Siemens VDO Automotive (Germany), a supplier to the automotive industry, used Kistler's DataFlow data acquisition and monitoring system to compare the cavity pressure profile in eight individual mold cavities during molding of a PBT (polybutylene terephthalate) automotive part. Systematic error analysis of the complex injection molded automotive component before and after process optimization demonstrated that a mold cavity pressure based strategy could be used to improve significantly both the quality of the molded part and the process capability.
Preprocess optimization, the comparison for the eight cavities yielded a wide scattering of results. Taking a systematic approach, Siemens used the results to introduce improvements to the mold, hot runners, the hot runner control system, machine, machine parameters, and mold temperature control.A mold cavity pressure reference curve that coordinated the highest part quality with the best cycle times and the most reliable process performance was defined and specified within process tolerance limits.