阅读说明：本技术 一种抛光垫自修整抛光装置及其使用方法 (Polishing pad self-trimming polishing device and using method thereof ) 是由 牛瑞坤 王欢涛 吴钟鸣 于 2021-08-27 设计创作，主要内容包括：本发明属于精密加工技术领域,具体的说是一种抛光垫自修整抛光装置及其使用方法,包括壳体、修整模块、抛光模块、抛光盘、传动轴、驱动模块、抛光垫和控制器,所述壳体水平放置；所述修整模块安装在壳体的上方的右端；所述抛光模块位于壳体上方的左端；所述抛光盘位于壳体内腔上部分,抛光盘用于放置抛光垫；所述抛光垫黏贴在抛光盘上方；所述传动轴的上端与抛光盘相连接,传动轴的下端与驱动模块相连；所述驱动模块用于驱动抛光盘转动；所述控制器用于控制各模块的工作,本本发明通过修整模块、抛光盘、抛光模块和传动轴的相互配合工作能够实现对工件进行高平面度的抛光,并有效的改善抛光后工件的表面质量,进而实现工件的高效精密加工。(The invention belongs to the technical field of precision machining, and particularly relates to a polishing pad self-trimming polishing device and a using method thereof, wherein the polishing pad self-trimming polishing device comprises a shell, a trimming module, a polishing disc, a transmission shaft, a driving module, a polishing pad and a controller, wherein the shell is horizontally arranged; the trimming module is arranged at the right end above the shell; the polishing module is positioned at the left end above the shell; the polishing disc is positioned on the upper part of the inner cavity of the shell and used for placing a polishing pad; the polishing pad is adhered above the polishing disc; the upper end of the transmission shaft is connected with the polishing disc, and the lower end of the transmission shaft is connected with the driving module; the driving module is used for driving the polishing disc to rotate; the controller is used for controlling the work of each module, and the polishing machine can realize the polishing of high flatness of a workpiece through the mutual matching work of the finishing module, the polishing disc, the polishing module and the transmission shaft, effectively improve the surface quality of the polished workpiece and further realize the efficient and precise processing of the workpiece.)

1. A polishing pad self-conditioning polishing apparatus, comprising: the polishing device comprises a shell (1), a finishing module (2), a polishing module (3), a polishing disc (4), a transmission shaft (5), a driving module (6), a polishing pad (7) and a controller, wherein the shell (1) is horizontally placed, and the shell (1) is used for supporting each module; the trimming module (2) is arranged at the right end above the shell (1), and the trimming module (2) is used for trimming a polishing pad (7) on the polishing disc (4); the polishing module (3) is positioned at the left end above the shell (1), and the polishing module (3) is used for polishing a workpiece; the polishing disc (4) is positioned on the upper part of the inner cavity of the shell (1), and the polishing disc (4) is used for placing a polishing pad (7); the polishing pad (7) is adhered above the polishing disc (4), and the polishing pad (7) is used for polishing a workpiece; the upper end of the transmission shaft (5) is connected with the polishing disc (4), the lower end of the transmission shaft (5) is connected with the driving module (6), and the transmission shaft (5) is used for driving the polishing disc (4) to rotate; the driving module (6) is used for driving the polishing disc (4) to rotate; the controller is used for controlling the work of each module; wherein the content of the first and second substances,

the trimming module comprises a motor (21), a connecting seat (22), a lead screw (23), a retainer (24), a fixed seat (25), a hydraulic cylinder (26) and a trimming unit (27), wherein the fixed seat (25) is arranged at the right end above the shell (1), and the upper end of the fixed seat (25) is connected with the lower end of the connecting seat (22); the connecting seat (22) is provided with an inner cavity, the lead screw (23) is positioned in the inner cavity, the upper end of the lead screw (23) is connected with the motor (21), and the lower end of the lead screw (23) is connected with the fixed seat (25); the number of the hydraulic cylinders (26) is 2, the upper ends of the two hydraulic cylinders (26) are connected with the left end of the connecting seat (22), and the lower ends of the hydraulic cylinders (26) are in contact with the trimming module (27); the right end of the retainer (24) is connected with the lead screw (23) through threads, the retainer (24) can move up and down on the connecting seat (22), a circular through hole is formed in the left end of the retainer (24), the trimming unit (27) is placed in the circular through hole, the upper end of the trimming unit (27) is connected with the lower end of the hydraulic cylinder (26), and the lower end of the trimming unit (27) is in close contact with the polishing pad (7).

