GRINDSTONE FOR PRECISE MACHINING

• Main Authors: HANDA SADAO, YANO KOZO, KOIWA MASAHIRO
• Format: Patent
• Language: English
• Published: 13.10.1989
• Subjects: GRINDING; PERFORMING OPERATIONS; POLISHING; TOOLS FOR GRINDING, BUFFING, OR SHARPENING; TRANSPORTING

PURPOSE:To improve machining accuracy in precise machining by using abrasive grain and low-carbon low thermal expansion coefficient alloy as a binder. CONSTITUTION:As a low-carbon low thermal coefficient alloy used as a binder, invar and super-inver are cited. The thermal expansion coefficients of these materials change before and after a magnetic transformation point, a low thermal expansion coefficient is shown on low temperature side and a high thermal expansion coefficient is shown on high temperature side. The magnetic transformation point is lower than the sintering temperature of the low-carbon low thermal expansion coefficient alloy. Abrasive grain is mixed using the above low-carbon low thermal expansion alloy powder or mixed powder of the alloy composition as a binder. In case of pressure sintering the abrasive grain, though the abrasive grain can be firmly fixed by pressure sintering itself, the coefficient of contraction due to cooling is large until the magnetic transformation point of the binder so that compressive force is applied to the abrasive grain to further firmly fix and retain the abrasive grain. Furthermore, in case of less than the magnetic tranaformation point, a low thermal expansion coefficient is shown, and as the thermal expansion coefficient can be changed by composition, a grindstone having an arbitrary low thermal expansion coefficient can be obtained.