Patent ID: 6869343

Claim:
A machine for grooving a base for a polishing pad, said polishing pad made of a resin material, said machine comprising: a bed; a platen including a hollow shaft member supported by said bed via a bearing so that said hollow shaft member is rotatably about a C-axis which is perpendicular to said bed; a suction plate fixed to one of opposite axial end portions of said hollow shaft member remote from said bed and formed with a plurality of through holes arranged evenly over an entire area thereof for attracting the base for the polishing pad to said suction plate; drive mechanism for rotating said platen about said C-axis and for positioning said platen at a suitable angular position; a gate-shaped column of a shape having two legs which are opposed to each other with a spacing therebetween and a cross rail extending between and being perpendicular to said two legs, said gate-shaped column being movable in a direction of an X-axis with said cross rail extending across said platen; at least one saddle mounted on said cross rail so as to be movable in a direction of a Y-axis extending along said cross rail; a tool rest mounted on said saddle so as to be independently reciprocally movable in a direction of a Z-axis, said tool rest adapted to detachably hold a fixed tool comprising a turning tool comprising a cutting part, said cutting part arranged to have a tooth width within a range of 0.005-1.0 mm, a wedge angle within a range of 15-35 degrees, and a front clearance angle within a range of 65-45 degrees; drive motors for moving and positioning said platen, said column and said saddle and tool rest; and a numerical control apparatus for controlling an operation of said drive motor, wherein said hollow shaft member of said platen is connectable to an air suction device so as to attract said base for said polishing pad on said suction plate by a suction force applied from said air suction device to said base for said polishing pad, and wherein said machine being operable to cut by said turning tool a multiplicity of generally concentric annular grooves into a surface of said base for said polishing pad with said base for said polishing pad being attracted on said suction plate.