Injection molds are becoming the process of choice to produce large volumes of parts at a relatively low price. Most of the molds used today start out as aluminum mold blocks that are refined and precision machined to create simple to very elaborate shapes in the mold form.
This process is done typically by a toolmaker or a moldmaker. These individuals are often engineers with extensive experience in both injection molding as well as in working with the different aluminum alloys. The complicated the molded part is the most important choosing an aluminum alloy with excellent machinability will be.
The Benefits of Aluminum
Aluminum is a natural for injection molding for several reasons. First, most of the alloys are considered excellent when it comes to machinability. This means that they mold cavities themselves can be created within the block to very high tolerances to tight specifications. This, in turn, results in highly precise parts that are uniform, consistent and very high quality.
Additionally, the aluminum mold blocks are often lower cost to use than other materials. Quality aluminum alloys are not initially cheaper in price; this is important to note. However, the aluminum is highly resistant to corrosion and surface degradation, allowing for hundreds of thousands of parts to be produced before the mold will need to be replaced.
The more parts that can be produced per mold, the lower the cost of production is over time. Additionally, it is not cheap to continually have to produce the molds. By utilizing aluminum the lifecycle of the mold is greatly extended and therefore the overall costs of operation are dropped considerably.
Heat Dissipation
Just as aluminum is often used in heat sinks, busbars and even with other electrical components, the ability for aluminum to quickly dissipate heat makes an aluminum mold blocks that a very natural choice.
Injection molding can only occur when the mold itself is at a specific temperature compared to the heated resin or thermoplastic material is actually injected into the mold cavity.
With the use of aluminum, heat after the resin or thermoplastic material is injected is quickly moved away from the areas of contact with the injected material. This allows for quick cooling from the surface. Additionally, as the heat continues to dissipate at a uniform rate the cooling is predictable for the molded part, allowing for easy setup of a fully automated system.
