Aluminum Die Casting: Alloys, Process, Tolerances & Cost (2026)

What aluminum die casting is — and why 2026 buyers care

Aluminum die casting is the process of forcing molten aluminum alloy into a hardened steel die at high pressure — typically 10–175 MPa of injection pressure — where it solidifies in seconds into a near-net-shape metal part. It is the highest-volume metal casting process in the world after sand casting, and for good reason: it combines aluminum’s light weight, thermal and electrical conductivity, and corrosion resistance with the repeatability of a steel tool.

The 2026 context makes the process more relevant, not less. EV battery housings, motor end caps and 5G/telecom enclosures are all specifying thin-wall aluminum die castings that must hold dimension, shed heat and survive vibration. Meanwhile, aluminum remains the default structural metal for anything that needs to be lighter than steel but stronger than plastic. If your product carries current, dissipates heat, or takes mechanical abuse, an aluminum die casting is probably on the shortlist.

This guide is written from the buyer-engineer side: which alloy to call out, what tolerances are honest to demand, where cost actually hides, and how to keep porosity from turning your first production run into a scrap event. We are a manufacturer ourselves — Dongguan-based, with die casting among our in-house processes — so the perspective is from inside the shop floor, and the numbers below are the ones we would quote against.

The Snapshot

• Best alloy for general use: A380 — the workhorse; strength, castability and cost balance (RapidDirect: https://www.rapiddirect.com/blog/aluminum-die-casting/).
• Best alloy for thin walls / Asia-market programs: A383 / ADC12 — higher silicon for fluidity; Xometry lists A383.0 as its ADC12 equivalent (https://www.xometry.com/capabilities/die-casting-services).
• Best alloy for structural, heat-treated, or semi-solid work: AlSi10Mg — lower iron, heat-treatable, higher thermal conductivity.
• Aluminum must be cast on a cold-chamber machine — molten aluminum’s temperature would destroy a hot-chamber gooseneck (RapidDirect).
• Typical tolerance: ±0.1 mm on general dimensions; ±0.05 mm on small critical features with steel-safe tooling; ±0.01 mm only via secondary machining (RapidDirect service page: https://www.rapiddirect.com/services/die-casting/).
• Wall thickness: 1–4 mm typical; 1.5 mm recommended minimum for aluminum; 0.8 mm achievable in small areas (RapidDirect).
• Die life: ~100,000 cycles for aluminum; ~1,000,000 for zinc (RapidDirect).
• Tooling cost: roughly $7,000–$75,000 depending on size, cavity count and complexity (RapidDirect).
• Aluminum die castings need a coating for corrosion resistance — as-cast aluminum does not self-passivate like as-cast zinc (Xometry).

Table of Contents

1. The Aluminum Die Casting Process
2. Aluminum Die Casting Alloys: A380, A383, ADC12, AlSi10Mg
3. Choosing the Right Alloy
4. Hot Chamber vs Cold Chamber vs Semi-Solid
5. Die Design: Parting Line, Gating, Ejectors
6. Tolerances: What Aluminum Die Casting Can Actually Hold
7. Wall Thickness: 1–4 mm Is the Sweet Spot
8. Surface Finishes: As-Cast to Anodized
9. Porosity: The Casting’s Signature Defect and How to Beat It
10. Cost Drivers: Where the Money Goes
11. Industry Applications: Automotive, Electronics, Telecom
12. Aluminum Die Casting vs Zinc Die Casting
13. [Aluminum Die Casting vs For the full process landscape see plastic molding services. Injection Molding](#aluminum-die-casting-vs-injection-molding)
14. DFM Checklist for Aluminum Die Castings
15. How We Approach Die Casting Programs
16. Frequently Asked Questions
17. Sources

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The Aluminum Die Casting Process

The process looks simple on paper: melt aluminum, inject it into a steel die, open the die, eject the part, repeat. The engineering lives in the details.

