Die cast aluminum for consumer electronics covers thin-wall chassis and mid-frames, display bezels, heat spreaders, camera and optical housings, and set-top and networking enclosures. CharMax Precision casts these in ADC12 at 1.0 to 1.5 mm wall thickness on 160 to 1,250 ton machines, finishing them to a signed cosmetic standard while the aluminum itself provides the EMI shielding a plastic housing needs coatings to achieve.
Die cast aluminum for consumer electronics covers thin-wall chassis and mid-frames, display bezels, heat spreaders, camera and optical housings, and set-top and networking enclosures. CharMax Precision casts these in ADC12 at 1.0 to 1.5 mm wall thickness on 160 to 1,250 ton machines, finishing them to a signed cosmetic standard while the aluminum itself provides the EMI shielding a plastic housing needs coatings to achieve.
Electronics programmes are judged on two things a mechanical drawing rarely captures well: how the part looks, and whether it still looks that way after 200,000 pieces. A flow mark on a hidden rib is irrelevant; the same mark on a visible bezel is a rejected lot. Most of the engineering effort on these parts goes into where metal enters the cavity, where ejector pins land, where the parting line runs, and how the coating system is controlled batch to batch.
The commercial shape is different too. Product lives are short — often 12 to 24 months — so tooling has to amortise over the whole programme rather than over years, and the ramp is steep. That pushes towards multi-cavity dies, automated extraction and a finishing process that can be repeated consistently at rate rather than tuned part by part.
| Typical alloys | ADC12 for thin wall and long flow paths, A380 where the part is heavily machined |
|---|---|
| Typical part weight | 20 g to 2 kg per casting |
| Typical wall thickness | 1.5 mm typical, 1.0 mm achievable on small parts with short flow paths |
| Machine range | 160 to 1,250 tons cold chamber |
| Typical annual volume | 20,000 to 500,000+ parts per model |
| As-cast tolerance | ±0.1 mm for the first 25 mm |
| Machined tolerance | ±0.02 mm on thermal interfaces, bores and fit features |
| As-cast surface | Ra 1.6 to 3.2 µm before finishing |
| Cosmetic finishes | Powder coat, wet paint, mechanical polishing, chromate conversion |
| Cosmetic control | Signed boundary samples, zoned drawing, ΔE and gloss limits per lot |
| Compliance | RoHS and REACH declarations, alloy chemistry and coating substance data |
| Lead times | 25 to 40 days tooling, 15 to 25 days production |
Electronics enquiries are usually late-stage. The PCB is fixed, the industrial design is approved, the launch date is public, and the mechanical part has to fit inside all three. The constraints below are the ones that decide whether a programme runs smoothly.
A drawing that says the surface must be free of visible defects is unusable at production rate. Without a zoned cosmetic map, a defined viewing distance and lighting level, and physically signed boundary samples, every lot becomes an argument between two people looking at the same part under different lamps.
Chassis and mid-frames are asked to be 1.0 to 1.5 mm for weight and internal volume, while still resisting the torsional flex that cracks solder joints and creates display mura. The wall cannot simply be thickened, because thickness on a cosmetic part shows as sink marks opposite every boss.
The casting is usually the datum for the whole assembly, so boss heights, standoff flatness and snap-feature positions have to hold against parts made by a different process in a different factory. Coating thickness of 60 to 100 µm is enough to close an interference fit that worked on bare parts.
Aluminum shields inherently, but only if the ground path is continuous. Powder coat over a grounding pad is an insulator, a gasket land with a coating step will leak at high frequency, and a seam that is dimensionally fine can still fail an emissions scan. These are drawing decisions that need to be made before tooling.
As devices get thinner the chassis becomes the heat sink. That means a flat machined interface for a thermal pad or paste, a defined path from the die or shield can to the outer wall, and a coating that does not sit between the two.
A 12 to 24 month product has to amortise tooling within its lifetime volume, which changes the cavity-count arithmetic. Getting the die right at T1 matters more here than in any other industry we serve, because a six-week tooling correction is a meaningful fraction of the sales window.
Compared with a plastic enclosure, an aluminum casting brings shielding, stiffness and a thermal path in one part. A plastic housing that needs to pass emissions testing requires conductive paint, foil or plating, all of which add process steps, add cost, and can be scratched or masked incorrectly. The casting is conductive throughout.
Compared with sheet metal, casting removes the assembly. Bosses, standoffs, gasket grooves, cable channels, antenna pockets, fastener bosses and heat-spreading fins all come out of the die in one operation, so a five-piece bracket-and-shield assembly becomes one part with one set of datums. ADC12 fills the 1.0 to 1.5 mm walls this requires because its higher silicon content gives better fluidity through long, thin flow paths than A380.
