JPH03207809A - Laser beam type surface treatment apparatus - Google Patents

Abstract

PURPOSE:To form many fine pits having accurate diameter under independent condition by changing position of condenser lens for laser beam to change beam power density and opening/shutting beam shutter synchronizing with shift of a material to be treated. CONSTITUTION:The laser beam 2 from a laser beam generator 1 is condensed on the material 9 to be treated with a mirror 4 and the condenser lens 5 through a beam shutter 3 to execute surface treatment while shifting the material 9 to be treated with x, y tables 7, 8. In the above laser beam type surface treatment apparatus, position of the condenser lens 5 is changed with a driving device 6 to change the power density of laser beam 2 on the surface of material 9 to be treated. Further, while synchronizing with shift of the material 9 to be treated with a controller 10, opening/shutting operation of the beam shutter 3 and power density changing operation in the driving device 6 are controlled. By this method, on the surface of material 9 to be treated, the fine pit having high accuracy and quenched hardening part are alternately and continuously formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a laser beam type surface treatment device, and in particular, a device that changes the degree of convergence (power density) of a laser beam irradiated onto a material in synchronization with the movement of the material. The present invention relates to a laser beam type surface treatment apparatus that alternately and continuously forms fine pits and quench-hardened areas on the surface of a material.

[Conventional technology]

Conventionally, in order to improve the wear resistance of the sliding surfaces of mechanical parts, treatments such as heat treatment, carburization, and nitriding are performed on the sliding surfaces.

However, these treatments pose problems in the deterioration of the working environment and the management of treatment agents, and in order to further improve the sliding characteristics, it is essential to supply lubricating oil to the sliding parts.

In order to solve the problems of such conventional processing methods, “
A new surface treatment method called "plasma gouging method" has been proposed. The plasma gouging method will be explained based on FIG. 5. In FIG. 5, 51 is the material to be treated;
52 is a plasma torch. The plasma torch 52 advances in the direction of an arrow 55 while spraying a plasma arc 53 onto the surface of the material to be treated 51 . As it travels, it swings at high speed in a direction perpendicular to the direction of travel. The plasma arc 53 described above is a high-density heat source, and according to this, the material to be treated 51
By rapidly heating and rapidly cooling the surface to harden it, and at the same time locally melting and eliminating the surface, a depth of 10 to 10
A large number of fine pits of 0lIIIl can be easily formed. Wear parts treated with the plasma gouging method have many fine pits on their sliding surfaces, so these many pits can hold lubricating oil, which reduces the lubrication of the worn surfaces. Performance is improved and the number of oil-out accidents on worn surfaces can be reduced.

[Problem to be solved by the invention]

Although the plasma gouging method described above is an excellent surface treatment method, it has the following problems.

In the plasma arc generated by a plasma torch, it is difficult to precisely control the diameter, etc., and the size of the pits becomes irregular. In addition, although it is desirable that each pit as an oil reservoir be formed independently, in the plasma oil tank type, the pits tend to be continuous grooves, which reduces the effect of hot rust. .

Plasma arc is rather suitable for processing large parts, and it is difficult to apply it to small precision parts such as hydraulic equipment.

Plasma torches are large in size and are not suitable for processing detailed parts, such as deep holes in materials or the base of flanges and shafts.

The purpose of the present invention was made in view of the above-mentioned problems with the current plasma gouging method. It is an object of the present invention to provide a laser beam type surface treatment device that can alternately and continuously form pit formation and hardened portions in a component.

[Means to solve the problem]

A laser beam type surface treatment apparatus according to the present invention includes a laser oscillator that irradiates a laser beam onto a workpiece in order to treat the surface of the workpiece, and an opening/closing operation that allows or blocks the progress of the laser beam. A beam shutter, a condensing lens that focuses the laser beam on the surface of the material to be treated, a driving means that changes the position of the condensing lens and changes the power density of the laser beam on the surface of the material to be treated, and the object. Consisting of a control means that controls the opening/closing operation of the beam shutter and the power density changing operation of the driving means in synchronization with the movement of the material to be treated, and alternately and continuously forms pits and hardened parts on the surface of the material to be treated. be done.

