JP2003183726A - Control method and device for laser quenching - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adequately control the energy amount of a laser beam which irradiates a workpiece, according to amplitudes of the laser beam, to enable an appropriate hardening operation. <P>SOLUTION: In a laser quenching method of heating and hardening a predetermined width W1 in the workpiece 27, by irradiating with the swinging laser beam 29, while oscillating the laser beam in a predetermined amplitude W1, this method is characterized by controlling laser outputs in both ends of the amplitude of the laser beam, (e.g. points (1), (5), (6), and (10) in the Figure 4), so as to be lower than those in central parts of the amplitude, (e.g. points (3), (4), (7), and (8) in the Figure 4). Then, the method reduces an energy charge in both ends of the amplitude, in which otherwise energy charge density of the laser beam increases because a relative passing speed of the laser beam to the workpiece is lowered, consequently uniformizes the irradiation energy amount in every point of hardening cycles, and thereby enables the appropriate hardening operation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to laser hardening capable of hardening a workpiece with a predetermined width by rocking a laser beam in a direction intersecting a feed direction, and particularly, to a temperature of a hardening portion. The present invention relates to a laser quenching control method and a laser quenching apparatus capable of controlling the temperature constantly.

[0002]

2. Description of the Related Art Recently, there has been proposed a laser quenching method capable of quenching a work with a predetermined width by rocking the laser beam in a direction intersecting the feed direction.

[0003]

According to this method, the work can be quenched with an arbitrary width, but the moving speed of the laser light for the quenching with respect to the work always changes. Therefore, by simply irradiating the work with the laser light of a constant output, the irradiation energy per unit area at the quenching portion of the work becomes too high at the position where the relative speed of the laser light with respect to the work decreases, and the work melts. On the contrary, at the position where the relative speed of the laser light to the work increases, the irradiation energy per unit area becomes too low, and the temperature of the work does not rise to the predetermined quenching temperature, and quenching does not occur. Occurs.
Therefore, unless the irradiation energy amount of the laser light to the work is properly controlled according to the amplitude of the laser light, the appropriate quenching operation cannot be performed.

In view of the above circumstances, the present invention provides a laser quenching control method and a laser quenching method capable of appropriately controlling the irradiation energy amount of a laser beam with respect to a work according to the amplitude of the laser beam and performing a proper quenching operation. It is intended to provide a device.

[0005]

According to the invention of claim 1, the work (27) is rocked by irradiating the work (27) with a laser beam (29) vibrating at a predetermined amplitude (W1). In laser quenching in which the laser beam is heated to a predetermined quenching width (W1) to perform quenching, both ends of the amplitude of the laser beam (for example, time point (1) in FIG. 4,
The laser output at (5), (6), (10), etc. is represented by the central part of the amplitude (for example, time point (3) in FIG. 4,
(4), (7), (8), etc.) is controlled to be lower than the laser output.

According to a second aspect of the present invention, the laser is applied such that the quenching temperature of the workpiece when it is heated by being irradiated with the laser light is a predetermined quenching temperature at all quenching sites (27a) of the workpiece. It is characterized by adjusting the output.

According to a third aspect of the present invention, in the laser hardening control method according to the second aspect, the hardening temperature of the work is
The measurement is performed by capturing the reflected light (29a) of the laser light applied to the work.

According to a fourth aspect of the present invention, a laser output pattern (LOP1, LOP2) corresponding to the quenching operation is prepared, and a laser beam of laser light is generated based on the laser output pattern.
The laser output at both ends of the amplitude is controlled to be lower than the laser output at the center of the amplitude.

According to a fifth aspect of the present invention, by irradiating the work with a laser beam vibrating at a predetermined amplitude, a quenching cycle is formed by the trajectory of the laser beam, and the quenching cycle is executed for a plurality of cycles. In laser quenching for quenching the work, the temperature of the quenching site of the work is detected at a certain point in the quenching cycle (for example, point (1) of Cycle 0 of the quenching cycle in FIG. 4), and the temperature is detected. Based on the deviation (DF) between the cooling temperature and a predetermined quenching temperature, the quenching cycle (for example, as shown in FIG.
In the quenching cycle Cycle m), the laser output of the laser beam is adjusted so that the energy input density of the laser beam to the work in the quenching cycle is controlled to be uniform in the subsequent quenching cycle. Configured as a feature.

According to a sixth aspect of the present invention, there is provided a laser quenching control method according to the fifth aspect, wherein a laser output is adjusted in the subsequent quenching cycle (for example, a time point of Cycle m in the quenching cycle shown in FIG. 4 (1 ')) Is characterized in that it has the same phase as the time when the temperature of the quenching portion of the work is detected (for example, the time point (1) of Cycle 0 of the quenching cycle in FIG. 4) and the quenching cycle. .