1. Melting — alloy ingots are melted in a furnace, typically at 660–700 °C for aluminum alloys (the melting point of aluminum itself is 660 °C; casting alloys run higher with superheat).
2. Injection — molten aluminum is ladled or dosed into the shot sleeve of a cold-chamber machine, then driven into the die cavity by a plunger at high pressure. Fill times are milliseconds; the metal enters the cavity as a spray that must wet the steel before it freezes.
3. Solidification — the die is water-cooled, so the metal freezes from the die wall inward. This is where shrinkage and porosity are decided.
4. Ejection — the die opens, ejector pins push the part off the core, and the shot — part plus sprue, runners and gates — is removed.
5. Trimming and secondary work — the runner system is cut off, flash is trimmed, and the part moves to machining, surface finishing or assembly.

The defining characteristic versus other casting processes is pressure: high-pressure die casting (HPDC) forces metal into the cavity before it can solidify, which is what makes walls as thin as 1 mm possible. The trade-off is that the violently turbulent fill traps air, which becomes porosity — the subject of its own section below.

Aluminum Die Casting Alloys: A380, A383, ADC12, AlSi10Mg

Four alloys cover the overwhelming majority of commercial aluminum die casting. Composition and mechanical values below are typical published values from NADCA and alloy supplier datasheets — exact numbers vary by heat, foundry practice and testing standard, so treat them as selection bands, not certification values.

Property (typical)	A380.0	A383.0 (US) / ADC12 (JIS)	ADC12 (as-specified)	AlSi10Mg
Primary designation	NADCA standard, US general purpose	US high-fluidity grade	Japanese JIS H 5302	European structural / semi-solid grade
Silicon (Si) %	7.5–9.5	9.5–11.5	9.6–12.0	9.0–11.0
Copper (Cu) %	3.0–4.0	2.0–3.0	1.5–3.5	≤0.05
Iron (Fe) %	≤1.3	≤1.3	≤1.3	≤0.55 (low-iron variants ≤0.15)
Magnesium (Mg) %	≤0.10	≤0.10	≤0.30	0.20–0.45
Ultimate tensile strength (as-cast)	~324 MPa	~310 MPa	~228–310 MPa	~170–190 MPa as-cast; ~290–330 MPa T6
Yield strength (as-cast)	~160 MPa	~152 MPa	~130–160 MPa	~90–120 MPa as-cast; ~200–240 MPa T6
Elongation	~3.5%	~3.5%	~1–3.5%	~3–10% (T6 ~3–5%)
Thermal conductivity	~96 W/m·K	~96 W/m·K	~96 W/m·K	~150 W/m·K (higher in low-Fe)
Key strength	Best all-round balance	Best fluidity → thinnest walls	Asia’s default; electronics + automotive	Heat-treatable; structural; weldable; best anodizing response
Typical applications	Power tools, gearbox housings, engine brackets, furniture hardware	Thin-wall housings, laptop/phone frames, telecom	5G boxes, motor housings, EV components, appliance frames	EV battery housings, structural chassis nodes, semi-solid castings, heat sinks

A few things worth knowing beyond the table:

• A380 is the North American default for a reason: it casts well, machines well, and has a good strength-to-cost ratio. RapidDirect cites it for power tools, electronic equipment chassis, gearbox cases and engine brackets (https://www.rapiddirect.com/blog/aluminum-die-casting/).
• A383 / ADC12 trades a little strength for fluidity. The extra silicon lets the melt fill long, thin wall sections that A380 would freeze before completing. Xometry explicitly lists “A383.0 (ADC12)” as one alloy (https://www.xometry.com/capabilities/die-casting-services). In Asia, ADC12 is the dominant die casting alloy across automotive and consumer electronics, which makes it the easiest to source and the cheapest to buy globally.
• AlSi10Mg is the odd one out in a good way: low iron, heat-treatable to T6, and significantly better thermal conductivity (~150 W/m·K) than the 380 family (~96 W/m·K). It is the standard alloy for semi-solid metal (SSM) casting and for structural castings that get welded or anodized. If your part is an EV battery tray, a suspension node or a heat sink, AlSi10Mg is likely the spec.
• Other alloys you will meet: A360 (pressure tightness, corrosion resistance, good fluidity — RapidDirect cites it for 5G communication boxes and automotive oil pans), A390 (high hardness and wear resistance at the cost of ductility — engine blocks), and A413 (near-eutectic silicon, best fluidity of the group, used for very thin-walled or complex housings).

