During the last 20 years, copper alloy use as molding and wear surfaces in molds has been expanding although the industry has been slow in learning how to properly and fully integrate copper alloy products into their mold designs.

The growth of copper alloy use in comparison to technological advancements with machinery, process equipment and resins has been limited by market acceptance, and in some cases, lack of understanding the available products.

An informal survey of molders and moldmakers still shows a large percentage believing that copper alloy usage in their molds is of little to no benefit. The belief is that copper alloys will not really reduce their mold cycles, will not improve part quality or will not contribute to other performance improvements. There also is fear of higher maintenance costs or higher initial mold costs.

Experience by molders has shown copper alloys actually do reduce mold cycle times, improve piece part quality and reduce mold maintenance costs. Moldmakers or molders that increase prices because of copper alloy usage are often just inexperienced with the product or just taking advantage of the situation. Typically copper alloy mold components show cost savings to the mold builder due to machining processes for those copper alloys that offset the additional cost of copper alloys over tool steels.

Beryllium Copper or Copper Nickel Alloys
Basically there are two families of alloy chemistries that yield high strength, high conductivity alloys that are the best choices for use as molding surfaces in molds. The families are either beryllium copper-based, or copper nickel-based. Both alloy families have other minor elements added for individualized purposes in each combination.

Even producers of beryllium copper alloys have been offering copper alloys without beryllium due to competition and continuing issues associated with beryllium-containing alloys. In some cases, manufacturers have created alloy designations or names that detract from the acknowledgement of beryllium content .

How to Choose the Right Copper Alloy
Bronze alloys or spinodal alloys are often mistakenly used as molding surfaces because they tend to be less expensive or readily available. Although for ejector sleeve, bushing and wear plate applications bronze and spinodal alloys work extremely well.

For molding details such as cores and core inserts, there are alloys that have five times the conductivity, making them a far better choice because the mold performance is not just slightly better, but drastically better.