2. A polishing pad self-conditioning polishing device as recited in claim 1, wherein: the trimming unit comprises a rigid layer (271), a flexible layer (272), an action layer (273) and a trimming layer (274), wherein the rigid layer (271) is positioned at the uppermost end, the upper end of the rigid layer (271) is in contact with the lower end of the hydraulic cylinder (26), and the lower end of the rigid layer (271) is connected with the flexible layer (272); the upper end of the action layer (273) is connected with the left end of the flexible layer (272), the lower end of the action layer (273) is in contact with the polishing pad (7), and the action layer (273) is used for weakening the holding force of abrasive particles in the polishing pad (7); the flexible layer (272) is provided with a rectangular groove; the upper end of the trimming layer (274) is connected with the flexible layer (272), the trimming layer (274) is positioned on the right side of the action layer (273), the left side of the trimming layer (274) is connected with the right side of the action layer (273), and the trimming layer (274) is used for trimming the polishing pad (7).

3. A polishing pad self-conditioning polishing apparatus as recited in claim 2, wherein: the trimming layer (274) comprises a base body (276), soluble substances (275) and v-shaped through holes (277), the base body (276) and the soluble substances (275) are mixed and solidified into a semicircular solid, the v-shaped through holes (277) are uniformly and outwards distributed along the circumference with the circle center of the semicircular solid as a base point, and the upper ends of the v-shaped through holes (277) are communicated with the rectangular groove of the flexible layer (272).

4. A polishing pad self-conditioning polishing device as recited in claim 1, wherein: the two hydraulic cylinders (26) are connected in series through a first hydraulic valve (261), and each hydraulic cylinder (26) is connected with an oil tank (263) through a second hydraulic valve (262).

5. A polishing pad self-conditioning polishing device as recited in claim 1, wherein: the left front end of the connecting seat (22) is provided with an ultrasonic sensor, and the ultrasonic sensor is used for detecting the flatness of the surface of the polishing pad (7).

6. The use method of the polishing device for self-dressing of the polishing pad is characterized by comprising the following steps:

s1, adhering the polishing pad (7) to the polishing disc (4), driving the lead screw (23) to rotate through the motor (21), driving the retainer (24) to move downwards through the rotating lead screw (23) as the right end of the retainer (24) is in threaded connection with the lead screw (23), and powering off the motor (21) after the lower end of the retainer (24) reaches a certain distance from the polishing pad (7);

s2, placing the trimming unit (27) into the circular through hole of the holder (24), and directly contacting the trimming layer (274) and the action layer (273) with the surface of the polishing pad (7);

s3, opening a first hydraulic valve (261) to enable two hydraulic cylinders (26) to be connected in series, opening a second hydraulic valve (262) to enable hydraulic oil in an oil tank (263) to flow into the hydraulic cylinders (26), extending telescopic rods of the hydraulic cylinders (26), enabling the rigid layer (271) to be subjected to stable pressure due to the fact that the lower ends of the telescopic rods of the hydraulic cylinders (26) are connected with the rigid layer (271), enabling stable extrusion effects to exist between the action layer (273) and the finishing layer (274) and the polishing pad (7), and closing the second hydraulic valve (262) after certain pressure is achieved;

s4, the driving module (6) drives the polishing disk (4) to rotate through the transmission shaft (5), and the polishing pad (7) adhered on the polishing disk (4) also rotates along with the rotation, so that the polishing pad (7) generates friction with the action layer (273) and the trimming layer (274);

and S5, detecting the flatness of the polishing pad (7) in the trimming area by the ultrasonic sensor positioned at the left end of the holding frame (24), transmitting a detected signal to the controller, and stopping trimming the polishing pad (7) after the flatness of the trimmed polishing pad (7) meets the requirement.

7. The method for using a polishing pad self-dressing polishing device according to claim 6, wherein the step S4 is embodied as follows:

the method comprises the following steps of (1) guiding finishing liquid containing tiny particles outside to a position between a polishing pad (7) and a contact part of an action layer (273) and a finishing layer (274), wherein the action layer (273) is higher in hardness and is positioned in front of the finishing layer (274), so that a stronger friction effect is generated between the action layer (273) and the polishing pad (7) firstly, the tiny particles generate a scratching effect on the polishing pad (7), the holding force of abrasive particles in the polishing pad (7) is reduced, and even invalid abrasive particles with smaller holding force can fall off; because the soluble substance (275) in the finishing layer (274) is dissolved in water and the dissolution speed is increased along with the increase of the temperature, pits with different sizes are formed on the surface of the finishing layer (274), and the tiny particles can wipe the pits to promote the dissolution of the soluble substance (275) and increase the sizes of the pits; the abrasive particles with weakened holding force are embedded into the concave pits under the action of extrusion, so that the abrasive particles are effectively separated under the action of rotation of the polishing pad (7), and the separated abrasive particles flow out of the range of the polishing pad (7) along with the flow of the dressing liquid;

because the flatness of the failed polishing pad (7) is relatively good, the effective protrusion heights of the abrasive particles in the polishing pad (7) are not different greatly, the width of the effective protrusion embedded in the pit is larger, but the protrusion heights of the effective abrasive particles re-exposed from the polishing pad (7) are larger along with the continuous falling of the failed abrasive particles, the width of the effective protrusion capable of cutting into the pit is reduced, the holding force of the pit on the abrasive particles is reduced, and the effective abrasive particles re-exposed from the polishing pad (7) are prevented from falling again; however, the height of the projections of the effective abrasive grains newly exposed from the polishing pad (7) is different, so that the flatness value of the polishing pad (7) is increased, the abrasive grains with larger height of the projections can be embedded into the v-shaped through holes (277) in the trimming layer (274), under the holding action of the rotating polishing pad (7) and the v-shaped through holes (277), the abrasive grains can fall off, a part of the fallen abrasive grains can enter the rectangular grooves of the flexible layer (272) through the v-shaped through holes (277), the difference between the effective projections among the effective abrasive grains is reduced, and the flatness of the polishing pad (7) is improved.

8. The method of using a self-conditioning polishing apparatus for polishing pads as recited in claim 6, further comprising the following steps after step S5:

s6, placing the workpiece on a polishing pad (7), and polishing the workpiece under the action of a polishing module (3) and a rotating polishing disc (4), so that the phenomena of more scratches and larger surface roughness after polishing caused by insufficient polishing of the workpiece due to uneven height distribution of abrasive particles after the polishing pad (7) is trimmed are avoided, and the polishing pad (7) is effectively trimmed, thereby improving the surface quality of the workpiece.

Technical Field

The invention belongs to the technical field of precision machining, and particularly relates to a polishing pad self-trimming polishing device and a using method thereof.

Background

The polishing pad self-dressing is mainly applied to dressing the polishing pad in the polishing process, so that polishing impurities generated in the polishing process can be removed, and the phenomenon that the polishing impurities block grooves of the polishing pad to influence the using effect of the whole polishing pad is avoided. Therefore, if the polishing pad self-trimming polishing device can timely and effectively remove impurities generated in the polishing process, the polishing effect of the polishing pad can be effectively maintained, and the service life of the polishing pad is prolonged.

From the above, it can be seen that the quality of the polishing pad directly affects the surface quality of the polished workpiece at a certain level, and therefore, it is important to effectively condition the polishing pad before polishing.

