KR20030043779A - Welding apparatus and method using laser beam - Google Patents

Abstract

PURPOSE: A laser beam welding device and a method thereof are provided to weld easily by generating symmetrical welding beads perfectly with using a laser beam without adjusting the welding line through a microscope by a worker or automatic seam tracking. CONSTITUTION: A laser beam welding device comprises a gas supply unit; a laser beam generator(20) generating laser beam; a reflector reflecting the laser to the object to be welded and vibrating at high speed; a focus lens(40) focalizing the laser from the reflector on the object; a display unit photographing and displaying welding the object by the focused laser beam; a computer(66) controlling components; and a moving unit transferring the welded object. The laser beam welding device welds the inside and the outside of welded metal bellows by welding metal sheets symmetrically and perfectly with using continuous wave or pulse type laser beam.

Description

Welding apparatus and method using laser beam

TECHNICAL FIELD The present invention relates to a laser beam welding apparatus and method, and more particularly, to generate a perfect symmetric weld bead using a laser beam, to deepen the depth of penetration, and to manually manipulate the weld line through a microscope, It enables welding without the need of automatic seam tracking, which requires automatic search, no delicate alignment or maintenance, and is not sensitive to minute vibrations or temperature differences so that anyone can easily weld. A laser beam welding apparatus and method.

In general, the production of welded metal bellows is widely used throughout the industry, including missile fuel injection equipment, aircraft, semiconductor production equipment, high pressure and high temperature chemical refinery processes, vacuum valves, and mechanical seals. It was a labor-intensive industry that was only possible by skilled personnel.

The welded metal bellows is a flexible metal corrugated plate made by forming a circular female and male disk by diaphragm stamping by bending and cutting a thin metal sheet of about 0.1 mm and overlapping them to weld inner and outer diameters. Make

Tungsten inert gas (TIG: Tungsten-Inert-Gas), plasma, electron beam, MIG, GTAW, etc. are used as heat sources that are conventionally used for micro fusion. Among them, TIG welding torch is most used.

This conventional welding method overlaps female and male diaphragms, inserts a cooling ring between them, welds the inner diameter to create a single convolution, and then stitches them to rotate, and the outer diameter. During welding, the operator must keep the distance between the welding torch tip and the welding part constant through the microscope while welding is in progress, and also to control the welding line to follow exactly, After welding welding, it's a difficult task that requires a fairly skilled skill to move on to the next one and continue the task.

As described above, the conventional welding method has a low welding speed, severe thermal damage to the welded part, high fatigue of the operator, and quality of the product is determined according to the skill of the welder, thereby making it difficult to maintain uniformity of quality. In addition, the automation of the process is very difficult, the welding speed is also about 10-12 inches per minute in the case of 0.2mm thick material with two sheets of thin plate, 60 minutes 4 inch diameter welding takes about one hour, Unskilled workers need more time.

During the welding process, the operator must keep track of the welding line through the microscope at all times, and argon, which is a welding gas to prevent oxidation, flows into the welding area during the welding process, which causes a health problem of oxygen deficiency for the worker. There is a problem.

In the past few years, laser bellows welding has been attempted between laser producers and bellows producers, but they are still in primitive or limited production. I have a problem. For example, no matter how precisely a tool such as an arbor or a clamp for welding is produced, due to the accumulation of mechanical errors, the welding line has to move from side to side or back and forth, and special sensors and devices are used to track them. Even though a perfect automatic seam tracking system is achieved by using, the critical problem of asymmetry is that the weld bead is not exactly positioned at the center of the material due to the characteristics of the laser.

One of the advantages of using a laser for this particular welding is the extremely small size of the laser beam and the high density of integrated energy. Focused laser beams have a diameter of about 0.1-0.2 mm and a power density of about 3-4 Mwatt / cm ² , which generates energy that is so high that it is incomparable to the TIG method. By enabling the melting, the welding speed can be about 10 times faster than the TIG, and the life is greatly improved due to the deep penetration and less heat damage around the welding. However, due to the characteristics of the laser beam, it is thought that the center of the beam should have the highest energy, but in practice, the hot spot moves its position at all times according to the change of optical component or output power. Therefore, even if the laser beam is always scanned in the center of the two objects to be welded, the actual melting of the right and left biased problem, which brings a critical problem to the quality of the product.

US Pat. No. 6.040,550 introduces a device which automatically finds a welding line through a special vision sensor and an optical device, and constantly irradiates a laser beam at the center of the moving welding line. Problems occur easily due to temperature change or RFI (Radio Frequency Interference) generated from the laser system, which makes alignment misaligned, device design and maintenance difficult, and asymmetric welding beads mentioned above. .

In addition, in US Patent No. 6,078,021, a welding method using a laser beam and an electron beam has been introduced. When the beam is tilted and irradiated only in one corner direction of the welded part, there is a problem in that the symmetrical beads are not formed and thus the quality is deteriorated. , U.S. Patent Nos. 5,478,983 and 5,410,123 describe an inner diameter and an outer diameter welding using a rectangular beam, but there is a problem that a problem may occur due to one-way irradiation.

Accordingly, the present invention has been made to solve the above problems, the present invention uses a laser beam to create a perfectly symmetrical weld bead, deep penetration depth, the operator to manually control the welding line through a microscope, or automatically Lasers enable welding without the need for automatic seam tracking, no delicate alignment or maintenance, and no sensitivity to minute vibrations or temperature differences, making lasers easy to weld It is an object of the present invention to provide a beam welding apparatus and method.

