Polishing apparatus

Abstract

A polishing apparatus includes a polishing device for polishing a baseboard, a feeding device for transporting it to the polishing device and a discharging device for discharging the polished baseboard from the polishing device. The baseboard is clamped in one direction between rollers of the feeding device and is transported upwards while polishing tapes are run and backup members for pressing the polishing tapes to the baseboard undergo reciprocating motions in a perpendicular direction to polish both surfaces of the baseboard. The polished baseboard is transported further upwards, being clamped between rollers of the discharging device.

Description

BACKGROUND OF THE INVENTION

[0001] This invention relates to a polishing apparatus for polishing a planar target object.

[0002] Wiring chips having a wiring pattern formed through an insulating material are recently incorporated in small electronic devices such as portable telephones. Such wiring chips are obtained by repeating for a required number of times the sequence of operations including printing a specified wiring pattern on the surface of a resin film by a masking method, forming a uniform insulating resin membrane to obtain a flexible printed baseboard with an insulating membrane, polishing the surface of this printed baseboard, and thereafter cutting this printed baseboard.

[0003] This polishing process is for the purpose of matching the height of the insulating resin membrane with that of the wiring such that the surface of the printed baseboard will be flat. It used to be carried out by providing a polishing roller having a hard ceramic film with many small holes (about 50 &mgr;m in diameter) on the surface disposed around a rubber roller and directly pushing it against the target surface of the printed baseboard. This is often referred to as the buffing process. By this process, however, the surface of the polishing roller becomes degraded either locally or as a whole and the holes become clogged as the polishing process continues over an extended period of time and it soon becomes impossible to polish the target surface uniformly. Moreover, the finished surfaces of target objects may become different from one object to another, adversely affecting the reproducibility. In other words, polishing rollers must be replaced frequently after a relatively short time of use, and this tends to reduce the throughput.

SUMMARY OF THE INVENTION

[0004] It is therefore an object of this invention to provide a polishing apparatus capable of carrying out a polishing process over an extended length of time with improved reproducibility.

[0005] A polishing apparatus embodying this invention, with which the above and other objects can be accomplished, may be described as comprising a polishing device for polishing a baseboard, a feeding device for feeding the baseboard into the polishing device and a discharge device for discharging a polished baseboard from the polishing device. The polishing device includes a first polishing head and a second polishing head, each comprising a tape feeding means for feeding a polishing tape, a winding means for winding up the polishing tape, a backup member for pushing the polishing tape fed from the tape feeding means to the baseboard, and a reciprocating means for causing the backup member to undergo a reciprocating motion in a forward-backward direction. The first and second polishing heads are structured symmetrically in a right-left direction and disposed opposite each other. The polishing device serves to polish the baseboard by clamping it between the polishing tapes of the first and second polishing heads through their backup members and causing each of the backup members to undergo a reciprocating motion in the forward-backward direction. The backup members are provided with a pressure varying means for locally varying pressure applied on the baseboard by the feeding tapes. The pressure varying means may be characterized as including a plurality of indentations on a surface of each of the backup members and a nozzle for emitting pressurized air therefrom disposed in each of these indentations.

[0006] The feeding device comprises a first feeder and a second feeder which are structured symmetrically in the right-left direction, each comprising a feeder frame, a plurality of feeder rollers rotatably attached to the feeder frame for transporting the baseboard, and a feeder driving means for causing these feeder rollers to rotate. The first and second feeders are disposed such that corresponding ones of their feed rollers are opposite each other. The feeding device serves to transport the baseboard by clamping it between the oppositely facing feeder rollers and causing them to rotate by the feeder driving means.

[0007] The discharge device comprises a first discharger and a second discharger which are structured symmetrically in the right-left direction, each comprising a discharger frame, a plurality of discharger rollers rotatably attached to the discharger frame for transporting the baseboard, and a discharger driving means for causing these discharger rollers to rotate. The first and second dischargers are disposed such that corresponding ones of their discharger rollers are opposite each other. The discharging device serves to discharge the baseboard by clamping it between the oppositely facing discharger rollers and causing them to rotate by the discharger driving means.

