Plastic Part Design Guide: Wall Thickness, Draft, Ribs, Bosses and Radii The basic rules that keep injection moulded parts free of sink marks, warpage and sticking – with diagrams for wall thickness, draft, holes, bosses, ribs and corner radii. Read More October 21, 2025October 18, 2026 Posted in GuidesLeave a Comment on Plastic Part Design Guide: Wall Thickness, Draft, Ribs, Bosses and Radii