Research On Key Technologies Of Selective Laser Melting Equipment

SLM rapid prototyping technology is one of the most potential additive manufacturing technologies developed in recent years.Because of its simple molding process,good mechanical properties and direct molding of complex structural parts,it has been widely applied in the fields of biological medicine,aerospace and automobile mould.However,SLM technology currently still exists the problems of low powder coating efficiency and low molding precision of related equipment.In view of the above problems,The key technologies of the powder coating mechanism,the powder coating strategy and the forming cylinder mechanism in SLM equipment,were statied in this paper.Firstly,the overall design scheme of SLM equipment was put forward according to the process requirements of SLM technology.Secondly,the key technologies that affect the quality and efficiency of powder coating of SLM equipment were studied,mainly including three aspects: the structure design of the powder coating mechanism,the powder coating strategy of scraper deflection and the structure design of the forming cylinder mechanism.In view of the low efficiency and poor precision of manual leveling,a set of auto-leveling mechanism was designed in this paper.The leveling mechanism took optical fiber sensor as detecting element to adjust the distance between the scraper and the base plate.Powder coating strategy of scraper deflection was proposed in view of the problems of much idle running and low efficiency of scraper powder spreading.The dynamic relationship between the position of the powder coating and the height of the parts,the placement of the parts and the number of the layers of the powder was studied,and mathematical model of modified powder coating was established.In view of the low precision and poor reliability of the forming cylinder system,a set of platform lifting mechanism was designed in this paper.Moreover the structural optimization design was carried out by finite element analysis.Finally a set of experimental platform was built,mainly including container,base,powder feeder system,optics system,powder recovery system and control system.The reliability of key technologies was verified by the experimental platform.Automatic leveling mechanism designed in this paper,the design precision of the leveling of the scraper can reach 5?m,the leveling time can be reduced to a few seconds.In this paper,the research on the powder coating strategy of scraper deflection,a specific numerical example is given to show that the powder coating efficiency of this strategy has improved by 49.9%.The platform lifting mechanism designed in this paper,the maximum travel deviation of the base board can be controlled within 6?m.The experimental platform built in this paper can not only verify the reliability of the key technology,but also provide a guarantee for further research.