Method and device for joining workpieces made from plastic in three-dimensional form by means of a laser beam

Abstract

A method for joining workpieces made from plastic, the upper workpiece, facing a laser source, consisting of a material transparent to the laser beam, and the lower workpiece consisting of a material absorbent to the laser beam, such that the mutually bordering contact surfaces for the two workpieces melt and are joined to one another under pressure during a subsequent cooling, the guiding of the laser beam onto the site to be joined, and the mechanical compression of the workpieces being carried out simultaneously by a machining head. The corresponding device comprises a machining head with focussing devices for the laser beam onto the contact surface, and pressure-exerting devices for compressing the workpieces. A rotatably mounted glass ball or roller is particularly suitable as pressure-exerting device. The invention permits welding quality to be assured in conjunction with flexibility of the welding operation without expensive and complicated damping balls.

1 - 5 . (canceled)  
     
     
         6 . A device for joining workpieces made from plastic, the upper workpiece, facing a laser source, consisting of a material transparent to the laser beam, and the lower workpiece consisting of a material absorbent to the laser beam, such that the mutually bordering contact services for the two workpieces melt and are joined to one another under pressure during a subsequent cooling, having at least one bearing surface for the workpieces, defined by a machining head ( 15 ) with focussing devices ( 2 ,  8 ) for the laser beam ( 14 ) onto the contact surface, and pressure-exerting devices ( 4 ) for compressing the workpieces ( 6 ,  7 ,  19 ).  
     
     
         7 . The device as claimed in  claim 6 , wherein on the end facing the workpieces ( 6 ,  7 ,  19 ) the machining head ( 15 ) has a ball ( 3 ) or roller ( 18 ) that is transparent to the laser beam ( 14 ).  
     
     
         8 . The device as claimed in  claim 7 , wherein the ball ( 3 ) or roller ( 18 ) is rotatably mounted.  
     
     
         9 . The device as claimed in  claim 8 , wherein the machining head ( 15 ) has a cavity ( 16 ) into which the end of an optical fiber ( 1 ) projects for coupling in the laser beam, optical devices ( 2 ,  8 ) are arranged in the cavity for shaping and guiding the laser beam, and the ball ( 3 ) or roller ( 18 ) is rotatably mounted at the lower end thereof.  
     
     
         10 . The device as claimed in  claim 9 , wherein a thermometer ( 11 ) can be coupled into the cavity ( 16 ).  
     
     
         11 . The device as claimed in  claim 6 , wherein the machining head ( 15 ) is resilient in the longitudinal direction.