2001 年 48 巻 5 号 p. 445-450
In-situ measurement of non-uniform sintering shrinkage of guide-type (ring-on-plate) MIM compacts was made by digital image correlation method. The shrinkage distribution and the distortion in the compacts were determined with a dimensional accuracy of 3μm. A periodical shrinkage distribution in the ring portion was observed in the compact during sintering, due to density distribution generated presumably by an uneven injection flow from gates located at the both ends of the base plate. An upward warpage of the base plate and a collapse of the ring portion were also observed. The inhomogeneous radial shrinkage, the base-plate warpage and the ring-collapse were interpreted in terms of the ring-portion density distribution and the effect of gravity. The periodical variation in the radius distribution during sintering was attributed to the green density distribution. A simple geometrical consideration showed that the distortion due to gravity was estimated to be approximately 2% at the most.