Electric heating – Metal heating – By arc
Reexamination Certificate
2001-12-10
2003-07-29
Shaw, Clifford C. (Department: 1725)
Electric heating
Metal heating
By arc
C219S075000, C219S121630, C219S158000
Reexamination Certificate
active
06600133
ABSTRACT:
TECHNICAL FIELD
This invention relates to a welding system, and more particularly, to one useful when applied in performing high accuracy butt welding.
BACKGROUND ART
In recent years, a material called a tailored blank, which is formed by butting a plurality of steel plates having the same plate thickness and comprising the same material or having different plate thicknesses and comprising different materials, and integrating them by CO
2
(carbon dioxide gas) laser welding or the like, has been used as a molding material for a vehicle body panel of an automobile, etc.
When this type of tailored blank is used, tip materials, which have occurred as scrap during various pressing steps, can be used effectively, waste of the material is reduced, and the yield from the material is increased. When a tailored blank comprising a combination of a steel plate having a large plate thickness and a steel plate having a small plate thickness is used to mold a panel part of a predetermined shape, for example, other advantages are also obtained, such that weight reduction can be achieved compared with molding of the entire panel part from a single thick steel plate.
When a tailored blank is to be obtained by butt welding two steel plates, it is necessary to place on a table, which constitutes a horizontal surface, two steel plates to be butt welded, and either transport each steel plate toward a predetermined reference plate, or transport one of the steel plates toward the end surface of the other steel plate whose positioning has been completed upon its butting against the reference plate to butt the two steel plates against each other. Thus, a welding system for performing this type of tailored blank welding needs to have a transport device and a reference position locating mechanism for steel plates as materials to be welded.
When butt welding of materials to be welded is to be carried out, such as when a tailored blank is to be obtained by butt welding two steel plates, it is generally necessary to run a carriage bearing a welding head along a horizontal beam. By so doing, the welding head is moved along a weld line of a butt weld zone. From the viewpoint of the welding efficiency, it is desirable to move the welding head at a high speed. On the other hand, a demand for the accuracy of welding in a tradeoff relationship with the high moving speed is becoming harsh year by year.
In view of the above points, the preferred welding head for use in the welding system is a laser/arc combined welding head for simultaneous implementation of laser welding and arc welding which can perform welding with a large melting width (high groove tolerance) and a great penetration depth.
An example of this type of laser/arc combined welding head is a coaxial welding head proposed in Japanese Unexamined Patent Publication No. 1999-156573. The coaxial welding head (not shown) reflects laser light by a convex surface of a convex roof mirror to divide it into two beams, a first divisional laser beam and a second divisional laser beam, further reflects these divisional laser beams by a concave surface of a concave roof mirror to form a space portion between the first divisional laser beam and the second divisional laser beam, and places an arc electrode in this space portion to make the laser light and the arc electrode coaxial. This coaxial arrangement of the laser light and the arc electrode obtains the effect that the welding head can be downsized, and the effect that the welding head can be moved easily in an arbitrary direction.
However, when laser welding and arc welding are performed simultaneously using the laser/arc combined welding head according to the prior art, a metal vapor
05
generated by irradiation of a material
03
to be welded, such as a steel plate, with laser light
02
deposits on the tip of an arc electrode (arc rod)
01
, as shown in FIG.
36
.
Thus, the arc electrode
01
minimally discharges, or the deposited metal interferes with the laser light path to decrease the energy of the laser light
02
. That is, from the point of view of applying an arc discharge reliably to the material
03
to be welded, the arc electrode
01
should be rendered as close as possible to a laser light irradiation position
03
a
of the material
03
to be welded. From the viewpoint of avoiding deposition of the metal vapor
05
on the tip of the arc electrode, the arc electrode
01
should be made as remote as possible from the laser light irradiation position
03
a.
Hence, it is desirable to set the arc electrode
01
at an optimal position which satisfies both of the above requirements. However, optimal conditions for placement have not been obtained, because of the lack of an arc electrode adjusting mechanism.
The present invention has been made in view of the above-described prior art. The object of the present invention is to provide a welding system which has a combined welding head capable of performing combined welding under optimal conditions for placement of an arc electrode relative to a laser light irradiation position while effectively preventing deposition of a metal vapor on the arc electrode, and which can perform butt welding, such as tailored blank welding, with high efficiency and high accuracy.
DISCLOSURE OF THE INVENTION
The constitutions of the present invention for attaining the above object are as follows:
I) A welding system comprising:
a welding stage having a table forming a horizontal surface on which materials to be welded are placed;
reference position locating means having a reference plate which is contacted by an end surface of one of the materials to be welded, while protruding upward from an upper surface of the table, to position the end surface of the plate material, prior to butt welding for butting the end surfaces of the materials to be placed on the upper surface of the table and welding the end surfaces together, and which retreats downward from the upper surface of the table during welding;
transport means for materials to be welded, adapted to transport the material to be welded, which has been placed on the upper surface of the table, toward the reference plate, or the end surface of the one of the materials to be welded whose positioning has been completed upon contact with the reference plate;
a horizontal beam supported at both ends by vertical end struts, and disposed horizontally like a bridge over the welding stage;
a carriage traveling horizontally on the horizontal beam; and
a welding head loaded on the carriage, and moved along a weld line together with the carriage to weld a weld area of the materials to be welded which have been placed on the welding stage, and wherein
the welding head is a laser/arc combined welding head for simultaneously performing laser light irradiation and arc discharge of the materials to be welded, thereby welding the materials to be welded, and
further includes arc electrode position adjusting means for moving an arc electrode in a direction perpendicular to a direction of an optical axis of laser light applied to the materials to be welded, thereby adjusting the position of the arc electrode in the perpendicular direction relative to the position of irradiation with laser light in the materials to be welded.
According to the present invention, the material to be welded, which has been transported by the transport means, is brought into contact with the reference plate of the reference position locating means, and positioned thereby, and then the end surface of the other material to be welded, which has been transported by other transport means, is brought into contact with the end surface of the positioned material to be welded, to complete preparations for butt welding. In this condition, butt welding can be performed using the laser/arc combined welding head which travels together with the carriage along the weld line running along a butt zone of the two materials to be welded. That is, positioning for butt welding of the materials to be welded, and butt welding can be carried out automatically as a series of operations.
Ishide Takashi
Nagashima Tadashi
Nishikawa Kenji
Sakashita Hideshi
Watanabe Masao
Mitsubishi Heavy Industries Ltd.
Shaw Clifford C.
LandOfFree
Welding system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Welding system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Welding system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3028842