TH12870B - Laser bonding methods and devices for joining different workpieces made of plastic, or for bonding plastic to other materials. - Google Patents

Abstract

DC60 (06/03/43) Methods and equipment for laser bonding of various plastics or for bonding various plastics to other materials that are brought into contact under pressure, where the workpiece closest to the laser beam is predominantly transparent to the laser beam, and the second workpiece has the highest possible absorption properties. By producing a laser beam shaped as a line on the contact surface between the workpieces and by the relative movement of the laser beam relative to the workpieces, the workpieces are precisely bonded only in the required bonding areas. This allows for highly accurate bonding, enabling the production of even micro-engineering components in short cycle times. These components are precisely joined together only at the required connection points. This allows for highly accurate welds, enabling even micro-engineering components to be manufactured in short cycle times.

Claims (15)

1. A method of laser bonding different bonding works (4, 5) made of plastic or bonding plastic to other materials where the top workpiece (4), facing the laser source (1), is made of a material transparent to the laser beam (2), and a second workpiece (5) is made of a material that absorbs the laser beam (2), so that the adjacent contact surfaces (7) of the two works (4, 5) begin to melt and fuse together upon subsequent cooling under a specific pressure characterized by the placement of a laser-impermeable shield (3) between the laser source (1) and the works (4, 5) to be bonded, to bond them in the bonding area (6) of some of the contact surfaces (7), where the structure (9) of the shield is larger than the wavelength of the applied laser beam (2), the laser source (1) is directed to the contact surface (7) in such a way that a line (8) is formed on it and the shield (3) is moved. 2. A method consistent with clause 1, which is characterized in which the laser beam (2) is aligned at a right angle over the junction area (6) of the contact surface (7). 3. A method consistent with clause 1 or 2, which is specified in which the additional connection force is applied when joining the workpieces (4, 5) to be joined. 4. A method consistent with clause 3 is specified in which at least one workpiece (4, 5) has an overhang in the direction of the other workpiece (4, 5) adjacent to the connection area (3) so that a cavity (18) is created between the contact surface (7) to be joined and the overhang (16) when the two workpieces (4, 5) are pressed together. 5. An approach consistent with one of the preceding claims, characterized by the relative velocity between the laser source (1) and the workpieces (4,5), is chosen to be as high as possible as a function of the maximum laser power required to achieve the desired melting temperature. 6. An approach consistent with one of the preceding claims, which is characterized by the selection of a width that is fundamentally equal to the width of the connection area. 7. A method consistent with one of the preceding claims, which is characterized by the laser beam (2) being induced by at least one semiconductor laser. 8. A method consistent with claim 7 is characterized in which the length of the laser line (8) is adjusted by the distance of the laser source (1) from the contact surface (7) and the corresponding adjustment of the power of the laser for the required melting temperature. 9. A method consistent with claim 7 is characterized in which the width of the laser beam (2) is maintained to a constant fundamental characteristic with variation in the distance of the laser source (1) from the contact surface (7). 10. A method consistent with one of the preceding claims, which is characterized by the relative motion between the laser beam (2) and the contact surface (7) being achieved by a mirror (21) which can be made to rotate around an axis or rotate around an axis (20) parallel to the contact surface (7). 11. A device for joining various plastic workpieces (4, 5) or joining plastics to other materials by means of laser beams, where the top workpiece (4) facing the laser source (1) is made of a material transparent to the laser beam (2) and a second workpiece (5) is made of a material that absorbs the laser beam (2), so that the adjacent contact surfaces (7) of the two workpieces (4, 5) are melted and fused together upon subsequent cooling under a specified pressure. The laser source (1) and a shield (3) made of a laser-impermeable material are placed between the workpieces (4, 5) to be joined and the laser source, where the structure (9) of the shield is larger than the wavelength of the applied laser beam (2), the laser source (1) is directed toward the contact surface (7) so that the alignment (8) is made. This occurs on the aforementioned objects and devices (21,22) for the continuous movement of the laser beam (2) and the workpieces (4, 5) in relation to each other. 12. An apparatus conforming to claim 11 is characterized in which the laser beam (2) is aligned at a right angle over the junction area (6) of the contact surface (7). 13. Equipment conforming to claim 11 or 12 is characterized in which the clamping devices (11, 12) are provided to clamp the workpieces (4, 5) to be joined together with the covering (3) before the joining operation. 14. An device that complies with one of the preceding claims 11 through 13, which is characterized in which the laser beam (2) is generated by at least one semiconductor laser. 15. An apparatus conforming to claim 14 is characterized in which a laser source (1) emits a laser beam (2) whose cross-section is lengthened in a manner consistent with the required width; such beam is deflected by a mirror (21) which can be rotated around an axis or rotated around an axis (20) parallel to the contact surface (7) and is arranged above a shield (3) and can be operated by a driver unit (22).