[0008] When a baseboard is to be polished, it is disposed firstly between the first and second feeders and each feeder, each polishing head and each discharger is moved in the right-left direction such that the baseboard is clamped between the feeders while corresponding ones of the rollers of the feeders and the dischargers as well as the polishing heads are moved closer towards each other. Next, the feeder rollers are rotated such that the baseboard is transported upwards while the polishing tapes are transported and the backup members are caused to undergo reciprocating motions in the forward-backward direction such that both surfaces of the baseboard are polished. An upper part of the polished baseboard is clamped between the discharger rollers, and the baseboard is transported further upward with the rotations of the discharger rollers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a front view of a polishing apparatus embodying this invention.

[0010] FIG. 2 is a front view of the feeding device of the polishing apparatus of FIG. 1.

[0011] FIG. 3 is a front view of the polishing device of the polishing apparatus of FIG. 1.

[0012] FIG. 4 is a front view of the discharging device of the polishing apparatus of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. 1.

[0013] FIG. 6 is a sectional view taken along line 6-6 of FIG. 5.

[0014] FIGS. 7(a) and 7(b) are sectional views taken respectively along lines 7(a)-7(a) and 7(b)-7(b) of FIG. 3.

[0015] FIG. 8 is a sectional view taken along line 8-8 of FIG. 5.

[0016] FIG. 9(a) is a view of the surface of a backup member, and FIG. 9(b) is a partially sectional view of the backup member.

DETAILED DESCRIPTION OF THE INVENTION

[0017] The invention is described next by way of an example. FIG. 1 shows a polishing apparatus 10 embodying this invention, comprising a polishing device 30 for polishing a baseboard, a feeding device 20 for feeding the baseboard into the polishing device 30 and a discharge device 70 for discharging a baseboard from the polishing device 30. These constituent devices are arranged inside a housing 11.

[0018] The feeding device 20 comprises, as shown in FIG. 2, a first feeder 21 and a second feeder 21′, each including a plurality of rollers (or “feeder rollers”) 22a-22g (or 22a′-22g′) for transporting a baseboard, a frame (or “feeder frame”) 23 (or 23′) which supports the rollers 22a-22g (or 22a′-22g′) rotatably and a driving means (or “feeder driving means” (not shown)) for causing the rollers to rotate. The first and second feeders 21 and 21′ are disposed symmetrically in the right-left direction (with reference to the figure) such that corresponding ones of their rollers 22a-22g and 22a′-22g′ are opposite each other. The feeding of a baseboard is effected with the baseboard clamped between the mutually oppositely facing pairs of rollers 22a-22g and 22a′-22g′ and by rotating the rollers 22a-22g and 22a′-22g′ by the driving means. The driving means may comprise, for example, ball screws arranged vertically, each engaging a screw groove provided at an edge portion of a corresponding one of the rollers 22a-22g and 22a′-22g′ and means for rotating these ball screws.

[0019] The feeding device 20 also includes a feeder moving means for moving the first and second feeders 21 and 21′ towards or away from each other such that a baseboard can be clamped between the pairs of rollers 22a-22g and 22a′-22g′. The moving means includes guides 24 and 24′ formed respectively on the frames 23 and 23′ and actuators 26 and 26′ affixed to the housing 11. The guides 24 and 24′ are respectively engaged with rails 25 and 25′ affixed to the housing 11 so as to move along the rails 25 and 25′ as the actuators 26 and 26′ are activated.

[0020] The polishing device 30 comprises, as shown in FIG. 3, a first polishing head 31 and a second polishing head 31′, each including a tape feeding means for feeding a polishing tape T (or T′), a winding means for winding up the polishing tape T (or T′), a backup member 40 (or 40′) for pushing the polishing tape T (or T′) to the baseboard and a reciprocating means for causing the backup member 40 (or 40′) to undergo a reciprocating motion in a forward-backward direction (with reference to the figure and perpendicular to the right-left direction). The first and second polishing heads 31 and 31′ are disposed symmetrically and opposite to each other. The baseboard is polished thereby as it is clamped between the polishing tapes T and T′ on the surfaces of the polishing heads 31 and 31′ and the backup members 40 and 40′ are caused to undergo reciprocating motions in the forward-backward direction. The polishing device 30 is also provided with a head-driving means for moving the polishing heads 31 and 31′ towards and away from each other such that a baseboard can be clamped between their backup members 40 and 40′. Like the moving means for the feeding device 20, the head-driving means includes guides 35 and 35′ on the frames 34 and 34′ and actuators (shown at 37 and 37′ in FIG. 6) affixed to the housing 11. The guides 35 and 35′ engage with rails 36 and 36′ such that the polishing heads 31 and 31′ travel in the right-left direction along the rails 36 and 36′ as the actuators 37 and 37′ are activated.

