Systems and Approaches for Manufacturing Parts

A molding machine comprising:

• a molding unit having a mold forming a mold cavity and a screw that moves from a first position to a second position, the injection unit adapted to receive and inject a molten plastic material into the mold cavity via the screw to form a molded part;
• a controller adapted to control operation of the injection molding machine according to a molding cycle;
• a first sensor coupled with the injection molding machine and the controller, the sensor adapted to measure a variable during the injection cycle;
• a second sensor coupled with the injection molding machine and the controller, the sensor adapted to measure a second variable during the injection cycle, wherein a relative position between the first sensor and the second sensor defines a known volume;
• wherein the controller is adapted to:
• commence injection of the molten polymer into the mold cavity,
• determine a first difference value between a first variable measurement obtained by the first sensor and a first variable measurement obtained by the second sensor,
• determine a second difference value between a second variable measurement subsequently obtained by the first sensor and a second variable measurement subsequently obtained by the second sensor,
• compare the first difference value with the second difference value, and
• adjust at least one control parameter based on a difference between the first and the second difference values.

A method for forming a part according to a cycle, the method comprising:

• introducing a molten polymer into a cavity;
• obtaining, using a first sensor, a first measurement of a first variable and a subsequent second measurement of the first variable during the cycle;
• obtaining, using a second sensor positioned downstream of the first sensor, a first measurement of a second variable and a subsequent second measurement of the second variable during the cycle;
• sensing, based on at least two of the first measurement of the first variable, the second measurement of the first variable, the first measurement of the second variable, or the second measurement of the second variable, a change in pressure of the molten polymer;
• and
• adjusting at least one control parameter based on the change in pressure of the molten polymer.

A method for controlling an extrusion molding machine having a die forming a molded parison, the extrusion machine being controlled by a controller according to an extrusion cycle, the method comprising:

• extruding a molten polymer through an extrusion die;
• obtaining, using a first sensor, a first measurement of a first variable during the extrusion cycle;
• obtaining, using a second sensor positioned downstream of the first sensor, a first measurement of a second variable during the extrusion cycle;
• obtaining, using the first sensor, a second measurement of the first variable during the extrusion cycle;
• obtaining, using the second sensor, a second measurement of the second variable during the extrusion cycle;
• determining a first difference value between the first measurement of the first variable and the first measurement of the second variable;
• determining a second difference value between the second measurement of the first variable and the second measurement of the second variable;
• comparing the first difference value with the second difference value;
• and
• adjusting at least one control parameter based on a difference between the first and the second difference values.