JPH06122084A - Method for controlling laser beam machine - Google Patents

Abstract

PURPOSE:To machine with a laser beam more precisely over a total length of a subject to be machined by controlling a position of machining head with a preliminarily stored profile data of the subject to be machined. CONSTITUTION:In a laser beam machining device having a main shaft bed 2, a laser beam machining head 7 and a position sensor 12, and machining by controlling so that an interval between the laser beam machining head 7 and a surface to be machined is kept in a specified value based on a signal of the position sensor, against the territory that the position sensor 12 can not detect, the position of the laser beam machining head 7 is controlled based on the profile data preliminarily inputted. In such a way, the machining can be steadily executed also even on the portion so as to be made impossible for machining because a size of area to be measured opposing to the position sensor 12 is not enough, and the highly precise machining over the total length of the subject to be machined can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a laser processing apparatus for forming fine irregularities and holes on the surface of a cylindrical rotating body for use in rolling rolls and the like.

[0002]

2. Description of the Related Art A technique for forming fine irregularities on a surface of a cylindrical body or forming fine holes with a laser beam is known.
It has already been put into practical use (Japanese Patent Laid-Open No. 11285/1990,
See JP-A-55-94790). Since the processing accuracy in such a laser processing apparatus depends on the accuracy of the focal length of the laser light, it is necessary to always keep the distance between the condenser lens and the surface to be processed within a predetermined range during the processing operation. is there.

As a method for keeping the distance between the condenser lens and the surface to be processed constant, for example, an electromagnetic position (distance) sensor is provided at a position adjacent to a laser processing head having a condenser lens built therein, and this position sensor is used. It is known that the position adjustment control of the laser processing head is performed by feedback control based on the output of the laser.

[0004]

However, it is practically impossible to dispose the laser processing head and the position sensor at the same position, and the sensitivity characteristic of the position sensor makes it possible to face the sensitive portion of the position sensor. If the area of the measurement surface is insufficient, it will not be possible to obtain the required signal. Therefore, in particular, in the case of a roll having a diameter difference between the central portion and the axial end portion in consideration of the difference in thermal expansion, the distance between the condensing lens and the processed surface at the axial end portion is Since it cannot be measured by the position sensor, the distance between the condenser lens and the surface to be processed cannot be maintained at a predetermined accuracy.

The present invention has been devised in order to eliminate such disadvantages of the prior art, and its main purpose is that the area of the position sensor facing the surface to be measured cannot be sufficiently obtained. It is an object of the present invention to provide a method for controlling a laser processing apparatus that is improved so that stable processing can be performed even on a portion that cannot be processed.

[0006]

According to the present invention, such a purpose is to provide a spindle bed for rotatably supporting and rotatably driving a shaft of a workpiece, which is a cylindrical body, and a workpiece. A laser processing head having a laser processing head mounted on a table movable along a rotation axis so as to be able to come in contact with and separate from the processing surface, and a position sensor for detecting the position of the processing surface. A laser processing apparatus for continuously performing laser processing on a surface to be processed in a circumferential direction and an axial direction while controlling the distance between the surface to be processed and a surface to be processed based on a signal from a position sensor. Then, in the region where the position sensor cannot detect, the gap adjustment control between the laser processing head and the surface to be processed was performed in the region where the position sensor can detect the setting of the proper distance between the laser processing head and the surface to be processed. Later, the workpiece to be stored in advance It is accomplished by performing in accordance with the profile data.

[0007]

According to this structure, the distance between the machining head and the surface to be machined is adjusted to an appropriate value at a site that can be detected by the position sensor, and then the object to be machined is stored based on the profile data stored in advance. The distance adjustment control between the processing surface and the laser processing head is performed. That is, a portion that cannot be detected by the position sensor is processed by approximate numerical control.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 shows a laser processing apparatus constructed according to the present invention. This device has a structure similar to that of a lathe, and corresponds to a spindle bed 2 for rotatably supporting and rotationally driving a roll 1 as a workpiece, and a feed device for a tool rest of the lathe. The movable table 3 is used to mainly perform a process of continuously forming fine holes at regular intervals on the roll surface 1a.

The moving table 3 includes a fixed bed 4 fixed on the floor, an X-axis table 5 horizontally moving on the fixed bed 4 in a direction parallel to the rotation axis of the roll 1, and an X-axis table 5 on the X-axis table 5. A Y-axis table 6 that moves back and forth in a direction orthogonal to the rotation axis of the roll 1, and a laser processing head 7 with a built-in condenser lens, a beam expander 8, and a laser oscillator 9 are mounted on the Y-axis table 6. is doing. The X-axis table 5 automatically controls the lateral feed pitch of the laser processing head 7 in synchronization with the rotation of the roll 1, and the Y-axis table 6 sets the initial position of the distance between the roll 1 and the laser processing head 7. It is like this. The spindle bed 2 and the moving table 3 themselves can use the structure of a known machine tool, and are not directly related to the essence of the present invention, so a detailed description thereof will be omitted.

As shown in FIG. 2, a follow-up table 11 driven by a servo motor 10 in the same direction as the moving direction of the Y-axis table 6 is mounted on the Y-axis table 6. The position sensor 12 is mounted on the tracking table 11 together with the laser processing head 7.

