JP2001062718A - Double head grinding device and grinding wheel position correcting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double head grinding device having a grinding wheel position corrector capable of accurately detecting a position of a workpiece into contact with a grinding wheel and detecting behavior of the workpiece during grinding, that is, its movement relating to a grinding wheel spindle direction and a grinding wheel position correcting method, for manufacturing a ground product of good accuracy (quality). SOLUTION: Displacement in a spindle direction of a cup type grinding wheel 1 of a thin type workpiece 2 held to a workpiece holder 3 in a double head grinding device is detected by a non-contact type sensor or eddy current sensor 9 mounted in the workpiece holder 3, based on the detected displacement in the spindle direction of the thin type workpiece 2, a position of both the cup type grinding wheels 1 is corrected to a position with the thin type workpiece 2 serving as the center.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin work, for example, glass for optical parts, semiconductor silicon wafer, CD,
The present invention relates to a grindstone position detecting and correcting mechanism and a grindstone position correcting method for a thin work in a double-headed grinding device for grinding both surfaces of a disk-shaped thin work such as a glass disk such as an MD.

[0002]

2. Description of the Related Art When one of two opposing cup-shaped grindstones contacts a thin work when grinding a thin work in a double-headed grinding machine, a load is applied to the thin work and the thin work is reduced. Since the work is elastically deformed in the direction opposite to the contact direction, that is, the thin work behaves in the axial direction, and the grinding accuracy of the work is reduced. Therefore, the work position and the positions of both spindles of the cup-shaped grindstone are important requirements for obtaining a product with high accuracy (quality).

Conventionally, the following methods (1) and (2) have been known as methods for finding the position of a work and the positions of both spindles of a cup-type grindstone. (1) A method of detecting contact between a work and a grindstone by an AE sensor (acoustic emission). (2) A method in which the positions of the grindstone and the work are respectively detected by various touch sensors, and the contact start position is estimated from the relative positions.

[0004]

However, according to the above method (1), in the case of a thin work, the work is elastically deformed even with a small force, so that the work inserted between the two grindstones is applied to the grindstone. The distance until the contact (contact start position) is not known accurately. In the method (2), there is a problem that the grindstone gradually wears out during the grinding process, so that the measurement is required each time, and an error is increased due to the indirect measurement. . Further, the methods (1) and (2) cannot detect the axial movement behavior of the workpiece during grinding.

In order to manufacture a product with high accuracy (quality), the double-headed grinding apparatus of the present invention accurately detects the position at which the work comes into contact with the grindstone, and detects the behavior of the work during grinding.
That is, an object of the present invention is to provide a double-head grinding apparatus and a grinding wheel position correction method having a grinding wheel position determiner capable of detecting a movement of a workpiece in the direction of a grinding wheel main axis.

[0006]

In order to solve the above-mentioned problems, a double-head grinding apparatus according to the present invention is provided for detecting a displacement of a work held in a work holding device of the double-head grinding apparatus in a grindstone main axis direction. A non-contact type sensor or an eddy current sensor is attached to the work holding device, and has a whetstone position determiner for correcting a whetstone position based on the displacement of the work detected by the non-contact type sensor or the eddy current sensor. I do.

Further, the method of correcting the position of a grinding wheel in a double-headed grinding apparatus according to the present invention is characterized in that the displacement of a work held in a work-holding apparatus of a double-headed grinding apparatus in the main axis direction of a work is controlled by a non-contact type The position of both grindstones is corrected to a position centered on the work based on the detected displacement of the work in the main axis direction detected by a sensor or an eddy current sensor.

In the method for correcting the position of a grinding wheel in a double-head grinding apparatus according to the present invention, it is preferable that the displacement of the workpiece in the main axis direction is continuously grasped.

[0009]

FIG. 1 is a side sectional view schematically showing a work holding device and a cup-type grindstone of a double-headed grinding device according to the present invention. FIG. 2 is a front view of the work holding device of FIG.

In FIGS. 1 and 2, reference numeral 1 denotes a cup-shaped grindstone, and a cup-shaped open-side end face has a flat grinding action surface 7.
It has become. Two cup-shaped grindstones 1 are paired, and the open sides face each other to form a horizontal double-headed grindstone. The double-headed cup-shaped grindstone 1 is held by a moving device (not shown) so that the distance between the grinding action surfaces 7 can be adjusted, and a driving device ( (Not shown) to form a grinding device capable of grinding both surfaces of the thin work 2.
The above-described grinding apparatus is suitable for grinding a thin work 2 that requires grinding on both sides.

Reference numeral 3 denotes an arched work holder for holding the thin work 2. Two holding pads 4 for holding both surfaces of the thin work 2 are fixed to both surfaces of the work holder 3. A plurality of static pressure forming portions 8 for applying a static pressure to both surfaces of the thin work 2 are provided on both inner surfaces of each press pad 4 in an island shape. Each static pressure forming part 8
By supplying a fluid such as a liquid or a gas as a lubricant under pressure, both surfaces of the thin work 2 are held at a fluid pressure. The work holder 3 includes a roller 5 for rotating the circumferential portion of the thin work 2 held by the static pressure forming unit 8 by friction and a driving source 6 for the roller 5.
Is provided.

Reference numeral 9 denotes a non-contact type sensor or an eddy current sensor which is attached to the work holder 3 and can measure a change in the position of the thin work 2. The attachment position of the non-contact sensor or the eddy current sensor 9 is preferably near the outer periphery of the thin work 2. In FIG. 1, two non-contact type sensors or eddy current sensors 9 are provided so as to oppose both sides of the thin work 2 and not to contact the thin work 2. This can be achieved at one location by using a method such as measuring the thickness of the thin work 2 in advance. However, it is preferable to provide two contactless sensors or eddy current sensors 9 because more reliable data can be obtained.

