Die casting is one of the most flexible and innovative manufacturing techniques for fabricating metal parts. Several components for gears, locks, automobiles and motorcycle parts are manufactured with die casting. If you choose die casting process for your applications, it’s best to know its pros and cons beforehand.
In this article, you will learn in detail about die casting advantages and disadvantages. Also, we’d compare it to some other common manufacturing techniques to help you make the best choice.
What is Die Casting?
Die casting is a manufacturing process involving molten metals and alloys into a steel mold under extreme temperature and pressure conditions to create the desired shape. The die casting process is quite similar to that of plastic injection molding. However, it is mainly used for uses non-ferrous metals with low melting points and high fluidity, such as aluminum, zinc, copper, magnesium, etc.
There are of two types machines for die casting, the hot and cold chamber die casting machine.
A hot chamber cast machine features a built-in furnace that heats metal into a molten state before transferring it into molds for shaping, which can accelerate cycling production. In contrast, in cold chamber machine, heating metals takes place in a separate furnace.
Hot chamber machine casts metal alloys with low melting points like zinc, copper and lead. On the other hand, the cold chamber machine is preferred for high melting temperature metals and corrosion resistance. Therefore, the material you choose for the process determines which machine to use.
Die Casting Pros and Cons
After a brief understanding of the die casting process, let’s dive into its advantages and disadvantages. However, we first make a simple summary shown below.
|1||Provides high production efficiency.||The cost of the die may be expensive.|
|2||Allows easy production of thin-wall parts and internal components that require high precision standards.||Experience manufacturing difficulties when fabricating large parts.|
|3||Yields parts with a fine crystalline structure and excellent mechanical features.||Not ideal for ferrous metals and metal alloys with very high melting points.|
|4||Economical manufacturing process, especially for large volume production.||Prone to cause gas trappings, leading to the porosity of castings.|
|5||Low cost of post-processing operations because manufactured parts have good surface finishing.||The cycle production may take a long time, depending on the complexity of parts.|
5 Advantages of Die Casting Technology
1. Complex Thin-walled Parts
Aluminun die casting can manufacture complex-shaped and light components but with an excellent strength-to-weight ratio, giving it an edge over other metal molding castings and investment castings. Die casting parts with aluminum alloys can have a thickness as low as 0.5mm; the wall thickness of cast parts made with zinc can even be as low as 0.3mm.
2. High Mechanical Properties
Die casting products feature excellent mechanical properties. As the liquid metal solidifies under high pressure, the product appears to be fine, compact, and crystalline. Die casting parts are rigid with high hardness and strength. Also, they have improved durability and high conductivity.
3. High Dimensional Tolerance
Die casting produces parts with high durability and dimensional accuracy. Even when exposed to harsh conditions, the parts maintain their dimensional accuracy over time. As a result, die casting is used in fabricating complex and internal parts of machines that require high standards of precision and accuracy.
Die casting maintains tighter tolerances over other casting processes. That is, parts are produced with minimal variations. The typical tolerance class of die castings is IT13~IT15 in GB/T 1800-2009. Higher precision can reach IT10~W 11. Therefore, the excellent dimensional accuracy of die casting avoids the need for machining and improves the utilization of the alloy.
4. Smooth Surfaces
Die casting parts have a smooth, consistent crystalline surface. Die casting process alloys molten metal alloy to fill up the dies and create the exact shape. Therefore, provided the die is well shaped and the process is in the right condition, the parts will be fine and smooth.
Because of making glossy parts, there is less need to proceed with additional post-processing operations, except for custom needs. What’s more, after die casting is done, products can be shipped off for delivery. This can reduce the total cycle production time.
5. Cost-Effective for Mass Production
Since the surface of die castings is often smooth with excellent mechanical features, die-cast parts often require less machining. In some cases, no machining at all. As a result, there is less need to spend on secondary operations. The ability of die casting to reduce post-processing costs helps ensure its cost-effectiveness.
Notably, die casting machines, molds, and other related types of equipment are quite expensive. However, mass production aids in better distribution of cost through the production process, thereby making the die casting process economical.
5 Disadvantages of Die Casting Technology
1. Easily Generate Porosity
In the die casting process, molten metal rapidly fills the mold cavity at high speed, but the cavities lack gas permeability. Hence, gas bubbles that affect the structural integrity of fabricated parts tend to get trapped within castings.
The presence of gas cavities in die castings would affect such parts when exposed to harsh conditions, such as hardening by heat treatment. Additionally, such parts are predisposed to machining difficulties. Therefore, the machining allowance of the parts should be kept minimal. If not, the hardened layer on die casting surfaces would be removed, thereby exposing the surface.
2. Usually Support Non-ferrous Metals Only
Generally, die casting is perfect for non-ferrous metals with lower melting points than ferrous metal alloys. However, the process supports ferrous alloys like iron and steel. Ferrous metals have very high melting points and low corrosion resistance, which causes low die life. Therefore, manufacturers always choose non-ferrous metal alloys for die casting.
Moreover, casting ferrous metals come with lots of complexity and several unforeseen complications. Consequently, manufacturers stick to non-ferrous metals only for die casting operations.
3. Not Suitable for Low Volume Production
Die casting is not a practical choice for low volume production, because the tooling cost of die casting machines and maintenance are quite expensive. Therefore, the process is costly and seems complex for small-scale production.
However, large-scale production becomes cost-effective as costs are well distributed over the many items produced. Suppliers don’t recommend die casting services for low-scale projects, as the process appears to be more expensive than other production methods.
4. Low Die Life
High melting point metals and alloys compromise the effectiveness of steel dies. These metals, like copper, have extensive requirements to resist thermal deformation. The continued presence of alloys with high melting points strains the molding die, thereby reducing its durability.
5. Large Capital Investment
Unlike other casting processes, the casting machine, the dies, and other related equipment for die casting are costly. Without the essential equipment, it is impossible to carry out die casting. Although cheap materials like zinc are used to cut costs, the overall production process is still expensive. The only time die casting becomes cost-effective is in large volume production.
Die Casting Advantages: Comparing with Other Manufacturing Processes
We have discussed die casting pros and cons. Then, let’s compare die casting with other common manufacturing techniques, indicating why it is an important manufacturing process in industries.
Die Casting vs. Sand Casting
Making comparisons between die casting and sand casting, die casting proves to be a superior manufacturing process. The following are criteria where die casting proves to be a better technique than sand casting.
- Die casting requires less machining and other finishing operations.
- Die casting has better dimensional tolerances and greater production efficiency.
- Porosity is common to both die casting and sand casting. However, there are precautions to prevent it in die casting, but it is almost impossible in sand casting.
- Better surface properties.
- Requires less labor.
- Die casting uses a steel mold, the sand cast uses a sand mold.
- Sand casting is unsuitable for fabricating thin-walled components, whereas die casting is.
Die Casting vs. Injection Molding
Compared to plastic injection molding, die casting also seems to have an edge. Below are die casting advantages over injection molding.
- Products of die casting pose better mechanical properties. They are stronger, harder, tougher, and with greater thermal resistance.
- Die casting poses greater dimensional stability. Hence, more ideal for parts that require high precision and accuracy.
- Plastic products may be susceptible to ultraviolet radiation, unlike die castings.
- Die casting products are more durable and can better withstand stress, weathering, and heavy load situations.
- Die casting has a more rapid production cycle. Hence, manufacturers can manufacture large volumes of parts in a shorter duration.
Die Casting vs. Over Forging
Forging involves shaping metal under extreme compressive force. However, die casting proves superior to forging in the following:
- Die casting can better fabricate complex shapes and geometries.
- It has greater dimensional stability.
- Production of thin-walled components is a problem with forging.
- Tooling is cheaper in die casting.
Choose RapidDirect for Your Die Casting Parts
From this article, you probably now have a vast knowledge of die casting pros and cons. You know die casting is a top manufacturing process for high volume production and high dimensional accuracy parts.
Need a cost-effective die casting service? A reputable online die casting service provider – RapidDirect, is for you.
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Besides, we provide various solid materials that best suit your custom needs. Likewise, we provide several surface finishing options to help improve the features of the die casting parts. Also, we have experts and professionals that offer suggestions on how best to carry out your order.
What’s more, we have an online manufacturing quotation platform that allows you to get a quick and price-effective quotation for your die cast parts and free DfM analysis. You also get to monitor each production stage after placing orders on our digital platform.
Porosity is the major defect in die casting. Below are means of reducing porosity in die castings.
a. Maintain strict quality control measures during each production stage.
b. Use additives that will aid in releasing some of the dissolved gases when melting.
c. Lubricate the dies after each casting – this reduces porosity tendencies.
d. Try to create a vacuum inside the mold cavity during casting.
e. Design the mold properly for easy running and flow of the molten metal.
To minimize the tooling cost of die casting, the guidelines below should come in handy.
a. Try to simplify the design. Too many intricate details tend to increase the cost. Therefore, it is better to remove intricate details that are not critical for structural integrity and the part’s overall performance.
b. Though die casting can easily fabricate thin-walled components, reducing or avoiding them is better. Since these thin walls often require machining; hence they attract additional fabrication costs.
c. Desists from unnecessary tolerances. Too many precision requirements lead to an increased tooling cost.
d. Try to avoid features and undercuts that are difficult to access with a 3 or 4 axis CNC machine.
Metal injection molding (MIM) and die casting are similar manufacturing techniques. They both use metals and alloys in the fabrication of parts. The major difference is the metal types used in either method. Die casting uses mostly aluminum and other non-ferrous metals. In contrast, metal injection molding uses steel, iron, nickel, and other MIM alloys.