Draft angle is a critical concept in plastic injection molding. It directly affects both the quality and manufacturability of plastic parts, so it’s crucial to get it right from the start to avoid production issues down the line. Worse, it can be a detail that can render your injection mold useless.
Put simply, draft angle refers to the taper or angle that is designed into the vertical walls of a plastic part, relative to the vertical axis of the mold. Properly tapered walls ensure that the finished part can more easily eject from the mold after the forming process is complete. Essentially, an optimal draft angle is necessary because it prevents the part from getting stuck in the mold cavity due to the friction between the plastic material and the mold surfaces on the texture side and the suction between the plastic material and the mold surfaces on the interior side.