SYO JOE

Hello Six Sigma Community, I'm working on a quality improvement project for our automotive parts manufacturing line, specifically dealing with high-volume plastic components. We're experiencing a 2.3% defect rate in our injection molded parts, primarily due to: Dimensional variations - parts not meeting tight tolerance requirements (±0.05mm) Surface defects - flow marks, sink marks, and weld lines Warpage issues - especially in large, flat components Current State: Production volume: 50,000 units/month Current Cp: 1.12 (need to achieve 1.33) Main defects: 45% dimensional, 35% surface quality, 20% warpage What We've Tried: DOE on injection parameters (pressure, temperature, cooling time) Modified gate locations on some molds Implemented SPC charts for critical dimensions Despite these efforts, we're still not achieving our Six Sigma target of 3.4 DPMO. Questions for the Community: What structured approach would you recommend for systematically reducing these defects? Should we focus on DMAIC or consider DFSS for mold redesign? For those with injection molding experience, what are the most critical process parameters that impact dimensional stability? We've been researching advanced injection molding services and found that some specialized providers (like this comprehensive guide on plastic injection molding services) emphasize the importance of mold design optimization and precision manufacturing techniques. Has anyone had success partnering with specialized molding services for complex quality issues? What measurement systems and KPIs have you found most effective for tracking improvement in plastic manufacturing processes? How do you balance the cost of prevention (better molds, advanced process controls) versus appraisal costs in high-volume production? I'd appreciate any insights, especially from those who've successfully implemented Six Sigma projects in plastic manufacturing environments. Looking forward to learning from your experiences! Best regards,JOE