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High speed flat lapping platen

  • US 8,062,098 B2
  • Filed: 07/07/2008
  • Issued: 11/22/2011
  • Est. Priority Date: 11/17/2000
  • Status: Active Grant
First Claim
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1. A rotatable abrasive lapper machine platen assembly attached to a lapper machine frame, the assembly comprising:

  • a) a circular-shaped rotatable horizontal platen havingi) a front surface andii) a back surface;

    b) the circular platen having a platen radius, a platen outer circumference and a platen outer periphery;

    c) the circular platen front surface having an outer annular planar portion where the platen outer annular planar portion extends radially to the circular platen outer circumference;

    d) a flexible abrasive disk secured in conformable flat contact with the circular platen front surface outer annular planar portion wherein the abrasive disk is positioned concentric with the circular platen;

    e) the platen assembly having a platen center of rotation axis that is perpendicular to the platen front surface outer annular planar portion surface wherein the platen center of rotation axis is concentric with the circular platen;

    f) the platen assembly having a driven platen shaft where one end of the driven platen shaft is attached to the circular platen at the platen center of rotation and the axis of the shaft is concentric with the platen center of rotation axis;

    f) a rotary driven platen shaft bearing attached to the lapper machine frame wherein the platen shaft bearing is mounted concentric with the platen center of rotation axis wherein the shaft bearing restrains the platen assembly in a circular platen radial direction, but allows the platen assembly free motion along the platen center rotational axis;

    g) the platen assembly having a composite annular rail support plate attached to the circular platen back surface where the annular rail support plate is concentric with the circular platen center of rotational axis;

    h) the composite rail support plate having an inner annular portion, a middle annular portion and a cantilevered outer annular portion where the inner, middle and outer portions are all structurally integral portions of the composite annular rail support plate;

    i) wherein the composite rail support plate inner annular portion is attached at the outer diameter of the composite rail support plate inner annular portion to the composite rail support plate middle portion at the inner diameter of the composite rail support plate middle annular portion;

    j) wherein the composite rail support plate middle annular portion is attached at the outer diameter of the composite rail support plate middle annular portion to the composite rail support plate outer portion at the inner diameter of the composite rail support plate outer annular portion whereby the composite rail support plate outer annular portion is cantilevered radially outward from the composite rail support plate middle annular portion;

    k) wherein the composite rail support plate middle annular portion has a middle annular portion thickness that provides interconnection of the attached cantilevered composite rail support plate outer annular rail portion to the composite rail support plate inner annual portion in a platen center of rotation axial direction, but whereby the composite rail support plate middle annular portion provides a platen radially flexible connection between the cantilevered composite rail support plate outer rail annular portion and the composite rail support plate inner rail annular portion;

    l) wherein the composite rail support plate middle annular portion provides thermal insulation of the composite rail support plate cantilevered outer rail plate portion from the composite rail support plate inner rail plate portion;

    m) the composite rail support plate cantilevered outer annular portion having a lower annular rail air bearing contact surface that faces away from the platen planar front surface whereby this lower rail annular contact surface is flat and polished and wherein the lower annular rail air bearing contact surface is co-planar with the platen planar front surface outer annular planar portion surface;

    n) wherein multiple combination-air-bearing pads that are mounted on the lapper machine frame around the periphery of the platen have air bearing pad flat face contact surfaces where the air bearing pad contact surfaces are in near-contact with the composite rail support plate outer annular portion lower cantilevered annular rail contact surface to support and restrain the platen assembly in a vertical direction along the platen center of rotation axis when the platen assembly is stationary or rotationally moving;

    o) wherein a sustained pressurized air film is provided between the air bearing pads contact surfaces and the polished lower air bearing rail surface by pressurized air that is supplied to the air bearing pads;

    p) wherein the flat surfaced combination-air-bearing pads have a pressurized air film air bearing pad portion that provides a positive force against the polished lower air bearing rail surface and an air bearing pad vacuum portion that provides a negative force against the polished lower air bearing rail where the air bearing pressurized air film force opposes the air bearing vacuum portion force.

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