JPS606346A - Machining device for hard work by metal bonded diamond wheel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hard material processing device using a metal pound diamond grindstone.

For example, when cutting or grinding highly brittle work materials made of silicon nitride, other hard ceramics, glass, etc.
A diamond whetstone is used because it has the hardest abrasive grains and has excellent wear resistance. Moreover, metal pound grinding wheels are suitable because they have a greater ability to retain abrasive grains and have a longer lifespan than resinoid pound grinding wheels, vitrified bond grinding wheels, and the like.

However, when cutting and grinding hard work materials with such a cutting wheel, the metal pound strongly grips the diamond abrasive grains, but this does not cause moderate wear and tear as the abrasive cutting edge wears out. On the other hand, since the diamond abrasive grains wear quickly, the sharpness decreases rapidly, making it impossible to cut and grind easily.

In other words, if you continue grinding hard materials with a metal pound diamond grinding wheel, the diamond abrasive grains are less likely to break and the abrasive grains are strongly held by the metal pound. As a result, the peak of the variation in grinding resistance gradually increases as the grinding wheel wears, exceeding the limit of the torque of the grinding wheel drive motor, causing the grinding wheel speed to decrease and eventually to stop intermittently. reach. Therefore, if the metal pond is removed to make the abrasive grains protrude, and this is done continuously according to the wear of the abrasive grains, the required grinding performance can be maintained without increasing the grinding resistance.

The purpose of the present invention is to detect the coefficient of friction that acts between the grindstone and the material to be polished when removing metal pounds from such a diamond grindstone, and to apply electrolysis to keep the friction coefficient approximately constant. By controlling the speed and removing the metal pound, it is possible to efficiently process hard work materials with a grindstone that always has a sharp cutting edge.

In order to achieve this object, the hard material machining device of the present invention is a machining device equipped with a workpiece holding means for feeding the workpiece by holding the workpiece against a grinding wheel bonded with diamond abrasive grains by a metal pound. An electrolytic elution means for eluting the metal pound of the grinding wheel is provided between the grinding wheel and the electrode placed opposite thereto, and further, the grinding force acting on the workpiece is divided into a component force in the tangential direction of the outer periphery of the grinding wheel and a component of the grinding force acting on the workpiece. A detection means for detecting the force as two components of the vertical component force on the outer periphery of the grinding wheel, or a detection means for detecting the vertical component force on the outer periphery of the grinding wheel and the contact arc length between the grinding wheel and the workpiece in the above-mentioned cutting force is attached, and the above-mentioned The electrolytic elution means has a function for controlling the electrolytic speed so as to keep the friction coefficient obtained based on the output of the detection means or the cutting resistance per unit contact arc length between the grinding wheel and the workpiece substantially constant. It is constructed by providing an electrolysis rate control device.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the cutting device illustrated in FIG. 1, the cutting wheel IO is
It is constructed by attaching a grinding wheel part 13 in which diamond abrasive grains are bonded by a metal pound around a rotating disk 12, and is connected to a grinding wheel drive motor 6 of a drive system (not shown) and rotates at high speed. The hard work material 11 that is sent in the direction is cut with force. The workpiece holding means for holding the workpiece 11 and sending it to the grindstone includes a workpiece support device 14 equipped with a two-component force dynamometer, and the workpiece 11 is supported by this support device 14. It is sent towards the cutting wheel 10 in the state of being
115, and sent to an electrolysis rate control device 16 comprised of a microcomputer or the like. Further, the rotation speed of the cutting whetstone IO is detected by a tachometer 17 provided on the whetstone rotating shaft, and sent to the control device 1e.

On the other hand, in the two-component force dynamometer that constitutes a cutting resistance detection means between the grinding wheel and the workpiece, the tangential component Ft and the vertical component of the cutting force acting on the workpiece 11 at the time of cutting are determined. Two cutting components of the force Fn are measured and sent to the electrolysis rate control device 16. This causes the control device 16 to control the cutting wheel 1O and the work material 11.
The two-component force ratio Ft/ of the grinding resistance corresponding to the friction coefficient between
Fn is calculated, or the vertical component force Fn of the cutting force detected by the two-component force dynamometer and the length meter 1 are calculated.
5 and the shape of the workpiece given in advance.
After determining the contact arc length between o and the workpiece 11, the frictional force Fn in the normal direction per unit contact arc length corresponding to the cutting edge is calculated, and based on these values, as described later, The amount of metal pounds electrolytically removed by the cutting wheel 10 is controlled.

