Continuous seam welding apparatus and methods
First Claim
1. A method of producing a continuous seam weld between two mating surfaces during the passage of the surfaces relative to an energy source in a single pass, the method comprising the steps ofsupplying a bolus of energy from said energy source at alternate spaced locations along the line of the mating surfaces to effect local melting of the mating surfaces to form melt pools,allowing the bolus of energy to dissipate initially by way of an enlargement in the size of the melt pool and subsequently by cooling to a level at which the pool solidifies,supplying the bolus of energy from said energy source at intervening spaced locations along the line of the mating surfaces to effect local melting of the mating surfaces, andallowing the bolus of energy to dissipate initially by way of an increase in the size of the melt pool and subsequently by cooling, the spacing between the alternate and intervening locations and the power of the bolus of energy being of such magnitude that each pool produced at each intervening location increases in size sufficiently to overlap of said solidified pool at a said alternate location.
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Accused Products
Abstract
A method of producing a continuous seam weld between two mating surfaces of a can includes the steps of supplying a bolus of laser energy at alternate spaced locations along the line of the mating surfaces to effect local melting of the mating surfaces. The bolus of energy is then allowed to dissipate initially by way of an enlargement in the size of the melt pool and subsequently by cooling to a level at which the pool solidifies. A further bolus of laser energy is supplied at intervening spaced locations along the line of the mating surfaces to effect local melting of the mating surfaces. This bolus of energy is allowed to dissipate initially by way of an increase in the size of the melt pool and subsequently by cooling. The spacing between the alternate and intervening locations and the power of the bolus of energy being of such magnitude that the size of each pool produced at each intervening location during its enlargement overlaps a solidified pool.
79 Citations
26 Claims
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1. A method of producing a continuous seam weld between two mating surfaces during the passage of the surfaces relative to an energy source in a single pass, the method comprising the steps of
supplying a bolus of energy from said energy source at alternate spaced locations along the line of the mating surfaces to effect local melting of the mating surfaces to form melt pools, allowing the bolus of energy to dissipate initially by way of an enlargement in the size of the melt pool and subsequently by cooling to a level at which the pool solidifies, supplying the bolus of energy from said energy source at intervening spaced locations along the line of the mating surfaces to effect local melting of the mating surfaces, and allowing the bolus of energy to dissipate initially by way of an increase in the size of the melt pool and subsequently by cooling, the spacing between the alternate and intervening locations and the power of the bolus of energy being of such magnitude that each pool produced at each intervening location increases in size sufficiently to overlap of said solidified pool at a said alternate location.
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4. Apparatus for producing a continuous seam weld between two mating surfaces, the apparatus comprising
laser means energisable to produce a laser beam, means for supporting the mating surfaces and aligning them along a predetermined axis defining the site for the seam, means for effecting relative displacement between the laser means and the support means to cause the beam of the laser means to scan the site, and control means for controlling the laser means to direct successive discrete laser energy pulses to impinge upon the seam site to effect local melting of the mating surfaces in a series of overlapping zones, the control means being effective to ensure that at least every alternate pair of pulses produced do not impinge upon respective zones which overlap each other, wherein the control means causes each alternate pulse to be centred on a first axis extending parallel to and lying to one side of the central axis of the same and causes each alternate pulse to be centred on a second axis extending parallel to and lying to the other side of the central axis of the seam.
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5. A method of producing a continuous seam weld between two mating surfaces, the method comprising the steps of
applying a first succession of spaced discrete energy pulses to the mating surfaces progressively along the line of the seam to be formed, to effect local melting into melt pools of the mating surfaces, applying a second succession of spaced discrete energy pulses progressively along said line also to effect local melting into melt pools of the mating surfaces, the point of application of each pulse of the second succession being such that the pool of melt which it produces overlaps an area previously melted by a pulse of the first succession of pulses and the timing of each pulse of the second succession being such that it occurs during the period when the temperature of the said previously melted area has dropped by not less than 1% but not more than 25% of the temperature difference between the melting point of the material of the mating surfaces and ambient temperature.
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9. A method of welding an elongate seam between seam materials using a laser beam, said method comprising the steps of
assembling the seam material along the site of the eventual seam, causing relative motion as between the seam materials and the laser beam, and controlling the delivery of laser energy during a single pass between the laser beam and the seam materials to melt a plurality of overlapping zones, of the seam materials along the site of the eventual seam, each zone being melted by a discrete pulse of laser energy characterised in that in the area of overlap between two zones a period of time elapses between the heating of the two zones sufficient to allow one said zone to stabilise or solidify before the other is melted.
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16. Welding apparatus for producing a continuous seam weld between two mating surfaces the apparatus comprising
laser means energisable to produce a laser beam, means for bringing together and supporting the mating surfaces and aligning them along a predetermined axis defining the site for the seam, means for effecting relative displacement between the laser means and the support means to cause the beam of the laser means to scan the site, and control means for controlling the laser means to direct successive discrete laser energy pulses to impinge upon the seam site to effect local melting of the mating surfaces in a series of overlapping zones the control means being effective to ensure that at least every alternative pair of pulses produced do not impinge upon respective zones which overlap each other and that the welding operation is completed in a single pass.
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26. Apparatus for producing a continuous seam weld between two mating surfaces, the apparatus comprising
laser means energisable to produce a laser beam, means for supporting the mating surfaces and aligning them along a predetermined axis defining the site for the seam, means for effecting relative displacement between the laser means and the support means to cause the beam of the laser means to scan the site, and control means for controlling the laser means to direct successive discrete laser energy pulses to impinge upon the seam site to effect local melting of the mating surfaces in a series of overlapping zones, the control means being effective to ensure that at least every alternate pair of pulses produced do not impinge upon respective zones which overlap each other, wherein the control means causes each alternate pulse to be centred on an central axis of the seam and causes the odd ones of each intervening pulse to be centred on a first axis extending to and lying on one side of the central axis and the even ones of each intervening pulse to be centred on a second axis extending parallel to and lying on the other side of said central axis.
Specification