Injection molding is a plastic fabrication process that involves injecting a molten plastic polymer into a pre-designed mold. The mold is designed based on the desired product and comes from several materials. In part manufacturing, the two commonest materials used in making molds are aluminum and steel.
Aluminum injection molds are applicable in several part manufacturing industries due to features such as the ability to dissipate heat fast. This article introduces aluminum injection molds, a comparison with steel injection molds, and their application in part manufacturing.
Concept: What is Aluminum Injection Molding?
Aluminum injection molding is an injection molding process that involves using an aluminum mold. It is an innovative technique applicable in several industries due to its consistency, accuracy, and machinability, which aids in producing complex product designs. Furthermore, the mold has a high heat dissipation, which makes it able to effectively transfer heat from the molten plastic outside and aids in quick product formation.
Advantages of Aluminum Injection Molds
Aluminum injection molds are applicable in several plastic fabrications due to the following advantages.
1. Cost
Using aluminum to make an injection mold is less costly than using steel. Although this depends on the grade of aluminum used, you can still save up to 30% of the cost with aluminum. However, the overall worth and return on investment depend on its use.
2. Lead time
Designing an aluminum injection mold is faster than steel injection molds can take weeks. In contrast, aluminum mold takes days. Therefore, it has a faster lead time in making the required prototypes and final products.
3. Heat Dissipation
Aluminum injection molds have high heat dissipation, i.e., they can heat and cool very faster. As a result, the manufacturing process is faster. Part manufacturing processes favor the molds for the fast and low-volume production process.
4. Better Products
Aluminum injection mold’s excellent heat dissipation also reduces the occurrence of defects such as sink marks, voids, and burn scars. This is unlike other materials, which sometimes have non-uniform heat dissipation leading to defective parts and rejects.
5. Easy Repair and Modification
Aluminum injection mold comes from aluminum which is a soft material. Therefore, it is easier to repair and modify. Furthermore, this reduces the cost of maintenance
Injection Molding: Aluminum vs. Steel Tooling
Aluminum and steel injection molds are the most common material used for making injection molds used in automotive, aviation, and other industries. Both types of molds have features and characteristics that aid their different applications. Here is a comparison between aluminum injection mold and steel plastic injection mold.
Flexibility
Aluminum is a soft material. As a result, machining the material to form the injection mold is easier. Furthermore, ease in machining increases the flexibility of the part manufacturer during product design. For example, it is possible to produce the mold part separately.
On the other hand, steel injection molds come from a hard material further subjected to heat treatment. Due to the hardness, machinability requires sophisticated equipment leading to lesser flexibility in the design process to save cost.
Endnote: aluminum injection molds are perfect for making prototypes or real parts that require on-the-spot adjustment.
Product Design Complexity
Steel molds are more suitable for making parts with complex product designs. A complex product design will likely have thin sections and thick sections. Therefore, there is a need for a material that is structurally strong to allow such parameters and cope with the process’s high pressure and temperature without deformation. Aluminum injection molds are unsuitable because they will likely deform under this condition.
Note: Product design complexity should not be confused with flexibility.
Surface Finish Options
Steel injection molds have high density, which allows more texture selection. This is because inserts make it easier to add details to the mold. On the other hand, the number of optional surface finishes in aluminum molds is lower.
Flash Problem
Injection molding flash occurs when the plastic polymer seeps into the mold seams during the injection process. Although they are removable during post-processing, it can increase the process’s cost. Aluminum molds are soft and may deform. Therefore, they are more prone to flash.
Handling Aggressive Materials
Aggressive plastic polymers such as ASA and glass-filled nylon can reduce an injection mold lifespan due to the need for high temperature and pressure during injection. Therefore, there the right mold should be capable of handling such materials.
Steel injection molds are suitable for all plastic polymers due to their hardness and heat treatment. On the other hand, aluminum plastic injection molds do not undergo further thermal processing and won’t be able to handle the high injection pressure and temperature of the materials needed.
Mold Turnaround Time
Aluminum plastic injection molds are manufactured using CNC machining or Electrical Discharge Machining (for molds with sharp corners). Due to their softness, they don’t require special equipment or additional processing. Therefore, making one just takes about a few days.
