US3579917A

US3579917A - Polishing machine

Info

Publication number: US3579917A
Application number: US776023A
Authority: US
Inventors: Stephen A Boettcher; Louis F Simonetti
Original assignee: Speedfam Corp
Current assignee: Speedfam Corp
Priority date: 1968-11-15
Filing date: 1968-11-15
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25
Also published as: FR2023433A1; DE1957286A1; JPS4814234B1; NL6917238A; GB1236864A

Abstract

A polishing machine load plate unit to which workpieces are affixed for polishing, and through which a liquid is selectively circulated.

Description

United States Patent [72] Inventors Stephen A. Boettcher Deerfield (Riverwoods); Louis F. Simonetti, Morton Grove, Ill. [21 1 Appl. No. 776,023 [22] Filed Nov. 15, 1968 [45] Patented May 25, 1971 [73] Assignee Speedfam Corporation Des Plaines, Ill.

[54] POLISHING MACHINE 7 Claims, 8 Drawing Figs.

52 U.S.Cl 51/131, 51/266 [51] Int.Cl B24b7/04 [50] FieldofSearch 5l/l31, 165.30, 266, 277, 322

[56] References Cited UNITED STATES PATENTS 698,126 4/1902 Miskolczy 51/266 2,998,680 9/1961 Lipkins 51/131 3,110,988 11/1963 Boettcher.... 51/131 Primary Examiner-Lester M. Swingle Attorney-Johnson, Dienner, Emrick, Verbeck & Wagner ABSTRACT: A polishing machine load plate unit to which workpieces are afiixed for polishing, and through which a liquid is selectively circulated.

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Qi aa PATENTEU M25 1971 SHEET 3 OF 3 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a polishing machine comprised of a rotatable polishing wheel assembly, and means for urging workpieces to be polished into engagement with the upper surface of the polishing wheel assembly.

2. Description of the Prior Art One type of polishing machine comprises a horizontal rotatable backing wheel, a polishing cloth extending across the upper surface of the backing wheel, a load plate unit adapted to receive workpieces at the lower surface thereof and to be positioned over the backing wheel with the workpieces engaging the polishing cloth, and means, including a vertical spindle assembly, for centering and applying pressure to the load plate unit. Conventionally, a plurality of workpieces to be polished are affixed, for example by parafiin, to the lower surface of the load plate unit. In this manner, the workpieces are maintained in position relative to the load plate unit, and are movable therewith, during the polishing operation.

With reference to the foregoing arrangement, dissipation of heat generated in the load plate unit during the polishing operation has not been entirely satisfactory in all applications; and mounting of workpieces to, and removal of the same from, the load plate unit occasionally has not been as convenient as might be desired.

SUMMARY OF THE INVENTION In accordance with the present invention, the load plate unit is provided with a central upwardly directed opening, and with passageway means communicating with the opening to accommodate circulation of a fluid coolant interiorly of the unit. Cooperatively, the spindle assembly is provided with fluid transmission means for separately directing to the opening fluid coolant and receiving from the opening coolant which has absorbed heat. In this manner, the load plate unit is cooled to compensate for heat developed therein during the polishing operation.

Additionally, the load plate unit is detachable from the spindle assembly; and, at a location remote from the polishing machine, a fluid of suitable temperature may be circulated through the load plate unit for selectively heating or cooling the same to effect softening or solidification of the mounting medium as may be required while the workpieces are being affixed to or removed from the load plate unit. In this manner, mounting of workpieces to, and removal of the same from, the load plate unit are greatly facilitated.

BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1 is an elevational view, with portions being broken away and shown in section, of a polishing machine incorporating the principles of the present invention;

FIG. 2 is a horizontal view, taken substantially along the line 22 in FIG. 1, looking in the direction indicated by the arrows;

FIG. 3 is a vertical median sectional view, on an enlarged scale, of the load plate unit and spindle assembly of the present invention, and of other machine components associated therewith;

FIG. 4 is a horizontal view, taken substantially along the line 4-4 in FIG. 3, looking in the direction indicated by the arrows;

FIG. 5 is a horizontal view on a reduced scale, taken substantially along the line 5-5 in FIG. 3, looking in the direction indicated by the arrows;

FIG. 6 is a foreshortened front elevational view, with portions being broken away and shown in section, of a workpiecemounting device;

FIG. 7 is a side elevational view, on a reduced scale, of the workpiece-mounting device of FIG. 6; and

FIG. 8 is a horizontal view on a reduced scale, taken substantially along the line 8-8 in FIG. 6, looking in the direction indicated by the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is indicated generally by the reference numeral 10 a polishing machine incorporating the principles of the present invention. The polishing machine 10 comprises a framework including a substantially cylindrical housing 12 supported by a base ring 14. Suitably secured to the opposite sides of the housing 12 are the lower ends of vertical columns 16. Extending between the upper ends of the columns 16 is a horizontal bridge member 18 provided with opposed pairs of lateral arms 20. Mounted at the outer end of each of the four arms 20 is a vertical pneumatic piston and cylinder assembly 22 which includes a cylinder 24, a stabilizer sleeve 26 and a piston rod 28.

