JP2000153430A - Lathe using conical cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a conical cutter regardless of wearing thereof, so as to automatically perform work in high work accuracy. SOLUTION: The external peripheral surface of a vitrified grinding wheel 16 is automatically worked in a prescribed shape by operating a moving mechanism 22 in accordance with an NC data while rotatingly driving the vitrified grinding wheel 16 at a prescribed rotational speed so as to move conical cutters 12, 14 along a prescribed moving route. A cutting blade position is detected by making a cutting blade of the conical cutters 12, 14 abut to a limit switch arranged in a reference position, and the NC data is corrected based on a moving amount of the moving mechanism 22 at this detection time. In this way, deterioration of work accuracy caused by wearing of the conical cutters 12, 14 is prevented, and work is performed in high work accuracy regardless of wearing of the conical cutters 12, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lathe using a conical cutter, and more particularly, to a lathe which automatically performs processing by a conical cutter.

[0002]

2. Description of the Related Art Diamond wheels are widely used for finishing the outside diameter of vitrified grinding wheels. However, diamond wheels have a small cutting depth and poor machining efficiency. Uses a conical cutter. That is, (a) a headstock that rotationally drives a workpiece such as a grindstone around an axis, (b) a cutter holding table that rotatably holds a conical cutter around the axis, and (c) the headstock. Using a lathe having a moving mechanism for relatively moving the cutter holding table, the conical cutter is pressed against the outer peripheral surface of the workpiece to rotate together with the lathe, and both are relatively moved to form the outer peripheral surface into a predetermined shape. It is processed into. The conical cutter has a truncated conical cylindrical shape, and its large-diameter side edge is used as a cutting edge, and is pressed against the outer peripheral surface of the workpiece to crack the outer peripheral portion of the workpiece. Or brittle fracture is caused.

[0003]

However, such a lathe using the conical cutter has a problem that the operation requires skill because the operator manually operates the moving mechanism to perform the machining. That is, the conical cutter is generally made of metal such as shovel steel (tool steel) and wears faster than a diamond wheel. Therefore, when automated, sufficient machining accuracy cannot be obtained due to tool wear. It is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lathe which automatically performs machining with high machining accuracy using a conical cutter regardless of wear of the conical cutter. Is to do.

[0005]

Means for Solving the Problems In order to achieve the above object, a first invention comprises (a) a headstock for driving a workpiece to rotate about an axis, and (b) a conical cutter for rotating the workpiece around the axis. A cutter holder for rotatably holding, and (c) a moving mechanism for relatively moving the headstock and the cutter holder,
(d) a lathe for processing the outer peripheral surface into a predetermined shape by pressing and moving the conical cutter relative to the outer peripheral surface of the workpiece while rotating the conical cutter, (e) in advance according to the target shape By operating the moving mechanism in accordance with the set moving path data, the conical cutter moves the outer peripheral surface of the workpiece to its target shape, and (f) wear of the cutting blade of the conical cutter. Regardless of the above, there is provided a tool wear correction means for correcting the control of the movement mechanism by the movement control means so that the outer peripheral surface of the workpiece is machined into the target shape.

According to a second aspect of the present invention, in the lathe using the conical cutter according to the first aspect of the present invention, the tool wear correction means includes a cutting edge of the conical cutter positioned at a reference position having a fixed relation to the headstock. The headstock and the cutter when the cutting edge position detecting means detects that the cutting edge has been positioned at the reference position. Correction of control of the movement mechanism by the movement control means based on a relative position with respect to a holding table so that an outer peripheral surface of the workpiece is machined into the target shape regardless of wear of the cutting blade. It is characterized by being.

A third invention is a lathe using the conical cutter according to the first invention or the second invention, wherein a predetermined moving load is set when the headstock and the cutter holder are moved relative to each other by the moving mechanism. It is characterized by having speed control means for controlling the relative movement speed so as to fall within the range.

A fourth invention is a lathe using the conical cutter according to any one of the first to third inventions, wherein the workpiece is a vitrified grindstone, and a cutting blade of the conical cutter is pressed against the vitrified grindstone. It is characterized by having shaping means for controlling the moving mechanism so as to perform shaping.

