CNC車床之可靠度設計與分析

Abstract

在CNC (Computer Numerical Control)車床的開發中，可靠度設計與分析是一個至關重要的環節。針對可靠度設計，需要建立一套周詳準則，將CNC車床被要求之系統可靠度合理分配至各子系統及零組件。就此，本研究將一CNC車床拆解成八個子系統，並提出七項可靠度分配準則。在每一準則中，考量子系統對系統重要程度之不同，賦予各子系統相對權重。在分析方面，本研究建構一種全面故障率分配方法，首先確認CNC車床整體系統之平均故障間隔時間(Mean Time Between Failure, MTBF)，將其換算成故障率，再根據前述分配準則與權重將系統故障率合理分配至各子系統，並探討各子系統故障率、MTBF及其它可靠度指標差異的情況。源由於所蒐尋兩岸文獻資料與數據之不同，本研究也兼探討兩岸學者在CNC車床可靠度研究上的差異。透過案例示範，相信本研究所提可靠度分配方法可做為CNC車床或其它工具機可靠度設計與分析之參考。

In the development of CNC (Computer Numerical Control) lathes, a crucial stage is reliability design and analysis. For reliability design, it is necessary to establish a comprehensive set of criteria to reasonably allocate the required system reliability of the CNC lathe to various subsystems and components. To this end, this study breaks down a CNC lathe into eight subsystems and proposes seven reliability allocation criteria. Within each criterion, considering the relative importance of subsystems to the overall system, relative weights are assigned to each subsystem. In terms of reliability analysis, this study constructs a comprehensive fault rate allocation method. It first determines the Mean Time Between Failure (MTBF) of the overall CNC lathe system, converts it to a fault rate, and then reasonably allocates the system fault rate to each subsystem based on the aforementioned allocation criteria and weights. The study also explores the differences in fault rates, MTBFs, and other reliability indicators among subsystems. Due to differences in the literature and data collected from both sides of the Taiwan Strait, this study also examines the disparities in CNC lathe reliability research between scholars of both sides. Through case demonstrations, we believe that the reliability allocation method proposed in this study can serve as a reference for reliability design and analysis of CNC lathes or other machine tools.