Aluminum Casting

You could start your search here www.moldmakingtechnology.com

Regards,

Not sure if I should give a name of a company across these pages or not. But, it sounds like a investment casting would be your answer for the precision needed. Depending on the qty, cost could be quite substantial to produce.

David --

There are American foundries that have made vacuum compatible aluminum castings for the semiconductor equipment industry. Highly doubtfull that you'd be able to do -7 with a die casting. Likely any money you save will be lost in the necessary testing of each chamber. Look to other proven manufacturing processes.

Ed Weldon

In my opinion, it depends on whether you plan to maintain low pressure in the chamber, or whether it will be intermittently exposed to atmosphere. Aluminum outgasses more than most other metals and a casting contains a certain amount of porosity that creates virtual leaks. You can certainly count on extended pumping times if you use this method. I would think about making the chamber out of stainless steel. If you really want aluminum, I would make it out of plate and weld it together.

GA welderman. That's the way it's done in production in the world where the big money flows. Aluminum can be formed or extruded to reduce the number of welds. Extrusion dies that are simple shapes without hollows inside are relatively inexpensive and manageable in commercial applications where there is some quantity level of production. Design the weld joints properly with solid welds inside and skip welds outside. Otherwise you get virtual leaks. If you must cast in aluminum go to a sand casting foundry that has real experience with vacuum part casting. They know the tricks to control porosity. Still I think you'll have trouble at -7. Remember, that's below the vapor pressure of zinc at room temperature.

Ed Weldon

contact these people.

They made six similar size vacuum chambers for me and did it quickly. Although I bought stainless.

info@ldsvacuum.com

Find some one with vacuum experience. There are a lot of welding and machining procedures that can be done in ways so good vacuum is never achieved. Never use a Sulfur based cutting fluid, is just one.

You could try Kimball, don't know if they produce in aluminium though.