What Is The CNC Machining Process

The CNC machining process to create a PCB board
The CNC machining process to create a PCB board
Resource: https://www.youtube.com/watch?v=xmW3wmmadzI

CNC machining follows a series of steps to create a finished product. The entire CNC machining process, from the design of the part to the actual machining, is explained in detail below. However, to acquaint you with the technology, we will first introduce it before delving into the specifics of the CNC machining steps.

Intro to CNC Machining

CNC machining is used to refer to the process of computerized numerical control in which computers are used to control machine tools. This technology is widely used for a variety of reasons: it can produce parts with very high precision, it is relatively easy to program and set up, and it can be used to create complex shapes.

The first CNC machine appeared in the early 1950s, and since then, the technology has continued to evolve. Today, there are many different types of CNC machining equipment available on the market, each with its own set of capabilities.

Because of its accuracy and versatility, precision CNC machining is used in a wide range of industries, including aerospace, oil and gas, automotive, medical, and consumer goods. In fact, most metal-cutting machinery in the world today is CNC-controlled. The steps for CNC programming and machining are described below.

CNC machining process flow chart
CNC machining process flow chart
Resource: https://www.researchgate.net

The CNC Machining Process

The CNC machining process is the sequence of events that take place in order to manufacture a part using CNC technology. These range from using a computer program to generate the code that will control the machine to setting up the machine and loading the material.

The specific steps involved in CNC machining can vary depending on the type of machine being used and the nature of the part being manufactured. However, four main steps are common. Here, below, is the CNC machine process step by step.

  1. CAD Design

The first step in the CNC machining process is to create a computer-aided design (CAD) model of the part that is to be manufactured. This model will be used to generate the code that will control the machine during the actual machining.

One of the benefits of using CAD to design parts is that it allows for the easy creation of 2 or three-dimensional (3D) models. These models can be rotated and viewed from any angle, which makes it easier to identify potential problems that could arise during the manufacturing process.

2. Converting CAD File to G-Code

Once the CAD model is complete, the next step is to convert it into a computer program known as G-code. The CNC machining code contains a set of instructions that will tell the CNC machine how to move in order to create the desired part. In other words, it’s a universally accepted CNC machining programming language.

CNC machining G-codes can be generated using a variety of software programs. For example, some software programs can generate code for multiple axes, while others are only able to generate code for a single axis.

The type of software used will depend on the complexity of the part being manufactured and the capabilities of the CNC machine being used. Once the G-code is generated, it is typically saved as a text file.

3. CNC Machine Setup

The next step in the process is to set up the CNC machine. The CNC machine setting procedure involves several tasks, such as installing the proper tools, setting up work holding devices, and calibrating the machine.

Installing the proper tools is critical to ensure that the part is machined correctly. The type of tool that is used will depend on the material being machined and the desired finish. For example, a drill bit is typically used to create holes, while an end mill can be used to create both holes and slots.

Workholding devices are used to hold the workpiece in place during the CNC machine process. These can include vices, clamps, and fixtures. The type of device that is used will depend on the size and shape of the stock piece.

Calibrating the machine is also one of the important steps CNC machining process parameters. It ensures that the machine is able to cut the part accurately, according to the G-code instructions. It also ensures tool wear is compensated for and that the machine is able to make any necessary adjustments.

4. Loading Stock Material

The next part of the machining process for CNC equipment is loading the stock material or workpiece. This can be done manually or automatically, depending on the type of machine being used.

With manual loading, the operator will place the material on the machine table and secure it in place. With automatic loading, a robot or other automated device will load the material onto the table.

The method of loading will depend on the size and weight of the material, as well as the type of machine being used, among other factors, such as the required CNC machining procedure. In some cases, multiple pieces of material may need to be loaded onto the machine table in order to machine in a single operation.

5. Machining the Part

After the material is loaded, the actual machining process can begin. During this process, the G-code instructions are fed into the machine, which will then move the cutting tools accordingly.

The specific CNC machining steps involved will depend on the type of part being manufactured. For example, a simple part may only require a few operations, such as drilling and milling. A more complex part may require additional operations, such as grinding or a CNC turning process.

After the machining process is complete, the part can be unloaded from the machine and inspected for quality. The part can be cleaned or coated with a protective finish if necessary.


The CNC machining process can be broken down into several steps, including CAD design, CNC programming, machine setup, and machining. Each step represents an essential stage of manufacturing and must be completed correctly to produce a high-quality part. That means, among other things, ensuring that the right software is being used and the machine is properly calibrated.