A fifth invention provides a lathe using the conical cutter according to any one of the first invention to the fourth invention, wherein (a) vibration detecting means for detecting vibration of the conical cutter or the workpiece, and (b) The moving mechanism determines whether or not the conical cutter has contacted the workpiece based on the vibration detected by the vibration detecting means, and relatively moves at a high speed until the conical cutter contacts the workpiece. Characterized in that it has fast-forward means for controlling

According to a sixth aspect of the present invention, there is provided a lathe using the conical cutter according to the fifth aspect of the present invention, wherein the lathe includes damage detecting means for detecting damage of the conical cutter based on vibration detected by the vibration detecting means. .

[0011]

In such a lathe, the outer peripheral surface of the workpiece is automatically processed into the target shape by the movement control means, and the outer peripheral surface of the workpiece is irrespective of the wear of the cutting edge of the conical cutter. Since the control by the movement control means is corrected by the tool wear correction means so that the conical cutter is processed into the target shape, the processing is automatically performed with high processing accuracy regardless of the wear of the conical cutter.

In the second aspect of the invention, the tool wear correcting means includes a cutting edge position detecting means, and the headstock and the cutter holding when the cutting edge of the conical cutter is positioned at a predetermined reference position. Since the control of the movement mechanism by the movement control means is corrected based on the relative position with respect to the table, the correction is made according to the actual wear amount of the cutting blade, and based on wear data obtained through experiments and the like. Higher accuracy is obtained as compared with the case where the wear amount is estimated and corrected, and high processing accuracy is obtained.

In the third invention, the relative movement speed is controlled by the speed control means such that the movement load during the relative movement between the headstock and the cutter holder is within a predetermined range. High-efficiency machining is performed at a feed rate as fast as possible in accordance with a moving load within a range that satisfies predetermined machining conditions, such as avoiding breakage of a workpiece or a workpiece or satisfying required machining accuracy.

According to a fourth aspect of the invention, when the workpiece is a vitrified grindstone, the shaping means presses the cutting blade of the conical cutter against the vitrified grindstone to shape the work. In addition to preventing a reduction in machining accuracy, the apparatus is configured simply and inexpensively as compared with a case where a dedicated shaping tool is separately prepared.

According to a fifth aspect of the present invention, the vibration detecting means detects the vibration of the conical cutter or the workpiece,
Determine whether the conical cutter has contacted the workpiece,
Until the workpiece is contacted, the workpiece is relatively moved at high speed by the rapid traverse means, so that the relative movement time not involved in the processing (so-called approach time, air cut time, etc.) is reduced. Total machining time is reduced.

According to the sixth aspect of the present invention, the damage detecting means detects the damage of the conical cutter based on the vibration detected by the vibration detecting means. Minimized.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, a conical cutter is pressed against the outer peripheral surface of a workpiece, thereby causing cracks or brittle fracture on the outer peripheral portion of the workpiece, resulting in a high conical cutter. Since it is a process performed with efficiency, it is suitably used for the outer diameter finishing of vitrified grinding stones, especially for deformed finishing whose diameter dimension changes in the axial direction, but other brittle materials such as other grinding stones and porous ceramics Can also be applied to the processing of

Since the conical cutter is liable to wear, two types of conical cutters are provided, one for roughing, which has a large amount of processing, and one for finishing, which has a small amount of processing. It is desirable to perform the processing. In this case, it is preferable that the tool wear correction means is configured to separately correct the control of the moving mechanism by the movement control means in accordance with the wear of the two types of conical cutters. For example, the correction may be performed based only on the wear of the conical cutter for finishing. The shaping means is configured to shape at least the cutting edge of the conical cutter for finishing.

The moving mechanism for relatively moving the headstock and the cutter holding base is provided, for example, by moving the axis of the workpiece relative to a fixed headstock that rotationally drives the workpiece around a substantially horizontal axis. A biaxial moving table that translates the conical cutter in a substantially horizontal plane, and a rotary table that is disposed on the biaxial moving table and that changes the attitude (angle) of the conical cutter. However, the headstock may be moved by disposing the cutter holder at a fixed position.

The moving mechanism includes driving means such as a servomotor and a feed screw. The moving control means is controlled by a numerical control (NC) so that, for example, a conical cutter moves on a predetermined moving path. You. The speed control means is configured to detect, for example, a motor current (corresponding to a moving load) of a servomotor and to control a motor rotation speed (moving speed of the conical cutter) so that the motor current falls within a predetermined range. You.

