| 摘要 |
PROBLEM TO BE SOLVED: To make a product whose porosity is a specific volume % or higher and which has a uniform foaming structure without using any foaming agent by forming pores out of vaporized material such as moisture generated at the time of heat-curing reaction of melamine resin. SOLUTION: Abrasive grain is mixed with average 5μm diamond of 25 volume %, melamine resin of 70 volume % as resin and PVA of 5 volume %. The mixture is charged in a temporary forming metallic mold and compressed under pressure of 13.9 MPa at normal temperature. It is then heated at 155 deg.C for 30 minutes in a molding furnace. While heating, the pressure in the molding furnace is increased as much as possible in the range of capable of foaming with vaporized material such as moisture generated at the time of heat-curing reaction of melamine resin, which is indicated in a formula. A wheel is formed, which is like a pellet of 30mm in diameter and 15mm in thickness and has the porosity of 60 to 90 volume %. It is thus possible to distribute pores uniformly in all produced wheels whose porosity of 60, 70, 80 and 90 volume %.
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