JPH0349673B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention provides a method for applying a pulsed laser beam to the surface of a workpiece such as a rolling roll.
Regarding the improvement of a laser dull processing machine for performing dull processing to form a precise pattern with many minute irregularities, especially for the rotational drive of the workpiece and the rotational drive of the chopper disk for pulsing the laser beam. The present invention relates to a method for stabilizing the accuracy (ie, roughness) of the pitch of unevenness formed on the surface of a workpiece even if there is variation.

[Prior art] Shot blasting and electrical discharge machining have traditionally been used as dulling methods to form minute irregularities on the surface of rolls, but in recent years, laser beam pulses have been applied to the surface of rolls. irradiate it in the shape of
A method of forming countless irregularities on the surface of a roll is attracting attention. (For example, see Japanese Patent Application Laid-open No. 55-94790.) This method using a laser beam differs from conventional shot blasting and electrical discharge machining in that it
The resulting unevenness pattern is characterized in that the size of each unevenness is uniform over the entire surface of the roll, and the pitch of adjacent unevenness is constant.

When an annealed cold-rolled steel sheet is temper-rolled using a roll that has been dulled by such a laser beam, the regular uneven pattern of the roll surface is transferred to the steel sheet surface, making it difficult to perform conventional shot blasting or electrical discharge processing. Various superior properties can be obtained compared to random patterns obtained through processing.

An example of a conventional laser dull processing machine is shown in FIGS. 4 and 5.

In the figure, reference numeral 1 denotes a rolling roll, which is a workpiece to be dulled, and is rotatably supported by support stands 2 and 3. Reference numeral 4 denotes a drive motor, which applies rotational force to the support base 3 via a power transmission section 5 to rotate the rolling roll 1. 6 is a base on which the above-mentioned parts 2 to 5 are installed.

Reference numeral 7 denotes a laser oscillator, which is mounted on a support 11 on a cart 10 movable on rails 9 provided on a base 8.
It is attached to a mounting base 12 provided through. The rail 9 is provided parallel to the axis of the mill roll 1 so that the carriage 10 can move parallel to the surface of the mill roll 1. 13 is a light guide tube for a laser beam, and a laser oscillator 7
The laser beam emitted from the condensing lens 14
This light guide tube 13 forms a passage leading to
A reflecting mirror 15 is provided inside the bent portion of the laser beam to reflect the laser beam and project it onto the surface of the rolling roll 1 through a condensing lens 14. This light guide tube 13 is also attached to the mounting base 12.

On the other hand, a mounting base 17 is provided on a column 16 erected on the truck 10 so as to be movable up and down via brackets 18 and 19. 20 is a drive motor, 21,
Reference numeral 22 denotes pulleys, each of which transmits the rotation of the drive motor 20 to the chopper disc 25 via belts 23 and 24, causing it to rotate at high speed. Reference numeral 26 designates an assist gas nozzle that sprays an oxidizing gas (assist gas) such as O ₂ , and is attached to the mounting base 12 via a nozzle support portion 27 .

As shown in FIG. 6, the chopper disk 25 is provided with a large number of slits 25a around its outer periphery, and the laser beam passing through the slits 25a is cut into pieces by the high speed rotation of the chopper disk 25. , pulse.

On the other hand, while the rolling roll 1, whose axis is supported by the support stands 2 and 3, is rotated, the pulsed laser beam is projected onto the surface of the rolling roll 1, and countless minute holes are drilled into the roll to form a precise pattern. It is starting to form. The assist gas nozzle 26 is attached to the mounting base 12 via a nozzle support part 27, and sprays assist gas from the vicinity of the tipper disk 25 to the laser beam irradiation position on the surface of the rolling roll 1. This is provided for the purpose of making the shape of the minute recessed hole formed by the hole uniform and having the necessary depth.

By the way, in the case of such a laser dull processing machine, when forming a minute unevenness pattern on the surface of a workpiece such as the rolling roll 1, the distance (pitch) between adjacent depressions is determined in addition to the size of the depressions. Although this is an important control item, the desired pitch is usually obtained by setting a predetermined ratio between the rotational speed of the workpiece and the rotational speed of the chopper disk 25.

[Problem that the invention seeks to solve]

However, in such a conventional laser dull processing machine, the pitch of the concave portion is simply controlled by setting the rotation ratio between the workpiece and the chopper disk 25 to a predetermined value. No consideration was given to variations in the recess pitch during processing.

A conceivable way to solve this problem is to independently control the drive motor 4 for rotating the workpiece and the drive motor 20 for the chopper disk 25 through feedback control.