The invention of claim 7 has a laser oscillator,
Light guide means (3, 9, 10, 12, 13, 16) for guiding the laser light (29) emitted from the laser oscillator is provided,
A laser quenching is performed by disposing a condenser lens (21) on the light guide means, condensing the laser light by the condenser lens, and irradiating the quenching site (27a) of the work (27) with quenching. In the device (1), beam oscillating means (16, 1) for oscillating the laser light with a predetermined amplitude (W1).
7, 25) for controlling the laser output of the laser light at both ends of the amplitude to be lower than the laser output at the central part of the amplitude. 37, 39, 40).

The invention of claim 8 has a laser oscillator,
A light guide means for guiding the laser light emitted from the laser oscillator is provided, a condenser lens is arranged in the light guide means, the laser light is condensed by the condenser lens, and the quenched portion of the work is irradiated with the light. In the laser hardening apparatus for hardening by means of the above, beam oscillating means for oscillating the laser light with a predetermined amplitude is provided, and temperature detecting means (22) for detecting the temperature of the hardened portion of the work is provided, and the temperature detecting means is provided. A target laser output (ROT) from a deviation (DF) between the detected temperature and a predetermined quenching temperature, based on the temperature of the quenching portion of the workpiece at a certain point in the quenching cycle detected by the means. In a quenching cycle after detecting the temperature of the quenching site based on the computed target laser output, a target laser output computing means (36) for computing Configured to provide a laser beam output control means (37,39,40) for adjusting the laser output of the laser beam.

[0013]

According to the invention of claim 1, both ends of the amplitude of the laser beam (for example, time points (1), (5), (6), and
The laser output at (10), etc. is measured by the central part of the amplitude (for example, time points (3), (4), (7), (8) in FIG. 4).
Control) so that the relative movement speed of the laser light with respect to the work is reduced and the energy input density of the laser light is increased. The irradiation energy amount can be made uniform throughout the quenching cycle. Thereby, an appropriate quenching operation can be performed.

According to a second aspect of the present invention, the laser output is adjusted so that the quenching temperature becomes a predetermined quenching temperature at all quenching portions (27b) of the work.
The amount of irradiation energy can be made uniform throughout the quenching cycle, and appropriate quenching operation can be performed.

According to a third aspect of the present invention, the quenching temperature of the work is set to the reflected light (29) of the laser light with which the work is irradiated.
By measuring by capturing a), the temperature of the quenching site can be accurately grasped, and an appropriate quenching operation can be performed.

According to the fourth aspect of the present invention, the laser output at the both ends of the amplitude of the laser light is controlled to be lower than the laser output at the central part of the amplitude based on the laser output pattern. Even without using such a feedback control, the temperature of the quenched portion can be easily controlled, and an appropriate quenching operation can be performed.

In a fifth aspect of the present invention, the temperature of the quenching portion of the work is detected at a certain point in the quenching cycle (for example, point (1) of Cycle 0 in the quenching cycle of FIG. 4), and the temperature is detected. Laser output of the laser beam in a quenching cycle (for example, Cycle m of the quenching cycle in FIG. 4) after the temperature of the quenching site is detected based on a deviation (DF) between the temperature and a predetermined quenching temperature. Therefore, the laser output can be properly adjusted even if a very fast quenching cycle is used, and a reliable quenching operation can be performed.

According to a sixth aspect of the present invention, the temperature of the quenching portion of the workpiece is set at the time when the laser output is adjusted in the subsequent quenching cycle (for example, the time point (1 ') of Cycle m in the quenching cycle in FIG. 4). Is detected to be in phase with the quenching cycle (for example, Cycle 0 of the quenching cycle in FIG. 4 (1)), the condition is similar in phase during the quenching cycle. With respect to the quenching part (27a), the laser output can be adjusted in a form that reflects the temperature detection in the past quenching cycle,
Highly reliable.

According to the invention of claim 7, it is possible to provide a laser hardening apparatus having the same effect as that of claim 1.

The invention of claim 8 can provide a laser hardening apparatus having the same effect as that of claim 5.

The numbers in parentheses are for convenience of showing the corresponding elements in the drawings, and the present description is not limited to the description in the drawings.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing a main part of a laser hardening apparatus to which the present invention is applied, FIG. 2 is a block diagram showing a main part of an NC apparatus, and FIG. 3 is a schematic view showing contents of a laser output value memory. FIG. 4 is a diagram showing a quenching trajectory of laser light, FIG.
6A is a schematic diagram showing the contents of each data block in the laser output value memory, FIG. 6A is a chart showing the locus (quenching cycle) of laser light, and FIG. 6B is a work of laser light corresponding to FIG. The speed chart for (c) is
(A) is a chart showing an example of a laser output pattern corresponding to (a), (d) is a chart showing another example of a laser output pattern corresponding to (a).

