Layer manufacturing of heat exchange elements using photochemical machining, electroplating and diffusion brazing

A number of heat exchanger elements for a Stirling engine were designed but found to be very difficult to manufacture using conventional technology. E ach element required 1800 <1 mm oval holes through a 70 mm length of cooler . The elements were produced by repeated photochemical machining of 185 cop per sheets of 0.455 mm thickness. These were electroplated with tin and joi ned using a process known as diffusion brazing. This paper describes the sc ience and process of manufacturing these components. The procedure was comp licated by the need to integrate spigots at each end of the cooler, which m eant that some layers required selective diffusion soldering.