Testing the quality of castings in a jewelry shop is as varied as the objects themselves. Castings can be one-of-a-kind or mass produced. The metal used can be silver, gold, platinum with or without precious stones in a wide variety of shapes. The operations vary from the one-man shop to large industrial companies with all of the latest laboratory equipment. In general, non-destructive test methods are required using fairly expensive equipment.

This talk will concentrate on readily available methods that can be used by both the craftsman and the industrial producer. The modern techniques such as x-ray and ultrasonic testing will only be mentioned briefly.

For the caster, the most common problem is porosity. Density measurements are easy to do, can be automated, and give quantitative data on porosity. Bending and filing tests give information on ductility and porosity. Simple magnetic tests can give hints on nickel and cobalt concentrations. The use of standard test models gives information on a wide variety of things such as mold filling capacity, surface structure, and reproducibility of fine details.

The talk will focus on certain critical defects, their occurrence and detection. It will also discuss their prevention starting with correct melting procedures and include a discussion of the relevant casting parameters.

Author: Christoph Raub