The invention provides a closed television system for viewing the pulsed laser beam machining of a workpiece said system including a TV camera tube which, in use, is pointed at the area of incidence of the laser beam on said workpiece, a rotary shutter in the optical path of said TV camera tube for intercepting intermittently the light passing along said optical path, and means for synchronising the pulsing of the laser and the rotation of said shutter so that, in use, said shutter prevents light from reaching said TV camera tube each time said laser is pulsed. The invention can be applied to conventional closed circuit television systems to produce a system for viewing the machining a workpiece with a pulsed laser beam without the bright light produced during such a machining operation permanently overloading the TV camera tube.
This invention relates to a dynamic beam/seam alignment control system for electron beam welds utilizing video apparatus. The system includes automatic control of workpiece illumination, near infrared illumination of the workpiece to limit the range of illumination and camera sensitivity adjustment, curve fitting of seam position data to obtain an accurate measure of beam/seam alignment, and automatic beam detection and calculation of the threshold beam level from the peak beam level of the preceding video line to locate the beam or seam edges.
Two pulse sequences are delivered by two lasers. A rotating segmented mirror having one or more reflective areas and one or more transmissive areas is rotated synchronously with the delivery of the pulse sequences to transmit pulses from one sequence, and to reflect pulses from the other sequence at intervals.
