Study of the variables that compromise the finished yield in architectural paints through the implementation of statistical process control

Abstract

Results of laboratory tests were analyzed in a company in the residential paint sector, which belongs to  the Sectorial Quality Program. To evaluate the measurement system, tests were carried out to determine  the specific mass of paints for non-industrial buildings and to determine the covering power of dry paint  and theoretical yield. The tests were carried out in white Premium acrylic paint, in order to assess  repeatability and stability. Statistical techniques were implemented: data treatment, Z-score and control  charts. Assessing the repeatability of a test together with the responsible operator and the influence of  physical characteristics over an estimated period. Through the Z score, the results were satisfactory,  demonstrating that the method used and the responsible operator presented good repeatability. Only one  result was questionable, making it possible to find the process variables. For stability, the study indicated  the inexistence of a relationship between the viscosity variation and the finished yield variation, and  through the control charts common and special causes were found. With the knowledge of the variables, the common causes will be controlled and the special ones eliminated, guaranteeing a higher quality in the  process through a statistical analysis.