Aluminum Alloys

There is a noticeable trend towards the use of aluminum alloys for medium- to high- volume production in theUK, theUSAand increasingly in mainlandEurope.

The principal advantages of this material are:

                 It costs less than steel.

                  It has good machineabilty: it machines up to 5—10 times faster than steel.

                 Distortion from machining h minimal compared to steel owing to a special heat treatment of the material during prod action

                  The thermal conductivity is excellent, much higher than that of steel, which promotes rapid and efficient heat removal from the mold during molding.

                  Cavity forms can be made using EDM techniques at a rate of up to six times faster than steel.

                  The weight of aluminum alloys is less than that for comparable sizes of steel*

                  It may be chromed plated or anodized to reduce wear and corrosion.

                  It can be polished and etched in the same way as steel

The main disadvantages of this material are:

                  The modulus of elasticity is only 30% that of steel.

                  It cannot achieve the same levels of hardness as steel.

                  As it is mechanically weaker than steel, plate thickness have to be around 40% greater than with steel.

                  Wear is greater and the material bruises more easily.

The service life of aluminum alloy mold tools can quite readily achieve around 200 000 shots depending on the molding conditions. There are a few notable exceptions to this where longer service lives of up to a million shots are achieved for straightforward parts, although certain mold party may have to be replaced because of damage and wear*

There is also an increasing use of hybrid aluminum—steel mold tools in which the advantages of both materials are used to best effect — steel for high-wear and aluminum for less critical areas and where high rates of mold cooling are desirable.