Research On Selective Assembly Method For Assembly Quality Of Mechanical Products

Assembly quality is an essential aspect for a product to win the market.Complex mechanical products usually consist of two or more parts.The quality of parts mainly depends on their machining accuracy.Due to random changes in the manufacturing process,the deviation of parts accumulates in the direction of the dimension chain,resulting in lower assembly quality.For mechanical products with high research and development costs,complex mechanisms and complex constraints,the manufacturing cost will be significantly increased,if only by improving the manufacturing accuracy.This paper proposes a quality optimization method for mechanical products in the assembly process based on the selection and assembly of high-quality mechanical products.The main research contents are as follows:(1)Aiming at the grouping problem of selective assembly under the multiobjective requirements for mass-produced mechanical products,a method based on local search strategy for non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ)is proposed.A comprehensive selective assembly model based on quality loss function and dimensional deviation is established.A combination of floating-point coding and integer coding is used to describe grouping selective assembly scheme.The grouping selective assembly problem is solved by NSGA-Ⅱ hybrid simulated annealing algorithm,which improve the local search ability,and compared with other methods to verify the effectiveness of the method.(2)In the process of product assembly for small batch and high precision requirements,for the assembly of mechanical products with complex assembly relationships and multiple dimension chains,the parts may appear to have one part in different dimension chains.The same part has multiple quality characteristics,and based on the mass loss function,the signal-to-noise ratio is introduced to construct a direct matching mass loss model for parts with various mass characteristics,and the NSGA-Ⅲ algorithm is used to solve the model to find the optimal solution.(3)In the assembly of mechanical products,when there are parts that require specific processing,it is proposed to establish a model for selecting and assembling mechanical products based on particular processing parts,aiming at the processing cost,and seeking the optimal solution.