1 is a block diagram showing an outer diameter welding device constituting the laser beam welding device of the present invention.

Figure 2 is a block diagram showing an inner diameter welding device constituting the laser beam welding device of the present invention.

3 is an explanatory view showing a laser beam irradiation process and principle according to the present invention.

Figure 4 is a schematic view showing an inner diameter welding clamp fixture according to the present invention.

5A and 5B are explanatory diagrams showing a laser beam irradiation method of outer diameter welding according to the present invention;

6A and 6B are explanatory diagrams showing a laser beam irradiation method of inner diameter welding according to the present invention;

7A and 7B are diagrams each showing a welding form according to the prior art and a welding form according to the present invention.

8 is a block diagram showing a thin plate supply apparatus for inner diameter welding according to the present invention.

Figure 9a is a block diagram showing a welding ring according to the present invention.

FIG. 9B is a sectional view taken along the line A-A of FIG. 9A; FIG.

10A and 10B are configuration diagrams showing an incorrect alignment state of the male and female diaphragms.

11 is a block diagram showing the formation of a weld bead according to the present invention.

12 is an explanatory view schematically showing an outer diameter welding method according to the present invention.

* Description of the symbols for the main parts of the drawings *

19: laser energy supply 20: laser beam generator

21: upper laser beam 21a: position shift laser beam

22: lower laser beam 23: spectroscopic lens

25: upper slide table 26: lower linear slide table

31: stepper motor 32: robot arm

33: vacuum cup 35: head crank

36: air cylinder 38: reflector

39: welding nozzle 40: focusing lens

41: Water Lamination 42: Arm Lamination

43: upper bite turn plate 44: lower bite turn plate

46: focusing lens 49: monitor

56: DC motor 58: solenoid valve

62: welding ring 66: host computer

92: upper container 93: side container

According to the present invention for achieving the above object, a gas supply means; A laser beam generator for generating a laser; A reflector reflecting the laser to a welding object and capable of vibrating at high speed; A focus lens for focusing the laser from the reflector to the welding object; Display means for photographing and displaying a state in which the laser focused by the focus lens welds a welding object; A computer controlling each of the components; And it provides a laser beam welding apparatus comprising a moving means for moving the welding object is completed welding.

In addition, the present invention comprises the steps of reflecting the laser beam at a predetermined angle to the reflector; And when the reflector is stopped and not stopped, the laser beam is reflected at the center of the reflector at a 45 degree angle to pass through the center of the focus lens to pass through the welding nozzle to reach the welding site. do.

In addition, the present invention comprises the steps of reflecting the laser beam to the plurality of reflectors at a predetermined angle; And reflecting the laser beam at high speed while scanning the laser beam in the form of a line, and when the reflector is stopped, adjusting the laser beam to be positioned at an edge of the welded portion.

The present invention relates to a laser beam welding apparatus and method including an inner diameter welding device for welding an inner diameter and an outer diameter welding device for welding an outer diameter, and welding a metal bellows using a laser.

In addition, in the present invention, both the inner diameter welding and the outer diameter welding scan the laser beam at a constant width and in the form of a line instead of the beam at a point falling at a speed of 2-4 KHz, thereby simultaneously distributing the hot spots of the laser beam on the welded portion. Even if the welding line moves to the left or right, the welding proceeds smoothly when it enters the scanning line.

In the case of the inner diameter welding, the laser beam is divided into two and scanned at a 45 degree angle, respectively, and synthesized at the welded portion so that the energy from the welded portion is scanned on the side of the welded portion, and the outer diameter welding can be used in the same way. In this case, the laser beam is irradiated perpendicularly to the welded portion without dividing the laser beam, and the energy of the laser beam is reflected on the edge wall of the 45 degree angle of the surrounding welding ring and is scanned on the side of the welded portion.

The present invention has the advantage that the melting proceeds quickly and effectively by welding the side surfaces at the same time, rather than the melting proceeds only in the upper portion of the welding line to achieve the desired penetration depth during welding, the penetration is deep.

The present invention reduces problems such as contamination of personnel and parts by automating loading / unloading of parts.

In addition, the present invention, the inner diameter welding is preceded in the state of overlapping the male and female thin plate, the female thin plate is placed on the inside of the rotary bite lower plate, when the male thin plate is inverted and placed on it, the rotary bite plate to the force of the compressed air Come down by and ask for two overlapping laminations.

The rotary chuck starts to rotate at a desired constant speed by a DC motor, and the inner diameter welding device uses a spectroscopic prism to split the laser beam into two parts of 50:50. Each spectroscopic laser beam passes through the prism, scanning mirror and focusing lens to the welding area, and the two upper and lower reflectors mounted on the resonant scanner shake the laser beam in the form of a line in the form of a line. When the vacuum scanner is stopped, the laser beam is adjusted to be positioned at the edge of the welded part. While the welding is performed, the two reflectors are shaken at high speed, which causes the laser beam scanned by the welding line to cross over the welding line at a high speed to be scanned in the form of a line.

Further, in the present invention, after the scanning line is reflected by the surface of the reflector and passes through the focus lens, the focus is reached, and when the reflector is rotated and moved by an angle of θ1, the reflected beam moves by θ2, and the angular movement at this time The angle has a ratio of 2 θ1 = θ2. At this time, the scan point readjusted by the rotation angle of the reflector has a certain distance from the position before the movement, and if the reflector rotates in the opposite direction and moves by -θ1, the movement distance is also equal to the movement distance at the first half-wave rotation. If such shaking is continued at a high speed, the laser beam to be scanned is represented in the form of lines instead of one point.

