Dual loop control of ceramic precursor extrusion batch

A method for controlling a shape of a ceramic precursor extrudate, the method comprising:

• selecting at least one of a predetermined core temperature of the extrudate, a predetermined skin temperature of the extrudate, and a predetermined flow rate of the extrudate, wherein the predetermined core temperature of the extrudate is selected to be within a temperature range of not less than 31° C. and not more than 37° C.;
• forming the extrudate by extruding ceramic precursor batch material through a barrel of an extruder and through an extruder die disposed at an outlet of the extruder, a barrel temperature capable of being regulated by a barrel coolant flow;
• measuring a batch material temperature of the material within the extruder upstream of the die;
• measuring the barrel temperature;
• determining a batch material temperature setpoint;
• determining a barrel temperature setpoint based on the measured batch material temperature and the determined batch material temperature setpoint as inputs, and without a batch material pressure as an input;
• determining at least one of a barrel coolant flow setpoint and a valve position based on the determined barrel temperature setpoint and the measured barrel temperature;
• and
• regulating heat transfer between the barrel and the batch material within the extruder by adjusting the barrel coolant flow based on the at least one of the determined barrel coolant flow setpoint and the valve position to achieve at least one of the predetermined core temperature of the extrudate, the predetermined skin temperature of the extrudate, and the predetermined flow rate of the extrudate, wherein the heat transfer is regulated sufficiently to maintain the core temperature of the extrudate to be within the temperature range.

A method for controlling a shape of a ceramic precursor extrudate, the method comprising

• selecting at least one of a predetermined core temperature of the extrudate, a predetermined skin temperature of the extrudate, and a predetermined flow rate of the extrudate, wherein the predetermined skin temperature of the extrudate is selected to be within a temperature range of not less than 27° C. and not more than 34° C.;
• forming the extrudate by extruding ceramic precursor batch material through a barrel of an extruder and through an extruder die disposed at an outlet of the extruder, a barrel temperature capable of being regulated by a barrel coolant flow;
• measuring a batch material temperature of the material within the extruder upstream of the die;
• measuring the barrel temperature;
• determining a batch material temperature setpoint;
• determining a barrel temperature setpoint based on the measured batch material temperature and the determined batch material temperature setpoint as inputs, and without a batch material pressure as an input;
• determining at least one of a barrel coolant flow setpoint and a valve position based on the determined barrel temperature setpoint and the measured barrel temperature;
• and
• regulating heat transfer between the barrel and the batch material within the extruder by adjusting the barrel coolant flow based on the at least one of the determined barrel coolant flow setpoint and the valve position to achieve at least one of the predetermined core temperature of the extrudate, the predetermined skin temperature of the extrudate, and the predetermined flow rate of the extrudate, wherein the heat transfer is regulated sufficiently to maintain a skin temperature of the extrudate to be within the temperature range.

A ceramic precursor extrudate control system comprising:

• an extruder comprising a barrel and an extruder die disposed at an outlet of the extruder, wherein the extruder is configured to form an extrudate comprising at least one of a predetermined core temperature, a predetermined skin temperature, and a predetermined flow rate by extruding a batch material through the barrel and through the extruder die;
• a barrel cooling device configured to provide a barrel coolant flow to the barrel;
• a batch material temperature sensor disposed within the extruder upstream of the die and configured to deliver a batch material temperature;
• a barrel temperature sensor configured to deliver a barrel temperature;
• a master controller configured to receive the batch material temperature from the batch material temperature sensor and a batch material temperature setpoint as inputs, wherein the master controller is further configured to determine a barrel temperature setpoint as an output based on the batch material temperature and the batch material temperature setpoints as inputs, and without a batch material pressure as an input;
• and
• a slave controller configured to receive the barrel temperature setpoint determined by the master controller and the measured barrel temperature received from the barrel temperature sensor as inputs, and configured to deliver at least one of a coolant flow setpoint and a valve position as an output, wherein the barrel cooling device is configured to provide the coolant flow to the barrel based on the at least one of the coolant flow setpoint and the valve position to regulate heat transfer between the barrel and the batch material within the extruder to achieve at least one of the predetermined core temperature of the extrudate, the predetermined skin temperature of the extrudate, and the predetermined flow rate of the extrudate.