Patent ID: 8377350

Claim:
A method for controlling temperatures in hot runners of a multi-cavity injection mold comprising steps of: (a) positioning a temperature sensor in the same location of each of several cavities of the multi-cavity injection mold; (b) choosing one of the cavities as a standard cavity and defining a standard filling time as a time interval between the beginning of injecting a material into the standard cavity and when the material contacts the temperature sensor in the standard cavity; (c) injecting the material into the cavities through the hot runners connected with the cavities respectively, measuring time from the beginning of injection till the material contacts the temperature sensor in each cavity as a filling time of the cavity, and calculating the difference between the standard filling time and the filling time of each cavity as a temporal offset of the cavity; (d) if the temporal offset of at least one of the cavities is larger than a first preset value, adjusting the temperature in the hot runner which is connected with said cavity; and (e) repeating step (c) to step (d) until the temporal offset of each cavity is smaller or equal to the first preset value.