Patent ID: 7393370

Claim:
An apparatus for making molded layers of abrasive compositions for abrasive tools comprising, in combination: (a) an annular rigid outer wall having a radially inwardly facing and a radially outwardly facing wall surface; (b) an annular rigid inner wall disposed in a fixed position within said outer wall and spaced a selected distance from the outer wall, the inner wall having at least a radially outwardly facing surface; (c) a flexible wall having a radially inwardly facing surface and a radially outwardly facing surface and disposed adjacent to the radially an outwardly facing surface of said inner wall, said flexible wall having an upper and lower portion disposed in a fixed position between said inner wall and said outer wall and an intermediate portion flexibly movable to form an expandable, sealed pressure chamber between said inner wall and said flexible wall; (d) a sealed mold space formed between the radially outwardly facing surface of said flexible wall and the radially inwardly facing surface of said outer wall and having a top opening adapted to receive a selected volume of an abrasive molding composition; (e) a source of fluid pressure operatively connected to said pressure chamber to apply a positive pressure to the radially inwardly facing surface of the flexible wall, and thereby selectively cause the intermediate portion of the flexible wall to expand radially outwardly toward said mold space and transfer a radially outwardly pressing force against an abrasive molding composition disposed in the mold space, thereby pressing the abrasive molding composition against the radially inwardly facing surface of said outer wall; (f) a heating component operatively mounted in heat exchanging relationship to said mold space to transfer heat to the abrasive composition disposed in said mold space; and (g) a source of vacuum operatively connected to the mold space to selectively apply a vacuum to the mold space to exhaust gaseous components in the mold space and apply a negative pressure to the radially outwardly facing surface of the flexible wall.