## 3 Research Design  
The focal point of this research is to address the reduction in scrap generated during hipot testing within the subassembly manufacturing process of electric motors. The hipot test, conducted on site, involves subjecting the magnetic wire winding to a high-voltage withstand test. The primary objective of this test is to detect any weak insulation points [48]. During the test, an exceptionally high-voltage charge, surpassing the normal operating voltage, is applied between the conductors and their insulation. The examination tracks the leakage current flowing through the insulation, essentially assessing the product's ability to endure high-voltage stresses safely. Any insulation leakage triggers an alarm at the armature-level hipot tester, indicating improper continuity, a situation that should not occur. Therefore, it is imperative to identify the root causes of defects originating from this testing phase. It is essential to isolate the factor or combination of factors responsible for these defects; these can be found in the following sub-processes:  
* Lamination: This sub-process is responsible for generating the armature body, which is made of 60 layers of steel material called laminations. This number of laminations can vary until enough are stacked to achieve the armature stack length specification (Figure 1). Each lamination comes to the company under study from a stamping process performed by an external supplier. The first and last laminations that make up the armature are the same as the rest that are in the middle of them. For the union between the laminations to the shaft, a pressing device is used that introduced a shaft under pressure in the center of the laminations, which have a star-shaped cut, achieving a tight fit. For additional fixation, the device then makes a rivet on both sides of the laminations' center at the end of the process.
* Epoxy coating: This sub-process is responsible for generating electrical insulation by applying an epoxy resin in powder form along the entire interior of the armature body, covering from the first lamination to the last. Then, through a curing process, the powder is heated to form a solid layer (Figure 2).
* Wire winding: This sub-process involves a continuous series of winding from each bar on the commutator, which loops around the stack teeth and connects to the next bar on the commutator, using the stack slots to insert the wire winding from one side of the armature to the other (Figures 2 and 3). It is in this winding that the magnetic fields are generated for the speed that the motor will have. To perform this operation, an automatic winding machine is used in which the operator prepares the correct cable sizes and coil heads. Afterward, only the required dimensions and the number of turns need to be entered into the machine's computer; the rest of the process is automatic (Figure 3).  
Ultimately, this study aims to improve quality standards by minimizing scrap generated during armature manufacturing. The selected methodology, guided by the application of PDCA for defect and rejection reduction [49; 50; 51], consists of the following four primary steps:  
* Literature review: This phase involved analyzing published articles featuring case studies demonstrating the PDCA cycle in practice, as well as examining the individual PDCA phases, exploring the interconnections between PDCA and other improvement methodologies, and investigating its relationships with quality management systems.
* Case study development: This stage focused on constructing the specific case relevant for this research study.
* Results analysis: Following the implementation of the PDCA cycle, the obtained results were exhaustively analyzed.
* Conclusions and recommendations: Based on the findings, concrete conclusions were formulated, and practical recommendations for further improvement were provided.