Jena, Germany—Contour welding, quasi-simultaneous welding and simultaneous welding are used to laser join plastics. Each method has certain advantages and drawbacks. Galvo-scanners are used for quasi-simultaneous welding with the beam moving across the weld seam at high speed; along a freely programmable path. However, 3-D applications present difficulties because of shadows or unfavorable angles of incidence of the beam in case of a curved surface. Simultaneous welding uses open-end sources with direct beam projection on the weld. The weld geometry is composed of several segments but only straight lines up to about 20 mm in length are available. This arrangement cannot be programmed and changes are only possible by mechanical shifting or relocation, and the energy distribution cannot be varied within a line.
Jenoptik Automatisierungstechnik has developed a microscanner combining the flexibility and programming capability of the galvo-scanner with the scalability of the working field by using several beam sources.
In a 20-mm2 scan field, the microscanner generates line segments of any shape and energy distribution. Combining scan heads increases the scan field automatically by the software. The weld in each scan field is produced by contour method (localized) or quasi-simultaneous method (full heating). The energy distribution can be defined individually for each weld segment. The flexible individual position of each scanner ensures an optimal shadow-free angle of incidence for three-dimensional welds.
For very small weld geometries, a single microscanner with a scan field of 20 × 20 mm2 is an attractive cost alternative to the available galvanometric scanners. The maximum output of the welding laser is 5 to 30 W but the scan field is small so the energy density obtained is sufficient for welding plastic material.
Contact Jenoptik Autoimatisierungtechnik, [email protected], for more details.