Like the other machines and tools that comprise CNC woodworking as a whole, the CNC router works almost along the same methods as the others. The CNC machine (computer numerical control) uses computer software and CNC controller electronics to drive the mechanical system.
Like the good old traditional router, the new CNC router also moves in 3 directions (usually called X, Y, and Z directions.) The longest is the X axis which runs from front to back.
The Y axis goes from left to right while the Z axis goes up and down. Moving in perfect synch with each other, these routers can carve some very complex shapes with flawless precision and accuracy.
First, a design is inputted into the tandem of the CNC controller and the computer system which acts as the brain for the motors and drive systems. Together, they give the directions where to move, which goes first, how far, etc.
Designs in digital format should be compatible with the CAM software packaged with the CNC controller. This tandem convert a 3D (or 2D) digital image into a tool path code called G-code.
This is then converted into digital signals and relayed to the CNC controller. In turn, the controller converts these into varying voltages and currents that control the movements of the mechanical drive systems.
The spindle is the part that does the actual cutting and is sometimes mistaken to be the actual router itself. It works by rotating a cutting tool (router bits) at different speeds depending on the material to be cut (wood, plastic, metals).
When cutting metals (usually the non-ferrous types like aluminium), there is a coolant system used to cool the materials and the tool itself. There are other tools that may be installed, too – tool sensor, touch probe and automatic tool changer.
Cutting beds come in several designs but have the same functions – to support and secure the materials being cut. The most common are the T-slot and the vacuum tables.
The T-slot blends well with most projects because it has clamps and bolts that secure the material. The T-slot is more versatile because it can hold any piece but lacks efficiency and takes some time to set up.
The vacuum table is best for companies cutting the same design much of the time. However, it goes well only with most wood and sheet materials that have relatively flat surfaces.
Other important components
The CNC linear drive system includes the motor, the linear bearing system, and the lead screw assembly. Every axis uses linear drive system that drives their particular spindles.
The motor links the mechanics and the electronics of the system. There are two types of motors in CNC wood router machines – the stepper and the servo motors.
Stepper motors are cheaper, performs well, and are reliable but they are not a closed loop system. Servo motors use closed loop systems (usually found in high-end models) which send back signals verifying the end of their tasks.
The type of CNC controller is dependent on the motor type used. Controllers for a stepper or a servo motor are different. These are some of the major parts of the CNC routers in current use today. CNC woodworking certainly stepped up with the times.