CNC controllers are computer numeric control instruments that operate machinery. Common CNC machines include mills, lathes, grinders, torch tables and welding machines. CNC tasks can be as simple as tracing a linear pattern or as complex as using multiple axes to follow algorithms. Many CNC machines can use up to eight axes of control.

CNC controllers use different forms of computer language, including ladder logic, bitmap, conversational and drawing exchange format. The controller language must be compatible with the CNC machine's application. When purchasing a CNC controller, consider the following:

1. Use a CNC controller retrofit kit to convert a manual machine.

2. Remotely operate a CNC machine with a desktop CNC controller.

3. Save space with a rack-mount CNC controller.

Action Steps
The best contacts and resources to help you get it done

Convert a manual machine into a computer numerical controller machine

CNC controller retrofit kits transform manual machines, usually mills, into CNC machines. These retrofit kits are relatively easy to implement you can typically install them without a CNC technician. Most retrofit kits allow you to operate the machine manually, even after the CNC installation.

I recommend: Order a CNC controller retrofit kit from CNC Masters. The kit contains easy-to-follow instructions and all the components needed to convert a mill to a CNC machine. Southwestern Industries offers custom and standard retrofit kits for converting knee mills. AjaxCNC sells the electronics and software needed to install a CNC control system. The company's retrofit kit can run as a two-, three- or four-axis CNC control and can run in manual mode.

Remotely control your machines with desktop computer numerical controllers

Desktop CNC controllers allow operators to monitor and control the CNC machine from a remote location, typically a nearby office. You install this type of controller on a personal computer. Implementing a desktop CNC controller typically requires installing software on an existing PC and outfitting the machine with compatible CNC hardware.

I recommend: Purchase CNC software and installation hardware from Camsoft. The software allows you to create and customize a computer numerical control controller for any two- to eight-axis CNC machine tool. Super Tech and Associates offers controllers designed to create a complete interface between a CNC machine and a desktop computer. These controllers are ideal for a variety of mills, plasma torches, lasers, flame torches, engraving machines, glue dispensers and water jets.

Purchase rack-mount CNC controllers

Rack-mount CNC controllers are space-saving options for small CNC machines. You can operate rack-mount CNC controllers by either a remote computer or application-mounted interface. These CNC controllers are often for milling, drilling and turning applications.

I recommend: Bosch Rexroth offers compact rack-mount computer numerical control controllers ideal for small CNC machines. The controller can handle up to eight axes. Find CNC controllers with rack-mount front panels at MachineMate. The company's 19-inch rack-mount front panel includes a 12.1-inch color display and adjacent operator keypad.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  CNC controllers are operated by either a servo motor or stepper motor. Servo motors are required when you need precise control. Stepper motors move in incremental steps based on pulses of current.