Say the word “technology,” and most people will think Apple, Microsoft, Uber, Facebook – all the companies and products that seem to have the most direct impact on our day-to-day lives as consumers.
But while social media companies and the makers of hand-held and wireless devices may seem to wield the most influence over our lives, there are a host of other technologies that have a quieter but arguably even more influential role to play in our modern existence. These technologies include the host of manufacturing advances which over the past few decades have made all of those high-tech devices possible.
One of those is our subject today – CNC machining, also known as Computer Numerical Control. We’ll look at what CNC is and how it is used, then take a deeper and more technical dive into how CNC works. We’ll consider some of the major advantages and drawbacks of CNC as well. Finally, we’ll look at similar technologies, and where CNC might go from here.
If you’re looking for more information on CNC training, or just trying to figure out what “CNC” even stands for, this article should help you out. We’ll start with a basic definition of CNC and then move on to flesh out what it is, how it works, and how and where to receive CNC training.
What IS CNC?
CNC: A simple definition
In the simplest terms, Computer Numerical Control allows for the automation of machine tools. Rather than the manual control of a cutting instrument, or even mechanical cutting to a set template, in CNC the computer is fully responsible for moving the cutting heads on a lathe, the wire on an EDM, or the bits on a mill. There may be manual input allowed, but once engaged the computer operates the machine according to a pre-set program.
This program works off a numerical code, known as g-code. G-code is the language of CNC tools; it tells the tool where, when, and what to do. With CNC, a machine operator doesn’t actually tool a part himself, but he or she does tell the machine what to do.
Practical applications of CNC
CNC isn’t a particularly new technology; it’s been around in some form or another since the ‘50s. But the abilities of CNC programming, and the number of machines that are CNC-equipped, has increased dramatically in recent years.
We’ll look at a full list of CNC advantages shortly, but for now, it’s enough to know that CNC-equipped machines allow a single operator to run multiple machines simultaneously,
CNC – Behind the Letters
Advantages of the technology
The most common uses of CNC jobs come in manufacturing and aerospace industries. These companies manufacture highly intricate, complex machines with numerous parts, all requiring precise measurements.
- Greatly expanded design possibilities
When machine equipment operated from input via wheels, gears, and knobs, there were limitations to the complexity of the parts which could be created – or created easily, at least. Modern CNC systems allow machinists to draw up part designs in CAD in 2D or 3D; those designs are then converted into g-code positions by the CNC system.
The limits on what can be done with a given machine now depend far more on the materials involved and the machine itself than the operator. Improved design software further compounds the benefits of CNC; the most advanced design software and the latest CNC machines can together produce parts which simply cannot be manufactured using traditional processes.
The machines themselves gain new abilities with CNC. A single CNC mill or CNC lathe may be able to perform a number of actions in a sequence formerly equivalent to a team of machinists on separate machines. A lathe may be programmed to automatically switch cutting heads mid-operation, saving time in which a normal lathe would need to be turned off, the head switch manually, and then the process resumed.
- Increased efficiency
Calling a CNC system a “computer” isn’t entirely accurate, since it uses a different code; however, the analogy works well enough to see the advantages. An operator for a CNC machine becomes a programmer and troubleshooter rather than someone who must direct every movement of the tool. CNC programs can be saved and repeated; if specific parts are being made, the operator only needs to design a program once, and then make adjustments as needed. Thus, the efficiency of a small shop or machine floor can be greatly increased, since a single operator can be running several machines simultaneously.
In addition, while errors and breakdowns can occur, in theory a CNC machine can operate 24-7, making part after part without human input. Each part can also be made to a high degree of uniformity and accuracy, reducing costly human errors.
Limitations and drawbacks
Are there any limitations to CNC technology? There are a couple. First, like any machine, CNC machines can and do occasionally break down. They also require maintenance – although for tools, this is light and can be performed without seeking expensive professional servicing.
The biggest drawback remains the human element. The programs running CNC machines are still conceived by humans; a poorly-written program will result in a poorly-made part. While most machines can be run by people without extensive experience (an advantage for employers), this can mean that operators lack an in-depth understanding of the process behind machine operations.
Finally, CNC-capable tools frequently cost much more than traditional machine shop tools. While the automation provided by CNC usually creates savings down the road, startup costs may be higher.
What are some of the capabilities most companies require of a CNC-trained candidate? Below are just some of the most common responses:
Next-gen CNC?
Where will CNC technology go next? It’s difficult to tell, but it is possible that the future of CNC is already here. Already, many manufacturers are realising that the natural companion to a CNC tool is a 3D printer. Both work from digital design programs; CNC creates parts through cutting, drilling, and milling process while 3D printers build from the ground up.
The two technologies complement each other well. Currently, 3D printers are limited by the materials they can use, but the technology is improving constantly. Machinists currently have the luxury of deciding which process would work better, given the specifics of each part.