CNC

The Process

While the CNC machining process offers various capabilities and operations, the fundamental principles of the process remain largely the same throughout all of them. The basic CNC machining process includes the following stages: Designing the CAD model, converting the CAD file to a CNC program, preparing the CNC machine, and executing the machining operation.

Designing the CAD model is quite a standard procedure, and once an appropriate geometry has been defined, the next step is deciding how much material needs to be removed from each surface. Once the CAD file has been completed, it must be turned into G-code or M-code, which are the languages that order CNC machines what to do. 

The conversion process involves sending the CAD file through a CAM (Computer-Aided Manufacturing) program. These programs are specifically designed for converting CAD files to G-code and M-code and are loaded onto a computer attached to the CNC machine. The geometric code (G-code) controls the movement and speed of cutting heads while the miscellaneous code (M-code) covers any other relevant data that is not directly related to the movement and speed of cutting heads. This might include the use of a coolant or something as basic as when the program starts and ends.

Before the operator runs the CNC program, they must prepare the CNC machine for operation. These preparations include affixing the workpiece directly into the machine, onto machinery spindles, or into machine vises or similar work holding devices, and attaching the required tooling, such as drill bits and end mills, to the proper machine components. Once the machine is fully set up, the operator can run the CNC program. While the CNC machine is running, it will operate in one of the four common CNC machining operations. o remove the right amount of material from the workpiece to the correct dimensions and tolerances, CNC machines use certain basic processes, including Drilling, Milling, Turning, and Routing.

Drilling is the process of creating cylindrical holes in a workpiece by using multi-point drill bits. CNC drilling can produce vertically aligned holes with diameters equal to that of the bit used, but angular drillings are also possible through specialized machine configurations and devices. Milling is a machining technique in which rotating multipoint cutting tools remove material from the workpiece. In CNC milling, there are two ways to feed the machine: either by feeding it in the same direction as that of the tool’s rotation or opposite to its rotational movement. The process can cut shallow, flat surfaces, and flat-bottomed cavities into the workpiece, also known as face milling. It can also perform peripheral milling in which it cuts deep cavities, such as slots or threads in the part.

Turning employs single point cutting tools as part of a machining process that is used to remove material from the rotating workpiece. In CNC turning, the machine—typically a CNC lathe machine—feeds the cutting tool in a linear motion along the surface of rotation on top of it removing any excess until desired dimensions are reached. Operational capabilities of the turning process include boring, facing, grooving, and thread cutting. Lastly, Routing is used for the precision cutting of various materials such as wood, composites, aluminum, steel, and plastics. This process is often used when creating joinery such as mortises or tenons due to its ability to create extremely accurate cut lines time after time.