Understanding How CNC Machines Make Parts

CNC machine shop in Hillsboro

As a CNC machine shop in Hillsboro, our team at API/AMS understands that not everyone is familiar with how our business operates. Complex terms like precision machining and CAD/CAM design can seem like so much technical talk for the uninitiated. To help our customers gain a better understanding of what we do, here’s handy decoder ring you can use to decipher some of our services.

What is CNC?

CNC stand for Computer Numerical Control. It’s the evolution of the older term “NC”, which stand for simply Numerical Control. CNC refers to the concept of controlling machine tools by computer. You could consider CNC machines as sort of like a robot. With the NC term, a computer wasn’t necessarily involved. The machine might be controlled, for example, by punched tape.

The development of NC – and then later CNC – created an incredible increase in machine tool productivity due to the fact that the machine could be run automatically without requiring the constant attention from an operator. Before the development of this type of automation, there were fewer automation opportunities in the form of hydraulic tracer system. These types of systems used hydraulics to cause the cutting tools of a mill or lathe to follow a template. The taper attachments used for most manual lathes are not dissimilar to the capability of a hydraulic tracer, the tracer just happens to be more capable of creating more elaborate templates.

However, the invention of the first NC and later CNC models dramatically boosted the amount of automation that was possible. CNC machining ranks as the primary method of machining materials today, though the use of manual machining is still fairly common.

For more on detail on CNC, check out our other blog post on the subject.

How Do CNC Machines Make Parts?

The process used to make parts is remarkable straightforward, and involves the following steps:

  1. Part design. Using CAD software to create a 2D or 3D model, CNC machines can then make a part to the exact specifications. CAD stands for “Computer Aided Drafting”, so CAD software is basically just a complex drawing software that lets the user precisely set the dimension of the part they’re designing.
  2. CNC Programming. The second step uses CAM software to cover the CAD model into g-code, a langue used to program CNC machines.
  3. Machine calibration. In this penultimate step, the machine is set using the correct tooling, proper workholding, and the g-code program and tool data are then loaded to the prepare the machine to fabricate the part. The operator will also instruct the machine where to find part zero.
  4. Creating the part. The final step. With everything measured, set up, and ready to go, the part is made.

While this is a simplified description of the process, it should provide a basic understanding of how CNC machines make parts.