AMPCO materials and their use in the production of injection molds and aluminum die-casting molds

As a mold maker and a company that repairs molds, we`re often asked what AMPCO materials are and why they are beneficial in mold manufacturing. The reasons are as follows:

• AMPCO alloys have a significantly higher thermal conductivity than tool steels.
• AMPCO alloys also have more even heat distribution.
• Thanks to this allows the optimization of thermal processes (cooling) in the mold, especially for difficult-to-produce plastic parts.
• Using AMPCO alloys also shortens the production cycle. Depending on the type of product, it`s possible to increase productivity by up to 80%, so plastic parts are produced more cheaply.
• AMPCO alloys have also sufficient hardness (there are also types with a hardness of up to 40 HRC) and high corrosion resistance.
• These materials can be quite well machined by CNC machining centers and by using EDM. The achieved accuracy is usually around 0.02mm.
• These materials can also be EDM sinked, in such cases, it`s advisable to use tungsten copper electrodes for types with the highest thermal conductivity. This is because AMPCO materials heat up quite a bit by EDM sinking, especially deep shapes, and the excavating process takes even longer due to the high body conductivity. Therefore, if we use graphite electrodes for EDM sinking, we have to count on their significant burnout. The accuracy of EDM sinking depends on the depth and type of shape.
  

Classification of AMPCO materials

AMPCO materials are copper alloys that can be basically divided into two main groups - brass and bronze alloys. Both groups can be distinguished from each other by color - brasses are more yellow (these are more used where it is necessary to achieve wear resistance) and bronzes are more red (these are more used where greater thermal conductivity is required).

In the production of molds, are the most widely used types under the AMPCOLOY brand, especially the long-proven AMPCOLOY 940, AMPCOLOY 95, and AMPCOLOY 83, to which the AMPCOLOY 972 and AMPCOLOY 944 types have been added. ATTENTION: Of these types, the following types contain Beryllium: AMPCOLOY 83 (1.9 %) and AMPCOLOY 95 (0.5%). AMPCOLOY 95 has the highest thermal conductivity and AMPCOLOY 83 has the highest hardness.

The hardness of these materials can be further increased by the fact that semi-finished products can be obtained as forgings.

And what are the disadvantages of AMPCO materials?

• Higher price compared to tool steels
• Machining of tool steels is easier
• When processing (including grinding and welding) with Beryllium content, suction is necessary, because Beryllium is carcinogenic
• More complicated welding of damaged shapes, especially with bronze alloys, because they have higher heat dissipation

For the welding of complicated shapes, the most suitable method is laser welding, where the most suitable types include QUBeCu25, QuCu38, QuCu80, QuCu81. These welding materials are available in diameters from 0.3 mm (some already from 0.2 mm) to 0.8 mm in packages of 100 grams in coil/tube design.