[Effect]

In the laser beam type surface treatment apparatus according to the present invention, the laser beam is used as a heat source and the power density of the laser beam on the surface of the material to be treated is controlled to continuously perform pit formation and quench hardening. Under the
The position of the condenser lens is changed by the driving means in synchronization with the change in the position of the material to be processed. Furthermore, in order to avoid unnecessary material melting between the formed pits and the quench-hardened portion, a beam shutter is used to interrupt the irradiation of the material to be treated with the laser beam at a predetermined time.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the overall configuration of a surface treatment apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes a laser oscillator, and the laser oscillator 1 outputs a pulsed or continuous wave laser beam 2 of a required energy level. Reference numeral 3 denotes a beam shutter placed on the course of the laser beam at a position close to the laser beam output part of the laser oscillator 1. Opening/closing operations for allowing or blocking the progress of the laser beam in this beam shutter 3 are controlled by the controller 10. It is controlled by the control command signal. 4 is a pending mirror that changes the course of the laser beam 2 by reflection, and 5 is a condenser lens.

A pending mirror 4 guides the laser beam 2 toward the material to be treated.

The condensing lens 5 is driven by a driving device 6 so as to move vertically in the figure along the optical axis of the laser beam.

By making the condensing lens 5 movable in the vertical direction,
It becomes possible to change the spot diameter of the laser beam irradiated onto the surface of the processed material. 7 is an X table, and 8 is a y table, which can be moved in the X-axis direction and the y-axis direction, respectively. The upper surface of the X table 7 has a material 9 to be processed.
is placed. The position of the laser beam spot on the surface of the workpiece 9 can be freely changed within the xy plane by the movement mechanism of the X table 7 and the Y table 8.

The operations of the drive device 6, x table 7, and y table 8 described above are controlled by the controller 10.

Next, a surface treatment method using a surface treatment apparatus using a laser beam having the above structure will be described.

FIG. 2 is a graphical representation of various types of machining and processing that can be performed using a laser beam, with the horizontal axis representing the pulse width and the vertical axis representing the power density. The graph shown in FIG. 2 shows that drilling A1 welding (melting) B1 hardening C can be performed on the workpiece 9 depending on the power density of the laser beam 2 applied to the workpiece 9. For example, if the pulse width (laser beam irradiation time) of laser beam 2 is set to about 10-'@ec,
The power density of 10' W/cm2, 103
As the power density is increased to W/cm'..., the power that used to only dry the surface of the material to be treated at low power densities becomes
Various treatments can be performed in the order of hardening, welding, and drilling. In reality, optimal material processing conditions exist based on a combination of not only power density but also pulse width as shown in the table, but the form of processing is primarily determined by power density. The above explanation is for the case where a pulsed laser is used, but when a continuous laser is used, the same effect can be produced by controlling the irradiation time with the beam shutter 3.

As described above, by changing the power density of the laser beam, the machining operation of the material surface can be changed. In this embodiment, the power density can be arbitrarily set by changing the vertical position of the condensing lens 5 in FIG.
Allows you to change the process. This state will be explained based on FIG.

In Figure 3, (A) and (B). (C) shows the status of three types of machining operations. In each figure, 2 is a laser beam, 5 is a condensing lens, and 9 is a processed material. Figure 3 (A)
The position of the condensing lens 5 is set at a lower position, and the focal position of the laser beam 2 is made to substantially coincide with the surface of the material to be processed 9. In this case, the power density of the laser beam 2 on the surface of the material to be processed 9 becomes maximum, and a heated evaporation state occurs instantaneously at the laser beam condensing point on the surface of the material to be processed 9, thereby forming pits. be able to. Figure 3 (
In B), the position of the condenser lens 5 rises a little, the focal position of the laser beam 2 moves to a position above the surface of the material to be processed 9, and the spot diameter of the laser beam on the surface becomes larger. In this case, the power density on the surface of the material to be processed 9 becomes a little smaller, and the material only melts without evaporating, and when irradiation with the laser beam 2 is stopped, it solidifies again.

This phenomenon is used in welding. In FIG. 3(C), the condenser lens 5 further rises, and the spot diameter of the laser beam 2 on the surface of the material to be treated 9 becomes even larger, while the power density becomes smaller. Therefore, in the state shown in FIG. 3(C), the part of the surface of the material to be treated 9 that is irradiated with the laser beam 2 is only instantaneously heated and does not melt, and then the laser beam 2 is irradiated. When it stops, an emergency order is given and hardening is carried out.

