Dtm Corporation

Gerald L Manning

A selective laser sintering apparatus and method is disclosed, in which the laser power is controlled according to the scan velocity. The scanning system, which includes a pair of galvanometer-controlled mirrors for directing the aim of the laser beam, generates signals indicative of either the position or scan velocity of the aim of the beam, in either one or two directions. The signals are gated in the laser power control system so as to pass the signals only during those times at which the laser is to be turned on. A laser power control system receives the signals and, in the case of position signals, differentiates the signals to generate velocity signals. The velocity signals are used to derive a scan velocity, and the scan velocity is multiplied by the desired laser power at full scan velocity to produce a laser power control signal. By making the laser power dependent upon the scan velocity, a constant laser energy flux density is applied to powder at the target surface, even during acceleration and deceleration intervals at the beginning and end of a scan, respectively.

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Austin, TX, United States of America

Gerald L Manning