本研究旨在運用精實與六標差管理流程,改善汽車保安零件油箱橫樑焊接之脫焊現象。汽車鈑件藉由點焊熔接使得兩素材黏合,而點焊機之條件設定中,電流(I)、壓力(Kgf)及通電時間(T)為點焊的重要因子,最後完成鈑件成品則以全破壞方式驗證熔接結果是否符合標準。油箱橫樑因牽涉人身安全,被車廠列為保安零件,若因脫焊致使駕駛人發生傷亡,車廠將面臨召回(Recall)壓力,不僅影響公司聲,還須負擔龐大賠償責任,因此各汽車製造廠均非常重視保安零件。本研究針對某車型裝置於保安零件3號橫樑之托架支撐油箱的點焊,運用實驗設計,從中獲得最佳生產條件,以杜絕脫焊問題的發生,達成產品品質要求;並透過精實管理與六標差管理流程,針對脫焊進行不良分析與改善。
This study implements the lean and six-sigma DMAIC management tool to analyze and improve the loose problem of spot welding of auto cross member and the oil tank. In welding machine configuration, electric current, machine pressure, and welding time are critical factors of spot welding. The final welded part is verified by destructive tests to see if it conforms to the specification or standard. The auto cross member and the oil tank parts directly involve human safety and are considered the safety parts by auto manufacturer. If loose welding problem happens and causes injury or casualty of passengers, the manufacturer would face strong pressure for a recall. It not only harms manufacturer’s reputation, but the manufacturer may also incur huge liability for damages. Therefore, almost all auto manufacturers put high emphasis on the safety parts. The quality of spot welding of #3 cross member and the oil tank of certain auto type is studied. By the design of experiment, the optimal configuration is achieved to reduce the loose problem of spot welding.