In the prior art, manual dressing is mostly adopted for dressing hydrophilic polishing pads, so that incomplete dressing of the polishing pads exists, namely invalid abrasive particles in the polishing pads cannot be effectively fallen off; after the manual trimming, the flatness of the polishing pad is increased, so that the difference of the height of the protrusions of the effective abrasive particles in the polishing pad just trimmed is large, namely, the stability of the polishing quality of the polishing pad is reduced, further, the polishing process is insufficient for the surface of a workpiece, more scratches are generated, and the surface quality of the polished workpiece is reduced.

In view of the above, the polishing pad self-trimming polishing device provided by the invention can efficiently and stably trim the polishing pad through the mutual cooperation of the trimming module, the polishing disc, the polishing module and the transmission shaft, improve the flatness and surface quality of a polished workpiece, and further realize efficient precision machining of the workpiece.

Disclosure of Invention

In order to make up for the defects of the prior art, the invention provides a polishing pad self-trimming polishing device which is mainly used for efficiently and stably trimming a polishing pad so as to realize high-precision and high-flatness polishing of a workpiece. According to the invention, the workpiece can be polished with high flatness through the mutual matching work of the trimming module, the polishing disc, the polishing module and the transmission shaft, the surface quality of the polished workpiece is effectively improved, and further the efficient precision machining of the workpiece is realized. Meanwhile, the invention has simple structure, convenient operation and convenient use.

The technical scheme adopted by the invention for solving the technical problems is as follows: the invention discloses a polishing pad self-trimming polishing device which comprises a shell, a trimming module, a polishing disc, a transmission shaft, a driving module, a polishing pad and a controller, wherein the shell is horizontally placed and used for supporting each module; the dressing module is arranged at the right end above the shell and is used for dressing a polishing pad on the polishing disk; the polishing module is positioned at the left end above the shell and is used for polishing a workpiece; the polishing disc is positioned on the upper part of the inner cavity of the shell and used for placing a polishing pad; the polishing pad is adhered above the polishing disc and used for polishing the workpiece; the upper end of the transmission shaft is connected with the polishing disc, the lower end of the transmission shaft is connected with the driving module, and the transmission shaft is used for driving the polishing disc to rotate; the driving module is used for driving the polishing disc to rotate; the controller is used for controlling the work of each module.

The trimming module comprises a motor, a connecting seat, a lead screw, a retainer, a fixed seat, a hydraulic cylinder and a trimming unit, wherein the fixed seat is arranged at the right end above the shell, and the upper end of the fixed seat is connected with the lower end of the connecting seat; the connecting seat is provided with an inner cavity, the lead screw is positioned in the inner cavity, the upper end of the lead screw is connected with the motor, and the lower end of the lead screw is connected with the fixed seat; the number of the hydraulic cylinders is 2, the upper ends of the two hydraulic cylinders are connected with the left end of the connecting seat, and the lower ends of the hydraulic cylinders are in contact with the trimming module; the left end of the retainer is connected with the lead screw through threads, the retainer can move up and down on the connecting seat, a circular through hole is formed in the left end of the retainer, the trimming unit is placed in the circular through hole, the upper end of the trimming unit is connected with the lower end of the hydraulic cylinder, and the lower end of the trimming unit is in close contact with the polishing pad; the trimming unit comprises a rigid layer, a flexible layer, an action layer and a trimming layer, wherein the rigid layer is positioned at the uppermost end, the upper end of the rigid layer is contacted with the lower end of the hydraulic cylinder, the lower end of the rigid layer is connected with the flexible layer, and the rigid layer is used for connecting other modules and the flexible layer; the upper end of the action layer is connected with the left end of the flexible layer, the lower end of the action layer is in contact with the polishing pad, and the action layer is used for weakening the holding force of abrasive particles in the polishing pad; the flexible layer is provided with a rectangular groove; the upper end of the trimming layer is connected with the flexible layer, the trimming layer is positioned on the left side of the action layer, the left side of the trimming layer is connected with the right side of the action layer, and the trimming layer is used for trimming the polishing pad; the trimming layer comprises a base body, soluble substances and v-shaped through holes, the base body and the soluble substances are mixed and solidified into a semicircular solid, a plurality of v-shaped through holes are uniformly and outwardly distributed along the circumference by taking the circle center of the semicircular solid as a base point, and the upper ends of the v-shaped through holes are communicated with the rectangular groove of the flexible layer; the two hydraulic cylinders are connected in series through a first hydraulic valve, and the hydraulic cylinders are connected with an oil tank through a second hydraulic valve; the left front end of connecting seat is equipped with ultrasonic sensor, and ultrasonic sensor is used for detecting the plane degree on polishing pad surface.

