Patent ID: 11858202
Assignee: LAWRENCE LIVERMORE NATIONAL SECURITY, LLC
Field: Materials, metallurgy (Chemistry)
Classification: CPC B  Y | IPC B

Claim 8:
9. An additive manufacturing system for forming a part using a laser powder bed fusion manufacturing process, the system comprising:
a computer configured to generate a mask sizing control signal;
a primary heat generating subsystem including a diode laser responsive to the computer for generating a fusing beam having a first power level for heating and fusing at least one of a plurality of select portions of a powder laid down to form a powder layer on a build plate, or an entire area of the powder layer deposited on the build plate;
a beam steering subsystem including a first electronically controllable mask, and being responsive to the computer, for steering the fusing beam over the powder layer deposited on the build plate;
a supplemental heating subsystem for generating a wide area beam having a second power level lower than the first power level, to heat a desired portion of the powder layer;
the supplemental heating subsystem including a second electronically controllable mask, controlled by the computer independently of the first digitally controllable mask through the mask sizing control signal supplied from the computer, the mask sizing control signal configured to control a size and a pattern of the wide area beam independently of generation and control of the fusing beam, and the computer further configured to supply a power control signal to the supplemental heating subsystem to provide control over the second power level, to enable simultaneously illuminating two independent areas of the powder layer on the build plate with differing selected intensities created by the first and second power levels associated with the fusing beam and the wide area beam, respectively;
the computer controlling the supplemental heating subsystem simultaneously while controlling operation of the primary heat generation subsystem and the beam steering subsystem, and the supplemental heating subsystem further being configured to heat the desired portion of the powder layer at least one of:
prior to fusing of the powder with the fusing beam;
simultaneously with fusing of the powder with the fusing beam; or
subsequent to fusing of the powder with the fusing beam;

the wide area beam being of an intensity which is insufficient to fuse the powder; and
the wide area beam having an intensity controlled by the computer through the power control signal applied to the supplemental heating subsystem, and operating to alter a microstructure of the powder layer as the powder layer is at least one of fused, or as the powder layer cools, to relieve stress in the part caused by heating created by the fusing beam, and to control an overall thermal history of the powder layer while being acted on by the fusing beam and the wide area beam.