Consumer Electronics: A 0.3 mm Thin-Wall Housing in One Extrusion Route
A 3C accessory brand had a housing that was being milled from solid: accurate, but slow and expensive for the volume they were planning. The wall was the whole argument — at 0.3 mm, extrusion is the only route that makes the part at a sensible cost, and machining is the only thing that keeps it in tolerance.
- Industry
- Consumer electronics
- Process
- Extrusion + staged CNC + bead blast anodize
- Alloy
- 6063-T6
- Key spec
- 0.3 mm wall, ±0.02 mm capability
What the customer needed
The customer was machining the housing from a solid billet. The part worked, but most of the billet became chips, and the cycle time made the unit cost hard to defend as volumes grew.
The constraint that decided the route was the wall: 0.3 mm, which the design needed for the product to feel right in the hand. At that thickness, milling from solid means removing almost everything and then fighting the deflection of what is left. Extruding the wall instead means the metal is formed at the right thickness and machining only has to preserve it.
The secondary constraint was appearance: a bead-blast anodized matte on a surface thin enough that a handling dent would be visible in retail.
Constraints that decided the part
- Wall thickness 0.3 mm, ±0.02 mm capability
- One-piece body — no glued or welded sub-assembly
- Bead blast anodized finish with no polishing marks
- Batch cost below the equivalent solid-billet route
- Alloy 6063-T6 for stiffness at thin wall
How the part was made
The same route we would propose today, in the order it actually runs.
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Section design
The wall, the internal rails and the end-cap step were combined in one section, so the part left the die already at 0.3 mm rather than being cut down to it.
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Die and extrusion
The die was cut in 4–5 days with the bearing length set for a thin wall, and the profile was run and aged to T6 for stiffness.
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Staged CNC
Roughing, stress relief, then finishing in a fixture cut from the production profile. Light, evenly distributed clamping stops the wall from collapsing inward during the cut.
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Bead blast and anodize
180# bead blast without polishing, then anodizing in the approved colour. Blasting also hides the fine handling marks that a polished surface would show.
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Inspect and pack
Wall thickness measured after stress relief, appearance checked against the retained chip, and parts packed to avoid contact between thin walls.
The numbers the part had to hold
These are the tolerances and process values that governed the job. They come from our capability, not from a customer specification we cannot publish.
| Parameter | Value | Why it mattered |
|---|---|---|
| Wall thickness | 0.3 mm | The design constraint that made the route necessary |
| Wall thickness capability | ±0.02 mm | Directly affects how the part feels and how the cap fits |
| Profile cross-section | ±0.05 mm | Sets the blank the machining starts from |
| Machined fits | ±0.01 mm | Cap step and port cut-outs |
| Alloy and temper | 6063-T6 | Stiffness at 0.3 mm without brittleness |
| Batch cost vs. solid billet | 30–50% lower | The reason the route changed |
The part of this job that nearly went wrong
This is the section worth reading. Every program has one problem that decides whether the parts come out right, and it is usually not the one on the drawing.
Clamping force collapsing the wall
A 0.3 mm wall behaves like a shell, not a block. Clamp it the way you would clamp a billet and it deforms under the fixture, springs back after the cut, and the finished part is oval.
The risk
Parts that pass inspection in the fixture and fail when the customer measures them free-standing — a failure that looks like a measurement dispute rather than a process problem.
What we changed
The fixture was cut from the production profile so the wall is supported along its length, with light clamping distributed over as much area as possible. Cuts are staged with stress relief between roughing and finishing, and the wall is measured after the part has relaxed.
Appearance on a surface too thin to rework
A dent or a scratch on a 0.3 mm wall cannot be polished out — polishing would remove a measurable fraction of the wall. That rules out the usual cosmetic rework.
The risk
A cosmetic rejection rate that cannot be recovered by rework, only by scrap.
What we changed
The matte bead-blast finish was chosen for the look and kept for the process: it diffuses fine handling marks where a polished surface would highlight them. Parts are handled in protective sleeves between operations, and the finish is approved on a chip before the run.
0.3 mm wall, one piece, at a batch cost solid billet could not reach
The housing is now a single 6063-T6 extrusion with the wall formed in the die and the fits machined to ±0.01 mm. Wall thickness holds ±0.02 mm in production and the finish is a bead-blast anodized matte with no polishing step.
Compared with the previous machined-from-solid design, the batch cost is 30–50% lower because roughly 90% of the material never becomes chips. The part that changed was not the design — it was the route to it.
We do not publish a yield figure for this part. What we will say is that the wall is measured after stress relief, and a part that does not hold it does not ship.
Common questions about this program
The questions this case generates from engineers and sourcing teams.
Is 0.3 mm a safe wall for a production part?
Yes, for a housing where the wall closes the body and carries no structural load. A wall carrying load should be 0.6 mm or more. We ask what the wall does before agreeing to 0.3 mm, because the answer changes the process.
Can a 0.3 mm wall be anodized without distortion?
Yes. The anodic layer builds on the surface rather than removing material, so it does not thin the wall. What it does change is appearance, which is why the texture and colour are approved on a chip from the same alloy and blast.
How much cheaper is this than milling from solid?
On this class of housing we quote 30–50% lower batch cost than machining from solid billet. The range depends on how much of the geometry the die can carry — the more the profile does, the larger the saving.
Have a Thin-Wall Housing Being Milled From Solid?
Send the drawing with the wall thickness and the annual quantity. We will tell you whether the section can carry that wall and what the route change is worth.
What to send
- 2D drawing or 3D model (STEP, IGES, DWG, DXF, PDF)
- Alloy and temper
- Surface finish and color
- Estimated annual quantity
Client names are withheld under confidentiality. Figures reflect our verified process capability.