Choosing the Right Alloy

A practical decision tree for the 2026 buyer:

• General-purpose structural part, no extreme demands → A380. It is the cheapest, most available, best-documented choice.
• Thin walls (1–2 mm), long flow length, complex geometry → A383 or ADC12. Fluidity wins.
• Sourcing in Asia, high volume, price-sensitive → ADC12. Same family as A383, priced and stocked for volume in China, Japan and Korea.
• Structural, welded, anodized, or heat-treated requirement → AlSi10Mg (low-iron variant for anodizing). Accept a cost premium.
• Pressure-tight application (oil pan, valve body, 5G box) → A360 or a vacuum-assist process on A380/ADC12.
• Wear surfaces (engine blocks, brake components) → A390 — but plan for post-cast machining; it is hard on tooling.

Hot Chamber vs Cold Chamber vs Semi-Solid

Hot chamber (gooseneck) casting. The melting pot is attached to the machine, and a piston draws metal from the pot and injects it through a gooseneck directly into the die. It is fast, cycle-efficient and yields the highest production rates of any die casting method. But the injection mechanism is submerged in molten metal, which limits it to low-melting-point alloys — zinc and magnesium. Molten aluminum would destroy the gooseneck assembly, which is why aluminum die casting is essentially always cold chamber (RapidDirect: https://www.rapiddirect.com/blog/aluminum-die-casting/).

Cold chamber casting. The melt is held in a separate furnace and ladled or dosed into a horizontal shot sleeve in front of the machine. A plunger then drives it into the die. The injection mechanism is never submerged, so the machine survives 660 °C+ aluminum. The cost is slower cycles (each shot must be dosed) and a slightly more variable process — which is precisely why shot-control and dosing automation matter for aluminum.

Semi-solid casting (SSM / rheocasting). The metal is partially solidified — a slurry of solid dendrites in liquid, typically 40–60% solid — before injection. The slurry flows in a laminar rather than turbulent manner, which slashes air entrapment and porosity, and produces mechanical properties close to forged material. RapidDirect lists semi-solid casting as its advanced option “for components with tight tolerances and strong structural requirements” (https://www.rapiddirect.com/services/die-casting/). AlSi10Mg is the canonical semi-solid alloy. Expect higher process cost and a smaller supplier pool — the payoff is porosity-free, heat-treatable, weldable parts.

Die Design: Parting Line, Gating, Ejectors

The die is where the casting’s fate is decided. Three features matter most:

Parting line. The plane where the two die halves meet. It is the site of flash, mismatch and witness lines, and any dimension that crosses it inherits ~±0.1 mm of variability on top of normal tolerance. Rule: put cosmetic surfaces and critical datum features on one die half, keep critical dimensions off the parting line, and specify which side carries the flash.

Gating and runner system. Molten aluminum enters through gates sized and positioned to fill the cavity before freezing. Rules of thumb: gate near thick sections and critical features (they pack first), distribute flow to avoid jetting and turbulence (the source of gas porosity), and expect the gate to leave a vestige that must be trimmed or machined on cosmetic faces. Multiple gates are acceptable when a single gate cannot fill the cavity before solidification — RapidDirect’s design guidance notes you can add more than one injection point if the melt risks freezing before reaching every crevice (https://www.rapiddirect.com/blog/aluminum-die-casting/).