However, the workpiece is heavy compared to the Chiyotsupa disc 25 (10t for the rolling roll 1).
(before and after), the inertial force is significantly different. That is,
Although it is possible to precisely control the rotation of the chopper disc 25, there is a problem in that the response to the workpiece is very poor and the rotation cannot be controlled precisely. Furthermore, when such independent control is performed, there is a problem in that errors are added and the pitch of the recesses may be greatly disturbed.

This invention was made in view of these conventional problems, and an object of the present invention is to provide a surface roughness stabilization method that can accurately control the pitch of recesses when dulling is performed using a laser dulling machine. That is.

[Means and actions to solve the problem]

Therefore, the method for stabilizing the surface roughness of a laser dull processing machine according to the present invention rotates the workpiece on a rolling roll, and at the same time, the laser beam output from a laser oscillator is transmitted through a chopper disk rotationally driven by a drive motor. In a laser dull processing machine that pulses a laser beam and irradiates the workpiece surface with the pulsed laser beam to form a concave-convex pattern on the workpiece surface, the concave pitch of the concave-convex pattern formed on the workpiece surface is is detected, and the drive motor for rotationally driving the chopper disk is controlled based on the detected value, thereby improving the accuracy of the concave pitch of the workpiece (that is, stabilizing the surface roughness). ).

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

The configuration of the laser dull processing machine shown in FIGS. 4 and 5 described above can be applied as is to this invention.

In FIG. 1, a rolling roll 1, a drive motor 4 for driving the rolling roll 1, and a chopper disk 25 are shown.
The drive motor 20 for driving the chopper disk 25 is the same as that shown in FIGS. 4 and 5 described above.

29 is VVVF (Variablc Voltage Variable
This is a frequency control device that controls the drive motor 4 based on the rotation speed command value h.

Reference numeral 30 denotes a rotation speed sensor, which outputs a voltage signal b corresponding to the rotation speed of the drive motor 20. Also,
Reference numeral 31 denotes a control device for the chopper disk consisting of a DC servo amplifier, which inputs the deviation between the output voltage b of the rotational speed sensor 30 and the voltage g corresponding to the set rotational speed, and generates a control signal d corresponding to this. The rotational speed of the drive motor 20 is outputted and feedback control is performed so that the rotational speed of the drive motor 20 becomes the set rotational speed.

On the other hand, numeral 32 is a recess pitch sensor which detects the pitch of the recesses on the surface of the roll 1 which have been perforated by the laser beam pulsed by the chopper disk 25 immediately after the perforation. Also, 3
3 is a V/F converter, and a rotation speed sensor 30
Convert the output voltage b from to a frequency. Furthermore, 34 is a PLL (Phase Locked Loop),
Frequency a signal from recess pitch sensor 32 and V/
The frequency signal from the F converter 33 is input, and the deviation i between the two is calculated by the chopper disk control device 31.
Output to.

For example, as shown in FIG. 2, the recess pitch sensor 32 uses a measuring laser beam different from the processing laser beam to the rolling roll 1 after processing.
By irradiating the surface of the recess and detecting its reflection intensity in time series as shown in FIG. 3, the time T corresponding to the recess pitch can be determined. In FIGS. 2 and 3, a recess pitch sensor 32a shown by a solid line illuminates a recess formed in the rolling roll 1.
Further, the recess pitch sensor 32b indicated by a broken line irradiates the surface of the rolling roll 1 that is not processed. And the recess pitch P _L is the roll radius R
(mm), roll rotation speed N ₁ (rpm), chipotsupa disk rotation speed N ₂ (rpm), and number of teeth on the chipotsupa disk n, calculate as P _L = 2πRN ₁ /nN ₂ = 2πRN ₁ T / 60 be done.

Next, the operation of the above embodiment will be explained.

In Figure 1, normally the rotational speed command value n is
This is input to the VVVF control device 29, which controls the drive motor 4 and drives the rolling roll 1 to rotate at a predetermined rotation speed h.

On the other hand, the tipper disk 25 is rotationally driven by the drive motor 20, and the slit 2 of the tipper disk 25 is rotated.
The surface of the rolling roll 1 is irradiated with a pulsed laser beam 5a to perform dull processing in which recessed portions are formed. At this time, the drive motor 20
The rotational speed is detected as a voltage b by the rotational speed sensor 30, and this voltage signal b is compared with the voltage signal g corresponding to the set rotational speed. Based on the deviation, the drive motor is 20
is subjected to feedback control, and the chopper disk 25 is driven to rotate at a set rotational speed g.

Therefore, the pitch P _L of the recesses formed on the surface of the rolling roll 1 is as shown in the above formula, N ₁ = h, N ₂
= g.

