Multiple beam laser welding apparatus

A laser apparatus for welding together abutting edge portions of two sheet blanks along a seamline, the apparatus comprising:

• a laser head operable to emit laser energy to weld said blanks together along the seamline,
• a rotation mechanism for rotating the laser head and change the orientation of said laser energy relative said seamline,
• a sensor apparatus for sensing spacing between the abutting edge portions of the blanks, and
• a controller for controlling the rotation mechanism in response to the sensed spacing,
• wherein said laser energy comprises a multiple beam of at least two offset laser beams.

A method of using an apparatus to join together abutting portions of two workpiece blanks along a seamline, the apparatus including,

• laser device for emitting a composite beam to weld said blanks together along said seamline,
• said composite beam including a first laser beam and a second laser beam, each of said first and second laser beams being focused towards a portion of said blanks to be welded at respective focal areas having an optic centre, wherein the optic centres of said first and second laser beams are offset from each other and each define one end of a focal line of said composite beam,
• a rotation mechanism for selectively varying the orientation of said output composite beam to move said focal line relative to said portion of said blanks between a position wherein said focal line is oriented our of alignment with said portion of said seamline, and a position wherein said focal line is oriented substantially aligned with said portion of said seamline,
• wherein said abutting portions of said workpiece blanks are joined by the steps of:
• activating said laser device to direct said composite beam towards said seamline, moving said composite laser beam and said sheet blanks relative to each other to move said focal line along said portion of said blanks to be welded,
• substantially simultaneously with said step of moving, activating said rotation mechanism to move said focal line relative to said portion of said seamline to a preset position determined by the spacing between the workpiece blanks at said portion.

An apparatus for joining together proximal edge portions of two workpiece blanks along a seamline comprising,

• an emit for emitting a composite energy beam to weld said blanks together along said seamline,
• said composite energy beam including a first energy beam and a second energy beam, each of said first and second energy beams being focused towards a portion of said blanks to be welded at respective focal areas having a centre, wherein the centres of said first and second energy beams are offset from each other and each define one end of a focal line of said composite energy beam,
• a sensor for sensing any spacing between the proximal edge portions of the blanks, and a controller for changing the beam intensity per unit area selected from the group consisting of,
• a rotation drive for selectively rotating said emitter for emitting said composite energy beam to move said focal line relative to said portion of said blanks between a position wherein said focal line is oriented out of alignment with said portion of said seamline, and a position wherein said focal line is oriented substantially aligned with said portion of said seamline,
• a drive for moving said emitter for emitting said composite energy beam along said seamline, said drive activatable to vary the speed of movement of said energy beam depending on the sensed spacing between the proximal edge portions of the blanks, and
• a power regulating control to vary the composite energy beam energy output depending on the sensed spacing between the proximal edge portions of the blanks.