What Information Should Be Included in a Prototype Sand Casting RFQ?
What Information Should Be Included in a Prototype Sand Casting RFQ?
A prototype sand casting RFQ should include a 3D model, 2D drawing, material grade, quantity, critical dimensions, machining areas, surface finish requirement, inspection needs, application context, target lead time and the intended next production stage. The supplier needs this information to judge pattern work, core design, casting risk, CNC post-machining, finishing and inspection before quoting.
A weak RFQ often asks only, "Can you quote this casting?" with one picture attached. That is not enough for a reliable prototype quote. The supplier may not know whether the part needs an internal core, whether a face must be machined, whether the alloy is fixed, whether the prototype must pass a leak test, or whether the buyer is only checking appearance. Missing information turns into assumptions, and assumptions often become cost changes after the order starts.
The RFQ should explain what the prototype must prove. A prototype for visual review can be planned differently from a prototype for pressure testing, bearing fit, assembly validation or production transfer. If the buyer wants the prototype to support a future pilot batch, the supplier should review repeatability, pattern adjustment, machining allowance and inspection records from the beginning.
Buyers preparing a quote package can also review rapid sand casting for fast prototypes and what makes rapid sand casting faster than traditional casting.
Prototype Sand Casting RFQ Checklist
RFQ Item | What to Provide | Why It Matters |
|---|---|---|
3D model | STEP, X_T or IGS file | Shows geometry, wall thickness, internal spaces and machining access |
2D drawing | PDF drawing with tolerances, datums and notes | Defines what must be controlled and inspected |
Material grade | A356-T6, 319 aluminum, ductile iron, stainless steel or another specified alloy | Controls casting process, heat treatment, machining and final performance |
Quantity | Prototype quantity and possible pilot batch quantity | Changes pattern cost logic, inspection effort and machining setup planning |
Machining areas | Marked faces, holes, bores, threads, datum pads and sealing areas | Prevents missing machining allowance or underquoting CNC work |
Surface finish | As-cast, blasted, painted, coated or machined finish expectations | Defines finishing cost, cosmetic acceptance and packaging protection |
Inspection needs | Dimensional report, material record, leak test, CMM or FAI | Creates evidence for approval and production transfer |
Validation purpose | Fit check, pressure test, load test, appearance review or production planning | Guides the supplier toward the right process and cost level |
The 2D drawing is especially important. A 3D model can show shape, but it rarely tells the supplier which dimensions are critical. If the buyer does not mark datums, tolerances, sealing faces and threaded holes, the supplier may quote a rough casting when the buyer actually expects a finished machined component. That mismatch creates delays and price changes.
Buyers should also state whether alternative materials are allowed. If A356-T6 is required, the supplier should quote that route. If the buyer only needs a lightweight aluminum prototype for fit and machining validation, the supplier may suggest another cast aluminum option. The material decision should be clear before pattern and core work begins.
Questions Buyers Should Answer Before Sending the RFQ
Before sending the RFQ, buyers should answer several engineering questions. Is the part being validated for shape, load, pressure, corrosion, assembly or production transfer? Are internal passages functional or only part of a future design? Which surfaces must be machined? Which surface defects are acceptable on a prototype? Does the prototype need to match the final production material, or can an equivalent material be used for early validation?
Buyers should also explain the expected next step. If the prototype will be used for internal design review only, the supplier may recommend a faster or simpler route. If the prototype must support customer approval or pilot production, the supplier should prepare stronger documentation, controlled machining references and inspection reports.
How a Complete RFQ Prevents Later Change Orders
A complete RFQ prevents change orders by forcing the important manufacturing assumptions into the quote stage. If the sealing face is marked on the drawing, the supplier can include machining allowance and flatness inspection. If internal passages are identified as functional, the supplier can review core support and testing. If the buyer states that the prototype will be used for a pilot batch decision, the supplier can keep better records for pattern changes, machining setup and inspection results.
Many prototype disputes start because the buyer and supplier used different definitions of "prototype." The buyer expected a finished functional casting with machined interfaces, while the supplier quoted a rough casting for visual review. The RFQ should remove that ambiguity. It should say whether the expected delivery is a raw casting, a machined casting, a finished surface sample, an inspected first article, or a small batch ready for assembly testing.
Neway can review prototype sand casting RFQs and identify missing information before the project starts. A complete RFQ allows the team to quote sand casting, CNC post-machining, surface finishing and inspection as one connected prototype project rather than a rough casting with uncertain downstream cost.
