Matching Tool Steel Selection to Initial Production Commitments
Match tool steel hardness and chemistry directly to committed shot counts and resin abrasiveness to prevent premature cavity failure and tooling cost overruns.
Aluminium 7075 T651
Meaning
High-strength zinc-alloyed aluminium plate supplied in a stress-relieved and artificially aged condition is a common material for prototype and low-volume injection mould tooling. The specific grade aluminium 7075 t651 offers mechanical strength that approaches that of mild steels while maintaining the machinability and high thermal conductivity of aluminium. This material receives a solution heat treatment, followed by controlled stretching to relieve internal stresses, and is finally aged to achieve maximum hardness.
It is typically utilized for rapid tooling where low lead times are critical.
Alloy Tempering
The thermal treatment of the alloy provides a yield strength of over five hundred megapascals. This high strength-to-weight ratio allows the material to withstand clamping forces during moulding. Controlled stretching prevents distortion during milling, which ensures that the cavity plates maintain tight tolerances.
Moulding Suitability
Rapid heat dissipation from the aluminium plate reduces injection moulding cycle times by cooling the polymer part much faster than steel tooling. This high thermal conductivity minimizes part warpage by ensuring uniform cooling across the cavity walls. However, the lower surface hardness compared to tool steels means that the mould is susceptible to erosion from glass-filled resins and must be restricted to unfilled polymers to prevent premature wear.
Economical Benefit
Low machining costs and rapid production of prototype tools reduce the time required to bring a new plastic part to market. The ease of machining translates into reduced cutter wear and faster cycle times in the toolroom, lowering the initial tooling capital expenditure. For short production runs of a few thousand parts, this material avoids the high cost of steel tooling while providing fully functional moulded components for evaluation.