JPS639945B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a truing method for modifying the shape of metal bonded grindstones, particularly metal bond-CBN and diamond grindstones.

In general, when the rotating outer peripheral surface of a rotary grindstone becomes out of a perfect circle due to wear, rotational runout occurs, and due to this rotational runout, marks are left on the finished surface of the workpiece each time the grindstone rotates, and the workpiece is a mechanical component. It becomes unsuitable for use as a. As a method for modifying the shape of the above-mentioned rotating whetstone, there is a known method of using a vitrified WA grinding wheel with a low bonding degree.However, when the rotating whetstone is a metal bonded CBN or diamond grinding wheel, truing by the above method is difficult. This cannot be done easily due to the following reasons.

For this reason, it is possible to remove the metal bond in the above-mentioned rotating grindstone by electrolytic processing, but although this method is easier to process than the method using a WA grinding wheel, it is possible to uniformly electrolyze the entire surface of the rotating grindstone from the beginning. When processed, the shape with rotational run-out is maintained as it is and correction to a perfect circular state is not performed, and furthermore, it is extremely difficult to eliminate the rotational run-out by controlling the electrolytic machining conditions. Furthermore, when a rotary grindstone is processed by the above-mentioned electrolytic processing, there is a problem that the surface of the metal bond is covered with an anodic coating, thereby hindering the electrolytic processing.

The present invention provides a metal bond as described above.
The present invention aims to provide a method that can extremely easily perform efficient and highly accurate truing on CBN and diamond grinding wheels.

In order to achieve the above object, the truing method of the present invention detects the shape of a rotary whetstone using a shape sensor disposed on the surface of the whetstone in a state facing each other. The rotational runout signal is detected as a runout signal, and the rotational runout signal is compared with a preset slice level to detect a protruding part on the surface of the grinding wheel that is larger than the diameter corresponding to the slice level. When passing a position facing the electrolytic tool, an electrolytic current is passed between the rotary grinding wheel and the electrolytic tool to remove the metal bond on the protruding part of the grinding wheel by electrolytic processing, and the grinding wheel has a low bonding degree. By bringing the metal bond into contact with the rotating grindstone, the abrasive grains on the surface of the grindstone that are likely to fall off due to the electrolytic processing and the anodic coating generated on the surface of the metal bond are mechanically removed and detected by the shape sensor. When the output of the rotational run-out signal that is generated no longer exceeds the slice level, the set value of the slice level is lowered, and the electrolytic tool is brought closer to the rotary grindstone according to the progress of electrolytic machining detected by the rotational run-out signal. The present invention is characterized in that the above-described series of processes is repeated until rotational runout is no longer detected, thereby performing truing of the rotary grindstone.

The method of the present invention will be explained in more detail below with reference to the drawings.

FIG. 1 shows the configuration of an apparatus used for carrying out the present invention, in which 1 indicates a metal bond to be trued.
A CBN or diamond grindstone is rotatably supported by a rotating shaft 2 driven by a drive device (not shown).

The electrolytic tool 3 installed opposite to the outer peripheral surface of the rotary grindstone 1 is used to remove the metal bond of the rotary grindstone 1 by electrolytic machining, and there is a gap 4 between them having a distance t suitable for electrolytic machining. is provided, and electrolytic machining is performed between the electrolytic tool 3 and the rotary grindstone 1 by filling the gap 4 with electrolytic machining fluid from an electrolytic machining fluid supply pipe 5 provided above the gap 4. Ru. Therefore, the electrolytic tool 3 and the rotary grindstone 1 are connected via a DC power source 6 for electrolytic machining, a switch 7 that is opened and closed by an electric signal from the outside, and a rotating shaft 2 equipped with a conductive means such as a brush. ing.

A grindstone 8 installed on the opposite side of the above-mentioned rotary grindstone 1
The WA grindstone is used to mechanically remove abrasive grains that tend to fall off due to the electrolytic processing of the metal bond in the rotary grindstone 1, and the anodic coating formed on the surface of the metal bond by the electrolytic processing. It is rotatably supported by a drive shaft 9 which is rotatably driven by a drive device (not shown), and is movable toward and away from the rotary grindstone 1 by an arbitrary amount.

A shape sensor 11 disposed above the rotary whetstone 1 and facing the surface of the rotary whetstone 1
This is to detect the surface shape of the rotary grindstone 1.
Focusing on the fact that the gap between the surface of the rotary grindstone 1 and the shape sensor 11 changes in response to the unevenness of the surface of the rotary grindstone 1 as the wheel rotates, the surface shape is detected as a rotational run-out signal corresponding to the change. Further, the mark sensor 12 installed opposite to the grinding wheel 1 is for detecting the rotational position of the grinding wheel 1, and is designed to detect the rotational position from the mark displayed on the grinding wheel 1 etc. as an electrical rotational position signal. It is composed of

A signal processing circuit 14 to which each of the sensors 11 and 12 is connected compares the level of the rotational run-out signal with a preset slice level in synchronization with the rotational position signal, and calculates the diameter of the grindstone surface corresponding to the slice level. detecting a protruding portion larger than , and controlling the switch 7 to close the electrolytic power supply circuit at the protruding portion, that is, within a range where the output as a rotational shake signal is equal to or higher than the slice level; Furthermore, as the electrolytic machining of the rotary grindstone 1 progresses, a cutting signal is output to the WA grindstone 8, and when the rotational runout signal detected by the shape sensor 11 no longer exceeds the slice level. Then, the setting value of the slice level is lowered as appropriate, and a signal is output to bring the electrolytic tool closer to the rotary grindstone 1 by a certain distance, or the electrolytic tool is constantly adjusted to the gap 4 according to the progress of electrolytic machining. It outputs a signal to keep the value constant.

