How do I make a tool for swaging copper plate ?

[picclock]

Hi everybody - hope you had a good xmas !!
I want to swage a 10mm hole in a piece of copper plate to get good thermal conductivity. Copper plate 0.7mm (may up to 0.9). 10mm copper tube onto which it fits. The copper plate is part of a heat exchanger. I have a heat exchanger done in this way from a phillips ice making machine and it looks like a really good job with about 4mm of swaged Aluminium gripping the copper pipe. So I'm guessing I just need to turn up the correct size tooling in steel and then use a press to achieve this. But basically I haven't got a clue where to start.

Any weblinks or reference book pointers on how this stuff works and how the tooling works to pierce and stretch a piece of flat metal to this shape much appreciated.

Best Regards

picclock 

[awemawson]

Perhaps a picture of what you are trying to emulate would whet our imaginations?

[picclock]

A picture of the philips will be on its way when I get to my workshop tomorrow. To clarify, a 10mm necked hole is made in the copper plate through which a copper pipe is fitted. The neck of the hole on the philips example is about 4mm above the plate surface, giving a large contact are and low thermal resistance. The pipe is an interference fit. I wish to make some tooling to emulate this.

Have found a picture of a larger one although the swaged neck is not clearly shown, however its the same type of construct. 

Hope this helps

Best Regards

Picclock

[vtsteam]

Seems like just a short tapered press punch and a longer die with a hole through both to accept the tube, and the punch and die shaped to produce the swage you want. Hole in sheet is a tight sliding fit on the tube. Slide it all together and press.

Crude short swage version would be to just push tube through a too small hole backed by a shaping die as above -- if the tube can stand the compression without buckling.

[picclock]

Hi
Pictures as promised. I'm thinking a 3mm hole in the sheet metal. The tooling (forming tool)with a 3mm slightly tapered end then a 30 degree taper to the final size (9.7mm). Not sure what to use as a outside support. sort of guess 11mm hole with 1mm radius edge (sheet 1mm thick). See Drawing. figure I could use silver steel and harden it for the forming part, and just mild steel for the female part.

All new to me so any advice welcome

Best Regards

picclock

[chipenter]

Your female part or Anvil will neen to be the dia of the pipe plus the thicknes of the copper by 2 , plus a litle bit of clearance or you may get them apart .

[picclock]

Hi

I have only tried this on Aluminium plate but it seems to work very well. Tool is as per earlier sketch. Raised area is 4mm which fits into recess of adjacent fin so that when compressed the fins clamp tightly to the tubing. Surprisingly low force levels needed to deform the metal - I just used my mill. Now need to arrange a second overdraft for the cost of the copper sheet

Best Regards

picclock

[steampunkpete]

Is there a particular reason why you want to use copper plate for the fins rather than aluminium?

Is the application such that you couldn't save a wadge of dosh by re-purposing a radiator out of a air-conditioning unit or a motorcycle / car?

What is it all for? Tell us more.

[picclock]

Two reasons to use copper fins. Thermal conductivity is near twice that of Aluminium so less and smaller fins/pipework for the same heat rransfer. Expansion of aluminium is near 1.5 times that of copper. As this is going to be temperature cycled differential expansion will loosen the joints. Can't tell you more about the application but space is limited as this fits inside a closed container.

Oddly enough I'm now comfortable about the swageing bit, but I am having issues with the simple bit of straightening 10mm soft copper pipe. Viewed a you tube video where the guy just clamped one end in a vice, and locked the other end in some grips and hit it with a soft faced mallet. I tried it and it didn't straighten at all. So I thought I would put one end in the work vice and attach the other end to the mill and use the slide to tension it. It ended up tipping the mill, but still no straighter. Another forum said use a car to apply the tension which I may end up doing. I also have an 8 ton force hydraulic cylinder so we shall see .. .

Best Regards

picclock

[hermetic]

I had to do exactly this job in steel sheet to make an exhaust system for a project. I went through a box of old hex sockets, found two, one with the right external diameter for the hole, and a larger one it would just fit inside, put them on some threaded rod, and pulled the small socket through the hole into the big one by tightening the nuts, worked like a charm and left the perfect swaged hole. I suppose finding the correct sizes was lucky, but it worked for me! If you have a press and can turn up the tooling, git er done!
Phil

[hermetic]

Just to add, you need sufficient clearance between the two sockets for the swaged material to fit in to and we all know that a bit of clearance never hurt anyone!
Phil