Quantitative measurement of component accessibility and product assemblability for design for assembly application
One of the important issues about product assemblability (PA) is to design a product configuration that will facilitate assembly operations. The product configuration in this paper means the arrangement of components within a product. When a product is assembled, every component has to be handled by an assembly agent from the feeding position to the composing position. During this action, the product configuration plays a critical role in the planning and execution of the handling task of each component. The influence of the product configuration on the accessible range of a component can be investigated by considering the accessibility of the component. With an assembly oriented product configuration a product can achieve maximal assemblability in terms of the accessibility of each component. A quantitative rating, referred to as component accessibility (CA), has been developed to measure the accessibility of a component of a product during the conceptual and preliminary design stages. The CA is defined as the reciprocal of the information required for an ideal assembly agent to manipulate the component to have collision-free straight-line destination approaching in the presence of other assembled components. This CA has not previously been quantified and thus designers have only been able to rely on their own experience in arranging the components of a product. With the help of CA, a designer can select an optimal arrangement of components for assembly operations, and the best method for joining mating components can be chosen accordingly. As a result of the provision of CA, traditional DFA evaluation methodologies can be reinforced and many DFA-related applications can be further explored. Another quantitative measure, referred to as PA, has been developed accordingly to quantify the assemblability of a product on the basis of accessibility of each component. The relationship between the information content of assembling a product and the information content associated with each component has been derived. It has been found that the relationship between PA and CA of each component is similar to the relationship between the resistance of an equivalent resistor and the resistance of parallel resistors in electricity.
quantitative measurement component accessibility product assemblability design for assembly