The study on laser sintering metal powder for micro fabrication

Laser sintering as an advanced manufacturing technology has been developed fast in the past years. It is an inevitable trend to adopt laser sintering metal powder material directly to make metal parts for rapid manufacturing. This work described a novel method of paving metal powders for laser micro sintering. A method of Rapid Manufacture for micro parts could be carried out by using the novel optical tweezers technology to manipulate micro metal powders to a defined shape and sintering the powders with laser. The novel method of optical tweezers is based on the theories of photon dynamics and the reflection force of laser photon to manipulate metal powers. The comparison experiments and studies are conducted to get the optimum process parameters. The result shows that different defocusing amount and reflectance of metal powders in manipulating the metal powders produce the different effects. When the metal powders are in the focal spot of the laser beam, this novel optical tweezers can provide the biggest trapping force, and higher reflectivity of metal powders has higher trapping force. The article also discusses numbers of factors which will influence laser sintering metal powders final result such as laser wavelength, laser power, diameter of laser beam, scanning speed etc. Through optimization in the parameters, a micro metal part has been successfully fabricated.