Food-grade stainless steel

Food-grade stainless steel is a safe metal for food preparation and water storage. As it cannot be die cast, many companies choose investment casting or machining, overlooking the advantages of metal injection moulding (MIM) for high-volume, complex stainless steel moulds.

Metal injection moulding for food-grade metals

When selecting a food-safe metal, customers often prioritise strength and corrosion resistance. Although aluminium, zinc, and copper can be used for food-safe components, they require post-casting coating to prevent leaching into food. Stainless steel, on the other hand, eliminates the need for coating or plating, reducing secondary operations and costs.

To ensure the safety of food and water, it is crucial to minimise residual metal and flash. MIM tools are designed to produce less flash through the use of stronger metals than die casting alloys, making post-production corrections more difficult.

Popular food-safe stainless steel

One of the most important aspects of food-grade stainless steel is its hygienic surface finish. It must be easy to clean and sanitise reliably. Otherwise, the surface may be susceptible to harmful bacterial growth—which is not compatible with FDA regulations.

Most food processing equipment is made from 304 or 316 austenitic stainless steels. While OptiMIM offers a variety of stainless steels for metal injection moulding, MIM-316L is most widely used for components that are safe for food and clean water. MIM-316L not only has high strength properties, but is also highly corrosion resistant—which is important for metals that come into contact with acids that break down and alter the alloy composition over time. The high alloy content and low carbon content of MIM-316L make it well suited to food-grade applications.

Use our metal selector tool to compare the mechanical and physical properties of other MIM alloys.

Designing for MIM

Metal injection moulding offers design freedom from the traditional constraints of shaping stainless steel. In addition to producing complex stainless steel parts in high volumes, MIM enables designers to mould parts with:

• Holes and slots
• Internal and external undercuts
• Threads
• Ribs and webs
• Knurling, lettering and logos

With metal injection moulding, you can achieve tighter tolerances by placing material only where it is needed for function and strength.  

For small, complex parts requiring high strength, corrosion resistance and food safety, consider consulting an OptiMIM design engineer to explore the MIM process and its advantages for food-grade applications.