What Is CNC Machining? An Overview of the CNC Machining Process

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Computer Numerical Control (CNC) machining is a manufacturing process in which pre-programmed computer software dictates the movement of factory tools and machinery. The process can be used to control a range of complex machinery, from grinders and lathes to mills and CNC routers. With CNC machining, three-dimensional cutting tasks can be accomplished in a single set of prompts.




With CNC machining, pre-programmed computer software dictates the movement of factory tools and machinery

The CNC process runs in contrast to — and thereby supersedes — the limitations of manual control, where live operators are needed to prompt and guide the commands of machining tools via levers, buttons and wheels. To the onlooker, a computer numerical control system might resemble a regular set of computer components, but the software programs and consoles employed in CNC machining distinguish it from all other forms of computation.

If you’re interested in utilizing CNC manufacturing to produce various products, find out more about how CNC machining and CNC programming works. You might also want to know about the main types of CNC machinery and the kind of work it can do to see if it can meet your needs.

What is CNC Machining?

When a CNC system is activated, the desired cuts are programmed into the software and dictated to corresponding tools and machinery, which carry out the dimensional tasks as specified, much like a robot.

In CNC programming, the code generator within the numerical system will often assume mechanisms are flawless, despite the possibility of errors, which is greater whenever a CNC machine is directed to cut in more than one direction simultaneously. The placement of a tool in a numerical control system is outlined by a series of inputs known as the part program.

With a numerical control machine, programs are inputted via punch cards. By contrast, the programs for CNC machines are fed to computers through small keyboards. CNC programming is retained in a computer’s memory. The code itself is written and edited by programmers. Therefore, CNC systems offer far more expansive computational capacity. Best of all, CNC systems are by no means static since newer prompts can be added to pre-existing programs through revised code.

CNC Machine Programming

In CNC manufacturing, machines are operated via numerical control, wherein a software program is designated to control an object. The language behind CNC machining is alternately referred to as G-code, and it’s written to control the various behaviors of a corresponding machine, such as the speed, feed rate and coordination.

Basically, CNC machining makes it possible to pre-program the speed and position of machine tool functions and run them via software in repetitive, predictable cycles, all with little involvement from human operators. In the CNC machining process, a 2D or 3D CAD drawing is conceived, which is then translated to computer code for the CNC system to execute. After the program is inputted, the operator gives it a trial run to ensure no mistakes are present in the coding.

Due to these capabilities, the process has been adopted across all corners of the manufacturing sector, and CNC manufacturing is especially vital in the areas of metal and plastic production. Find out more about the types of machining systems used and how CNC machine programming fully automates CNC manufacturing  below:

Open/Closed-Loop Machining Systems

During the CNC manufacturing process, position control is determined through an open-loop or closed-loop system. With the former, the signaling runs in a single direction between the CNC controller and motor. With a closed-loop system, the controller is capable of receiving feedback, which makes error correction possible. Thus, a closed-loop system can rectify irregularities in velocity and position.

In CNC machining, movement is usually directed across X and Y axes. The tool, in turn, is positioned and guided via stepper or servo motors, which replicate exact movements as determined by the G-code. If the force and speed are minimal, the process can be run via open-loop control. For everything else, closed-loop control is necessary to ensure the speed, consistency and accuracy required for industrial applications, such as metalwork.

In CNC machining, movement is usually directed across X and Y axes

CNC Machining Is Fully Automated

In today’s CNC protocols, the production of parts via pre-programmed software is mostly automated. The dimensions for a given part are set into place with computer-aided design (CAD) software and then converted into an actual finished product with computer-aided manufacturing (CAM) software.

Any given workpiece could necessitate a variety of machine tools, such as drills and cutters. In order to accommodate these needs, many of today’s machines combine several different functions into one cell.

Alternately, an installation might consist of several machines and a set of robotic hands that transfer parts from one application to another, but with everything controlled by the same program. Regardless of the setup, the CNC fabrication process allows for consistency in parts production that would be difficult, if not impossible, to replicate manually.

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The Different Types of CNC Machines

The earliest numerical control machines date to the 1940s when motors were first employed to control the movement of pre-existing tools. As technologies advanced, the mechanisms were enhanced with analog computers, and ultimately with digital computers, leading to the rise of CNC machining.

