In many plastics injection moulding processing plants, resin dryers are a standard piece of equipment uses to remove moisture in hygroscopic polymer such as PC, ABS and PBT. These polymer exhibits some level of polarity in the functional group and therefore can absorb a certain amount of moisture from the atmosphere even in tightly sealed bag However many treated drying processes solely to bring moisture content to below supplier`s recommended moisture percentage or PPM. What some molders did not realised was varying moisture content even within its limit can cause poor moulded component quality. In certain material, moisture creates process sensitive and needed to be control with suitable technology in order to maintain the correct level of moisture and process robustness. In recent study of PBT material, moisture directly correlates with cyclic variation in moulding process output. Drying 3 – 4 hours to reduce the moisture content below 0.02% is not suffiecient, we also found between 0.02% and 0.01% of moisture caused significant variation in moulding process.

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