The variations of electrical conductivity and hardness across the thickness of an Al alloy 7010 plate under the temper condition T7651 were investigated. The electrical conductivity and hardness respond in a reciproca...The variations of electrical conductivity and hardness across the thickness of an Al alloy 7010 plate under the temper condition T7651 were investigated. The electrical conductivity and hardness respond in a reciprocal manner. Cross-sectional slices of the plate subjected to re-solutionising/natural ageing and re-solutionising/artificial ageing show the similar tendencies in property changes as in the as-received raw material. This clearly suggests that the property inhomogeneity across the plate thickness is inherent of the manufacturing route. The differences in properties through the plate thickness are due to the changes in the concentrations of the strengthening alloying elements in the solid solution and the associated changes in microstructure; these are believed to be mainly due to the nature of plate solidification and prolonged high temperature during the rolling operation. The combination of electrical conductivity and hardness can be used as an integral quality property indicator for assessing inhomogeneity of thick products.展开更多
The Quality Function Deployment （QFD） is a useful and representative methodology to transform customer needs into different level of requirements in a system hierarchy. Simplifications that are based on assumptions ...The Quality Function Deployment （QFD） is a useful and representative methodology to transform customer needs into different level of requirements in a system hierarchy. Simplifications that are based on assumptions are ubiquitous in the QFD, but these underlying assumptions possibly do not hold true, which renders the simplifications unjustified. Additionally, these assumptions are usually not verified within the context of the application domain. This paper identifies and illustrates eight hidden traps in QFD during the process of establishing the requirements, where the assumptions, and therefore, the simplifications made are not reasonable. These traps are implicit in the understanding of customer needs, establishment of system requirements and the flow down of these requirements to lower levels of the system hierarchy. Suggestions are given to help avoiding these hidden traps, thereby eliminating or alleviating their potentially detrimental effects. The intent of the paper is to make readers aware of these traps when applying QFD for the establishment of requirements, so that they may utilize QFD with a better understanding of its limitations and develop higher quality specifications.展开更多
文摘The variations of electrical conductivity and hardness across the thickness of an Al alloy 7010 plate under the temper condition T7651 were investigated. The electrical conductivity and hardness respond in a reciprocal manner. Cross-sectional slices of the plate subjected to re-solutionising/natural ageing and re-solutionising/artificial ageing show the similar tendencies in property changes as in the as-received raw material. This clearly suggests that the property inhomogeneity across the plate thickness is inherent of the manufacturing route. The differences in properties through the plate thickness are due to the changes in the concentrations of the strengthening alloying elements in the solid solution and the associated changes in microstructure; these are believed to be mainly due to the nature of plate solidification and prolonged high temperature during the rolling operation. The combination of electrical conductivity and hardness can be used as an integral quality property indicator for assessing inhomogeneity of thick products.
基金funding from the Humanity and Social Science Youth Foundation of Ministry of Education of China(12YJC630201, 14YJCZH213)the Natural Science Foundation of Shaanxi Province(2015JM7378,2015JQ7277)the National Natural Science Foundation of China(71402140)
文摘The Quality Function Deployment （QFD） is a useful and representative methodology to transform customer needs into different level of requirements in a system hierarchy. Simplifications that are based on assumptions are ubiquitous in the QFD, but these underlying assumptions possibly do not hold true, which renders the simplifications unjustified. Additionally, these assumptions are usually not verified within the context of the application domain. This paper identifies and illustrates eight hidden traps in QFD during the process of establishing the requirements, where the assumptions, and therefore, the simplifications made are not reasonable. These traps are implicit in the understanding of customer needs, establishment of system requirements and the flow down of these requirements to lower levels of the system hierarchy. Suggestions are given to help avoiding these hidden traps, thereby eliminating or alleviating their potentially detrimental effects. The intent of the paper is to make readers aware of these traps when applying QFD for the establishment of requirements, so that they may utilize QFD with a better understanding of its limitations and develop higher quality specifications.