[0021] The tape feeding means and the winding means respectively include tape rolls 32 and 32′ rotatably affixed to top parts of the frames 34 and 34′ and windup rollers 33 and 33′ rotatably affixed to bottom parts of the frames 34 and 34′. There are also included motors (shown at 38′ in FIGS. 5 and 7) for rotating the tape rolls 32 and 32′ and the windup rollers 33 and 33′. The speed of travel of the polishing tapes T and T′ can be varied by adjusting the speeds of rotation of the tape rolls 32 and 32′ and the windup rollers 33 and 33′. The tape rolls 32 and 32′ and the windup rollers 33 and 33′ are each removably attached to the frame 34 or 34′. As soon as the polishing tape T or T′ is completely wound up by the windup roller 33 or 33′, a new tape roll in a cartridge form can be installed and the windup roller 33 or 33′ which has wound up the completed polishing tape T or T′ is replaced by a new windup roller.

[0022] The polishing tapes T and T′ may be of any hitherto known types such as a tape having a polishing layer with abrading particles affixed with a resin binder formed on the surface of a plastic film, a tape with a layer of a foamed material formed on the surface of a plastic film, a tape with hairs of plastic fibers planted on the surface of a plastic film, a woven tape or an unwoven tape.

[0023] As shown in FIGS. 6 and 8, the reciprocating means for causing the backup members 40 and 40′ to undergo a reciprocating motion is attached to the frames 34 and 34′ so as to be rotatable therethrough, comprising shafts 41, 41′, 43 and 43′ and a shaft driving means (shown at 50 in FIG. 8) for causing these shafts 41, 41′, 43 and 43′ to rotate. These shafts 41, 41′, 43 and 43′ each have an eccentric part 42, 42′, 44 or 44′ which is displaced from the central axis of the corresponding one of the shafts 41, 41′, 43 and 43′. Each of these eccentric parts 42, 42′, 44 or 44′ is inserted into an opening provided at one end part of one of the backup members 40 and 40′ such that the backup members 40 and 40′ will undergo a reciprocating motion in the forward-backward direction as the shafts 41, 41′, 43 and 43′ are caused to rotate.

[0024] As shown in FIG. 8, the shaft driving means 50 for rotating the shafts 41, 41′, 43 and 43′ connected to the eccentric parts 42, 42′, 44 or 44′ comprises a motor 51 which is affixed to a shelf 12 of the housing 11, a cross-sectionally polygonal shaft 52 rotatably supported on the shelf 12 through brackets 53 and pulleys 54, 55 and 55′ each having an opening with a shape matching the cross-sectional shape of the shaft 52 and being penetrated by the shaft 52 therethrough. As the motor 51 is activated, the shaft 52 begins to rotate through a belt 56. As a result, shafts 43 and 43′ rotate through the pulleys 55 10 and 55′, belts 57 and 57′ and pulleys 47 and 47′ affixed to end parts of the shafts 43 and 43′, thereby causing the backup members 40 and 40′ to undergo a reciprocating motion, as described above and shown in FIGS. 6-8. The shaft 52 is disposed parallel to the rails 36 and 36′ such that each of the polishing heads 31 and 31′ moves in the right-left direction along the shaft 52 as the actuators 37 and 37′ are activated.

