Cavity and core inserts
The two hardened blocks that form the part shape. The cavity is on the fixed half, the core on the moving half, and everything else in the die exists to hold, cool, fill and empty these two pieces of steel.
Tooling and mold manufacturing
Aluminum Die Casting Tooling and Mold Manufacturing
An aluminum die casting mold is a two-part hardened steel tool that forms the part cavity and withstands 40 to 100 MPa injection pressure for 80,000 to 150,000 shots. CharMax Precision designs and builds die casting tooling in-house from H13 tool steel heat treated to 46-50 HRC, with production tools completed in 25 to 40 days and T1 samples 5 to 7 days later.
In short
An aluminum die casting mold is a two-part hardened steel tool that forms the part cavity and withstands 40 to 100 MPa injection pressure for 80,000 to 150,000 shots. CharMax Precision designs and builds die casting tooling in-house from H13 tool steel heat treated to 46-50 HRC, with production tools completed in 25 to 40 days and T1 samples 5 to 7 days later.
Tooling is the one irreversible decision in a casting program. Once steel is cut, the gate position, cooling layout, ejection scheme and parting line are fixed, and every part produced for the next five years inherits them. That is why every die is validated by mold flow and solidification simulation before a single cavity block is roughed out.
Tooling is quoted as a one-time charge and the tool belongs to the customer. It is dedicated to your part, stored and maintained at our facility for the life of the program at no charge, and released to you on request.
Capability at a glance
| Cavity and core steel | H13 (1.2344 / SKD61) premium grade |
|---|---|
| Cavity hardness | 46-50 HRC after vacuum heat treatment |
| Die base | P20 or S50C, standard frame or custom |
| Tool life | 80,000 to 150,000 shots typical |
| Cavity configurations | Single, 2-cavity, 4-cavity, family and unit dies |
| Tooling lead time | 25 to 40 days, plus 5 to 7 days to T1 samples |
| Tooling cost | 3,000 to 25,000+ USD as a one-time charge |
| Simulation | Mold flow and solidification before steel is cut |
| Toolroom equipment | CNC milling, sinker EDM, wire EDM, grinding, polishing |
| Cavity surface finish | Ra 0.4 to 1.6 µm depending on part requirement |
| Scheduled maintenance | Every 10,000 to 20,000 shots |
| Tool ownership | Customer owned, stored and maintained on site |
What a die casting die consists of
A production die is an assembly of a dozen subsystems, each of which can be the thing that limits part quality. Understanding what they do makes tooling quotations readable rather than a single opaque number.
Die base and holder blocks
The mild steel frame that carries the inserts, mounts to the machine platens and takes the clamping load. Standard frames shorten lead time; large or unusual parts need a custom base sized to the platen and tie-bar spacing.
Runner and gate system
The sprue, biscuit, runner and gate that carry metal from the shot sleeve into the cavity. Gate cross-section is calculated from required fill time and gate velocity, and is the single most influential dimension in the whole tool.
Overflows and vents
Reservoirs at the last-to-fill regions that receive cold metal, oxide film and air, plus vent lands 0.1 to 0.3 mm deep that let air escape ahead of the metal front. Together they usually represent 10 to 20% of shot weight.
Cooling lines
Drilled channels 8 to 12 mm in diameter running 10 to 15 mm from the cavity surface, with jet cooling and bubblers reaching into cores and bosses. Their layout sets die temperature uniformity, cycle time and where porosity concentrates.
Slides and lifters
Moving steel that forms undercuts, side holes and external features that cannot release along the draw direction. Each is driven by an angle pin or hydraulic cylinder, adds a flash line, and needs its own wear and lubrication plan.
Ejector system
The ejector plate, return pins and 20 to 100 ejector pins that push the casting off the core. Pin count and distribution are calculated from the projected area of the part gripping the core so it comes off square rather than racked.
Guiding and interlocks
Guide pins, bushings and taper interlocks that align the halves within a few hundredths of a millimetre under load. Worn or undersized interlocks are the usual cause of a dimension drifting across the parting line over a tool's life.
H13 tool steel and heat treatment
H13 is the standard for aluminum die casting because of what happens to the die surface every shot. Metal at 660 to 700 °C hits steel at 200 °C, the surface expands, then die spray cools it back down within seconds. That thermal cycle repeats 100,000 times, and H13 has the hot hardness, thermal fatigue resistance and toughness to survive it where a general-purpose tool steel would craze within a few thousand shots.
