Essay

Energy-Saving Effects ofMicromachine Technology
Tokio Kitahara
Professor,
Mechanical Engineering,
The Faculty of Engineering, Shonan Institute of Technology

create safe and rich lifestyles, but these developments
are also increasing the amount of energy consumption.
Micromachine technology produces machines on theorder of three digits smaller than conventional
machines, resulting in an extremely large energysavings. However, this point has been lessemphasized. Although the power consumed bymechanical systems should be proportional to thesquare or cube of its dimensions, a comparison of apreviously developed microlathe and a working lathe
revealed a proportional power consumption on theorder of 101.5. The amount of energy saved by thisdownsizing was not as large as expected. Apparently
various micromechanical devices developed to datehave exhibited similar results.
The main reason for these results is thought to lie inthe micromachining process. A rough estimation ofpower loss in mechanisms of conventional machines isapproximately 10-30%. This value is reached mainly
by achieving a form accuracy of 10-3-10-4 of the element
dimensions. Applying this to micromachines, accuracyof 1 nm to 1 Å is required for element dimensions of1µm. Currently, however, most micromachine
methods have stalled at a precision of 100 nm, which is10-1-10-2 of the element dimensions. While physicalphenomena, such as adhesion force are prominent in
the microworld, it will be necessary to achieve pinpoint
machining control at the nanometer level to actively
apply or remove the effects of these phenomena. In
other words, nanometer technology is indispensable forfurther advancing micromachine technology. With thistechnology, power loss in micromechanical devices canbe dramatically reduced. I expect the Micromachine
Center to work, from the perspective of energy savings,
on advancing micromachine technology thatincorporates nanotechnology.

Apparently the term "downsizing" originallydenoted the trimming down of a company or otherorganization, although recently it has been used tomean making mechanical systems more compact. The
first portable tape recorder, developed by Tokyo
Tsushin Kogyo (present-day Sony Corporation),weighed eight kilograms and was driven by a spiralspring. The tape recorder was called "Densuke" by an
NHK reporter who carried it on his shoulder while
conducting interviews throughout the country.
Current cassette recorders weigh about 200 grams,
including the power source, or about 1/40 of theDensuke.
Development of the integrated circuit brought
about downsizing of sound and data transmitting
devices and the current trend of portable equipment.
While Densuke required the user to frequently rotate ahandle for recharging, today's cassette recorders canoperate for nearly ten hours on one AA battery. The
difference is primarily due to reducing the size of themechanism's components from centimeters tomillimeters. Accordingly, the energy-saving effects ofdownsizing were realized.
Since micromachines are characterized by being
small and lightweight, technologies for manufacturing
and operating these micromachines (micromachinetechnologies) have emerged to support expectations
that micromachines will be exploited in numerous
industrial fields. R&D on micromachines to date has
yielded a variety of micromachining methods anddiverse microdevices. These devices are already being
used in areas unseen to us. The Micromachine Center
calculated that the production of micromachines has
already reached one trillion yen per year and predicts
that production will expand rapidly in the future.
The objective of technological development is to2