Concept proposal of a miniature On-demand factory and its efficiency evaluation

Micro mechanical fabrication is one of practical manufacturing technologies for small and precise products and devices. It mainly covers mesoscopic region between 10 microns and 1 mm. Near the lower limit of the region, it is believed silicon-based technologies are the most efficient processes and mechanical fabrication can be applied only to one-off production. The authors proposed a concept of a miniature factory called ldquoMicrofactoryrdquo and showed that the concept could be rather efficient when the system configuration is designed properly. We insisted the ldquoMicrofactoryrdquo is a hopeful system not only for one-off production, but also for diverse-types-and-small-quantity production. In addition, since manufacturing technologies should be also environmentally conscious, downsizing the manufacturing system can be an option to reduce environmental impact of manufacturing. However, whether the system is really ldquoeco-efficientrdquo has not been examined quantitatively. An appropriate index to evaluate manufacturing systems by considering environmental impacts, costs and system throughput, simultaneously, will help the concept to become more practical. In this report the authors propose an efficiency index named ldquototal performance indicator (TPI).rdquo Using the microfactory as an example, the paper tries to show that the proposed efficiency index is useful in designing configurations of manufacturing systems. Later, the paper also introduces the next generation microfactory which is called ldquoon-demand factoryrdquo to prove that the concept is really practical. Comparison with a conventional system indicates that the on-demand factory is an efficient manufacturing system in environmental and economical aspects.