In modern-day manufacturing, technology is forever advancing and it is essential to keep up with the all latest trends. Throughout our history, we have seen a number of methods implemented to manufacture custom parts. Today, CNC machining and 3D printing are seen as two of the most widely used manufacturing processes.

With the rapid growth of 3D printing technology, some believe it has become the first choice for many industries. On the other hand, CNC machining is still considered a reliable standard and there really aren’t many things that don’t involve CNC machined parts somewhere in the process.

Looking at the available technologies and industries utilising CNC machining and 3D printing, how do they work? Which industries prefer one or the other and how do they compare?

What Is CNC Machining?

CNC machining is short for “computer numerical control” and refers to a manufacturing process where pre-programmed computer software dictates the movement of tools and machinery. It essentially supersedes the limitations of manual control and doesn’t require human operators to manually prompt and guide the machining tools.

With CNC machining, punch cards are used to input computer programs using small keyboards. The computer’s memory retains all the required CNC instructions where programmers write and edit the code. As a result, CNC systems offer a much more expansive computational capacity. CNC machining is dynamic in the sense that one can add new instructions to pre-existing programs through changing the code.

The language behind CNC machining is often referred to as the G-code. The code is written to control all the behaviours of a corresponding machine and includes speed, feed rate and coordination. Put simply, CNC machining makes it possible to pre-program the speed and position of machine functions and processes them using specific software. It uses repetitive and predictable cycles with little to no involvement from human operators. These capabilities have resulted in CNC machining being adopted across various manufacturing sectors especially in metal and plastic production.

A typical process starts with a 2D or 3D CAD drawing which is then translated into computer code. This enables the CNC system to effectively and autonomously execute the commands. Once the program is set up, a human operator does a trial run to ensure the code is error-free.

Which Industries Use CNC Machining?

CNC machines are incredibly versatile and they serve a multitude of industries with exceptional results. You will find them in woodworking for various operations such as drilling and routing. The aerospace industry, for example, favours CNC machining because it offers the five-axis option when needed. This functionality means they can manage hard-to-cut materials like Inconel.

In healthcare or the medical industry, CNC machining is essential for micro-machining. This refers to the tiny parts made from all kinds of materials for equipment used in various life-saving applications. Medical applications include parts for pacemakers or titanium joints or bones, not to mention tools and implements for medical professionals.

Another major sector using CNC machines is the automotive industry. Just think of all the shafts, gears, pins and brackets on all vehicle types, from civilian cars, trucks to military vehicles.

There different types of CNC machines and we’ve listed them below:

• CNC Mills
• Lathes
• Plasma Cutters
• Electric Discharge Machines
• Water Jet Cutters

What Is 3D Printing?

Additive manufacturing (3D printing) is the process of making three-dimensional solid objects from a digital file. It involves the process where 3D printers lay down successive layers of material until they complete the object.

3D printing is not too dissimilar from CNC machining in terms of using computer-aided design (CAD) to create an object. Creating an object using 3D printers is an additive process where subtractive manufacturing involves cutting out a piece of metal or plastic using a CNC milling machine for example.

When most people think of 3D printing, they picture a desktop printer but it involves so much more. We can divide 3D printing into metal, fabrics, bio and numerous other industries which is why 3D printing is a combination of diverse industries capable of several different applications.

Some of the major industries using 3D printing in their industrial sectors are as follows:

• Consumer Goods
• Industrial Goods
• High Tech
• Services
• Healthcare sectors

Not all 3D printing systems are the same and some offer different dimensional accuracy. Industrial machines can produce parts with incredible tolerances and if the project requires tight clearances, the manufacturer can oversize 3D print the dimensions and then machined during post-processing. More businesses are becoming involved with 3D printing in their daily operations and many see it as hugely beneficial.

3D Printing Applications

While some materials may overlap, we will only focus on a few of the major ones. CNC mills can work with a large variety of materials like metal alloys, soft and hardwood, thermoplastics, acrylic, foams and machining wax. You may need different cutting tools for the various materials but the interface remains the same and easily interchangeable tools.

For now, 3D printing is a little more limited to the likes of thermoplastics and resins while thermoplastics can be mixed with other materials including wood, metal and ceramics. Industrial or speciality 3D printers are able to print with more exotic materials.

Many manufacturers use 3D printers in their design process for rapid prototyping which as it’s fast and relatively inexpensive. Shoe manufacturers, for example, use 3D printers to create prototypes of their running shoes. In the past, they would spend thousands of pounds and wait weeks for a prototype whereas modern 3D printing has eased the process and only at a fraction of the cost. Additionally, they can instantly make changes to the 3D digital file and reprint the prototype on the same day.

3D printing applications include rapid prototyping, architectural scale models & maquettes, 3D printed prosthesis and movie props. Other interesting uses include reconstructing fossils, replicating ancient artifacts, reconstructing bones and body parts in forensic pathology among others.

Industries that commonly make use of 3D printing technology include:

• Automotive
• Aviation and Aerospace
• Construction
• Architecture
• Consumer Products such as furniture, lights and jewellery to name a few
• Medical and Dental Sector
• Food
• Fashion

Conclusion

When it comes to applications, many see CNC machining as the better option for manufacturing robust, precise and heat-resistant products. In contrast, some sectors prefer 3D printing for rapid prototyping/manufacturing, small batches and exotic applications such as bio-printing, architectural purposes and food printing.

Both technologies have their place in the manufacturing industry. Where one technology may lack, the other excels. Keep in mind when designing your product that using both technologies during production may be the best solution.

Can you name a few more applications or have you created something spectacular using either of the technologies? We’d love to hear from you and see what some of you have created.

For more information on CNC machining or if you need help with your project, get in touch with our team of experts. PRV Engineering manufacture for a wide range of industries including automotive, aerospace, defence and rail among others.