Ejectors and cores. Ejector pins push the part off the core and leave witness marks (small circles or dimples) on the ejector side. Cores form holes and undercuts; side actions (slides) form features perpendicular to the opening direction and add both cost and cycle time. Every hole, thread and undercut should be questioned in DFM: holes under 3 mm diameter are typically drilled after casting rather than cored, because thin core pins can’t survive the aluminum’s temperature and injection pressure — RapidDirect specifies that round holes smaller than 3 mm require secondary drilling (https://www.rapiddirect.com/services/die-casting/).

Die life and steel. Aluminum erodes die steel far faster than zinc. RapidDirect publishes ~100,000 cycles for aluminum and magnesium dies versus ~1,000,000 for zinc (https://www.rapiddirect.com/services/die-casting/). H13 is the standard die steel; the die’s cooling-channel layout determines both cycle time and part quality, and should never be an afterthought.

Tolerances: What Aluminum Die Casting Can Actually Hold

Die casting is a precision process, but it is not machining. Published commercial capability:

• General dimensions: ±0.1 mm — RapidDirect states it can “achieve a tolerance down to ±0.004 in (0.1 mm)” for die-cast aluminum parts (https://www.rapiddirect.com/blog/aluminum-die-casting/).
• Critical features, small parts: ±0.05 mm — achievable on controlled dimensions with steel-safe tooling (machined slightly loose, adjusted in at trial) and a disciplined process.
• Beyond ±0.05 mm: ±0.01 mm only via secondary machining — RapidDirect’s capability table explicitly lists ±0.01 mm “high-precision” parts as requiring secondary machining to meet tolerance (https://www.rapiddirect.com/services/die-casting/).

Tolerance also scales with dimension. A ±0.05 mm band that is routine on a 25 mm boss is expensive on a 250 mm housing wall, because shrink variation and die deflection accumulate with length. Plan your critical callouts accordingly: put tight tolerances on small, local features (bosses, locating pads, bore positions) and keep general tolerances at ±0.1–0.2 mm on large features.

Two process facts that change tolerance expectations:

• Draft is mandatory. Aluminum shrinks onto the core as it solidifies, so every surface perpendicular to the opening direction needs draft to release. RapidDirect specifies a minimum of 0.5° to avoid demolding difficulties (https://www.rapiddirect.com/services/die-casting/); deeper textures and deeper cores need more (1–3°). Draft is not a tolerance — it is a geometry change — but it constrains the dimensions you can hold on tall features.
• Die temperature and cycle stability are the real tolerance controllers. A die that runs at a stable temperature produces stable parts; a die that cycles hot-cold-hot drifts dimensionally. When a buyer sees parts drifting out of band, the fix is usually process control (shot profile, die temperature, spray/dwell time), not the tool.

Wall Thickness: 1–4 mm Is the Sweet Spot

Wall thickness is the single most influential design variable in aluminum die casting — it drives fillability, porosity, cycle time, weight and cost simultaneously.

• Recommended minimum: 1.5 mm for aluminum alloy (RapidDirect: https://www.rapiddirect.com/services/die-casting/). Below that, the melt freezes before filling thin sections reliably and porosity risk climbs.
• Achievable minimum: 0.8 mm — possible in small areas with high-fluidity alloys (A383/ADC12) and aggressive process control. RapidDirect’s blog notes “less than 1.5 thickness is achievable” with modern machines (https://www.rapiddirect.com/blog/aluminum-die-casting/).
• Typical design range: 1–4 mm. Most commercial castings live here — thick enough to fill reliably, thin enough to save metal and cycle time.
• Wall ratio rule: keep adjacent walls within 1:3 — RapidDirect’s guidance is to keep the wall thickness ratio within 1:3 to avoid uneven filling (https://www.rapiddirect.com/services/die-casting/). A 1 mm wall feeding a 6 mm boss will starve the thin section or sink the thick one.

