Research On Rapid Prototyping System Development And Molding Process Based On Laser Sintering Technology

Selective laser sintering technology is one of the most promising rapid prototyping technologies.Compared with other rapid prototyping technologies,it has the advantages of no support,abundant punching materials,and the ability to print complex shapes.The existing laser sintering equipment has disadvantages such as high price,inconvenient operation,and difficult expansion,which affect the promotion and application of laser sintering equipment.The laser sintering molding process is a complex physical and chemical process,which has many process parameters that affect the quality of sintering molding and is difficult to observe through experiments.Aiming at the above shortcomings,this thesis carried out the research and development of a low-power laser sintering rapid prototyping equipment based on the design requirements of low cost,user friendly and high extensibility.On this basis,we used the method of numerical simulation to explore the influence of process parameters on the sintering process.The main work and results of this thesis are as follows:Based on the morphological matrix method and the analytic hierarchy process,we selected a reasonable mechanical system plan,designed a new mechanical system and completed the development of a low-power laser sintering system.Solve the problem of leaking powder during the powder feeding method based on the finite element analysis and a movable powder feeding device was designed.Using "PC + microcontroller" control scheme,we have designed and developed a hardware circuit system that considers functional circuits such as power supply,motor drive,and communication between upper and lower computers.Through the method of "double cache",the difference between the serial port transceiver speed and the chip processing speed was solved,and the lower computer software system was developed.The simulation model of PLA powder sintering loaded with a laser light source was constructed in the FLOW-3D software.Then we studied the influence of different laser power and scanning speed on the sintering melt channel,and verified the rationality of the numerical simulation results through experiments.The influences of laser power,scanning speed,powder thickness and scanning spacing on the density and dimensional accuracy of sintered parts were studied by orthogonal experiment,and a group of optimal processing parameters were obtained.