- Bring the component parts to the proper joining temperature;
- Using mechanical shear (usually brushing, scraping, or ultrasound), uniformly coat the joining surfaces of the parts;
- Using additional solder material to insure a completely filled joint, bring the surfaces together with additional shear (usually sliding the parts relative to each other or ultrasound);
- Clamp or hold the parts during cooling to maintain position and prevent the joint from spreading due to the surface tension of the solder material.
This general process applies to any metal or ceramic, with the resulting joint strength varying from 20-55 MPa (3-8,000 psi). Higher joint strengths in carbon based substrates (e.g. diamond, thermal pyrolytic graphite, foamed graphite), stainless steel, Kovar®, and other high performance materials are achieved by replacing the initial coating step with a proprietary heat treatment process that insures a permanent chemical bond to the material surface. It may also be possible to skip the surface precoating steps, depending on the geometry of the bond area and the substrate materials.
Variations of this generic process are practiced today in the production of thermal management devices, sensor housings, and sputter targets. A process for semi-automated joining using a multi-station carousel has also been demonstrated.