A cylindrical collar 30 is mounted at the upper end of the housing 12 by means of an annular inclined wall 32. Also mounted in the housing 12 is a main drive motor 34 operatively connected to a conventional speed reducer unit 36 supported in the collar 30. The output shaft of the speed reducer 36, in a known manner, is connected to, and serves to effect rotation of, a generally horizontal polishing wheel assembly 38 shown in FIGS. 2 and 3.

The polishing wheel assembly 38 is comprised of an annular backing wheel 40 and a polishing cloth 42 extending across the upper face thereof. The backing wheel 40 is preferably formed of a metal, such as brass, having a high heat conductivity. The polishing cloth 42, which may for example be either sail cloth or a synthetic nonwoven cloth, is retained in position by means of a ring or hoop member 44 suitably clamped about the outer periphery of the backing wheel 40. In place of cloth, a felt material may be either clamped to the backing wheel 40 or glued thereon. The polishing wheel assembly 38 is surrounded by an annular thin-walled shroud or shield 46 which is normally maintained in the position shown in FIGS. 1 and 2 to accommodate loading and unloading of the polishing machine, and is adapted to be raised to the position shown in FIG. 3 during polishing operations.

A freely flowing polishing slurry is adapted to be fed to the polishing wheel assembly 38 by tubes or spouts 48 extending downwardly from the bridge member 18 as shown in FIG. I. The slurry is delivered to the spouts 48 through tubing 50 connected to a sump pump unit 52 located in the lower portion of the housing 12. The polishing slurry flowing from the polishing wheel assembly 38 is collected by the inclined wall 32, which serves as a drip pan, and is directed to a drain. The polishing slurry may, by way of example, comprise a polishing compoundsuch as one having an abrasive base of iron oxide, cerium oxide or zirconium oxidesuspended or mixed in water.

Secured in the lower end of each of the piston rods 28 is a vertical spindle assembly 54 comprised of a spindle 56. Each spindle 56 is provided with a first axial passageway 58 and a second axial passageway 60. The first passageway 58 at its lower end is open and at its upper end communicates with a radial inlet 62 which is adapted to be connected to a source of fluid under pressure. The second passageway-60 at its lower end is closed by a plug 64, intermediate of its ends opens outwardly of the spindle 56 through a radial aperture 66, and at its upper end communicates with a radial outlet 68 which is adapted to be connected to a fluid reservoir or drain. The first passageway 58 and inlet 62 define first passageway means, the second passageway 60 and the aperture 66 and the outlet 68 define second passageway means, and the aforesaid first and second passageway means together define fluid transmission means for a purpose to be presently described.

Connected to each of the spindles 56 intermediate 0f the ends thereof is a generally horizontal annular pressure cup 70 having engagement means in the form of an annular ridge 72 at the lower surface thereof. Provided between the spindle 56 and the pressure cup 70 is a floating or swivel connection in the form of a universal ball bearing assembly 74'. The bearing assembly 74 is maintained in assembled position by a snapring 76 engaged in the spindle 56,-and by a snapring 78 engaged in the pressure cup 70. Suitably secured to the spindle 56 immediately above the pressure cup 70 is a collar assembly 80 which serves to shield the bearing assembly 74 from polishing mixture and other foreign material Associated with each pressure cup 70 is a generally horizontal circular load plate unit 82 which, as shown in FIGS. 3, 4 and 5, is comprised of upper and

lower plate sections

84 and 86 secured together by means of a plurality of bolts 88. The upper plate section 84 is formed with a central opening 90, a plurality of radial channels 92 which together with the lower plate section 86 define first radial port means, a plurality of inclined radial ports 94 which define second radial port means, and an annular recess 96 which together with an annular recess 97 formed in the lower plate section 86 defines an annular chamber. The

ports

92 and 94 and the chamber 96 together define passageway means in the load plate unit 82. Mounted within the chamber 96 for dividing the same into upper and lower sections in communication at their outer peripheries is an annular baffle panel 98. A plurality of upwardly and downwardly projecting dimples 100 are formed in the panel 98 and serve to center the panel within the chamber 96.