In the second invention, the tool wear correcting means is configured to detect and correct the actual cutting edge position, that is, the amount of wear of the conical cutter by the cutting edge position detecting means. Depending on the size, material, allowance, etc.), data on the amount of wear of the conical cutter (wear data) may be obtained in advance through experiments or the like, and the amount of wear may be estimated and corrected based on the wear data. Various modes can be employed, such as by combining the periodic detection of the cutting edge position by the blade position detecting means (detection of the actual amount of wear) with the wear data, so that the correction can be made extremely finely and with high accuracy.

The correction may be performed step by step at a predetermined timing, such as at a predetermined processing time, at a predetermined processing length, at a predetermined processing volume, at a predetermined processing quantity, or the like. For example, the correction may be continuously performed in a series of processing steps, and may be appropriately set in consideration of required processing accuracy and the like according to the degree of wear of the conical cutter. In general, the detection of the cutting edge position according to the second aspect of the present invention is performed periodically at a predetermined timing, and it is appropriate to perform the correction stepwise in accordance with the amount of wear at that time. It is also possible to predict the amount of wear by obtaining the speed and make a continuous correction.

The cutting edge position detecting means of the second invention is constituted by, for example, a limit switch or a proximity switch which detects the cutting edge of the conical cutter in a contact or non-contact manner, and detects a contact between the conical cutter and the workpiece. The vibration detecting means to be detected can be used as the cutting edge position detecting means, in which case the contact position with the workpiece is the reference position. A contact member may be provided at the reference position, and the conical cutter may be moved by the moving mechanism so that the cutting blade contacts the contact member, and the contact may be detected based on a moving load at that time. The blade position detecting means can adopt various modes.

The cutting edge position detecting means detects that the cutting edge is located at the reference position, and sets the state as an initial position to N
If the target shape is processed by performing the processing according to the C data, etc., it is not particularly necessary to correct the NC data and the like due to the wear of the cutting edge, but in that case, the cutting edge is moved to the reference position. The movement itself corresponds to the correction of the control of the movement mechanism by the movement control means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The grinding wheel finishing lathe 10 shown in FIG. 1 is used for deforming the outer periphery of a vitrified grinding wheel 16 which is a workpiece by a pair of conical cutters 12 and 14, and a headstock 20 is placed on a substantially horizontal base 18. And a moving mechanism 22 are provided.
Numeral 6 is attached to the main shaft 24 of the headstock 20 and is driven to rotate about a substantially horizontal axis by a main shaft motor 26. The moving mechanism 22 includes an X-axis table 30 that is linearly reciprocated in a substantially horizontal X-axis direction (vertical direction in FIG. 1) via a feed screw (not shown) by an X-axis servomotor 28, and an X-axis table 30. And a Y-axis table 34 which is linearly reciprocated in a substantially horizontal Y-axis direction (left-right direction in FIG. 1) by a Y-axis servo motor 32 through a feed screw (not shown) and at right angles to the X-axis direction. The rotation servomotor 36 (see FIG.
), And a rotary table 38 that is rotated about a substantially vertical (vertical) rotation center S via a pinion or the like (not shown). The pair of conical cutters 12 and 14 The rotary table 38 is disposed in a substantially point-symmetrical attitude. Rotary table 3
Reference numeral 8 corresponds to a cutter holder.

As shown in FIG. 3, the conical cutters 12 and 14 have a truncated conical cylindrical shape, and large-diameter edges are used as the cutting blades 12a and 14a. The surface is pressed to generate cracks or brittle fracture in the outer peripheral portion to perform processing. The amount of cut varies depending on the degree of bonding of the vitrified grindstone 16, but is, for example, 2 mm.
(Approximately 10 times that of a diamond wheel), which enables high-efficiency machining. In the present embodiment, the cutting blade 12 is made of a shovel steel (a kind of tool steel) having a thickness of about 2 mm, and has a taper angle of about 105 ° and a cutting edge 12.
a and 14a have a diameter of about 95 mm and a diameter of about 5 mm.
It is used until it becomes about 0 mm. One conical cutter 12 is for finishing, and the cutting blade 12a is shaped substantially at right angles to the axis, whereas the conical cutter 14 is for roughing, and the cutting blade 14a is It is substantially perpendicular to the thickness direction.

