Research On Process Evaluation And Optimization Of Multi-wire Sawing Silicon Rods Based On Green Manufacturing

"Made in China 2025"advocates the implementation of green manufacturing.In accordance with the meaning of the product’s full life cycle,it changes the traditional design,manufacturing technology and production methods,fully achieves"Manufacturing Green",and accelerates the establishment of a"green"feature manufacturing system.Green manufacturing gives priority to guaranteeing the function,quality and cost of products.On this basis,comprehensive consideration is given to the impact of the product on the environment,the consumption of resources and energy during the entire product life cycle from design,manufacturing,use to scrapping,so as to achieve the best.At present,more than 70%of the emissions that cause global environmental pollution come from the manufacturing industry,which generates about 6.2 billion tons of waste every year.With the rapid change of products,the type and quantity of waste are still increasing at a high rate.Green manufacturing is the only way for the sustainable development of traditional manufacturing industry.It is an important way for the transformation and upgrading of China’s manufacturing industry.It is also an effective means to improve China’s overall advanced manufacturing level and cope with the technological blockade and trade barriers of developed countries.This thesis is founded on the research of JKEDM-500,a dedicated machine of multi-wire sawing silicon rods,and the process of 130?m ultra-thin silicon wafers by multi-wire sawing technology developed by the research group in the past several years.Based on the green manufacturing decision goal,taking the process of multi-wire sawing silicon rods as the research object,the thesis presents a green process evaluation system and evaluation index for multi-wire sawing silicon rods.By establishing mechanical modeling of multi-wire sawing silicon rods,the main process parameters affecting the process of multi-wire sawing silicon rods are proved theoretically.The Taguchi method（Taguchi）and the response surface methodology（RSM）method are used to establish a reasonable test scheme and obtain valid experimental data.A multivariable nonlinear mathematical model between green process evaluation value of multi-wire sawing silicon rods V and its key process parameters is established.Finally evaluation of green process and optimization of process parameters are solved by Design-Expert 12.At the same time,influences of main process parameters on the green process evaluation value of multi-wire sawing silicon rods are analyzed.The main research contents of the full text are as follows:（1）Because of the uncertainty of the content of the green process evaluation sub-system in the green manufacturing system and the incompleteness of the green process evaluation research in national standards and enterprise standards,the green process evaluation system of multi-wire sawing silicon rods was built in accordance with the feature content of green manufacturing based on the processes of multi-wire sawing silicon rods.multi-wire sawing technology is the main processing method of brittle materials such as silicon rod,sapphire and engineering ceramics.（2）Referring to the content of the green technology evaluation system of the silicon wire multi-wire sawing that has been determined,the thesis establishes the evaluation indexes of green technology for multi-wire sawing silicon rods in accordance with the evaluation index determination principle,such as systematicness,typicality,difference,consistency,actibility,etc.These indexes include silicon wafer productivity rate q₁,wafer thickness q₂,total cost per unit product c₁,silicon consumption per wafer r₁,time cost per thousand wafers product t₁,energy utilization efficiency n₁,wastewater discharge amount e₁,COD discharge amount e₂and user satisfaction s₁,counting for 9 indexes totally.（3）A detailed definition of silicon wafer productivity rate q₁,wafer thickness q₂,total cost per unit product c₁,silicon consumption per wafer r₁,time cost per thousand wafers product t₁,energy utilization efficiency n₁,wastewater discharge amount e₁,COD discharge amount e₂and user satisfaction s₁are introduced in evaluation indicators.The calculation method of them are determined respectively.With the same process elements of multi-wire sawing silicon rods,the raw data of green process evaluation index of 156×156 solar silicon wafers processed by different key process parameters are standardized.The green process evaluation matrix of silicon rod multi-wire saw is obtained.Two combination evaluation methods with different objective degrees were used for comprehensive evaluation of green process evaluation matrix.One is a combinatorial evaluation method based on AHP and fuzzy comprehensive evaluation,and the other is a combinatorial evaluation method based on entropy method and TOPSIS.（4）With the same process factors such as multi-wire sawing equipment,diamond wire diameter and abrasive grain distribution,in order to get the key process parameters that affect multi-wire sawing silicon rods process and optimize multi-wire sawing process parameters,the thesis establish a mechanical model of multi-wire sawing silicon rods with consolidated diamond particles.The mathematical relationship between cutting force and key process parameters is obtained theoretically.It is proved that the process of multi-wire sawing silicon rods is closely related to the key process parameters such as steel wire tension,steel wire running speed and silicon rods feeding speed.Lastly the value ranges of key process parameters of are determined referring to similar sawing equipments and JKEDM-500.（5）In order to get the highest green process evaluation value of the multi-wire sawing silicon rods and corresponding combination of green process parameters,the thesis designs orthogonal test scheme by the Taguchi method to reduce times of experiments.A series of typical test results corresponding to the green process evaluation value and key process parameters are obtained.The combination of green process parameters corresponding to the maximum evaluation value of the multi-wire sawing silicon rods is the optimal green process parameters.Meanwhile,because the experimental data obtained by Taguchi analysis method is a set of discrete points,in order to get the optimal green process evaluation value and the corresponding process parameters within the continuous process parameters value range,the thesis uses the surface response method to establish a multivariable nonlinear mathematical model.The optimal mathematical model is got by analysis of variance and consistency test.Because of the complexity and high order nonlinear mathematical equations,RSM optimization method of Design-Expert 12 is used to solve the process parameters of multi-wire sawing silicon rods based on the decision goal of green manufacturing.Meanwhile,the influence of single process parameters and combined process parameters on the green process evaluation value of multi-wire sawing silicon rods are analyzed.The research results show that:when the steel wire tension is 27.844 N,the steel wire running speed is 1059.388 m/min,and the silicon rods feeding speed is1.086 mm/min,the multi-wire sawing process with the consolidated diamond particle achieves the highest green process evaluation value,which is 0.8312.