1. Freeze the evidence basis
Record part number, CAD revision, material grade candidate, appearance class, intended molding direction, units and responsible reviewer. Do not mix measurements from a prototype revision with a later production model.
2. Map wall thickness before secondary features
Run a CAD thickness analysis and retain the color scale or section locations. Record nominal, minimum and maximum walls and the source of the allowable deviation. Use the Wall Thickness Uniformity Checker without treating its result as a fill or warp prediction.
3. Measure ribs consistently
Measure base thickness where the rib joins its adjacent wall, height from that wall, clear spacing between parallel ribs, and the base radius. Note draft separately. Intersections, flow direction and a cosmetic opposite surface deserve explicit callouts.
4. Use the actual fastening system
For each boss, retain the actual screw or insert identifier, boss inner and outer diameter, wall thickness, base radius, attachment wall and nearby ribs. Supplier engagement and pull-out or torque testing cannot be replaced by a generic boss ratio.
5. Define draw and texture before measuring draft
Run draft analysis from each proposed draw direction. Record feature depth in that direction and obtain the exact texture or finish minimum from its supplier. Zero draft, negative draft, shutoffs and undercuts require geometry review rather than arithmetic.
6. Preserve the flagged-feature list
Export screenshots or section IDs for every flag, assign an owner, record the agreed action and link the revised CAD. Continue with the Feature Validation Before Tooling guide.
Sources: Protolabs wall-thickness guidance · Protolabs design essentials · Protolabs Designing for Mouldability · Covestro strategic-radii guidance.