The truing of the rotary grindstone 1 using the above device is as follows:
The metal bond is removed by the electrolytic tool 3, and the CBN and diamond abrasive grains that tend to fall off are removed by the grindstone 8, and the anodic coating formed on the surface of the metal bond is also removed by the grindstone 8. However, these processes are not performed on the entire surface of the grindstone 1 from the beginning, but are performed while measuring the shape of the grindstone 1 in-process using the shape sensor 11 and mark sensor 12. The above processing is performed first on the protruding portions which are relatively less worn, and then repeated until the portions where the wear is most severe, that is, the portion of the grindstone 1 with the smallest radius.

Therefore, for example, when the shape of the rotary grindstone 1 to be processed is as shown in FIG. 2, the first circle 15 is
The outer first processed portion 18, the first circle 15 and the second
The second processed portion 19 sandwiched between the circle 16 and the third processed portion 20 sandwiched between the second circle 16 and the third circle 17 are sequentially removed, so that finally the third processed portion 19 is removed.
It will be processed into a perfect circle shape with a diameter D along the circle 17.

To explain this more specifically with reference to FIGS. 2 and 3, first, each rotation of the rotary grindstone 1, the surface shape is determined by the shape sensor 11 as shown in FIG.
is detected as a rotational runout signal shown by the solid line. The signal processing circuit 14 compares the rotational shake signal with a preset slice level A, and operates the switch 7 at the timing shown in FIG. An activation signal for activation is output, and at that timing, the switch 7 is turned on, and the electrolytic machining of the rotary grindstone 1 is repeated every rotation of the rotary grindstone 1. During this time, the grindstone 8 comes into contact with the rotary grindstone 1 and actively removes exposed CBN or diamond abrasive grains and the anodic coating on the surface of the metal bond. By repeating such machining, the first machining portion 18 of the rotary grindstone 1 is removed, and the rotational run-out signal becomes below the slice level A, as shown by the broken line in FIG. Upon completion, the slice levels in the signal processing circuit 14 are sequentially reset to B and C, thereby repeating the same processing as described above and sequentially removing the second and third processed portions 19 and 20 on the rotary grindstone 1. , the truing ends. Figure 3 c, d
indicates the timing at which the switch 7 becomes conductive in the second and third processing stages. When this timing signal reaches the ON state as shown in FIG. 3D, the truing ends.

Note that if the grain size of the grindstone 8 is appropriately selected in relation to the grain size of the rotary whetstone 1 to be processed, dressing of the rotary whetstone can be performed simultaneously with the above processing. It is also possible to use the end face of a bar-shaped grindstone instead of the grindstone 8.

As described above, according to the present invention, truing of a metal bonded rotary grindstone can be carried out extremely easily and efficiently.
It can be performed with high precision.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the apparatus used to carry out the present invention, Fig. 2 is an explanatory diagram of the machining process of the rotary grindstone, and Fig. 3
The figure is an explanatory diagram of the timing of energization for the processing. 1... Rotating grindstone, 3... Electrolytic tool, 6... Power source, 8... Grindstone, 11... Shape sensor, 14...
signal processing circuit.

Claims (1)

[Claims] 1. The shape of the rotating grindstone is detected as a rotational run-out signal corresponding to the change in mutual spacing that occurs as the rotation of the grinding wheel is detected by a shape sensor placed on the surface of the grinding wheel, and the rotational run-out signal is set in advance. A protruding part on the surface of the grinding wheel whose diameter is larger than the diameter corresponding to the slicing level is detected, and as the part passes through a position facing the electrolytic tool as the rotating grinding wheel rotates, the rotating The electrolytic processing is performed by passing an electrolytic current between the grinding wheel and the electrolytic tool, removing the metal bond on the protruding portion of the grinding wheel by electrolytic processing, and further bringing a grindstone with a low bonding degree into contact with the rotating grinding wheel. By mechanically removing the abrasive grains on the surface of the grinding wheel and the anodic coating formed on the surface of the metal bond, which are likely to fall off due to When it runs out, the set value of the slice level is lowered, and the electrolytic tool is brought closer to the rotary grindstone according to the progress of electrolytic machining detected by the rotational runout signal, and the above series of machining is repeated until the rotational runout is no longer detected. An electrolytic truing method for metal bonded grinding wheels, which is characterized in that truing of a rotary grinding wheel is performed repeatedly.