Uniformity beats thinness. A casting with consistent 2 mm walls will fill cleaner, cool more evenly and hold tolerance better than one with 1.2 mm walls in some places and 3.5 mm in others. When you need local strength, add ribs (at 0.6–1.0× wall thickness) instead of thickening the wall.

Surface Finishes: As-Cast to Anodized

Aluminum die castings come off the press with a smooth, fine-grained surface — often good enough for functional parts as-is. But two realities push most buyers into finishing: aluminum does not self-passivate as reliably as zinc, and Xometry states plainly that aluminum parts must be coated to achieve corrosion resistance (https://www.xometry.com/capabilities/die-casting-services), and cosmetics matter for consumer-facing products.

Finish	What it does	Notes
As-cast	Lowest cost; functional surface	Expect gate vestige, ejector marks, 16–64 µin Ra range (zinc per Xometry; aluminum similar)
Bead blasting	Matte, uniform texture; hides minor surface defects	Common prep step before coating
Powder coating	Durable, ding/scratch-resistant, wide color range	RapidDirect’s most-cited cosmetic option (https://www.rapiddirect.com/blog/aluminum-die-casting/)
Anodizing (Type II / III)	Corrosion-resistant, wear-resistant oxide layer; non-conductive	Xometry: die-cast surface does not facilitate a cosmetic anodizing finish — functional, not show-grade (https://www.xometry.com/capabilities/die-casting-services)
Chem film (Alodine)	Thin conductive conversion coating	Electrically conductive — choose this over anodize when grounding/EMI matters (RapidDirect)
Electroplating	Decorative chrome/nickel/copper layers	Doable with proper prep (zincate + copper strike); harder than plating zinc

Three practical rules: (1) if the part needs electrical conductivity, avoid anodizing — the oxide layer is insulating (both RapidDirect and Xometry flag this); (2) if you want a show-grade cosmetic anodize, either specify a low-iron alloy (AlSi10Mg low-Fe) and accept some surface variation, or machine the visible faces; (3) most finishing defects trace back to porosity at the surface — a casting with subsurface porosity will blister under powder coat and bloom under anodize.

Porosity: The Casting’s Signature Defect and How to Beat It

Porosity is the defect buyers fear most, and it is structural to high-pressure die casting: the melt enters the cavity as a turbulent spray, trapping air (gas porosity), and the alloy shrinks ~3–6% by volume on solidification, which thick sections can’t feed (shrinkage porosity).

What porosity actually does:

• Leaks pressure in fluid-handling parts (oil pans, valve bodies, compressor housings).
• Blisters under paint, powder coat or anodize.
• Opens up under machining — a seemingly solid boss machines into a sponge.
• Cracks under fatigue or pressure testing.

The countermeasures, in order of effectiveness:

1. Design it out — uniform walls, no isolated thick sections, generous radii, gates near thick sections. The cheapest porosity fix is a better part design.
2. Process control — optimized shot profile (slow-fast-slow), high intensification pressure, die temperature control. A disciplined process is what separates a 5% scrap shop from a 0.5% shop.
3. Vacuum-assisted die casting — evacuate the cavity before injection to remove the air that becomes gas porosity. The standard upgrade for pressure-tight and structural castings.
4. Semi-solid casting — laminar fill, essentially porosity-free; the spec for structural, heat-treated parts.
5. Impregnation — vacuum-impregnate the casting with a sealing resin to close interconnected porosity. A common, cost-effective fix for pressure-tight parts that are otherwise acceptable.
6. Accept and verify — specify the porosity standard (e.g., X-ray or sectioning criteria) up front, so “acceptable porosity” is a written agreement, not a surprise.

Cost Drivers: Where the Money Goes

Die casting cost splits into two very different curves — tooling and per-part.