As shown in FIG. 2, the conical cutter 12 is integrally and concentrically fixed to one end of a shaft 40, and is held by a housing 46 so as to be rotatable about an axis via a pair of bearings 42 and 44. The housing 46 is disposed on the turntable 38. A vibration sensor 48 such as a piezoelectric element is attached to the housing 46 as vibration detection means, and an air cylinder 50 is provided to apply a rotational resistance by pressing a friction material 52 such as rubber against the shaft 40. It has become. The housing 46 can be mounted so that the axis of the conical cutter 12 is vertically inclined with respect to the rotary table 38, and the inclination angle can be adjusted arbitrarily. The conical cutter 14 for roughing is also held rotatably about the axis similarly to FIG.
4 (see FIG. 4), the vibration is detected, and it is arranged on the turntable 38 at a predetermined inclination angle. The vertical inclination angles of these conical cutters 12 and 14 are as follows:
Depending on the size (outer diameter) of the vitrified grindstone 16 and the like, for example, about + 2 ° or about -2 ° is appropriate.

FIG. 4 is a block diagram for explaining a control system of the lathe 10 according to the present embodiment. The controller 60 is constituted by a microcomputer, a sequence control circuit, and the like. For example, according to the flowcharts shown in FIGS. Signal processing is performed so that the lathe 10 is operated. PC 6
2 stores in advance NC (numerical control) data including movement path data for moving the conical cutters 12 and 14 for processing the outer peripheral surface of the vitrified grindstone 16 into a target shape. In the present embodiment, in order to perform the outer peripheral finishing of a plurality of types of vitrified grindstones 16 having different outer diameters, thicknesses, and outer peripheral surface shapes, a plurality of types of NC data are stored, and the type of the grindstone to be subjected to the outer peripheral finishing is determined. When input by a user, the corresponding NC data is supplied to the controller 60.

The controller 60 includes the vibration sensor 4
Vibration signals representing the vibrations of the conical cutters 12 and 14 are supplied from the reference numerals 8 and 54, and the limit switch 64 disposed at a predetermined reference position on the base 18 is turned ON-O.
An FF signal is supplied. The limit switch 64 corresponds to a cutting edge position detecting means, and the moving mechanism 22 controls the cutting edge 12 of the conical cutters 12 and 14.
a, 14a are moved to the reference position, and the ON / OFF of the limit switch 64 is switched, so that the cutting blades 12a, 14a regardless of the wear of the cutting blades 12a, 14a.
The positional relationship between the position 14a (reference position), the headstock 20, and the vitrified grindstone 16 to be finished at the outer periphery is always kept constant. Therefore, the moving mechanism 2 at that time
If the NC data is corrected based on the amount of movement from the original position of No. 2, processing can be performed with high accuracy irrespective of wear of the cutting edges 12a and 14a.

The controller 60 controls the operation of the spindle motor 26, the X-axis servomotor 28, the Y-axis servomotor 32, and the rotation servomotor 36 according to the NC data, and switches the solenoid valves of the air circuit 66, etc. The operation of the air cylinder 50 is controlled. Encoder 28 provided in servo motors 28, 32, 36
e, 32e, rotational position signal from 36e can is supplied to the controller 60, the motor current I _M representing each torque or load from a current meter or the like for a servo motor 28, 32 is supplied to the controller 60.

In FIG. 5, after the worker attaches the vitrified grindstone 16 to be finished to the outer periphery to the main shaft 24, inputs the type and the like to the personal computer 62, and then turns on the start switch of the lathe 10, the first step is step S1. The NC data corresponding to the grindstone 16 is read from the personal computer 62. In this embodiment, as shown in FIG. 7A, a tapered first surface 16a and a stepped second surface 16b are provided on the outer peripheral surface of a disk-shaped vitrified grindstone 16 shown in FIG.
Will be described.

In step S2, the cutting mechanism 12a, 14a of the conical cutter 12, 14 is moved to the reference position by the moving mechanism 22, and the limit switch 64 is turned on and off.
Is changed, the NC data is corrected based on the movement amount of the moving mechanism 22 from the original position at that time so that the processing of the target shape can be performed regardless of the wear of the cutting blades 12a and 14a. The change in the amount of movement of the moving mechanism 22 when the conical cutters 12, 14 are moved to the reference position corresponds to the amount of wear of the cutting edges 12a, 14a, and the NC data is corrected according to the amount of wear. . Cutting blade 12a,
Since the wear amounts of the conical cutters 14a are different from each other, the cutting blades 12a and 14a of the conical cutters 12 and 14 are respectively brought into contact with the limit switch 64, and the respective moving amounts are obtained.
In step 14, the NC data of the portion to be processed is separately corrected.
The part that executes step S2 in the series of signal processing by the controller 60 functions as tool wear correction means. The inclination angles of the conical cutters 12 and 14 in the vertical direction are input in advance to the personal computer 62 and the like, and when calculating the amount of movement of the moving mechanism 22, a correction process is performed according to the inclination angles.

