Application of Six Sigma DMAIC and Failure Mode and Effects Analysis (FMEA) for Quality Improvement In Shielded Metal Arc Welding Training in Selected Technical Institutions in Imo State, Nigeria: A Comparative Study of Federal College of Land Resource T

Welding quality is influenced by process variation, operator competence, equipment condition, consumable handling and inspection practices. In technical institutions, recurring welding defects can reduce practical training quality, increase material wastage and weaken industrial readiness. This study applies the Six Sigma Define–Measure–Analyze–Improve–Control (DMAIC) methodology with Failure Mode and Effects Analysis (FMEA) to assess Shielded Metal Arc Welding (SMAW) training at Federal College of Land Resource Technology (FECOLART), Owerri, and Federal Polytechnic Nekede, Owerri, Imo State, Nigeria. The supplied study dataset contained 87 recorded defects classified into lack of fusion, undercut, porosity, slag inclusion, incomplete penetration and excessive spatter. Lack of fusion was the most frequent defect (25.29%), followed by undercut (22.99%) and porosity (21.84%); together these accounted for 70.12% of the recorded defects. FMEA identified lack of fusion and porosity as the highest-priority failure modes, with RPNs of 245 and 240 under the study rating assumptions. The results demonstrate that DMAIC provides a structured improvement pathway while FMEA adds risk-based prioritisation. Recommended controls include standardised welding procedures, preventive maintenance, improved electrode storage, structured inspection, instructor development and periodic review of defect data and FMEA.