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 non-castable parts.

Differences between metal injection moulding and machining

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

Unique geometry

MIM offers unique geometry and complexity capabilities. Machining provides limited intricacy, flexibility and design freedom, and it is often more difficult to machine complex components. As components become more complex, MIM becomes more cost-effective because more complex parts require more machine time to produce.

Strength & performance

While both processes yield strong parts, MIM components do not undergo 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.

Mould investment

When creating a MIM component, the complexity of the part is usually tied to the mould investment. This means that the mould or tool itself is complex, so there is 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. With the MIM process, you do not have to spend funds 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 increase from 10k parts a week to 20k, you have to buy more CNC machines to reach capacity. With MIM, you do not have to do that.

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 operations. When applied appropriately, MIM can significantly decrease 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.