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

• Current Assignee: Wayne O. Duescher
• Original Assignee: Wayne O. Duescher
• Inventors: Duescher, Wayne O.
• Primary Examiner(s): Eley; Timothy V
• Application Number:
  US12/217,565
• Publication Number:
  US 20100003904A1
• Time in Patent Office: 1,233 Days
• Field of Search: 279/3, 451/259, 451285-290, 451/342, 451/360, 451/449, 451/494, 451/550
• US Class Current: 451/259
• CPC Class Codes: B24B 37/14 characterised by the composition or properties of the plate materials
• CPC Class Codes: B24B 37/245 Pads with fixed abrasives
• CPC Class Codes: B24B 37/26 characterised by the shape of the lapping pad surface, e.g. grooved
• CPC Class Codes: B24D 18/00 Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for

Abstract

A rotatable abrasive lapper machine platen assembly is attached to a lapper machine frame. The assembly has at least:

• • a) a circular-shaped rotatable horizontal platen having
    • i) a front surface and
    • ii) 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; and
  • 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.

Claims

1. A rotatable abrasive lapper machine platen assembly attached to a lapper machine frame, the assembly comprising:

a) a circular-shaped rotatable horizontal platen having

i) a front surface and

ii) 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.

2. The assembly of claim 1 wherein the composite annular rail support plate middle annular portion is manufactured from a metal, a polymeric or a fiber reinforced polymeric material and has elongated ribs where the ribs have at least two rib ends, a rib thickness, a rib longitudinal length and a rib width, wherein the rib thickness is equal to the full thickness or a partial thickness of the composite annular rail support plate middle portion where the ribs extend equally spaced in a tangential direction around the composite annular rail support plate middle portion whereby the rib ends are attached to both the inner and outer radii of the rail support plate middle annular portion and the rib longitudinal lengths are angled from 20 to 70 degrees from a radial line from the platen center of rotation and the number of ribs contained in a composite annular rail support plate middle annular portion ranges from 4 to 200.

3. The assembly of claim 2 wherein the composite annular rail support plate middle annular portion ribs longitudinal lengths are angled from 35 to 55 degrees from a radial line from the platen center of rotation.

4. The assembly of claim 1 wherein the composite annular rail support plate middle annular portion is constructed from an elastomeric material having low thermal conductivity to provide thermal insulation of the composite annular rail support plate outer annular rail portion from the composite annular rail support plate annular inner rail portion but also wherein the elastomeric annular middle portion provides a radially flexible connection between the composite annular rail support plate outer rail annular portion and the composite annular rail support plate inner rail annular portion.

5. The assembly of claim 1 wherein the platen assembly has fluid passageways that allow fluid coolants to establish and maintain a controlled temperature of the composite annular rail support plate inner rail plate portion of the platen assembly when the air bearing support pads provide cooling to the composite annular rail support plate cantilevered outer annular portion.

6. A process for manufacturing an abrasive lapper machine platen assembly comprising:

a) providing a rotatable abrasive lapper machine platen assembly comprising a circular shaped rotatable horizontal platen having

i) a front surface and

ii) 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) whereby a flexible abrasive disk can be 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 has 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 has 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 is 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 has a composite annular rail support plate that is structurally 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 has 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 structurally 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 structurally 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 having a middle annular portion thickness that is constructed to provide stiff structural 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 also 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 has a lower annular rail air bearing contact surface that faces away from the platen planar front surface whereby this lower rail contact surface is precisely flat and smoothly 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) providing 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) providing a sustained pressurized air film 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) providing 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.

7. The process of claim 6 wherein the composite annular rail support plate middle annular portion is manufactured from a metal, polymeric or a fiber reinforced polymeric material has machined or molded or attached elongated ribs that extend the full thickness or a partial thickness of the composite annular rail support plate middle portion where the ribs extend around the composite annular rail support plate middle portion and the ribs are angled from 20 to 70 degrees from a radial line from the platen center of rotation.

8. The process of claim 7 wherein the composite annular rail support plate middle annular portion ribs are angled from 35 to 55 degrees from a radial line from the platen center of rotation also the ribs provide thermal isolation of the outer rail portion from the inner rail portion.

9. The process of claim 6 wherein the composite annular rail support plate middle annular portion is constructed from an elastomeric material having low thermal conductivity to provide thermal insulation of the composite annular rail support plate outer annular rail portion from the composite annular rail support plate annular inner rail portion but also wherein the elastomeric annular middle portion provides a radially flexible connection between the composite annular rail support plate outer rail annular portion and the composite annular rail support plate inner rail annular portion.

