| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
The strength of the SiC fiber is higher than hard steels and its rigidity is approximately the same. Therefore, a single SiC fiber is a good candidate for an ultrafine punch. The ultrafine piercing must be conducted without lubricant in continuous processes. Thermal stability of the ceramic fiber is guaranteed, and SiC is stabilized against oxidation by forming an oxygen-impervious silica layer. Besides, ceramics are chemically less reactive to metals. Therefore, a long tool life is expected for ceramics fiber punches. The fiber punch making method employed in our study, by buffing and electrolysis, referred as FPBE process. The ultrafine piercing system is controlled by a personal computer. The computer sends control signals through a D/A converter to (1) a piezoelectric driver, the power source of the piezoelectric actuator, that moves the punch, and (2) the driver unit of the stepping motor that wind the pierced foil while obtaining data through an A/D converter from (3) a load cell
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measuring punch force, and (4) a displacement sensor measuring the punch stroke.
Punch speed is controlled by the change of the piezoelectric driver voltage signal. Metallic foil feed is set by the diameter of the winding drum and the rotation of the stepping motor. The eddy current type displacement sensor for measuring the punch stroke has a maximum measuring length of 1 mm, and does not add up to the punch load measurement because of non-contact type. The load cell for measuring punch loads has the maximum load of 5 N. The forces acting on the load cell vs. punch stroke are measured for both the non-cutting and piercing strokes and the net punch load is obtained from the difference of the two loads. Commercial pure aluminum foil (A1100-H) of 17 thickness, beryllium copper foil (25 alloy-1/4H) of 15 um thickness and stainless steel foil (SUS304-H) of 8 p.m thickness were selected as materials to be pierced. The stainless steel foil is a high strength material and the beryllium copper has a good deformability and can be used as high strength conductive springs. Observation of the pierced hole shows that most of the sheared surface of the aluminum and beryllium copper is a smooth, whereas that of the stainless steel is composed of 66 % smooth and 33 % fractured surface area without burr. After 1000 taps, the punch used for the aluminum foil and beryllium copper foil had no cracks, wear or seizure whereas the stainless steel showed no wear but cracks. Less
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