Improving the reliability of complex technological processes at the design stage

Abstract

Product compliance with quality specifications is evaluated for individual operations or for the whole technological process consisting of several successive operations. The goal of such evaluation is to determine the probability that the system is able to manufacture products that comply with the standard documentation. The probability of complying with the specification for a single quality parameter of the product (parameter k ) is the probability of meeting the requirements of the standard documentation regarding this parameter for a unit of production manufactured at time t [1]: P k ( t ) = P { x L k ≤ x k ( t ) ≤ x U k } where x k ( t ) is the actual value of parameter k ; x L k and x U k are its lower and upper limits. The probability of compliance with the specifications on n quality parameters of the product, i.e., the probability of meeting the requirements of the standard documents regarding n parameters at once for a unit of production manufactured at time t , is P 1, …, n ( t ) = P { x L1 ≤ x 1 ( t ) ≤ x U1 ; …; x L n ≤ x n ( t ) ≤ x U n }. The coefficient characterizing the compliance with the specifications on the product parameters is K cs ( t ) = ( t ). The compliance with the specifications regarding each quality parameter is established on the basis of the known distribution of the corresponding parameter. The P k ( t ) values are mainly calculated.