What Is CNC Machining, And How Does It Work? Let's Find Out!

Different parts of the CNC machines

Before we go into understanding how the whole CNC machining process works, we need to understand what the different parts of the CNC machine contribute to the machining process. Here is a list of the main parts of a CNC machine –

Machine tool – This is the whole structure of the CNC machine, and it comes in different shapes and sizes. They have different forms like milling machines, lathes, grinders, and routers, and all these machines serve different purposes depending on the industrial needs.

Spindles – Spindles are one of the most important parts of the CNC machines. This is the rotating part of the CNC machine that holds and drives the cutting tool. The speed of the spindles influences the precision and accuracy of the cutting process. So when buying a CNC, one should check the spindle speed, as some industries by default need high-speed spindles for better surface finish.

Cutting tools – Different tools and machining operations need different types of cutting tools. The design of these tools can range from simple drills to complex form tools. The shape of the tool, the material, and the coating of the tool heavily influence the machining of the surface and its surface finishes.

Drive System – Drive system of a CNC machine consists of the ball screws and servo motors. It precisely moves the spindle and the workpiece along multiple axes. The servo motors provide accurate rotational motion, which further gets converted into linear motion with the help of the ball screws.

Control system – The control system is the brain of the CNC machine. The software, computer, and electronic interfaces make a total control system of a CNC machine. It translates the G-Code program into precise movement of the machine tool.

Software – This is another major important part of the CNC machine. They are used to create the 2D/3D models of the parts that are going to be made, then also used to generate the G-Code program based on that same model, also finally, it interprets the G-Code and controls the movement of the machine.

How does the CNC machining process work?

The CNC machining includes several steps that engage all the parts we mentioned and then produce the final product. Here is a step by step explanation of how the whole CNC machining process works –

Designing the CAD model – This step starts with the creation of a Computer Aided Design (CAD) software. Then the engineers use that CAD software to create precise 2D or 3D models of the component, specifying the features, geometries, dimensions, and tolerances of the component. These models serve as the blueprint of the entire machining process.

Convert CAD to CAM – In the next step, the CAD file is imported into the Computer Aided Manufacturing (CAM) software. The CAM software then translates the CAD design into CNC machine-readable G-Code. The G-Code dictates the movement of the CNC machine and its machining work. The CAM software also helps with other things –

Select appropriate cutting tools.
Defining tool paths.
Optimizing cutting speeds and feeds.
Simulating the machining process.

Machine Setup – The next step before the CNC machining process commences is the machine setup part. This step involves securing the workpiece in the machine bed of the CNC machine, selecting the appropriate cutting tools, and then calibrating the machine to ensure a smooth machining operation. Finally, loading the CNC program into the machine’s control unit.

Machining the part – After the whole setup process is done, the CNC starts the machining work. The machine executes the operation as per the programmed commands. The cutting tool starts moving along the designated path, removing materials layer by layer to give the desired shapes. Sometimes it happens with multiple axes for products that need complex engineering. The process continues till the whole product is made as it was intended to.

Post processing – Finally, once the product is made and the machining operation of the CNC is done, you need to take some final post processing steps to ensure good quality of the product manufactured. The finished part is removed from the machine bed, the part should be cleaned to remove any fluid or chips on it. Also, polishing can be required for smoothing the surface, as per the end product’s condition.