The invention has the beneficial effects that:

1. according to the polishing pad self-trimming polishing device, the trimming module, the polishing disc and the transmission shaft are matched with each other, so that high-flatness polishing of a workpiece can be realized, the surface quality of the polished workpiece is effectively improved, and efficient and precise machining of the workpiece is further realized.

2. According to the polishing pad self-trimming polishing device, the trimming module comprises the motor, the connecting seat, the lead screw, the retainer, the fixing seat, the hydraulic cylinder and the trimming unit, the polishing pad is effectively and stably trimmed by the stable extrusion action between the trimming unit and the polishing pad and the limiting action of the retainer on the trimming unit through the hydraulic cylinder connected in series, and therefore the stability and the efficiency of trimming the polishing pad are improved.

3. The invention discloses a polishing pad self-trimming polishing device, wherein a trimming unit comprises a rigid layer, a flexible layer, an action layer and a trimming layer; the dressing layer, the action layer and the flexible layer are connected, so that the phenomenon that abrasive particles are crushed due to overlarge pressure among the dressing layer, the action layer and the polishing pad in the dressing process is avoided, and the dressing stability is improved; meanwhile, in the process of trimming the polishing pad, the acting layer firstly weakens the held force of abrasive particles in the polishing pad, pits left in the trimming layer by the dissolubility of soluble substances are used for carrying out falling treatment on ineffective abrasive particles, and then the V-shaped through holes in the trimming layer are used for further falling action on the abrasive particles with larger protruding height, so that the phenomenon that the workpiece is insufficiently polished due to the uneven height distribution of the abrasive particles after the polishing pad is just trimmed is avoided, more scratches and the phenomenon that the surface roughness is larger after polishing are generated, meanwhile, the polishing pad is effectively trimmed, the flatness of the trimmed polishing pad is also improved, and the surface roughness and the flatness of the polished workpiece are improved.

Drawings

The invention will be further explained with reference to the drawings.

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of a trimming module;

FIG. 3 is a schematic structural view of a dressing unit;

FIG. 4 is a schematic view of the attachment of the flexible layer to the finishing layer;

FIG. 5 is a schematic view of the distribution of v-shaped vias over the trim layer;

fig. 6 is a schematic view of the working principle of the hydraulic cylinder.

In the figure: the polishing machine comprises a shell-1, a finishing module-2, a polishing module-3, a polishing disk-4, a transmission shaft-5, a driving module-6, a polishing pad-7, a motor-21, a connecting seat-22, a lead screw-23, a retainer-24, a fixed seat-25, a hydraulic cylinder-26, a finishing unit-27, a rigid layer-271, a flexible layer-272, an action layer-273, a finishing layer-274, a base body-276, a soluble substance-275, a v-shaped through hole-277, a first hydraulic valve-261, a second hydraulic valve-262 and an oil tank-263.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

As shown in fig. 1 to 6, the polishing apparatus for self-dressing polishing of a polishing pad according to the present invention includes a housing 1, a dressing module 2, a polishing module 3, a polishing disk 4, a transmission shaft 5, a driving module 6, a polishing pad 7, and a controller, wherein the housing 1 is horizontally disposed, and the housing 1 is used for supporting the modules.

