There is a problem that affects Small and Medium-sized Enterprises (SME), mainly in South America, where 53% of SMEs in Ecuador and 45% in Peru, eventually cease operations due to low efficiency rates due to a high rate of informality, and a lack of training and modern technology. As previous studies have successfully used the Lean Manufacturing methodology as a foundation to solve similar problems, we propose a combination of Lean Manufacturing tools due to address the root causes that of this problem and allow our case study company not only to remain in the market, but also to grow. Otherwise, the organization would be affected, and it would become one more statistical within the industry. The approach proposes combining Poka Yoke, the 5S, Standardization and Process Management techniques to increase the efficiency of metalworking SMEs. The validation was conducted using the Arena software, where a 24.22% increase in efficiency and a reduction in defective products was obtained. It can be confirmed the success of the combined implementation of engineering tools to solve low efficiency issues at a metalworking SME company.