On the other hand, steel injection molds are made using CNC machining. However, due to their hardness, the machining has a few requirements that make the process longer. Furthermore, it undergoes heat treatment to increase its lifespan, increasing the turnaround time.
Mold Robustness
Mold robustness is a term that denotes the capability of mold before it reaches the end of its lifespan. This depends on the mold’s genetic makeup and design.
On the one hand, steel injection molds come from a hard material and undergo heat treatment. As a result, they are very rigid and durable and can produce millions of parts before they wear out. On the other hand, in comparison, aluminum injection molds come from soft aluminum and don’t undergo any extra thermal processing. Hence, they are only strong enough for thousands of parts before they wear out.
Production Time
Production time is when it takes to inject the polymer, cool off, and eject it. It depends on the mold, temperature, and pressure. On the one hand, aluminum molds are only suitable for working at a regulated pressure and can dissipate heat faster due to their nature. Therefore, they have a shorter production time.
When Should You Choose Aluminum Injection Molds?
Choosing between aluminum and injection molds depends on what you need. Below are a few scenarios you should consider.
Number of Parts
Aluminum injection molds are better if you want to make fewer parts. This is because the mold has mold robustness of about 10,000 to 100,000 parts.
Need for Revision
Aluminum mold design should include the need for revisions for proper adjustment. While it is possible to revise the mold after machining, it most time involves sacrificing the tool. However, the process will increase the aluminum injection mold cost.
Rapid Prototyping
Aluminum molds are the better option for rapid tooling because of the flexibility in design, ease of revising designs, and the support for low production volume. Aside from that, there is a balance between tooling costs and injection molding.
Challenges and Tips of Aluminum Injection Molding
Using aluminum injection molds comes with its challenges. Here are a few challenges you might face with the process and how to solve them.
Mold Durability
Aluminum molds are less durable, corrosion resistant, and wear resistant than steel molds. Therefore, they are less suitable for large volume production.
You can improve the durability via the following:
-Use Inserts: Inserts have different shapes and materials and can help increase the mold’s durability and surface hardness.
-Annealing: Annealing is a heat treatment that helps increase mold durability. However, it will also increase the aluminum injection molding cost
Uniform Heat Dissipation
Thin sections cool and solidify quicker than thick sections. However, thick sections can act as a reservoir of heat that feeds the thinner section for uniform cooling. Therefore, you should ensure that the mold feed path will allow uniform cooling by using uniform wall thickness. Furthermore, you can plate with an element such as silicon that can retain heat than aluminum.
Cracking and Other Defects
Cracking and other deformities due to uneven shrinkage during the cooling process result from sharp corners. Therefore, you can introduce fillets in the mold design instead of sharp corners.
Conclusion
Aluminum injection molding is a series of manufacturing techniques used in making molds from aluminum. The aluminum plastic injection molds are one of the common aluminum toolings and don’t undergo any heat treatment procedure during the design stage.
Do you desire a quality injection molded product at a competitive price? Let WayKen help you with your rapid tooling molds. With advanced machining technology and an experienced team, we can produce high-quality and cost-effective fast molds for your project. Whether your injection molding application is in the automotive, aerospace, medical, or electronics industries, our aluminum and steel mold services can help you.
Upload your CAD files and get an instant quote for your design.
FAQs
How long can aluminum injection molds last?
The lifespan of an aluminum injection mold depends on its use. For example, mold can produce thousands of parts when used in a low-volume product. However, for large volume manufacturing, the lifespan will reduce. You can also use surface coating techniques such as anodizing to improve the durability and lifespan.
Can aluminum be injection molded?
No, only plastic polymers and resins can undergo injection molding. Metals such as aluminum cannot. Instead, they can undergo die casting, sand casting, and other casting processes.
What common type of aluminum is used for aluminum mold?
7050 aluminum is the most common for making aluminum mold used in blow molding and injection molding. It is applicable due to its toughness, strength, and stress corrosion cracking resistance. Another common aluminum alloy is the 6061 aluminum alloy also known for its corrosion, stress, and cracking resistance.
