Research On Risk Assessment Method Of Metal Powder Bed Additive Manufacturing Technology

Metal powder bed additive manufacturing technology is based on the principle of discrete accumulation.The CAD model is made into two-dimensional cross section by computer program.The metal powder with high purity and good sphericity is used as raw material,and the metal powder is melted by laser beam or electron beam to gradually form the workpiece.Because of its mature technology,convenient operation and high precision,it is widely used in mechanical manufacturing,aerospace and other fields,but there are many risks in its production,such as fire,explosion,suffocation and radiation injury.At present,there are few researches on the safety risk of additive manufacturing technology system of metal powder bed.In order to effectively improve the safety level of metal powder bed additive manufacturing technology,it is of great significance to study a set of general risk assessment methods and take corresponding preventive measures.On the basis of field investigation,experimental analysis and literature review,considering the explosion characteristics and process characteristics of metal powder for additive manufacturing,a risk assessment index system for additive manufacturing technology of metal powder bed was established,and the weight was calculated by using structural entropy weight method(SEWM).The fuzzy comprehensive evaluation method is used to build the evaluation model,carry out empirical analysis,and make the evaluation model computerized.The main conclusions are as followsFirstly,the explosion characteristic parameters of eight kinds of metal powders for additive manufacturing were tested by experimental means,and the effects of dust concentration,dust injection pressure and other factors on the explosion characteristic parameters were studied.Considering the explosion sensitivity(MIE,MIT_C,MIT_L,MEC)and explosion severity(P_max,(dp/dt)_max)of metal powder itself,the explosion risk grade of metal powder for additive manufacturing is divided by two-dimensional matrix.Secondly,based on the factors of personnel,materials,equipment and facilities,environment and management,and combined with the process characteristics of metal powder bed additive manufacturing technology,the risk assessment index system of metal powder bed additive manufacturing technology is constructed,which contains 5 first level indicators and 19second level indicators,and the weight of each index is calculated based on the structural entropy weight method(sewm).The fuzzy comprehensive evaluation method is used to build the safety risk assessment model of metal powder bed additive manufacturing,and an empirical analysis is carried out in a scientific research unit using typical metal powder bed additive manufacturing technology to verify the reliability and practicability of the risk assessment method,and some countermeasures and suggestions are put forward for the scientific research unit to improve the safety management level.Finally,the risk assessment program of metal powder bed additive manufacturing technology is developed.According to the risk assessment model of metal powder bed additive manufacturing technology,the Java Script language is used to program.The program can not only modify the weight of each index according to the actual situation,but also simplify the calculation process of risk assessment,which can reflect the whole assessment process more intuitively and comprehensively.The program also provides data download function,so that users can consult and modify it later.