JPH0541396B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a dressing device for a grindstone of a grinding machine tool. More specifically, the present invention relates to an automatic dressing device for a diamond grindstone used for processing difficult-to-cut materials such as ceramics. [Prior Art] Dressing refers to the process of renewing and restoring sharpness when a whetstone becomes clogged or clogged, resulting in poor sharpness. Point dressers, which are usually made from a single diamond, Rotary dressers, crushing rollers, etc. are used depending on conditions such as the type of grinding wheel, grinding conditions, and type of workpiece. When processing difficult-to-cut materials such as ceramics, a diamond grindstone is used as the processing wheel because the workpiece is hard. However, since the workpiece is hard, the diamond grindstone wears quickly and requires frequent dressing. In order to dress a diamond whetstone, it would be better to have a whetstone harder than diamond, but since there is none, the dresser must be softer than this. Generally, GC whetstones and WA whetstones are used.
These wheels use a relatively soft bonding agent to improve the sharpness of the dressing. In other words, when a soft binder is used, the abrasive grains involved in grinding are renewed one after another, and the sharpness is maintained. Therefore,
These dresser grindstones suffer from several times to several tens of times more wear than diamond grindstones. It is necessary to correct the relative position between the diamond grindstone and the dresser grindstone by the amount of wear using the numerical control device. As a result, since the dressing starting point changes, there are problems in that it is difficult to automate the dressing work and that dressing takes a long time. In particular, it was difficult to automate the dressing work of a diamond grinding wheel by assembling it into the machining center that makes up the FMS. Even with automation, it was difficult because there are many shapes and sizes of diamond grinding wheels. Furthermore, as a result of dressing, the dimensions of the diamond grindstone for processing also change, which affects the processing dimensions. For this reason, measuring the dimensions of the workpiece and adjusting the amount of cut has to be done manually, making automation difficult. [Problem to be solved by the invention] In view of the above-mentioned problems, the following objects are achieved. SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic dressing device that automates the dressing work of diamond grindstones and automates the correction of the wear amount of each grindstone during dressing. Another object of the present invention is to provide an automatic dressing device that can be incorporated into a system such as FMS. [Means for solving the problem] The following measures are taken to solve the problem. This invention comprises: a) a main shaft 4 on which a grinding wheel 5 to be dressed is removably mounted; and b) provided to face the main shaft 4 and move relative to the main shaft 4 and clamp the pallet 8. A dressing device 7 installed in a machine tool 1, comprising a table 34 having pallet clamping means, c) a dresser grindstone 9 for dressing the grinding wheel 5 is provided on the pallet 8, and d the dresser Dresser drive means 20, 26, 22, 24, 25 for driving the grindstone 9 are provided on the pallet 8, and e the dresser drive means 20, 26, 22, 2
Power supply means 31, 32, 36 for supplying the power of 4, 25 from the outside of the pallet 8 are provided at the base of the machine tool 1 and the pallet 8, f) abrasion of the grinding wheel 5 during dressing or sensor 6 for detecting wear during machining;
10 is provided on at least one of the base of the machine tool 1 and the pallet 8. [Operation] A grinding wheel is chucked to the main shaft of a machine tool. A pallet equipped with a dressing device is called into the machine tool, clamped by a table, and the grinding wheel is dressed with a dressing wheel mounted on the pallet and driven to rotate. do. Furthermore, a sensor on the pallet detects wear of the grinding wheel during dressing or processing, and compensates for the amount of wear. [Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of a horizontal machining center 1 to which the present invention is applied. A column 3 is movable on the bed 2, and a main shaft 4 is rotatably provided on the column 3, and a diamond grindstone 5 is attached to the tip of the main shaft 4. The diamond grindstone 5 can be automatically replaced with another tool by an automatic tool changer (ATC) not shown. The spindle housing 4a that supports the spindle 4 is equipped with a detection ring 6 (described later) that detects contact between the diamond grindstone 5 and the dresser grindstone 9. The dressing device 7 has a structure in which a dressing grindstone 9, a measuring block 10, etc. are mounted on a pallet 8. This dressing device 7 is pooled in a pallet pool 12 like pallets 8 for processing other workpieces, and is transferred to a pallet changer 1.
Even 1 is exchanged. When it receives a call from the control device, it is clamped onto the table of the machining center 1 and becomes ready for dressing work. Dressing Device 7 FIG. 2 shows details of the dressing device 7.
