Projeto piloto para a aplicação do controle estatístico de processo em um setor de produção de perfil em aço

Abstract

Statistical process control (SPC) applied in an organization provides quality control throughout the production chain, in other words, from the input of the raw material (input) to the finished product (output), through the use of statistical tools that help to visualize the performance of each process. So, with the growing competition in the productive sector for quality improvement, the use of statistical process control helps in decision making, continuous improvement of processes, implementation of new procedures and new methodologies. With this, the general objective of this work is to present the use of statistical process control in a productive sector of a metal-mechanic industry, which has the steel profile as its main product, representing about 80% of the company’s annual production. The SPC searches for possible variations that may impair production performance, which consequently affects the customers satisfaction. For this, the steel profile bending process was selected to act as a pilot analysis project inside of the company. Because this sector had a defect rate above 70% in the profile production line. A collection of production data was made and using the Minitab software, the X-bar and R-bar control charts were plotted to assess the stability of the process, these, in turn, demonstrated a non-stable process and, based on these results, it was possible to identify the root causes of the problems observed and apply improvements to the company’s production chain, in order to obtain better results in production performance and decrease in the production indexes. Industry defects. Finally, after the improvements applied, it was noticed through the new data collected for the preparation of the control charts, that the process obtained a significant improvement in its performance and showed capacity indexes higher than the stipulated minimum of 1.33 for 𝐶𝑝, 𝐶𝑝𝑘, 𝑃𝑝 and 𝑃𝑝𝑘 , reaching a 𝐶𝑝 index of up to 1.68. The results obtained in this study proved to be satisfactory, because through the SPC methodology and its tools, it was possible to reach positive levels of capacity and performance for a process that initially lacked stability. These results serve as a basis for implementing the SPC for the other processes. Of the production lines, as well as, to be incorporated to the control procedures already existing in the company.