JPS6336987A - Detector for butt position and butt gap for butt beam welding - Google Patents

Abstract

PURPOSE:To improve butt welding accuracy by projecting 1st and 2nd luminous fluxes to a butt part, detecting the respective rays of the transmitted light, calculating the output values thereof and determining the butt position and gap amt. CONSTITUTION:The tube material 2 which are pressurized and butted by a pressurizing device 5 are projected with 1 the and 2nd luminous fluxes 13, 14 via two optical fibers 11, 12. Optical fibers 15, 16 are disposed below the materials 2 to be welded so that the luminous fluxes 13, 14 are received therein and are guided to photodetectors 17, 18. The materials 2 carried in the axial direction of a mandrel 1 are projected with the luminous fluxes 13, 14 and the output values in the photodetectors 17, 18 are subtracted and added to determine the butt position and butt gap amt. The continuous butt welding with a beam spot 24 of laser light is carried out in succession thereof. Since the butt position and gap amt. are precisely measurable, the accuracy of the butt welding is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for detecting a butt position and a butt gap for performing butt beam welding by irradiating a laser beam, an electron beam, or the like onto a butt part of a welded material.

[Conventional technology]

A welding device that performs butt welding by focusing a beam such as a laser beam or an electron beam emitted from a beam source using a lens device consisting of an optical lens or an electron lens, and feeding the butt part of the welded material to the beam spot. Are known. In such equipment, since the beam spot i~ is irradiated onto a minute area, a thin bead can be obtained and there are advantages such as less welding distortion, but on the other hand, welding defects may occur due to misalignment between the butt weld and the beam spot. Easy to do.

Therefore, it is desirable to measure the butt position of the welded material in the forward direction of relative movement of the beam spot with the welded material, and to align the beam spot position with the butt position based on the measured value. Unexamined Japanese Patent Publication No. 59-14 using an image sensor as a measurement method
1392), one using a magnetic sensor (Unexamined Japanese Patent Publication No. 1983-1
41391) etc. [Problems to be Solved by the Invention] In the method of measuring the abutment position using the image sensor described above, light is irradiated onto the abutment portion and an image is formed on the light receiving element surface using a lens. , the butt position is measured by the difference in brightness between the part corresponding to the butt part and other parts, but since there is noise due to scattered light, when the material to be welded is thin and the butt gap is small, the butt part Difficult to detect. Another drawback is that the equipment is expensive. On the other hand, with the method using a magnetic sensor, it is difficult to detect the butt gap, and it cannot be used for non-magnetic materials to be welded. Furthermore, it cannot be used when the thickness of the material to be welded becomes thin and magnetic guides are provided above and below the material to be welded in order to eliminate vertical misalignment of the abutting portion. The present invention has been made to solve the above problems, and provides a butt position and butt gap detection device that can reliably detect the butt part even for non-magnetic and thin materials to be welded. It is.

[Means for solving problems]

Two light beams are provided in the vicinity of a predetermined weld line, that is, a butt portion, and at least one light beam has a cross section of a portion related to detection that becomes wider in one direction perpendicular to the weld line; applying two light beams to the abutment part, and detecting the light from the light beams that passed through the abutment gap with two light receiving elements,
By calculating the output values of these light receiving elements, the position of the abutting portion and the abutting gap can be known.

[For production]

To explain the case where two light beams have a cross section that increases in width in opposite directions perpendicular to the welding line, if the butt gap is approximately constant, if the butt part shifts in the - direction, the width will increase in this direction. The output from the wider beam becomes larger, and the output from the other beams becomes smaller. Therefore, by taking these differences, it is possible to obtain an output value that is approximately proportional to the position of deviation including the direction from the reference position. Furthermore, by summing the outputs from both light fluxes, it is possible to obtain an output value that is approximately proportional to the butt gap. Furthermore, if the change in the butt gap cannot be ignored, the exact butt position can be determined by correcting it using the sum of the output values from both light beams. According to the configuration of the present invention, all of the light that enters the light-receiving element is light that has passed through the abutment gap, so there is no noise in the optical part of the device.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. This example is based on the title of the invention [Method and apparatus for manufacturing tubes] (
Applied to the implementation of the invention regarding patent application No. 6l-146734)! A roll-formed tube material 2 fed in a state covering the mandrel 1 is held by a tube holder 3 and fed in the axial direction of the mandrel 1, that is, in the direction of the arrow shown. Since the tube material 2 is held in the tube holder 3 with one end of the abutting portion in contact with the reference surface 4 of the mandrel holder 1, the weld line exists approximately on an extension of the reference surface 4. The tube material 2 that has passed through the reference surface 4 is pressurized by the pressurizing device 5, and the abutting portions are brought into an abutting state. The pressure device 5 is composed of a belt 6, an elastic material 7, and an actuator 8. The belt 6 applies pressure to the tube material 2 by the elastic material 7, and is fed at the same speed as the tube material. The pressure on the tube material 2 can be adjusted by an actuator 8. The direction of the laser beam emitted from the laser oscillation source 9 is changed by a reflection device 10, and then focused by a lens device to form a beam spot 24 on the material to be welded.

