| Popis: |
Some manufacturers, who have invested in sophisticated computer- controlled production equipment, are finding that the technologies do not perform as well as initially expected. While these new automated systems hold the potential for a company to regain a competitive edge by increasing product quality, decreasing production costs, and increasing flexibility, users of such systems are finding that the new production processes are difficult to keep operating. Downtime is a major problem and is expensive in terms of repair costs and lost revenue. The first issue addressed in this study is the extent to which downtime, in general, and maintainability, in particular, is a problem in computer-controlled production systems. We addressed this issue by analyzing failure data in a computer-controlled production process in the automobile industry. This analysis indicates that downtime is a problem and that problems with maintainability are a major contributing factor to the large amounts of downtime. The second issue addressed is the relative contributions of different kinds of failures to downtime and maintainability problems. Addressing this issue can help guide the focus of efforts to reduce downtime. Anecdotal evidence suggests that difficulty in troubleshooting failures via the computerized process controllers is driving the maintainability problems. Analysis of the same failure data mentioned above supports this evidence. The last issue raised is the question of what can be done to design a system of computer-controlled machines so that the system is more maintainable. We propose an experimental design to address this issue. The experiment focuses on two factors which we hypothesize contribute to troubleshooting difficulty and which are also design variables under the control of system designers. These two factors are complexity of the process control logic in the computerized process controllers in the system design and hierarchical arrangement of display pages in the design of the user interfaces. |