Tooling (die cost). RapidDirect publishes a range of USD 7,000–75,000 for die casting tooling, depending on die size, cavity count, part complexity and whether hollow/complex profiles are involved (https://www.rapiddirect.com/blog/aluminum-die-casting/). The die is a one-time investment that amortizes over the production run — which is why die casting only becomes economical at volume.

Per-part cost is driven by:

• Material — aluminum alloy price plus melt losses (~5–10% oxidation and dross on remelt).
• Cycle time — seconds per shot, driven by wall thickness (cooling time dominates) and die cooling efficiency.
• Secondary operations — trimming, CNC machining of critical features (the ±0.01 mm features), tapping, finishing. This is where cost overruns hide; each machined feature adds handling and a fixture.
• Finishing — powder coat, anodize, plating, in that order of typical cost.
• Volume — RapidDirect notes the process “becomes more cost-effective when you go for large volume production,” and its service page cites a 500–1000 piece MOQ band (https://www.rapiddirect.com/services/die-casting/). Below that, CNC machining or 3D printing usually wins on total cost.

Rule of thumb for sourcing: tooling drives the decision to die cast; per-part price drives the volume decision. If the tooling amortization doesn’t pencil out against machining at your annual volume, die casting is the wrong process — no matter how good the quote looks.

Industry Applications: Automotive, Electronics, Telecom

Aluminum die casting’s property mix — light, strong, conductive, heat-dissipating, EMI-shielding — makes it the default for three sectors in 2026:

• Automotive — engine blocks (A390), gearbox cases, oil pans (A360), brackets, motor housings for EVs, and increasingly battery trays and structural nodes (AlSi10Mg). The automotive angle is weight: every kilogram saved is range or fuel economy. RapidDirect flags automotive among the top application sectors, and notes the global aluminum casting market at USD 50.5 billion in 2019 with ~6.4% CAGR growth expected (https://www.rapiddirect.com/blog/aluminum-die-casting/).
• Electronics — chassis for electronic equipment, power tool housings, laptop/phone frames (A383/ADC12 thin-wall work), motor housings and heat sinks. RFI/EMI shielding comes free with a conductive metal housing.
• Telecom/5G — the canonical modern application: 5G base-station boxes need thermal management, weather resistance and dimensional stability. RapidDirect specifically cites A360 for 5G communication boxes and automobile controller shells (https://www.rapiddirect.com/blog/aluminum-die-casting/).
• Other consistent buyers — appliances, furniture hardware, lighting fixtures, industrial equipment, and anything outdoor that needs corrosion resistance plus impact strength.

Aluminum Die Casting vs Zinc Die Casting

Zinc is the other commercial die casting metal, and the choice between them is usually clear once you know the part:

Factor	Aluminum	Zinc
Melting point / process	~660 °C; cold chamber only	~390–420 °C; hot chamber — fastest cycles (Xometry)
Wall thickness	1.5 mm recommended min	Down to ~0.8 mm (RapidDirect)
Tolerance	±0.1 mm typical	Tighter — zinc holds “tight tolerances” more easily (Xometry: https://www.xometry.com/capabilities/die-casting-services)
Strength-to-weight	Excellent — the reason to choose aluminum	Heavier; strong and ductile
Surface	Needs coating for corrosion	Self-passivating; easily plated; as-cast 16–64 µin Ra (Xometry)
Die life	~100,000 cycles (RapidDirect)	~1,000,000 cycles (RapidDirect)
Typical parts	Structural, heat-dissipating, large housings	Small detailed parts, handles, decorative hardware, electrical terminals

The practical answer: zinc when the part is small, detailed, needs the tightest tolerance or thinnest walls, and doesn’t care about weight; aluminum when the part is large, structural, heat-bearing, or weight-sensitive. For a 30 g connector housing, zinc is usually right. For a 2 kg motor housing, aluminum, unambiguously.