In step S3, the vitrified grindstone 16 is driven to rotate at a predetermined number of revolutions in accordance with the NC data, and the rotary table 38 is rotated to a predetermined position around the rotation center S, or while rotating, to perform finishing processing. The moving mechanism 22 is operated at a rapid feed until the conical cutter 12 contacts the vitrified grindstone 16. That is, the housing 4 of the conical cutter 12 for finishing
6. Read the vibration signal of the vibration sensor 48 provided in 6,
The conical cutter 12
Determines whether or not has contacted the vitrified grinding wheel 16,
They move (approach) by rapid traverse until they touch. The part that executes step S3 in the series of signal processing by the controller 60 corresponds to fast-forward means. If the stop is performed after the vibration sensor 48 detects the contact, the conical cutter 12 and the vitrified grindstone 16 are subjected to an impact due to an operation delay until the stop, and the feed speed is set so that the impact is not damaged. .

In step S4, the moving mechanism 22 is operated in accordance with the NC data, so that the conical cutter 1 is moved along the desired tapered shape as shown in FIG.
2 is moved to finish the tapered first surface 16a. At this time, the posture of the conical cutter 12 (the rotation angle of the rotary table 38) is set so that the axis of the conical cutter 12 intersects the first surface 16a at approximately 45 °, and the posture is cut by about 2 mm. While being reciprocated, the vibrated grindstone 16 is processed into a target shape while breaking the bond bridging. The part that executes step S4 in the series of signal processing by the controller 60 corresponds to movement control means. In addition, the said cutting amount is suitably set in the range of about 0.5 mm-2 mm, for example.

At the time of execution of step S4, signal processing shown in FIG. 6 is repeatedly executed at a predetermined cycle time by interrupt processing or the like. In step R1 of FIG. 6, the motor currents I _M of the X-axis servo motor 28 and the Y-axis servo motor 32 for moving the conical cutter 12 are read, and in step R2, the motor currents I _M are all lower limit values I _M. it is determined whether _min or more, it is determined whether more than the upper limit I _max in step R3.
Then, if I _min ≦ _IM ≦ I _max , step R5 is executed to maintain the rotation speeds of the servo motors 28 and 32 as they are, but if either one is I _max <I _M , step R4 executed, while decelerated by a predetermined rotational speed a rotational speed for instance predetermined its servo motor 28 or 32, in the case of either one But I _M <I _min executes step R6, the servo motor 28 or 32
Is increased by, for example, a predetermined constant number of revolutions. The motor current I _M corresponds to the load of the motor, that is, the moving resistance of the conical cutter 12, and the lower limit value I _min
And the upper limit I _max is required machining accuracy and machined surface shape, depth of cut, is appropriately set according to the processing conditions, such as failure strength of the vitrified grindstone 16 and Koni Calcutta 12, the motor current I _M is the lower limit of it, such as By controlling the motor speed so as to fall within the range of I _min and the upper limit I _max , high-efficiency machining is performed at a feed rate as high as possible according to the moving load. A part of the series of signal processing performed by the controller 60 for executing the steps R1 to R6 corresponds to a speed control unit. The upper limit I _max, as load on the Koni Calcutta 12 is 60kgf or less at the maximum, it is desirable to set in consideration of the lead angle of the feed screw, the feed speed so as to be less than 400 mm / min Is desirable.

In step R7, a vibration signal is read from the vibration sensor 48, and in step R8, it is determined from the amplitude and frequency of the vibration whether or not there is any abnormality including breakage (crack, etc.) of the conical cutter 12. If there is an abnormality, an abnormality is determined in step R9, and an abnormal lamp (not shown) is turned on or an emergency stop is performed. These steps R in the series of signal processing by the controller 60
The part that executes steps 7 to R9 corresponds to a damage detection unit.