As shown in FIG. 1, the laser hardening apparatus 1 has a laser oscillator 2, and the laser oscillator 2 is provided with a saddle 5 through a duct 3 which is extendable and contractible.
Are connected. The saddle 5 is provided so as to be movable and driven in the Y-axis direction which is a horizontal direction via a guide means such as a column (not shown).
Further, the quenching head 7 has an upper reflecting cylinder 6 fixed to the saddle 5.

The upper reflecting tube 6 is provided with a first reflecting mirror 9, and the upper reflecting tube 6 has a duct 10 which is extendable and retractable in the Z-axis direction which is the vertical direction, and which is centered on the Z-axis. It is provided so as to be rotatable and positionable in the A-axis direction. A lower reflecting cylinder 11 is provided below the duct 10 in the figure, and a second reflecting mirror 12 is provided on the lower reflecting cylinder 11.

The lower reflecting cylinder 11 is provided with a duct 13 extending in the horizontal direction, and a side reflecting cylinder 15 is provided at the tip of the duct 13. Side reflector 15
Is provided with a third reflecting mirror 16, and the third reflecting mirror 1
6, a mirror swinging device 17 is provided with a third reflecting mirror 16 and a second reflecting mirror 16.
The laser beam path 19 between the reflecting mirror 12 and the third reflecting mirror 16 is swingably connected in the directions of arrows D and E about a swing axis VA perpendicular to the laser optical path 19. In the laser optical path 19 of the duct 13 between the third reflecting mirror 16 and the second reflecting mirror 12, the beam splitter 2
0, and a condenser lens 21 is provided below the side reflection tube 15 via a torch 24 attached to the bottom of the side reflection tube 15.

An infrared thermometer 22 is connected to the beam splitter 20 via a pickup 22a, and an NC device 23 is connected to the infrared thermometer 22.
The NC device 23 is connected to the above-mentioned mirror control device 25 connected to the mirror rocking device 17, and further to N
The C device 23 is connected to the head drive device 26 that drives the quenching head 7 and the laser oscillator 2.

As shown in FIG. 2, the NC unit 23 has a main control unit 30, and the main control unit 30 is connected to a mirror control unit 25 via a bus line 31 and a reflector position calculating unit. 32, a head drive controller 33 connected to the head drive device 26, a temperature deviation calculator 35 connected to the infrared thermometer 22, a target laser output calculator 36, a laser output value memory 37, a laser output synchronization controller 39, A laser oscillator control unit 40 connected to the laser oscillator 2 is connected.

Since the laser hardening apparatus 1 has the above-mentioned structure, when hardening the work 27, the work 27 is placed on the work table (not shown) below the torch 24 as shown in FIG. Installed and in that state, NC
A quenching operation is executed via the apparatus 23 based on a quenching program generated in advance corresponding to the workpiece 27 to be quenched.

First, the NC device 23 drives a table (not shown) to move the work 27 in the X-axis direction which is a horizontal direction orthogonal to the Y-axis, and at the same time, drives the head drive device 26 to drive the torch 24. Hardening head 7 including
The torch 24 is moved by driving the lower reflecting cylinder 11 together with the side reflecting cylinder 15 in the arrow A direction, and further rotating the side reflecting cylinder 15 in the arrow B direction. The workpiece 27 is opposed to the portion to be quenched.

Next, the NC device 23 commands the laser oscillator 2 to oscillate the laser light 29 at a predetermined output,
In response to this, the laser oscillator 2 emits a laser beam 29. The emitted laser light 29 enters the first reflecting mirror 9 from the duct 3, is reflected downward by the first reflecting mirror 9 in the figure, and is further reflected in the horizontal direction by the second reflecting mirror to be a beam. The light passes through the splitter 20 and enters the third reflecting mirror 16.

The laser light 29 incident on the third reflecting mirror is reflected by the third reflecting mirror downward in the drawing, that is, toward the work 27,
It is condensed by the condenser lens 21 and is irradiated onto the work 27. The work 27 is rapidly heated by being irradiated with the laser beam 29 and is quenched.

