Cutting brass in a punch press

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ecdez

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OK, so I have a little project that would require a lot of 1 1/4" - 1 3/8" dia. brass disks (1/8") thick. I'm thinking the best way to get a blank is to punch it out of flat bar on the punch press with a round punch and die. I've never punched brass and I'm wondering if it's too brittle to get a good blank with this method. Will it fracture? Will it deform the edge to a point of not being worth it? Will it warp the blank?

I know there's probably not a lot of experience with something like this on this site but someone has to have crossed this bridge before with the wealth of knowledge around here. Anyone?

My other thought is a log of brass and slice it off with a parting tool. That's quite an outlay of $$ for materials and seems like a lot of waste with the parting tool but maybe not.

Any thoughts?
 
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Have someone waterjet or laser them from sheet, we get a good deal of thin blanks done this way, no heat from the waterjet and little from the laser, very little lost material as well.
I am currently running a lathe job from 360 brass hex bar, drill, turn, bore and thread then part off with a 1/8" wide parting tool. 1500 parts is 1500 1/8ths parted into chips, 15 1/2 feet of material gone.
 
If you do it with a punch and die put a scallop on the top of the die with the curve of a surface grinder wheel and lap the top of the punch. It will shear clean that way.
 
I would part them off with a P1-N parting blade - 0.04" wide so not a whole lot lost and you'll have a clean, unwarped disc.
 
I considered getting them cut but I have a price point I'd like to hit and once I send it out the costs add up quick. My labor is cheap.


4ssss said:
If you do it with a punch and die put a scallop on the top of the die with the curve of a surface grinder wheel and lap the top of the punch. It will shear clean that way.
Click to expand...

I just did some quick math and if I punch them out I have to use 1 1/2" wide bar and if I use rod I can use 1 3/8"d bar. Even if I use an 1/8" parting blade I would still save almost 30% in material weight by parting it off. I would use more labor though. Punching is pretty quick, basically as fast as the machine can cycle and I can index the next part. Probably somewhere in the 10-15 seconds each area. Parting and indexing the bar could probably take 20-40 seconds in a turret lathe with a collet closer. Not a huge difference but over 100 parts that would be 50 minutes at the largest spread. I guess for 100 that wouldn't be bad but if it grows beyond that it could make a difference.
 
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If you have a punch press, Then give it a try. It will depend on the alloy you use as to what the results will be.
 
If I had the punch and die I would have already took a chance at it :grin:.

Since I'll either have to make them or track a set down I though I'd get some insight first.

It's 360 free machining that I can my hands on easily.
 
Do you have a punch press? With the right punch and die it will work.. As any thing punched you can tell it was punched. Take a look at brass washers.
 
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I do, it's an 18 ton bliss. I was concerned about it warping the blank too.

I think for initial batch I convinced myself to get a thin parting blade and a short log of brass and go at it.
 
Where I used to work we bunched 1/16 al. on a bliss.
 
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