Aluminum Die Casting vs Injection Molding

The metal-vs-plastic decision deserves its own treatment — we maintain a full comparison in our die casting vs injection molding guide. The short version:

• Choose injection molding when the part carries no load, sees no heat, needs electrical insulation, and volume is high enough to amortize plastic tooling ($5k–50k typically). Plastics win on cost, color, and design freedom for complex organic shapes.
• Choose aluminum die casting when the part must carry load, shed heat, shield EMI, survive heat or UV, or feel premium. Aluminum wins on strength, thermal/electrical performance and durability — at higher tooling cost ($7k–75k) and heavier weight.
• The crossover case — a plastic part that keeps failing in the field — is one of the most common reasons buyers come to us for a die casting quote.

DFM Checklist for Aluminum Die Castings

Run this list before you send a part for quoting:

• Wall thickness: uniform 1–4 mm; minimum 1.5 mm unless high-fluidity alloy and aggressive process; keep adjacent walls within 1:3.
• Ribs and bosses: rib thickness 0.6–1.0× wall; boss diameter ≥ 2× hole diameter; add gussets to tall bosses.
• Draft: minimum 0.5° on all vertical faces; 1–3° on textured or deep features; more draft on the core side (shrinkage grabs it).
• Holes: ≥ 3 mm to core; smaller holes drilled after casting; threads always machined, never cast.
• Radii: ≥ 0.5 mm at internal corners; avoid sharp re-entrant corners that trap flow and stress.
• Critical dimensions: keep off the parting line; small, local features only; specify ±0.1 mm general, ±0.05 mm critical, ±0.01 mm machined.
• Parting line and ejector marks: know where they land; move them off cosmetic faces.
• Porosity-sensitive areas: no isolated thick sections; gates near thick sections; specify vacuum casting or impregnation for pressure-tight parts.
• Finish: decide as-cast vs coated before quoting; aluminum needs coating for corrosion; anodize is non-conductive and not show-grade on die-cast surfaces.
• Secondary operations: list every machined feature, tapped hole and surface requirement in the RFQ — unlisted machining is where budgets die.

How We Approach Die Casting Programs

MOLDITQUICK (Dongguan Guohong Precision, China) runs die casting as one of our in-house processes alongside injection molding, mold making, CNC machining and stamping — which changes the sourcing conversation. Instead of coordinating a foundry, a machine shop and a finisher separately, a die casting program can live under one roof and one quality system: IATF 16949 (automotive), ISO 13485 (medical) and ISO 9001. Our plant spans 10,000 m² with 280 people, including 20 Aida presses for stamping and finishing-adjacent work, 18+3 Sodick injection molding machines (for the plastic half of hybrid metal-plastic products), 9+4 wire EDM machines for in-house tooling, and full DFM review before any quote. Every program starts with a DFM pass and a written tolerance-feasibility review — the same checklist above — and ships globally with first-article inspection documentation. See our die casting service for capability details, or skip straight to uploading a part for review.

Frequently Asked Questions

1. What is the difference between die casting and sand casting? Die casting injects molten metal into a steel die at high pressure — fast cycles, near-net-shape parts, thin walls (1 mm range), tight tolerance (±0.1 mm), but high tooling cost. Sand casting pours metal into a sand mold under gravity — low tooling cost, thick walls (typically 4 mm+), looser tolerance, and porous, machined surfaces. Die casting wins at volume; sand casting wins for one-off and very large parts.

2. Which aluminum die casting alloy is best? A380 for general-purpose strength and cost; A383/ADC12 for thin walls and Asia sourcing; AlSi10Mg for structural, welded, anodized or heat-treated parts; A360 for pressure-tight applications; A390 for wear surfaces.

3. What tolerance can aluminum die casting hold? ±0.1 mm on general dimensions; ±0.05 mm on small critical features with steel-safe tooling and process control; ±0.01 mm only via secondary machining (RapidDirect: https://www.rapiddirect.com/services/die-casting/).

