When Blackstone Valley Regional Vocational Technical High School in Massachusetts was in the market for a lathe to teach its machine shop students the basics of CNC programming, it bypassed traditional dedicated hardware computer numerical controls. The control they selected uses CNC-PC software from Lighthouse Software (Wells, Maine) and runs on any personal computer using Microsoft Windows.

Take a standard off-the-shelf computer, plug in a motion control board, install the CNC-PC software, connect the motors and drives, and you have a CNC control for turning or milling centers. Add a touch screen and enclose it all in a cabinet that will withstand the most hostile machine tool environments and that is Lighthouse Software's alternative to a hardwired CNC. It is about one-third of the cost of a conventional control, and the computer can also be used to run any other programs that will operate under Microsoft Windows. In fact, the computer can be used to create or edit one program while it is running another. CNC-PC software also operates on a network.

This software package takes full advantage of the open architecture of personal computers. This means that additional memory, disk storage capacity, or other upgrades can be purchased from any computer supplier and installed by the user. Adding more processing capability or memory to traditional CNC controls is cost-prohibitive, if not impossible. In many cases, it requires swapping the existing control for a new, more powerful one.

David Lewis, Vocational Team Leader of Blackstone Valley's Industrial Manufacturing and Welding Technology program, heard of CNC-PC through local manufacturers who are on the school's advisory board.

"I thought the PC-based CNC system was an excellent idea," Mr. Lewis says. "A lot of young people today have had exposure to computers, so a PC-based control makes learning CNC programming less intimidating. It takes less time for them to comprehend CNC programming on a PC with the touch screen than it does on our old system with its tape-driven on-board computer. In fact, I'm ahead of schedule in the number of students I have who can run the machine."

The machine shop program at the school was originally designed to give juniors and seniors a CNC background before they entered the labor force. "Now the freshmen and sophomores are learning it," Mr. Lewis notes. "They work twice as hard, and they're able to learn it because they're excellent on computers to begin with. I actually have freshmen staying after school, learning on their own time. I can't say 'no' to a youngster who is willing to work harder to learn. The software comes with an excellent tutorial - a series of lessons that teaches what each window does."

The school's decision to buy the PC-based CNC for its lathe was initially based on its low cost. While conventional controls could cost as much as $15,000, the PC-based control, including CNC-PC software, motion control card, and a PC, costs less than $6,000. Mr. Lewis sees additional advantages to the PC-based system. "The screens used in the CNC-PC are very similar to the screens used in conventional systems. Most controls have similar panels and codes, so what the kids are learning on the PC can be transferred to any system without problems. The software closely emulates most of the controls that are out there." CNC-PC software is fully Fanuc-compatible for milling or turning centers.


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