Worksheet

The first step in selecting a plastic for a product to be fabricated is to determine its complete requirements. Since there could be a tendency to overlook certain properdes because they may appear to be insignificant or overlooked, it is vital to ensure that the product will perform during packaging, shipment, and/or in service. Selecdng an optimal material for a given product must obviously be based on analysis of the requirements to be met. A simplified approach involves comparing the specific service requirements to the potential properties of a plastic. What follows is a simplified but practical material-selection approach. This "longhand" system has been used for almost a half century during which time it became a basis in many fast computerized software material selection databases.

A simplified approach is where one starts by selecting the design criteria as well as potential plastics of interest and incorporating them into a table format checking off only the major criteria across the worksheet. Follow by setting up a comparison of the performance requirements for the potential plastics being considered and transfer the bold-faced numerical rating in each selected criteria column to the worktable. Add these numbers across the worktable to determine the plastic group with the lowest-point subtotal that will be the best plastic for a given application on a performance basis. Next add in the cost factor and total it to find the plastic group with the lowest number that results the best choice based on a cost-performance evaluation.

Follow by determining the specific plastic within the plastic group selected. The plastic with the lowest final total will be the best for the application on a cost-performance basis.

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