The design of experiments technique and its variants are used in the industry to improve production processes. This article briefly demonstrates the usefulness of Taguchi's design of experiments in the manufacturing sector and combines it with a Lean-Sigma approach to solve quality problems. To evaluate the efficiency of the methodology, a metal-coating process was selected to reduce the variation caused by noise factors in the thickness of the coating layer. Similarly, the aim was to approximate the average thickness of the coating to the specifications required by the client. The complete system consists of an electrochemical process, in which the metal parts are subjected to changes in their chemical and physical properties. The process consists of ten steps: degreaser wash, rinse, deep wash, a second rinse, acid neutralization, rinsing, coating, rinsing, dipping in ink, and sealing. Employing the approach proposed in this research, the mean and variation in thickness were resolved over seven weeks, improving the CPK level of the process from an initial value of 0.2 to 2.5, representing a reduction from 20% of rework to 0%.