The heat treatment matters as much as the grade. Cavity inserts are rough machined, stress relieved, then vacuum hardened and triple tempered to 46-50 HRC. Harder than 50 HRC gains wear resistance but loses the toughness that resists heat checking, and below 46 HRC the cavity erodes at the gate. Anyone quoting H13 without naming the hardness and the tempering cycle is quoting a material, not a tool.
Where a specific area sees unusual duty, we change the local specification rather than the whole tool: nitriding on core pins for wear, a higher-grade steel for gate inserts on abrasive high-silicon alloys, and replaceable inserts anywhere we expect to service a wear point.
| Component | Material | Hardness | Reason |
|---|---|---|---|
| Cavity and core inserts | H13 / 1.2344 / SKD61 | 46-50 HRC | Balance of hot hardness and thermal fatigue resistance |
| Slides and sliding cores | H13 | 44-48 HRC | Slightly softer to resist galling against the die base |
| Core pins | H13, optionally nitrided | 48-52 HRC | Small sections see the highest thermal and erosion load |
| Sprue bush and gate inserts | H13 | 46-50 HRC | Highest metal velocity in the tool, replaced as a wear item |
| Ejector pins | SKD61, nitrided | 55-60 HRC surface | Surface hardness resists wear in the guide hole |
| Die base and holder blocks | P20 or S50C | 28-32 HRC | Structural, does not contact molten metal |
| Guide pins and bushings | Bearing steel, hardened | 58-62 HRC | Alignment accuracy has to survive the tool's full life |
Material certificates for the cavity steel are supplied on request and the heat treatment record is retained with the tool file.
Mold flow and solidification simulation
Simulation is run before the die design is released, not after a problem appears. The model imports the part geometry with the proposed gate, runner and overflow layout, and predicts how metal fills the cavity in milliseconds and how it freezes over the following seconds. Changing a gate in software costs a day; changing one in hardened steel costs a week of welding and re-machining plus a new T1.
The output that matters is not a pretty animation. It is a set of specific answers: where does the last air pocket end up, which region freezes last and therefore holds the shrinkage porosity, does any surface see gate velocity high enough to erode the die, and after twenty consecutive cycles does the die surface temperature stay inside the 180 to 280 °C window everywhere.
The simulation report goes to you with the die design for approval. If it shows a problem that geometry cannot solve through gating alone, you will hear it then, with the specific feature named, rather than after tooling is built.
- Fill pattern and fill time, confirming the cavity completes before the metal front drops below coherency temperature
- Air entrapment map, used to position overflows and vents where the air actually ends up
- Last-to-freeze regions, which is where shrinkage porosity will concentrate and therefore where machined faces should not sit
- Gate velocity distribution, checked against die erosion and soldering thresholds
- Cyclic die thermal analysis over 15 to 20 shots, showing whether the cooling layout reaches steady state inside the target window
- Predicted distortion after ejection, which drives where support pads and ejector pins are placed
Single cavity, multi-cavity, unit die and family die
Cavity configuration is decided from annual volume, part size and how many different parts share the program. It is worth deciding deliberately, because it is the tooling choice with the largest effect on both upfront cost and long-run piece price.
Single cavity
One part per shot. Lowest tooling cost, widest process window, easiest to debug and to maintain. Suits programs up to roughly 150,000 parts per year, which covers the majority of industrial OEM work.
Multi-cavity
Two or four identical cavities on a geometrically balanced runner. Tooling costs 60 to 80% more per doubling and the job usually moves up a machine size, but casting cost per part drops 15 to 30%. Justified above roughly 150,000 parts per year.
Unit die
Interchangeable cavity inserts that drop into a shared master frame held on the machine. Tooling cost falls 40 to 60% because you buy only the inserts, at the cost of a restricted part envelope and a shared changeover queue. Ideal for small parts at 500 to 20,000 per year.
Family die
Two or more different parts cast in one shot. Saves one tool's worth of cost and locks the parts into a fixed production ratio permanently, so it only makes sense for matched-set assemblies such as a housing and its own cover.
