JPS62107935A - Automatic correcting mechanism for surface grinder - Google Patents

Abstract

PURPOSE:To detect and correct an error in parallelism whenever there is any error by providing a sensor for detecting the inclination of a grinding wheel surface to a reference surface, and a sensor for detecting the inclination of a workpiece mounting surface to said reference surface. CONSTITUTION:Four non-contact type distance sensors 21 are provided opposite to the periphery of the top surface of an air spindle 3, i.e., the mounting surface of a workpiece 1. Sensors 21 are also provided opposite to the surface of a grinding wheel 14. And, by calculating the inclination of a workpiece mounting surface to a reference surface and the inclination of a wheel surface to the reference surface, the parallelism between the workpiece mounting surface and the wheel surface can be calculated based on the calculated values of the inclinations. Then, voltage is applied to a piezo-electric element 7 to control the posture of a table unit in the direction of making the parallelism between the workpiece mounting surface and the wheel surface zero.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device that automatically corrects the misparallelism between a grinding wheel surface and a workpiece mounting surface in a surface grinder.

[Prior art]

For precision grinding, a surface grinder has a workpiece mounting surface configured perpendicular to the rotation axis and a grinding wheel surface configured perpendicular to the rotation axis, parallel to the rotation axis, facing each other. The parallelism between the workpiece mounting surface and the grinding wheel surface must be maintained with high precision. However, since both of the rotating shafts are subjected to the reaction force of the grinding force in addition to the gravity load and the acceleration load, it is difficult to avoid slight deformation. Furthermore, thermal distortion occurs due to heat generated by the motor.

For this reason, simply increasing the rigidity of the shaft of one rotation or the pressure load of the bearing cannot improve the accuracy within the range of conventional technology, for example, for grinding products that require ultra-high precision such as semiconductor wafers. I had reached my limit.

In order to improve the parallelism between the grinding wheel surface and the workpiece mounting surface with even higher precision, automatic correction of the rotary shaft support direction is required.

In order to develop the above automatic correction mechanism, we needed (a) a mechanism that measures the parallelism of both surfaces during operation, and (b) an adjustment of the bearing direction of the rotating shaft based on the above measured values. (a) and (b) above.

Regarding item (b) of these, adjustment of the supporting direction of the rotary bearing, assume three orthogonal axes x, y, and z, and construct a table unit that supports the table axis in the Z-axis direction. The table unit and the sub-base are pivoted to the sub-base by an axis in the Y direction, and the sub-base is supported to the base member by an axis in the X-direction, and the table unit and the sub-base are rotated minutely around the Y-axis and the angle Δθ
.

The table is configured to rotate by Δφ to adjust the axial direction of the table shaft, and a piezoelectric element and a distance sensor are interposed between the table unit and the sub-base and between the sub-table and the base member, respectively. However, it is conceivable to control the voltage applied to the piezoelectric element to adjust the minute angles Δθ and Δφ, respectively.

The above configuration is an invention created by the present inventor and filed separately (
(hereinafter referred to as the device of the prior application). FIG. 4 is an explanatory diagram of the adjusting device of the prior application.

In FIG. 1, a workpiece 1 is vacuum-adsorbed onto a rotating chuck table 2. As shown in FIG. 3 is an air spindle that rotates the chuck table 2.

The table unit 4 supporting the air spindle 3 has one end pivoted to the sub-base 11 by a hinge pin 9 in the Y-axis direction as a fulcrum for fine adjustment, and the other end is a piezoelectric element 9 which is an actuator for fine adjustment. and is fastened with bolts 24.

The above sub-base 11 is pivoted to the base member 12 by a hinge pin 8 in the X-axis direction, and is fastened with a bolt z5 via a piezoelectric element IO. 13 is a surface plate.

A head 16 is guided up and down by a guide member 19 of a column 18. This head 16 is provided with an air spindle 17 extending in the Z-axis direction, and supports the grindstone 14 via a rotating disk 15 parallel to the xy plane.

According to the device of this earlier application (FIG. 4), the piezoelectric element 7.10
When a voltage is applied to expand and contract the table unit 4, the table unit 4 is rotated by a small angle around the hinge pin 9.8, and the grinding wheel 14 is rotated so that the mounting surface of the workpiece 1 is parallel to the X-Y plane. It can be adjusted so that it is parallel to the bottom surface of.

[Problem that the invention seeks to solve]

In order to demonstrate the practical value of the device of the earlier application (Fig. 4), it is necessary to use the mechanism (a) mentioned above, that is, a mechanism that can detect the parallelism between the mounting surface of the workpiece and the grinding wheel surface during operation. development is desperately needed. The object of the present invention is to meet this need.