Returning to FIG. 5, in step S5, by operating the moving mechanism 22 in accordance with the NC data, the corner 16c of the vitrified grindstone 16 on the opposite side to the first surface 16a as shown in FIG. In other words, while pressing the conical cutter 12 to a portion to be removed in a later process,
By switching the air circuit 66 and imparting rotational resistance to the conical cutter 12 by the air cylinder 50, the cutting blade 12a is ground by the grinding process using the vitrified grindstone 16.
Are shaped so as to be substantially perpendicular to the axis. The part that executes step S5 in the series of signal processing by the controller 60 corresponds to a shaping unit.

In step S6, by operating the moving mechanism 22 in accordance with the NC data, the conical cutter 14 is moved along the desired step shape as shown in FIG.
Is moved to roughly process the second surface 16b. The conical cutter 14 is reciprocated in a stepwise manner while being cut by about 2 mm, thereby processing the vitrified grindstone 16 into a target shape while breaking the bond bridging. In step S7, the finishing mechanism is operated by the conical cutter 12 for finishing by operating the moving mechanism 22 in accordance with the NC data. Of the series of signal processing by the controller 60, steps S6 and S
The part executing step 7 also functions as movement control means as in step S4.

Also at the time of execution of steps S6 and S7, signal processing similar to that of FIG. 6 is executed by interrupt processing or the like. That is, the motor currents I _M of the X-axis servo motor 28 and the Y-axis servo motor 32 are read, and the servo motors 28 and 32 are controlled so that the currents fall within a range between a predetermined lower limit I _min and an upper limit I _max . Control the speed,
The vibration signals are read from the vibration sensors 48 and 54, and the conical cutters 12 and 14 are read from the vibration amplitude and frequency.
It determines the presence or absence of abnormalities including damage (such as cracks), and makes an abnormal determination. Lower limit I _min and upper limit I
_{The max} is appropriately set depending on whether the conical cutter 12 or 14 is used, the required processing accuracy, the processed surface shape, the cutting depth, and the processing conditions such as the breaking strength of the vitrified grindstone 16 and the conical cutters 12 and 14. You.

According to such a lathe 10, the moving mechanism 2
By operating the spindle 2 and the main shaft 24 according to the NC data predetermined by the controller 60, the outer peripheral surface of the vitrified grindstone 16 is processed into a target shape. Compared to the case of processing by making it work, it can be processed easily without skill. In addition, a machining efficiency of about 10 times as compared with the case of automatic machining with a diamond wheel can be obtained, and a tool cost becomes about 1/100. That is, the number of processing per conical cutter is about 25 to 30.
In contrast, the number of diamond wheels processed is 20
Although it is 0 or more, the tool cost differs by about 1000 times or more, so the tool cost per machining number becomes about 1/100.

On the other hand, in this embodiment, the conical cutter 12
Since the wear correction is performed so that the target shape can be processed regardless of the wear of the 14 cutting blades 12a and 14a, the processing can be performed with high processing accuracy regardless of the wear of the conical cutters 12 and 14. In particular, in this embodiment, the amount of movement of the moving mechanism 22 is determined by bringing the cutting blades 12a and 14a into contact with the limit switch 64 disposed at the reference position to detect the cutting blade position, thereby correcting the NC data. So that
For example, higher accuracy can be obtained compared to a case where the amount of wear is estimated and corrected based on wear data obtained through experiments,
Higher processing accuracy can be obtained.

When the outer peripheral surface of the vitrified grindstone 16 is machined by the conical cutters 12 and 14, the motor currents I _M of the X-axis servo motor 28 and the Y-axis servo motor 32 are read, respectively, and these are set to predetermined lower limit values. I _min
Servo motor 2 to be within a range between the upper limit value I _max and
8, 32, the conical cutters 12, 14
, So that the moving load is controlled within a range that satisfies predetermined processing conditions such as avoiding damage to the conical cutters 12 and 14 and the vitrified grindstone 16 and satisfying required processing accuracy. High-efficiency machining is performed at a feed rate as fast as possible.

Further, a conical cutter 12 for finishing is provided.
Is the vitrified whetstone 1 after processing the first surface 16a.
6 is pressed against the corner 16c of the vitrified grindstone 1
6, the cutting edge 12a is shaped, so that the processing accuracy is prevented from lowering due to the change in the shape of the cutting edge, and the subsequent finishing of the second surface 16b is performed with high accuracy. The apparatus is simple and inexpensive as compared with a case where tools are separately prepared.

