The Mechanical Engineering Laboratory of the Agency of Industrial Science and Technology, MITI, has been endeavoring to realize the concept of a new production system; a ‘Microfactory’ which would considerably decreases the energy consumption and the space occupied by conventional micro-mechanical fabrication technologies. The world's first prototype of a desktop (50cm x 70cm) machining Microfactory (figure 1) was developed in 1999 and combined miniature machine tools and manipulators. It consisted of a lathe, milling machine, press machine, a transfer arm and a two-fingered hand. The Microfactory was flexible enough to allow reconfiguration of components to meet changes in production specification.

　　As a trial product, the Microfactory was used to fabricate a miniature pivot ball bearing assembly having a 900?m outside diameter. The bearing assembly consisted of ball bearings, a rotary shaft, a housing and a top cover. The lathe was used to manufacture the rotary shaft with a tapered diameter from 100?m to 500?m. The housing, which had a 900?m outer diameter and 700?m inner diameter, was manufactured on the milling machine. The press machine was used to punch out the 120?m thick top cover from a thin metal plate. All parts were transferred from the machining area to the assembly area using the precision positioning transfer arm which was equipped with a negative pressure holding device. In the assembly area, the two-fingered hand located the miniature ball bearings and the rotary shaft into the bearing housing. Attachment of the top cover completed the assembly. Figure 2 shows the individual fabricated parts and the assembled product.

　　The first prototype of the Microfactory proved the concept of space-saving machining and assembly. This year, the second prototype of the Microfactory has been designed to be packaged in a suitcase to demonstrate its portability. This portable Microfactory, shown in Figure 3, has external dimensions 625mm long, 490mm wide and 380mm high and weighs approximately 34kg. It functions entirely stand-alone requiring a single 100V AC power source and, under manual control, is able to demonstrate component machining and transfer operations. We believe this successful realization of the Microfactory concept will be a stimulus to the design of wholly new production systems in the future.

Fig. 3 Newly designed portable microfactory

　

　

---