Rapid CNC Machining Services

November 01, 2021

When designing a part for CNC machining, the first question one must ask is: what kind of CNC machine will be used for the part? RapidDirect uses a variety of machines, including standard mills, lathes and 5-axis machining centers, and these different machines are capable of creating different kinds of CNC machining parts.

Let’s look at a standard 3-axis vertical machining center as an example. When designing a part for 3-axis machining, one must consider the function of the machine: the cutting tool moves along three axes but always faces downwards, which naturally limits the kind of cuts the machine can make in the workpiece. If you create a diagonal cavity on the underside of the part, the machine will not be able to cut it unless the part is completely reoriented.

This is one of the most important factors to consider when designing CNC parts. If cuts need to be made on the reverse side of the part, the workpiece must be set up again the other way round. If it needs to be cut at a diagonal angle, it must be set up once more. These multiple setups take time and ultimately cost money, and it is therefore beneficial to design parts with features that face the same direction, reducing setup time.

5-axis machining centers, on the other hand, can cut the workpiece from a much greater number of angles, which therefore increases the engineer’s design freedom.

The cutting tool itself must also be considered. The cutting tool of a CNC mill, for example, has a cylindrical shape, and therefore cannot cut perfect right angles into a workpiece.