Compared with machining from billet, the difference is simply volume economics. Above roughly 20,000 pieces a year the die amortises to a small fraction of the piece price, and the casting reproduces detail — textures, thin ribs, fine bosses — that would take a long cycle to mill.
| Component | Alloy | Key requirement | Typical finish |
|---|---|---|---|
| Device chassis and mid-frame | ADC12 | 1.0 to 1.5 mm wall, torsional stiffness, boss flatness for the PCB stack | Shot blast plus wet paint, grounding pads masked |
| Display bezel and front frame | ADC12 | Class A cosmetic face, no flow marks or sink on the visible surface | Polished then wet paint or powder coat to a ΔE limit |
| Heat spreader and thermal plate | A360 or A413 | Thermal conductivity, machined flat interface for pad or paste | Chromate conversion, interface masked and left bare |
| Camera and optical module housing | ADC12 | Dimensional stability of the lens mount, internal light traps, thin wall | Matte black powder coat or paint, internal surfaces included |
| Set-top box and networking enclosure | ADC12 | EMI shielding continuity, ventilation geometry, cast standoffs | Powder coat with masked ground contacts |
| Speaker body and acoustic baffle | A380 | Mass and damping to control resonance, sealed volume, flat gasket land | Textured powder coat |
| Projector and AV chassis | A380 | Rigid optical mounting datums, heat path from the light engine | Matte black internal coating, machined optical pads |
| Drone frame and gimbal housing | ADC12 | Minimum mass, stiffness against vibration, motor mounting accuracy | Chromate conversion or thin powder coat |
| Charger, adapter and dock body | ADC12 | Thin wall, creepage and clearance geometry, cosmetic outer surface | Powder coat to the brand colour |
ADC12 carries 9.6 to 12% silicon, which gives the fluidity needed to fill a 1.0 to 1.5 mm wall over a long flow path before the metal freezes. A380 is used where the part is heavily machined, since it machines better and holds a cleaner thread. Where the part is primarily a heat spreader, A360 or A413 are specified for their higher thermal conductivity.
Metal entering the cavity leaves a signature: flow lines, a slightly different texture, occasional cold-shut witness. Those belong on a surface that is hidden in the assembly. Gate position, overflow position and vent layout are therefore decided from the cosmetic zone map rather than from fill convenience alone, which is why we ask for the zone map before the die is designed.
Ejector pin witness marks are unavoidable; where they land is a choice. So is the parting line, which shows as a fine seam and is best placed on a design break line, an edge radius or a shadow line the industrial designer already drew. Agreeing both at DFM avoids a cosmetic dispute that no amount of polishing will fix later.
Every boss, rib and thick section on the back of a cosmetic wall pulls a shallow depression on the visible side as it solidifies. Keeping ribs at 60 to 80% of the wall, coring out heavy bosses, and blending sections with generous radii prevents it. Sanding a sink mark out of a production part is slow, inconsistent and shows through paint.
Powder coat builds 60 to 100 µm per surface and wet paint 25 to 40 µm, which is enough to close a clearance fit, change a boss height or interfere with a snap feature. Fits, gasket lands and mating faces are dimensioned in the coated condition, and features that must stay bare are masked or machined after coating.
The high silicon that makes the alloy castable makes the anodic film darker, greyer and less uniform than on wrought aluminum, and it will not match an anodized extrusion or a machined unibody part. Where a bare anodized metal appearance is central to the industrial design, machining from wrought aluminum is the honest recommendation and our sister CNC operation can quote it. Where the surface is painted, casting is the better process.
Both of these functions are free with an aluminum casting and easy to lose in finishing. Aluminum conducts heat at 96 to 121 W/m·K and conducts electricity well enough to act as a shield and a ground plane, but a 60 to 100 µm coating over the wrong face defeats either one.
For thermal performance we machine the interface that meets a thermal pad or paste so it is flat and bare, keep the conduction path short and unbroken between that interface and the outer wall or fin field, and cast fins where surface area is needed. Fin geometry that would be slow to machine — tapered, closely spaced, integrated into a housing wall — is straightforward in a die.
For EMI we treat continuity as a dimensioned requirement. Grounding pads and gasket lands are masked during coating or machined clean afterwards, seams are designed with adequate overlap and fastener spacing rather than relying on a nominal joint, and any conductive gasket channel is cast in so the gasket seats consistently instead of following a hand-applied bead.
