China United Mould

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Die Casting Molds

Tooling

Die casting molds designed for filling, cooling and die life

The die decides most of what happens in die casting: how the metal fills, where the air goes, how fast each section cools and how many shots the die lasts. A die casting die is a set of hardened hot-work steel cavity and core inserts in a mold base, with runners and gates, overflows and vents, water or thermal oil channels, slides for undercuts and an ejector system.

We design the die in 3D after the DFM review and build it in our own tool room with CNC machining, EDM and wire cutting. For porosity-critical parts we recommend a filling and solidification simulation before steel is cut; tell us if your project requires a simulation report.

Toolmaker fitting a die casting die in the tool room
Open die casting die in the machine, cavity insert for an aluminum housing

What goes into a die casting die

Die casting dies at a glance (typical)

Insert steelHot-work tool steel H13 / 1.2344, or premium ESR grades such as ASSAB 8407 for longer life
Insert hardnessTypically about 44–48 HRC for aluminum dies
LayoutSingle or multi-cavity, depending on part size and volume
GatingRunner, gates, overflows and vents designed for filling and venting
TemperatureCooling water and/or thermal oil channels
UndercutsSlides and core pulls
Trim dieSeparate tool to remove runners, overflows and flash

Die casting mold FAQ

How long does a die casting die last?

As a typical order of magnitude, an aluminum die in H13-class steel runs about 50,000–150,000 shots before the cavity inserts need replacing; heat checking, the fine thermal-fatigue cracks on the cavity surface, is the usual limit. Zinc dies often run several hundred thousand to over a million shots because zinc is cast roughly 250 °C cooler. Part size, gate design, die temperature control and maintenance move these figures a lot, so ask for the steel grade and expected life to be written into the die quotation.

Who owns the die?

Normally the customer who pays for the die owns it. Ownership, maintenance, insert replacement and storage are written into the quotation or tooling agreement.

Can you modify or repair an existing die?

Send us the die drawings, photos and a sample part. We review the condition and tell you what can be done.

Have a casting to quote? Tell us the part, the alloy and the annual volume.