What is CNC machining and how does it work?

If you’ve ever watched How It’s Made or BBCs rendition with Greg Wallace, Inside The Factory, then you might already have a good idea about CNC machining and how it performs in manufacturing plants. If you’re not familiar with said programmes then stick with us, because Prototype Projects have put together a guide on CNC machining and how it works.

The term CNC stands for computerised numerical control, and these devices were first used in the 1940s and 1950s. CNC machining is just one method of a computer-controlled solution that allows engineers, machinists and makers to create a prototype or part from a computer design file.

Another prototyping process is 3D printing, which is also known as additive manufacturing. The key difference between these two processes is that whilst CNC machining is a subtractive process, 3D printing is an additive process.

Since the invention of CNC machines, the manufacturing sector has been drastically altered and the number of machining steps requiring human intervention has been significantly reduced. CNC automation minimised the number of errors and gave CNC operators more time to do other things, increasing overall productivity.

How does it work?

CNC machines are electro-mechanical devices that can manipulate tools around a varying number of axes with high precision, whilst following instructions from a computer programme.

Machining is a way to transform a stock piece of material such as aluminium, steel or titanium into a finished product, prototype or part.

G-CODE

The first CNC machines were developed in the 1940s & 1950s and relied primarily on a data storage technique known as punched tape. The code to control the machines would be manually punched into a data card and fed into a system which would then interpret the data and produce a prototype. These early machines were rudimentary, and their functionality was somewhat limited.

Nowadays, engineers use computer software to build models using a design-based programme such as Fusion 360° and Solidworks. CAM (computer-aided manufacturing) and CAD (computer-aided design) allow you to build a 3D/digital model, which is then converted into G-CODE and sent to the CNC machine for production.

CADCAM was first introduced in 1976 and by 1989, these CNC machines had become the industry standard.

Types of CNC machines

Milling Machines

Milling machines drill and cut materials to produce components and precision parts for a variety of manufacturing and industrial applications. Since it can perform multiple tasks such as face and shoulder milling, spinning, tapping, and drilling, it is one of the best CNC cutting machine choices.

Plasma Cutters

A CNC plasma cutter is a system that uses plasma torches to easily cut through thick materials. Its precision makes it a favoured option because it only melts the exact areas that need to be cut into, resulting in a cleaner finished product than other CNC machines.

Laser Cutters

Also known as CNC drilling – laser beams are used to cut materials on the CNC laser cutting unit. It works by aiming a powerful laser at the material you want to cut. A laser beam can vaporise, burn, blow away a surface with a jet of gas, or melt it, leaving it with a high-quality finish.

Using CNC machining with Prototype Projects

Prototype Projects stocks numerous types of metal and plastic material that can be machined using CNC machining. These commonly used materials are as followed:

• Aluminium
• Acetal
• Clear Acrylic
• Stainless Steel

Customers can send across part files where our team will review the files for machining suitability. If there are any machining issues or if we need to discuss any concessions that will speed up production or reduce costs we will get in touch. If there are no issues our office team will send our costs to you via email.

Every part file is reviewed by our CNC team, not an algorithm. We offer an Express service for CNC machining, where parts that meet our criteria are dispatched in 3 working days. Read more about CNC machining at Prototype Projects here.