摘要
在多线切割加工过程中,断线是最严重的质量事故往往导致昂贵晶体材料的报废。如何选择合理的工艺参数保证钢线可靠性成为实际生产中亟待解决的问题。提出一种多线切割线网可靠度的评价方法。假设不同磨损量下钢线的断裂强度符合威布尔分布,采用线性回归法求取不同磨损量下钢线断裂强度的威布尔参数,推导出磨损钢线可靠度与张力及磨损量函数关系,建立线网串联离散模型,结合可靠性理论评价线网可靠度。为了验证该方法的实际效果,进行加工实验对该方法进行验证。试验结果表明:威布尔分布能较好地描述磨损钢线的断裂强度分布;线网可靠度与钢线张力及线网磨损量存在复杂的非线性关系;当线网最大磨损量取4μm,7μm,10μm不同值条件下,当张力小于25 N,线网可靠度差别小,随着张力进一步增大,线网可靠度呈现抛物线降低,线网最大磨损量越大,线网可靠度下降速度越快;在张力为20 N、25 N、30 N条件下,线网最大磨损量从2μm到10μm时,线网可靠度分别呈现接近直线、平稳下降、断崖式下降后趋于平稳下降三种完全不同的现象。线网可靠度评价方法为合理选择张力控制最大磨损量防止断线事故的发生提供了理论依据。
Wire breakage is the most serious quality accident which leads to the expensive materials scrapped in multi-wire sawing. How to select reasonable process parameters assuring wire reliability is an urgent problem. In this paper a method for assessing wire net reliability is presented. Assuming the fracture strength distribution of the worn wire is accordance with Weibull distribution, Weibull parameters of the samples is obtained using linear regression method and function relation of the wire reliability between wire tension and wire wear loss is derived. Then the wire web series discrete model is built. Furthermore wire web reliability is evaluated combining reliability theory. In order to verify the actual effect of this method, the experiments are conducted to verify the method. The experimental results show that the Weibull distribution can better describe the fracture strength distribution of the worn wire samples. There is a complicated nonlinear relationship between the wire net reliability, the wire tension and the wire net maximum wear loss. When wire net maximum wear loss is 4 μm, 7 μm, 10 μm,if the tension is less than 25 N, the difference of wire net reliability is small. Otherwise the wire net reliability decrease as parabola type with the increasing tension. Wire net reliability drops faster as more wire net wear loss. When wire tension is 20 N, 25 N, 30 N and wire wear maximum loss from 2 μm to 10 μm, wire net reliability drops with different types. The curves like horizontal line, steady slope line and plunge dropping line respectively. This method provide the theoretical rule for determining the reasonable slicing process reducing the risk of wire breakage.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2017年第23期174-181,共8页
Journal of Mechanical Engineering
基金
天津科技创新体系及平台建设计划(14TXGCCX00011)
天津市高等学校创新团队培养计划(TD12-5043)
天津市高校"学科领军人才培养计划"(RC14-02)
天津职业技术师范大学科研发展基金(KJ15-03)资助项目
关键词
多线切割
断线
线网可靠度
威布尔分布
multi-wiresawing
wire breakage
wire net reliability ~ Weibulldistribution
