Meaning
High-conductivity copper alloys facilitate rapid heat removal from specific areas of a plastic injection mould. These materials, often marketed under the name ampcoloy, provide thermal conductivity many times greater than standard tool steels. They are typically used for cores and neck rings where cooling water cannot reach effectively.
Thermal Conductivity
Rapid heat transfer allows the resin to reach its ejection temperature faster than with steel alone. This property helps in eliminating hot spots that lead to part shrinkage or warping. The material draws heat away from the melt and moves it toward the water channels located deeper in the tool.
Mechanical Strength
Modern formulations provide the hardness necessary to withstand the high pressures of the injection cycle. While older copper alloys were soft, ampcoloy grades often reach thirty Rockwell C.
Wear Performance
Surface treatments help protect the copper base from the abrasive effects of glass-filled resins. Although the base metal is softer than hardened steel, ampcoloy performs well in non-sliding contact areas. Careful selection of the specific grade ensures the insert lasts for the duration of the production run.
This material choice prevents the need for frequent replacement of delicate gate inserts. Coatings like chrome or nickel are frequently applied to increase the surface longevity of the component.