The dressing module 2 is installed at the right end above the housing 1, and the dressing module 2 is used for dressing the polishing pad 7 on the polishing disk 4. The polishing module 3 is located at the left end above the shell 1, and the polishing module 3 is used for polishing a workpiece. The polishing disk 4 is positioned at the upper part of the inner cavity of the shell 1, and the polishing disk 4 is used for placing a polishing pad 7. The polishing pad 7 is adhered above the polishing disk 4, and the polishing pad 7 is used for polishing a workpiece. The upper end of transmission shaft 5 is connected with polishing dish 4, and the lower extreme of transmission shaft 5 links to each other with drive module 6, and transmission shaft 5 is used for driving polishing dish 4 and rotates. The driving module 6 is used for driving the polishing disk 4 to rotate. The controller is used for controlling the work of each module. When the polishing device works, firstly, the polishing pad 7 is adhered to the polishing disk 4, the driving module 6 drives the polishing disk 4 to rotate through the rotating shaft 5, the polishing pad 7 on the polishing disk 4 rotates along with the polishing pad 7, the polishing pad 7 is trimmed under the action of the trimming module 2 because the polishing pad 7 is directly contacted with the lower end of the trimming module 2, and the polishing disk 4 stops rotating after the polishing pad 7 is trimmed; the workpiece is then placed on the polishing pad 7 and polished by the polishing module 3 and the rotating polishing disk 4.

The trimming module comprises a motor 21, a connecting seat 22, a lead screw 23, a retainer 24, a fixed seat 25, a hydraulic cylinder 26 and a trimming unit 27, wherein the fixed seat 25 is arranged at the right end above the shell 1, and the upper end of the fixed seat 25 is connected with the lower end of the connecting seat 22. The connecting seat 22 is provided with an inner cavity, the lead screw 23 is positioned in the inner cavity, the upper end of the lead screw 23 is connected with the motor 21, and the lower end of the lead screw 23 is connected with the fixed seat 25. The number of hydraulic cylinders 26 is 2, the upper ends of two hydraulic cylinders 26 are connected with the left end of connecting base 22, and the lower ends of hydraulic cylinders 26 are in contact with trimming module 27. The right end of the retainer 24 is connected with the lead screw 23 through threads, the retainer 24 can move up and down on the connecting seat 22, a circular through hole is formed in the left end of the retainer 24, the trimming unit 27 is placed in the circular through hole, the upper end of the trimming unit 27 is connected with the lower end of the hydraulic cylinder 26, and the lower end of the trimming unit 27 is in close contact with the polishing pad 7.

The trimming unit comprises a rigid layer 271, a flexible layer 272, an action layer 273 and a trimming layer 274, wherein the rigid layer 271 is positioned at the uppermost end, the upper end of the rigid layer 271 is in contact with the lower end of the hydraulic cylinder 26, the lower end of the rigid layer 271 is connected with the flexible layer 272, and the rigid layer 271 is used for connecting other modules and the flexible layer 272; the upper end of the active layer 273 is connected to the left end of the flexible layer 272, the lower end of the active layer 273 is in contact with the polishing pad 7, and the active layer 273 serves to reduce the holding force of abrasive grains in the polishing pad 7.

The flexible layer is provided with a rectangular groove; the upper end of the trimming layer 274 is connected to the flexible layer 272, the trimming layer 274 is located on the right side of the active layer 273, the left side of the trimming layer 274 is connected to the right side of the active layer 273, and the trimming layer 274 is used for trimming the polishing pad 7; the trimming layer 274 comprises a base 276, a soluble substance 275 and v-shaped through holes 277, the base 276 and the soluble substance 275 are mixed and solidified into a semicircular solid, a plurality of v-shaped through holes 277 are uniformly distributed outwards along the circumference by taking the center of the semicircular solid as a base point, and the upper ends of the v-shaped through holes 277 are communicated with the rectangular groove of the flexible layer 272.

