Continuous wave ultrasonic process monitor for polymer processing

An apparatus for continuously monitoring changing dynamic states of an injection mold having a cavity, comprising:

• an acoustic energy generator configured for coupling to the injection mold to apply continuous wave acoustic energy to the cavity;
• a frequency selector coupled to the generator and configured for adjustment to a range of frequencies including a resonant frequency for the cavity;
• and
• an energy monitoring device configured to monitor changes in parameters of the continuous wave acoustic energy resonant frequency and to control injection mold material flowing into the injection mold cavity based on the parameter changes monitored, wherein at least one characteristic of the cavity is determined based on the parameter changes monitored.

An injection molding apparatus comprising:

• an injection mold, having a cavity for receiving a polymer;
• a mold injector, coupled to the injection mold, to inject the polymer into the cavity to form a molded item made from the polymer;
• an acoustic energy generator that continuously produces acoustic energy to be non-invasively applied to the mold such that a continuous resonant frequency is produced within the injection mold;
• an ultrasonic emitter, coupled to the injection mold and the acoustic energy generator, to apply the acoustic energy from the acoustic energy generator to the injection mold;
• and
• an energy monitoring device responsive to the acoustic energy to monitor dynamic parameter changes of the continuous resonant frequency and to control injection mold material flowing into the injection mold based on the parameter changes monitored, wherein at least one characteristic of the polymer and at least one characteristic of the mold is determined based on the dynamic parameter changes monitored.

A molding process monitoring system, comprising:

• a sonic energy generator configured to impart a continuous wave sonic energy signal to a mold defining a cavity, said generator being configured to generate continuous wave sonic energy in a frequency range including a resonant frequency of the mold when the mold is empty;
• a sonic energy detector, configured to detect sonic energy returned by the mold and to detect change in at least one parameter of sonic energy returned by the mold;
• a processor configured to generate a signal indicative of an event in the molding process based upon changes in said at least one sensed parameter of the sonic energy returned by the mold;
• the system being configured so that a molding process can be monitored and injection mold material flowing into the cavity can be controlled based on said sonic energy imparted to and returned by the mold.