What drives die casting tooling cost
Tooling ranges from about 3,000 USD for a small single-cavity tool to 25,000 USD and above for a large multi-slide or multi-cavity die. The spread is not arbitrary, and once you know which drivers apply to your part you can usually see where 20 or 30% of the cost is sitting and decide whether the feature causing it is worth keeping.
| Driver | Effect on tooling cost | What you can do about it |
|---|---|---|
| Part envelope and die size | Largest single driver | Steel volume scales with the cube of size; consolidating two small parts is often cheaper than one large one |
| Cavity count | +60-80% per doubling | Model the machine hours first; most programs never need a second cavity |
| Each slide or lifter | +800-3,000 USD each | A small geometry change often removes an undercut entirely |
| Geometry complexity and EDM hours | +10-30% | Deep ribs, sharp internal detail and textured pockets require electrodes and sinker EDM time |
| Cavity surface finish | +5-15% | Ra 0.4 µm polished cosmetic cavities take substantially more bench hours than Ra 1.6 µm |
| Cooling complexity | +5-10% | Jet cooling and bubblers cost money upfront and repay it in cycle time on every shot |
| Target tool life | +10-20% | Specifying 200,000+ shots means premium steel and heavier sections; state your real volume so the tool is not over-built |
| Textures, logos and date inserts | +300-1,500 USD | Removable date and cavity ID inserts are cheap and worth having for traceability |
Tooling is a one-time charge. It is not amortised into the piece price, so you see both numbers separately and can compare quotes without guessing which cost sits where.
Tooling lead time, stage by stage
Tooling lead time is 25 to 40 days for a single-cavity production tool, followed by 5 to 7 days for T1 sampling and the dimensional report. Multi-cavity tools and tools with several slides sit at the top of that range or beyond.
Two stages sit on the critical path more often than customers expect. Die design approval waits on your sign-off, so every day the drawing sits unreviewed is a day added to the tool. And any part geometry change after design release restarts the affected steel, because rough machining has usually already begun.
| Stage | Working days | What happens |
|---|---|---|
| DFM review and quotation | 2-3 | Geometry assessment, projected area, machine selection, written DFM report |
| Die design and customer approval | 5-7 | Full 3D die layout with gating, cooling, ejection and slides, issued for your approval |
| Mold flow simulation | 2-3, parallel | Fill, solidification and thermal analysis, reported with the die design |
| Steel procurement | 3-5, parallel | H13 blocks and standard components ordered against the approved design |
| Rough CNC machining | 4-6 | Cavity and core blocks roughed, cooling lines drilled, stress relieved |
| Vacuum heat treatment | 3-5 | Hardening and triple temper to 46-50 HRC, sent out and returned |
| Finish CNC, sinker EDM and wire EDM | 6-9 | Final cavity geometry, electrodes, ribs, ejector and core pin holes |
| Grinding, polishing and bench fitting | 3-5 | Parting face grinding, cavity polish, slide and lifter fitting |
| Assembly and function check | 2-3 | Cooling circuit pressure test, ejection stroke, slide travel, interlock fit |
| T1 sampling and dimensional report | 5-7 | First shots, process establishment, full dimensional measurement against the drawing |
Simulation and steel procurement run in parallel with design approval and do not extend the critical path. Total elapsed time from purchase order to approved T1 samples is typically 30 to 47 days.
Tool life, maintenance and refurbishment
An aluminum die casting tool is a consumable with a long life, not a permanent asset. Expect 80,000 to 150,000 shots from a well-built H13 die running A380 or ADC12, with the spread depending on wall thickness, gate velocity and how hard the thermal cycle is on the cavity.
Dies do not usually fail all at once. They degrade through four mechanisms, all of which are visible on the parts before they become critical: heat checking, which prints as fine raised lines on the casting surface, soldering, where aluminum welds itself to the die at a hot spot, gate erosion, which gradually enlarges the gate and shifts the fill balance, and core pin cracking on small deep features.
Every tool has a shot counter and a maintenance file. Scheduled maintenance every 10,000 to 20,000 shots keeps small problems from becoming re-cut jobs, and a mid-life refurbishment typically restores a tool to near-new condition for 10 to 20% of the original tooling cost.
- Every shot is counted and logged against the tool, so remaining life is a number rather than an opinion
- Scheduled maintenance every 10,000 to 20,000 shots covers cavity cleaning, polish, ejector and slide lubrication, and cooling line flushing
- Heat-checked areas are TIG welded with matching filler and re-machined, restoring surface quality without replacing the insert
- Gate inserts, sprue bushes, core pins and ejector pins are treated as replaceable wear items and are stocked as spares on high-volume programs
- A full refurbishment at mid-life costs 10 to 20% of original tooling and typically returns 50,000 to 80,000 further shots
- For programs above 300,000 lifetime parts we recommend budgeting a replacement tool built from the same validated design, which is faster and cheaper than the original because the engineering is already done
Tool ownership and design changes after T1
The tool belongs to the customer who paid for it. It is dedicated to your part, never used for another customer's work, stored and maintained at our facility for the life of the program at no storage charge, and released to you or shipped to another supplier on written request.