Mounted within the central opening 90 of the load plate unit 82 are a pair of vertically spaced seal assemblies 102. Each seal assembly 102 comprises an outer body portion 104, and a flexible inner lip portion 106 which is biased radially inwardly by a garter spring 108. The lower end section of the spindle 56 is adapted to be received in the central opening 90 of the load plate unit 82. in this cooperative position, the first passageway 58 in the spindle 56 communicates with the bottom portion of the central opening 90 and the radial ports 92, while the aperture 66 in the spindle 56 communicates with the central opening 90 and the radial ports 94 intermediate of the seal assemblies 102. The garter springs 108 serve to maintain the flexible lip portions 106 of the seal assemblies 102 in engagement with the adjacent periphery of the spindle 56, and the seal assemblies 102 and associated garter springs 108 serve as rotary pressure seal means. The upper surface of the upper plate section 84 is provided with engagement means in the form of an annular recess 110 which is adapted to receive the annular ridge 72 of the pressure cup 70, while the lower surface of the lower plate section 86 is adapted to have affixed thereto work pieces 112.

Referring now to FIGS. 6 and 7, there is indicated generally by the reference numeral 120 a workpiece-mounting device which is adapted to be positioned on a work bench at a location remote from the polishing machine 10. The mounting device 120 includes a generally horizontal housing 122, and an upstanding rectangular frame 124 supported thereon. Secured to the lower leg of the frame 124 is a circular support assembly 126 having a central upstanding nose portion 128. The plate assembly 126 is formed with first passageway means 130 which at one end opens at the upper end of the nose portion 128 and at the other end communicates with an inlet opening 132 adapted to be connected to a source of fluid under pressure. The plate assembly 126 is also provided with second passageway means 134 which at one end opens at the side of the nose portion 128 and at the other end communicates with an outlet opening 136 adapted to be connected to a fluid reservoir or drain. The nose portion 128 is of substantially the same size as the lower end sections of the spindle 56, and is adapted to be received in the central opening 90 of a load plate unit 82. Mounted on the upper leg of the frame 124 is a vertical pneumatic piston and cylinder assembly 138 which includes a cylinder 140 and a piston rod 142 on the lower end of which is mounted a pressure plate 144.

In preparation for polishing, a load plate unit 82 is positioned on the support plate assembly 126 of the workpiecemounting device 120 as shown in FIGS. 6 and 7. A hot fluid medium such as water or steam is then directed through the inlet opening 132, the first passageway means 130, the passageway means of the load plate unit 82, the second passageway means 134, and the outlet opening 136. Next, a thin layer of paraffin, or other suitable mounting substance,

having a melting point lower than the temperature of the fluid being circulated through the load plate unit, is evenly applied to the exposed surface of the load plate unit. workpieces 112 are then positioned in the softened liquified paraffin with the sides of the workpieces to be polished facing upwardly (FIG. 8). To establish an even coating of paraffin between the workpieces 112 and the load plate unit 82, the piston rod 142 may be distended for urging the pressure plate 144 downwardly from the position shown in solid lines in FIGS. 6 and 7 to the position shown in dotted lines in FIG. 6 for applying pressure to the workpieces 112. While pressure is being applied to the workpieces 112, circulation of hot fluid through the support plate assembly 126 and the load plate unit 82 is discontinued, and a fluid coolant such as cold water is circulated through the assembly 126 and unit 82 for solidifying the paraffin and affixing the workpieces 112 to the unit 82. Finally, the pressure plate 144 is retracted upwardly, circulation of coolant is discontinued, and the load plate unit and workpieces afiixed thereto are removed from the mounting device 120 and inverted for transfer to the polishing machine 10.

At the polishing machine 10, load plate units 82 and workpieces 112 affixed thereto are moved onto the polishing wheel assembly 38 and positioned beneath the respective pressure cups 70. The pneumatic assemblies 22 are actuated to distend the piston rods 28 and the spindle assemblies 54 downwardly until the ridges 72 of the pressure cups 70 are engaged under the desired pressure in the recesses 110 of the load plate units 82. At the same time, the lower end sections of the spindles 56 are received in the central openings of the load plate units 82.

Next, the polishing wheel assembly 38 is rotated and polishing material is delivered from the spouts 48 to the surface thereof. Also, a fluid coolant such as cold water is admitted under pressure into the spindle inlet 62, and is transmitted by the first passageway 58 to the bottom portion of the central opening 90 in the load plate unit 82. From the opening 90, the coolant passes through the radial ports 92, around the baffle panel 98 within the chamber 96, through the radial ports 94, and is returned to the central opening 90 intermediate of the seal assemblies 102. From this point, the fluid is transmitted through the spindle aperture 66 and the second passageway 60, and is discharged at the spindle outlet 68. In this manner, the coolant absorbs heat by conduction from the load plate unit 82, and the load plate unit is thereby cooled to offset the heat developed therein during the polishing operation. As workpieces are being polished, the spindles 56 and pressure cups 70 serve to center the load plate units 82, and the bearing assemblies 74 and the seal assemblies 102 accommodate free rotation and floating or swiveling of the load plate units 82.