The two hydraulic cylinders 26 are connected in series through a first hydraulic valve 261, and the hydraulic cylinders 26 are connected with an oil tank 263 through a second hydraulic valve 262; the left front end of the connecting seat 22 is provided with an ultrasonic sensor, and the ultrasonic sensor is used for detecting the flatness of the surface of the polishing pad 7. When the polishing machine works, the polishing pad 7 is firstly adhered to the polishing disk 4, then the motor 21 drives the lead screw 23 to rotate, the rotating lead screw 23 drives the retainer 24 to move downwards due to the fact that the right end of the retainer 24 is in threaded connection with the lead screw 23, and the motor 21 is powered off after the lower end of the retainer 24 is a certain distance away from the polishing pad 7; then, the dressing unit 27 is placed in the circular through hole of the holder 24, and the dressing layer 274 and the active layer 273 are in direct contact with the surface of the polishing pad 7; then, the first hydraulic valve 261 is opened to connect the two hydraulic cylinders 26 in series, the second hydraulic valve 262 is opened to allow the hydraulic oil in the oil tank 263 to flow into the hydraulic cylinders 26, the telescopic rods of the hydraulic cylinders 26 are extended, and the lower ends of the telescopic rods of the hydraulic cylinders 26 are connected with the rigid layer 271, so that the rigid layer 271 is subjected to stable pressure, and further, a stable extrusion effect exists between the action layer 273 and the finishing layer 274 and the polishing pad 7, and the second hydraulic valve 262 is closed after a certain pressure is reached. Then the driving module 6 drives the polishing disk 4 to rotate through the transmission shaft 5, and the polishing pad 7 adhered on the polishing disk 4 also rotates along with the rotation, so that the polishing pad 7 generates a friction action with the action layer 273 and the trimming layer 274; meanwhile, the dressing liquid containing the micro particles outside is drained to a position between the polishing pad 7 and the contact part of the action layer 273 and the dressing layer 274, and as the action layer 273 has higher hardness and is positioned in front of the dressing layer 274, a stronger friction effect is generated between the action layer 273 and the polishing pad 7, so that the micro particles generate a scratching effect on the polishing pad 7, the holding force of the abrasive particles in the polishing pad 7 is reduced, and even the ineffective abrasive particles with smaller holding force can fall off; since the soluble substance 275 in the finishing layer 274 is soluble in water and the dissolution speed becomes larger with the increase of the temperature, pits with different sizes will appear on the surface of the finishing layer 274, and the tiny particles will wipe the pits, promote the dissolution of the soluble substance 275 and make the sizes of the pits larger; the abrasive grains with weakened holding force are embedded into the concave pits under the action of extrusion, so that the abrasive grains are effectively separated under the action of rotation of the polishing pad 7, and the separated abrasive grains flow out of the range of the polishing pad 7 along with the flowing of the dressing liquid; because the flatness of the failed polishing pad 7 is relatively good, the difference between the effective protrusion heights of the abrasive particles in the polishing pad 7 is not large, the width of the effective protrusion embedded in the pit is large, but the protrusion height of the effective abrasive particles re-exposed from the polishing pad 7 is increased along with the continuous falling of the failed abrasive particles, so that the width of the effective protrusion capable of cutting into the pit is reduced, the holding force of the pit on the abrasive particles is reduced, and the effective abrasive particles re-exposed from the polishing pad 7 cannot fall off again; however, the effective abrasive grains newly exposed from the polishing pad 7 have different projection heights, so that the flatness value of the polishing pad 7 is increased, the abrasive grains with larger projection heights can be embedded into the v-shaped through hole 277 in the trimming layer 274, under the holding action of the rotating polishing pad 7 and the v-shaped through hole 277, the abrasive grains can fall off, a part of the fallen abrasive grains can enter the rectangular groove of the flexible layer 272 through the v-shaped through hole 277, the difference between the effective projections of the effective abrasive grains is reduced, and the flatness of the polishing pad 7 is improved; when the failed polishing pad 7 is repaired, the ultrasonic sensor positioned at the left end of the retainer 24 detects the flatness of the polishing pad 7 in the repairing area, and the polishing pad 7 is stopped being repaired after the flatness of the polishing pad 7 meets the requirement, so that the efficient repairing of the failed polishing pad is realized, and the flatness of the repaired polishing pad is improved.

