M Company BEF Reel Format Products Die Cutting Depth Quality Improvement

BEF are necessary parts of LCD back light module. China labor cost is increasing with rocket, then back light module plant assembles back light by auto-assembly machine but not by operators assemble manually. The back light plant request M company BEF product transfer from sheet format to reel format. Reel format BEF product need more accuracy cutting depth control to sheet format product. Poor cutting depth is the first complaint item of M company Dongguan plant. The difficult of the subject is make sure no poor depth cutting even constant variation of the top plate, bottom plate, pinnacle die, bottom premask thickness and variety of machine cutting depth, and robust cutting depth must be control in 10 to 20 um.First, the paper introduces the background and meaning about study of BEF reel format products die cutting depth quality improvement. And search related papers and books, and then defines the research scope and methodology, outline.Then, the paper introduces BEF converting processes and die cutting process. Find poor cutting depth is the first complaint item of M company Dongguan plant by pareto chart, and then fix the baseline before improvement by recent 6 months data.After that, the paper analyzes process by process map and cause-and-effect diagram. The paper also analyzes customer complaint data by two sample proportion test to verify different operators, shifts, machines and poor cutting items. And then screens K24 machine and over cutting are significant factors. Then combine the process and data analysis to verify the factors about attribute agreement analysis, bottom premask thickness variation, die quality and environment. Prove cutting depth attribute agreement and die quality are key factors. And also confirm K24 cutting depth is not stable by regression analysis and two sample t test. And also prove machine cutting depth stability is also key factor. And also measure process windows for cutting depth.Finally, to reduce the poor cutting depth risk by improve key factors. Improvement actions include maintain K24 machine, SOP for robust cutting depth, stopper device on tooling, die lifetime management, attribute agreement improvement and QC before shipping. Customer complaint and NG product return are significant reduce after take actions.The study result can also be applied to other industries die cutting process. And hope this paper can be useful for other industries.