When using this scanning method, the energy is distributed evenly on the scanning line, which can solve the problem of asymmetric welding bead that appears as the hot spot of the laser beam is constantly changing, and there is no problem in welding even if the welding line moves slightly due to the width of the scanning line. The conventional manual welding method, which requires manual observation through a microscope and traces the welding line, or expensive automatic welding line tracking device, is also unnecessary, and the melting is quick and effective by reflecting the beam off the welding line to the side of the welding part. Has the advantage.

This scanning method can be applied to the inner diameter and the outer diameter differently. Especially, in the case of outer diameter welding, even if the laser beam is scanned perpendicularly to the welding line, the welding chiller is inserted according to the design of the weld chill ring inserted during the outer diameter welding. The laser beam can have the same effect by the 45 degree edge of the ring.

The present invention has developed a technique for welding metal bellows using a laser, in which melting occurs evenly on the welded portion using an oscillating beam technique. This allows the welding area to be perfectly symmetric in the center of the two materials without being biased in one direction, and reflects the beam that is scanned out of the welding area to be scanned on the left and right sides of the object to enable faster and more complete melting. It is a laser beam welding apparatus and method that enables the production of fast and perfect edge welded bellows without the tracking of welding seams.

The present invention includes the design of inner and outer diameter welding devices and weld rings and sheet feeders.

Types of lasers used as heat sources include Nd: YAG, Nd: Glass, Nd: YNO, CO, CO2, Cr: Ruby, Diod Lasers, Diode Pumped Lasers, etc. Both CW (pulsed operation) and pulsed operation are available.

According to the laser beam welding method and apparatus of the present invention, it can be used to weld a metal thin plate. The present invention may use a laser such as Nd: YAG, CO 2 or a diode laser. In addition, the laser may be a continuous wave (CW) or pulsed (plused type). The present invention provides for expensive seam tracking or line following to compensate for other consequences of moving parts, such as tooling tolerances, stamping tolerances and rotation under welding means. ) Can reduce or eliminate the need. The present invention enables high quality symmetrical welding on sheet materials and reduces the attention required by the operator. The method can also be applied to other materials. Because of the nature of the beam distribution system, the spatial shape of the laser beam does not significantly affect the weld quality of the finished product. The invention can be applied to weld the inner and outer diameters of a welded metal bellows.

The above and other objects, features and advantages of the present invention can be more clearly understood from the following detailed description with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 1 to 12.

In the drawing, reference numeral 19 denotes a laser power supply, 20 a laser beam generator, 21 an upper laser beam, 21a a displacement laser beam, 22 is the lower laserbeam, 23 is the beam splitter, 24 is the beam bending prism, 25 is the upper linear slide table, and 26 is the lower linear slide table, 31 stepper motor, 32 robot arm, 33 vacuum cup, 35 hand crank for manual seam tracking and positioning, 36 is an air cylinder, 38 is a mirror of the scanner, 38a is a displaced scanner mirror, 39 is a welding gas nozzle, 40 is a focusing lens, 41 is a male Male diaphragm, 42 is female diaphragm, 43 is upper bite swivel plate Upper clamp ring, 44 is the lower clamp ring, 46 is the focusing lens, 49 is the CCTV monitor, 50 is the camera, 54 is the threaded shaft, 56 DC motor, 58 solenoid valve, 59 controller, 62 weld ring, 66 host computer, 71, 71a focus, 72 focal plane, 91 is the Bellows diaphragm stack, 92 is the top of the container, 93 is the container side, 94 is the diaphragm stack height adjusting screw, 95 is the diaphragm Diaphragm moving platform, 96 height adjustment nut, 97 reduction gear, 98 motor mounting platform, 99 lower seal plate, 101 is the worktable lower surface, 102 is the soup Spring retainer clip, 103 is a retainer bracket, 104 is a diaphragm platform spacer block, 105 is a DC motor, 106 is a lower mounting platform, and 107 is a guide Guide bearing, 108 is an upper screw bearing, 109 is a lower screw bearing.

1 is a block diagram showing an outer diameter welding device constituting the laser beam welding apparatus of the present invention, Figure 2 is a block diagram showing an inner diameter welding device constituting the laser beam welding device of the present invention, Figure 3 It is explanatory drawing which shows the process and principle of the irradiation of the laser beam which concerns on this invention. Figure 4 is a schematic view showing an inner diameter welding clamp fixture according to the present invention, Figures 5a and 5b is an explanatory view showing a laser beam irradiation method of the outer diameter welding according to the present invention, Figures 6a and 6b It is explanatory drawing which shows the laser beam irradiation method of the inner diameter welding which concerns on this invention. Figures 7a and 7b is a configuration diagram showing a welding form according to the prior art and the welding form according to the present invention, respectively, Figure 8 is a block diagram showing a thin plate supply apparatus for inner diameter welding according to the present invention, Figure 9a It is a block diagram showing the welding ring according to the invention. FIG. 9B is a cross-sectional view taken along the line A-A of FIG. 9A, and FIGS. 10A and 10B are configuration diagrams showing an incorrect alignment state of the male and female diaphragms, and FIG. 11 is a configuration diagram showing formation of a welding bead according to the present invention. 12 is an explanatory view schematically showing an outer diameter welding method according to the present invention.

1 shows a configuration of an outer diameter welding device constituting a laser beam welding device according to the present invention.