Upon completion of the polishing operation, drive of the polishing wheel assembly 38, and delivery of polishing material thereto, are interrupted; the introduction of fluid under pressure into the spindle inlet 62 is interrupted; and the spindle assemblies 54 are retracted and the pressure cups 70 withdrawn from engagement with the load plate units 82. Then, the load plate units 82 and workpieces affixed thereto are removed from the polishing wheel assembly 38, inverted, and transferred back to the workpiece-mounting device 120. Hot fluid is circulated through the load plate unit 82 for softening the paraffin whereupon the workpieces are released and become readily removable.

The diameter of each load plate unit 82 may be substantially the same as, less than, or greater than, the radial width of the annular surface of the backing wheel 40. Also, it will be appreciated that in the drawings certain elements-for example, the cloth 42 and workpieces 112-have been exaggerated from the true scale for sake of clarity of illustration.

While there has been shown and described a preferred embodiment of the present invention, it will be understood by those skilled in the art .hat various rearrangements and modifications may be mace therein without departing from the spirit and scope of the invention.

We claim:

1. In a polishing machine having framework, a polishing wheel assembly mounted on the framework on a vertical axis, means for rotating the polishing wheel assembly, at least one vertical spindle assembly supported from the framework above the polishing wheel assembly, a generally horizontal circular load plate unit adapted to have workpieces affixed to the lower surface thereof for engagement with the polishing wheel assembly, and means for selectively establishing interengagement between the spindle assembly and the load plate unit, the improvement which comprises said load plate unit having a central opening, said load plate unit having passageway means communicating with said opening to accommodate circulation of fluid interiorly of said unit for effecting cooling thereof, and said spindle assembly having fluid transmission means for separately directing fluid to and receiving fluid from said opening, said passageway means comprising an annular chamber, first radial port means intermediate said centralopening and said annular chamber for directing fluid to said chamber, and second radial port means intermediate said annular chamber and said central opening for receiving fluid from said chamber.

2. The improvement of claim 1 including means dividing said chamber into upper and lower sections in communication at their outer peripheries; and wherein said first radial port means extends between said central opening and the inner periphery of said lower chamber section, and said second radial port means extends between the inner periphery of said upper chamber section and said central opening.

3. The improvement of claim 1 wherein said spindle assembly has a lower section that projects into said central opening, said fluid transmission means comprises first passageway means in said spindle assembly which is adapted to be connected to a source of fluid under pressure and communicates with said central opening adjacent said first radial port means, and said fluid transmission means further comprises second passageway means in said spindle assembly which communicates with said central opening adjacent said second radial port means and is adapted to be connected to a fluid reservoir.

4. The improvement of claim 3 wherein said interengagement means is comprised of swivel connection means, and including axially apaced seal means in said opening between said lower section of said spindle assembly and said load plate unit on opposite sides of said second radial port means.

5. For use in a polishing machine, a circular load plate unit having a central axial opening at one side of said unit, and having passageway means communicating with said opening to accommodate circulation of fluid interiorly of said unit, said passageway means comprising an annular chamber, first radial port means intermediate said central opening and said annular chamber for directing fluid to said chamber, and second radial port means intermediate said annular chamber and said central opening for receiving fluid from said chamber.

6. The load plate unit of claim 5 including means dividing said chamber into upper and lower sections in communication at their outer peripheries; and wherein said first radial port means extends between said central opening and the inner periphery of said lower chamber section, and said second radial port means extends between the inner periphery of said upper chamber section and said central opening.

7. The load plate unit of claim 6 including axially spaced flexible seal means in said opening on opposite sides of said second radial port means.

Claims

1. In a polishing machine having framework, a polishing wheel assembly mounted on the framework on a vertical axis, means for rotating the polishing wheel assembly, at least one vertical spindle assembly supported from the framework above the polishing wheel assembly, a generally horizontal circular load plate unit adapted to have workpieces affixed to the lower surface thereof for engagement with the polishing wheel assembly, and means for selectively establishing interengagement between the spindle assembly and the load plate unit, the improvement which comprises said load plate unit having a central opening, said load plate unit having passageway means communicating with said opening to accommodate circulation of fluid interiorly of said unit for effecting cooling thereof, and said spindle assembly having fluid transmission means for separately directing fluid to and receiving fluid from said opening, said passageway means comprising an annular chamber, first radial port means intermediate said central opening and said annular chamber for directing fluid to said chamber, and second radial port means intermediate said annular chamber and said central opening for receiving fluid from said chamber.