At this time, the work 27 is fed at a predetermined feed speed in the direction of arrow X by a drive mechanism (not shown) driven by the NC device 23, and the NC device 23 is based on the quenching width W1 designated by the quenching program. Drive the mirror swinging device 17 via the mirror control device 25,
The third reflecting mirror 16 is vibrated in the directions of arrows D and E. Then, the laser beam 29 incident on the third reflecting mirror 16 is swung with a width W1 in a direction (Y-axis direction) orthogonal to the X-axis direction of the arrow, which is the feed direction of the work 27, and the work 27 swings. Quenching is performed by heating the laser beam 29 to a predetermined temperature within the range of the width W1. The relative movement direction of the work 27 with respect to the torch 24 is the X-axis direction for simplification of description, but the control axis for positioning the torch 24 with respect to the work 27 is orthogonal to the X, Y, and Z axes. In addition to the control axis, the A axis, which is the rotation axis around the Z axis, and the B axis, which is the rotation axis around the Y axis, are used as the control axes, so that arbitrary three-dimensional positioning can be performed on the work 27. The hardening direction for the work 27 may be any direction in the three-dimensional space.

At this time, the quenching portion 2 for the work 27
In order to properly quench the 7a, the temperature of the quenching portion 27a needs to be accurately measured, but the temperature of the quenching portion 27a is measured by the infrared thermometer 22. The infrared ray measured by the infrared thermometer 22 is the irradiation portion 27 where the laser light 29 is currently radiating the laser light 29.
b is the infrared component of the reflected light 29a from b.
Reference numeral 9a denotes a condenser lens 2 from the irradiation portion 27b of the work 27.
First, the beam is incident on the beam splitter 20 via the third reflecting mirror 16, is reflected upward in the drawing by the beam splitter 20, and is incident on and captured by the pickup 22a of the infrared thermometer 22.

The infrared thermometer 22 has a pickup 22a.
Thus, it is possible to measure in real time the temperature of the quenching portion 27a where the laser beam 29 is currently applied and quenching is actually performed. That is, the beam splitter 20 that splits the reflected light 29 a to the pickup 22 a includes the laser oscillator 2 and the quenching portion 2 of the workpiece 27 for the laser light 29.
The laser beam 2 is arranged on the optical path between the third reflecting mirror 16 which is a beam swinging reflecting mirror for swinging with respect to 7a.
The condenser lens 2 downstream of the third reflecting mirror 16 on which 9 swings.
Since it is not arranged on the first side, the reflected light 29a from the work 27 always follows the path opposite to the incident path of the work 27 with respect to the quenching portion 27a and then passes through the condenser lens 21 to the third side.
It returns to the reflecting mirror 16 and enters the beam splitter 20.
As a result, even if the pickup 22a does not have a special tracking mechanism, the pickup 22a always reflects the reflected light 29 from the quenching portion 27a.
a can be captured, and the quenching portion 27a can be accurately
The temperature of can be measured. In addition, considering the attenuation of the reflected light 29a and the like, the position of the beam splitter 20 is
It is desirable to arrange it on the side of the third reflecting mirror 16 which is a beam swing reflecting mirror as much as possible.

Further, such a structure can be applied even when the torch 24 is moved and driven by the above-mentioned five-axis control to take various postures with respect to the work 27.
Whatever the posture of 4, the infrared thermometer 22
The temperature of the quenched portion 27a can be captured via the beam splitter 20.

When the infrared thermometer 22 measures the temperature of the quenching portion 27a, the NC device 23 determines whether or not the temperature has reached the quenching temperature set by the quenching program. Laser oscillator 2
Is adjusted so that the quenching portion 27a reaches the quenching temperature designated by the quenching program.

In the above-described embodiment, the beam splitter 20 allows the laser light from the laser oscillator 2 to pass therethrough, and reflects the reflected light 29 from the quenching portion 27a of the work 27.
The beam splitter 2 has a reflective shape.
The reflection type of 0 may be any reflection type.

As the temperature measuring means for the quenching portion 27a, any thermometer may be used in addition to the infrared thermometer 22 as long as the temperature of the quenching portion 27a can be measured from the wavelength of the reflected light 29a. Good.

The quenching operation of the work 27 with the laser light 29 is performed with a width W1 as shown in FIG. 4, and the locus TR of the laser light 29 on the work 27 is the third reflection of the laser light 29. The mirror 16 swings the workpiece 27 in the directions D and E perpendicular to the feeding direction of the workpiece 27.
Since the work 27 is fed in the X-axis direction at a predetermined feed rate, the amplitude becomes close to a sine wave of W1 / 2.

