Understanding CNC Routers: Function, Uses, and Benefits

When you need to cut a piece of wood or metal, you use a saw. When you need a hole punched through a workpiece, you use a drill. But what if you want to carve or hollow out something? To cut it, without cutting it completely?

That’s when you use a router. From the old word “rout” – to hollow out or carve out – routers are common handheld tools, used to carve or cut out patterns in hard material. Wood, metal, plastics – all of these can be cut and worked with a handheld router.

Like most industrial tools, modern routers have a Computer Numerical Control (CNC) version. These machines integrate CNC technology with traditional tools to allow more precise and more complicated operations.

In this article, we’ll cover the basics of what a CNC router is, how it works, and what it does. 

A quick look at CNC

Computer Numerical Control technology has been around since the 1950s, when mechanical punch cards were used to control a machine’s movements. Today’s CNC machines use computers to map out actions based on a coordinate system. Operators use a computer language known as g-code to program a CNC machine with a set of commands. 

Using X, Y, and Z coordinates – and more, for advanced CNC machines – a g-code program tells the machine where to move; when to turn on the toolhead; how far to cut or drill, and when to stop; a complete set of instructions to create a part or product. 

Benefits of CNC

CNC provides at least two major benefits over manually-operated tools. First there is a great degree of precision. CNC machines, when properly cared for and calibrated, can easily cut to thousands of an inch. Advanced CNC machines might have four or five axes of movement, allowing extremely complicated operations.

And once written, a CNC program to create a certain part is infinitely repeatable. While it may take a long time to write a g-code program for a particular part, that program can be run hundreds or even thousands of times, creating an entire run of parts that are identical and highly precise.

With precision and repeatability comes a third major benefit of CNC machines; automation. With the correct program, CNC machines can run nearly-infinitely without direct human oversight. On modern production lines, you’ll find CNC machines working in conjunction with advanced robotics to supply the material needed for CNC machines to run with very little human intervention.

CNC router uses and application

A CNC router brings all the potential of CNC automation to bear on normal router operations. CNC routers typically consist of a table or bed, on which the workpiece is mounted. Over the bed is an arm or gantry, from which the toolhead is suspended.

When a program is executed, the router can move along the X, Y, and Z axis to carve out a pattern and remove material from the workpiece. A CNC router can create a highly detailed pattern or carving, or it can be used to replace a table saw and section the workpiece.

Routers are similar in many ways to mills, but while routers can be used on harder materials they excel at cutting softer ones, particularly wood. Chip formation and cutting geometry also factor into the equation, making the CNC router the perfect tool for advanced woodworking. 

Making and executing a CNC router program

All CNC machines rely on g-code programs for instruction. Making that program can be done manually, and instructions entered directly into the machine’s control software. This is programming directly in g-code.

But many woodworkers rely on a slightly longer process. First, the design for a new part or pattern will be drawn up in a Computer Assisted Design (CAD) program on a computer. When the design is complete, the file can be exported as a set of vectors.

Those vectors, in turn, are converted into a set of g-code instructions using a Computer Assisted Manufacturing (CAM) program. And finally, the completed program is input and executed in the CNC router.

Concluding Thoughts on CNC Routers

In terms of cutting-edge technology and practical usefulness, there are few tools more appealing to the modern woodworker than a CNC lathe. Skilled CNC operators will be able to take full advantage of a CNC router capabilities, while woodworkers of all levels can use CAD and CAM programs to reduce the need to learn how to program directly in g-code.

And of course, with a CNC router you can produce intricate patterns previously only possible to highly-trained and experienced woodcarvers.