JPH0253485B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a laser surface treatment device that uses a laser beam to improve the surface characteristics of a workpiece.
More specifically, the present invention relates to an apparatus for hardening the surface of a workpiece.

(Prior technology) Laser hardening technology, which irradiates the workpiece surface with a laser beam to rapidly heat the workpiece surface and form a hardened layer by self-cooling the workpiece, has the following advantages: It is known that it has characteristics such as extremely small thermal deformation of the shape when inserted, and no need for oil, water, etc. for cooling.

By the way, conventionally, when hardening the surface of a workpiece, defocusing or the like is performed so that the spot diameter becomes a predetermined diameter. Further, the cross-sectional shape of the laser beam has generally been circular.

(Problems to be Solved by the Invention) When hardening the surface of a workpiece by defocusing, the spot diameter of the laser beam on the surface of the workpiece must always be constant. Therefore, if the workpiece surface is flat, there is no major problem, but if the workpiece surface has undulations or a stepped hole is drilled in the workpiece, hardening of the step inside the hole may cause problems. In this case, there was a problem in that it was difficult to uniformly harden the steel.

In addition, since the cross-sectional shape of the laser beam is circular, when hardening the outer circumferential surface of a cylinder, for example, the hardening start position and end position will be in a manner where the arcs touch, so the hardening start position and end position will be in contact with each other. The boundary becomes constricted and the quenched width becomes narrow. Therefore, by overlapping the quenching start position and end position so that the quenching width is approximately constant, the quenching start position will be heated twice, at the start and end of quenching, resulting in a qualitatively uniform There was a problem in that it was difficult to harden.

The present invention has been made in view of the above-mentioned problems.

[Structure of the invention] (Means for solving the problems) In order to solve the conventional problems as described above,
The present invention includes a work table that supports a workpiece to be surface-treated, a laser oscillator that oscillates a laser beam to be irradiated to the workpiece, and a cross-sectional shape of the laser beam oscillated from the laser oscillator that is parallel to one part of the cross-section. a beam deforming means for deforming the laser beam into a cross-sectional shape having a shaped portion and substantially uniformizing the intensity distribution of the beam within the cross-sectional shape; a collimating means for collimating the laser beam that has passed through the beam deforming means; and a processing head that irradiates the surface of the workpiece with a laser beam.

(Function) With the above configuration, the laser beam emitted from the laser oscillator is collimated and irradiated onto the workpiece, so even if the distance between the processing head and the workpiece changes, the laser beam emitted from the laser oscillator will not reach the workpiece. The energy density of the irradiated part is constant. Therefore, even if the surface of the workpiece has undulations, steps, etc., uniform hardening can be performed.

As mentioned above, when irradiating a workpiece with a laser beam, the cross-sectional shape of the laser beam is formed to have a parallel portion in one part, and the intensity distribution of the beam within the cross-sectional shape is made almost uniform. In addition to being able to perform hardening over a wide range, the entire hardening width can be made uniform without overlapping the hardening start and end positions.

(Example) Referring to FIGS. 1 and 2, a laser surface treatment apparatus 1 according to the present example includes a work table 3 that supports a work W to be surface-treated, and a side surface of the work table 3. At the position is a laser oscillator 5 that oscillates a laser beam LB to irradiate the workpiece W.
It is equipped with Since this laser oscillator 5 may be of a general type, a detailed explanation thereof will be omitted.

The work table 3 is mounted in the X-axis direction (Fig. 1,
It comprises a movable table 7 that is movable in the left-right direction in FIG. 2 and a rotary table 9 that is supported by the movable table 7 and can freely rotate horizontally.
The workpiece W is horizontally mounted on the rotary table 9 via a suitable fixture, such as a magnetic chuck (not shown). In this example,
The workpiece W is exemplified as a disk having holes H at an appropriate number of locations.

In the above configuration, by automatically performing the movement and positioning of the movable table 7 and the rotation and rotational positioning of the rotary table 9, a desired hole H of the workpiece W can be positioned at a predetermined position.

As can be understood from FIGS. 1 and 2, a column 11 is provided upright at a side position of the movement area of the work table 3. A guide member 12 extending in the Y-axis direction across is supported in a cantilevered manner. A processing head 13 that irradiates a desired position of the work W with a laser beam LB from the laser oscillator 5 is supported on the guide member 12 so as to be movable in the Y-axis direction. This processing head 13
is a servo motor 15 attached to the column 11.
It is moved and positioned in the Y-axis direction by.

With the above configuration, the processing head 13 is moved and positioned in the Y-axis direction to correspond to the desired position of the workpiece W, and the workpiece W is irradiated with the laser beam LB from the laser oscillator 5, thereby hardening the desired position of the workpiece W. It will be understood that it can be done.

By the way, when performing laser hardening on the surface of the workpiece W, if the reflectance of the workpiece surface is high, it is necessary to perform an appropriate coating treatment on the workpiece surface. Therefore, in this example,
At a side position of the movement area of the work table 3,
A surface coating device 17 is arranged. This surface coating device 17 acts to apply a suitable coating material such as manganese phosphate, carbon powder, silicon carbide, etc. to the desired surface of the workpiece W, and may be composed of, for example, a general coating robot. be.

