Optimization of Manufacturing Conditions for Rubber Sponge to reduce Load Deviation

Abstract

The quality of rubber sponge used for cars is greatly affected by the variability of ingredients and manufacturing conditions. It is the variation of compression load deflection which is the quality characteristic used to evaluate door closing and sealing functions. There are two kinds of causes: shape related and material related. In this report, material related cause was studied to reduce variability through the examination of the SN ratio which is calculated from the correlation between the compressed amount and compression load deflection. The curves due to the correlation showed non-linearity. The compression rate and reciprocating paths cause differences in the compression load deflection. Since these phenomena are the characteristics needed for rubber products, the quadratic term was studied.

As a result, 62.6% variability reduction was obtained for the case when all non-linear terms were considered as the error, and 62.8% variability reduction was resulted for the case when the quadratic term was not considered as the error. Further more, by studying the sensitivity of quadratic terms, the trends of processing conditions that affect the compression rate or the reciprocating paths of compression were found to be similar. That made possible to intentionally utilizing the hysteresis phenomenon.