Advantages of Rapid Injection Molding for Prototyping

Of course, even if rapid injection molding were able to be used for prototyping, despite the modifications, making the mold would still be a long and complicated process. For example, 3D printing a part takes 2 to 5 days instead of weeks. So why use rapid injection molding? The rapid injection molding process offers many advantages over other prototyping techniques.

1. Strength and surface treatment of rapid injection molding

Rapid injection molding is designed for manufacturability to ensure optimal injection angles and uniform wall thickness, and the liquefied resin is injected into the cavity under high pressure. It ensures that the parts are void-free and that the quality of the final material is the best. Such a thing cannot be said for 3D printing that uses powder or fine wire and sinters them together. As a result, the final material may have pores or unsintered regions. The surface finish of rapid injection molding parts depends on the quality of the mold. Pockets are usually CNC milled, followed by some finishing operations. The most common of these is polishing. Additionally, EDM cuts are used to sharpen the inside corners of the cavity. The final surface finish can be as small as Ra 0.8 μm.

2. Excellent precision and materials for rapid injection molding

Injection molding offers higher precision than other prototyping techniques. For example, 3D printing can only produce IT9 at most, while rapid injection molding is only limited by the accuracy of the mold, which can be as high as IT7.

Many prototyping techniques do not consider materials at all. It's okay when you're producing single-digit batches. However, some products require extensive testing under real-world conditions. For example, medical prototypes, their final testing phase involves distributing the product to consumers for everyday testing. This means you will need hundreds or even thousands of samples, and losing 50% or more of your blank material will cost you a fortune. Rapid injection molding now injects only the required amount of plastic into the cavity, minimizing waste.

3. Rapid injection molding molds can be used for mass production

Most prototyping processes are good at creating small numbers of parts. For example, silicone castings can be used for up to 15 or so parts. After that, the form of the casting deteriorates too much and you need another form of manufacture. Rapid injection moulding moulds are not as durable as traditional moulds, but they can still withstand more runs than most prototyping processes. The best of them can make up to 100,000 parts before they become too worn.