JPS6332592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus that automatically determines the optimum polishing direction for a material whose polishing efficiency varies depending on the polishing direction.

Among hard and brittle materials, there are many materials whose polishing efficiency differs depending on the polishing direction. If the crystalline shape of these materials is clear, it is possible to identify the direction in which the polishing efficiency will increase, but if the crystalline shape is unclear, the direction in which the polishing efficiency will increase must be found through trial and error. However, it was extremely difficult.

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art,
It is an object of the present invention to provide a polishing device that can easily determine the polishing direction in which the polishing efficiency is maximized regardless of whether the crystal form of the material is clear or not.

Focusing on the force acting on the contact surface (polishing surface) between the workpiece and the grindstone, when polishing efficiency is good, the polishing surface normal force is large and the polishing surface normal force is relatively small.
Furthermore, it is empirically known that when the polishing efficiency is poor, the polishing surface linear force decreases and the polishing surface normal force becomes relatively large.

Therefore, if constant load polishing is performed, the normal force to the polished surface becomes constant, so it is possible to determine the magnitude of the polishing efficiency by measuring only the magnitude of the linear force to the polished surface. The present invention focuses on this polishing surface linear force, and if the polishing surface linear force is large, the machining energy consumed per unit time is large. In other words, the machining removal efficiency is high.

Therefore, in the present invention, we focus on the electromotive force, vibration, acoustic emission (AE) generated on the polished surface, and the amount of deflection of the workpiece holding part as physical quantities corresponding to the linear force of the polished surface, and polishing is performed based on the magnitude of these physical quantities. This is an attempt to determine the size of efficiency.

An embodiment of the present invention will be described below with reference to FIG. A workpiece 1 is held by a holder 3, which is driven in the rotation direction by a motor 4, and a rotation angle is detected by a rotary encoder 5. These workpiece support systems are pressed against the rotating grindstone 11 by springs 6, and vibrations are absorbed by the springs. Further, the workpiece support system is fixed to the bar 9 via a bearing, and is in a flat position at the counterweight 10 and the fulcrum 8, and by adjusting the position or weight of the counterweight 10, the polishing pressure of the workpiece can be adjusted.

The case of measuring the electromotive force generated on the polished surface with reference to FIG. 1 will be explained. If both the workpiece 1 and the grinding wheel 11 are conductive, the conductive holder 3 and the grinding wheel main shaft 12
A measurement impedance (Z ₁ ) 15 is connected between the contact point 14 provided at the end, and the voltage detected at both ends is amplified by an amplifier 17, and further a signal processing circuit (filter, rectifier circuit, etc.) 18 is connected. detection output
You can get Vout. As another method of connecting this measuring impedance, it can also be connected between the holder 3 and the polishing disk main body 13 like the impedance (Z ₂ ) 16. When the workpiece 1 is driven by the motor 4 in the direction of the rotation angle as shown in Fig. 4 while detecting the detection output Vout (β: constant), the detection output Vout with respect to the rotation angle becomes, for example, as shown in Fig. 5. It changes to , and has a local maximum value and a local minimum value. These local maximum values and local minimum values can be easily determined by the microcomputer 20, and the workpiece rotation angle at that time is input from the rotary encoder 5 and stored. As a result, for example, in Fig. 5, the workpiece rotation angle showing the maximum value is
It can be determined that angles of 90° and 270° are directions in which the polishing efficiency increases, and angles of 180° and 360°, which show minimum values, are directions in which the polishing efficiency decreases.

Apart from the above-mentioned work rotation mechanism, the polishing direction of the work can also be changed by rotating the work 1 in the circumferential direction of the grindstone 11 while keeping α constant as shown in FIG. 4 and changing the angle β. Can be done.