The laser beam 21 is reflected at a predetermined angle on the reflecting mirror 43 of the resonance scanner. In the state in which the reflector 43 is not shaken and is stopped, the laser beam is reflected at the center of the reflector at a 45 degree angle, passes through the center of the focus lens 40, and passes through the welding nozzle 44 (see FIG. 4) to reach the welding site. do.

In a more specific configuration of the outer diameter welding apparatus, there is a resonant scanner equipped with a reflector at the end of the laser oscillator, that is, a reflector 43, which is turned down by 90 degrees by the reflector 43, and passes through the center of the focus lens 40. By passing through the center of the gas nozzle it is in contact with the welding line. The CCTV camera 50 is mounted so as to pass through the focus lens 40 and to enlarge the welded portion so that the image can be viewed on the TV monitor 49 to facilitate initial position selection and focal length control.

The welding gas nozzle for preventing oxidation forms a narrow gap between the welding part and the nozzle, and the gas flows and fills therebetween, thereby enabling an effective shield. It is designed to work with 10-15% of the conventional TIG flow in one direction. In addition, the nozzle 39 can be easily moved up and down including the focus lens 40 to easily control the focal length while watching the CCTV monitor 49.

2 shows the configuration of the inner diameter welding apparatus.

The laser beam 20 is split in two at 50:50 by the spectroscopic lens 23, and the two split beams 21 and 22 are irradiated up and down toward the welding site.

The laser beam 21 is bent by 90 degrees by the prism 24 and irradiated in parallel with the other beam 21, and the beam is not shaken while the two reflectors 38 and 39 of the resonant scanner are not shaken. Passes through the center of the focus lens 40, 46 to be formed at the edge of the welding portion.

The two split beams are synthesized at the welding site, and the rotary chuck which is operated by the rock-axis air during the welding process is rotated by pressing the two female and watermelon plates 41 and 42 at an appropriate pressure, and the laser is fired. The edges of the two sheets are melted together by the beam and welded together.

As shown in FIG. 2, conventional manual welding, such as TIG, or any other type of welding, is usually performed internally.

When the female thin plate 42 is placed on the inside of the rotating bite lower plate and the male thin plate 41 is turned upside down and placed thereon, the rotating bite plate is lowered by the force of the compressed air to bite the two overlapping thin plate plates and rotates. The holder plate starts to rotate at the desired constant speed by the DC motor 34.

The inner diameter welding device uses a split laser beam splitter 23 to split the laser beam into 50:50 bifurcations, each of which is equipped with a prism 24 and a scanning mirror 38. 39 and through the focus lens 40, 46 to reach the welding site.

The two upper and lower reflectors 38 and 39 mounted on the resonant scanner scan the welding beam in the form of a line while shaking at a fixed frequency.

The laser used in the inner diameter welding apparatus may be used as long as the laser generates enough energy to melt the material. The inside of the device is designed to block the air, and inside it is composed of optics for the laser beam, clamping fixture, robot arm for inserting the welded parts and picked up convolution. It also includes CCTV, computer, etc. to watch the progress.

There are several requirements for the laser system used, for example, energy, shutter, interlock, etc. must be computer controlled and the material melted as mentioned above. Lasers with sufficient energy below can be used, for example Nd: YAG, Nd: Glass, Nd: YVO, CO, CO 2, Cr: Ruby, Diod, Diod Pumped, and the like.

By sealing the inside of the inner diameter welding apparatus, it is possible to protect various optical devices, such as lenses, reflectors, prisms, spectroscopic lenses, and laser rods from contamination such as dust. In addition, by removing the oxygen inside and injecting a welding gas (argon) to prevent oxidation during welding, by keeping the pressure inside the sealed weld higher than the atmosphere to prevent the introduction of external oxygen or contaminants, This eliminates the need for a clean room of class 1000, the environment required for bellows welding.

As the welding work is performed in the enclosed space, the safety of the operator is guaranteed from the laser beam, and the work of the parts is performed by the robot arm instead of the operator, thereby reducing the error or contamination of the worker. Compared to the conventional method of constantly flowing oxidation welding gas, it is not necessary to use any gas other than the gas injected into the closed space during welding, and it is possible to reuse the gas collected through the filter after welding. Brings savings.

In terms of worker safety, it also greatly helps prevent accidents caused by oxygen inhalation due to inhalation of gas such as argon.

Opening and closing of the rotary plate holding the thin plate is performed by an air cylinder operated by compressed air, and the pressure of the rotating plate is controlled by the applied air pressure.

The robot arm which inserts a thin plate by the rotary stage controlled by a stepper motor, and picks up after welding is precisely controlled. These three robotic arms are equipped with suckers at their ends and are operated by a vacuum pump, which is precisely operated by a computer and is connected to a vacuum pump and a vacuum storage tank connected thereto.

FIG. 3 shows the shape of a beam that is scanned onto the weld line while the laser beam is reciprocating by the reflector. The scanning line indicated by the solid line 21 in the figure is reflected by the surface 38 of the reflector, passes through the focus lens 40 and reaches the focal plane 72, and the reflector 38 is rotated so that the? The reflecting mirror 38a moved by an angle moves the reflected beam by θ2, and each moving angle at this time has a ratio of 2θ1 = θ2 _.

At this time, the scan point 71a, which is re-controlled by the rotation angle of the reflector, has a certain distance from the position 71 before the movement, and when the reflector rotates in reverse and moves by -θ1, the movement distance is also rotated by half wavelength first. It will be equal to the distance traveled.

If such vibration is continued at high speed, the laser beam to be scanned appears in the form of a line rather than a point.