[0025] As shown in FIG. 3, the polishing device 30 is further provided with a distortion preventing means 60 for preventing the polishing tapes T and T′ from becoming distorted by the reciprocating motion of the backup members 40 and 40′. The distortion preventing means 60 includes rollers 61a-61d and 61a′-61d′ which are rotatably arranged on both the upper and lower sides of the backup members 40 and 40′ so as to undergo the same reciprocating motion with the backup members 40 and 40′. As shown in FIGS. 3, 7 and 8, these rollers 61a-61d and 61a′-61d′ are supported rotatably by cross-sectionally U-shaped frames 62 and 62′ provided with openings 63 and 63′ on both sides. Eccentric parts at the tips of shafts 64a-64d and 64a′-64d′ having the same cross-sectional shape as aforementioned shafts 41, 41′, 43 and 43′ are inserted into these openings 63 and 63′ such that, as the motor 51 is activated, the rollers 61a-61d and 61a′-61d′ undergo a reciprocating motion in the forward-backward direction through the belts 57 and 57′ and the pulleys 65 and 65′ together with the backup members 40 and 40′.

[0026] Each of the backup members 40 and 40′ (only the member 40 being shown in FIG. 9(a)) is provided with a plurality of indentations 48 on its surface, each of the indentations 48 containing therein a nozzle 49 for emitting pressurized air. The amount of pressurized air to be emitted through each nozzle 49 is electronically controlled individually such that the pressure with which the polishing tapes T and T′ are pressed against the baseboard can be varied locally.

[0027] The discharging device 70 comprises, as shown in FIG. 7, a first discharger 71 and a second discharger 71′, each including a plurality of rollers (or “discharger rollers”) 72a-72h (or 72a′-72h′) for transporting a baseboard, a frame (or “discharger frame”) 73 (or 73′) which supports the discharger rollers 72a-72h (or 72a′-72h′) rotatably and a driving means (or “discharger driving means” (not shown)) for causing the discharger rollers to rotate. The first and second feeders 71 and 71′ are disposed symmetrically in the right-left direction such that corresponding ones of their rollers 72a-72h and 72a′-72h′ are opposite each other. The discharge of a baseboard is effected with the baseboard clamped between the mutually oppositely facing pairs of rollers 72a-72h and 72a′-72h′ and by rotating the rollers 72a-72h and 72a′-72h′ by the driving means. The driving means may comprise, similar to the driving means for the aforementioned feeding device 20, ball screws arranged vertically, each engaging a screw groove provided at an edge portion of a corresponding one of the rollers 72a-72h and 72a′-72h′ and means for rotating these ball screws.

[0028] The discharging device 70 also includes a discharger moving means for moving the first and second dischargers 71 and 71′ towards or away from each other such that a baseboard can be clamped between the pairs of rollers 72a-72h and 72a′-72h′. The discharger moving means includes guides 74 and 74′ formed respectively on the frames 73 and 73′ and actuators 76 and 76′ affixed to the housing 11. The guides 74 and 74′ are respectively engaged with rails 75 and 75′ affixed to the housing 11 so as to move along the rails 75 and 75′ in the right-left direction as the actuators 76 and 76′ are activated.

[0029] When a baseboard is to be polished, both methods with fixed abrading particles and free abrading particles may be used. The former method is carried out by using polishing tapes each with abrading particles affixed to a surface. The latter method is carried out by providing a polishing slurry with abrading particles dispersed inside water or a water-based aqueous solution and supplying it to the boundary surfaces between polishing tapes and the surfaces of the baseboard.

[0030] The baseboard to be polished is initially placed on a plurality of guide rollers 13 (shown in FIG. 1) arranged on the bottom surface of the housing 11 in the forward backward direction and the actuators 26, 26′, 37, 37′, 76 and 76′ are activated so as to move the first and second feeders 21 and 21′, the first and second polishing heads 31 and 31′ and the first and second dischargers 71 and 71′ towards each other in the right-left direction such that the feeder rollers 22a-22g and 22a′-22g′ of the first and second feeders 21 and 21′, the discharger rollers 72a-72h and 72a′-72h′ of the first and second dischargers 71 and 72′, and the backup members 40 and 40′ of the first and second polishing heads 31 and 31′ will approach each other onto the vertical plane above the guide rollers 13.

