Anyone "punched" or crimped sheet metal together?

[SRT Mike]

Does anyone have experience with using a punch and die to squish two pieces of sheet metal together? What I mean is, lets say you have two pieces of 12"x12" metal - say brass and zinc and you want to attach them together but you cant use rivets or glue or fasteners. There is a process whereby you have a die (imagine a 1/2" round piece of metal with a hole in the center, maybe 3mm diamater and 3mm deep. The die is mounted in a tool - like a press, in the bottom. Then you have a punch - 1/2" diameter with a small protrusion on the end, maybe 2mm diameter, 2mm deep. This goes on the top of your press. Then you lay the two sheets of metal together and when you "punch" them with your setup, it creates a dimple in the metal. At the microscopic level, the two metal sheets are deformed together and they actually sort of weld to each other.

Anyone know a specific name for this process? And does anyone have any experience with it? The application is attaching LED lights with flat tabs coming out of them. The tab is about 1/2" square and bent at 90 degrees to the body of the LED so it sits flat. These LEDs are meant to be attached with this crimp process to a pair of copper or tin conductors. The LEDs are sensitive to heat and cannot be soldered. Using a series of solderless terminals would be too time consuming. Conductive epoxy doesnt work because the tin and copper go through a galvanic reaction and the joint fails. The manufacturer recommends what they call a "clinch joint" which is like what I described above. Problem is they sell the machines, at about $200k each! After investigating it, its really just a crimp with a punch and a die. I think I could CNC machine the parts I need and mount them in an old press and get what I need. The OEM machines have all sorts of robotic functionality that I dont need, so I just want to devise a setup to do the actual crimp.

Any ideas?

Thanks!
Mike

[vladdy]

I have done, well I suppose it could be called riveting, similar perhaps to what you are looking for..
The process was to drill a hole [around 3/16 in my case] in the harder of the two, and then push the softer metal through slightly, and then using a pointed punch, flare the softer one over a bit and it deformed enough to slightly flare over and grab..
you could also probably put a small hole in the softer one, and then roll flare it through and over on top of the harder one..

not sure if this is what you are lookin for but??

enjoy

[lwill]

One name for it is "clinching"

http://www.twi.co.uk/j32k/protected/...kschjg001.html
discription of how the proccess works, basicly as you described it. The punch bottoms out causing the material to bulge out at the bottom. The hard part will be making the part of the die the metal enters at strong enough yet be able to open somw how and let the "bulge" out. It looks like they use something similar to a collet with individual fingers.

http://www.multicyl.com/
look at their MultiLoc

http://www.eckold.ch/umformen/e_um_Homepage.html
see Hit-Clinching

I got a card in an "Tech Deck" info pack a while back with another company. But I can not remember or find it. They advertise in NASA Tech Briefs magazine, but not listed in the advertisers section on their sight. http://www.nasatech.com/ or http://rs.ims.ca/nasatech/webcard1.asp

Good luck.

[SRT Mike]

Originally Posted by lwill One name for it is "clinching" http://www.twi.co.uk/j32k/protected/...kschjg001.html discription of how the proccess works, basicly as you described it. The punch bottoms out causing the material to bulge out at the bottom. The hard part will be making the part of the die the metal enters at strong enough yet be able to open somw how and let the "bulge" out. It looks like they use something similar to a collet with individual fingers. http://www.multicyl.com/ look at their MultiLoc http://www.eckold.ch/umformen/e_um_Homepage.html see Hit-Clinching I got a card in an "Tech Deck" info pack a while back with another company. But I can not remember or find it. They advertise in NASA Tech Briefs magazine, but not listed in the advertisers section on their sight. http://www.nasatech.com/ or http://rs.ims.ca/nasatech/webcard1.asp Good luck.

You know, here's a good idea for an entrepreneur... start a company where you can virtually "buy a beer" for someone. Someone does you a favor, you "buy a beer" and a few days later a nice frosty cold one (in dry ice) gets delivered to their home.

What you posted is exactly, exactly, exactly what I am looking for. THANK YOU! The funny thing is, the manufacturer claims the LEDs get attached with their "Patented clinch technology". I wasnt sure if it was the attachment method or the machine. Looks like its their machine thats patented. I waste lots of $$ hand soldering them just now, and my one hope (conductive epoxy) failed miserably in testing. I cant imagine that the clinching would be too expensive, and finding companies that sell dies and machines is icing on the cake.

Thanks again!

[lwill]

I sort of remembered the name and just found this:

http://www.btmcorp.com/tlmachines.html

they might sell you the dies