Cosmetic quality only becomes manageable when it is written down as measurable limits and physical samples. We ask for a zoned drawing that marks which surfaces are visible in the finished product, then agree defect limits per zone, sign boundary samples for accept and reject, and fix the inspection conditions so results are repeatable between our line and your incoming inspection.
| Control | Typical specification | Purpose |
|---|---|---|
| Zone map | Zone A visible in use, Zone B visible on handling, Zone C hidden in assembly | Concentrates cost on surfaces the user actually sees |
| Viewing conditions | 500 mm distance, 800 to 1,000 lux diffuse light, 10 seconds per surface | Makes two inspectors reach the same verdict |
| Boundary samples | Signed accept and reject parts held at both sites, replaced yearly | Removes argument over borderline lots |
| Colour | ΔE ≤ 1.0 against the signed master under D65 | Keeps lots matching each other and adjacent plastic parts |
| Gloss | 60° gloss within ±5 GU of master | Prevents visible sheen differences across an assembly |
| Coating thickness | Powder 60 to 100 µm, wet paint 25 to 40 µm, measured per lot | Protects fits, gasket lands and grounding continuity |
| Adhesion | Cross-hatch tape test to ASTM D3359, class 4B or better | Verifies pretreatment and cure, not just appearance |
| Sampling | ANSI or ISO 2859-1 general inspection level II, AQL agreed per zone | Defines the statistical basis for lot release |
| Parting line and pin marks | Position agreed on the drawing, height limit stated | Turns an unavoidable feature into a specified one |
Cosmetic limits are agreed before tooling. Adding a Class A requirement to a surface after the die is cut usually means moving a gate or an ejector pin, which is a tooling change rather than an inspection change.
Alongside the cosmetic controls, electronics programmes need dimensional evidence on the features that drive assembly and a compliance package that satisfies your regulatory and customer audits.
Real parts we have manufactured that involved this capability.
Yes, on a painted or powder coated surface, provided the cosmetic zones are agreed before tooling. The coating covers the minor texture variation inherent to an as-cast surface, and the underlying casting is prepared by shot blasting, vibratory finishing or mechanical polishing first. What die casting cannot deliver is a Class A bare metal surface: an as-cast face shows flow lines and occasional porosity blush, and anodizing high-silicon alloy produces a mottled grey film. If the design calls for bare anodized metal, machining from wrought aluminum is the right process.
1.5 mm is the routine minimum and 1.0 mm is achievable on small parts with short flow paths in ADC12. The real constraint is flow length rather than thickness alone, because the metal has to reach the far end of the wall before it freezes: a 1.2 mm wall running 40 mm from the gate is straightforward, the same wall running 200 mm is not. Send the 3D model and our flow simulation will confirm whether the geometry fills, or show where a local thickening or a second gate is needed.
Generally yes, because the shielding is the material rather than a coating applied to it. A metallised plastic shell depends on a conductive layer that can be thin, scratched, masked incorrectly or degraded over time, while a casting is conductive through its full section. The caveat is that shielding depends on continuity: grounding pads must be masked during coating, gasket lands must be flat and bare, and seams need adequate overlap and fastener spacing. Those details are designed into the casting rather than added afterwards.
By replacing subjective language with three concrete things: a zoned drawing that states which surfaces are visible in use, physically signed accept and reject boundary samples held at both sites, and fixed inspection conditions covering viewing distance, light level and time per surface. On top of that we agree ΔE and gloss limits against a master, a coating thickness range, and an AQL sampling plan per zone. Every one of those is agreed before the die is cut.
Yes, as long as the tooling amortises across lifetime volume rather than annual volume. A die survives 80,000 to 150,000 shots, so a short-life product typically consumes only part of the tool's capacity, and tooling at 3,000 to 25,000 USD spread across 100,000 pieces adds a few cents per part. The bigger risk in a short programme is a tooling correction after T1 samples, which is why the DFM review, cosmetic zone map and gate placement are settled before steel is cut.
Yes, within a stated tolerance. We work to a signed colour master with a ΔE limit, typically ΔE ≤ 1.0 measured under D65, plus a 60° gloss window of ±5 GU, and record both per finishing batch. Matching an adjacent plastic part is more demanding because the substrate and coating differ, so the practical approach is to hold both parts to the same master rather than matching one part to the other, and to review a physical assembly sample before release.
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.
Send your 3D model, a zoned drawing marking the visible surfaces, and the annual volume. You will get piece pricing, tooling cost with cavity options, a finishing recommendation and a written DFM report covering wall thickness, gate placement and where the parting line should run.