When using this type of scanning method, energy is distributed evenly on the scanning line, so that hot spots of the laser beam are constantly changed, and the width of the scanning line can be solved. Even if this movement is not a problem, there is no problem in welding, and it compensates the conventional disadvantage of manually observing the microscope and traces the weld line, and it is not necessary to have an expensive automatic weld line tracking device and melts by reflecting the beam off the weld line to the side of the welded part. This is fast, effective and deep penetration.

3 shows an example of a method of irradiation while shaking. The laser beam 21 is reflected on the surface of the reflector 38 which is moved by the controlled tilt angle while the shaking of the reflector is stopped, and the angle of the reflector is moved by moving the angle of the reflector while the reflector 38 is stopped. The beam passes through the center of the focus lens 40 to steer the focus 71 to the weld line 72.

By moving θ1 from the center to one side by half 38a of the overall angle of movement of the steered reflector 38, the laser beam 21a passing through the focus lens moves at an angle of θ1 from the center.

Therefore, the laser beam irradiated on the focal length also moves a certain distance from the center, and when the reflector 38 moves by θ1 from the center, the same phenomenon occurs on the opposite side, and the irradiated beam appears in the form of a line rather than a point. The area of the linear shape to be irradiated can be changed by adjusting the angle of movement of the reflectors 38 and 39.

Figure 4 shows the configuration of the upper and lower rotation plate used for inner diameter welding.

As shown in FIG. 4, the upper and lower rotary chucks on which the curved plates of the female and male are placed are formed to have surfaces having the same shape as the curved plates of the thin plates. The reason for this bend is to make the sheet automatically centered.

As such, the robot arm's ability to position the thin plate on the rotary bleeding pin helps to reduce the required precision, and the processing tolerance of the technology currently in use is +/- 0.01mm. In that case, the tolerance is about 0.1 mm is sufficient.

5 shows the shape of the welding line and the shape of the laser beam irradiated in the case of the outer diameter welding apparatus. The beam which is irradiated to the welding line through the focus lens by the floating reflector 28 descends to a parallel line and is irradiated perpendicularly to the welding line, and the laser beam irradiated to the welding line is irradiated in the form of a line because the speed of the floating reflector is very high. The width of the radiation can be controlled to the maximum angle of the resonant scanner, which is usually 2-3 times the width of the weld, eliminating the need for expensive equipment to track the welding seam during welding.

The floating speed of the reflector can also be changed by manipulating the frequency of the resonant scanner, and since the focal length laser beam can shake 4000 times per second, the overlapping of the beam passing through the welding line is sufficient, so there is no problem in welding.

Such a scanning method can be applied to the inner diameter and the outer diameter in the same manner, and in particular, in the case of outer diameter welding, as shown in FIG. 5, a weld chill ring inserted during outer diameter welding even when the laser beam is vertically scanned on the welding line. Depending on the design of), the laser beam outside the weld line can have the same effect by the 45 ^o edge of the ring (see FIGS. 6A and 6B).

As shown in FIG. 6A, the laser beam is manipulated to be positioned at the edge of the welded part when the resonance scanner is stopped. While the welding is performed, the two reflectors 38 and 39 vibrate at a high speed. As a result, the laser beam scanned by the welding line crosses the welding line and returns to the high speed to produce the effect of scanning in the form of a line. Indicates.

6A and 6B show the shape of the laser beam applied to the welded portion in the case of inner diameter welding. In the initial operation, as shown in FIG. 6A, the reflector is fixed at the center of the shake while the shaking of the reflector is stopped. At this time, the beam passing through the focus lens is controlled at the edge of the welded portion. The sufficient overlap of the laser beam irradiated by the floating reflector allows for complete melting.

7A and 7B show the welding contents of the conventional TIG method and the laser method in a cross section of the welded portion. As a result of the magnification analysis, the laser welding contents show that the penetration is much deeper, which means that the welding strength is higher. In addition, laser welding is much lighter than the conventional method because of the heat-affected zone (HAZ: Heat Affected Zone) generated due to prolonged heat. Proven by stress analysis and life cycle test.

As shown in FIG. 9, a semi-circular ring that can be reused is sandwiched between two sheets 54 of inner diameter welded, and when the welding starts, the laser beam is irradiated along the rotating welded portion. While shaking, the laser beam repeats the welding area.

0.1 mm thick thin plates, which have been decontaminated by washing and drying, are stored in sealed containers separately from females and females, and the containers are fixed in a position where the robot arm can pick up. As shown in Fig. 8, each container is composed of a sensor that automatically reads the presence or absence of a thin plate and the position of the top, and a device for constantly pushing up the position of the top.

It is equipped with a 40-100 magnification CCTV camera to precisely move the initial reflector so that the laser beam can be precisely positioned at the edge of the weld line. In addition, the welding can be observed by the camera located above and below, respectively. By using special optics, the welding part passing through the focus lens can be observed while welding is in progress. The magnified image is displayed on the TV monitor, making it easy to control the focusing distance of the focus lens during the initial control of the reflector. do.