When the workpiece 1 is non-conductive, the conductive holder 3 is extended to the polishing surface of the workpiece so that the workpiece and the holder can be polished simultaneously, and the electromotive force between the holder and the grindstone can be detected by the method shown in FIG. In this case, in the direction where the workpiece polishing efficiency is high, the polishing efficiency of the holder 3 is also high, so the detection output Vout
is a large value, and in the direction where the polishing efficiency of the workpiece is small, the polishing efficiency of the holder 3 is also small, so the detection output Vout is a small value, and it can be seen that the determination can be made in the same way.

Alternatively, when the workpiece 1 is non-conductive, a method may be adopted in which the workpiece is fixed with a conductive shank 2 and the shank is fixed to a conductive holder 3 as shown in FIG. Although FIGS. 2 and 3 have been described assuming that the workpiece is non-conductive, the invention can also be applied when the workpiece is conductive.

The case of detecting the electromotive force on the polishing surface has been described above, but in addition to the electromotive force, there are other physical quantities corresponding to the polishing force, such as the amount of deflection of the workpiece holder, vibration of the polishing surface, and acoustic emission.
By detecting these as detection outputs, it is also possible to similarly find the direction of high polishing efficiency from the output characteristics as shown in FIG. In order to detect these physical quantities, as shown in FIG. Judgment can be made.

According to the present invention, even if the crystal shape of the workpiece is not clear, it is possible to easily find the direction in which the polishing efficiency is maximized, and for example, it is possible to improve the polishing efficiency of hard brittle materials such as diamond.

[Brief explanation of the drawing]

FIG. 1 shows the structure of a polishing apparatus to which the determination device of the present invention is applied, FIG. 2 shows an example of a holder for a non-conductive workpiece, FIG. 3 shows another example of a holder for a workpiece, and FIG. FIG. 4 is an explanatory diagram of a method of adjusting the polishing direction by rotating the workpiece, and FIG. 5 is a waveform diagram showing an example of a detected output of a physical quantity corresponding to the polishing force accompanying the rotation angle of the workpiece. 1...Work, 2...Shank, 3...Holder, 4...
Motor, 5...Rotary encoder, 6...Spring, 7
...transducer, 8...fulcrum, 9...bar, 10
...Counterweight, 11...Whetstone, 12...Main shaft,
DESCRIPTION OF SYMBOLS 13... Polishing machine main body, 14... Contact, 15, 16... Impedance for measurement, 17... Amplifier, 18... Signal processing circuit, 19... Power supply for motor drive, 20... Micro computer.

Claims (1)

[Scope of Claims] 1. A measuring impedance is connected between the workpiece and the grindstone support, and by detecting the potential difference between both ends of the measuring impedance, the polishing surface of the workpiece or the grindstone surface is adjusted by polishing. comprising a detection circuit for detecting the generated electromotive force, means for rotating the workpiece relative to the grinding wheel surface so that the polishing direction of the workpiece changes, and means for detecting the polishing direction in which the electromotive force takes an extreme value, An apparatus for automatically determining an optimum polishing direction, characterized in that the polishing direction that takes the extreme value is determined to be the direction in which the polishing efficiency is approximately maximized. 2. A measuring impedance is connected between the holder that holds the non-conductive workpiece and the grinding wheel support, and by detecting the potential difference between both ends of this measuring impedance, the workpiece is polished at the same time as the workpiece. a detection circuit for detecting an electromotive force generated in a holder, a means for rotating the workpiece relative to a grinding wheel surface so that the polishing direction of the workpiece is changed, and a means for detecting a polishing direction in which the electromotive force takes an extreme value. An automatic determination device for an optimum polishing direction, characterized in that the polishing direction in which the extreme value is determined to be the direction in which the polishing efficiency is approximately maximized. 3. A detection means for detecting a polishing surface linear force or a physical quantity corresponding to the tangential force when polishing a workpiece, a means for rotating the workpiece relative to the grinding wheel surface so that the polishing direction of the workpiece is changed, and the detection means and means for detecting a polishing direction in which a physical quantity detected by the means takes an extreme value, and determining the polishing direction in which the physical quantity takes an extreme value as a direction in which polishing efficiency is approximately maximized. Judgment device.