The Powder Spread System Improvement And Research On Molding Process In Selective Dual-laser Sintering

Selective laser sintering(SLS) is one of the most widely used rapid prototyping(RP)technology in the world. It is widely used in aerospace and other fields because of the widelyapplication and high efficiency of the materials and short production cycle.there are manyinsurmountable difficulties about one single light source laser rapid prototyping machineforming a larger size parts, but the two-light laser rapid prototyping machine can divided theparts into two parts at the same time molding.So it has high production efficiency.It hasimportant practical value.First designed the powder spreading system of dual laser sintering machine. The systemcomprising the synchronous drive freely move rapid prototyping cylinder, double rollerpowder spread device and the feeding mechanism. Contrast and analysis the characteristics ofthe duplex and triplex spread powder device, install the screw on both sides of the cylinderwall instead of the original screw set installation method to reduce the volume of a moldingmachine. Integrated vacuum feeding control circuit with the molding machine main controlprogram realized the automation of feeding.Secondly,analyze the characteristics of rollerspread powder device applicate in coated sand SLS, According to the flow characteristics ofresin coated sand to determine the friction factor of coated sand and spread powder roller, andregulate the slits opening width and installation height of powder storage funnel to effectivelyimprove the effective utilization rate of material.Third, Optimize the rollers`moving androtation speed of powder spread device and research the phenomenon of the parts have beencrush and move in sintering process, we add mesh support structure solve this problem.Research the process parameters of laser scanning. By measuring the critical exposureand penetration depth of the coated sand, we can conclude the relationship of the sinteringdepth and laser scanning speed and laser power according to the speed-power formula.Compared with the neck effect of layer in different laser power and scanning speed ofsintering, and do the bending test under appropriate laser power and scanning speed to optimize the sintering parameters; Finally we carries on the turbine blade and other large partssintering experiment.