Aluminum molds continue to be used primarily for R&D, prototypes and lower volume production. However, today there are several high strength, heat treated wrought aluminum grades available with improved durability that actually make it a preferred choice for certain types of high volume production parts.
One of the primary benefits of aluminum is the thermal conductivity compared to steel. Thermal conductivity is a material’s intrinsic ability to transfer heat. The thermal conductivity of aluminum is approximately five times greater than steel. As a result, 25% faster cycle times can often be achieved using aluminum. For tool designers, the proximity and number of waterlines becomes less critical allowing greater access for locating lifters and ejector pins in tight spaces if necessary.
Another benefit of aluminum is the plastic material fills faster, more evenly, over longer distances and with less injection pressure. Long, larger, more complex geometries can be produced with lower molded in stress resulting in less warp and more dimensionally stable parts which translate into lower scrap rates.
When it comes to plastic the best material candidates for aluminum are unfilled grades of polyethylene and polypropylene. Unfilled nylon, polyester, ABS, and polystyrene are good candidates as well. Glass reinforced or filled materials are abrasive and can cause premature wear especially in high shear areas so these are not recommended. Also specialty materials requiring very high mold temperatures be maintained (eg. Polyetherimide-aka Ultem) do not benefit from the thermal conductivity of the aluminum.
AGS Technology has extensive experience designing, building, and running production grade aluminum molds. During the request for quotation process AGS Technology will evaluate and recommend a production grade aluminum mold if it is a good fit. In today’s competitive environment, these benefits cannot be ignored so AGS proactively makes these recommendations to provide its customers the most cost effective, high quality part.