JPH0442077Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a laser welding machine for butt welding metal strips, and in particular to a laser welding machine that can set optimal welding conditions according to the thickness of the metal strip. It is related to welding machines.

<Conventional technology> Since it is difficult to butt weld special steel strips such as stainless steel strips, high carbon steel strips, and silicon steel strips using MIG welding, TIG welding, and flat butt welding, laser welding has recently been implemented. (See, for example, Japanese Utility Model Application Publication No. 135886/1986).

When performing laser welding, the welding conditions are primarily determined by the plate thickness, unless the type of metal strip to be welded changes. That is, the focal position of the laser beam, the output of the laser beam, the welding speed, and the feed speed of the filler wire are determined by the plate thickness. For example, when the plate thickness is large, if the welding speed is fixed, the laser output and filler wire supply speed are set high, and conversely, when the laser output and filler wire supply speed are fixed, the welding speed is set low. If the plate thickness is small, the above procedure may be reversed. The laser torch may be moved up and down in accordance with the thickness of the metal strip so that the focal position of the laser beam is at or near the surface of the metal strip. Therefore, plate thickness information, which is the basis for determining these welding conditions, is usually obtained from the nominal plate thickness from an upstream computer.

<Problems to be Solved by the Invention> However, there is no guarantee that the above-mentioned nominal plate thickness is equal to the actual plate thickness, and in particular, the tip and tail ends of the metal strip are often off-gauge. In butt welding of metal strips, the leading end and tail end are generally welded, so welding defects often occur.

One possible way to solve these problems is for workers to measure the plate thickness using a plate thickness gauge before welding, but this is less efficient, increases the burden on the workers, and poses safety concerns. I also don't like it.

The present invention has been made in view of the problems of the prior art as described above, and to provide a laser welding machine that does not cause welding defects even if the thickness of the metal strip to be butt welded differs from the nominal thickness. It has been done.

<Means for solving the problem> As a result of intensive study on laser welding of metal strips with different thicknesses, the inventors of the present invention have developed a built-in device that can measure the thickness of the leading metal strip and the trailing metal strip. We have found that the objective can be achieved by using a laser welding machine that has been developed, and based on this knowledge, we have come up with the present invention.

The present invention provides a clamp device for clamping the metal strip, which is composed of a laser torch that moves along the abutting portion of the leading metal strip and the trailing metal strip, an upper clamp, a lower clamp, and a clamp cylinder that raises and lowers the upper clamp. A laser welding machine having a laser torch at the entrance and exit sides, characterized in that the laser welding machine is provided with a measuring means for detecting the lowering position of the clamp cylinder of the clamp device and measuring the plate thickness at the entrance and exit sides. be.

<Function and Examples> The present invention will be explained below based on the drawings.

In FIG. 1, 1 is a trailing strip, 2 is a leading strip, 30 is an entry side clamping device,
40 is an exit side clamp device. Each clamp device 30, 40 consists of an upper clamp 31, 41, a lower clamp 32, 42, and a clamp cylinder 33, 43.
It is designed to clamp 2. Also, 50
is a laser torch, which can be moved along a traveling frame 60 by a traveling motor 51, that is, in the width direction of the metal strips 1 and 2.
Reference numeral 52 denotes a condensing lens section, which is raised and lowered by a condensing lens lifting motor 53 to adjust the focal position. 7
0 is the filler wire supplied to the butt part, and this supply speed is determined by the filler wire supply motor 7.
Controlled by 1. Reference numeral 80 denotes a backing metal device, which is adapted to bring the back bar 81 into contact with the lower surface of the butted metal strip by means of an elevating cylinder 82. 9 and 10 are magnetic scales and clamp cylinders 33 and 4.
Detect the descending position of 3.

Next, the operation of the present invention will be described. First, the leading strip 2 and trailing strip 1 are stopped at predetermined positions. Next, each upper clamp 31, 41 is lowered by the clamp cylinder 33, 43 to clamp these metal strips. At this time, the descending position of the cylinder is detected by magnetic scales 9 and 10, and as shown in FIG.
Here, the plate thicknesses of the input and output strips are calculated from these measured values, and the welding speed, focal position, filler wire feeding speed and laser output are determined, and each motor 51, 53, 71 and laser It is output and set to each control device of the power supply device of the oscillator 12 (not shown).

Next, the back bar 81 is brought into contact with the lower surface of the abutted metal strip by the cylinder 82, and the condenser lens portion 52 is moved by the condenser lens lifting motor 53 to the focal position calculated by the arithmetic controller 11. Go up and down.

The laser torch 50 then moves in the width direction of the strip while emitting a laser beam according to the determined conditions to perform laser welding.

In the above example, a magnetic scale was used to detect the lowered position of the cylinder, but there is no need to be limited to this, and a pulse oscillator, differential transformer, etc. may also be used.

Further, although each setting condition is calculated using an arithmetic controller, each condition according to the plate thickness may be created as a table and manually set by an operator.

<Effects of the invention> According to the invention, the actual plate thickness is used instead of the nominal plate thickness as the plate thickness information for determining welding conditions, which enables optimal laser welding and significantly reduces welding defects. can be reduced to

Furthermore, since the actual plate thickness was determined using the movement of the clamp device, welding time was not increased.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating a laser welding machine according to the present invention, and FIG. 2 is a schematic system diagram illustrating arithmetic control. 1... Trailing strip, 2... Leading strip, 11... Arithmetic controller, 12... Laser oscillator, 30... Entry side clamp device, 40... Output side clamp device, 31, 41... Upper clamp device ,3
2, 42... Lower clamp device, 33, 43... Clamp cylinder, 50... Laser torch, 51...
...Traveling motor, 52... Condensing lens section, 53...
Condensing lens lifting motor, 60... Traveling frame,
70... Filler wire, 71... Filler wire supply motor, 80... Backing metal device, 81...
Back bar, 82... Lifting cylinder, 9, 10...
...Magnetic scale.

Claims (1)

[Scope of utility model registration request] a laser torch that moves along an abutment between a leading metal strip and a trailing metal strip;
In a laser welding machine having a clamping device for clamping the strip, which is composed of an upper clamp, a lower clamp, and a clamp cylinder for raising and lowering the upper clamp, at the entrance and exit sides of the laser torch, the lowering position of the clamp cylinder of the clamping device is detected. A laser welding machine characterized by being equipped with a measuring means for measuring the thickness of the metal strip on the input and output sides.