4. What is the minimum wall thickness for aluminum die casting? 1.5 mm recommended minimum (RapidDirect); ~0.8 mm achievable in small areas with high-fluidity alloys like ADC12; typical design range 1–4 mm with adjacent walls within a 1:3 ratio.

5. Why is aluminum die cast on cold-chamber machines? The injection mechanism of a hot-chamber machine sits submerged in molten metal — aluminum’s ~660 °C melt would destroy it. Hot chamber is for low-melting-point zinc and magnesium (RapidDirect).

6. What causes porosity in die castings and how do you prevent it? Turbulent fill traps air (gas porosity) and solidification shrinkage creates voids in thick sections. Countermeasures: uniform wall design, optimized shot profile, vacuum-assisted casting, semi-solid casting, and resin impregnation for pressure-tight parts.

7. Can aluminum die castings be anodized? Yes — Type II and Type III anodizing are standard. But the die-cast surface does not produce a show-grade cosmetic anodize (Xometry); specify a low-iron alloy and/or machine visible faces for cosmetic results. Anodized surfaces are non-conductive.

8. How much does a die casting die cost? Roughly USD 7,000–75,000, driven by die size, cavity count, complexity and moving actions (RapidDirect: https://www.rapiddirect.com/blog/aluminum-die-casting/).

9. How long does a die casting die last? About 100,000 cycles for aluminum and magnesium dies; about 1,000,000 cycles for zinc dies (RapidDirect).

10. Die casting vs injection molding — which should I choose? Metal when the part must carry load, shed heat, shield EMI or survive harsh environments; plastic when it must be light, insulating, low-cost and organically shaped. See our full die casting vs injection molding comparison.

11. Is die casting cheaper than CNC machining for aluminum? At volume, yes — near-net-shape casting beats cutting away 60–80% of a billet, and RapidDirect cites up to 30% price reduction on their die cast programs. For low volume (<500–1,000 pcs), machining or 3D printing wins because the die amortization doesn’t pencil out.

12. What is the typical MOQ for die casting? RapidDirect’s published band is 500–1,000 pieces (https://www.rapiddirect.com/services/die-casting/). Lower volumes are possible with simplified tooling, but die casting is fundamentally a volume process.

13. Can die-cast aluminum be welded or plated? Yes. Welding requires low-iron alloy (AlSi10Mg casts cleanly; A380 welds poorly due to high iron/copper). Plating is possible with proper pre-treatment (zincate immersion plus copper strike) but is harder and less common than plating zinc — zinc is the easier plating substrate.

14. How long does a die casting project take? RapidDirect publishes a 20–25 day lead time for production (https://www.rapiddirect.com/services/die-casting/). Tooling design and build typically adds 4–8 weeks before that, plus T1 sample approval — Xometry’s workflow sends T1 samples for approval before production begins (https://www.xometry.com/capabilities/die-casting-services).

Sources

• RapidDirect — Aluminum Die Casting: A Comprehensive Guide: https://www.rapiddirect.com/blog/aluminum-die-casting/
• RapidDirect — Custom Die Casting Services (capability table): https://www.rapiddirect.com/services/die-casting/
• Xometry — Custom Die Casting Services: https://www.xometry.com/capabilities/die-casting-services
• Xometry — Die Casting: Definition, Types, Materials, Applications: https://www.xometry.com/resources/casting/die-casting
• Alloy composition and mechanical values: typical published values per NADCA standards and alloy supplier datasheets (A380.0, A383.0, ADC12 per JIS H 5302, AlSi10Mg per EN 1706); exact values vary by heat and foundry practice.

Related resources

• Die casting service — our in-house die casting capability
• Die casting vs injection molding — when to pick metal, when to pick plastic
• DFM checklist for molded parts — wall, draft and tolerance rules that transfer to castings
• CNC machining service — secondary machining for ±0.01 mm features
• Surface finishing — powder coat, anodize and plating options
• Materials — alloy and plastic selection hub
• Get a quote — upload your part for a DFM review