JPH0679596A - Duplex head grinding machine - Google Patents

Abstract

PURPOSE:To provide the thickness processing precision in the 0.1mum range of a duplex head grinding machine, with a simple and low cost structure. CONSTITUTION:The distance between a lower side grinding wheel 15 whose position is fixed, and an upper side grinding wheel 18 which is attached to a magnetic bearing spindle 19 as being faced to the lower side grinding wheel 15, is coarsely controlled by the vertical motion of a cam follower 24, according to the rightward/leftward motion of a taper cam 22 made by using a ball screw 23. Moreover, both grinding wheels 15, 18 are positioned as the distance between them is adjusted in the 0.1mum range, by means of the adjusting function of the magnetic bearing spindle 19 itself. After that, a work is made to pass by means of a carrier 17 between bolt grinding wheels of both rotating spindles for performing double-side grinding and forming it into the fixed thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided grinder that grinds plate-like or columnar materials such as ceramic parts represented by piezoelectric elements at the same time on both sides.

[0002]

2. Description of the Related Art Ceramic parts having a thickness of 0.5 mm or less, such as piezoelectric elements, are formed into thin pieces by using a slicing machine. After molding, in order to obtain the electrical characteristics, both sides have been conventionally ground by a double-headed grinder as shown in FIG. 4 so that the thickness falls within a certain tolerance. That is, the space between the upper grindstone 1 and the lower grindstone 2 mounted on the spindle 4 which is fixed in advance is moved up and down by using the feed mechanism including the ball screw 5 and the slider 6 for the spindle 3 mounted with the upper grindstone 1. By setting the values, the respective spindles are rotated, and the grinding fluid is supplied during this period. When the components conveyed by the carrier 7 pass between the two grindstones one after another, they are ground to a constant thickness.

[0003]

However, in the case of such a structure, since the feed for setting the upper and lower grindstone intervals is on the order of 1 μm, it is possible to perform grinding with a thickness accuracy of 1 μm or less. There is a problem that it is impossible and it is difficult to control the change of the environment such as room temperature and the variation of the interval between the upper and lower grindstones due to the abrasion of the grindstone.
This is for the following reason.

That is, in order to obtain a feed accuracy of the order of 1 μm or less with the ball screw which constitutes the spindle notch mechanism, it is necessary to use a ball screw having a small pitch and a good feed linearity. However, in order to make the feed mechanism capable of withstanding fluctuations in processing pressure and large processing pressures in terms of accuracy, it is necessary to increase the diameter of the ball screw. Could not be in the 1 μm range.

Further, in order to obtain the rigidity of the entire grinding machine including the feed mechanism, when the upper and lower grindstone intervals are first set, the spindle is firmly fixed by a clamper on a slider which moves up and down. For this reason, it is difficult to change the interval once set during processing. The present invention aims to solve the above conventional problems.

[0006]

In order to achieve this object, a double-headed grinding machine of the present invention uses a spindle having a small cutting depth correction function of a grindstone instead of a conventional bearing bearing type spindle. It has a mechanism to hold the position by coarse feed of the entire spindle before cutting.

[0007]

[Operation] The operation of this configuration is as follows.

That is, by using the spindle itself having the function of correcting the minute depth of cut, the grindstone is reduced to 0.
Positioning is possible on the order of 1 μm, and the combination of a coarse-motion feed ball screw and a taper cam reduces the restrictions on the positioning accuracy due to coarse motion compared to the conventional grindstone feed mechanism with a single ball screw. Since a large diameter can be taken, high rigidity can be obtained in combination with the taper cam. In addition, the slider is fixed with a clamper after positioning by coarse feed, but since the spindle itself makes corrections in a highly rigid fixed state, it is possible to make minute cuts even during processing, depending on the processing state. It is possible to control the depth of cut. Further, it is possible to reduce the size by clamping the spindle during processing to increase the rigidity.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a spindle incorporating a micro-cutting correction mechanism of a double-head grinding machine according to an embodiment of the present invention. The rotor 12 installed in the gap formed by the spacer 11 sandwiched between the two stators 10,
The electromagnetic force of the coil 13 floats the stator 10. Shaft 14 mounted on rotor 12
Position is detected by the displacement sensor 15, and the current of the coil 13 is operated to control the position of the shaft 14. Position control can be performed on the order of 0.1 μm, and an example of a double-head grinding machine using a magnetic bearing spindle that incorporates this control as a fine cut correction mechanism is shown below.

FIG. 2 is a plan view showing the construction of a double-sided grinder in an embodiment of the present invention, and FIG. 3 is a front view of the same.

First, the bearing bearing spindle 16 having the lower grindstone 15 mounted thereon is fixed to the carrier 17 at an appropriate position. Next, the magnetic bearing spindle 19 on which the upper grindstone 18 is mounted is brought closer to the lower grindstone 15 by a ball screw 20 and a slider 21 so that the magnetic grindstone spindle 19 is moved to the left and right using the ball screw 23 of the taper cam 22. The interval is roughly adjusted by vertically moving the cam follower 24. After that, the magnetic bearing spindle 19 is fixed by the clamp 25 for improving the rigidity, and further, the interval is set on the order of 0.1 μm by using the minute cutting function of the spindle 19 itself. The holding force of this clamp 25 is a clamping force of 500 kg, μ = 0.1
Is 50 kg, and if the spindle's own weight is 30 kg,
It is possible to process up to 20kg of reaction force.

Then, the bearing bearing spindle 16
And rotating the magnetic bearing spindle 19 respectively,
While operating the carrier 17 while supplying the grinding fluid between the grindstones,
When a component to be processed is put in here, double-side grinding is performed when the component passes between the grindstones, and a constant thickness is formed. Further, according to the change in the room temperature or the processing time, it is possible to perform the positioning correction by the minute cutting function of the magnetic bearing spindle 19 and reduce the change in the thickness.

[0014]

As described above, according to the present invention, the spindle having the grindstone mounted therein has the minute cutting mechanism incorporated therein, and by using the mechanism for performing the coarse feed and maintaining the position of the entire spindle portion, it becomes simple and low in cost. With the configuration, it is possible to obtain a thickness processing accuracy on the order of 0.1 μm.

[Brief description of drawings]

FIG. 1 is a schematic view of a spindle incorporating a minute cutting mechanism of a double-sided grinder according to an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view of the same.

FIG. 4 is a perspective view of a conventional double-headed grinder.

[Explanation of symbols]

 1, 2, 15, 18 Grinding stone 7, 17 Carrier 3, 4, 16 Bearing bearing spindle 8 Motor (for driving spindle 3) 19 Magnetic bearing spindle 25 Clamp

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Takahashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A double-head grinding machine characterized in that at least one of two spindles equipped with a grindstone arranged to sandwich a workpiece in a vertical direction is provided with a fine cutting correction function. 2. A taper cam provided so as to move in a direction perpendicular to a cutting direction of the spindle, a ball screw for driving the taper cam, a means for driving the ball screw, and a mounting device mounted on the spindle. The double-head grinding machine according to claim 1, further comprising a cam follower that moves the spindle up and down while sliding on the taper cam.