Statistical Process Control of the Tribocharging of Polymer Slabs in Frictional Sliding Contact

Besides the nature and condition of the surfaces in contact, several factors influence the triboelectric charging of polymer slabs in frictional sliding contact: pressure load and relative velocity between the two bodies, number of friction cycles, ambient temperature and humidity. This paper is aimed at pointing out the peculiarities of the statistic control of such a process. Thirty experiments were performed for the optimal combination of factor values (i.e., normal force: 10 N; sliding speed: 55 mm/s; number of sliding cycles: 10) that maximize the absolute value of the average potential at the surface of the tribocharged materials: 1600 kV. The capability index calculated from the experimental data was satisfactory and two Shewart charts were established for the statistical control of the process. Two out-of-control situations were simulated, in order to test the efficiency of the charts.