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DESIGN IMAGINEERING GUIDELINES FOR PLASTIC DESIGN • RTP COMPANY DESIGNING YOUR PLASTIC PART DESIGNING YOUR PLASTIC PART When designing parts for injection molding, the manufacturing process must be considered. Injection molding is a process in which solid thermoplastic resin pellets are melted, injected into a mold, and then cooled back to a solid state in a new form. During both the injection and cooling stages of the manufacturing process, there are several factors which will affect the quality of the final product as well as the repeatability of the manufactur- ing process. Following a few important guidelines during part design will help minimize problems during molding and in the field. Although it is not always possible to follow all of these guidelines, outlined on the following pages are some of the most fundamental recommendations when designing parts for injection molding. RTP Companys experienced CAE Analysts can provide material data assistance, structural analysis, as well as filling and warpage analyses utilizing Moldflow®. Product design review and consultation is available as a service to our customers, please contact your local RTP Company Sales Engineer or Business Development Manager. IDEAL CONDITIONS IN PART DESIGN IDEAL CONDITIONS IN PART DESIGN Connecting Rib T/2 to T/3 Rib Strengthening Gusset T/2 4T Nominal Wall T 2T R=T/2 2T Boss 2T R=T/4 (0.015 min) KEY DEFINITIONS KEY DEFINITIONS Amorphous Polymer - A polymer characterized by random entangled polymer chains. Generally amorphous materials have lower shrink and better dimensional stability than semi-crystalline materials. Anisotropic - Not the same in all directions. This term might be applied to shrinkage for materials that shrink differently in the direction of flow than they do across the flow direction. Filled materials usually exhibit anisotropic shrinkage. Cavity/Core - The cavity is the depression in the mold which forms