10. The process of claim 6 wherein the platen assembly has fluid passageways that allow fluid coolants to establish and maintain a constant temperature of the composite annular rail support plate inner rail plate portion of the platen assembly when the air bearing support pads provide cooling to the composite annular rail support plate cantilevered outer annular portion.

11. A rotatable abrasive lapper machine platen assembly attached to a lapper machine frame, the lapper machine platen assembly apparatus comprising:

a) a circular shaped rotatable horizontal platen having

i) a front surface and

ii) 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) whereby a flexible abrasive disk can be 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 has 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 has 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 is 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 has a composite annular rail support plate that is structurally 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 has 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 structurally 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 structurally 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 having a middle annular portion thickness that is constructed to provide stiff structural 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 also 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 has a upper annular rail air bearing contact surface that faces toward the platen planar front surface and has a lower annular rail air bearing contact surface that faces away from the platen planar front surface wherein both the upper and the lower rail contact surfaces are precisely flat and smoothly polished and wherein both the upper and lower annular rail air bearing contact surface are co-planar with the platen planar front surface outer annular planar portion surface;

n) wherein multiple sets of opposed upper and lower air bearing pads that are mounted on the lapper machine frame around the periphery of the platen have air bearing pad flat face near-contacts respectively with both the upper and the lower cantilevered annular rail contact surfaces at the same platen circumferential locations 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 moving with a sustained pressurized air film between the opposed air bearing contact surfaces and the polished upper and lower air bearing rail surfaces;

o) wherein the opposed upper and lower air bearing pads each create a pressurized air film between the opposed flat surfaced air bearing contact surfaces and the polished upper and lower air bearing rail surfaces where the air bearing rail outer portion is vertically suspended between the opposed air bearing pads when pressurized air is supplied to the air pads.

12. The apparatus of claim 11 wherein the composite annular rail support plate middle annular portion is manufactured from a metal, a polymeric or a fiber reinforced polymeric material and has elongated ribs where the ribs have two rib ends, a rib thickness, a rib longitudinal length and a rib width where the rib thickness is equal to the full thickness or a partial thickness of the composite annular rail support plate middle portion where the ribs extend equally spaced in a tangential direction around the composite annular rail support plate middle portion whereby the rib ends are attached to both the inner and outer radii of the rail support plate middle annular portion and the rib longitudinal lengths are angled from 20 to 70 degrees from a radial line from the platen center of rotation and the number of ribs contained in a composite annular rail support plate middle annular portion ranges from 4 to 200.

13. The apparatus of claim 12 wherein the composite annular rail support plate middle annular portion ribs longitudinal lengths are angled from 35 to 55 degrees from a radial line from the platen center of rotation.

14. The apparatus of claim 11 wherein the composite annular rail support plate middle annular portion is constructed from an elastomeric material having low thermal conductivity to provide thermal insulation of the composite annular rail support plate outer annular rail portion from the composite annular rail support plate annular inner rail portion but also wherein the elastomeric annular middle portion provides a radially flexible connection between the composite annular rail support plate outer rail annular portion and the composite annular rail support plate inner rail annular portion.

15. The apparatus of claim 11 wherein the platen assembly has fluid passageways that allow fluid coolants to establish and maintain a constant temperature of the inner rail plate portion of the platen assembly when the air bearing support pads provide cooling to the cantilevered outer annular portion.

16. A process for manufacturing an abrasive lapper machine platen assembly comprising:

a) providing a rotatable abrasive lapper machine platen assembly apparatus comprising a circular shaped rotatable horizontal platen having

i) a front surface and

ii) a back surface;

b) wherein the platen has a outer circumference, a periphery and an outer platen annular portion that extends radially to the outer circumference;

c) the platen assembly has a platen center of rotation axis that is perpendicular to the platen planar front surface wherein the rotational axis is concentric with the circular platen;

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

e) the composite rail support plate has 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;

f) wherein the composite rail support plate inner annular portion is structurally 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;

g) wherein the composite rail support plate middle annular portion is structurally 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;

h) wherein the composite rail support plate middle annular portion having a middle annular portion thickness that is constructed to provide stiff structural 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;

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

j) the composite rail support plate cantilevered outer annular portion has a lower annular rail air bearing contact surface that faces away from the platen planar front surface;

k) machining or abrading the lower annular rail outer contact surfaces to produce a precision flat planar lower rail contact surface that is smoothly polished and wherein the lower rail surface is precisely co-planar with the platen planar front surface outer annular planar portion surface;

l) machining or abrading the platen front surface to be precisely co-planar with the lower rail air bearing contact surface.

