In de past decade, 3D printing became a very popular manufacturing technique. More specific, Before you had plastic injection molding (among different kinds of molding) and CNC machining of plastic parts. Nowadays, we have to ask ourselves: is plastic CNC machining a good alternative to 3D printing?
Obviously 3D printing found its way in many industrial and even medical applications. It has to be said, that its popularity grew in niche markets where single pieces and low volumes are required. To clarify, 3D printing is very popular for prototyping and medical prothesis, for example.
CNC machining has some advantages over 3D printing.
Nevertheless, when it comes to fabrication of functional parts with certain specifications such as strength, chemical resistance or small series fabrication, the obvious choice is still CNC machining of plastic components. Even, CNC machined plastic prototypes have benefits compared to their 3D printed counterparts. Often, the machined plastic components are stronger in different directions. The reason is that with 3D printing the strength is determined by the direction of the layers. Next, we use specific materials such as ABS, PA66, POM and PEEK for CNC machining. Where in 3D printing the material options are rather limited.
Plastic CNC machining is faster than 3D printing, when more than 1 copy is required. Let’s say that above 10 pieces you should really consider CNC machining. Even in terms of cost you are then better of with machining. Because the time of 3D printing won’t change much between 1 and 10 pieces.
While the minimum wall thickness of CNC machined plastic parts is about the same as most 3D printing techniques, it must be said that we obtain tighter tolerances with CNC machining.
A disadvantage of CNC machining is that there are limitations to the complexity of the design. Parts designed for 3D printing have a lot less limitations. More specific, it is possible to obtain very complex shapes. It is even possible to print hollow parts in 3D. When designing parts for CNC machining, you better consider the restrictions of the CNC machine and its rotating cutting tools. But nevertheless, with modern machinery we fabricate plastic parts with complex curved surfaces as well. Therefore, we use ball head mills.