Aluminum alloys are differentiated by the manner in which they are produced: when manufactured, they are either a non-heat treated cast material or a heat-treated wrought material.

On one side of the spectrum, non-heat treated material is ideal for low-strength mold applications. Cast products typically display lower strength and provide excellent dimensional stability. Also, cast alloys provide excellent machinability and minimal residual stress. Though not engineered for high strength, cast material is suitable for some low-pressure injection molds and straight injection molds requiring less than a few thousand shots.

On the other side of the spectrum is the high strength, heat-treated wrought aluminum alloys. These alloys are technologically advanced alloys with enhancements in heat treating, aging practice or a combination of both. These products exhibit high strength (relative to cast product), excellent machining and polishing characteristics, as well as dimensional through-thickness consistency.

These aluminum alloys are suitable to mold nearly 75 percent of all unfilled resins—including PP, HDPE, Nylon, PET, ABS and PE. Molds manufactured using high strength aluminum have been known to successfully run millions of shots. Obviously, proper tool design, setup, running and maintenance of the mold must be adhered to.

In the middle of the spectrum are what can be referred to as common alloys—such as 2024, 6013, 6061, 7050 and 7075. Common alloys are manufactured at facilities in accordance with the Aluminum Association procedures for manufacturing these materials.