A Case Study on the Six Sigma Application to Reduce Acoustic Noise Generated by Multi-layer Ceramic Capacitors

Six Sigma represents a methodology designed for error-free processes throughout a company. It provides great statistical tools and the DMAIC (Define-Measure-Analyze-Improve-Control) systematic model which help reduce process variation in many different manufacturing companies, especially in the automotive domain. The present study aims to improve the failure rate found in assembled printed circuit board assembly (PCBA) dealing with the effect called “singing capacitors” for multilayer ceramic capacitors (MLCC), in an automotive application for interior electronics. Multilayer ceramic capacitors (MLCC) can be found in almost every electronic device due to their small size, large capacity, and low price. The main material that MLCC’s have in their composition is the dielectric material Barium Titanate, which causes vibrations due to the piezoelectric and electro strictive effects. Six Sigma fostered the use of statistical tools like Histograms, Anderson-Darling Test, Regressions, Correlations, Interval Plot and Box Plot, to analyze the effect called “singing capacitors”. To better understand this phenomenon at an electronic level a harmonic analysis was also performed. Because the placement of capacitors according to their geometry is known as an option to reduce or eliminate noise in the specialized literature, this paper follows the evolution and improvement of the phenomenon of “singing capacitors” using different suppliers and the optimal placement of MLCCs on the PCB.