Choose Aluminum Injection Molding for Rapid Low-Volume Manufacturing

Aluminum injection molds, custom plastic parts, Low-Volume Manufacturing, Rapid Injection Molding

Plastic injection molding is a technique using steel molds to mass batch production of plastic products. Aluminum injection molding is a technology that uses a mold made of aluminum for injection molding.

Steel molds are widely used in plastic materials, product design is more flexible, and the products produced are stable and durable. When we need to manufacture the same plastic products in large quantities, choosing steel molds is undoubtedly the best choice. But if a newly constructed product has not been tested by the market, blind mass production will generate huge waste and losses. Moreover, the steel mold manufacturing cycle is long, and production lead time cannot be guaranteed, which is very unfavorable for the development of new products. Therefore, in order to seek a simpler mold process, lower cost production, and get the product faster, injection molding manufacturers tend to use aluminum injection molding.

In this article, we will discuss aluminum injection molding and their advantages, disadvantages and situations where they are suitable.
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Advantages of Aluminum Injection Molding

Aluminum injection molding is an advanced manufacturing process that offers several advantages:

Low cost

Aluminum injection molding has a lower cost than steel injection molding. Aluminum is a relatively cheap material, making aluminium injection moulds cost lower than steel molds. Moreover, the processing of aluminum is simpler than that of steel, and the processing cost is lower.

Fast production Lead time

Aluminum injection molding has a short processing time. Aluminum is easier to machine than steel. Whether it is CNC machining or electric discharge and other processing methods, the aluminum mold will be faster. When the aluminum plastic injection mold is quickly made, it can be put into injection molding production, and then plastic products are obtained. A simple aluminum mold can be completed in 10 days, but the time for a steel mold will be more than twice that of making an aluminum mold.

Good surface quality products

The surface quality of aluminium injection molding is very good, and the surface of the injection molded parts is smooth and flat, so no additional surface treatment is required. This also saves costs and time.

Suitable for small batch production

For small-batch production of parts, aluminum plastic injection mold is a more suitable manufacturing method. If steel mold injection molding is adopted, it will undoubtedly require more time and manufacturing costs. Considering economic benefit is what we must pay attention to. Aluminum injection moulding is ideal for producing thousands of reliable parts with low upfront costs.

Ease of modification

Compared with other types of molds, aluminum molds are easy to modify, so if the design needs to be changed, it can be quickly modified and iterated, thereby shortening the development cycle.
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Disadvantages of Aluminum Injection Molding

Relatively short mold life

Aluminum injection molding generally has a shorter life than steel molding due to the lower strength and hardness of the aluminum material, which is susceptible to factors such as wear and fatigue.

Not suitable for high-volume production

Due to the relatively short life of aluminum molding, the number of products that can be produced is limited, so it is only suitable for small-scale production. Frequent changing of aluminum molds for high-volume production obviously complicates the manufacturing process. Therefore, aluminum injection molding is usually suitable for small batch production or sample making, and for large-scale production and high-precision production, other molding methods may be more suitable.

Design limitations

The design of aluminum molding is limited by materials and manufacturing technology, so it may not be possible to realize the production of some complex or specially shaped parts. In addition, the size and precision of aluminum molding are also limited, which cannot meet the production needs of some high-precision or large-size parts.

Low reliability

The reliability of aluminum molding is relatively low. Due to the low hardness and strength of aluminum mold materials, problems such as deformation or wear are prone to occur, which will lead to unstable quality or a high defect rate of molded products.

Situation applications for aluminum mold injection molding

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Aluminum injection molding is a very flexible injection molding method. Since aluminum is easy to process and the price is relatively cheap, it is easier to adjust both in terms of time and process.

Small batch production

The time and cost required to manufacture aluminum molds is lower than other types of molds (such as steel molds), so for small batch production, injection molding with aluminum molds can be more cost-effective.

Rapid production

The production cycle of aluminum mold injection molding is relatively short, much less than the processing time of steel molds. Therefore, aluminum mold injection molding is very suitable for situations where samples need to be produced quickly for testing and verification, so as to verify the feasibility of new product designs quickly.

Precision parts

Aluminum injection molding can manufacture precision parts, can realize high-precision dimensional control and surface quality control, and can meet the manufacturing of high-precision parts. It can meet some application fields that require high precision, such as automotive, electronics, medical, aviation and other fields.

Products with high-quality surface

The surface of products produced by aluminum injection molding is flat, smooth, and without obvious defects, which is very suitable for the production of products that require high-quality surfaces, such as mirror products, optical devices, etc.