At this time, the relative velocity V of the trajectory TR of the laser beam 29 to the work (without considering the feed velocity in the X-axis direction).
Is shown in FIG. 6B, the laser beam 29
V becomes zero when the locus TR reaches the peak PK of the amplitude, and becomes maximum near the median value MP of the amplitude. Therefore, assuming that the laser beam 29 is applied to the work 27 while the output of the laser oscillator 2 remains constant, the laser per unit area irradiated to the work 27 is irradiated near the peak PK of the amplitude at which the relative speed V becomes slow. Median value of amplitude MP where light energy density increases and relative velocity V increases
In the vicinity, the energy density of the laser beam irradiated to the work 27 per unit area becomes low. In this state,
When the workpiece 27 is irradiated with the laser beam 29 to perform the quenching operation, variations in the energy input density cause quenching unevenness over the entire length of the trajectory TR.

Therefore, the NC device 23 includes the third reflecting mirror 16
The oscillation cycle in the directions of arrows D and E, that is, the locus TR of the laser light is divided by a predetermined sampling time SP as shown in FIG. In the example shown in FIG. 4, one cycle of the locus TR (the time required for one round trip of the third reflecting mirror 16, for example,
The locus of the laser beam on the workpiece in 10 ms, and this cycle is called the "hardening cycle" hereinafter.
It is divided into 0, and at each time (1) to (10), that is, every 1 ms, the temperature deviation calculation unit 35 is instructed to acquire the measured temperature TP of the quenching portion 27a of the work 27 measured by the infrared thermometer 22. .

Quenching with a laser beam is carried out by repeating this quenching cycle a plurality of times and by sending the workpiece 27 in a predetermined direction in which the quenching cycle proceeds (in the case of FIG. 4, the X-axis direction). .

The temperature deviation calculation unit 35 includes an infrared thermometer 22.
The deviation DF between the measured temperature TP of the quenching portion 27a input from the above and the designated quenching temperature TD designated in advance by the quenching program is calculated and output to the target laser output calculator 36. The target laser output calculation unit 36 calculates, based on the deviation DF, how much the output of the laser oscillator 2 should be set in order to bring the quenching portion 27a to the designated quenching temperature TD, and the target laser output is calculated. Calculate as output ROT. The target laser output calculation unit 36 shows the obtained target laser output ROT and the corresponding measured temperature TP in FIG. 5A together with the data ((1) to (10) in the drawing) indicating the temperature measurement time point. Thus, the data is stored in the corresponding address of the data block n0 of the laser output value memory 37.

That is, the measured temperature TP at time (1) and the target laser output ROT at that time are set to the address n01 at the measured temperature TP at time (2) and the target laser output ROT at that time.
To the address n02, the measured temperature TP at the time point (3) and the target laser output ROT at that time are stored at the address n03, and thereafter, similarly, the measured temperature TP at the time point (10) and the target laser output ROT at that time are stored. Is stored in the address n00 and the measured temperature TP of the quenching portion 27a for one cycle is stored.
And the target laser output ROT is stored. In the case of FIG. 5A, n0k (k: 1 to 9, 0) at each address,
The measured temperature TP is stored in the portion labeled "Temperature", the circled numbers on the right side of "Temperature" are the signs indicating the sampling points, and the target laser output ROT is further to the right.
For example, "600 W" is stored.

As a result, one of the swing cycles of the third reflecting mirror 16 indicated as "cycle 0" in FIG.
At the time points (1) to (10), the temperature of each quenching portion 27a and the laser output for bringing the quenching portion 27a to the predetermined quenching temperature designated by the quenching program are calculated as the target laser output ROT and stored. It

The NC device 23 sets the temperature of each quenching portion 27a for the "cycle 0" stored in this way and the target laser output ROT for bringing the quenching portion 27a to the predetermined quenching temperature designated by the quenching program. Based on the output of the laser oscillator 2, the target laser output ROT
By adjusting the value of the hardened part 27a to the predetermined hardening temperature specified by the hardening program, it is possible to perform an appropriate hardening operation on the work 27. A predetermined delay time is required to control the laser oscillator 2 to the output ROT, and further, the third reflecting mirror 16 is operated until the measured temperature TP at a certain quenching portion 27a and the target laser output ROT are calculated. Since it is driven to swing in the directions of arrows D and E,
Even if the output of the laser oscillator 2 is adjusted immediately after the target laser output ROT is calculated, the target laser output ROT
The laser beam 29 adjusted to the target laser output RO
The hardened portion 27a for which T has been calculated is not irradiated, but is displaced at a displaced position.

Since it is impossible to perform an appropriate quenching operation in this case, the main controller 30 instructs the laser output synchronization controller 39 to correspond to the measured temperature TP sampled at a certain point in time. The target laser output ROT is controlled so as to be executed at the same phase position, that is, at the same sampling time, in at least one cycle after the swing cycle of the third reflecting mirror 16, that is, the hardening cycle.

