JPS63224886A - Method and device for dull roll working by laser - Google Patents

Abstract

PURPOSE:To form a dull face in the porous shape and arrangement of optimum hardness by expanding the diameter of the laser beam having specific pulse strength by plural Q switch signals and forming in non-parallel group and focusing on the roll surface and delaying in order the Q switching time. CONSTITUTION:The laser beams LB1-LB4 in specific pulse strength are oscillated by laser oscillators OSC1-OSC4 with the plural Q switch signals Q1-4 transmitted from a Q switch control system 10. Specific divergence angles Q1-Q4 are respectively made by beam expanders BX1-BX4 and convergences FP1-FP2 are effected respectively on a roll surface 20 by a reflection mirror BM, prism MM and condensing lens FL to delay in order the Q switch time by one shot multivibrators OM1-OM4 as well. The roll surface 20 becomes at optimum hardness and in bore diameter depth and its porous arrangement is adequately dispersed to better the roll dull face.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for dulling a roll using laser light.

[Conventional technology]

Roll dulling methods include shot blasting, electrical discharge machining, and a method of machining the roll surface using a laser. Devices for dulling the surface of a roll using a laser are disclosed in, for example, Japanese Patent Publication No. 58-25557 and Japanese Patent Publication No. 6
It is disclosed in Japanese Patent No. 0-2156 and is well known. The apparatus disclosed in Japanese Patent Publication No. 60-21.56 is an apparatus for dulling a roll surface by generating pulsed laser from a light source such as a YAG laser or a ruby laser using a Q switch.

For dull processing of rolls, a predetermined frequency is used.

It is necessary to perform periodic processing on the roll surface using a pulsed laser with a certain pulse width and peak value.

Methods to obtain such pulsed laser output include pulsing continuous wave (CW) laser output with a mechanical optical device (chopper, shutter, etc.), and using pulsed lasers such as pulse excitation or Q-switch pulses. There is a way.

[Problem that the invention seeks to solve]

Since the Q-switch pulse does not require mechanical equipment, it has the characteristics that the equipment can be made smaller and simpler than the former, and at the same time, frequency control is easy and the control range is wide. However, when changing the frequency of the Q switch, the oscillation excitation conditions change, so the pulse waveform, peak output, etc. change at the same time, making stable dull processing impossible. Further, as shown in FIG. 8, the peak value (Pl) of the leading pulse becomes extremely larger than that of the subsequent pulses (P2 +P3 t Pa...).

Furthermore, the condensing diameter in dull processing is determined by the focal length of the condenser lens and the divergence angle of the oscillating laser beam, so controllability is poor and only a constant dull shape can be obtained, and large and small dull shapes are mixed. Processing is difficult.

The above-mentioned Japanese Patent Publication No. 60-2156 does not provide a solution to the above-mentioned problems.

If the peak values of the pulse train differ greatly, the depth of the hole is determined by the first pulse P1, so the effect of P2 to P4 becomes small and the overall controllability of the pulse group is poor. In particular, the hole diameter and depth cannot be controlled to a large extent.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention combines a group of laser beams using a plurality of Q-switched lasers, a Q-switch control system, and a beam expander. The diameter (the product of the beam diameter and the oscillation angle θ is constant; DXθ=constant) is respectively enlarged, the laser beams are combined into a laser beam group, and the Q-switch time of the laser beam group is sequentially delayed. The pulse group has a pulse interval for each laser, and the pulse peak value of each laser is controlled to a predetermined value, and the diameter, depth, and position of dulling are controlled during dulling of the roll surface. = Provides a dull processing method and device.

The method according to the present invention will be explained below with reference to the drawings.

FIG. 1 shows the basic configuration of the pulsed laser control device of the present invention when the number of pulses is four. 08Ct to 03Ca are laser oscillators. Q S 1 to QS4 are Q switches and are set to 08c1 to 08C4. 10 is a Q switch control system, from which Q switch signals Q1~
Q4 is sent out.

Laser beams LBI to LB4 are generated from osci to 08C4. The beam diameters of the laser beams LBj to LB4 are expanded by beam expanders BX1 to BX4, respectively, and the divergence angles of the laser beams become θ1 to θ4.
M6. The laser beams are combined into a bundle of laser beams LBP by the combining mirrors MM1 to MM3.

The laser beam group LBP is condensed by the condensing lens FL, and becomes a condensed laser beam group LFP at the condensing point FPo, which is the same as if - - laser beams had been condensed. 20 is the surface of the roll to be processed.

The condensing diameters d1 to d4 of each laser beam LB1 to LB4 of the laser condensed beam are determined by the respective beam divergence angles 01 to θ4.
and the focal length fl of the condensing lens FL dz = f LX
θ1e d2=flXθ2゜da=fl×θay
The diameter and depth of the hole to be machined by each laser beam can be determined by the focused beam diameters d1 to d4 and the set peak power such that d4=flXθ4.