When the polishing machine works, the polishing pad 7 is firstly adhered to the polishing disc 4, then the motor 21 drives the lead screw 23 to rotate, the rotating lead screw 23 drives the retainer 24 to move downwards due to the fact that the right end of the retainer 24 is in threaded connection with the lead screw 23, and the motor 21 is powered off after the lower end of the retainer 24 and the polishing pad 7 reach a certain distance. The dressing unit 27 is then placed in the circular through-hole of the holder 24, and the dressing layer 274 and the active layer 273 are brought into direct contact with the surface of the polishing pad 7. Then, the first hydraulic valve 261 is opened to connect the two hydraulic cylinders 26 in series, the second hydraulic valve 262 is opened to allow the hydraulic oil in the oil tank 263 to flow into the hydraulic cylinders 26, the telescopic rods of the hydraulic cylinders 26 are extended, and the lower ends of the telescopic rods of the hydraulic cylinders 26 are connected with the rigid layer 271, so that the rigid layer 271 is subjected to stable pressure, and further, a stable extrusion effect exists between the action layer 273 and the finishing layer 274 and the polishing pad 7, and the second hydraulic valve 262 is closed after a certain pressure is reached. Then the driving module 6 drives the polishing disk 4 to rotate through the transmission shaft 5, and the polishing pad 7 adhered on the polishing disk 4 also rotates along with the rotation, so that the polishing pad 7 generates a friction action with the action layer 273 and the trimming layer 274; meanwhile, the dressing liquid containing the micro particles outside is drained to the position between the polishing pad 7 and the contact part of the action layer 273 and the dressing layer 274, and as the action layer 273 is higher in hardness and located in front of the dressing layer 274, a stronger friction effect is generated between the action layer 273 and the polishing pad 7, so that the micro particles generate a scratching effect on the polishing pad 7, the holding force of the abrasive particles in the polishing pad 7 is reduced, and even the ineffective abrasive particles with smaller holding force can fall off. Since the soluble substance 275 in the finishing layer 274 is soluble in water and the dissolution speed becomes larger with the increase of the temperature, pits with different sizes will appear on the surface of the finishing layer 274, and the tiny particles will wipe the pits, promote the dissolution of the soluble substance 275 and make the sizes of the pits larger; the abrasive grains with weakened holding force are embedded into the concave pits under the action of pressing, so that the abrasive grains are effectively separated under the action of rotation of the polishing pad 7, and the separated abrasive grains flow out of the range of the polishing pad 7 along with the flow of the dressing liquid. Because the flatness of the failed polishing pad 7 is relatively good, the difference between the effective protrusion heights of the abrasive particles in the polishing pad 7 is not large, the width of the effective protrusion embedded in the pit is large, but the protrusion heights of the effective abrasive particles exposed again from the polishing pad 7 are increased along with the continuous falling of the failed abrasive particles, the width of the effective protrusion capable of cutting into the pit is reduced, the holding force of the pit on the abrasive particles is reduced, and the effective abrasive particles exposed again from the polishing pad 7 cannot fall off again. However, the effective abrasive grains newly exposed from the polishing pad 7 have different projection heights, so that the flatness value of the polishing pad 7 is increased, the abrasive grains with larger projection heights are embedded into the v-shaped through holes 277 in the finishing layer 274, under the holding action of the rotating polishing pad 7 and the v-shaped through holes 277, the abrasive grains are separated, a part of the separated abrasive grains enter the rectangular grooves of the flexible layer 272 through the v-shaped through holes 277, the difference between the effective projections of the effective abrasive grains is reduced, and the flatness of the polishing pad 7 is improved. When the failed polishing pad 7 is repaired, the ultrasonic sensor at the left end of the retainer 24 detects the flatness of the polishing pad 7 in a repairing area, a detected signal is transmitted to the controller, the polishing pad 7 is stopped being repaired after the flatness of the repaired polishing pad 7 meets requirements, then a workpiece is placed on the polishing pad 7 and is polished under the action of the polishing module 3 and the rotating polishing disk 4, so that the phenomenon that the workpiece is insufficiently polished due to uneven height distribution of abrasive particles after the polishing pad 7 is repaired is avoided, more scratches are generated, the surface roughness of the polished workpiece is larger, the polishing pad 7 is effectively repaired, and the surface quality of the workpiece is improved.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.