Manufacturing Process of Aluminum Mold

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Injection aluminum mould is a tool used to produce plastic products, it is usually made of aluminum alloy. The manufacturing steps of injection aluminum molds are similar to those of steel molds, except that the processing of aluminum materials is simpler and more efficient.

  • Mold Design and Drafting: The design of the injection aluminum mold needs to be worked out first to ensure that it conforms to the required size and shape. This step can be done using CAD (Computer Aided Design) software.
  • Manufacturing aluminum molds: According to design drawings, aluminum alloys are used to manufacture injection molds. Usually need to use machine tools, such as CNC machine tools, wire cutting machines, polishing machines, etc.
  • Mold surface treatment: Surface treatment such as polishing and electroplating is carried out on the surface of the mold to improve the wear resistance and surface quality of the mold.
  • Assemble the mold: Assemble the various parts of the mold to ensure that the mold can be used normally.
  • Testing and modification: testing and debugging of the newly manufactured injection molded aluminum to ensure that it can be used normally and meets the required production requirements. If it needs to be modified, it needs to be processed and debugged again.

The above are the manufacturing process steps of the aluminum injection mold. The manufacture of aluminum plastic injection molds requires a very precise machining and assembly process to ensure that they function properly and produce high-quality plastic products.

Aluminum Injection molds and Steel injection Molds

Traditional injection molding relies on steel injection molds to produce large numbers of parts. However, steel molds have certain limitations. Therefore, there is a need for an alternative process, such as the aluminum forming process. Injection steel molds are generally more expensive than aluminum molds because they require more material and more complex machining. In low-volume production, aluminum tooling can be more reasonable in cost and can be replaced more easily when needed.


The flexibility of aluminum molds is manifested in many aspects. Since aluminum is softer than steel, the processing difficulty coefficient is low, which makes the product design more flexible, and it is easier to implement the modification and replacement of the corresponding aluminum mold. On the other hand, the manufacturing cost of aluminum molds is low, and batch aluminum mold injection molding usually requires less investment, and it is easier to customize and flexibly adjust production of plastic products.

Mold production lead time

aluminum plastic injection mold is made of aluminum material through CNC processing technology. Sometimes, when a cavity must have sharp corners, manufacturers use electrical discharge machining (EDM). However, a typical aluminum cavity takes about 10-15 days. Injection steel mold fabrication usually requires longer fabrication time due to the rigidity and hardness of steel. In order to have a longer service life, special manufacturing equipment is usually required for heat treatment, nitriding treatment, etc. of the mold. A typical steel mold takes about 30 days or several months.

Mold life

Injection steel molds are generally stronger and more durable than aluminum molds, so they will be more reliable when producing high volumes. The aluminum mold has a shorter service life because the aluminum material is softer and more prone to wear. But in small batch production, due to the small demand for products, the durability of aluminum molds is usually sufficient to meet the demand.

To sum up, the choice of injection molding steel mold or aluminum mold depends on many factors such as the scale of plastic products produced, the durability and reliability required by the mold, the production cycle, and manufacturing costs. Product developers and investors should choose according to their own situation to choose.

For example, an auto parts company needs to manufacture a small batch of automotive plastic parts. Due to the low volume, the company decided to use aluminum molds for injection molding production. However, during the production process, the aluminum mold is quickly worn out, resulting in reduced production efficiency and increased costs. At the same time, the market has a greater demand for products, and the service life of aluminum molds cannot be satisfied. In the end, the company decided to use steel molds for production. Although steel molds cost more to manufacture, they have a longer lifespan and can produce dozens or even millions of injection molding parts, which can better meet the needs of the company and the market.

Custom Aluminum Molds

Aluminum molds and injection molds have their own disadvantages and advantages. It needs to be selected according to different product production requirements. With the subdivision of products in the market and the diversity of people’s needs, custom small batch aluminium injection molding is favored by more developers, and the prospect of rapid aluminum molds is becoming broader and broader.

If you need custom rapid injection molding and need aluminium mold for plastic injection, Sungplastic will be your great partner. Sungplastic is an aluminum mold maker of auto parts and electronic parts with many years of manufacturing experience. If you already have a CAD file or 3D drawing, please consult us for prompt manufacturing advice.

About Sungplastic

About Sungplastic

Sungplastic is a plastic product manufacturer with rich experience in injection molding. According to the different product development requirements, we flexibly adjust the manufacturing process to achieve high quality, high efficiency and more economical.

We offer a variety of manufacturing services: Rapid Prototyping, Tool Making, Injection Molding, Product Design and Development, CNC Machining and Metal Stamping. You can choose from a variety of plastics, silicone rubber, or metal for your product. Regardless of mass production or small batch customization, Sungplastic has always been committed to providing assured, efficient and more economical one-stop processing services for your projects.

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