The removal of the metal pond by electrolysis is carried out by an electrolytic elution means provided on the cutting wheel lO. This electrolytic elution means includes an electrode 18 that covers a part of the cutting wheel 1o, and supplies an electrolytic solution between the electrode 18 and the cutting wheel 10 from a liquid supply pipe 18 in the electrode 18, and the electrode 18 and the cutting wheel 10 and are connected to the power supply 21 via the switch circuit 2°,
The structure is such that an electrolytic current is passed between the electrode 18 and the cutting wheel 10. The on/off control of the switch circuit 20 is performed by the control device 1G connected to it, and if Ft/Fn is below the desired value or Fn/ is above the desired value. If it turns around, the circuit is closed to allow the electrolytic current to flow; in the opposite case, the electrolytic current is interrupted. Therefore, the Ft/Fn or Fn/l is maintained at a substantially constant value.

FIG. 2 shows the timing at which the above-mentioned on/off control is performed in an actual cutting operation, and in the figure, REV indicates the number of revolutions (motor load) of the motor for rotating the grindstone.

Figures 3 to 6 show that in order to confirm the effect of electrolytic action in the cutting device of Figure 1, the electrode 1 was cut under the following conditions.
When a current is continuously passed between 8 and the cutting wheel 10 (
The results are shown in comparison for the case (with electrolysis) and the case where no current was applied (no electrolysis).

Whetstone used: diameter 125φ■, width approx. 1■ Whetstone rotation speed: approx. 308ORPM (peripheral speed 1200m/w)
in) Work material 5i3N4 (hot press) 25φam
Work material feeding speed 20mm/intestinal electrolysis voltage 0.
8.17V (Electrolysis current 3 Amax) Electrolyte solution (also used as processing fluid) 15$ NaC1 (approx. 1031 /win) 3rd
The figure shows Fn from the start to the end of cutting.

This shows how Ft changes. In the case of no electrolysis, it shows a rapid change in proportion to the increase in contact arc length, but in the case of electrolysis, Ft changes due to the removal of the metal pond. , Fn both decrease significantly, and the decrease in Fn is particularly remarkable, and moreover, these values hardly change.

In addition, Figure 4 shows how the maximum value of Ft changes as the number of cuts increases, and when electrolyzed, the maximum value of Ft either decreases slightly or remains almost unchanged. On the other hand, it can be seen that it increases proportionally when no electrolysis is performed. The maximum value of Fn also shows the same tendency as in Fig. 4.
However, if electrolysis is not used, F will increase as the number of cuts increases.
Both t and Fn increase, eventually exceeding the torque limit of the grindstone drive motor, and machining becomes impossible.

Figure 5 shows how Ft/Fn changes with machining time, and it shows a higher value when electrolyzed than when it is not used. It can be seen that it has become easier to bite into the material.

Figure 6 shows how Fn/l changes from the start to the end of cutting and as the number of cuts increases, and shows that the value without electrolysis is significantly larger than that with electrolysis. It can be seen that .

As is clear from the detailed description above, according to the present invention, when cutting hard materials using a cutting wheel in which diamond abrasive grains are bonded by a metal pound, the diamond abrasive grains are always kept at an appropriate protrusion amount. It can be carried out. Furthermore, although it is desirable that the sharpness of the whetstone improves due to the electrolysis of the metal pound, it is necessary to avoid unnecessary wear of the whetstone. It is extremely effective from an economic point of view to control electrolysis.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of the processing device of the present invention;
The figure is a diagram showing the timing of electrolysis in the processing equipment in relation to grinding resistance, etc., and Figures 3 to 6 are diagrams showing the effects of electrolysis in the processing equipment in comparison with the case without electrolysis. It is. 10.. Cutting wheel, ii.. Work material, 16.. Electrolysis speed control device, 18. Fighting electrode. Figure 8

Claims (1)

[Scope of Claims] 1. A processing device provided with a workpiece holding means for holding and feeding a workpiece to a grindstone to which diamond abrasive grains are bonded by a metal pound, the above-mentioned grindstone and an electrode disposed opposite thereto. Between 5 and 5, an electrolytic elution means is provided to elute the metal pound of the grinding wheel, and the grinding force acting on the workpiece is divided into two components: a tangential force on the outer periphery of the grinding wheel and a vertical component on the outer periphery of the grinding wheel. The method is characterized in that a detecting means for detecting is attached, and the electrolytic elution means is provided with an electrolytic speed control device for controlling the electrolytic speed so as to keep the friction coefficient obtained based on the direction of the detecting means substantially constant. A hard material processing device using a metal pound diamond grinding wheel. 2. In a processing device equipped with a workpiece holding means that holds and feeds a workpiece to a grindstone to which diamond abrasive grains are bonded by a metal pound, the grindstone is placed between the above-mentioned grindstone and an electrode disposed opposite thereto. an electrolytic elution means for eluting the metal bond, and a detection means for detecting the vertical component of the grinding wheel outer periphery and the contact arc length between the grinding wheel and the work material in the cutting force acting on the work material, The electrolytic elution means is equipped with an electrolytic speed control device that controls the electrolytic speed so as to keep the cutting resistance per unit contact arc length between the grinding wheel and the workpiece substantially constant based on the output of the detecting means. A hard material processing device using a metal pound diamond grindstone.