In the present invention, the two states shown in FIGS. 3(A) and 3(C) are used, and the feeding movement of the material 9 to be processed by the X table 7 and the Y table 8 is set alternately between the two states. The condensing lens 5 is periodically moved up and down by the driving device 6 in synchronization with.

In state (B) between (A) and (C) in FIG. 3, the beam shutter 3 is closed to prevent the surface of the material to be processed 9 from melting, and the laser beam 2 is irradiated onto the surface. We are trying to prevent this.

FIG. 4 shows the treated surface of the treated material 9 formed by applying the above surface treatment method. The material to be processed 9 is set to move in the direction of the arrow. Also solid line 20
and broken lines 21 indicate the spot shapes of the laser beam 2 irradiated in synchronization with the movement of the workpiece 9 ■, ■, ■...
The irradiation shall be performed in the following order. Also, ■ indicates the first beam scanning line, and ■ indicates the second beam scanning line.

In the above, the irradiation of ■, ... in Figure 4 is shown in Figure 3 (
The irradiation is in the quenching mode (quenching hardening) shown in C), and the irradiation in the drilling mode (pit formation) shown in FIG. 3(A) is irradiation. In this way, by repeatedly moving the condensing lens 5 up and down in synchronization with the movement of the material 9 to be treated, the quench hardening 21 and the pit formation 20 are alternately and continuously formed on the surface of the material 9 to be treated. do. Between hardening and drilling, that is, in the middle of the vertical movement of the condensing lens 5, there is a melting mode shown in FIG. Quality deteriorates. Therefore, in the intermediate process, the beam shutter 3 is closed to interrupt the beam irradiation to the surface. When the above processing is repeated and completed for scanning line I, the scanning line is then moved to (2) and the above processing operations are performed in the same manner. In this way, a large number of fine pits are formed on the hardened surface of the material 9 to be treated.

In the embodiment shown in FIG. 4, the cross-sectional shape of the laser beam 2 is circular, but for example, in the configuration shown in FIG. By arranging the mask member, the shape of the laser beam 2 irradiated onto the material to be treated 9 can also be made into a rectangular hole shape.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the following effects can be obtained.

Using a laser beam as a heat source, while irradiating the material with the laser beam, the condensing lens is moved up and down and the beam shutter is opened and closed to control the power density on the surface of the material to form pits and harden the material. Therefore, the diameter and depth of the pits can be finely adjusted, and any pit density and pit diameter can be achieved depending on the sliding conditions. Since the pits can be formed independently one by one, the reproducibility of the lubrication properties is better compared to the plasma gouging method. In addition, since it uses a laser beam, it is possible to perform fine processing, making it suitable for processing precision and small objects. It can also irradiate narrow areas, so it can be used to treat objects with complex shapes. can also be easily applied.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a surface treatment apparatus according to the present invention;
The figure is an explanatory diagram showing the relationship between the power density of the laser beam and the processing work. Figure 3 is an explanatory diagram showing the relationship between the size of the laser beam spot on the surface of the material to be treated and the processing work. 5 is a surface view of a material to be treated showing the state of surface treatment by the surface treatment apparatus according to the present invention, and FIG. 5 is a perspective view for explaining the conventional plasma gouging method. [Explanation of symbols] 1...Laser oscillator 2...Laser beam 3...Beam shutter 4...Pending mirror 5...Focusing Lens 6...Drive device 7●◆●・●●X table 8...Y table 9...Workpiece 10...Controller

Claims (1)

[Claims] (1) A laser oscillator that irradiates a laser beam onto the workpiece in order to treat the surface of the workpiece, a beam shutter that performs an opening/closing operation to allow or block the progress of the laser beam, and the workpiece a condensing lens for condensing the laser beam on the surface of the material; a driving means for changing the position of the condensing lens to change the power density of the laser beam on the surface of the material to be treated; Control means for controlling the opening/closing operation of the beam shutter and the power density changing operation of the driving means in synchronization with the movement of the material to be treated, and alternately and continuously forming pits and hardened parts on the surface of the material to be treated. A laser beam type surface treatment device comprising: