JPH01254392A - Dull working method for product surface - Google Patents

Abstract

PURPOSE:To make dull working efficient by projecting and compounding the two laser beams oscillated from two oscillators to a beam splitter and converging them at two places of the roll surface as two co-axial laser beam group. CONSTITUTION:One part of a beam LB1 of the two laser beam LB1, LB2 oscillated from two oscillators OSC1, OSC2 with controlling by a switch control device 10 is projected to a beam splitter BS via a reflection mirror BM1 and the other part LB2 directly. It is here compounded, converged on the converging face FP1 of the roll surface as a co-axial laser beam group LBP1 and dulling is executed. One part of a compound light LBP2 is converged on another converging point FP2 and the dulling of the roll surface at another position FP2 is executed. The working of good accuracy can be executed and the device can be miniaturized because the control of the peak value setting of an individual pulse and the pulse interval are enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for dulling the surface of a product such as a roll using laser light, and particularly to a method for dulling the surface of a product such as a roll using laser light, and in particular to a method for controlling pulsed laser beam synthesis.

[Prior Art] As a method for dulling a roll, there are a shot blasting method, an electric discharge machining method, and a method of processing the roll surface using a laser.

Regarding the device for dulling the roll surface using a laser, Japanese Patent Publication No. 5B-25557 and Japanese Patent Publication No. 60-215
It has been announced by No. 6. The device described in Japanese Patent Publication No. 60-2156 is a device that uses a light source such as a YAG laser or a ruby laser to generate a pulsed laser using a Q switch to dull the roll surface. (hole size, depth, hole diameter). In other words, multiple pulses are used because the height of the dull shape is too low and proper dulling cannot be achieved with a single pulse.

Therefore, in dulling the roll surface, it is necessary to periodically process the roll surface using a pulsed laser having a predetermined frequency, pulse width, peak value, etc. There are two ways to obtain such a pulsed laser output: pulsating continuous wave (CW) laser output using a mechanical optical device (chopper, shutter, etc.), pulsed laser excitation such as pulsed excitation or Q-switch pulse, or There is a method using a pulse laser such as a Q-switch pulse.

Since Q-switched pulses do not require mechanical equipment, Ii
Compared to the η type, the device is smaller and simpler, and at the same time, frequency control is easy and the control range is wide. However, when the Q switch changes the frequency, the oscillation excitation conditions change, so the pulse waveform, peak output, etc. change at the same time, making stable dull processing impossible. Also, as shown in Fig. 2, the peak value (4) of the peak pulse or the subsequent pulse (P2, 113.114, . . .
) becomes extremely large.

Furthermore, Japanese Patent Publication No. 60-2156 does not disclose any solutions to the above-mentioned disadvantages.

[Problem to be solved by the invention] If the peak values of the pulse train differ greatly, the first pulse P1
Since the depth of 6 is determined by , the effect of P2 to P4 becomes small, and the controllability as a comprehensive pulse group is not good, so this problem needs to be solved.

The present invention aims to solve these problems.

[Means for Solving the Problems] In order to achieve the above object 1, the present invention uses a plurality of pulse lasers, a pulse generation control system (Q switch control system in the case of a Q switch laser), and a beam splitter. For dull processing, the laser beam group is synthesized and the pulse peak value of each laser is controlled using the current value of the excitation lamp of the laser oscillator, thereby configuring a pulse group suitable for dull processing of the roll surface. A suitable pulsed laser control method is provided.

That is, the gist of the present invention is to provide a method for dulling the surface of a product using a pulsed laser, in which a laser is oscillated from a set of two laser oscillators each having a pulse peak value set individually, and the surface to be machined is This method of dulling the surface of a product is characterized by separating the individual laser components and coaxially combining them on the way to reach the target surface, and then irradiating the processed surface with the laser at predetermined intervals.

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

[Function] The beam splitter here refers to an optical element that has the function of separating incident light into reflected light and transmitted light when light in a certain wavelength range is incident at a certain specific angle. . Generally, these optical elements have a structure in which several types of substances having different refractive indexes are laminated as a multilayer film on the surface of a Fu material such as quartz. Also, due to the characteristics of the multilayer structure, it is possible to simultaneously polarize the reflected light and the transmitted light; in this case, 1. The transmitted light of B1 becomes a polarized light component (P wave) parallel to the incident plane of LIll, and the reflected light of L112 becomes a horizontally polarized light component (S wave).

FIG. 1(a) shows the basic configuration of a pulsed laser control device in the case of a two-pulse tree suitable for carrying out the method of the present invention. 05CI and 05C2 are laser oscillators. QSI,
QS2 is a Q switch, and the oscillator 0501゜05C2
is set to . 10 is a Q switch control system, from which Q switch signals Ql and Q2 are sequentially sent out;
Accordingly, laser beams 1.111.1 and B2 are generated from the oscillations H4osc+ and oscz. Laser beam L
B 2 directly connects the laser beam L [ll is the bending mirror B
into the beam splitter-IIs via the MI, and the LB
Transmitted light LBI (T) of I and reflected light LB2 of L[12
(It) are synthesized as a coaxial laser beam group LBI'I.

On the other hand, in the other direction of the beam splitter BS, LB2
The transmitted light LB2 (T) and the reflected light LBI (I
t) are combined into a coaxial laser beam group LBP2.