FIG. 2a shows a plan view, and FIG. 2b shows a side view. A dressing device 7 is mounted on the pallet 8. Dressing device 7 mounted on pallet 8
A grindstone shaft 21 is rotatably provided in a housing 20 via a bearing. A dresser grindstone 9 is fixed to one end of the grindstone shaft 21, and a grindstone shaft pulley 23 is fixed to the opposite side. An air motor 26 is mounted parallel to the housing 20. A motor pulley 25 is fixed to the output shaft of the air motor 26. A belt 24 is stretched between the grindstone shaft pulley 23 and the motor pulley 25. The dresser grindstone 9 used here is basically a general GC grindstone, but in order to make it conductive,
It is divided into segments, and the segments are connected by metal layers 27. This metal layer 27 exists radially from the central hub portion to the outermost diameter of the grindstone. However, the grinding wheel part is connected and does not separate from the connection part between the grinding wheel part and the metal part. In addition, since the grinding wheel shaft 21 uses a normal rolling bearing, and the other parts are also made of metal, the metal layer 27 of the dresser grinding wheel 9 eventually passes through the grinding wheel shaft 21.
1. The housing 20, the pallet 8, the table of the machining center 1, the machine body such as the bed, etc.
electrically connected. Solenoid valve 31 and rotary valve 3 from air source 30 outside the machine
The guided air passes through the shaft 33 and the table 34, passes through the reference pad 35 on the top surface of the table, and enters the pallet 8 clamped thereon. A block 37 is attached to the pallet 8, and an air circuit is piped from the block 37 to the air motor 26. As mentioned above, the air that entered pallet 8 flows through pallet 8 and block 3.
It enters the air motor 26 through an air passage 36 provided at 7. FIG. 3 shows other necessary items, and in addition to the dressing device 7, a measuring block 10 is fixed to the upper surface of the pallet 8. The measuring block 10 has contacts 10a and 10b, which are also made of a conductor. When the diamond grindstone 5 is brought into contact with the contacts 10a and 10b, the wear of the dresser grindstone 9 can be checked using the NC position information of the feed of the spindle 4 at that time or the feed of the table that clamped the pallet 8. 9. Diamond whetstone 5
Measure by comparing with the dimensions of. In this embodiment, contact is simply detected, but a non-contact type air micrometer, electric micrometer, etc. may also be used. Furthermore, there is also a method of directly measuring the diameter or radius of the dresser grindstone 9 using a measuring device such as a differential transformer or a magnetic scale. A diamond grindstone 5 serving as a grinding wheel is attached to the main shaft 4 of the machining center 1 . The diamond grinding wheel 5 is roughly classified into resin bond and metal bond depending on the bonding material, but resin bond generally has no conductivity. However, it is also possible to make the bonding material conductive by adding metal powder to the bonding material. In the case of metal bonds, since they are inherently conductive, there is no problem in using them in the dressing device 7 of this embodiment. Hereinafter, the present invention is based on the premise that a conductive diamond grindstone 5 is used. The main spindle housing of the machining center 1 is equipped with a detection ring 6, and the tool attached to the main spindle 4 detects a conductor on a pallet 8, such as a metal part of a dresser grindstone 9 or a contact of a measuring block 10. 10a, 10b, etc., it can be detected and a skip signal can be given to a custom macro (a program that can be created by the user). In this embodiment, the detection ring 6 has two built-in cores, and when the tip of the diamond grindstone 5 comes into contact with the dresser grindstone 9 to form an RC closed circuit,
A circulating current flows through the excited core of the two cores, is captured by the other pickup core, and is sent as a touch signal to the control section (this is well known and not shown). Example of application to a vertical machining center (FIG. 4) FIG. 4 shows a case where the present invention is applied to a vertical machining center 40, in which FIG. 4a is a side view of the machine and FIG. 4b is a view from the top of a table 51. In the figure, there are two grinding wheel shafts 52, 5, a vertical axis and a horizontal axis.
A dressing device 50 having a
attached to the end of the This dressing device 50 includes two dresser grindstones 53 and 56. The grindstone shafts 52 and 55 of both dresser grindstones 53 and 56 are perpendicular to each other. The bottom surface of the diamond grindstone 44 is dressed with the side surface of the dresser grindstone 53 having the vertical grindstone shaft 52, that is, the horizontal surface 54. The diamond grinding wheel 4
Dress the circumferential surface of 4. The vertical machining center 40 usually has a table 5.
