Machine tool 101: Part 7, Machine tools of the future

Manufacturing Engineering, Jul 1994 by Aronson, Robert B

With CNC controllers, suppliers will retain a certain core technology that will remain proprietary--their competitive edge. But Turner believes there are four areas where open architecture may be practical:

Operator Interface. CNCs will take advantage of the growth in the personal computer market to develop operator interfaces based upon standard PC technology. They will leverage the price and flexibility of both hardware and software from this market to provide interfaces that are user configurable and offer the power of a wide variety of capabilities including on-line documentation and operational instructions, in-process gaging, and quality analysis.

Communications. Controllers will adopt standard communications solutions such as Ethernet, making communications between machine tools, computers, and other process equipment much simpler.

I/O. As the controls industry develops new standards for both field bus and sensor bus, these standards will be integrated into future CNC products to simplify system integration in a multi-vendor environment.

Drives. Although digital drive interfaces remain proprietary, standards may develop. Today, little progress has been made in this area. Initial attempts at developing a drives standard has met with little support from either users or suppliers. To meet demands for high precision and performance, close integration of the servo control function with the CNC is critical. Before a drive standard can be adopted, it must be cost effective and provide all the benefits of performance and reliability of today's proprietary solutions.

SMART LOCATIONS

Computers are getting smarter, smaller, and faster. So the question is no longer "Can we afford them?" but, "Where can they best be utilized?" Mark Adkins, manager, product development for Cincinnati Milacron, agrees with the trend to distribute machine tool control rather than centralize it in the computer. "Because microprocessors are getting smaller, faster, and cheaper, it's practical to make machine tool sensors smarter. Instead of bringing in raw signals from the toolchanger, worktable, and spindle, we get specific performance data that the controller does not have to waste time translating. For example, in a machine we are designing, smart sensors eliminated 314 connections and over a mile of wire. Now a single twisted pair of wires to the toolchanger replaces a 30-wire bundle This has a great secondary benefit in improved reliability."

The user side has a slightly different slant. GM manufacturing engineer Dennis Harvey says, "The debate over distributed versus concentrated intelligence in a machine tool is whether to make the computer or the sensors smarter. I suggest first concentrating on making the entire machine more reliable. There is great leverage in simplification because it leads to improved reliability and maintainability. If reliability is high enough, you may not need all these extra instruments. We would also welcome anything...sensors, software, whatever...that gives us fast error recovery, or better yet, error avoidance.