Injection molding is a plastic fabrication process that involves injecting a molten plastic polymer into a pre-designed mold. The mold is designed based on the desired product and comes from several materials. In part manufacturing, the two commonest materials used in making molds are aluminum and steel.
Aluminum injection molds are applicable in several part manufacturing industries due to features such as the ability to dissipate heat fast. This article introduces aluminum injection molds, a comparison with steel injection molds, and their application in part manufacturing.
Concept: What is Aluminum Injection Molding?
Aluminum injection molding is an injection molding process that involves using an aluminum mold. It is an innovative technique applicable in several industries due to its consistency, accuracy, and machinability, which aids in producing complex product designs. Furthermore, the mold has a high heat dissipation, which makes it able to effectively transfer heat from the molten plastic outside and aids in quick product formation.
Advantages of Aluminum Injection Molds
Aluminum injection molds are applicable in several plastic fabrications due to the following advantages.
1. Cost
Using aluminum to make an injection mold is less costly than using steel. Although this depends on the grade of aluminum used, you can still save up to 30% of the cost with aluminum. However, the overall worth and return on investment depend on its use.
2. Lead time
Designing an aluminum injection mold is faster than steel injection molds can take weeks. In contrast, aluminum mold takes days. Therefore, it has a faster lead time in making the required prototypes and final products.
3. Heat Dissipation
Aluminum injection molds have high heat dissipation, i.e., they can heat and cool very faster. As a result, the manufacturing process is faster. Part manufacturing processes favor the molds for the fast and low-volume production process.
4. Better Products
Aluminum injection mold’s excellent heat dissipation also reduces the occurrence of defects such as sink marks, voids, and burn scars. This is unlike other materials, which sometimes have non-uniform heat dissipation leading to defective parts and rejects.
5. Easy Repair and Modification
Aluminum injection mold comes from aluminum which is a soft material. Therefore, it is easier to repair and modify. Furthermore, this reduces the cost of maintenance
Injection Molding: Aluminum vs. Steel Tooling
Aluminum and steel injection molds are the most common material used for making injection molds used in automotive, aviation, and other industries. Both types of molds have features and characteristics that aid their different applications. Here is a comparison between aluminum injection mold and steel plastic injection mold.
Flexibility
Aluminum is a soft material. As a result, machining the material to form the injection mold is easier. Furthermore, ease in machining increases the flexibility of the part manufacturer during product design. For example, it is possible to produce the mold part separately.
On the other hand, steel injection molds come from a hard material further subjected to heat treatment. Due to the hardness, machinability requires sophisticated equipment leading to lesser flexibility in the design process to save cost.
Endnote: aluminum injection molds are perfect for making prototypes or real parts that require on-the-spot adjustment.
Product Design Complexity
Steel molds are more suitable for making parts with complex product designs. A complex product design will likely have thin sections and thick sections. Therefore, there is a need for a material that is structurally strong to allow such parameters and cope with the process’s high pressure and temperature without deformation. Aluminum injection molds are unsuitable because they will likely deform under this condition.
Note: Product design complexity should not be confused with flexibility.
Surface Finish Options
Steel injection molds have high density, which allows more texture selection. This is because inserts make it easier to add details to the mold. On the other hand, the number of optional surface finishes in aluminum molds is lower.
Flash Problem
Injection molding flash occurs when the plastic polymer seeps into the mold seams during the injection process. Although they are removable during post-processing, it can increase the process’s cost. Aluminum molds are soft and may deform. Therefore, they are more prone to flash.
Handling Aggressive Materials
Aggressive plastic polymers such as ASA and glass-filled nylon can reduce an injection mold lifespan due to the need for high temperature and pressure during injection. Therefore, there the right mold should be capable of handling such materials.
Steel injection molds are suitable for all plastic polymers due to their hardness and heat treatment. On the other hand, aluminum plastic injection molds do not undergo further thermal processing and won’t be able to handle the high injection pressure and temperature of the materials needed.
Mold Turnaround Time
Aluminum plastic injection molds are manufactured using CNC machining or Electrical Discharge Machining (for molds with sharp corners). Due to their softness, they don’t require special equipment or additional processing. Therefore, making one just takes about a few days.
