Die casting, designed before the die is cut

Die casting is priced after engineering review. The cost of a cast part is mostly the cost of a die that must be designed first, and a casting request sent down the machining or printing route would be priced against the wrong process. Our engineers read your model, run a DFM review and publish an official quote that lists the die, the part price and the machining after casting as separate lines. You see what the tooling costs before you commit to it, and you can compare it with the cost of machining the same part at your volume.

A die is cut for one shape, and almost every decision that matters is made before the steel is cut. Our engineers repeat the DFM review before DVT and before tooling, and production tools are cut only after DVT closes the design.

The work starts with the design. Our engineers check draft angles, wall thickness, rib and boss shapes, the parting line and where ejector pins can touch the part. They mark the features that must be machined after casting, such as bearing bores, sealing faces and threaded holes, because a casting does not hold a machined tolerance.

Next comes a part you can hold. A printed part checks form and fit at no tooling cost. A machined part in the same alloy family checks strength, heat and fit in the real product. Both run through the portal, so the casting design is proven before money goes into a die. Many teams build their demo build and EVT units this way, and move to casting only when DVT has closed the design and the volume is known.

When the design is closed, the in-house tool room builds the die in H13 tool steel on 5-axis machines. Parts are cast on presses from 150–3000 t, and castings are checked by X-ray fluoroscopy for internal porosity. The Shenzhen factory then machines the critical features on its CNC lines, assembles the part with the boards and harnesses, and tests the finished unit. Tooling you pay for, including the die, belongs to you, and you may move it to another factory.

Die casting makes thin walls and complex inner shapes at a part cost that does not grow with complexity. A ribbed housing with bosses and a two-millimeter wall needs many setups to machine, and much material is cut away. The die makes it in one shot, and the part is often lighter too.

What casting cannot do is hold a machined tolerance or leave a machined surface. Cast parts are machined after casting on the features that matter: bearing bores, sealing faces and threaded holes. "Cast, then machine" is the normal route for this reason. Our engineers plan which features get machined as part of the casting design.

Use a printed part for form and fit, and a machined part when the prototype must carry load or be tested in the real alloy. Both need no tooling and are ordered online. The printing route accepts parts from 0.1 to 2000 mm per axis. The machining route offers four tolerance bands, from general ISO 2768 to ±0.02 mm.

Neither one replaces a casting at volume. Both replace waiting for a die while the design is still changing, which is the more common problem. Order prototypes through CNC machining or 3D printing, and see how a printed shell turned into a cast enclosure in our heat-pump controller case study.

The die commits you to one geometry. It is cut for one shape, with draft, parting line and ejector positions set for it. A change to a wall or a boss is a change to the tool. Removing metal from the part is usually possible. Adding metal means cutting steel out of the die, a much larger job.

Casting rewards a design proven by other means first. The DFM review before tooling matters most here, and it is one reason an engineer prices die casting. Read how our engineers sort design findings in DFM services, and the design rules in our die casting design guide.