MIM vs machining

Metal injection moulding is a process that combines plastic injection moulding and powder metallurgy. It produces precise, complex metal parts, including stainless steel and other low-alloy steels, often in large quantities. Machining, which removes unwanted material from a metal block, offers similar alloy options but may be less cost-effective for complex parts. Before MIM, machining was the primary option for parts that could not be cast.

Differences between metal injection moulding and machining

In terms of similarities, MIM components compare well with machined parts as finished components. Typically, MIM components can be used in the same applications as machined parts—aerospace, medical and firearms—and in some cases, MIM parts look very similar to machined parts. However, metal injection moulding offers advantages for precision components that machining cannot provide.

Unique geometry

MIM offers unique geometry and complexity capabilities. Machining provides limited intricacy, flexibility and design freedom, and complex components are often harder to machine. As components become more complex, MIM becomes more cost-effective because the more complex your part, the more machine time it will take to produce.

Strength & performance

While both processes yield strong parts, MIM components do not endure machine-induced stress or internal pressure, which may result in deformation over time and potential part failure. MIM parts are moulded using conventional moulding machines and then placed in an oven, where the wax is strategically melted from the component, leaving a strong, solid component.

Tooling investment

When creating a MIM component, the complexity of the part is usually tied to the tooling investment. This means that the mould or tool itself is complex, so you have one upfront cost tied to the complexity of your component. With machining, adding complexity adds extra cost and process time to the part price.

Material scrap

Material scrap is not wasted in the MIM process. This is important because, as a customer sourcing a machined part, you are paying for that scrap. Through the MIM process, you do not have to spend money that could be used elsewhere.

Capacity

MIM is more scalable when ramping up capacity. Machining takes a considerable amount of time to produce complex parts, so if you want to go from 10k parts a week to 20k, you have to buy more CNC machines to increase capacity. With MIM, you do not need to do so.

Other metal injection moulding benefits

When you use the MIM process, you also gain:

• Repeatability
• Improved cycle time
• Part consolidation
• Reduced need for secondary operations

Why choose MIM over machining?

MIM becomes a more cost-effective alternative to machining for some applications when you consider the volume and complexity of your project. MIM produces complex, net-shape components that require no secondary machining. When applied appropriately, MIM can significantly reduce costs associated with secondary overhead while increasing production rates.

Our team of engineers offers design solutions for a variety of industries, including consumer electronics, automotive, healthcare and more. When our engineers are involved early in the project, they can help design a tool and part specifically for mass production. Contact our team today to get started on your next project.