In FIG. 1, by controlling the beams φ1 to φ6 of the prayer bending mirrors BM1 to BM6 according to the angle formed by a pair of reflecting surfaces of the combining mirror, an angle α is formed between each beam in the combined laser beam group LBP. is a parallel beam of 0° or a finite angle α
It is possible to make a non-parallel beam by

Figure 2 shows laser beams LB1 and LB2, and LB3.
and LB are respectively parallel beams LB12+LB34, and the combined beam angle α is set to α≠0° by the bending mirrors BM5 and BM.

As a result, the parallel beam LB12. The condensing points of the LB34 are shifted to FPl and FP2, respectively, from the point FPo where all the laser beams were parallel.

Although Figure 1 shows an example of four laser beams, the number of laser beams may be any number.As the number increases, the depth of the six increases almost linearly. The number of rolls can be controlled according to the required quality of the surface roughness of the rolls to be dulled.

FIG. 3 shows a specific control circuit of the Q-switch control system 10, and FIG. 4 shows the time relationship of control signals.

FIG. 4 is composed of a pulse generator PG that determines the frequency fO of a pulse group, and one-sided multivibrators M1 to OM that determine pulse intervals T1 to T3 within the pulse group. In FIG. 4, Qn and Qn have opposite polarities.

In Figure 4, each one-shot multivibrator O
M, ~○M4 are each synchronized.

That is, the output signal fO from the pulse generator PG is
Input to clock CK1 of Ml. As a result, the pulse width T1 set by OMl is synchronized with the rising signal of fo.
A pulse Q1 is generated.

At the same time, a signal C having a polarity opposite to that of Ql is outputted and inputted to the clock CK2 of 0M2, and by the same action, Q2. Q2
occurs. The same applies to OMa and OMa Nitsui.

As described above, the frequency fO of the pulse group for dull processing is set by the pulse generator PG, and pulse groups Q1 to Q4 are generated with a certain time delay in synchronization with the leading signal of the pulse group, and the laser beam LBI to Q that implements Q switch control of LB4
Laser pulses P1 to P4 of laser beams LBI to LB4 are generated in synchronization with the switch signal. FP in FIG. 4 indicates the generation time relationship of laser pulses P1 to P4.

FIGS. 5a, 5b, and 5c show the pulse generation situation of the pulse beam group. Figure 5a shows Q-switched laser 1
The pulse train shown in FIG. Figures 5b and 5c show pulse trains according to the invention, generated by the control signals of Figure 4, and Figure 5c shows the pulse trains when OMl and 0M3 are set to a time smaller than the width WP of the pulsed laser. A pulse train is shown.

〔Example〕

Pulse beam control of four Q-switched lasers was performed using the method according to the present invention for rolled dull processing. The pulse beam control conditions of the Q-switched laser are as follows.

LBI~LBa: 2KW fo: 20kl (g TI, T3: 5μ5 T21T4: 20μs FL: 25mn FPL, FP2: 50μm 01+ &2: 3mrad O3+ θ2: 2mrad Roll diameter = 500 Roll rotation speed: 30 0~35Orpm As a result, Holes of various sizes with an inner diameter of 120 μm and an inner diameter of 80 μm were obtained in a pattern as shown in Fig. 6, and the cross-sectional shape was as shown in Fig. 7, with dull machining with a roughness value of 2.5 μm.
The transfer rate to the steel plate was as high as 80%, and the wear resistance of the roll was also improved.

〔Effect of the invention〕

Focused diameter and peak value of each pulse in a pulse group.

Since the irradiation time and irradiation position can be set, it is possible to control the melting and evaporation phenomena of the irradiated object during the hole-drilling process for surface roughening, form holes with appropriate hardness, and control the shape of the hole in two positions. A hole arrangement suitable for dull processing can be obtained, and the effect is great.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a pulsed laser output device according to the present invention, FIG. 2 is a side view showing the state of the focused beam, and FIG. 3 is a block diagram showing a specific control circuit of the Q-switch control system. FIG. 4 is a time chart showing the time relationship of control signals, FIG. 5a is a time chart showing the generation timing of the single pulse laser, FIGS. 5b and 5c are time charts showing the generation timing of the synthetic pulse laser,
FIG. 6 is an enlarged plan view of the roll surface processed by the pulsed laser output device according to the present invention, FIG. 7 is an explanatory diagram showing the plane and cross section of the processed surface, and FIG. 3 is a time chart showing the laser generation timing and pulse waveform.

Claims (2)

[Claims] (1) When dulling the roll surface using a Q-switched laser, the beam diameter of each laser beam oscillated by a plurality of Q-switched lasers and a Q-switched control system is expanded using a beam expander, and the laser beams are parallelized or The laser beams are synthesized as a group of non-parallel laser beams, and the Q-switch time of the group of laser beams is sequentially delayed to form a group of pulses with intervals between the pulses of each laser, and the pulse peak value of each laser is controlled to a predetermined value. A dull roll processing method using a laser, which is characterized by obtaining a dull processing shape and a dull processing position that optimize the dull characteristics of the roll surface. (2) A Q-switch controller consisting of multiple laser oscillators equipped with Q-switches, a pulse oscillator that determines the frequency of the pulse group, and a one-shot multivibrator that determines the pulse interval of the pulse group, and a laser beam expander. and an optical system that focuses a laser beam into a group of parallel or non-parallel laser beams.