Design changes after T1 are normal. Roughly a third of programs need at least one change once real parts reach a real assembly. What matters commercially is which direction the change goes, because adding material to the part means removing steel from the cavity, which is quick and cheap, while removing material from the part means adding steel back, which requires welding or a replacement insert.
Adding material to the part
Steel is cut away from the cavity. Typically 3 to 7 working days and a modest charge, sometimes none if it is minor. Examples: thickening a wall, enlarging a boss, adding a rib.
Removing material from the part
Steel must be added back by TIG welding and re-machining, or by replacing a local insert. Typically 7 to 15 working days with a moderate charge, and the welded area is re-polished and re-verified.
Structural change
A new parting line, an added slide or a relocated gate usually means a new cavity insert set in the existing base. Typically 15 to 25 working days at 30 to 60% of original tooling cost.
Change control
Every change is quoted with cost and schedule before work starts, the die drawing is revised, and a new first article inspection is run on the affected features before production resumes.
Production evidence
Process details behind this capability
The equipment, controls and finished-part evidence used to deliver this operation in production.
Proof
Related production programs
Real parts we have manufactured that involved this capability.
Keep exploring
Related capabilities and resources
Manufacturing services
Aluminum alloys
Part types
Industries served
Further reading
Frequently asked questions
How much does aluminum die casting tooling cost?
A single-cavity production die for a small to medium part typically runs 3,000 to 12,000 USD. Larger parts, multi-cavity dies and tools with multiple slides range from 12,000 to 25,000 USD or more. Tooling is quoted as a one-time charge, remains dedicated to your part, and is stored and maintained at our facility for the life of the program.
What is your lead time from purchase order to first parts?
Production tooling takes 25 to 40 days depending on part complexity and cavity count, followed by 5 to 7 days for T1 sample production. After you approve samples, production lead time is 15 to 25 days including machining, finishing and inspection. For repeat orders on existing tooling, expect 15 to 20 days.
Who owns the die casting mold after it is paid for?
You own it. The tool is dedicated to your part, never used for another customer, and stored and maintained at our facility for the life of the program at no storage charge. If you want it shipped to yourself or to another supplier, we release it on written request along with the die drawings and maintenance history. Tooling is quoted as a separate one-time charge rather than being hidden inside the piece price.
How many shots does an aluminum die casting die last?
A well-built H13 die running A380 or ADC12 delivers 80,000 to 150,000 shots. Thin walls, high gate velocity and severe thermal cycling push toward the lower end, while thick-section parts on moderate pressure reach the upper end. Failure is gradual rather than sudden and shows first as fine heat-check lines on the part surface. A mid-life refurbishment at 10 to 20% of original tooling cost typically buys another 50,000 to 80,000 shots.
Can the die be modified after T1 samples?
Yes, and roughly a third of programs need at least one change. The cost depends on direction: adding material to the part means cutting steel out of the cavity, which takes 3 to 7 days and costs little, while removing material means welding steel back in or replacing an insert, which takes 7 to 15 days. Structural changes such as a new parting line or an added slide usually need a new insert set at 30 to 60% of original tooling cost.
What is the difference between a single cavity and a multi-cavity die?
A single-cavity die produces one part per shot and a multi-cavity die produces two or four on a balanced runner system. Multi-cavity tooling costs 60 to 80% more per doubling and usually needs a larger machine because projected area roughly doubles, but casting cost per part falls 15 to 30%. The break-even sits near 150,000 parts per year. Below that, a single cavity has spare machine capacity, a wider process window and lower risk.
What tool steel do you use for aluminum die casting dies?
Cavity and core inserts are H13, also designated 1.2344 or SKD61, vacuum hardened and triple tempered to 46-50 HRC. That hardness band is deliberate: above 50 HRC the steel gains wear resistance but loses the toughness that resists thermal fatigue cracking, and below 46 HRC the gate area erodes. Die bases are P20 or S50C at 28-32 HRC, and ejector pins are nitrided to 55-60 HRC on the surface.
How is our intellectual property protected?
We sign your NDA before receiving files and can sign a mutual agreement if you prefer. Your tooling is dedicated to your part and is never used for another customer, your drawings are not shared outside the engineering and production team assigned to your program, and we do not display customer parts or names in marketing material without written permission.
Request for quote
Get tooling cost and a build schedule for your part
Send a 3D model and 2D drawing. You will get a tooling quotation broken down by cavity count and slide content, a build schedule to T1, and a DFM report naming any geometry that is driving cost into the tool.
- Engineering response within 24 hours on business days
- Quotation within 24-48 hours of receiving 2D/3D files
- NDA signed before file review
- Free DFM feedback