Injection-molding system including pressure-equalization circuit

An injection-molding machine (100), comprising:

• an air compressor (116);
• a valve-stem actuation solenoid (114) being connected with the air compressor (116);
• a hot-runner system (101), including:
• (i) an air-open circuit (110);
• (ii) an air-closed circuit (112), and (iii) a valve stem (104) being coupled with the air-open circuit (110) and the air-closed circuit (112), the valve stem (104) being configured to move responsive to a change in air pressure in the air-open circuit (110) and the air-closed circuit (112);
• and
• a pressure-equalization circuit (118) connecting with the air-open circuit (110), the air-closed circuit (112) and the valve-stem actuation solenoid (114), the pressure-equalization circuit (118) being configured to:
• operate in a by-pass operation mode, in which the pressure-equalization circuit (118):
• (i) disconnects, at least in part, the valve-stem actuation solenoid (114) from the air-open circuit (110) and the air-closed circuit (112), and (ii) connects the air-open circuit (110) with the air-closed circuit (112), and the air pressure between the air-open circuit (110) and the air-closed circuit (112) becomes equalized, at least in part, by recycling, at least in part, the air pressure between the air-open circuit (110) and the air-closed circuit (112);
• and
• operate in a pass-through operation mode, in which the pressure-equalization circuit (118):
• (i) disconnects and isolates the air-open circuit (110) from the air-closed circuit (112), and (ii) connects the valve-stem actuation solenoid (114) with the air-open circuit (110) and the air-closed circuit (112), and the air pressure in the air-open circuit (110) and the air-closed circuit (112) is independently controlled so that the air compressor (116) actuates, via the valve-stem actuation solenoid (114), movement of the valve stem (104).

An injection-molding machine (100), comprising:

• a hot-runner system (101), including:
• a nozzle assembly (102);
• a valve stem (104) being received in the nozzle assembly (102);
• a valve-stem piston (106) connected with the valve stem (104);
• a piston-pressurization chamber (108) configured to receive the valve-stem piston (106);
• an air-open circuit (110) being connected with the piston-pressurization chamber (108);
• and
• an air-closed circuit (112) being connected with the piston-pressurization chamber (108);
• a valve-stem actuation solenoid (114);
• an air compressor (116) being selectively connected with the valve-stem actuation solenoid (114);
• an injection-molding machine controller (124), including:
• a first output (202) being connected to the air compressor (116);
• and
• a second output (204) being connected to the valve-stem actuation solenoid (114), the injection-molding machine controller (124) being configured to control the air compressor (116) and the valve-stem actuation solenoid (114);
• and
• a pressure-equalization circuit (118) connecting with the air-open circuit (110), the air-closed circuit (112) and the valve-stem actuation solenoid (114), the pressure-equalization circuit (118) being configured to:
• operate in a by-pass operation mode, in which the pressure-equalization circuit (118):
• (i) disconnects, at least in part, the valve-stem actuation solenoid (114) from the air-open circuit (110) and the air-closed circuit (112), and (ii) connects the air-open circuit (110) with the air-closed circuit (112), and air pressure between the air-open circuit (110) and the air-closed circuit (112) becomes equalized, at least in part, by recycling, at least in part, the air pressure between the air-open circuit (110) and the air-closed circuit (112);
• and
• operate in a pass-through operation mode, in which the pressure-equalization circuit (118):
• (i) disconnects and isolates the air-open circuit (110) from the air-closed circuit (112), and (ii) connects the valve-stem actuation solenoid (114) with the air-open circuit (110) and the air-closed circuit (112), and the air pressure in the air-open circuit (110) and the air-closed circuit (112) is independently controlled so that the air compressor (116) actuates, via the valve-stem actuation solenoid (114), movement of the valve stem (104).

A method of operating an injection-molding machine (100), comprising:

• operating in a by-pass operation mode, including:
• disconnecting, at least in part, a valve-stem actuation solenoid (114) from an air-open circuit (110) and a air-closed circuit (112), the valve-stem actuation solenoid (114) being connected with an air compressor (116), the air-open circuit (110) and the air-closed circuit (112) being coupled with a valve stem (104), the valve stem (104) being configured to move responsive to a change in air pressure in the air-open circuit (110) and the air-closed circuit (112);
• connecting the air-open circuit (110) with the air-closed circuit (112), and the air pressure between the air-open circuit (110) and the air-closed circuit (112) becomes equalized, at least in part, by recycling, at least in part, the air pressure between the air-open circuit (110) and the air-closed circuit (112);
• and
• operating in a pass-through operation mode, including:
• disconnecting and isolating the air-open circuit (110) from the air-closed circuit (112);
• and
• connecting the valve-stem actuation solenoid (114) with the air-open circuit (110) and the air-closed circuit (112), and the air compressor (116) actuates, via the valve-stem actuation solenoid (114), movement of the valve stem (104).