The position of the beam spot 24 can be moved in a direction perpendicular to the welding line by the action of the reflection device 10. Light emitted from a light source not shown is an optical fiber 11.1
2, a beam of light 13.
14 and is irradiated. Luminous flux 13 below the material to be welded.
Optical fibers 15.16 are open to receive light from the light receiving elements 17.18, respectively. The displacement sensor 19 irradiates the workpiece with parallel light obliquely, measures the heights on both sides of the butt portion from the position of the reflected light, and monitors whether the amount of discrepancy in the butt is within an allowable range. At the rear of the welding device, an optical fiber 20.21 passes light through the weld seam to check for weld defects. The present embodiment is constructed as described above, and its operation will be explained next.

The luminous flux 13.14 is as shown in Figure 6! ! The Ii plane forms a circle having its center on both sides of the butt gap 25. Incidentally, cross sections 13 and 14 of the light beam shown in FIG. 6 indicate portions related to detection, and are represented by the common portion of the emitted light beam cross section and the light receiving surface. That is, the emitted light beam cross section and the light receiving surface may have the same shape as shown in the figure, or either the emitted light beam cross section or the light receiving surface may be larger than this. Therefore, when the abutting portion is displaced upward in the figure, the amount of transmitted light of the light beam 13 passing through the welding material butt gap 25 and reaching the light receiving surface increases, and the amount of transmitted light of the light beam 14 decreases. At this time, the value obtained by filtering the outputs of the light receiving elements 17 and 18 by the arithmetic circuit becomes large. The reflecting device 10 is driven by the output of the reflecting device driving circuit 23 so as to displace the position of the beam spot 24 from the reference position in proportion to the output value of the arithmetic circuit 22 obtained in this way. The reflector drive circuit 23 is designed to provide an output corresponding to the input from the arithmetic circuit 22 to the reflector with a delay in time for the material to be welded to pass through the distance from the center of the light beam 13, 14 to the beam spot 24. There is.

The amount of transmitted light of the light beams 13, 14 passing through the abutting gap 25 is approximately proportional to the size of the abutting gap. Therefore, the light receiving element 1
7. The outputs of 18 are added by the arithmetic circuit 22, and the actuator 8 is operated via the actuator drive circuit 26 so that a pressure proportional to the added pressure is applied by the pressurizing device 5, so that the butt gap is within a predetermined range. ni&lJ @
can do. FIG. 8 shows a cross section of a portion related to the detection of a luminous flux in another embodiment of the present invention. When such a luminous flux is used, the output value for the amount of transmitted light of the second luminous flux 14' having a constant width is compared. Gaps can be detected. In addition, the output value of the amount of transmitted light of the first luminous flux 13' is
The matching position can be detected by dividing by the output value of the light beam 14'.

FIG. 9 shows a cross section of a portion related to detection of a luminous flux in a third embodiment of the present invention, in which the first luminous flux 13'' and the second luminous flux 14'' have triangular cross sections. In this case, the displacement m of the abutting position is accurately proportional to the difference in output value between the first and second light beams over a wide range.

〔Effect of the invention〕

The present invention detects the butt position and the size of the butt gap by passing light through the butt gap, and there is no noise in the optical system, so it can be used accurately even when the gap is small or the displacement of the butt position is small. It is possible to detect the butt gap and the butt position. Therefore, as shown in the embodiments, the present invention is highly effective when manufacturing thin tubes with a wall thickness of about 0.2 mm using a tube manufacturing apparatus with one type of mandrel and tube holder. It is also possible to control the butt gap to be within 20 μm.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a side view, FIG. 2 is a plan view, and FIGS. 3, 4, and 51 are A-A, BB, and C in FIG. 2, respectively. -C sectional view, FIG. 6 is a partial plan view showing the light flux and the abutment part, FIG. 7 is a block diagram showing the signal flow, and FIG. 8 is a part showing the light flux and the abutment part in another embodiment of the present invention. FIG. 9 is a partial plan view showing a light beam and an abutting portion in a third embodiment of the present invention. 1... Mandrel, 2... Tube material, 3...
Tube holder, 4... Reference surface, 5... Pressure device, 6... Belt, 7... Elastic material, 8... Actuator, 9... Laser oscillation source, 10... Reflection Device,
11... Optical fiber, 12... Optical fiber, 1
3... Luminous flux, 14... Luminous flux, 15... Optical fiber, 16... Optical fiber, 17... Light receiving element, 1
8... Light receiving element, 19... Displacement sensor, 20...
Optical fiber, 21... Optical fiber, 22... Arithmetic circuit, 23... Reflector drive circuit, 24... Beam spot, 25... Butt gap, 26... Actuator drive circuit. Applicant's agent Hiroshi Fujimoto Pre-t Figure 6 Condolences 7 Draft 6 Gardening Figure 9

Claims (1)

[Scope of Claims] 1. In a welding device that performs butt welding by sending a workpiece having a linear butt portion to a beam spot located on an extension of the linear butt portion, first and second light beams are provided. ,
At least one of the light beams is arranged so that the cross-sectional width of the portion related to detection becomes wider in the vicinity of a predetermined weld line in one direction perpendicular to the weld line, and the light beam is aligned with the linear butt. A butt position and butt gap detection device for butt beam welding that measures the butt position and butt gap by irradiating the beam onto the beam, detecting the transmitted light, and calculating the output values. 2. The butt position and butt gap detection device for butt beam welding according to claim 1, which measures the butt position by subtracting the output values of the first and second light receiving elements. 3. The butt position and butt gap detection device for butt beam welding according to claim 1, which measures the butt gap by adding the output values of the first and second light receiving elements.