Injection Molded Electronics Enclosure | Snap Fits, Bosses, Ribs, Draft, DFM

The lid sits inside a raised base rim. That one decision lets all four cantilever snap fits mould in a plain 2-plate tool: each hook underside is formed by a shut-off pin through the base floor, so there are no slides and no lifters. Every face carries draft (1.5° on walls, 0.5° on ribs and bosses, 1° on slots and pins), and I checked it on the model with a ray test on every surface patch: no undercuts. Walls are 2.0 mm, with ribs and boss walls at 1.2 mm (60 %) to keep sink marks off the cosmetic faces. Screw bosses are cored and gusseted, and the cover parting line is hidden inside the base rim. The snap arms are sized by calculation: 1.31 % root strain, about 41 N to close and 81 N to open across all four snaps. Delivered: STEP assembly with coloured parts, three A3 drawing sheets with sections through the snap fit and the screw boss, and a one-page DFM callout sheet covering draft, wall thickness, snaps, bosses, gating, weld lines and the items a toolmaker would still check.