The first surface 1 by the conical cutter 12
When the conical cutter 12 is brought closer to the vitrified grindstone 16 prior to the processing of 6a, the vibration signal is read from the vibration sensor 48 and the conical cutter 12 contacts the vitrified grindstone 16 based on the presence or absence of vibration and the magnitude of the amplitude. Judge whether it is or not, and until it touches, conical cutter 1
2 is fast-forwarded, the approach time not involved in machining is reduced, and the total machining time including the approach time is shortened.

Also, when the outer peripheral surface of the vitrified grindstone 16 is processed by the conical cutters 12 and 14, the vibration sensor 4 attached to the housing 46 thereof is also used.
Since the vibration signals are read from the control units 8 and 54, the presence or absence of abnormalities including damage (cracks, etc.) of the conical cutters 12 and 14 is determined based on the amplitude and frequency of the vibrations. The occurrence of defective products due to breakage of the cal cutters 12, 14 is minimized.

The embodiments of the present invention have been described in detail with reference to the drawings. However, these embodiments are merely examples, and the present invention is based on the knowledge and knowledge of those skilled in the art. Can be implemented.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a lathe using a conical cutter according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a conical cutter of the lathe of FIG. 1 and a supporting device thereof.

FIG. 3 is a sectional view of a pair of conical cutters provided on the lathe of FIG. 1;

FIG. 4 is a block diagram illustrating a control system of the lathe in FIG. 1;

FIG. 5 is a flowchart illustrating the operation of the lathe of FIG. 1;

FIG. 6 is a flowchart illustrating signal processing performed simultaneously when steps S4, S6, and S7 of FIG. 5 are performed.

FIG. 7 is a diagram for explaining the progress of the processing of a vitrified grindstone whose outer periphery is finished by the lathe of FIG. 1;

[Explanation of symbols]

 10: Lathe 12, 14: Conical cutter 16: Vitrified grindstone (workpiece) 20: Headstock 22: Moving mechanism 38: Rotary table (Cutter holding table) 48, 54: Vibration sensor (Vibration detecting means) 60: Controller 64 : Limit switch (cutting edge position detecting means) Step S2: Tool wear correction means Step S3: Rapid feed means Steps S4, S6, S7: Movement control means Step S5: Shaping means Step R1 to R6: Speed control means Step R7 to R9: Damage detection means

Claims (6)

[Claims] 1. A headstock for rotating a workpiece around an axis, a cutter holding table for holding a conical cutter rotatably about the axis, and a relative movement between the headstock and the cutter holding table. A lathe for processing the outer peripheral surface into a predetermined shape by moving the conical cutter relative to the outer peripheral surface of the workpiece while pressing and rotating the conical cutter, the lathe having a moving mechanism, By operating the moving mechanism in accordance with the previously set moving path data, a moving control means for processing the outer peripheral surface of the workpiece to the target shape by the conical cutter; and Tool wear correction means for correcting the control of the movement mechanism by the movement control means so that the outer peripheral surface of the workpiece is machined into the target shape. Lathe with Koni Calcutta to butterflies. 2. A cutting edge position detecting means for detecting that the cutting edge of the conical cutter is relatively positioned at a reference position having a fixed relation to the headstock. Abrasion of the cutting blade based on the relative position between the headstock and the cutter holder when the cutting blade position detecting means detects that the cutting blade is located at the reference position. 2. The conical cutter according to claim 1, wherein the control of the movement mechanism by the movement control means is corrected so that an outer peripheral surface of the workpiece is machined into the target shape. Lathe using. 3. The apparatus according to claim 1, further comprising speed control means for controlling a relative moving speed such that a moving load when the headstock and the cutter holding base are relatively moved by the moving mechanism is within a predetermined range set in advance. A lathe using the conical cutter according to claim 1 or 2. 4. The work piece is a vitrified whetstone,
The conical cutter according to any one of claims 1 to 3, further comprising a shaping unit that controls the moving mechanism so as to press the cutting blade of the conical cutter against the vitrified grindstone to perform shaping. Lathe. 5. A vibration detecting means for detecting vibration of the conical cutter or the workpiece, and determining whether the conical cutter has contacted the workpiece based on the vibration detected by the vibration detecting means. The conical cutter according to any one of claims 1 to 4, wherein the conical cutter has a fast-forward means for controlling the moving mechanism so as to make a relative movement at a high speed until the workpiece is brought into contact with the workpiece. Lathe used. 6. A lathe using a conical cutter according to claim 5, further comprising a damage detecting means for detecting breakage of said conical cutter based on vibration detected by said vibration detecting means.