1, two dresser grindstones 53 and 56 are provided. In this embodiment, the dresser grindstones 53 and 56 are each of a type that is appropriately braked and rotates as the processing diamond grindstone 44 rotates. However, the dresser grindstone may be forcibly rotated as in the dressing device 7 shown in FIG. A measuring block 60 similar to the measuring block 10 is arranged adjacent to the dressing device 50. Dressing Operation and Measurement Operation We will consider two cases: dressing the end face portion of the diamond grinding wheel 5 and dressing the outer peripheral portion. Dressing of the end face is mainly required for cup-shaped grindstones.
Dressing work is carried out in the positional relationship shown in Fig. 3a-a. Further, the measurement following the dressing operation is carried out at the position B in Fig. 3a. Such position selection is performed using the table index and X, Y, and Z axis movement functions of the horizontal machining center. After selecting the position, the end face of the diamond whetstone 5 is pressed against the end face of the contactor 10b, and the wear of the diamond whetstone 5 is measured based on the contact position. All operations and corrections are performed using custom macros of the NC device. Call the custom macro using the following program. G65P X Z W H A Here, G65 is the macro call code, P is the end face dressing macro program number, X is the diameter of the diamond grinding wheel 5, Z is the dimension of the diamond grinding wheel in the Z direction, W is the radial length to be dressed, and H is the The tool offset number A is the type of bond, for example, 1: resin bond, 2: metal bond. Flow of End Dressing Operation (FIG. 5) The operation flow of end face dressing will be described in detail below with reference to a flowchart. FIG. 5 shows the operational flow of end face dressing. In FIG. 5, in a step, it is determined whether the diamond grinding wheel 5 is new by referring to a certain variable, and if it is new, there is no need for dressing, so the measurement operation is immediately started. At that time, the variables are automatically rewritten in the step, and a new grindstone will not be handled from next time onwards. Note that the variables used here can be set manually in advance, and by setting them on the new grindstone, only the measurement operation can be performed without performing the dressing operation. If it is determined in this step that the grindstone is not a new one, the process proceeds to the next step. Depending on the type of bond, a step or step is selected, and the number of dressings is optimally set, such as 10 times or 5 times, depending on the type of bond. The type of bond is determined based on the argument A of the macro call. The number of times set here is used in the dressing operation performed in the step. Next, in step, the pallet 8 is rotated 90 degrees in the B-axis direction (around the X-axis perpendicular to the plane of the pallet) according to the table index.
The angular positional relationship A between the dressing device 7 and the diamond grindstone 5 mounted on the main shaft 4 in FIG. 3a is obtained. Next, in a step, the device moves to the approach point shown in FIG. 6, that is, the starting point 0 of the dressing operation. In this embodiment, the dresser grindstone 9
The distance between the side surface and the circumferential surface of the diamond grinding wheel 5 is 10
mm, and the peripheral surface and tip surface were also set to 0.1 mm. This starting point is preferably located as close to the dresser grindstone 9 as possible in order to reduce the empty dressing time. The position of the dresser grinding wheel 9 is known in advance, and the outer diameter and width of the dresser grinding wheel 9 are stored separately in the tool offset memory, so the approach point is automatically calculated from these data. . Next, in a step, the main spindle rotation speed is determined, and in a step, the rotation of the main spindle 4 and the dresser grindstone 9 is turned on. Although the rotation of the dresser grindstone 9 is substantially constant, the rotation speed of the main shaft 4 is determined according to the outer diameter of the diamond grindstone 5 so as to have an optimum circumferential speed. Dressing operation is performed in steps. In Fig. 7, Fig. 7a shows that the diamond grinding wheel 5 is in the sixth position.
The operation starting from the position shown in the figure until it comes into contact with the dressing grindstone 9 is shown, and FIG. 7b shows the operation thereafter until the dressing is completed. In FIG. 7a, 0 represents the edge of the diamond grinding wheel 5 at the approach point, and the sequential movement of that point is represented by numbers assigned in that order. In other words, it moves at a fast rate from the approach point, then moves in the X direction, and returns (same as). Next, a cut is made in the Z-axis direction by a certain amount, for example, 10 μm, and the incision is moved from the position to the X-axis direction and returned to (the same position). As this process is repeated, it will come into contact with the dresser grindstone 9 several times. In the figure, it is assumed that contact occurred at point a on the way from to XI. Since both the diamond grindstone 5 and the dresser grindstone 9 are electrically conductive, the detection ring 6 in FIG.
