> Air bubbles, shrinkage, crack, splash, sink-marks and intransparence are caused by hygroscopic plastic material which is not completely dried before molding. Hygroscopic materials such as PA, PC, PBT, PET, NYLON, etc, contain much humidity and cannot be dried completely by hopper dryers. > With dehumidifier, honeycomb rotor provides drying air with dew point under -40'℃ that can remove the humidity in the material and reduce it to 0.02% before molding.