US 5,993,298 A · Lapping apparatus and process with controlled liquid flow across the lapping surface

Abstract

Lapping or polishing at high speeds with fine abrasive particles offer significant advantages in the speed of lapping, savings of time in lapping, and smoothness in the finished articles. An improved lapping system comprises a lapper platen system comprising: a) a frame having a total weight of at least 200 kg supporting a work piece holder b) a rotatable platen having an abrasive surface comprising an abrasive sheet secured to said platen; c) a work piece holder which is movable on said frame; d) a means for introducing a first amount of liquid onto said abrasive surface of said platen at a location before contact between a work piece held on said work piece holder and said abrasive surface on said platen; e) a means for introducing a second amount of liquid onto said abrasive surface of said platen after contact between said work piece and said abrasive surface; and f) means for directing air against said abrasive surface after introduction of said second amount of liquid. The process of the present invention may also be described as: 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 directing air against said abrasive surface physically after providing said second amount of liquid to assist in removing said first and second amounts of liquid from said abrasive surface. Rotating said platen at a high rotational velocity generates a surface speed of at least 4,000 surface feet per minute (or even more than 20,000 surface feet per minute). The boundary layer of any liquid (e.g., coolant or lubricant) applied to the working surface of the abrasive sheet is controlled by the apparatus and methods of the invention to improve the uniformity of the lapped surface.

Claims19

Dependent claims

A process for lapping a surface 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 so that said liquid is carried to said area where said 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 second amount of liquid to assist in removing said first and second amounts of liquid from said abrasive surface.

6 more elements

A lapper system comprising:

a) a shaft which is connected to a rotatable platen having vents for air on a front surface of said platen, said platen having a back side to which said shaft is connected and a flat front side on said platen to which can be secured an abrasive sheet by reduced air pressure conveyed through said vents;
b) a frame having a total weight of at least 200 kg supporting a work piece holder and said shaft connected to a rotatable platen;
c) a work piece holder which is movable on said frame;
c) said work piece holder is attached to a movable element on said frame which is capable of moving along said frame in a direction towards and away from said platen to perform lapping of a work piece held on said work piece holder;
d) said work piece holder having control element thereon which allow for independent movement and alignment of said work piece holder along three perpendicular axes so that a work piece on said work piece holder can be adjusted and oriented towards parallelity with said platen so that a work piece can be lapped;
and
e) said control elements having at least 50 settings per rotation, each setting moving said shaft along one of said three axes by a dimension less than 0.05 mm, wherein said lapper system includes a pivoting lapper platen system comprising:
f) a shaft which is connected to a platen, said platen having a back side to which said shaft is connected and a front side on said platen to which can be secured an abrasive sheet, said platen having i) a back surface, ii) a front surface, and iii) a raised edge forming an abrading plateau on said front surface of said rotating platen;
g) a first liquid supply means upstream from said work piece holder with respect to a direction of rotation of said platen;
h) a second liquid supply means downstream from said work piece holder with respect to a direction of rotation of said platen;
and
i) an air blowing means located downstream of said second liquid supply means.

9 more elements

Dependencies are inferred from the claim text.

Lapping apparatus and process with controlled liquid flow across the lapping surface

Life of this patent

Lapping apparatus and process with controlled liquid flow across the lapping surface

Life of this patent

Abstract

Claims19