When performing laser hardening on a desired location of the workpiece W, in order to make the cross-sectional shape of the laser beam LB the desired cross-sectional shape and to make the intensity distribution of the beam approximately uniform within the cross-sectional shape to uniformly perform laser hardening, The processing head 13 is provided with beam deforming means.

More specifically, as shown in FIG. 3, a vertical support plate 19 is provided in the processing head 13, and a laser beam LB oscillated from the laser oscillator 5 is attached to the support plate 19. A first bend mirror 21 that reflects the light downward is attached. Further, near the bottom of the support plate 19, the first
An integration mirror 23 is attached to the bend mirror 21 so that the direction of reflection can be finely adjusted.

The integration mirror 23 changes the cross-sectional shape of the laser beam LB from the laser oscillator 5.
In this example, the purpose is to transform the laser beam LB from a round shape to a square shape, and to make the beam intensity distribution approximately uniform within the cross-sectional shape of the laser beam LB.
A large number of rectangular plane mirrors 27 are mounted on a concave substrate 25. That is, a large number of plane mirrors 27
are appropriately arranged so that the focal plane has a rectangular shape and the beam intensity is uniform. Therefore, in other words, at the focal plane of the integration mirror 23, the laser beam
The cross-sectional shape of the LB is square, and the beam intensity is uniform over the cross-sectional area. Note that the focal length of the integration mirror 23 is set to be large.

In the integration mirror 23,
Support plate 29 supporting concave substrate 25
supports the support plate 1 through a plurality of springs 31 and a plurality of bolts 33, each biased in a different direction.
It is swingably supported by a bracket 35 attached to 9. Further, the support plate 29 is
It is supported by a plurality of micrometers 37 attached to a bracket 35 for fine adjustment. Therefore, by operating the micrometer 37, the direction of reflection of the laser beam LB can be finely adjusted.

Furthermore, a second bend mirror 39 is attached near the top of the support plate 19. This second bend mirror 39 reflects the laser beam LB from the integration mirror 23 vertically downward, and is provided so that the reflection direction can be finely adjusted. The configuration for finely adjusting the second bend mirror 39 includes the integration mirror 23
The configuration is similar to that of .

At the lower position of the second bend mirror 39,
A concave lens 41 is arranged as a collimating means for collimating the laser beam LB. The focal position of this concave lens 41 is aligned with the focal point of the integration mirror 23. Therefore, the laser beam LB passing through the concave lens 41 becomes a parallel light beam with a square cross section and is irradiated vertically downward.

In order to irradiate the laser beam LB onto the peripheral surface of the workpiece W or the inner peripheral surface of the hole H of the workpiece W, a bend mirror 43 is provided at the lower end of the concave lens 41 to horizontally reflect the laser beam LB. A mirror support member 45 is supported so as to be vertically movable and horizontally rotatable.

More specifically, as shown in FIG. 4, a threaded rod 49 such as a ball screw is vertically and rotatably supported on the back surface of the support plate 19 via a bearing block 47. Lifting bracket 53 equipped with a nut member 51 screwed into this threaded rod 49
is guided and supported by a guide member 55 vertically provided on the back surface of the support plate 19 so as to be vertically movable. Therefore, the screw rod 49 and the output shaft are connected,
The lifting bracket 53 is moved up and down by driving a servo motor 57 mounted on the support plate 19.

The mirror support member 45 is attached to a support bracket 59 horizontally attached to the lower part of the lift bracket 53.
is supported. That is, the support bracket 59 extends to a position that crosses the optical path of the vertical laser beam LB, and a through hole 61 is bored at a position corresponding to the laser beam LB. A flange member 65 having a boss portion 63 in the center is attached to the lower surface of the support bracket 59, and a cylindrical outer cylinder member 67 is attached to the lower part of the flange member 65.
is installed. An annular inner cylinder member 69 is rotatably supported inside the outer cylinder member 67.

A driven pulley 71 rotatably supported by the boss portion 63 of the flange member 65 is integrally attached to the upper part of the inner cylinder member 69. A belt 73 that is wound around the driven pulley 71 is wound around a drive pulley 77 that is attached to a motor 75 that is attached to the support bracket 59. An annular member 8 provided with an annular water cooling chamber 79 at the lower part of the inner cylindrical member 69
1 is integrally attached, and the pipe-shaped mirror support member 45 is attached to the lower part of this annular member 81.

A mirror base member 83 made of a material with good thermal conductivity, such as copper, is attached to the lower part of the mirror support member 45, and the bend mirror 43 is supported on this mirror base member 83. In this embodiment, the bend mirror 43 is held at an angle of 45 degrees, and the mirror support member 45
An exit of the laser beam LB reflected by the bend mirror 43 is formed in a part of the mirror 43 .