The computer responsible for the overall control of the device is responsible for the speed of each device's switch or motor, the opening and closing of the laser and energy control, and the status of each part. In the case of inner diameter welding, check whether there are any parts left in the container where each part is mounted, whether the welding is finished and the clamp is raised, and turn the robot arm by 90 degrees. Place it on the container, lower the arm again, open all three sucker suction switches, lift the arm up again, rotate it 90 degrees further, and drop the welded parts and the female diaphragm. After that, raise the arm again, rotate 90 degrees further, lower the arm, drop the male diaphragm, raise the arm, rotate the position by -270 degrees, and so on.The welded boom comes out and the material to be welded is located. Lower the upper clamp to start the rotation while pressing the female and female diaphragms, open the shield gas switch to flow the gas, and then turn on the laser for the correct time to perform welding. Work is controlled by the computer, and the operator's name, work start time, work content (part name, number of work, etc.) are recorded.

The outer diameter welding device is also controlled by the same computer and checks the laser's coolant circulation, temperature, and emergency switch during operation.

Manual control of the computer may also be used for final control of each part of the device. Opening time of inner diameter welding such as opening / closing, rotation speed, laser on / off, robot arm movement, etc. depends on the diameter of the sheet, but it is usually available every 10-30 seconds.

This is because welding speeds are available at speeds of 40-120 inches / minute per second, depending on material and thickness. The welding speed can be about 10 times faster than conventional TIG with maximum welding speed of 12 inches / minute.

The outer diameter welding apparatus includes a laser oscillator, a resonant scanner, various optical instruments, a gas nozzle, a CCTV camera, a lathe for returning parts and a DC motor, and a linear table for moving to the next position. The inner diameter welded convolutions are collected and screwed into the arbor and fixed by the arbor.

In the same way as the inner diameter welding apparatus, any type of laser capable of melting the material can be used, and it is also designed to be controlled by a computer, such as energy, shutter, and interlock.

A linear motion table is used to move the latch located at the top to the next weld line in an automatic or manual manner by the desired distance. In case of manual operation, the handle can be rotated while viewing the magnified image of the CCTV monitor 49, and in case of automatic operation, the accurate movement distance can be controlled by a stepper motor and a computer.

In the case of outer diameter welding, a half weld ring is inserted to absorb heat generated during welding and to accurately control the amount of melting. As shown in Fig. 9, in the specific design of the welding ring, first, it is possible to reuse it as two semicircles, the edge of the ring is chamfered at an angle of 45 degrees, and the surface of the edge is processed finely so that the laser beam This can be reflected.

Therefore, as shown in FIG. 5B during the welding, the scanning line deviating from the welding line is reflected at the edge of the ring and applied to the side of the welding portion.

As such, the problem of one-way irradiation was supplemented by dividing the laser beam in two directions in the inner diameter welding, and in the case of the inner diameter and the outer diameter welding, the reflecting beam was dropped in the form of a line, so that the effect of the rectangular beam was much better than that of the rectangular beam. Have As a result, in the case of inner diameter welding, an optical device for irradiating a laser beam must be included in the inner diameter, so that the optical equipment can be relatively far from the welding area, and thus the life is long. Even small parts can be welded. As the optics are installed far apart, even if the size of the support plate is changed, it is very easy to replace the swivel plate and re-control the optics.

In this case, the size and symmetry of the weld bead can be easily controlled by the position of the two beams, and the irradiation lines out of the weld area are reflected on the wall surface of the rotary chuck, which is applied to the side of the weld zone, and the penetration is deep. .

Without the weldability tracking device, the laser beam should be dropped to completely cover the thickness of the material and the part where the weld line moves left and right due to the accumulation of machining tolerances. The width of the scan line is determined by the floating angle, and in general, it is controlled to move about 3-4 times the thickness of the welding material. By irradiating the laser beam in this manner, it is possible to process an object wider than the diameter of the laser beam, and it is possible to reliably weld even if the seam is slightly different in height and width.

5A and 5B and 6A and 6B, it can be seen that a scan line is applied to the welded portion during the inner and outer diameter welding. In addition, as shown in FIG. 10, in the case where two sheets of thin plates are not standing side by side, the welding content is not very good when the beam is not shaken and is scanned at the center of the two sheets by the welding line tracking device. You can expect results.

In the case of a normal high power laser, the density of the energy moves constantly when looking at the cross section of the laser beam being fired. As the welding progresses, it is easy to see that slight energy changes and energy density distributions change accordingly. As such, the energy density distribution that changes frequently during welding is because the size of the laser beam is similar to that of the welded portion, so that when the high energy density is biased to the left and right, more melting occurs therein, and therefore the welding result is uneven or irregular. In some cases, the welding is not performed, and the so-called asymmetric problem, which is biased to one side, occurs seriously. In the method of shaking irradiation, the energy density is uniform throughout the irradiation line, and the energy density change according to the energy change is also It does not affect the even density distribution of the entire radiation line. Therefore, the manufacturing tolerances of each device is not a problem even if the processing tolerances are not very precise, and the skill of the operator also does not significantly affect the production quality.

It is also easy to replace the rotating rotary plate and to recalibrate the optics in case of replacing the work with the thin plate of different size. Both floating reflectors and beam delivery optics are fixed on the translation stage, and if you replace them with a new job, you can easily change the position of each optic by changing its position.

The positional tolerance of the laser beam used in the present invention is +/- 0.01 inch, which is much easier than the positional tolerance +/- 0.001 inch of the device for precisely positioning the beam in the middle of two sheets using a weld line tracking device. This is a revolutionary invention that can perform welding perfectly without requiring high precision, which requires no skilled workers, easy work replacement, easy melting, resulting in deep penetration and long product life. Easy to maintain This welding content can be seen by comparing the conventional TIG welding content (see FIG. 7A), which is a conventional low density heat source, with the welding content (see FIG. 7B) of the present invention.

