Metal Injection Molding vs. Die Casting: Differences and Comparison |Echofast

Metal injection molding (MIM) and die casting are commonly used to allow high volume production of small metal parts in an economical way. Both processes suit most customers across a variety of industries, but they are different and have their own advantages and disadvantages. MIM is cost-effective for small, intricate and
high-volume products whereas die casting is well suited to larger parts. This article will review the basics of metal injection
molding and die casting, comparing the processes in depth.

What Is Metal Injection Molding?

Metal injection molding (MIM) is a metal working process where metal powder bound is injected to a thermoplastic binder to produce high-strength metal parts. The process adapts the technique of injection molding, but the MIM parts require additional processing steps to remove the binder and sinter the powder. It facilitates the production of small, complex-shaped metal parts with outstanding mechanical properties.

The Advantages of Metal Injection Molding Compared to Die Casting

The followings are some advantages of metal injection molding compared to die casting:

MIM can create many intricate parts in a single run.

Metal injection molding (MIM) can create high volumes of small and complex parts with fine features, which is more difficult for die casting.

MIM is also ideal for parts with thin wall specifications (i.e., 100 micrometers).

A wider range of materials using MIM are available than with die casting.

In the MIM process, high temperatures are only utilized during the sintering process. There is no requirement for a molten metal feedstock, which is indispensable for die casting instead. It is feasible to use materials with very high melting temperatures. In addition, processing and handling these metals in molten form are not required.

The Disadvantages of Metal Injection Molding Compared to Die Casting

Some disadvantages exist in injection molding when compared with blow molding:

Due to the abrasive nature of the metal powder feedstock, metal injection molded molds fail to last as long as diecast molds.

Multiple processing steps are required to produce the final part, which can lead to a higher cost.

There is a significant shrinkage among metal injection molded parts in the densification process. In the mold design, some factors should be taken into consideration, include the properties of the binder, the metal, and the interaction between the two during post-processing.This helps produce the final parts that can meet dimensional requirements.

Applications of Metal Injection Molding

Since metal injection molding can produce small parts with complex features and thin walls, it is used in a broad range of industries, including:

Firearms:

triggers, sights, safety, bolts, magazine catch, ejectors, fire suppression, fire control group components
Medical:

surgical instruments, articulation gears, joint replacement parts, drug delivery devices
Automotive:

turbocharger vanes, electrical connectors, rocker arms, system controllers, shift levers
Industrial:

micro gears, drone parts, machinery components
Aerospace:

rocket burners,valve holders, engine components, flap screws
Electronics:

lightning connectors, various mobile phone parts,smart wear,heat sinks, cold plates, cable accessories, and fiber optic parts

What Is Die Casting?

Die casting is a process for manufacturing metal parts that is characterized by injecting molten metal under high pressure into a mold. The final part can be ejected from the mold when it is allowed to tool.
Die casting is limited to non-ferrous metals, such as zinc, copper, aluminium, magnesium, lead, pewter, and tin-based alloys. Depending on the type of metal being cast, a hot- or cold-chamber machine is used.

The Advantages of Die Casting Compared to Metal Injection Molding

Listed below are some advantages of die casting compared to metal injection molding:

In general, die casting molds last longer than MIM molds.

Die casting parts do not shrink like MIM parts, making it more easy to manufacture the molds with the required size.

Die casting is less expensive than MIM due to the fewer production steps and the use of cheaper raw materials.

The cycle times for producing finished parts with die casting are typically faster than that of MIM when both the molding process and post-processing are taken into consideration.

The Disadvantages of Die Casting Compared to Metal Injection Molding

Some disadvantages exist in die casting compared to metal injection molding:

Die casting requires some post-processing clean-up to remove casting flash.

Die casting is typically used with non-ferrous metals, which leads to the limited use for high-performance and high-temperature applications.

Die casting parts have significantly more porosity than MIM parts, reducing the the parts' mechanical strength. This is because molten metal injected at high pressures and temperature often entraps gasses within the material.

Applications of Die Casting

Die casting can be used to create a wide variety of parts and products in different industries:

Automotive products:

gear, gearbox/differential housings,cylinders,major engine/motor components,vehicle wheels, interior strength members, etc.

Aerospace:

engines, seating, interior fitting, cockpit control, and more.

Electronics:

enclosures, heat sinks, hardware, antenna mounts, RF filters.

Medical:

surgical devices, peristaltic pumps, blood analysis machines.

Consumer and industrial products:

sink faucets, compressor pistons, connector rods, heat sinks, enclosures etc.

Differences Between Metal Injection Molding and Die Casting

Metal Injection Molding vs. Die Casting: Volume Comparison

Metal injection molding (MIM) and die casting are two processes for the production of high volumes of metal parts. MIM is ideal for the mass production of small parts with complex features, whereas die casting is better suited to high-volume production of larger, simpler parts.

Metal Injection Molding vs. Die Casting: Lead Cost Comparison

Metal injection molding is up to 30% more expensive than die casting because of the multiple post-processing steps.

Metal Injection Molding vs. Die Casting: Speed Comparison

Due to the requirement for post-molding processes, the overall cycle time to produce a finished part by metal injection molding is longer than for a finished diecast part.

Metal Injection Molding vs. Die Casting: Materials Comparison

Die casting is used almost exclusively for non-ferrous metals, including: aluminum, copper, zinc, magnesium, and lead. MIM allows for both non-ferrous metals and ferrous metals.