[0031] Next, the feeder rollers 22a-22g and 22a′-22g′ of the feeding device 20 are rotated to transport the baseboard upward. While the polishing tapes T and T′ are run, the backup members 40 and 40′ are moved reciprocatingly in the forward-backward direction such that both surfaces of the baseboard are polished. The polished baseboard has its upper end clamped between the discharger rollers 72a-72h and 72a′-72h′ of the discharging device 70 and is transported further upward by the rotation of the discharger rollers 72a-72h and 72a′-72h′. Thus completes the polishing operation by the polishing apparatus 10 of this invention.

[0032] With a polishing apparatus thus structured, unused portions of polishing tapes are continuously supplied to the target surfaces to be polished. Thus, overall or local degradation of the tape surface while the tape is being used or the aforementioned problem of clogging can be obviated. Moreover, since the pressure on the tape surface can be locally varied, target surfaces can be polished extremely uniformly. The reproducibility of the target surfaces is thus improved, and the throughput can be increased.

Claims

1. A polishing apparatus comprising a polishing device for polishing a baseboard, a feeding device for feeding the baseboard to said polishing device and a discharge device for discharging the baseboard from said polishing device;

wherein said polishing device comprises a first polishing head and a second polishing head which are structured symmetrically in a right-left direction and disposed opposite each other and each comprise:

a tape feeding means for feeding a polishing tape;

a winding means for winding up said polishing tape;

a backup member for pushing the polishing tape fed from said tape feeding means to the baseboard; and

a reciprocating means for causing said backup member to undergo a reciprocating motion in a forward-backward direction which is perpendicular to said right-left direction;

said polishing device serving to polish the baseboard by clamping said baseboard between the polishing tapes of said first polishing head and said second polishing head through the backup members of said first polishing head and said second polishing head and causing each of the backup members to undergo a reciprocating motion in said forward-backward direction, said backup members having pressure varying means for locally varying pressure applied on said baseboard by said feeding tapes;

wherein said feeding device comprises a first feeder and a second feeder which are structured symmetrically in said right-left direction and each comprise a feeder frame, a plurality of feeder rollers rotatably attached to said feeder frame for transporting the baseboard, and a feeder driving means for causing said feeder rollers to rotate;

said first feeder and said second feeder being disposed such that corresponding ones of the feeder rollers of said first feeder and said second feeder are opposite each other; and

said feeding device serving to transport the baseboard by clamping the baseboard between the oppositely facing feeder rollers and causing said feeder rollers to rotate by said feeder driving means;

wherein said discharge device comprises a first discharger and a second discharger which are structured symmetrically in said right-left direction and each comprise a discharger frame, a plurality of discharger rollers rotatably attached to said discharger frame for transporting the baseboard, and a discharger driving means for causing said discharger rollers to rotate;

said first discharger and said second discharger being disposed such that corresponding ones of the discharger rollers of said first discharger and said second discharger are opposite each other; and

said discharging device serving to discharge the baseboard by clamping the baseboard between the oppositely facing discharger rollers and causing said discharger rollers to rotate by said discharger driving means.

2. The polishing apparatus of claim 1 wherein said pressure varying means includes a plurality of indentations on a surface of each of said backup members and a nozzle for emitting pressurized air therefrom disposed in each of said indentations.

3. The polishing apparatus of claim 2 wherein the amount of said pressurized air to be emitted through each of said nozzle is electronically controlled individually.

4. The polishing apparatus of claim 1 wherein said polishing device further comprises a head moving means for moving said first polishing head and said second polishing head in said right-left direction towards and away from each other, serving to clamp the baseboard between the backup members by moving said first polishing head and said second polishing head in said right-left direction;

wherein said feeding device further comprises a feeder moving means for moving said first feeder and said second feeder in said right-left direction towards and away from each other, serving to clamp the baseboard between the feed rollers of said first feeder and said second feeder by moving said first feeder and said second feeder in said right-left direction; and

wherein said discharging device further comprises a discharger moving means for moving said first discharger and said second discharger in said right-left direction towards and away from each other, serving to clamp the baseboard between the feed rollers of said first discharger and said second discharger by moving said first discharger and said second discharger in said right-left direction.