考虑过程能力和成本的刀具策略研究

Tool replacement method study based on process capability and cost

为了提高定期维修的刀具所加工的产品质量,减少停机时间和生产成本.考虑生产过程中工件尺寸的残差是时间的函数,利用Glejser检验方法,拟合工件尺寸残差符合的递增型异方差模型,提出了刀具磨损过程的过程能力指数计算方法;使用Bernstein概率密度函数描述刀具寿命和刀具磨损过程的一般特征,在每一个维修周期内均满足顾客要求的最小过程能力指数基础上,考虑质量损失、换刀成本、由刀具的突然失效引发的惩罚成本及维修刀具所需的成本,将过程能力与成本相结合,提出了用于确定最佳刀具初始状态和维修周期的模型.该模型为实际生产提供了一种离线的刀具管理方法.

To produce high quality products and reduce the downtime and cost of machines with periodically maintained tools during the cutting processes, the model of residuals of the tool wear process in traditional machine tools is fitted using Glejser test method which can test the increasing or decreasing heteroskedasticity of the process. Thus, the process capability index is developed for tool wear process. The Bernstein probability density function is applied to describe the general characteristics of tool life and the tool wear process. Based on the maintenance cycle which satisfies the required minimum process capability index of customers, by integrating process capability and cost, a tool replacement model to determine the optimal initial tool setting, tool maintenance cycle and tool replacement time is presented with regard to quality loss, replacement cost, penalty cost for possible tool failure and maintenance cost. The model can provide a method of off - line tool management in a production environment.