On the other hand, steel injection molds are made using CNC machining. However, due to their hardness, the machining has a few requirements that make the process longer. Furthermore, it undergoes heat treatment to increase its lifespan, increasing the turnaround time.
Mold Robustness
Mold robustness is a term that denotes the capability of mold before it reaches the end of its lifespan. This depends on the mold’s genetic makeup and design.
On the one hand, steel injection molds come from a hard material and undergo heat treatment. As a result, they are very rigid and durable and can produce millions of parts before they wear out. On the other hand, in comparison, aluminum injection molds come from soft aluminum and don’t undergo any extra thermal processing. Hence, they are only strong enough for thousands of parts before they wear out.
Production Time
Production time is when it takes to inject the polymer, cool off, and eject it. It depends on the mold, temperature, and pressure. On the one hand, aluminum molds are only suitable for working at a regulated pressure and can dissipate heat faster due to their nature. Therefore, they have a shorter production time.
When Should You Choose Aluminum Injection Molds?
Choosing between aluminum and injection molds depends on what you need. Below are a few scenarios you should consider.
Number of Parts
Aluminum injection molds are better if you want to make fewer parts. This is because the mold has mold robustness of about 10,000 to 100,000 parts.
Need for Revision
Aluminum mold design should include the need for revisions for proper adjustment. While it is possible to revise the mold after machining, it most time involves sacrificing the tool. However, the process will increase the aluminum injection mold cost.
Rapid Prototyping
Aluminum molds are the better option for rapid tooling because of the flexibility in design, ease of revising designs, and the support for low production volume. Aside from that, there is a balance between tooling costs and injection molding.
Challenges and Tips of Aluminum Injection Molding
Using aluminum injection molds comes with its challenges. Here are a few challenges you might face with the process and how to solve them.
Mold Durability
Aluminum molds are less durable, corrosion resistant, and wear resistant than steel molds. Therefore, they are less suitable for large volume production.
You can improve the durability via the following:
–Use Inserts: Inserts have different shapes and materials and can help increase the mold’s durability and surface hardness.
–Annealing: Annealing is a heat treatment that helps increase mold durability. However, it will also increase the aluminum injection molding cost
Uniform Heat Dissipation
Thin sections cool and solidify quicker than thick sections. However, thick sections can act as a reservoir of heat that feeds the thinner section for uniform cooling. Therefore, you should ensure that the mold feed path will allow uniform cooling by using uniform wall thickness. Furthermore, you can plate with an element such as silicon that can retain heat than aluminum.
Cracking and Other Defects
Cracking and other deformities due to uneven shrinkage during the cooling process result from sharp corners. Therefore, you can introduce fillets in the mold design instead of sharp corners.
Conclusion
Aluminum injection molding is a series of manufacturing techniques used in making molds from aluminum. The aluminum plastic injection molds are one of the common aluminum toolings and don’t undergo any heat treatment procedure during the design stage.
Do you desire a quality injection molded product at a competitive price? Let WayKen help you with your rapid tooling molds. With advanced machining technology and an experienced team, we can produce high-quality and cost-effective fast molds for your project. Whether your injection molding application is in the automotive, aerospace, medical, or electronics industries, our aluminum and steel mold services can help you.
Upload your CAD files and get an instant quote for your design.
FAQs
How long can aluminum injection molds last?
The lifespan of an aluminum injection mold depends on its use. For example, mold can produce thousands of parts when used in a low-volume product. However, for large volume manufacturing, the lifespan will reduce. You can also use surface coating techniques such as anodizing to improve the durability and lifespan.
Can aluminum be injection molded?
No, only plastic polymers and resins can undergo injection molding. Metals such as aluminum cannot. Instead, they can undergo die casting, sand casting, and other casting processes.
What common type of aluminum is used for aluminum mold?
7050 aluminum is the most common for making aluminum mold used in blow molding and injection molding. It is applicable due to its toughness, strength, and stress corrosion cracking resistance. Another common aluminum alloy is the 6061 aluminum alloy also known for its corrosion, stress, and cracking resistance.