Contact can be detected and obtained as a skip signal. When a skip signal is input, the operation of that block is interrupted, and from the point where the block returns to the starting point of the X-axis movement (in this example), the seventh
It becomes figure b. Here, in step, the rotation of the main shaft 4 and the dresser grindstone 9 is stopped, and in step, the table index angle is returned to its original position. As a result, the positional relationship of the diamond grindstone 5 with respect to the pallet 8 in FIG. 3 is as shown in (B). In the step, the position almost coincides with the center of the contact 10b of the end face measurement block 10 and is 10 mm away from the end face. Since the position of the contactor 10b is known in advance and the dimensions of the diamond grindstone 5 are given by the arguments X and Z of the custom macro calling program, the position is automatically calculated and moved to that position. End Face Measuring Operation In the end face measuring operation of the step, as shown in FIG. In FIG. 8b, it approaches the contact 10b in the Z-axis direction from the approach point at a fast feed rate, for example, about 800 mm/min, and makes contact at a point. The contact is detected by the detection ring 6 in FIG. 1 and is given as a skip signal. It jumps to the next block in response to a skip signal, and then moves forward at a slow rate, for example, about 50 mm/min, until it contacts the contact 10b. At this time, the actual Z dimension of the diamond grindstone 5 is calculated from the machine position at the point where the skip signal was obtained and the Z coordinate of the contactor 10b. In step, the tool correction is rewritten using the difference between the planned dimension, the actual dimension, and the actual Z dimension of the diamond grindstone 5 as the correction amount. Furthermore, the diameter of the dresser grindstone 9 is calculated from the machine position at the final stage of dressing and the measured grindstone size Z, and the corresponding tool correction memory is rewritten. Flow of Outer Periphery Dressing Next, dressing of the outer periphery is mainly required for flat grindstones, grindstones with shafts, etc., and the dressing operation is performed in the positional relationship shown in FIG. 3B (a). Further, following the dressing operation, the measurement operation is performed at the position B in FIG. 3B. Call the custom macro using the following program. G65P X Z W D A Here, G65 is the macro call code, P is the outer diameter dressing macro program number, X is the diameter of the diamond grinding wheel 5, and Z is the Z of the diamond grinding wheel 5.
In the directional dimension, W is the length of the outer diameter portion to be dressed, D is the tool offset number, and A is the type of bond, such as 1: resin bond, 2: metal bond, etc. FIG. 9 shows the operational flow of outer peripheral dressing. In the same figure, in the step, it is determined whether the diamond grindstone 5 is new by referring to a certain variable, and if it is new, there is no need for dressing, so the measurement operation is immediately started. At that time, the variables are automatically rewritten in the step, and a new grindstone will not be handled from next time onwards. Note that the variables used here can be manually set in advance, so by setting them on a new grindstone, only the measurement operation can be performed without performing the dressing operation. If in the step it is determined that the grindstone is not a new one, then in the next step the number of dressings is set to 10 or 5 depending on the type of bond. The type of bond is determined based on the argument A of the macro call. The number of times set here is used in the dressing operation performed in the step. Next, in step, confirm that the pallet 8 is at the original position on the B-axis (around the axis Y-axis perpendicular to the pallet surface), and if it is not at the original position, return it to the original position on the B-axis, as shown in Figure 3. The dressing device 7 and the diamond grindstone 5 attached to the main shaft 4 in b
The angular positional relationship with The next step is to move to the approach point shown in FIG. This position has substantially the same positional relationship as the end face dressing. The position of the dressing wheel 9 is predetermined.
Furthermore, since the outer diameter and width of the dresser grindstone 9 are stored separately in the offset memory of the tool, the approach point is automatically calculated from these data. Next, in step, the main spindle rotation speed is determined, and in step, the rotation of the main spindle 4 and the dresser grindstone 9 is turned on. Although the rotational speed of the dresser is approximately constant, the rotational speed of the main shaft 4 is determined according to the diameter of the diamond grindstone 5 so as to have an optimum circumferential speed. Dressing operation is performed in steps. In FIG. 11, FIG. 11a shows the operation of the diamond grinding wheel 5 from the position shown in FIG. 10 until it comes into contact with the dressing wheel, and FIG. 11b shows the operation thereafter until the dressing is completed. . In FIG. 11a, 0 represents the edge of the diamond grindstone 5 at the approach point, and the sequential movement of that point is represented by numbers assigned in that order.