Specifically, the main control unit 30 causes the laser output synchronization control unit 39 to set "Cycle 0" in FIG.
The output control of the laser oscillator 2 based on the acquired measured temperature TP and the target laser output ROT corresponding to the measured temperature TP is a quenching cycle after m cycles (m: an integer of 1 or more), that is, "Cycle" in FIG. m ”, execute. At this time, each time point (1) in "Cycle 0"
The target laser output ROT obtained in (10) controls the laser oscillator 2 so that it is generated at each time point (1 ′) to (10 ′) in the corresponding “Cycle m”. At this time, the laser output synchronization control unit 39 can control the laser oscillator 2 in consideration of the delay time required for controlling the laser oscillator 2. Therefore, the laser oscillator can be accurately set at the quenching portion of the same phase after m cycles. The output of 2 is the target laser output ROT
The quenching portion 27a is accurately controlled to a temperature close to the quenching temperature designated by the quenching program, and an appropriate quenching operation is performed.

In the quenching cycle from Cycle 0 to Cycle m, the main controller 30 controls the subsequent Cycle.
1, Cycle 2, ... Cycle m-1 with 1 as above
At time points (1) to (10) divided into 10 ms, the measured temperature TP of the quenching portion 27a and the target laser output ROT at that time point are calculated and stored in the address of the corresponding data block of the laser output value memory 37. To do.

For example, the measured temperature TP and the target laser output ROT at each time point (1) to (10) in Cycle 1 following Cycle 0 are the data block n shown in FIG. 5 (b).
The measured temperature TP and the target laser output R at each time point (1) to (10) in Cycle m-1 immediately before Cycle m, which are stored in the address n1k (k: 1 to 9, 0) of 1 respectively.
The OT is stored in the address n (m-1) k (k: 1 to 9, 0) of the data block n (m-1) shown in FIG.

The storage mode of the data blocks in the laser output value memory 37 is schematically shown in FIG. 3, where data blocks n0 to n are stored.
The m data blocks up to (m-1) are connected and arranged in a ring shape, and the measured temperature TP and the target laser output ROT for the m data blocks are set.
When the storage of the data is completed, the laser output synchronization control unit 39 collectively reads the data of the next m + 1th data block, that is, the data block n0 in which the data of Cycle 0 is stored, and FIG. Store in an appropriate buffer memory as shown.

The laser output synchronization control unit 39 executes the cycle m at each time point (1 ') at the quenching cycle.
~ (10 '), the target laser output ROT at the corresponding time is read from the buffer memory shown in FIG.
At this point, the laser output is commanded to reach the target laser output ROT. In response to this, the laser oscillator controller 40
Controls the laser output of the laser oscillator 2 to be the target laser output ROT at that time.

That is, the laser output synchronization control unit 39 sets, for example, 600 W, which is the target laser output ROT obtained at the time point (1), to the time point (1) having the same phase as the time point (1) when the quenching cycle is Cycle m. A certain time before reaching 1 '),
For example, 5 ms before, the laser oscillator control unit 40 is instructed to set the output of the laser oscillator 2 to 600 W, and the laser oscillator control unit 40 immediately sets the output of the laser oscillator 2 to 60 W.
A command to turn it to 0 W is issued to the laser oscillator 2. As a result, at a time point (1 ′) after a predetermined time, the quenching portion 27a of the work 27 is irradiated with the laser light of 600 W, and the portion is brought to the predetermined quenching temperature designated by the quenching program as compared with the time point of Cycle 0. It is heated so that it approaches, and the quenching operation is performed.

In Cycle m, the time point (2 '),
(3 '), ... (9'), (10 '), a predetermined time before the laser light 29 arrives, the time point of Cycle 0 (2),
Since the target laser output ROT corresponding to (3), ... (9), (10) is read and the laser output ROT is controlled so as to become the target laser output ROT, the Cycle m is
At all of the sampling times, the hardening operation is performed by heating to a predetermined quenching temperature specified by the program in a manner closer to that at the time of Cycle 0.

When the quenching cycle of Cycle m is executed, as described above, Cycle m is newly added at each sampling time point (2 '), (3'), ... (9 '),
In (10 ′), the temperature measurement of the quenching portion 27a and the calculation of the target laser output ROT were performed, and the results were collectively read out when the quenching cycle of Cycle m of the laser output value memory 37 was executed. It is newly stored in the data block n0 as shown in FIG.

