應用六標準差改善液壓幫浦在雙面研磨製程平面度最佳化研究

A Study of Applying Six-Sigma Methodology to Improve Flatness on Double Disc Grinding Process Capability in Hydraulic Pumps

張嘉寶(Chia-Pao Chang) ； 張崑龍(Kun-Lung Chang)

《創新與經營管理學刊》 5卷1期 (2014/07) Pp. 67-81

https://doi.org/10.6270/JIBM.2014.5(1)67

摘要

六標準差手法主要是運用品管與統計方法改善產品品質，用以減少不良品的成本與浪費。本研究主旨即在運用六標準差手法並以DMAIC五個步驟，定義（Define）、衡量（Measure）、分析（Analyze）、改善（Improve）和控制（Control），有系統的針對雙面研磨製程深入分析，在低成本且快速的原則下，找到影響製程能力的關鍵因素與最佳組合水準，並結合田口品質工程的參數設計方法，由個案公司製程之實證研究，獲得改善液壓幫浦製程能力之模式，從現有的研磨製程參數中，針對砂輪修整的頻率（dressing interval）、機頭下降壓力（pressure）、切削液流量（coolant flow rate）、砂輪轉速（wheel rpm），設計一個四因子三水準的實驗進行實證研究。本研究亦考量雙面研磨製程中各參數條件對於加工結果的關聯性，分析各上下砂輪研磨因子對於正逆轉（C.W. and C.C.W.）向量研磨製程後的總移除率（total stock removal rate）與工件厚度變化與平面度（flatness）的影響，以求得最佳參數進而提升雙面研磨的製程能力（Cpk）。本研究以齒輪幫浦的平面度為主要探討要因，期望能使尺寸公差達品質標準14.045 ± 0.005mm之界限，其品質特性屬於望目特性。結果顯示製程能力Cpk由0.49提高為1.33，驗證此結合模式能提高製程能力，加工壓力也從400公斤降至240公斤，除了減少研磨設備的耗損及節省電力，同時亦可增加砂輪壽命，提升製程品質能力的目標，也增加產能效益及降低製造成本。

關鍵字

顧客關係連結 ； 創新行銷 ； 主題遊樂園六標準差 ； 液壓幫浦 ； 雙面研磨製程 ； 田口實驗方法

並列摘要

The Six-Sigma is applied quality control and statistics to improve product quality for reducing the cost by yield rate. A research of Six-Sigma can be used five stages of DMAIC, which are Define, Measure, Analyze, Improve and Control, Base on lower cost to analysis double disc grinding process finds key factors and best levels to combine with Taguchi methods. In cases company to research hydraulic pump for improving process capability from grinding parameters such as wheel rpm, dressing interval, pressure, coolant flow rate, on the other hand we design four-factors with three-levels to study the result with each parameter in double disc grinding process, Analysis upper wheel and lower wheel relation with C.W. and C.C. W.. Total stock removal rate is dependent on vector grinding process with work-piece thickness variation of flatness. In order to achieve the best parameters to enhance double disc grinding process capability (Cpk), this research focuses on flatness of the gear pump and sets a target tolerances up to 14.045 ± 0.005mm, The characteristic of quality is nominal-the-best. The result shows Cpk value improved from 0.49 to 1.33, this combination can be identified the process of capacity. The pressure also reduced from 400 kg down to 240 kg, it could extend the life of machine and save power and increase the life of grinding wheel, reduce manufacturing cost also upgrade the target of quality.

並列關鍵字

six-sigma ； hydraulic pumps ； double-disc grinding process ； Taguchi methods