Before computer-integrated manufacturing can reach its full potential for increasing productivity in both design and production, warns a 1984 National Research Council report by the Committee on the CAD/CAM Interface Manufacturing Studies Board, technical advances are needed in several areas. Listed in the increasing order of difficulty, they are:
- data communication in a system in which both hardware and software are heterogeneous
- validation and consistency of data
- representation of integrated textual and geometric data
- expert systems and artificial intelligence
- analytical models of manufacturing processes
Manufacturing Automation Protocol (MAP) is a new way in which industry attempts to tackle problems in data communications.
Data Communication
Three levels of problems in data communications exist for companies attempting to integrate computer-aided design and computer-aided manufacturing. The first level, says the National Research Council's Committee on CAD/CAM Interface, is not a major problem for industry. Companies that use a single computer to run different programs need to have their data in the same format, and to be sure that data remains unchanged when it's transmitted between programs. Many companies are small enough to be able to meet all their design, analysis, machine control, testing, and management needs with one computer, the report says, and so have only a first-level CAD/CAM communication problem.
The second level of communication problem occurs between computers of a single brand. Most large vendors of computers, says the report, offer hardware or software, usually in combination, that lets their different products interface with one another. A company that only uses one brand of computers can choose its communication link to meet its factory requirements, while still providing appropriate times for controls to respond.
The most difficult of communication problems, the report indicates, is providing communication among a variety of systems from many manufacturers. Because different types of computers are better suited to different jobs, most manufacturing companies use many different brands. At one extreme, explains the report, are special purpose microcomputers that control programmable logic-the familiar personal computer. Most of these have real-time on/off control of relays and motors, and their inputs come primarily from switches and other on/off sensors. At the other extreme are large mainframe computers, optimized for processing large files of data, or for tasks that are arithmetically complex.
Until a company has a way of communicating among its computer systems that it may have purchased from many manufacturers, it has a problem when it tries to connect its computer-aided design output with its computer-aided manufacturing activities. It can only interchange data successfully if each pair of communicating systems uses a common protocol-an identical way of doing things-to control communication and to represent data. As a General Motors technical spokesman explains, "In real life, 'protocol' covers a lot of customs. . .the way we say hello, the way we shake hands, and so forth. Different cultures often have different customs. It's the same way with computers. We need to work out an agreed-upon set of rules through which they can [all] talk to each other."
Because there are many different systems, it's not practical for each separate vendor to work out the communication methods. Instead, says the Committee on CAD/CAM Interface, it is important to have a single protocol that each system can use to talk to all others. The International Standards Organization (ISO) is currently working out detailed standards for the required protocols necessary for what it calls Open Systems Interconnection (OSI).
Since 1980, two giant corporations-General Motors and Boeing Computer Services-have been working together to tackle the third level of communications problems. They want to bridge the computer communications gap by setting up data communications standards.
In 1982, General Motors formed a task force that recommended developing and adopting MAP-Manufacturing Automation Protocol-as the sole communications protocol for all its factories. A similar, compatible system, TOP-Technical and Office Protocol-pioneered by Boeing Computer Services in conjunction with the National Bureau of Standards and with MAP, ties engineers and offices together through a common communications protocol.
Here's how Robert L. Dryden, president of Boeing Computer Services, explains the reason behind the joint development effort:
"Our world and our businesses are becoming increasingly more complex. And we require rapid and more detailed access to information," Dryden says. "For example, a modern jetliner like the Boeing 767 contains over V/i million parts. An immense number of design drawings and manufacturing orders are required to assemble just one of these airplanes. When you also consider the intricate processes to make each of those parts, and the data storage that's required, it's easy to understand why the aerospace industry has always tried to use computer-aided technology."
Dryden heads Boeing Computer Services, formed in 1970 to consolidate Boeing's separate computer groups. It currently serves information needs of business, industry, and government through its areas of expertise: artificial intelligence, supercomputing, software engineering, computer-aided design (CAD), computer-aided manufacturing (CAM), systems engineering and integration, and network communications.
Boeing has worked closely with General Motors to tie MAP and TOP together. Both companies believe that having technology that's integrated for office, engineering, and the factory floor is the key to improved quality and productivity.
Vice President of General Motors Corporation Robert J. Eaton, who heads GM's Advanced Engineering Staff as well as the Detroit-based Metropolitan Center for High Technology, has been a MAP supporter and innovator. "MAP is just plain good business sense," he says. "At General Motors, we are preparing ourselves for the future.. .for the day when managers can spend more of their time planning, rather than responding; when supervisors will have up-to-the-minute information to make the best spot decisions to schedule human and machine resources; when production technicians will have the tools and information to do their jobs right the first time."
General Motors has developed a 5-step MAP implementation process of GM facilities, building on systems already found in its manufacturing facilities. "By 1990," Eaton predicts, "the majority of our plants will have implemented major portions of MAP."
