Inexpensive PCs as CNC Machine Controllers

Part I, Utilizing an off the shelf PC as a CNC Controller

There are two main groups that can take advantage of today’s low cost PCs as an effective and inexpensive CNC controller.

• Retrofits to existing CNC machines with outdated or proprietary controls in need of service.

• Shop built and home built CNC machines.

Inexpensive PCs can cost as little as $150.00 and yet provide a dependable and effective CNC machine controller. Some sources to consider for obtaining such a system are outpost.com and dell.com. Oupost.com is an outlet for Fry’s electronics. They have one PC on sale ranging from $150.00 to $199.00. Several have successfully used this PC in conjunction with MACH2 CNC controller software.

Tradeoffs: Price vs. Quality. With the lowest cost PCs there a tradeoff in performance, quality, and reliability. The manufacturers of these machines use low cost hardware in their manufacture and they make compromises in the design of the systems to keep their costs down. Inexpensive hardware translates directly to a higher failure rate and more difficult to obtain manufacturer support. This can be a deciding factor by itself if you rely on this machine for production.

Design compromises which are common in low cost PC have an impact on performance. The primary concerns are: insufficient memory, the use of shared memory, and on-board graphics devices. The primary hardware requirements for a PC based CNC controller are sufficient memory, and sufficient processor speed. You can see that the compromises present in these systems are in direct opposition to the requirements for CNC controller.

At the bottom end of the Inexpensive PC market there are off the self solutions that will function well as a PC based CNC controller. As with all things, you tend to get what you pay for, so the buyer is advised to be aware of the requirements and limitations that are in play.

Part II in this series of articles will examine an alternative to buying an off the shelf solution and explore building a PC to meet your specifications.

Dan Staber a Mechanical Engineer offering design, analysis, consultation, and project management services. Dan is also a licensed professional engineer is the states of South Dakota and Washington. For more information please vist - http://www.qacad.com

dcstaber@qacad.com