Lapping apparatus and method for high speed lapping with a rotatable abrasive platen

A process for lapping a surface comprising one of the following sequence of steps:

• Sequence of steps A comprising:
• a) providing a work piece to be lapped, having at least one surface to be lapped,
• b) providing a rotating platen having i) a back surface and ii) a flat surface and providing a workpiece which can be adjusted to a position parallel to said platen, said flat surface of said platen having openings therein through which air may flow,
• c) providing a sheet of abrasive material having an abrasive face and a back side, said back side being on said flat surface of said platen with the abrasive face of said sheet facing said at least one surface to be lapped,
• d) reducing gaseous pressure between said back side of said abrasive sheet a-ad said flat surface of said platen to secure said sheet of abrasive material to said flat surface of said platen,
• e) rotating said platen at a rotational speed of at least 500 revolutions per minute and a surface speed at an outermost edge of said platen of at least 1500 surface feet per minute, and
• f) contacting said abrasive face and said at least one surface to be lapped on said work piece;
• Sequence of steps B comprising:
• a) providing a work piece to be lapped, having at least one surface to be lapped, which can be adjusted to a position parallel to said at least one surface of b) where
• b) is a rotating platen having i) a back surface and ii) a flat surface said flat surface of said platen having openings therein through which air may flow,
• c) providing a sheet of abrasive material having an abrasive face and a back side, said back side being on said flat surface of said platen with the abrasive face of said sheet facing said at least one surface to be lapped,
• d) wherein said sheet has an outer edge and an inner edge defining an annular distribution of abrasive, said inner edge having a diameter which is greater than one-third the diameter of said outer edge,
• e) rotating said platen at a rotational speed of at least 500 revolutions per minute, and
• f) contacting said abrasive face and said at least one surface to be lapped on said work piece;
• Sequence of steps C comprising:
• a) providing a work piece to be lapped, having at least one surface to be lapped,
• b) providing a rotating platen having a back side and a front side, said front side facing said work piece and having a flat plateau which is continuous around the perimeter of said front side of said platen and is elevated with respect to a central area on said front side, thereby forming an annular region,
• c) providing a sheet of abrasive material on said flat plateau, said sheet of abrasive material having a front surface with an abrasive face and a back surface, with said abrasive face facing said at least one surface to be lapped,
• d) securing said sheet of abrasive material to said flat surface of said plateau, and
• e) rotating said platen at at least 500 revolutions per minute and contacting said abrasive material and said work piece to remove material from said work piece;
• Sequence of steps D comprising:
• a) providing a workpiece to be lapped, having at least one surface to be lapped,
• b) providing a rotating platen having i) a back surface and ii) a flat surface and providing a workpiece which can be adjusted to a position parallel to said platen by rotation about a pivot joint of a workpiece holder supporting said workpiece, said flat surface of said platen having openings therein through which air may flow, and said back surface having a pivoting joint with a shaft which rotates said platen,
• c) providing a sheet of abrasive material having an abrasive face and a back side, said back side being on said flat surface of said platen with the abrasive face of said sheet facing said at least one surface to be lapped,
• d) reducing gaseous pressure between said back side of said abrasive sheet and said flat surface of said platen to secure said sheet of abrasive material to said flat surface of said platen, and
• e) rotating said platen at a rotational speed of at least 500 revolutions per minute by rotating said shaft, and
• f) contacting said abrasive face and said at least one surface to be lapped on said workpiece, and allowing said workpiece holder to pivot around said pivot joint so that said abrasive sheet and said at least one surface to be lapped become more parallel towards each other;
• Sequence of steps E comprising:
• a) providing a work piece with two surfaces to be lapped,
• b) providing two rotatable platens, each rotatable platen having i) a back surface and ii) a front surface,
• c) providing a sheet of abrasive material having an abrasive face and a back side, said back side being on said front surface of each of said two rotatable platens with the abrasive faces of each said sheet facing the other sheet,
• d) placing said work piece with two surfaces to be lapped between said two rotatable platens, so that each abrasive face faces only one of said two surfaces to be lapped,
• e) rotating said two platens at a rotational speed of at least 500 revolutions per minute,
• f) contacting each of said abrasive faces with said only one of said two surfaces to be lapped, and
• g) lapping said two surfaces of said work piece simultaneously;
• Sequence of steps F comprising:
• a) providing a work piece having two surfaces to be lapped to be lapped, having at least one surface to be lapped,
• b) providing two rotatable platens, each rotatable platen having a back side and a front side, said front side facing a surface to be lapped on said work piece and each of said two platens having a flat plateau which is continuous around the perimeter of said front side of each of said platens and is elevated with respect to a central area on said front side, thereby forming an annular region,
• c) providing a sheet of abrasive material on said flat plateau on each of said two platens, said sheet of abrasive material having a front surface with an abrasive face and a back surface, with each said abrasive face facing only one of said two surfaces on said work piece to be lapped,
• d) securing said sheet of abrasive material to each said flat plateau, and
• e) rotating said platen at at least 500 revolutions per minute and contacting said abrasive material on said two platens and said two surfaces to be lapped on said work piece simultaneously to remove material from said work piece;
• Sequence of steps G comprising:
• a) providing a work piece to be lapped, having at least one surface to be lapped which can be adjusted to a position parallel to said at least one surface of a rotating platen,
• b) providing a rotating platen having i) a back surface and ii) a front surface with a periphery, said front surface of said rotating platen having a raised edge symmetrically disposed about said periphery,
• c) providing a sheet of abrasive material having an abrasive face and a back side onto said raised edge to provide a symmetrical distribution of abrasive material on said rotating platen, said back side being on said front surface of said platen with the abrasive face of said sheet facing said at least one surface to be lapped,
• d) securing said sheet of abrasive material to said front surface of said rotating platen, and
• e) rotating said rotating platen at a rotational speed of at least 500 revolutions per minute, and
• f) contacting said abrasive face and said at least one surface to be lapped on said work piece;
• and
• Sequence of steps H comprising:
• a) providing a work piece to be lapped, having at least one surface to be lapped which can be adjusted to a position parallel to said at least one surface of a rotating platen,
• b) providing a rotating platen having i) a back surface, ii) a front surface, and a periphery,
• c) providing a sheet of abrasive material having an abrasive face and a back side onto said rotating platen, with the abrasive face of said sheet facing said at least one surface to be lapped,
• d) securing said sheet of abrasive material to said front surface of said rotating platen,
• e) rotating said rotating platen at a rotational speed of at least 500 revolutions per minute, and
• f) contacting said abrasive face and said at least one surface to be lapped on said work piece,
• g) providing a first amount of liquid to assist lapping to said abrasive surface physically in front of an area where work piece contacts said abrasive face,
• h) providing a second amount of liquid to assist in washing solid material from said abrasive surface physically after said area, and
• i) directing air against said abrasive surface physically after providing said first amount of liquid to assist in removing said first and second amounts of liquid from said abrasive surface.