Why castings have a minimum quantity
A die or squeeze casting is economic once its tool and setup are spread over enough parts. Each production run has a setup cost: mounting the tool, bringing the die to temperature, first-off checks and the scrap before the process is stable. A minimum order quantity is how that setup cost is kept reasonable per part. It is a commercial number, set per part, not a property of the process.
Options for low volumes
| Option | When it fits | Trade-off |
|---|---|---|
| Machine from billet | Prototypes, very low volume, design still changing | Higher piece price; wrought material does not qualify the cast alloy |
| Single-cavity production tool | Low annual volume with a stable design | Full tool cost, lower than multi-cavity |
| Annual volume, scheduled releases | Steady demand, limited storage | Commit to an annual quantity; call off in batches |
| Combined runs | Several part numbers from one family | Planning across parts |
The crossover between machining from billet and casting depends on your own quotations; the break-even calculator on the billet conversion page uses them.
Prototypes and samples
A machined prototype proves geometry and fit. It does not prove that the cast part will hold pressure, reach T6 properties or pass X-ray. Plan the cast samples from the production tool as the qualification step, and keep the machined prototype for design checks.
What to tell us
- First order quantity and expected annual quantity
- Batch size you prefer per delivery
- Whether the design is frozen or still changing
- Lifetime of the programme, if known
- Whether parts are a family that could share runs