The inner diameter welding device of the present invention is very easy for initial control and alignment when replacing from one bellows operation to another sized operation. Pressing and unloading the upper and lower bleeding rotary plates 43 and 44 (see Fig. 4) for about 10-15 minutes from the bearing without special tools, and moving the previous stage carrying the upper and lower optics, the new laser beam Two tasks are manipulated to illuminate the edges of the sheet, making it easy to finish.

Each of the bite rotary plate 43, 44 has a shape such as bending of the thin plate so that the thin plate is positioned at the correct position. In addition, the inner wall diameter of the lower bleeding rotary plate is the same as the outer diameter of the thin plate, so if the thin plate brought by the robot arm is dropped here, it will be positioned in the correct position.

The material of the part that bites the thin plate of the swivel plate prevents excessive overheating by using the material with high thermal conductivity to prevent thermal damage of the thin plate and contributes to the improvement of product quality.

The thin plates before washing and drying are stored in a closed container, which is fixed to the female and water plate pickup positions under the robot arm of the inner diameter welder. This container 93 has several functions. Each male and female is stored in a different container, and is easily fixed by a spring clip 102. The clip is fixed to seal the thin plate container again under the sealed inner diameter weld table, and inside the inner diameter weld part. The operation of removing oxygen and injecting the welding gas is simultaneously performed inside the vessel. The sheet is 0.001 inches thick and 1000 sheets stacked, but only four inches tall. Three vessels for receiving the male, male and welded convection lines are fixed under the table, and inside the thin vessel, there is a screw 94 operated by a motor to push up the bottom plate 95, which is dedicated to the thin plate 91. Role.

This function ensures that the robot arm can suck up the sheet without problems by ensuring that the top of the stored sheet is always pushed to the desired position. Push up the thickness, and prepare for the next task. After the last sheet is lifted, the sensor will signal the computer to notify it and the work will be completed. One container will store more than four hours of work.

The three robot arms simultaneously lift the arm and the watermelon and the welded convex line at each 90 degree angle and rotate it 90 degrees so that the welded convex line is placed in the third container and the arm thin plate is in the rotary squeeze plate. Rotate the plate 90 degrees further and place the watermelon and rotate it -270 degrees so that the robot arm is out of the weld zone.

In the case of the outer diameter welding device, the CCTV camera 50 is installed so that the welding line can be enlarged on the monitor and the nozzle including the focus lens is moved up and down to find a clean image on the monitor. It is designed to be easy to control.

The crosshairs in the center of the monitor also indicate the point where the laser is fired and manipulate it to match the weld line. Resonant scanners with floating reflectors are readily available and can be manipulated to change the angle of vibration.

Such a device is equipped with two upper and lower (38, 39) to the inner diameter welding device and one 43 to the outer diameter welding device.

The welding gas is injected into the outer diameter welding device by the welding nozzle 39, which flows out of the small space between the nozzle end and the welding portion located near the welding to block oxygen.

As such, welding gas flows around the laser beam irradiated through the center of the nozzle life, and a small amount of gas can be used by covering the welding portion, and the flowed gas is sucked back into the vacuum and discharged to the outside.

Keep all the information you need for welding in a notebook, enter it into your computer before welding starts, and then re-pilot it to the starting point to find the optimal conditions. Because the results of welding can change due to changes in the microscopic conditions, the previous condition can be a starting point, but not absolutely repeatable information. For example, if the reflective wall of the turning wheel changes in material or the surface discolors due to repeated heat, the bite pressure changes, the temperature and purity of the welding gas, the microscopic changes in the material, the cleaning conditions, etc. Due to the possibility of change, the reconditioning process must be carried out to adjust the optimum conditions.

On the other hand, the outer diameter welding ring used in the present invention has a chamfered shape of a 45 degree angle without using a right angled groove edge (see FIG. 5) or a notch, and the evenness of the surface reflects the laser beam. It should be sufficient.

It is easy to clean, less contaminated, and easier to manufacture than the square groove edge even in repeated use, and the cost is low. The energy reflected at the corners of the 45 degree angle is simultaneously applied to the sides of the weld, which allows for much more efficient and faster melting than the beam being fixed in the center at right angles to the top of the weld. Reflections on the surface of the ring result in less energy absorbed in the ring, resulting in longer ring life, and thus re-use at least 30 times.

Meanwhile, the equation for obtaining the circular region, the triangular region, and the welding service shown in FIG. 11 is as follows.

H * 2t = Aw (1)

H = (3 / 2π * t ² + t ² ) / 2t (2)

H = (3 / 4π + 1/2) t (3)

H = 2.856 t (4)

Hd + 2 ^1/2 * t + t = H (5)

Hd = H-2 ^1/2 * t-t (6)

Hd = 0.441 t (7)

Area of circle

Ac = 2π * t² (8)

Area of triangle

At = t² (9)

Area of pie

Ap = 1/4 Ac-At

= 1 / (2 ^1/2 * t-t) (10)

Welded area (Ac-Ap)

Aw = 2π * t²-1 / 2π * t²+ t² (11)

Here, in FIG. 11, H is the distance from the lowermost periphery of the weld bead to the top of the shim, Hd is the distance from the uppermost periphery of the seam to the top of the shim, and t is from the triangle apex in the weld bead to one end of the shim. Distance.

The laser beam welding apparatus and method of the present invention as described above are as follows.