The laser processing head 7 and the position sensor 12 are arranged so that the centers of the surfaces of the laser processing head 7 facing the roll surface 1a are adjacent to each other with a predetermined distance L on a common plane where the rotation axes of the rolls 1 are orthogonal to each other. Installed. Moreover, the position sensor 12 is placed on the front side in the rotation direction of the roll 1 (arrow A in FIG. 2).

In the present apparatus, by rotating the roll 1 at a predetermined speed and irradiating the roll surface 1a with a laser spot in a pulsed manner, a fine phantom line having a predetermined lead angle is formed on the spiral virtual line. Processing is performed to continuously drill large holes. Here, the accuracy of the hole diameter depends on the focal length, that is, the dimensional accuracy of the distance between the condensing lens (not shown) built in the laser processing head 7 and the roll surface 1a. There is a need to.

The position sensor 12 is composed of a non-contact type electromagnetic proximity sensor utilizing an eddy current and the like, and produces an analog output proportional to the distance dimension with the roll surface 1a. This analog output is converted into a digital output by the A / D conversion unit 13 and input to the positioning unit 14. In the positioning unit 14, a deviation between a value corresponding to a proper focal length measured in advance (proper distance data between the roll surface 1a and the laser processing head 7) and an actual distance dimension detected by the position sensor 12 is detected. Is calculated and the required movement amount is output to the servo driver 15. The servo motor 10 is driven in accordance with this movement command, and the displacement in the direction orthogonal to the axis of the roll 1 is applied to the follow-up table 11, whereby the distance between the roll surface 1a and the laser processing head 7 is maintained at a specified value. .

The laser processing head 7 and the position sensor 1
As described above, 2 is placed adjacent to each other on a common plane in which the rotation axes of the rolls 1 are orthogonal to each other. However, when the lead angle of the imaginary line is extremely small, the laser processing head 7 It can be said that the deviation between the center of the position sensor 12 and the virtual line can be ignored.

On the other hand, as shown in FIG. 3, when both ends of the roll 1 in the axial direction are larger in diameter than the central part, both ends of the roll 1 in the axial direction and a portion where the curvature of the contour changes (see FIG. 3). Areas B to C and D to E) are position sensors 12
Since the area of the roll surface 1a facing the sensitive section of 1 becomes small, an accurate distance signal cannot be obtained. Therefore, in the present invention, it is assumed that the profile data of the roll 1 stored in advance is used for the control of the follow-up table 11 in the region where the signal of the position sensor 12 becomes unreliable. There is.

First, the follow-up table 11 is positioned at a portion (point A) that can be detected by the position sensor 12, and the laser processing head 7 is adjusted so that the distance between the roll surface 1a and the laser processing head 7 becomes an appropriate value. To position. At the same time, the output value (appropriate interval data) of the position sensor 12 at this time is stored in the follow-up data memory in the positioning unit 14.

Next, the laser processing head 7 is moved to the processing start point (B) by the X-axis table 6 to start the processing, but in the areas B to C, the feedback control based on the signal of the position sensor 12 is not performed, and the profile is obtained. The position of the laser processing head 7 is controlled by performing approximate correction follow-up control based on the data and the proper interval data. Since the section from C to D is an area in which the output of the position sensor 12 is valid, feedback control is performed by comparing the proper interval data with the position sensor output. Then, in the sections D to E, the approximate correction follow-up control is performed again.

[0019]

As described above, according to the present invention, since the position of the machining head is controlled based on the profile data given in advance in the area where the position sensor cannot detect, it is possible to increase the height over the entire length of the workpiece. It is possible to perform accurate laser processing.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a laser processing apparatus to which the present invention is applied.

FIG. 2 is a configuration diagram of a main part of the device of the present invention.

FIG. 3 is an explanatory diagram showing control area divisions.

[Explanation of symbols]

 1 Roll 1a Roll Surface 2 Spindle Bed 3 Moving Table 4 Fixed Bed 5 X-Axis Table 6 Y-Axis Table 7 Laser Machining Head 8 Beam Expander 9 Laser Oscillator 10 Servo Motor 11 Tracking Table 12 Position Sensor 13 A / D Conversion Unit 14 Positioning Unit 15 Servo driver

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukihisa Fukuda 46-59 Nakahara, Tobata-ku, Kitakyushu City Nittetsu Plant Design Co., Ltd.

Claims (1)

[Claims] 1. A spindle bed for rotatably supporting and rotatably driving a shaft of a workpiece, which is a cylindrical body, and a workpiece surface on a table movable along the rotation axis of the workpiece. It has a laser processing head mounted so as to be able to come in contact with and separate from it, and a position sensor for detecting the position of the surface to be processed, and the distance between the laser processing head and the surface to be processed maintains a predetermined value. Is a control method of a laser processing apparatus for continuously performing laser processing in the circumferential direction and the axial direction on the surface to be processed while controlling based on the signal of the position sensor, wherein the position sensor detects After adjusting the distance between the laser processing head and the surface to be processed in an impossible area, after setting the proper distance of the laser processing head to the surface to be processed in the area where the position sensor can detect. , Remember in advance Control method for a laser machining apparatus which is characterized in that in accordance with profile data of the workpiece are.