Thus, the quenching cycle to be executed thereafter is based on the measured temperature TP of the quenched portion 27a obtained in the quenching cycle before the previous m cycles and the laser output based on the target laser output ROT corresponding to the measured temperature TP. Is controlled, and the quenching cycle in the controlled state is also temperature-measured to obtain the corresponding target laser output R
Since the OT is calculated and reflected in the quenching cycle after the next m cycles, every time the quenching cycle is repeated, the quenching temperature of the quenching portion 27a in each quenching cycle is not limited to the quenching temperature specified in the quenching program. It is controlled by approaching.

As is clear from the target laser output ROT at each time point in each data block, FIG.
As shown in (a), at both ends of the amplitude of the laser light in the quenching cycle, as shown in (b) in the figure, the moving speed of the laser light 29 approaches zero, and the energy per unit area of the work 27 is reduced. Since the input density is high, as shown at the time points (1), (5), (6), and (10) of each data block in FIG. Energy is input and the work 27
Prevent the situation where the melted.

At the center of the amplitude of the laser light in the quenching cycle, as shown in FIG. 6 (b), the moving speed of the laser light 29 gradually increases and reaches the maximum near the position where the amplitude is 0. After that, it gradually decreases. Therefore, the work 2
The energy input density per unit area of 7 gradually decreases and becomes minimum at the position where the amplitude is 0, and then gradually increases.

Therefore, as shown in the time points (2), (3), (4), (7), (8) and (9) of each data block in FIG. 5, from the time points (1) and (6). , The laser output is increased as the point of amplitude 0 is approached, the amplitude 0 is peaked, and the laser output is adjusted so as to be decreased toward time points (5) and (10). 27a is uniformly energized over the entire amplitude of the laser light, that is, the quenching cycle, so that the quenching on the workpiece 27 is maintained at the quenching temperature specified in the quenching program during all the quenching cycles. Controlled.

In the above embodiment, the measured temperature T of the hardened portion 27a detected by the target laser output calculation unit 36 is detected.
Based on P, a target laser output ROT is calculated so as to reach a predetermined quenching temperature designated by a quenching program or the like, and based on the calculated target laser output ROT,
At least at the corresponding quenching portion 27a of the quenching cycle after one cycle, the laser output of the laser oscillator 2 was controlled to be the target laser output ROT, and the temperature of the quenching portion 27a was controlled to be the predetermined quenching temperature. Although the case has been described, in the present invention, in the laser hardening in which the work 27 is hardened by vibrating the laser light in the predetermined width W1, the laser output at both ends of the amplitude of the laser light is more than the laser output in the central part. As long as the control is performed so as to be low, the control may be performed by an open loop instead of the above feedback loop.

That is, as shown by the broken line in FIG. 2, the NC device 23 is provided with the output pattern memory 41 connected to the bus line 31, and the output pattern memory 41 is shown in FIG. 6 (c) or (d). As shown, the laser output pattern LOP1 or LOP2 in which the laser output LP is lowered and the laser output LP is raised in the central portion is stored in advance on the amplitude of the laser beam, that is, on both sides of the quenching cycle. A plurality of laser output patterns LOP1 and LOP2 are prepared according to the shape and material of the work, and are appropriately selected and used. When quenching the work 27, the laser output pattern LOP1 or LOP2 is output to the output pattern memory 41.
The laser output synchronization control unit 39 reads the laser output pattern LOP1 or LOP2 according to the swing position of the third reflecting mirror from the reflecting mirror position calculating unit 32, that is, the position of the quenching portion 27a in the quenching cycle. Based on this, the output of the laser light emitted from the laser oscillator 2 is adjusted. As a result, in the quenched portion 27a of the work 27,
Energy is uniformly applied over the amplitude of all the laser beams, that is, the quenching cycle, and the quenching of the workpiece 27 is performed at the quenching temperature specified by the quenching program.
It can be configured to control to be maintained throughout the quench cycle.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a main part of a laser hardening apparatus to which the present invention is applied.

FIG. 2 is a block diagram showing a main part of an NC device.

FIG. 3 is a schematic diagram showing the contents of a laser output value memory.

FIG. 4 is a view showing a quenching locus of laser light.

FIG. 5 is a schematic diagram showing the contents of each data block in the laser output value memory.

6A is a chart showing a locus (quenching cycle) of a laser beam, FIG. 6B is a chart showing a speed of a laser beam with respect to a work corresponding to FIG. 6A, and FIG.
(A) is a chart showing an example of a laser output pattern corresponding to (a), (d) is a chart showing another example of a laser output pattern corresponding to (a).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser hardening apparatus 2 ... Laser oscillators 3, 10, 13 ... Light guiding means (duct) 9 ... Light guiding means (first reflecting mirror) 12 ... Light guiding means (second reflecting mirror) 16 ... ... Light guiding means, beam oscillating means (third reflecting mirror) 17 ...... Beam oscillating means (mirror oscillating device) 21 ...... Condensing lens 22 ...... Temperature measuring means (infrared thermometer) 25 ...... Beam oscillating Moving means (mirror control device) 27 ... Work 27a ... Quenching site 29 ... Laser light 29a ... Reflected light 32 ... Laser output control means (reflecting mirror position calculation section) 35 ... Laser output control means (temperature deviation) Calculation unit) 36 ... Laser output control unit, target laser output calculation unit (target laser output calculation unit) 37 ... Laser output control unit, laser light output control unit (laser output value memory) 39 ... Laser output control unit, Laser light output control Stage (laser output synchronization control unit) 40 ...... laser output control means, the laser light output control means (the laser oscillator controller) LOP1, LOP2 ...... laser output pattern ROT ...... target laser output

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshihiko Inoue             Aichi Prefecture Oguchi-machi Oguchi-machi Large-scale small-scale character boarding number 1               Yamazaki Mazak Co., Ltd. Head Office Factory (72) Inventor Toshihiko Asari             Aichi Prefecture Oguchi-machi Oguchi-machi Large-scale small-scale character boarding number 1               Yamazaki Mazak Co., Ltd. Head Office Factory (72) Inventor Masaru Matsumura             Aichi Prefecture Oguchi-machi Oguchi-machi Large-scale small-scale character boarding number 1               Yamazaki Mazak Co., Ltd. Head Office Factory F-term (reference) 4E068 AH00 CA02 CB09 CC03 CD06                       CE03

Claims (8)

[Claims] 1. Laser quenching in which laser light is oscillated at a predetermined amplitude so that the work is oscillated so that the laser light oscillates to heat the workpiece with a predetermined quenching width, A laser hardening control method, wherein the laser output at both ends of the amplitude of light is controlled to be lower than the laser output at the center of the amplitude. 2. The laser output is adjusted so that the quenching temperature of the workpiece when it is heated by being irradiated with the laser light is a prescribed quenching temperature at all quenching points of the workpiece. The laser quenching control method described. 3. The method for controlling laser hardening according to claim 2, wherein the hardening temperature of the work is measured by capturing reflected light of laser light applied to the work. 4. A laser output pattern corresponding to the quenching operation is prepared, and based on the laser output pattern,
The laser output at both ends of the amplitude of the laser light,
2. The laser hardening control method according to claim 1, wherein the amplitude is controlled to be lower than the laser output at the central portion. 5. A quenching cycle is formed by irradiating a work with a laser beam vibrating at a predetermined amplitude to form a quenching cycle by the locus of the laser beam, and the quenching cycle is executed for a plurality of cycles to quench the workpiece. In laser quenching to be performed, at some point during the quenching cycle, the temperature of the quenching site of the workpiece is detected, and the temperature of the quenching site is detected based on the deviation between the detected temperature and a predetermined quenching temperature. After adjusting the laser output of the laser light in the quenching cycle, the energy input density of the laser light to the work in the quenching cycle is controlled to be uniform in the subsequent quenching cycle. A method for controlling laser hardening, which is characterized. 6. The laser quenching according to claim 5, wherein the time of adjusting the laser output in the subsequent quenching cycle is in phase with the time of detecting the temperature of the quenching portion of the work in the quenching cycle. Control method. 7. A laser oscillator is provided, light guide means for guiding the laser light emitted from the laser oscillator is provided, and a condenser lens is arranged in the light guide means, and the laser light is collected by the condenser lens. In the laser quenching device, which performs quenching by irradiating the quenching portion of the work with light, a beam oscillating means for oscillating the laser beam at a predetermined amplitude is provided, and the laser beam at both ends of the amplitude is provided. A laser hardening device, comprising a laser output control means for controlling the laser output to be lower than the laser output at the center of the amplitude. 8. A light guide means for guiding a laser beam emitted from the laser oscillator is provided, a condenser lens is arranged in the light guide means, and the laser light is collected by the condenser lens. A laser quenching device that performs quenching by irradiating a workpiece with a quenching portion, in a laser quenching device, a beam oscillating means for vibrating the laser light with a predetermined amplitude is provided, and a temperature for detecting the temperature of the quenching portion of the workpiece. Detecting means is provided, based on the temperature of the quenching portion of the work at a certain point in the quenching cycle detected by the temperature detecting means, a target that is a target from the deviation between the detected temperature and a predetermined quenching temperature. A target laser output calculating means for calculating a laser output is provided, and in a quenching cycle after detecting the temperature of the quenching site based on the calculated target laser output. , Which is configured by providing a laser light output control means for adjusting the laser output of the laser light, laser hardening device.