First, the outer diameter welding device constituting the laser beam welding apparatus of the present invention causes the laser beam to be shaken at high speed by a resonant scanner to scan in the form of a line instead of one point. Therefore, it is possible to use both a method of splitting the laser beam in two, and recomposing them in the weld, and irradiating them vertically without dividing them in two. In addition, by using a CCTV camera to enlarge the weld to view the image on the monitor and use it to control the exact focus distance and position of the laser beam.

Next, in the inner diameter welding apparatus constituting the laser beam welding apparatus of the present invention, a fine thin plate is supplied to the biting rotary plate by the robot arm, and the welded conjugation is also taken out by the robot arm. For this purpose, a stepper motor, rotary table, air cylinder, three robot arms, vacuum cups, high vacuum pump, solenoid air valve switch air velve switch) is used, and has the following advantages.

It is possible to prevent the contamination of the cleaned thin plate, to reduce the problems caused by the operator's error, and the automated device is unnecessary for the worker's full time. In addition, the cost is reduced because no skilled workers are required, and the cleaned thin plates are stored together with the shield gas in a sealed container, and are used by inserting them into the sealed welding part, and the inside of the welding part is filled with shielding gas for preventing oxidation. Unused thin plates are also stored in such closed containers with shielded gas to prevent natural oxidation by oxygen in the air.

Manually separating thin plates from male and female and inserting them into the weld part takes considerable time, and this makes up for the shortcomings of dealing with thin plates while wearing special gloves and worrying about contamination. In addition, by splitting the laser beam into two and re-compositing at the welding part, the optical device can be far away from the welding area to solve the problem that various foreign substances generated during welding contaminate the focus lens or reflector, sufficient space around the welding area Easy maintenance, such as replacement of parts, welding bead control by controlling the upper and lower beams separately. In addition, the energy out of the welded portion of the laser beam irradiated is reflected by the wall surface of the bite rotating plate is applied to the side surface of the welded portion, so that melting is fast and penetration is deep, and the product quality is greatly improved. In addition, by using a CCTV camera, the welded part can be enlarged to view an image on the monitor, and used to control the exact focal length and position of the laser beam. It can be injected in the form, and it is easy to replace the swivel plate to minimize the device control due to the replacement of the work parts.

On the other hand, when the present invention will be described as superior to the conventional welding method as follows.

First, because of the high density of integrated energy by using laser, melting and coagulation are performed in a short time. Therefore, the thermal damage area is less than that of other methods, and the penetration is deep, and the life of the product is long.

Second, skilled workers are unnecessary.

Production cost is reduced by 10 times welding speed than conventional welding methods such as set materials and TIG.

Fourth, labor costs are reduced by the automation of the process.

Fifth, the welding difficulty according to the characteristics of the material is easy to weld.

Sixth, in the case of the inner diameter welding device, the beam is split into two and each is scanned at an angle of 45 degrees from the top and the bottom to be synthesized at the welding site so that the inner diameter of the sheet is not limited.

Seventh, the upper and lower split beams can be moved differently, so when welding thick and thin plates, the beams can be controlled differently for optimal welding.

Eighth, it is common to split a beam into two, but to shake it and recombine it.

Ninth, the expensive weld seam tracking device is extremely fine in performance, so there is a problem even in the small vibration, the present invention is not significantly affected by changes in the surroundings.

Tenth, manual or automatic welding seam tracking device is unnecessary by irradiating the laser beam in the form of a line.

Eleventh, in the case of the inner diameter welding device, the energy of the laser beam, which is scanned in the form of a line while shaking at a 45 degree angle, is reflected by the wall surface of the biting rotating plate and applied to the side of the welding part, so that melting is quick and penetration Deeper product quality is greatly improved.

Secondly, in the case of the outer diameter welding device, the energy of the laser beam scanned in the form of a line while shaking is reflected by the welding ring and applied to the side of the welding part, so that the melting is quick and the penetration is deep, thus improving the product quality. do.

Thirteenth, by giving the same curvature of the thin plate inside the bite rotating plate of the inner diameter welding device can be accurately centered by controlling the position where the thin plate is placed. The inner surface of the swivel plate was smoothed to reflect the laser beam.

Fourteenth, the swivel plate is easy to replace, and the optics of the optics is very easy.

Fifteenth, it is possible to observe the progress of the welding and control of the beam position before welding by installing CCTV camera to enlarge the welding part.

Sixteenth, the inner diameter welding device prevented contamination of the working environment, safety of workers, and significantly reduced gas usage by injecting shielded gas into a sealed space and safely extracting it after welding.

Seventeenth, inner diameter welding is done in a confined space, eliminating the need for a Class 1000 Clean Room.

Eighteenth, in the design of the weld ring, the laser beam can be reflected by giving a smoothly treated surface at an angle of 45 degrees to the edge, resulting in longer ring life, easier cleaning, less contamination , Production becomes simple.

Nineteenth, the design of the ring in two semicircles allows for reuse and ease of injection and ejection, which significantly reduces the preparation of outer diameter welds and has a significant effect on cost savings.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

As described above, according to the laser beam welding apparatus and method of the present invention, a laser beam is used to generate a perfectly symmetrical weld bead, deepen the depth of penetration, the operator manually manipulates the welding line through a microscope, or automatically It enables welding without the need of automatic seam tracking, etc., and does not require delicate alignment or maintenance, and it is not sensitive to minute vibrations or temperature differences so that anyone can easily weld. There is.

Claims (1)

The laser beam can be used to weld circular disks made of thin metal sheets, and the laser beam melts the two flavored materials and drops the beams at appropriate intervals, allowing the welding of materials larger than the laser beam size. Beam device.