Guangdong Coyo Precision Machinery Manufacturing Co., Ltd.


What is Aluminum Injection Molding?

January 06, 2023


Aluminum injection molding is an innovative technique based on injection molding used to produce parts (either prototypes/real products) with aluminum tooling. It is a perfect alternative to steel injection molding in rapid prototyping and has wide adoption in automotive, aviation, and industrial processes.


Aluminum mold is ideal because it guarantees an easy production of complex products with minimal parts. Also, it guarantees stable products with consistent structures, high accuracy, and smooth surfaces. This results from its properties such as its ability to effectively transfer heat from the mold and guarantee faster product formation.

What is Aluminum Injection Molding?cid=4


Features of Aluminum Tooling for Injection Molding


Aluminum is useful in tooling due to its many properties, which aid in creating low-volume injection molds at a reasonable cost. Of its features, below are the important ones that make it ideal in aluminum injection molding and tooling in general.


· Thermal Expansion and Cooling rate

Aluminum has a high coefficient of thermal expansion. Therefore, after heating to the right temperature, it can easily cool down which makes production fast.


This makes it an important material in the product manufacturing process that requires fast and effective production. It also makes it ideal for the injection molding process.


· Metallic Properties

As for workpiece accuracy, a tool that has adequate mechanical strength and rigidity is necessary. Aluminum has strong metallic characters, which maintains its rigidity and strength to a certain level. It is also ductile making it the right material to use tooling.


A tool must be strong enough during the manufacturing process. In aluminum injection molding, the correct choice of cutting parameters, grades, and geometries will also lead to a more efficient aluminum molding process. Therefore, aluminum alloys used in tooling will increase productivity while lowering the cost per component ratio.


Advantages of Aluminum Injection Molding


· Cost

Aluminum injection mold cost is lower compared to steel in manufacturing an injection mold. The overall worth and return on investment of a mold can depend significantly on mold usage. Nevertheless, the initial tool investment for aluminum is less if all other factors are equal.


· Lead

Aluminum molds guarantee a faster path for the production of products. Steel injection molding can take months from designing the mold to realizing the final product. However, aluminum injection molds only require days to create molds, prototypes and make final products.


· Good for Low Volumes

For low-volume batch production of parts, aluminum plastic injection molds offer better value. This is due to their reliability in providing lower upfront costs and producing reliable parts in thousands.


· Machining Time

Aluminum prototype molds dissipate heat much faster than steel molds. Hence, they can heat and cool much more quickly. During injection molding, the cooling time accounts for the overall cycle of the molding process. Therefore, choosing an aluminum molding process allows a shorter cycle, which translates into the faster production of parts.


· Better Products

One of the biggest reasons for defects in parts such as sink marks, voids, and burn scars is non-uniform heating and cooling. The excellent heat dissipation characteristics of aluminum molds provide an advantage of allowing the mold to heat and cool quickly and uniformly, thereby reducing the number of defective parts and rejects.


· Easy Repair and Modification

Due to steel's extreme hardness, damaged or deformed steel molds may prove extremely difficult and expensive to fix. Often, a new mold is the only solution. However, aluminum plastic injection molds are from softer materials, and their design is separable and straightforward. This feature makes it easy to repair and modify in case of an error in the aluminum injection mold.

Disadvantages of Aluminum Injection Molding

· Durability

Aluminum plastic injection molds are suitable for smaller part runs. However, steel molds are more durable as they are corrosion-resistant, wear-resistant, and thermally stable. This allows for the production of more products.

However, engineers can replicate the same durability of steel by nickel-plating or annealing aluminum mold design. It would increase aluminum injection mold cost which will negate the cost advantage associated with aluminum tooling.

· Limited Surface Finish

Aluminum plastic injection molds offer limited surface finishes compared to steel molds due to their low density. The high density of steel allows for various texture selections and custom finishes by adding steel inserts.

· Flash On Part

Flashing is the formation of excess material on a mold due to worn-out cavities that no longer fit tightly. After several thousand production cycles, aluminum plastic injection molds will wear out and have non-conformities, leading to flashing in the product.

· Fewer Products

Aluminum injection molding cannot withstand the intense temperature and pressure associated with injection molding processes for extended periods. Therefore, they are not ideal for long-term and high volumes of part production.

· Complexity

Engineers cannot improve aluminum mold design in case of a need to make modifications due to the ability of molded parts to impact the mold. However, steel molds can be toughened via heat treatment to handle developed materials of varying densities.



How Long Does an Aluminum Injection Mold Last?

The lifespan of an aluminum injection mold depends on its use in product manufacturing. When used for prototyping, aluminum injection molds can produce a few thousand parts due to the density of their molds. However, the lifespan shortens when used for intense product manufacturing.

In recent times, processes such as surface coating and anodizing have been incorporated to improve the durability of aluminum molds, making them useful in production cycles.


Is Aluminum Injection Molding a Better Option Compared to Steel Injection Molding?

The use of aluminum or steel injection molding would depend significantly on the nature of your design and the type of products you intend to achieve. While both injection processes are complementary alternatives, they both provide distinct advantages and disadvantages that engineers must consider before adopting a manufacturing process.


We at Coyo provide optimized aluminum injection molds design in product manufacturing. Consult with our support team for manufacturing advice.