Beryllium-Copper

Some impressions cannot transfer the heat away quickly enough, leading to extended cooling cycles and often distorted mouldings. Beryllium-copper may be used to advantage in such circumstances. The copper is used for its high thermal conductance properties and the beryllium for its high mechanical strength.

The usual composition of this alloy is 1.7% beryllium, which gives a tensile strength of about 1200 MPa. Lower percentages of beryllium make the alloy too soft to use as cavity components, while higher levels impair the thermal conductance.

In its soft state, the material is readily machineable using most machining techniques including EDM. It will harden quite well up to around 30° Rockwell hut with ion implantation this may he increased by 15%. For extra durability the alloy may he hard nickel-plated; this is preferred to chrome, which tends to flake away.

This alloy may also be hobbed and pressure or gravity cast，although cold hobbing usually requires the alloy to be preheated to around 60-75 °C. Specialist suppliers carry out these casting processes.

Where the alloy is not in direct contact with the moulding material, it may have a much lower beryllium content. Typical usage would be as a heat exchanger inside a steel punch or cavity.

Beryllium-copper is extremely useful for short-cycling jobs where rapid heat removal is essential for short cooling cycles. For more intricate mouldings its properties are useful where rapid heat removal and better temperature control is required, often giving better quality mouldings.