CNC Machining vs Injection Molding

CNC Machining vs. Injection Molding for Plastic Parts

Plastic parts are primarily created by CNC machining or injection molding. They are very different processes but each can produce high quality parts, depending on the desired outcome. Among the hundreds of plastic parts manufacturers in Wisconsin, at Dielectric Manufacturing, we focus on CNC machining.

We have a wide variety of CNC mills, lathes and panel saws that allow us to manufacture simple to complex parts, meeting high tolerances for mission-critical applications, such as those used in the defense and aerospace industries, medical equipment, and energy production.

What’s the difference between CNC machining and injection molding? In CNC machining, a computer-controlled machine tool removes material from a solid block of plastic, creating a high-precision part. Dielectric Manufacturing machines many different types of thermoplastic and thermoset materials, and we maintain a large stock of those plastics so we can readily machine parts. Injection molding, on the other hand, involves the melting of plastic pellets, and then injecting the melted material into a mold. Unlike injection molding, CNC machining also can produce metal parts.

CNC machining can be better suited to handle complex geometries in parts, producing intricate parts with high precision. The process is also suited to low- to medium-volume runs. For high-volume runs – especially for parts with simple geometries, injection molding is often the ideal solution, molding identical parts quickly and efficiently.

CNC machining does not require creation of a mold as is needed for injection molding, but there are start-up costs relating to programming and machine set-up. Creation of the injection molding mold can add to lead times for production.

So, in general, if you need parts where tight tolerances are essential, and if you need small to medium-size runs, CNC machining can be your best option.

Dielectric Manufacturing’s CNC equipment list includes 10 mills four lathes, four routers and four panel saws– each handled by highly skilled programmers and operators. See our Equipment page for a full list of our machines.