On-Time Delivery Improvement in an Injection Molding Process Applying a Problem-Solving Approach Based on Lean-Sigma and the MSA Effect

Mexico’s manufacturing industry is vital to the global economy. This industry has recently faced challenges due to the COVID-19 pandemic and globalized markets. Some developed countries can adopt innovative technologies; however, Mexico focuses on improving production processes with little investment, combined with existing resources and technology. Mexican companies use improvement techniques such as Six Sigma and Lean Manufacturing to achieve this goal. This study reports a method called Lean-Sigma that, unlike traditional methods that take months or even years to solve a problem, our method offers results in weeks, avoiding waste generation and speeding up decision-making. The proposed method consists of the following phases: identifying and measuring the problem, analyzing the root cause, developing a solution, and verifying the solution and control plan. The main characteristic of this approach is that it acts at the speed of Lean and uses engineering tools to solve problems and to demonstrate how the measurement system error could affect the achievement of the single-minute exchange of die (SMED). To validate the proposed method, a case study is presented in a plastic injection molding process in a manufacturing company located in Ciudad Juárez (Chihuahua, México), which has a late delivery rate that causes delays in the final assembly lines. Implementing the suggested strategy increased on-time deliveries from 77% to 99.36% in six weeks.