Plastic product design appearance requirements

Such recesses could be eliminated from the design by reshaping the wall to maintain uniform thickness. If this is not possible for functional reasons or because of appearance, little can be done except to provide ample radii to facilitate the plastic flow. The product will probably require a slower molding cycle because of the special molding conditions required. 

Plastics offer the opportunity to optimize designs by focusing on material composition as well as product structural geometry to meet different product requirements. In structural applications for plastics, which generally include those in which the product has to resist substantial static and/or dynamic loads, it may appear that one of the problem design areas for many plastics is their low modulus of elasticity. Since shape integrity under load is a major consideration for structural products, low modulus type plastic products are designed shapewise and/or thicknesswise for efficient use of the material to afford maximum stiffness and overcome their low modulus. This type of plastics and products represent most of the plastic products produced worldwide. 

The lattice-type shelf is functionally as good as the others, but it may not look appropriate for a book shelf in the context of a library. A second consideration is a combination of physical requirements and appearance. A simple plastic beam that will function adequately in terms of strength and stiffness may be rather thin. A shelf of this type can look flimsy even if it is functional. This impression is useful to the designer since the solid plate is probably an uneconomical use of material. A requirement was added that the design should look like a wood shelf since this is the context in which it is to be used. To produce the desired thickness appearance either a lipped pan with internal reinforcement can be used or, alternatively, a sandwich-type structure with two skins and a separator core. In either case the displacement of the material from the plane of bending will improve the stiffness efficiency of the product. The appropriate procedure is to... 

Reinforced plastics (RPs) and unreinforced plastics (URPs) offer the opportunity to optimize plastic designs by focusing on material composition as well as product structural geometry to meet different product requirements (Figures 7.1 and 7.2). The minimum volume of plastic that will satisfy the structural, functional, appearance, and moldbility requirements of an application is usually the best choice. This is in sharp contrast to machining operations, where one starts with a solid block of material and machines away only until what one needs to make the part function remains. 

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