Quality control methods in the manufacturing industry : case study: Polyma industry

Abstract

This thesis investigates the effectiveness of quality control (QC) methods at POLYMA Industry, a lea ding plasturgy manufacturer in Tizi, Mascara, Algeria, specializing in plastic packaging for chemical and agro-food sectors. Anchored in a quantitative research approach, the study evaluates POLYMA’s QC system, certified under ISO 9001:2015 and pursuing ISO 22000, through statistical analysis of defect rates, process capability indices (Cp, Cpk), and sampling effectiveness. Utilizing SPSS and Excel, the research analyzes real QC data across six methods—Functional Test, Hardness Test, Packaging Control, Raw Material Control, Visual Inspection, and Final Product Check—revealing significant performance variations. Packaging Control exhibited the lowest defect rate (0.92%) and highest stability, while Visual Inspection (3.39%) and Functional Test (2.57%) showed elevated defects and variability, indicating inefficiencies. Statistical tests (ANOVA, Tukey HSD, Kruskal-Wallis) confirmed these differences, with high variability in Hardness Test attributed to insufficient sampling. Benchmarking against Six Sigma and ISO 9001 standards highlighted gaps in achieving near-zero defects, exacerbated by reliance on manual inspections, inconsistent testing frequencies, and limited automation. The thesis proposes adopting AI-driven inspections, real-time monitoring, and standardized protocols to enhance process stability and compliance with food safety standards. Findings underscore the strategic importance of integrating traditional and modern QC methods to ensure product quality, operational efficiency, and market competitiveness, offering actionable suggestions for POLYMA and insights for SMEs navigating quality management in resource-constrained settings