Property Optimization of EMI Compounds through the DOE Process
As more electronic devices are introduced, the prevention of Electromagnetic Interference (EMI) within and between these devices is becoming increasingly critical. Creating enclosures and shields from inherently EMI shielding plastic compounds represents a permanent and cost effective method for protecting these devices. However, to achieve optmum efficiency, these parts also need to be molded in a way that doesn't compromise the integrity of the EMI filler. The following two-level partial factorial Design of Experiment (DOE) study will examine the effect of 5 different injection molding process parameters on a Stainless Steel Fiber (SSF) filled polycarbonate (PC) compound. The study determined the most significant mlding parameters as well as the magnitude of significance of those paramaters. The result is a data driven set of process recommendations that can be applied to produce the best possible Shielding Effectiveness (SE) for a given compound. These results can then be applied to determine the lowest practical SSF filler concentration capable of meeting the EMI shielding design requirements for a given device in the most economical manner.