In other words, it moves at a fast rate from the approach point, then moves in the Z direction, (same as)
Return to Next, make a cut in the X-axis direction by a certain amount, for example 10 μm, move from the position to the Z direction, and return to (same as). As this process is repeated, it will come into contact with the dresser grindstone 9 several times. In the figure, on the way from to XI
It is assumed that contact was made with Xa. Diamond whetstone 5
Since both the dresser grindstone 9 and the dresser grindstone 9 are electrically conductive, the detection ring 6 shown in FIG. When a skip signal is input, the operation of that block is interrupted and the block returns to the Z-axis movement starting point (X in this example), as shown in FIG. 11b.
Here, after completing a certain amount of cut in the X direction for the number of times n set in Step and Step, spark out is performed several times at the same cut position, and then the X-axis mechanical coordinates of that position are memorized. and then returns to the approach point (0 in Figure 11a). Note that during the series of operations in step, the first
The operation up to contact with the grinding wheel explained in Figure 1a is shown in Figure 11c.
It is also possible to carry out the method shown in . That is, it moves from the approach point 0 at a fast feed rate, and then moves in the X-axis direction at a slow rate. If the grindstone comes into contact with the grindstone on the way, a skip signal is input, so the movement in the X-axis direction is interrupted, and the state shown in FIG. 11b is from the position shown in FIG. The subsequent movements are as already described. Measurement of outer diameter Next, in step, the rotation of the spindle and dresser is stopped. In this step, the robot moves to the outer diameter measurement approach point (see FIG. 12). In this position, the end face of the diamond grinding wheel 5 is the measuring block 1.
It almost coincides with the center of the contact 10a of 0, and the outer diameter is Y
Located 10mm apart in the axial direction. Since the position of the contactor 10a is known in advance and the dimensions of the diamond grindstone 5 are given by the arguments X and Z of the macro calling program, the position is automatically calculated and moved to that position. In the step outer diameter measurement operation, the contact 10a
, contact 1 in the Y direction from the approach point
Approach 0a with a fast feed, for example about 800 mm/min, and make contact at a point. The first thing that came into contact with me was
It is detected by the detection ring 6 in the figure and given as a skip signal. The skip signal causes the contact 10a to jump to the next block, and then move slowly, for example at a rate of about 50 mm/min, to the next block.
move forward until it touches. At this time, the actual diameter X dimension of the diamond grindstone 5 is calculated from the machine position at the point where the skip signal was obtained and the Y coordinate of the contact 10a. In step, the tool correction is rewritten using the difference between the planned dimensions of the diamond grindstone 5 and the measured actual dimensions as the correction amount. Further, the diameter of the dresser grindstone 9 is calculated from the machine position at the final stage of dressing and the measured dimensions of the diamond grindstone 5, and the corresponding tool correction memory is rewritten. The above is for a horizontal machining center,
In the case of a vertical machining center, similar dressing work can be performed by slightly changing the dressing shape and processing software. Vertical machining centers usually do not have a table indexing function. In the embodiment shown in FIG. 3, there are two grindstones, one for end face dressing and the other for outer diameter dressing, so they can be used depending on the location to be dressed. That is, when dressing the end face of a horizontal machining center, table indexing is performed in the steps shown in FIG. 5, but in the case of a vertical machining center, dressing can be performed at the position of the dresser grindstone 9 shown in FIG. 3. Control Device for Dressing Apparatus FIG. 13 is a block diagram showing an example of the control device of the present invention. A machining program for machining a workpiece, a diamond grindstone (processing whetstone) diameter X, Z direction dimension Z, dressing length W, offset number H,
