Start with a complete drawing package
Use this checklist before you request a quotation or release a tool. It turns general design advice into feature-level decisions that can be recorded and approved. It does not assign one wall thickness, draft angle or radius to every casting: those values depend on alloy, process, size and function, and are agreed in the DFM review.
- As-cast model and finished (machined) model, or the differences marked in one controlled package
- 2D drawing with revision, datums, tolerances and material specification
- Surfaces that stay as cast, and those that are machined
- Sealing faces, load paths and cosmetic surfaces marked
- Acceptance criteria: leak, X-ray, mechanical, finish
Walls and sections
- Walls as uniform as the function allows; gradual transitions where they change
- Thick bosses and junctions cored out or flagged as hot spots
- No isolated heavy section that solidifies last without feeding
- Sealing faces away from the last-to-freeze region where possible
Squeeze casting handles thicker walls than high-pressure die casting; see the squeeze casting design guide.
Draft and parting line
- Draft on every wall parallel to the opening direction, larger on inner walls and deep cores
- Draft kept distinct from chamfers: a bevel at an edge does not give the wall its taper
- Parting line placed away from sealing faces and cosmetic surfaces
- Undercuts removed or accepted as slides with their cost
Fillets, chamfers and edges
A casting supplier may propose a larger radius at a rib junction while the machining supplier asks for a smaller one beside a mounting face. Both can be right: one concerns the cast shape, the other the finished assembly. Give each disputed edge a feature ID and settle the interface first.
| Feature | Question to settle | Evidence to keep |
|---|---|---|
| Rib-to-wall junction | Does the blend keep the load path and avoid an abrupt section change? | Section view, local thickness review |
| Boss-to-base junction | Does a larger fillet add mass or block access? | Cast model section, manufacturing review |
| Mounting shoulder | Can the mating part seat beside the largest permitted radius? | Assembly section |
| Bore entrance | Lead-in, screw seat or edge break? | Mating part specification, feature callout |
| Machined pocket | Can the cutter reach the corner without changing the fit? | Tool-access review |
| Sealing boundary | Could the edge change reduce the sealing land? | Seal-interface review |
| Parting-line edge | How are split, trimming and witness controlled? | Tooling layout, post-trim acceptance |
Machining stock and datums
- Machining stock on every machined surface, enough to clean up without opening porosity
- Cast datum targets for the first operation, on stable surfaces
- Tapped holes not placed in the thickest section where shrinkage is likely
- Dimensions stated before or after coating
Tooling features
- Ejector-pin locations allowed, away from sealing and cosmetic faces
- Gate and overflow locations reviewed against sealing faces
- Text, logos and part marking raised or recessed, and their location
Record each decision
| Field | Entry |
|---|---|
| Part and drawing revision | controlled reference |
| Feature ID and function | location and reason |
| Proposed change | current, proposed, reason |
| Stage | as-cast, machined or deburred |
| Interface check | mating part revision, clearance decision |
| Acceptance | dimension, method, stage, sampling |
| Approved by | name, date |