Now, if there is a fluctuation in the rotation of the drive motor 20 that rotationally drives the chopper disk 25, the rotation speed including the knitting is detected by the rotation speed sensor 30, and the detected value b is compared with the set value g, Based on the deviation, the drive motor 20 is feedback-controlled by the control signal d via the chopper disk control 31, and the chopper disk 25 reaches a predetermined rotation speed g.
The recess pitch is set to a predetermined value.

In addition, if the rotational speed of the drive motor 4 that rotationally drives the rolling roll 1 changes, the recess pitch frequency a detected by the recess pitch sensor 32
A deviation i occurs between the frequency and the frequency from the V/F converter 33, and the drive motor 20 is controlled by the control signal d output from the chopper disk control device 31 based on this deviation i. The pitch of the concave portion formed in 1 becomes a predetermined value.

In addition, if rotational fluctuations occur simultaneously in both the drive motor 20 on the chopper disk 25 side and the drive motor 4 on the rolling roll 1 side, the deviation between the set rotation speed g and the detected rotation speed b, and the frequency and detection frequency The deviation from a is added in the chopper disk control device 31, and the drive motor 20 is controlled using this added value as a control signal d, thereby controlling the recess pitch of the rolling roll 1 to a predetermined value.

In this way, not only when the drive motor 20 that drives the tipper disc 25 fluctuates, but also when the drive motor 4 that rotationally drives the rolling roll 1 with a large inertial force changes.
Even when there is a change in the pitch, the drive motor 20 on the chopper disk 25 side is controlled so that the pitch of the recesses formed in the rolling roll 1 is controlled to a predetermined value.
Therefore, since the inertial force of the chopper disk 25 is small, even if there is a rotational fluctuation in either or both of the chopper disk 25 and the rolling roll 1 at the same time, the fluctuation can be absorbed with a good response and the recess pitch can be maintained at a predetermined value. controlled so that

Next, to describe an actual processing example, in order to obtain a concavo-convex pattern with a recess pitch of 0.3 mm on a temper rolling work roll with a roll radius of 555 mm, the roll rotation speed was 124 rpm and the chopper rotation speed was
The machining conditions were set to 7200 rpm. At this time, the number of teeth of the tipper disk 25 is 200.
When drilling was performed under these conditions, the recess pitch was within ±10%.

〔Effect of the invention〕

As explained above, according to the method for stabilizing the surface roughness of a laser dull processing machine according to the present invention, the workpiece is rotated, and the laser beam output from the laser oscillator is rotated by the chipper circle which is rotationally driven by the drive motor. A laser beam is pulsed by a plate, and the pulsed laser beam is irradiated onto the workpiece surface to form an uneven pattern on the workpiece surface. The structure is characterized in that the pitch of the recesses in the uneven pattern is detected and the drive motor for rotating the chipper disk is controlled based on the detected value, so that the pitch of the recesses formed on the surface of the workpiece is controlled. The accuracy is improved, the configuration of the control device is simple, and the equipment cost is low.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of an embodiment of the method for stabilizing the surface roughness of a laser dull processing machine according to the present invention, FIG. 2 is a diagram showing the relationship between the recess pitch sensor and the unevenness of the rolling roll, and FIG. The figure shows an output signal waveform diagram of the concave pitch sensor, FIG. 4 is a plan view of an example of a laser dull processing machine according to the conventional and the present invention, FIG. 5 is a side view of FIG. 4, and FIG. 6 is a diagram of a chopper disk. FIG. 1... Roll roll (workpiece), 4... Drive motor, 7... Laser oscillator, 13... Light guide tube,
14...Condenser lens, 15...Reflector, 20...
Drive motor, 25... Chiyotsupa disk, 29...
VVVF (Variable Voltage Variable
Frequency) control device, 30...rotation speed sensor,
31... Control device for Chiyotsupa disk, 32, 32
a, 32b...Recess pitch sensor, 33...V/
F converter, 34...PLL (Phase Locked
Loop).

Claims (1)

[Claims] 1. While rotating a workpiece such as a rolling roll, a laser beam output from a laser oscillator is pulsed by a chopper disc rotationally driven by a drive motor, and the pulsed laser beam is applied to the surface of the workpiece. In a laser dull processing machine that irradiates the workpiece to form an uneven pattern on the surface of the workpiece, the pitch of the recesses of the uneven pattern formed on the surface of the workpiece is detected, and the chipper disk is formed based on the detected value. A method for stabilizing surface roughness of a laser dull processing machine, comprising controlling the drive motor for rotational driving.