[Means for solving problems]

In order to achieve the above object, the correction mechanism of the present invention is as follows.

In a surface grinding machine in which a workpiece mounting surface configured perpendicularly to a rotating shaft and a grinding wheel surface configured perpendicularly to the rotating shaft provided parallel to the rotating shaft face each other, the workpiece mounting surface and a reference plane parallel to the grinding wheel surface, a sensor for detecting the inclination of the grinding wheel surface with respect to the reference plane, and a sensor for detecting the inclination of the workpiece mounting surface with respect to the reference plane, and both of the above. An automatic calculation device is provided to calculate the inclination angle between the grinding wheel surface and the workpiece mounting surface by inputting the detection signal of the sensor, and the supporting direction of the rotary shaft is set on at least one of the two rotary shafts. The present invention is characterized in that an adjusting device is provided, and a control means is provided for automatically operating the adjusting device in a direction to make the inclination angle zero.

[Embodiment] Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a sectional view showing one embodiment of the present invention.

This embodiment is an example in which the present invention is applied and improved to the device of the previous application shown in FIG. 4, and FIG. 1 in this embodiment is as follows.
This figure depicts a portion corresponding to the 1-1 cross section of the device of the prior application (FIG. 1).

FIG. 2 is a side view of FIG. 1 as viewed in the direction of the arrow ■.

FIG. 3 is a plan view schematically drawn to explain the relative position between the chuck table 2 holding the workpiece 1 by suction and the disc 15 to which the grindstone is attached.

In this embodiment, a plane parallel to the X-Y plane is used as a reference plane.

As shown in FIG. 1, it is opposed to the periphery of the top surface of the air spindle 3 (the mounting surface of the workpiece 1).

Four non-contact distance sensors 21 (two sides are shown in FIG. 1) are provided. 22 is an arm for supporting the sensor, 2
3 is also amba.

7 is the piezoelectric element explained in FIG. 4, and 20 is a digital micro.

The detection output signal of the sensor 21 is inputted to a central control device (both not shown) via automatic calculation means.

Calculate the inclination of the workpiece mounting surface with respect to the reference surface.

As shown in FIG. 2, a sensor 21 is provided facing the surface of the grinding wheel 14, similar to the configuration described above (FIG. 1). In this example, the sensor 21 is opposed to the mounting surface of the grindstone 14. In this way, the inclination of the surface of the grindstone 14 with respect to the reference plane is calculated.

By calculating the inclination of the workpiece attachment surface with respect to the reference plane and the inclination of the grindstone surface with respect to the reference plane, the parallelism between the workpiece attachment surface and the grindstone surface can be calculated based on the calculated values.

Therefore, a voltage is applied to the piezoelectric element 7.10 (FIG. 4) described above to control the attitude of the table unit 4 in a direction that brings the parallelism of both surfaces to zero.

21 shown with a black circle in FIG. 4 and 21 shown with a broken line are:
Each shows the location where the sensor is installed. Point 0 is the center of rotation of the air spindle 3, and the circumference of the grindstone 14 attached to the disc 15 is configured to pass through the above point 0.

〔Effect of the invention〕

As explained above, according to the automatic correction mechanism of the present invention, the parallelism between the workpiece mounting surface and the grinding wheel surface in a surface grinding machine can be detected in the operating state. By applying this method, the parallelism can be automatically controlled, which greatly contributes to improving the machining accuracy of surface grinders.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of one embodiment of the present invention, and FIG.
It is a view in the direction of the ■ arrow in the figure. FIG. 3 is an explanatory diagram of the arrangement of sensors. FIG. 4 is a partially cutaway perspective view of the device of the prior application. 1...Workpiece, 2...Chuck table, 3...
・Air spindle, 14... Grindstone, 15... Disc, 21... Sensor, 22... Amber, 13...
Surface plate.

Claims (1)

[Claims] In a surface grinder in which a workpiece mounting surface configured perpendicularly to a rotating shaft and a grinding wheel surface configured perpendicularly to the rotating shaft provided parallel to the rotating shaft face each other, the workpiece mounting surface and a reference plane parallel to the grinding wheel surface, a sensor for detecting the inclination of the grinding wheel surface with respect to the reference plane, and a sensor for detecting the inclination of the workpiece mounting surface with respect to the reference plane, and both of the above. An automatic calculation device is provided to calculate the inclination angle between the grinding wheel surface and the workpiece mounting surface by inputting the detection signal of the sensor, and the supporting direction of the rotary shaft is set on at least one of the two rotary shafts. An automatic correction mechanism for a surface grinder, characterized in that an adjusting device is provided, and a control means is provided for automatically operating the adjusting device in a direction to make the inclination angle zero.