In order to cool the bend mirror 43, a heat pipe 85 is supported on the mirror support member 45. One end of this heat pipe 85 is
The heat pipe 85 is in contact with the mirror base member 83 and the bend mirror 43, and the other end of the heat pipe 85 faces into the water cooling chamber 79. Therefore,
The bend mirror 43 is effectively cooled.

In the above configuration, the work table 3
After the hole H of the workpiece W placed above and the mirror support member 45 are made to face each other, when the lifting bracket 53 is lowered by driving the servo motor 57,
The lower part of the mirror support member 45 is inserted into the hole H. After inserting the mirror support member 45 into the hole H of the workpiece W and positioning it at a desired position, the laser beam LB is emitted from the laser oscillator 5. After the laser beam LB is transformed into a parallel beam with a rectangular cross-sectional shape, , is incident on the bend mirror 43.
Therefore, it is reflected by the bend mirror 43 and illuminates the inner peripheral surface of the hole H.

When the laser beam LB irradiates the inner peripheral surface of the hole H,
When the motor 75 is driven, the mirror support member 45 is rotated, and the laser beam LB goes around the inner peripheral surface of the hole H. Therefore, the hole H in the workpiece W
It is possible to harden the inner circumferential surface of the

Furthermore, by arranging the mirror support member 45 to face the outer peripheral surface of the workpiece W and irradiating the outer peripheral surface with the laser beam LB while rotating the workpiece W, the outer peripheral surface of the workpiece W can be laser hardened.

As mentioned above, when laser hardening the inner circumferential surface of the hole H of the workpiece W or the outer circumferential surface of the workpiece W, since the laser beam LB is made into a parallel beam, the distance between the bend mirror 43 and the irradiation position of the workpiece W is Even if there is a change, the change in the irradiation width is extremely small, and the irradiation surface is heated uniformly, making it possible to easily perform homogeneous hardening. In addition, since the laser beam LB has a rectangular cross-sectional shape, the hole H in the work W
When hardening the inner circumferential surface or outer circumferential surface of the steel, by making the hardening start position and the hardening end position contact each other without overlapping each other, it is possible to uniformly harden the hardening width and to perform homogeneous hardening.

By the way, when hardening the upper surface of the workpiece W, the mirror support member 45 and the like are configured to be retractable from the optical path of the laser beam LB so that the upper surface of the workpiece W is directly irradiated with the laser beam LB. Just configure it. That is, as shown in FIG. 5, for example, a guide rail member 87 is provided below the lifting bracket 53, and the support bracket 59 is movably supported by the guide rail member 87, and the support bracket 59 is moved. The configuration includes a fluid pressure cylinder 89 for this purpose.

With the above configuration, the mirror support member 45 and the like can be retracted from the optical path of the laser beam LB, and the upper surface of the workpiece W can be directly irradiated with the laser beam LB.

Note that the present invention is not limited to the above-described embodiments, and can be implemented in other embodiments by making appropriate changes. For example, the cross-sectional shape of the laser beam is not limited to a rectangular shape.
It may be formed into an elliptical shape with parallel portions.

[Effects of the Invention] As can be understood from the above description of the embodiments, according to the present invention, the laser beam is parallelized and then irradiated onto the desired position of the workpiece.
The workpiece irradiation width is always approximately constant, and the irradiation surface is uniformly heated. Therefore, uniform hardening can be easily performed without worrying about the focal position of the lens. In addition, when laser hardening the outer circumferential surface of a cylinder or the inner circumferential surface of a hole, the hardening start position and end position do not overlap.
Hardening can be done with uniform width throughout.

[Brief explanation of drawings]

FIG. 1 is a front view of the apparatus according to this embodiment, and FIG. 2 is a plan view thereof. Figure 3 is - in Figure 1.
FIG. 4 is an enlarged cross-sectional view taken along the line, and is a left side view of FIG. 3, with a portion omitted. FIG. 5 is an explanatory diagram of the second embodiment. 3...Work table, 5...Laser oscillator,
13... Processing head, 23... Integration mirror, 41... Concave lens.

Claims (1)

[Claims] 1. A work table that supports a workpiece to be surface-treated, a laser oscillator that oscillates a laser beam to be irradiated to the workpiece, and a cross-sectional shape of the laser beam oscillated from the laser oscillator. a beam deforming means that deforms the beam into a cross-sectional shape having parallel portions and substantially uniformizes the intensity distribution of the beam within the cross-sectional shape; a collimating means that converts the laser beam that has passed through the beam deforming means into parallel beams; 1. A laser surface treatment apparatus comprising: a processing head that irradiates the surface of the workpiece with a converted laser beam. 2. The processing head is characterized by being equipped with a mirror support member that can freely enter into a hole drilled in the workpiece and has a bend mirror near its tip that reflects the laser beam to the inner peripheral surface of the hole. A laser surface treatment apparatus according to claim 1. 3. The laser surface treatment apparatus according to claim 2, wherein the mirror support member is retractable with respect to the optical path of the laser beam.