!

Is there any guide on what the sawing would cost? It is difficult to decide if I would like to go that route without knowing.

Or, since the difference in cost with and without the recess isn't too much, I could separate them myself. In this case, I would prefer to have the recess as it will make it easier. How thick do you need the joint to be? Material is steel, so it isn't exactly flimsy.

Easiest, of course, is just doing them 1-by-1, but at production quantities, the difference rapidly widens.

If there is a better way to make a piece like this, please let me know.

Thanks!

[Tech2]

There is a trick we can use on the mill so you don't even have to saw them apart. Just model a joining thickness of say .005" and add Comments To Machinist "Mill as separate pieces". The total length can be up to about 16" and this is only for small parts like yours.

[keness]

Thanks! That's perfect.