Method and system for regulating an extrusion process
AssigneeThe Royal Institution for the Advancement of Learning/Mcgill University
InventorsBenoit Boulet, Raffi Toukhtarian, Mostafa Darabi
Life of this patent
Estimating the term…
Abstract
There is described a method and system for regulating an extrusion process by obtaining a first thickness at a first position along an extrudate as material is extruded through a die gap of a die; comparing the first thickness with an expected thickness of the extrudate at the first position to obtain a value for an error, the expected thickness modeled in real-time using a size of the die gap as input; and varying the size of the die gap when the error exceeds a threshold to compensate for the error. There is also described a method and system for determining an expected thickness of a material during an extrusion process.
Claims18
A method for regulating an extrusion process, the method comprising:
- continuously and in real-time, during a current extrusion cycle,
- obtaining a first thickness at a first position along an extrudate as material is extruded through a die gap of a die;
- comparing the first thickness with an expected thickness of the extrudate at the first position to obtain a value for an error, the expected thickness modeled in real-time using a size of the die gap as input and by applying a linear system with non-minimum phase dynamics and a unity DC gain;
- and
- varying the size of the die gap used in the current extrusion cycle when the error exceeds a threshold to compensate for the error.
A method for determining an expected thickness of a material during an extrusion process, the method comprising:
- in real-time during the extrusion process,
- obtaining a size of a die gap at a time T and a first position away from the die gap along an extrudate as material is extruded through the die gap;
- modeling a material transport delay from the die gap to the first position for the size of the die gap;
- determining a steady state thickness of the extrudate at the first position taking into account the material transport delay;
- replicating a change in the steady state thickness with respect to time to determine the expected thickness at the first position at time T, wherein determining the steady state thickness and replicating the change in the steady state thickness comprises applying the material transport delay model and a linear system with non-minimum phase dynamics and a unity DC gain;
- outputting the expected thickness of the material;
- and
- applying the expected thickness of the material in a feedback system for preventing machine drift during the extrusion process.
A system for determining an expected thickness of a material during an extrusion process, the system comprising:
- a processing unit;
- and
- a non-transitory computer-readable medium having stored thereon program code executable by the processing unit for:
- in real-time during the extrusion process,
- obtaining a size of a die gap at a time T and a first position away from the die gap along an extrudate as material is extruded through the die gap;
- modeling a material transport delay from the die gap to the first position for the size of the die gap;
- determining a steady state thickness of the extrudate at the first position taking into account the material transport delay;
- replicating a change in the steady state thickness with respect to time to determine the expected thickness at the first position at time T, wherein determining the steady state thickness and replicating the change in the steady state thickness comprises applying the material transport delay model and a linear system with non-minimum phase dynamics and a unity DC gain;
- outputting the expected thickness of the material;
- and
- applying the expected thickness of the material in a feedback system for preventing machine drift during the extrusion process.
Dependencies are inferred from the claim text.