17. The apparatus of claim 16 wherein the composite annular rail support plate middle annular portion that is manufactured from a metal, a polymeric or a fiber reinforced polymeric material has machined or molded or attached elongated ribs where the ribs have two rib ends, a rib thickness, a rib longitudinal length and a rib width where the rib thickness is equal to the full thickness or a partial thickness of the composite annular rail support plate middle portion where the ribs extend equally spaced in a tangential direction around the composite annular rail support plate middle portion whereby the rib ends are attached to both the inner and outer radii of the rail support plate middle annular portion and the rib longitudinal lengths are angled from 20 to 70 degrees from a radial line from the platen center of rotation and the number of ribs contained in a composite annular rail support plate middle annular portion ranges from 4 to 200.

18. The apparatus of claim 17 wherein the composite annular rail support plate middle annular portion ribs longitudinal lengths are angled from 35 to 55 degrees from a radial line from the platen center of rotation.

19. The apparatus of claim 16 wherein the composite annular rail support plate middle annular portion that is constructed from an elastomeric material having low thermal conductivity to provide thermal insulation of the composite annular rail support plate outer annular rail portion from the composite annular rail support plate annular inner rail portion but also wherein the elastomeric annular middle portion provides a radially flexible connection between the composite annular rail support plate outer rail annular portion and the composite annular rail support plate inner rail annular portion.

20. The apparatus of claim 16 wherein the platen assembly has fluid passageways that allow fluid coolants to establish and maintain a constant temperature of the composite annular rail support plate inner rail plate portion of the platen assembly when the air bearing support pads provide cooling to the composite annular rail support plate cantilevered outer annular portion.

21. A rotatable abrasive lapper machine platen assembly apparatus having a precision flat planar surface whereby a flexible abrasive disk can be secured in conformable flat contact with the platen flat surface;

a) the platen has a platen front surface, a platen outer circumference, a platen periphery and an platen front surface outer platen annular portion that extends radially to the outer circumference wherein the abrasive disk is positioned concentric with the circular platen;

b) the platen has a platen center of rotation axis that is perpendicular to the platen planar front surface wherein the rotational axis is concentric with the circular platen;

c) a vacuum supply passageway located at the platen axis center is connected to one or more radial vacuum passageway slot grooves having slot groove widths and bottom slot groove surfaces that are machined into the platen surface;

d) wherein one or more vacuum annular tangential slot grooves having slot groove widths and bottom slot groove surfaces are machined into the platen outer annular portion surface where the annular tangential slot grooves intersect the radial vacuum passageway slot grooves to provide a vacuum passageway connection between the radial slot grooves and the annular tangential slot grooves;

e) the vacuum annular tangential slot grooves are annular slot groove segments that tangentially span an angular portion of the platen front surface outer platen annular portion or the annular tangential slot grooves extend around the full circumference of the platen thereby intersecting one or more of the radial slot grooves;

h) wherein the radial vacuum passageway slot grooves and the annular tangential slot grooves have slot groove cover plates where the slot groove cover top surfaces are flush with the platen planar front surface outer platen annular portion where open vacuum passageways exist between the slot groove cover plates and the bottom slot groove surfaces of the radial vacuum passageway slot grooves and wherein the slot groove cover plates are attached to the platen surface;

i) wherein the radial vacuum passageway slot grooves and the annular tangential slot grooves cover plates have slot groove cover widths that match the slot groove widths and the machined slot groove annular path configuration of the slot grooves;

j) wherein the annular tangential slot groove covers have vacuum port holes that connect the vacuum passageways to the front surface of the platen to allow the force produced by the vacuum to act on the bottom mounting side of the abrasive disk whereby the flexible abrasive disk acts as a vacuum seal to the vacuum supplied by the grooved vacuum slot passageways with the result that the abrasive disk is bonded to the flat platen surface by the forces provided by the vacuum.

22. The assembly of claim 21 wherein the slot groove cover plates are adhesively bonded to the platen front surface.

23. The assembly of claim 21 where the slot groove cover plates are adhesively bonded to the platen front surface with a bonding adhesive that allows the slot groove cover plates to be removed without damaging the platen front surface whereby a slot groove cover plate can be replaced.