Method of controlling a manufacturing process using multivariate analysis
First Claim
1. A computer implemented method of controlling a manufacturing process, comprising the steps of:
- a.) during operation of the process, measuring the process with sensors of data representative of a plurality of process/product variables;
b.) in a computer, connected to receive data from the sensors using multivariate analysis, said computer generating a surrogate variable having a value representative of whether or not the process is in control, said surrogate variable being a function of a plurality of intermediate variables, each of said intermediate variables being a weighted function of the process/product variables;
c.) when the value of the surrogate variable is outside a predetermined limit, said computer determining which of the intermediate variables primarily contributed to the value of the surrogate variable;
d.) for the intermediate variable determined in the previous step, identifying which of the process variables primarily contributed to the value of the determined intermediate variable; and
e.) said computer modifying the process to change the process variable identified in the previous step to bring the value of the surrogate variable within the predetermined limit.
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Accused Products
Abstract
In a manufacturing process using multivariate analysis for statistical process control, data representing a plurality of process and/or product variables is collected during operation of the process. A surrogate variable, representing the overall state of the process is evaluated. The surrogate variable is a function of a plurality of intermediate variables, which in turn are a function of the process and/or product variables. When the value of the surrogate variable is outside of a predetermined limit, the contributions to the surrogate variable by the intermediate variables are calculated. The intermediate variable with the largest contribution is identified and the contributions to the identified intermediate variable by the process variables is calculated., The process variables with the largest contribution to the identified intermediate variable are identified, and used to diagnose and correct the problem with the process.
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Citations
18 Claims
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1. A computer implemented method of controlling a manufacturing process, comprising the steps of:
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a.) during operation of the process, measuring the process with sensors of data representative of a plurality of process/product variables; b.) in a computer, connected to receive data from the sensors using multivariate analysis, said computer generating a surrogate variable having a value representative of whether or not the process is in control, said surrogate variable being a function of a plurality of intermediate variables, each of said intermediate variables being a weighted function of the process/product variables; c.) when the value of the surrogate variable is outside a predetermined limit, said computer determining which of the intermediate variables primarily contributed to the value of the surrogate variable; d.) for the intermediate variable determined in the previous step, identifying which of the process variables primarily contributed to the value of the determined intermediate variable; and e.) said computer modifying the process to change the process variable identified in the previous step to bring the value of the surrogate variable within the predetermined limit. - View Dependent Claims (2, 3, 4)
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5. A computer implemented method of controlling a manufacturing process, comprising the steps of:
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a.) during operation of the process, measuring the process with sensors of data representative of a plurality of process/product variables; b.) in a computer, connected to receive data from the sensors using multivariate analysis, said computer generating a surrogate variable having a value representative of the overall state of the process, said surrogate variable being a function of a plurality of intermediate variables, each of said intermediate variables being a weighted function of the process/product variables; c.) when the value of the value of the surrogate variable is outside a predetermined limit, said computer determining which of the intermediate variables primarily contributed to the value of the surrogate variable; d.) for the intermediate variable determined in the previous step, identifying which of the process variables primarily contributed to the value of the determined intermediate variable; e.) comparing the pattern of process variables determined in the previous step to a known pattern of process variables representing a particular process failure; f.) when a match of said patterns of process variables is made, stopping the process; and g.) said computer modifying the process to change the process variables identified in the previous step to correct said particular process failure. - View Dependent Claims (6, 7, 8, 9)
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10. A computer implemented method of controlling a process, comprising the steps of:
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a.) during operation of the process, measuring the process with sensors of data representative of a plurality of process/product variables; b.) in a computer, connected to receive data from the sensors using multivariate analysis, generating a surrogate variable having a value representative of whether or not the process is in control, said surrogate variable being a function of a plurality of intermediate variables, each of said intermediate variables being a weighted function of the process/product variables; c.) when the value of the surrogate variable is outside a predetermined limit, said computer determining which of the intermediate variables primarily contributed to the value of the surrogate variable; d.) for the intermediate variable determined in the previous step, identifying which of the process variables primarily contributed to the value of the determined intermediate variable; and e.) said computer modifying the process to change the process variable identified in the previous step to bring the value of the surrogate variable within the predetermined limit. - View Dependent Claims (11, 12, 13)
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14. A computer implemented method of controlling a process, comprising the steps of:
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a.) during operation of the process, measuring the process with sensors of data representative of a plurality of process/product variables; b.) in a computer, connected to receive data from the sensors using multivariate analysis, generating a surrogate variable having a value representative of the overall state of the process, said surrogate variable being a function of a plurality of intermediate variables, each of said intermediate variables being a weighted function of the process/product variables; c.) when the value of the value of the surrogate variable is outside a predetermined limit, said computer determining which of the intermediate variables primarily contributed to the value of the surrogate variable; d.) for the intermediate variable determined in the previous step, identifying which of the process variables primarily contributed to the value of the determined intermediate variable; e.) comparing the pattern of process variables determined in the previous step to a known pattern of process variables representing a particular process failure; f.) when a match of said patterns of process variables is made, stopping the process; and g.) said computer modifying the process to change the process variables identified in the previous step to correct said particular process failure. - View Dependent Claims (15, 16, 17, 18)
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Specification