The laser beam groups LBPI and LBP2 are focused by condenser lenses FLI and l1L2, respectively. Focus point FP
I.

In FP2, the laser focused beam group LBP I, LBP is the same as if one laser beam was focused.
2, which enables high-speed dulling of the roll surface by dividing the roll into two.

In FIG. 1(b), only the laser beam group LBP2 combined by the beam splitter is used, and the other laser beam LBP2 is used.
B 11 + is absorbed by the beam damper 11D and is not used. In this case, the dulling speed is halved compared to that in FIG. 1(a).

20 is the surface of the roll to be processed. As the number of holes increases to two, the depth of the hole becomes almost twice as deep, and the number of holes is selected according to the required quality of the surface roughness of the roll to be dulled.

Figure 3 shows the ideal pulse waveform when performing roll surface dulling, where τ0 is each pulse width, and τ1 is the peak pulse +1
This is the interval between L l and the second pulse PL2. As shown in FIG. 3, the ideal pulse waveform suitable for rolled dull processing is PLI=PL2.

Using the polarization splitting function of the beam splitter, the laser beam L[lI, LB2 is randomly polarized,
If the P waves and S waves are 50% each, the powers of the laser beams l[lI, I, +12 should be the same, and the beam splitter's unique angle of incidence (the P waves and S waves can be completely separated) By setting the angle of incidence), it is possible to set PLI = PL2.

Laser beam 1. If Bl, L[12 is not a completely random deflection and P waves and S waves cannot be separated by 50%, PLI =PL2.

Next, the specific control circuit of the Q switch control system IO will be explained in the fourth section.
In addition, the time relationship of the control signals is shown in FIG.

In FIG. 4, it is composed of a pulse generator RYPG that determines the frequency of a pulse group of 1°, and a one-shot vibrator OMI and 0M2 that determines a pulse interval of 1 in the pulse group, and in FIG. Each OMI and 0M2 are synchronized with the rise signal of the respective Jinkai-3.

That is, the output signal f from the pulse generator PG. OM
Manually input 1 to clock C of +. This)te r.

Pulse width τ1 set by OM+ in synchronization with the rising signal of
A pulse Ql is generated, and at the same time a signal with the opposite polarity to Ql is generated.

As described above, the frequency of the pulse group for dull processing "." is set by the pulse generator PG, and a pulse group is generated with a certain time delay in synchronization with the leading signal, LDI, L[12
Q-switch control can be implemented. Also,
If τ1 is set to 0, both pulses can be applied simultaneously.

Figure 6 is a diagram showing beam combination, and Figure 6(a) shows beam combination using a beam splitter to produce a human-powered laser beam LB.
Incident angle θ8 between I and LB2. By setting θ2 to be the same within the eigenvalues of the beam splitter, the transmitted light of L[11 and the reflected light of LB2 can be made into a coaxial combined beam LPB. FIG. 6(b) is a diagram of beam combination by the total reflection mirror TM. In this case, the human-powered laser beam L[l
Although I and LB2 can be combined in parallel, they cannot be combined coaxially, and the diameter of the combined beam LPB becomes large, which has the disadvantage that the lens of the condensing system becomes large.

Note that the object to be laser processed is not limited to the roll surface, but may be any general product. Also,
The type of laser used for processing is a solid laser such as YAG or ruby.

[Example] Roll dull processing was carried out by controlling the pulse waveforms of two Q-switched lasers using the method according to the present invention. The pulse waveform control conditions of the Q-switched laser are as follows.

Beam splitter - 2 inch diameter laser beam. : 300nsecτI =5μ5
ec fo: 20kllz Lens focal length FL: 25mm Roll shape Length: 1500mm Diameter: 600mm Processing time: about 1 hour As a result, the processing time was about 1 hour, which was fast, and the hole shape had an inner diameter of 1001 and a roughness value of 2. B+M dull processing was obtained, the transfer rate to the steel plate surface was as high as 80%, and the wear resistance was also improved.

[Effects of the Invention] According to the method of the present invention explained above, pulsed laser beams can be combined coaxially, so the condensing system using lenses becomes small and simple, and alignment at the condensing point becomes easy. .

Furthermore, since the peak value can be set individually for each pulse in the pulse group, it is possible to control the melting and evaporation phenomena of the irradiated object in the hole-drilling process for surface roughening, and to form holes with appropriate hardness. Moreover, since the pulse interval of the pulse group can be controlled, it is possible to perform hole machining more suitable for dull machining, which is highly effective.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are block diagrams showing the configuration of the darning system according to the present invention, FIG. 2 is a waveform diagram showing the state of the laser output of a pulse group using a Q switch, and FIG. Figure 4 is a block diagram showing the control circuit of the Q-switch control system, Figure 5 is a timing chart showing the time relationship of control signals, and Figure 6 is a waveform diagram showing the output state of the pulse group. FIG. 3 is a diagram illustrating beam combining, in which (a) illustrates beam combining using a beam splitter, and (b) illustrates beam combining using a total reflection mirror.

Claims (1)

[Claims] In the method of dulling the surface of a product using a pulsed laser, the laser is emitted from a set of two laser oscillators with individually set pulse peak values, and the individual laser components are separated on the way to the processing surface. A method for dulling the surface of a product, which is characterized by performing coaxial synthesis and irradiating the processed surface with a laser at predetermined intervals.