Die casting vs. metal injection – you probably have thought of the difference if you work in a manufacturing industry or perhaps have previously dealt with a manufacturing project. While these two techniques are essentially the same, they have advantages and limitations, making it critical to understand the difference.
If you still don’t know the difference or you have the quench to know which one is better than the other, you are in luck today – we are going to discuss the differences between die casting and injection molding techniques. From processes to material usage and selection, you’ll find a lot of information today. Continue reading to learn more.
Die Casting Vs. Injection Molding – A Comprehensive Comparison
What is Die Casting?
Die casting is a widely used manufacturing technique, known to be both extremely efficient and cost-effective. It is primarily utilized to produce everyday items with high-dimensional accuracy and strength. The process involves melting metal under high pressure. During die casting, the metal is melted and injected into an already-made mold to produce products like automotive parts, firearms, and more of the desired shapes and sizes.
The type of die-casting mold used can vary depending on each industry’s needs. Some industries may use steel or aluminum to produce parts. Other commonly used materials include magnesium and zinc.
What is Injection Molding?
In metal injection molding, this process utilizes powdered metal instead of molten metal. The powdered metal is carefully mixed with binder material with the intent of creating a feedstock. It is later solidified and shaped to produce the items of the desired shape.
After the completion of initial molding, the binder is taken out of the feedstock. After this step, all the metal particles are compressed as well as densified to attain the desired strength properties.
That Said, Here are Six Key Differences To Consider While Making a Choice
Processes
First things first – we’ll shed some light on die casting vs. Injection molding processes.
For die-casting, you as a manufacturer can use metal molds or dies to create metal parts.
This technique produces metal parts in many different ways. One great example is gravity permanent mold casting which involves pouring the molten metal into the die with the help of gravity. Some of the other common ways are high-pressure die casting and low-pressure die casting. These two use air pressure to inject molten metal into the die.
For metal injection molding, you need to use metal powder and thermoplastic binders. These are made of materials such as wax and polypropylene, which helps in the production of small intricate metallic parts.
Want to know other notable differences between die casting and injection molding? Let us tell you – the primary difference is what the processes rely on to inject the mold into the die. Die casting relies on gravity or pressure. Injection molding, on the other hand, relies on binding or, perhaps, the feedstock.
The feedstock is injected as a liquid injection into the injection molding machines, which then mold them into the exact shapes one desires. After the injection molding, the bindings must be removed from the mold, which calls for a sintering process. This helps remove the remaining binding without damaging the metal.
Precision and Tolerances
The range of tolerance for die casting can vary depending on the part’s complexity, type of material, and the manufacturing process. However, in general, die-casting has a tolerance range of +/- 0.005 inches to +/- 0.015 inches, and this requires the manufacturer to optimize the design or choose an alloy with a higher strength to improve tolerance and achieve precise and intricate parts.
Metal injection molding, on the other hand, is celebrated for its exact parts with tight tolerances. With this manufacturing technique, engineers can produce complex geometric shapes that seem impossible to achieve. This is because the powdered metal used is highly consistent in composition and particle size, thus reducing variability and inconsistencies in the finished product.
Material Differences
Die casting employs several metals in the manufacturing process, but the most commonly used are non-ferrous metals. These metals usually have low iron content, thus offering strength and durability, making them suitable for high-stress applications like automotive parts. The non-ferrous metals include magnesium, aluminum, and zinc alloys, all of which have their strengths and weaknesses in different applications.
On the other hand, metal injection molding materials lean towards finely powdered metals mixed with a binder material, usually made of plastic or wax. The binding material only acts intermediary, and it’s traditionally removed after molding, and the remaining metal is sintered.
Surface Finishing Options
Every manufacturing process isn’t complete until the final product has undergone surface finishing.
Die casting is known to create better-finished products than the metal injection molding technique. This is because components from metal injection molding usually emerge with a porous surface due to the removal of binders during sintering.
Components from die casting don’t need to undergo further surface finishes, but if they do, the typical surface finish options include anodizing, powder coating, impregnations, and so on. In injection molding, machining, sandblasting, or tumbling are some surface finish options manufacturers use to achieve the desired smoothness.
Applications
Metal injection molding finds its niche in crafting intricate small to medium-sized components that require high precision; thus, it is mainly utilized in most medical facilities and electronic industries to produce complex geometric shapes and electronic connectors.
Die casting, conversely, is suitable for producing more significant, structurally sound parts at high volumes. You will mainly find manufacturers from the automotive and aerospace industries opting for die casting since most of the components required are engine blocks and structural elements, which are usually large parts.
Tooling and Manufacturing Costs
Die casting and machining total costs are pretty high compared to injection molding. The reason is die casting requires the creation of intricate, durable molds usually made of steel which is more prone to erosion and losing acuity. This factor results in high tooling costs since manufacturers must adjust the design to achieve the perfect shape.
Injection molding, on the other hand, has lower manufacturing and tooling costs. Like die casting, the molds are made of steel or aluminum but with a focus on achieving smoother surfaces rather than extreme durability. Although injection molding has low, upfront costs, it may not be a cost-effective solution for those seeking to acquire durable metallic parts.
To reduce the upfront costs in both processes, industries can contact one of the best aluminum die casting manufacturers in China to deliver well-finished and high-quality components at affordable costs.
Die Casting Vs. Injection Molding- What Should You Pick?
Choosing between die casting vs. injection molding depends on your specific needs. If your goal is to produce sturdy high-volume components like automotive parts, die casting is an excellent option. However, if you wish to produce complex parts with tight tolerance, metal injection molding will make a perfect fit. Always consider factors such as material complexity and finishing options before making the final decision.