It is equipped with memory that stores data such as bond type A, data on the dresser grindstone, dressing programs, measurement programs, and the amount of wear on the diamond grindstone and the dresser grindstone. The dressing start position is detected by the detection ring 6, NC position information is taken out, the dressing start position is detected from this information, and dressing is started. Similarly, the measurement operation is such that the contacts 10a and 10b detect contact with the diamond grindstone, extract the position from the NC position information, calculate the amount of wear, and store the correction value. This value is used to correct the grindstone position during grinding. [Other Embodiments] The present invention is not limited to the above embodiments, and various design changes are possible within the scope of the basic technical idea of the present invention. An example of the change is shown below. In the embodiments described so far, the contact detection between the diamond grinding wheel 5 and the dresser grinding wheel 9 or the measuring block 10 is performed using the inductive detection type detection ring 6, but the method of contact detection is There is no need to limit it to this only. For example, it is also possible to insulate a part of the path from the main shaft to the housing, column, bed, and table, apply a potential difference before and after the path, and detect contact based on a change in the potential difference. Another method is to attach a strain gauge or IC pressure sensor to a measurement block or spindle head to detect the force at the time of contact. In the above embodiment, the measurement block 10 is provided on the pallet 8, but the measurement block 10
There is also a method of measuring the diamond grindstone 5 by fixing it to the column 3 or bed 2. There is a method of indirectly measuring the diamond whetstone by measuring the dresser whetstone 9 instead of measuring the diamond whetstone 5. This measurement can also be carried out by attaching a touch sensor to the spindle 4 and measuring the diameter of the dresser grindstone 9. [Effects of the Invention] As described above, the present invention has the following effects. a) Dressing of grindstones with various shapes, abrasive grains, and binders can be automated. b Since a dressing device is installed on the pallet,
Can be incorporated into systems such as FMS. c. The time required for dressing is shortened. d The grindstone dimensions after dressing are automatically corrected, making it easy to maintain machining accuracy.

[Brief explanation of the drawing]

The embodiment of FIG. 1 is a diagram showing the entire embodiment of the present invention, FIG. 2a is a plan view of the dressing device,
Figure b is a front view of the dressing device, Figure 3a is a front view showing the positions of dressing and measurement operations, Figure 3
FIG. 4b is a front view of the same, FIG. 4a is a diagram of another embodiment in which the dressing device of the present invention is applied to a vertical machining center, and FIG. 4b is a diagram showing the dressing device of FIG. 4a. FIG. 5 is a flowchart of the end dressing operation, FIG. 6 is a diagram showing the starting point of the end dressing operation, and FIG. 7a is a diagram of the operation path of the diamond grinding wheel until the dressing operation starts.
Fig. 7b is a movement path diagram of the dressing operation;
Figure c is a route diagram showing other operations, Figure 8a is a diagram showing the starting position of the end face measurement operation, Figure 8b is a route diagram showing the end face measurement operation, and Figure 9 is the operation flow for outer periphery dressing. 10 is a diagram showing the starting point of the outer peripheral surface dressing operation, FIG. 11 a is a route diagram until the outer peripheral surface dressing operation is started, FIG. 11 b is an operation route diagram of outer peripheral surface dressing, and FIG. 11 c 12A is a diagram showing another example of the outer circumference dressing operation, FIG. 12A is a diagram showing the starting point of outer circumference measurement, FIG. 12B is an operation path diagram for outer circumference measurement, and FIG. 13 is a control for controlling this embodiment. FIG. 3 is a control block diagram of the device. DESCRIPTION OF SYMBOLS 1...Machining center, 2...Bed, 3...Column, 4...Spindle, 5...Diamond grindstone, 6...Detection ring, 7...Dressing device, 8...Pallet,
9... Grindstone for dresser, 10... Measuring block, 1
1... Palette changer, 12... Palette pool.

Claims (1)

[Scope of Claims] 1 a. A main shaft 4 on which a grinding wheel 5 to be dressed is removably mounted; b. A dressing device 7 installed in a machine tool 1, comprising a table 34 having pallet clamping means for clamping the grinding wheel 5, and c) a dresser grindstone 9 for dressing the grinding wheel 5 is provided on the pallet 8; d dresser drive means 20, 26, 22, 24, 25 for driving this dresser grindstone 9 are provided on the pallet 8; e this dresser drive means 20, 26, 22, 2;
Power supply means 31, 32, 36 for supplying the power of 4, 25 from the outside of the pallet 8 are provided at the base of the machine tool 1 and the pallet 8, f) abrasion of the grinding wheel 5 during dressing or sensor 6 for detecting wear during machining;
10 is provided on at least one of the base of the machine tool 1 and the pallet 8.