The operation of the double-headed grinding apparatus according to the present invention will be described below. Both surfaces of a part of the thin work 2 are held by the press pad portion 4 of the work holder 3, and the thin work 2 is rotated in contact with a roller 5 driven and rotated by a servo motor as a drive source 6. The thin work 2 set in the work holder 3 in this way reaches the grinding position of the double-headed grinding device, a hydraulic pressure is applied to the press pad 4, the thin work 2 is rotated by the driving roller 5, and both cup molds are rotated. The grindstone 1 is sent toward the thin work 2.

At this time, the thin work 2 and the cup-type grindstone 1 are not yet in contact with each other, and the non-contact sensor or the eddy current sensor 9
The distance between the workpiece and the thin work 2 is measured. Therefore, if the thin work 2 fluctuates in the axial direction, the output from the non-contact sensor or the eddy current sensor 9 changes. Since the thin work 2 is rotating, the difference in the thickness of the thin work 2 itself is as follows.
The same displacement pattern is given to the output for each rotation. Therefore, it is desirable to adjust the work holder 3 and the work drive system in advance so as to stabilize the pattern.

The feed of the two cup type grinding wheels 1 (spindle) is advanced,
If the grinding surface 7 of only one of the cup-shaped grindstones 1 comes into contact with the thin work 2, the load causes the thin work 2 to be elastically deformed in a direction opposite to the contact direction, and the non-contact sensor or eddy current sensor 9 Is changed and output. Next, the output value of the non-contact type sensor or the eddy current sensor 9 is input to the grindstone position determiner 10, and the cup-shaped grindstone 1 on one side is input.
Correct and determine the contact start point of. If the two cup-shaped grindstones 1 come into contact with the thin workpiece 2 at exactly the same time, the contact start position is not detected. This means that the center between the thin work 2 and the cup-shaped grindstone 1 was correct. After the contact start position of one cup-type grindstone 1 is determined, the cup-type grindstone 1 is retracted based on the determined value of the contact start position, and only the other cup-type grindstone 1 is advanced,
By measuring the contact start position in the same manner, the contact start position of both cup-type grindstones 1 is made correct. By monitoring the output of the sensor during grinding, the movement of the work in the direction of the grindstone main axis can be grasped.

[0016]

According to the double-head grinding apparatus and the grinding wheel position correcting method having the non-contact type sensor or the eddy current sensor of the present invention, the center between the two cup-shaped grinding wheels whose center in the thickness direction of the thin work is opposed to each other. Therefore, if the grinding is performed by correcting the contact start position of the two cup-shaped grindstones to the correct position by the double-ended grinding device of the present invention, the elastic deformation of the thin work is eliminated, and the ground surface is flat. Finished product with good accuracy (quality) can be obtained.

According to the double-head grinding apparatus and the grinding wheel position correcting method having the non-contact type sensor or the eddy current sensor of the present invention,
The grinding amount can be easily controlled.

According to the double-head grinding apparatus and the grinding wheel position correcting method having the non-contact type sensor or the eddy current sensor of the present invention,
Since the behavior of the thin work can be grasped, it is possible to predict the rough state of the working surface of the cup-type grindstone, insufficient rigidity of the work holding, etc.
It is possible to predict the dressing time of the grinding wheel and adjust the holding pressure.

[Brief description of the drawings]

FIG. 1 is a side sectional view schematically showing a work holding device and a cup-type grindstone of a double-headed grinding device according to the present invention.

FIG. 2 is a front view of the work holding device of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cup-type grindstone 2 Thin work 3 Work holder 4 Holding pad 5 Roller 6 Drive source 7 Grinding working surface 8 Static pressure forming part 9 Non-contact type sensor or eddy current sensor 10 Grinding wheel position determiner

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Isobe 63-30 Yuigaoka, Hiratsuka-shi, Kanagawa Sumitomo Heavy Industries Machinery Co., Ltd. (72) Inventor Kazunori Hara 63-30 Yuyogaoka, Hiratsuka-shi, Kanagawa Prefecture Sumitomo Heavy Industries Machinery Co., Ltd. Sumitomo Heavy Industries, Ltd. Niihama Works F-term (reference) 3C034 AA08 BB22 BB72 CA13 CB01 DD20 3C043 BC04 CC04 DD05 DD06 EE04

Claims (6)

[Claims] 1. A non-contact type sensor for detecting a displacement of a work held by a work holding device of a double-headed grinding machine in a grindstone main axis direction is attached to the work holding device. A double-headed grinding device comprising a grinding wheel position determiner for correcting a grinding wheel position based on a displacement. 2. An eddy current sensor for detecting displacement of a work held by a work holding device of a double-headed grinding device in a grindstone main axis direction is attached to the work holding device, and the displacement of the work detected by the eddy current sensor is provided. A double-head grinding device comprising a grindstone position determiner for correcting a grindstone position based on a grinding wheel. 3. A non-contact type sensor or an eddy current sensor attached to the work holding device detects a displacement of the work held in the work holding device of the double-headed grinding device in a main axis direction of the grindstone. A whetstone position correcting method, wherein the positions of both whetstones are corrected to a position where a work becomes a center based on an axial displacement. 4. The grinding wheel position correcting method according to claim 3, wherein the displacement of the workpiece in the axial direction is continuously grasped. 5. The grinding wheel position correcting method according to claim 3, wherein the grinding amount is controlled by continuously grasping the axial displacement of the work. 6. A method for predicting a rough state of a working surface of a grindstone, predicting a lack of rigidity of a work holding, and / or predicting a dressing time of a grindstone by continuously grasping an axial displacement of a work. The grinding wheel position correcting method according to claim 3, characterized in that: