Original title: Application of Statistical Quality-Analysis Tools in the 8D Methodology for Manufacturing Quality Improvement
Arícia Motta, Beatriz Castro, Jocieli Fouchy, Lorena Viana +1 · September 2026
A factory made aluminum car parts that kept coming out with bent pins. To solve this, a team used a structured eight-discipline troubleshooting method alongside statistical analysis. They checked the parts, mapped out possible issues, and tested how the machinery shaped the pin angles. They discovered the root problem: an automated system broke down, forcing workers to handle hot waste metal parts called sprues by hand. Without standard instructions or proper training, this manual handling bent the pins. Once the team fixed this, things improved immediately. They retrained the operators, wrote clear work rules, and restored the automated system. These simple fixes stopped the bent pin defects, cut down part variations, and safely returned the factory process to smooth automated operation.
Imagine you are baking cookies using a recipe that requires precise timing. One day your oven timer breaks, so you have to guess when the cookies are done. Some batches come out burnt, others undercooked. You use a chart to track the baking times and find that the burnt ones all happened when you guessed. In this paper, the broken automation is like the broken timer, and the statistical analysis is like the chart that showed the problem was the guessing, not the recipe.
For any manufacturer relying on automated processes, a single automation failure can introduce hidden variability that standard quality checks miss. This paper shows how combining the 8D methodology with statistical tools like process capability and hypothesis testing can pinpoint the exact human factor causing defects. The result is a practical framework for restoring quality when machines break down.
This work is a single case study in one automotive supplier factory, focusing on a specific pin warping defect in an aluminum component. The findings may not generalize to other materials, processes, or industries. The abstract does not discuss the cost or time required for the corrective actions, nor does it compare the 8D approach to other problem-solving methods. The statistical analysis is limited to pin angle measurements from two injection moulding machines.
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Application of Statistical Quality-Analysis Tools in the 8D Methodology for Manufacturing Quality Improvement — Arícia Motta, Beatriz Castro, Jocieli Fouchy et al. — Eng—Advances in Engineering — doi:10.3390/eng7090490
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper.