Measuring the supporting slats of laser cutting machines using laser triangulation

When automatically generating programs for flatbed laser cutting machines, it is advantageous to know the position of the supporting tips of the raw material. This allows the nesting layout and tool path to be adapted in an intelligent way. The problem of measuring the supporting tips of a laser cutting machine has not been considered in published literature before. We introduce possible methods first and choose a laser triangulation system. A novel setup, where none of the components is at a right angle to the measured surface, is proposed to account for the circumstances in a laser cutting machine. Its performance is investigated thoroughly with special regard to robustness and accuracy. In order to achieve very high accuracies, the setup is extrinsically calibrated on the measured object and different line extraction algorithms are tested for their effect on the measurement result. It is shown that the measurement setup is robust for different changes in the environment, such as different slat materials, bent supporting tips, and slagging. The measurement accuracy of the setup is calculated to be within ± 0.8 mm.