Process and apparatus for spot welding with a laser beam
First Claim
1. A spot welding process using a laser beam in which the welding of two members by spot welds comprises, for each spot weld, a first step of preparation by said laser beam of a weld region in which the spot weld will occur, followed by a second step of welding by said laser beam, said first step being adapted to modify a surface state in said weld region to obtain predefined conditions suited to the implementation of said second step, said first step comprising the following operations:
- a) directing said laser beam onto said weld region,b) measuring the value of at least one physical parameter that is characteristic of the surface state of said weld region to monitor the evolution thereof, andc) adjusting, during said first step, the characteristics of said laser beam as a function of the evolution of the value of said physical parameter, determined in operation b), in order to obtain said predefined conditions before implementing said second step.
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Accused Products
Abstract
The invention relates to a laser spot welding process for executing a spot weld in two successive steps, namely a first step of preparing the surface state of the material to be welded and a second step of welding as such. The luminous energy (BR) reflected by the weld region of the material is measured in real time during the first step and then processed by a controller circuit (37) connected to a control circuit (30) of the laser source (31). In this way, the characteristics (LM) of the laser beam are adjusted in real time as a function of the measurements effected to allow effective control of the quality of the weld obtained, and in particular of its dimensions.
The invention also relates to a welding device for implementing this process.
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Citations
18 Claims
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1. A spot welding process using a laser beam in which the welding of two members by spot welds comprises, for each spot weld, a first step of preparation by said laser beam of a weld region in which the spot weld will occur, followed by a second step of welding by said laser beam, said first step being adapted to modify a surface state in said weld region to obtain predefined conditions suited to the implementation of said second step, said first step comprising the following operations:
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a) directing said laser beam onto said weld region, b) measuring the value of at least one physical parameter that is characteristic of the surface state of said weld region to monitor the evolution thereof, and c) adjusting, during said first step, the characteristics of said laser beam as a function of the evolution of the value of said physical parameter, determined in operation b), in order to obtain said predefined conditions before implementing said second step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A spot welding device employing a laser beam and comprising:
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a laser source capable of emitting a laser beam in the direction of at least one weld region of a material to be welded, a control circuit of the laser source, regulation means for executing a spot weld in two successive steps, including a first or preparation step adapted to modify a surface state of said material to be welded in said weld region to obtain predefined conditions suited to the implementation of a second step comprising welding as such, said laser beam being directed during said first step onto said weld region of the material to be welded, said laser beam being used for welding during said second step in order to obtain a spot weld at the end of said second step, said regulation means comprising means for measuring at least the value of a physical parameter characteristic of the surface state of the material to be welded in said weld region and producing a first signal representative of said measured value, and a processor receiving the first signal and able to monitor the evolution of the value of said physical parameter, the processor being also adapted to produce during said first step a second signal that is a function of the evolution of the value of said physical parameter and to send this second signal to the control circuit of the laser source during said first step, in order to adjust the characteristics of said laser beam emitted during said first step to obtain said predefined conditions before implementing said second step. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification