Multiple beam laser welding apparatus

A laser apparatus for welding together substantially 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 positioning mechanism operable to change the orientation of said laser energy relative said seamline,
• a sensing device for sensing spacing between the abutting edge portions of the blanks, and
• a controller for controlling the positioning mechanism in response to the sensed spacing,
• wherein said laser energy includes a multiple beam of two laser beams, each of said laser beams having an optic center spaced from the other and defining one end of a focal line.

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

• a 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 center, wherein the optic centres of said first and second laser beams are spaced from each other and each define one end of a focal line of said composite beam,
• a positioning mechanism for selectively varying the orientation of said output composite beam to move said focal line relative to said seamline between a first oriented position wherein said focal line is moved to a first orientation relative to said seamline, and a second oriented position wherein said focal line is moved to a second orientation relative to said seamline, the second oriented position being moved from said first oriented position,
• wherein said abutting portions of said workpiece blanks are welded by the steps of:
• activating said laser device to direct said composite beam towards said seamline portions,
• moving said composite laser beam and said sheet blanks relative to each other to move said focal line substantially along said portion of said blanks to be welded,
• substantially simultaneously with said step of moving, activating said positioning mechanism to move said focal line relative to said portion of said seamline to one of said first oriented position and said second oriented position determined by the spacing between the workpiece blanks at said portion.