Punch engraving

[Parameter]

I've got a client which need to have punch tips engraved with small logos for punching wood and plastics. Those are REALLY small... kinda 3/8 to 1/2...

The guys who does the job usually charge 200$ per punch to do the job but has a 100,000$ machine... But here is the winner, this client need about 60 of them and more in the future. We have a great relationship so if I can deliver this job I'm probably good to keep the shop open as it will bring steady job.

Can someone give me an idea of how it's usually done (machining wise). I've got some fine tools and am currently building this machine:

http://www.pathcom.com/~vhchan/cnc/cnc.html

I have my 3 axis router to cut parts which help a lot and if needed I could build a machine that does 2 x 2 x 0.5 and have 0.001 precision too.

I need stiffness that my current router does'nt deliver for the steel punch engraving. It's about .03 high with a ring all around.

I'm essentially into verifying how I can machining the part. It's one drawing, but many units... If I can get the contract, I don't mind doing a rfq for the CAD itself...

Can this be engraved/machined or it need some kind of other process?

Might try making a stencil, mask the area with ceramic and sandblast? Your tought on this?

Para

[lerman]

This is just really a guess --

Use EDM. I believe there is an article somewhere on the web about building a sinker EDM machine inexpensively. A think you should be able to make the form out of carbon (easy to machine) and then EDM prehardened punches.

I'll bet someone out there will know if that's a reasonable way to go.

Ken

[txcowdog]

Try photoengraving the tips and then mount that on the punch. Any amount of fine detail can be achieved through photoengraving and the minimum charge is about $24 for 16 sq. in. You could do several at one time on the same plate then cut them apart and mount the separate dies on the individual punches. The photoengraver we use can be found at http://www.owossographic.com Just email them your art by 10:00am eastern time and they will ship the same day. We use magnesium plates for embossing leather on a 25 ton press and the plates hold up quite well so I imagine there would be no problem using the same plates with a hand punch. Good luck with your endeavor.

[Parameter]

After a bit of study, I was thinking of making a sinker EDM with my actual router and have the sinker machined to spec by some specialized shop.

Photoengraving seems to be pretty cheap but I dunno about precision. Those are 3/8 diameter punch!

Could you enlight me a bit on the process? I can build almost anything, router, edm, foundry, why not photoengraving?

Parameter

[txcowdog]

The photoengraving process is an exact reproduction of your artwork. I mean EXACT!! You could not machine a part to the same tolerances as a photoengraved plate. They take your art, print out a negative and lay that on a piece of magnesium that has a photosensitive coating. After exposing this to light it is washed in a special chemical that washes away everything except your image. The plate then goes into an acid bath where everything except your image is etched away by the acid. So you see, the image is an EXACT reproductoin of your art. There is absolutely no variance in what your art looks and the final size of the stamping die.