4 COMPUTERS IN ENGINEERING
Computer Integrated Manufacturing
computer-aided design manufacturing
planning and control
computer-aided manufacture
automated materials handling
processes robotics
computer-aided tests
Figure 1: Islands of computerization in CAM
Microprocessors have been part of the manufacturing process since the 1960s. At first, they were only for certain processes in high-profit companies, because computers were very large and expensive. However, with the advent of the personal computer (PC) in the early 1980s, it became viable to computerize even small processes, taking humans out of tedious operations and unfriendly environments. More and more computers entered manufacturing, but only as aids, not as an integral part of the system. This was sometimes called CAM – computer-assisted manufacturing. The overall process does not change, but certain steps are computerized.
By the end of the 20th century, a totally new and more efficient approach had become possible. CIM, as it is called, interlinks technologies to create the best manufacturing environment, from order to delivery. It spans all facets of business, although engineering plays the central role. However, CIM requires all software and hardware to be compatible, i.e., able to communicate with each other. Unfortunately, many companies have islands of computerization with hardware from different suppliers, and programs written in different languages – BASIC, PASCAL, etc. It is often impossible to pass information from one island to another, so a full CIM system cannot be implemented.
Many companies, therefore, are unable to use CIM. With the alternative, CAM, every step may be computerized, but each is a discrete process. Orders are logged into the computer. The designers then produce detailed drawings, probably using computer-aided design (CAD), with data input from the customer’s specification, as well as current research in product development and manufacturing technologies. The CAD output is then sent to manufacturing engineering, where it is translated into instructions for processes on the shop floor.
computer-aided design
computer-aided tests
database robotics CIM processes
automated materials handling
CIM is very different from CAM. Let us compare CIM and CAM in just one step – the interface between design and engineering. A customer’s specification may require non-standard components or a process that the company does not have. If the designer applies that specification in a CAM environment, the engineering department must order special components and processes to follow the design. With CIM, such problems are avoided. Instead of a linear manufacturing process, as in Figure 1, integrated manufacturing (Figure 2) involves all the enabling technologies revolving around the CIM database, with processes interacting all the time. Designers are automatically reminded of previous similar designs and problems. If a designer asks for a non-standard screw, CIM signals a warning and suggests similar standard screws. If engineering asks for components to be CAMmed in a certain order, CIM prompts that the machine is occupied with another job at that time. If computer-aided testing (CAT) finds a problem in the first batch, this data is immediately fed out to all the enabling technologies so that it can be promptly rectified. Even the salesman can use these technologies when negotiating with customers.
manufacturing planning and control
computer-aided manufacture
Figure 2: The manufacturing process in CIM page xii
CIM is clearly the future. However, companies can only introduce CIM to new factories, and will continue to rely on CAM in existing facilities.
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