Producing several sample castings prior to full scale production services a dual purpose. First, the parts must be checked to the drawing to assure dimensional accuracy. Often the caster’s Quality Control department will inspect the tooling and several wax samples and calculate appropriate shrink factors to determine dimensions. In the case of relocating tooling from one foundry to another, this inspection procedure must still occur. Differences from one company to another in the type of wax used, shell building methods, and pouring practices may cause variations in shrink factors. Usually these differences will be minimal, but on critical dimensions they may be great enough to warrant a tool modification. Most investment casters will gladly tell you to what shrink factor your tooling was built. It is advisable to keep this information with your pattern records for future reference. In the event that tooling must be relocated at a later date, you can inform the new foundry exactly what type of tooling they will be receiving.

The second reason for running sample parts is to prove out the process engineering. Through continual process improvement, investment casters are constantly searching for ways to reduce their manufacturing costs. In the initial sampling process, the foundry may attempt several engineering methods to achieve the highest quality at the lowest cost. Even if tooling has been relocated and shrink factors determined, the investment caster will require that samples be produced and approved prior to releasing production orders. Wax injection methods, ceramic shell procedures, and metal temperature, will all need to be determined and monitored by foundry engineers.

The sampling stage is a critical period in all new product development, and proper communication and cooperation between the buyer and the investment caster is critical to ensure that proper quality and delivery requirements are met.

There are occasionally time sensitive projects that may require sample practices to be minimized. Whatever your need we can usually find a workable solution. Sample casting production is still the industry preferred practice. Start today by contacting us at