Metal Injection Molding vs Die Casting, What is difference?

Choosing between Metal Injection Molding and Die Casting is a highly situational decision. While one might seem a good option, the other can still shine its perks bright. Therefore, it is highly recommended to study the capabilities and limitations of both before you select either one. Especially when both processes have versatile yet specific applications.

Wondering how you’ll differentiate between Metal Injection Molding and Die Casting? Don’t worry, we have prepared a brief introduction of the processes to help you decide what’s best.

Metal Injection Molding (MIM)

MIM or Metal Injection Molding is a manufacturing process to produce complex metal parts in a single step. Although the process itself may contain two to three stages depending on the choice of the parent industry.

To get started, finely-powdered metal is combined with a binder material like but not limited to Wax or Thermoplastic Polymers. The mixture is thoroughly mixed to create a “feedstock” which, as the name suggests, is fed to an injection molding machine. Depending on the tonnage, the IM machine will inject the feedstock into a mold and it will solidify to its shape.

The solidified raw product is then sent for cleaning and debinding to make it a green body. This green body is heat-treated (sintered) to completely remove the binder material and a finished product is obtained.

Pros

• No material is waster
• Consistency in the products
• High tensile strength of finished products

Cons

• High running cost for large size products
• Requires skilled supervision

Die Casting

Die Casting is a go-to method for manufacturing non-ferrous metal parts but the production of ferrous parts is also possible. It is a relatively simple process; molten metal is inserted into a die with high pressure and is allowed to cool and ejected from the die afterward. This process can be explained in four words,

• Clamping – lubricating and then clamping the die shut.
• Injection – injecting molten metal into the die.
• Cooling – this stage begins as soon as the metal is injected but continues for a specific time.
• Ejection – the cast is removed from the die for removal of excess metal and trimming.

Depending on the type of metal to be used in the casting process, a hot or cold-cavity machine can be operated. Zinc, Aluminium, Copper, and Magnesium are the most common alloys used for Die Casting.

Pros

• Easy to operate
• Fully automatable
• Cost-effective
• Better mechanical properties

Cons

• Porosity in finished products
• Comparatively lower in quality
• Setup and replacement cost is high

What Is The Difference Between MIM and DC?

Now that you know what these processes are, it will be easier to understand their differences.

Since both processes excel in their relevant departments but are generically used to make parts, we have divided this difference section into some practical applications. Each of the following sections relates to the practicability of both Metal Injection Molding and Die Casting.

Here goes,

Wall Sizes

Product Wall Sizes are very important factors when complex, specific, and hollow tools are to be delivered. The Die Casting method gives you little to no control over the thickness and porosity of the walls of these tools which is why it cannot be used when thin walls are required for a product.

Metal Injection Molding, however, can work extremely well in this case since it can manufacture products by strictly following the set parameters.

Porosity

Metal Injection Molding produces a uniformly dense metal tool with high tensile strength thanks to the sintering process but Die Casting is comparatively weaker and more susceptible to have air pockets that make the structure weaker; commonly called porosity.

Product Dimensions

Metal Injection Molding produces dimensionally similar products as its focus is on quality and accuracy. However, Die Casting produce may contain varying product dimensions since most casts need to be trimmed to remove excess material.

Die Lifespan

In Die Casting, dies must withstand high pressure and melted-metal temperatures which may wear them out quickly. Despite this, dies can be used repeatedly and up to 1MM as compared to just 150K-330K shots for Metal Injection Metal.

Product Shrinkage

Metal Injection Molding industrialists must account for shrinkage accurately as sintering may reduce the volume of the product up to 30%. Die Casting does not have shrinkage as a major problem.

Running Costs

Die Casting is 20-30% cheaper than Metal Injection Molding. Although Metal Injection Molding can save metal from going to waste, it still needs a higher power supply, specialists to operate the equipment, and expensive raw material to make feedstock.

Automation and Product Design

Die Casting can be fully automated to reduce labor costs but cannot effectively deal with complex shapes and strict requirements. However, Metal Injection Molding provides full freedom of design and production of complex parts.

Feed Wastages

Metal Injection Molding has relatively no metal waste when compared to die casting because all the metal is injected into the die within set parameters. Die Casting involves injecting molten liquid metal to fill the die, any excess is later trimmed and wasted.

Note that some industries may recycle the trimmings but it still increases operational cost since more material must be handled.

Should You Prefer Metal Injection Molding over Die Casting?

This is a question that has both answers, yes and no.

The main reason for this is that it is highly dependent on the goal of your industry. If you want to manufacture some large tools or products, like gas engine chambers, containers, etc. then Die Casting should be your way forward.

Mainly because it is a relatively simple process and you won’t have trouble managing its expenses since the raw material is cheaper and easily available.

This situation changes when your goal is to produce complex designs of small tools or products. In this case, Die Casting cannot help you much, you can still produce the tools but there will be a lot of errors and every tool will have different parameters.

Metal Injection Molding can save both your time and resources in this kind of situation. Metal Injection Molding is proven to strict adherence of parameters which ensures that each tool is of the same dimensions and density.

It also reinforces the product by the sintering process. This not only improves the final quality of the tool but also eliminates any secondary stages. Ultimately, Metal Injection Molding crowns this situation.

Conclusion

Metal Injection Molding is a new and improved method of part manufacturing. However, it is still limited to being profitable only when larger runs of small detailed parts are required.

Die Casting is profitable for a variety of runs for less detailed larger parts. In case you’re still not able to decide, you can contact us and our experts will help you decide.