Although designing machines and dies for plastics processing is routinely done with the help of computer modeling and design programs, the results don't always hold up in industrial application. Therefore, it is essential for the designer to have an understanding of the underlying mathematical concepts and their limitations when working with these programs and/or trying to improve their output. This book presents a summary of the most important formulas and their applications to solve design and processing problems with plastics materials. Numerous practical examples guide the reader step-by-step through the computational routine of designing polymer machinery. The approach is unassuming and very practical to enable every engineer to apply these concepts in their daily work and improve their equipment and stabilize their processes.