JPS6246310B2 - - Google Patents

Description

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

For example, when cutting or grinding a highly brittle work material made of silicon nitride, other hard ceramics, glass, etc., a diamond grindstone, which has the hardest abrasive grains and has excellent wear resistance, is used. Moreover,
Metal bonded whetstones are more suitable than resinoid bonded whetstones, vitrified bonded whetstones, etc., as they have a greater ability to retain abrasive grains and have a longer lifespan.

However, when cutting and grinding hard work materials with such a cutting wheel, the metal bond strongly grips the diamond abrasive grains, but this causes moderate wear and tear as the abrasive cutting edge wears. On the other hand, the diamond abrasive grains wear quickly, so the sharpness decreases rapidly and cutting and grinding cannot be performed easily.

In other words, if you continue grinding hard materials with a metal bond diamond grinding wheel, the diamond abrasive grains are less likely to break and the abrasive grains are strongly held by the metal bond. As a result, the peak of fluctuation in grinding resistance gradually increases as the grinding wheel wears, exceeding the torque limit of the grinding wheel drive motor, resulting in a decrease in the speed of the grinding wheel, and eventually stopping intermittently. . Therefore, if the metal bond is removed to make the abrasive grains protrude, and this is done continuously as the abrasive grains wear out, the grinding resistance will not increase.
This means that the required grinding performance can be maintained.

The purpose of the present invention is to detect the friction coefficient that acts between the grinding wheel and the workpiece when removing the metal bond of such a diamond grinding wheel, and to adjust the electrolysis rate to keep the friction coefficient approximately constant. By controlling and removing metal bonds, it is possible to efficiently process hard work materials with a grindstone that always has a sharp edge.

In order to achieve this object, the hard material processing device of the present invention is a processing device equipped with a workpiece holding means that holds and feeds the workpiece to a grindstone to which diamond abrasive grains are bonded by metal bond. ,
An electrolytic elution means is provided between the grinding wheel and the electrode placed opposite to it to elute the metal bond of the grinding wheel, and the grinding force acting on the workpiece is divided into a tangential component of the grinding wheel's outer periphery and a vertical component of the grinding wheel's outer periphery. A detection means for detecting a two-component force of the directional force, or a detection means for detecting a vertical component force on the outer periphery of the grinding wheel and a contact arc length between the grinding wheel and the workpiece in the cutting force, is attached to the electrolytic elution means. , an electrolysis speed control device for controlling the electrolysis speed so as to keep the friction coefficient obtained based on the output of this 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

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

In the cutting device illustrated in FIG. 1, a cutting whetstone 10 includes a whetstone portion 13 in which diamond abrasive grains are bonded around a rotating disk 12 by a metal bond.
The hard work material 11 sent in the direction of the arrow x is cut by being connected to a grindstone drive motor of a drive system (not shown) and rotating at high speed. 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 4. It is sent toward the cutting wheel 10 in a state where it is fed, the amount of the feed is measured by a length meter 15, and sent to an electrolysis rate control device 16 constituted by a microcomputer or the like. Further, the rotational speed of the cutting whetstone 10 is detected by a tachometer 17 provided on the whetstone rotating shaft, and is sent to the control device 16.

On the other hand, in the above-mentioned two-component force dynamometer that constitutes a cutting resistance detection means between the grinding wheel and the workpiece, the tangential direction component Ft and the vertical direction 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 these are applied to the electrolysis rate control device 16.
sent to. As a result, the control device 16 calculates the two-component force ratio Ft/Fn of the grinding resistance corresponding to the friction coefficient between the cutting wheel 10 and the workpiece 11, or the two-component force dynamometer Vertical component of the detected cutting force Fn and the length total 1
After determining the contact arc length l between the grinding wheel 10 and the workpiece 11 using the output of step 5 and the shape of the workpiece given in advance, the normal direction per unit contact arc length corresponding to the cutting edge is calculated. The frictional force Fn/l is calculated, and based on these values, the amount of electrolytic removal of the metal bond in the cutting wheel 10 is controlled as described later.

The removal of the metal bond by electrolysis is performed by an electrolytic elution means provided on the cutting wheel 10. This electrolytic elution means includes an electrode 18 covering a part of the cutting whetstone 10, and supplies an electrolytic solution between the electrode 18 and the cutting whetstone 10 from a liquid supply pipe 19 in the electrode 18. is connected to a power source 21 via a switch circuit 20, and an electrolytic current is caused to flow between the electrode 18 and the cutting wheel 10. The above switch circuit 20
On/off control is performed by the control device 16 connected to it, and if the Ft/Fn falls below the desired value or Fn/l exceeds the desired value, the electrolytic The circuit is closed to allow current to flow, and in the opposite case the electrolytic current is interrupted.
Therefore, Ft/Fn or Fn/l is maintained at a substantially constant value.

Figure 2 shows the timing at which the above-mentioned on/off control is performed for actual cutting work.
In the figure, REV indicates the rotation speed (motor load) of the motor for rotating the grindstone.

3 to 6 show that a current was continuously passed between the electrode 18 and the cutting wheel 10 under the following conditions in order to confirm the effect of electrolytic action in the cutting device shown in FIG. 1. For each case (with electrolysis) and when no current is applied (no electrolysis),
This is a comparison of the results.

Grinding wheel used: Diameter 125φmm, Width approx. 1mm Grinding wheel rotation speed Approx. 3060RPM (peripheral speed 1200m/min) Work material Si ₃ N ₄ (hot press) 25φmm Work material feeding speed 20mm/min Electrolytic voltage 0, 8, 17V (electrolytic current 3Amax) ) Electrolyte (also used as machining fluid) 15% NaCl (approximately 10/min) Figure 3 shows the
This shows how Fn and Ft change.
In the case of no electrolysis, there is a rapid change in proportion to the increase in the contact arc length, but in the case of electrolysis, both Ft and Fn decrease significantly due to the removal of the metal bond, and the decrease in Fn is particularly pronounced. noticeable, and their 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. If electrolysis is not used, Ft and Fn will decrease as the number of cuts increases.
increases together, and eventually exceeds the torque limit of the grindstone drive motor, making it impossible to process.

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

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 a hard material using a cutting wheel in which diamond abrasive grains are bonded by metal bond, the diamond abrasive grains can always be kept at an appropriate protrusion amount. Cutting can be done. Furthermore, although it is desirable that the sharpness of the whetstone improves through electrolysis of the metal bond, it is necessary to avoid unnecessary wear of the whetstone. Controlling electrolysis so as to maintain the temperature is extremely effective from an economic point of view.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the processing device of the present invention, Fig. 2 is a diagram showing the timing of electrolysis in the processing device in relation to grinding resistance, etc., and Figs. 3 to 6 are the above-mentioned diagrams. FIG. 2 is a diagram showing the effect of electrolysis in a processing device in comparison with a case where no electrolysis is performed. 10... Cutting wheel, 11... Work material, 16...
Electrolysis rate control device, 18...electrode.

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 bond, the above-mentioned grindstone and an electrode disposed opposite thereto. An electrolytic elution means is provided between the grinding wheel and the metal bond to elute the metal bond 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 force 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 output of the detecting means substantially constant. A hard material processing device using a metal bond diamond grindstone. 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 bond, there is a An electrolytic elution means is provided to elute the metal bond of the grinding wheel, and a detection means is further provided to detect the vertical component of the outer periphery of the grinding wheel in the cutting force acting on the work material and the contact arc length between the grinding wheel and the work material. , an electrolytic speed control device is installed in the electrolytic elution means to control 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 bond diamond grindstone, which is characterized by being equipped with a metal bond diamond grinding wheel.