Ultrasonic welding, hole-punching, and laser cutting are the more common CNC-operated processes

The vast majority of today’s CNC arsenals are completely electronic. Some of the more common CNC-operated processes include ultrasonic welding, hole-punching and laser cutting. The most frequently used machines in CNC systems include the following:

CNC Mills

CNC mills are capable of running on programs comprised of number- and letter-based prompts that guide pieces across various distances. The programming employed for a mill machine could be based on either G-code or some unique language developed by a manufacturing team. Basic mills consist of a three-axis system (X, Y and Z), though most newer mills can accommodate three additional axes.


In lathe machines, pieces are cut in a circular direction with indexable tools. With CNC technology, the cuts employed by lathes are carried out with precision and high velocity. CNC lathes are used to produce complex designs that wouldn’t be possible on manually run versions of the machine. Overall, the control functions of CNC-run mills and lathes are similar. As with CNC mills, lathes can be directed by G-code or unique proprietary code. However, most CNC lathes consist of two axes — X and Z.


Plasma Cutters

In a plasma cutter, a plasma torch cuts the material. The process is foremost applied to metal materials but can also be employed on other surfaces. In order to produce the speed and heat necessary to cut metal, plasma is generated through a combination of compressed-air gas and electrical arcs.

Electric Discharge Machines

Electric-discharge machining (EDM) — alternately referred to as die sinking and spark machining — is a process that molds workpieces into particular shapes with electrical sparks. With EDM, current discharges occur between two electrodes, and this removes sections of a given workpiece.

When the space between the electrodes becomes smaller, the electric field becomes more intense and thus stronger than the dielectric. This makes it possible for a current to pass between the two electrodes. Consequently, portions of a workpiece are removed by each electrode. Subtypes of EDM include:

  • Wire EDM: Wire EDM uses spark erosion to remove portions from an electronically conductive material.
  • Sinker EDM: Sinker EDM utilizes an electrode and workpiece soaked in dielectric fluid for the purpose of piece formation.

In a process known as flushing, debris from each finished workpiece is carried away by a liquid dielectric, which appears once the current between the two electrodes has stopped and is meant to eliminate any further electric charges.

Water Jet Cutters

In CNC machining, water jets are tools that cut hard materials, such as granite and metal, with high-pressure applications of water. In some cases, the water is mixed with sand or some other strong abrasive substance. Companies often shape factory machine parts through this process.

Water jets are employed as a cooler alternative for materials that are unable to bear the heat-intensive processes of other CNC equipment. Due to their cooler nature, several sectors like the aerospace and mining industries rely on water jets, where they use them for carving and cutting, among other functions. Companies also use water jet cutters for applications requiring very intricate cuts in material, as the lack of heat prevents any change in the material’s intrinsic properties that may result from metal on metal cutting.

What Else Can CNC Machines Do?

As plenty of CNC machine video demonstrations have shown, companies use CNC equipment to make highly detailed cuts out of metal pieces for industrial hardware products. In addition to the aforementioned machines, you can find several other common pieces of machinery used in CNC manufacturing to produce highly detailed and accurate CNC products. Some of the most common products produced by CNC machines include steel aerospace parts, metal automotive components, wooden decorations and plastic consumer goods pieces.

Since these CNC products have unique requirements, CNC machines regularly utilize other tools and components. Check out some of the primary pieces of machinery used within CNC systems:

  • Embroidery machines
  • Wood routers
  • Turret punchers
  • Wire-bending machines
  • Foam cutters
  • Laser cutters
  • Cylindrical grinders
  • 3D printers
  • Glass cutters

Since CNC machinery can implement so many other tools and components, you can trust it to produce an almost limitless variety of goods quickly and accurately. For example, when complicated cuts need to be made at various levels and angles on a workpiece, it can all happen within minutes on a CNC machine.

As long as the machine is programmed with the right code, the machine functions will carry out the steps as dictated by the software. Providing everything is coded according to design, a product of detail and technological value should emerge once the process has finished.

Choose Astro Machine Works for Your CNC Manufacturing Needs

When you need the best in CNC manufacturing and machinery, turn to Astro Machine Works. We’re backed up by our over 35 years of experience working in the machining industry and staff of expert team members with CNC certification. As a company, we’re dedicated to delivering exceptional value to every client we serve. Due to this commitment, we can produce custom machining parts and components and build custom machinery specifically designed for your company’s needs.

Review our CNC precision machine services today to see what we can do for you. If you have any questions or are ready to partner with us, please contact us.

Categories: CNC Machining