Pockets, recesses and internal cavities cut into 6061, 7075 and ADC12 with wall thickness down to 0.8 mm. We hold ±0.005 mm on critical bores and keep cavity floors flat so seals seat on the first assembly.
Most cavity parts that fail are not cut badly. They are drawn or set up in a way that cannot repeat.
A 1.0 mm wall between two pockets looks fine in CAD. In the vise it deflects, the cutter pushes it out, and the wall measures 0.15 mm out of print once unclamped. The fix is in the fixture and the roughing sequence, not in a slower feed.
When tool length reaches five times diameter, a long end mill rings. The cavity floor comes out with visible steps and Ra climbs past 3.2 μm. A sealing surface like that needs hand polishing or a second setup, and both cost you days.
A 0.5 mm internal corner in a 40 mm deep pocket means a 1 mm cutter, which cannot clear chips. Tools snap, and the part is scrapped. We flag this at DFM instead of finding out on the machine.
Cavity machined in op 1, bolt pattern in op 2. If the datum moves between setups, the cover will not line up and the gasket leaks. Position errors of 0.05 mm are enough to lose a build.
Cavity work is a fixturing problem before it is a cutting problem.
On a 3-axis machine, a deep aluminum cavity forces you to use a long tool with a small stepover. On our 16 simultaneous 5-axis centers, the table tilts and the tool stays short. Short tools deflect less, so the wall stays parallel and the floor stays flat.
We rough with high-feed tooling to clear material fast, leave 0.3 mm on walls, then finish with a relieved cutter to avoid rubbing. For a 6061 housing with 1.2 mm walls, that sequence holds wall thickness to ±0.03 mm and cavity depth to ±0.02 mm without a second setup.
6061-T6 machines cleanly, takes anodizing evenly and is the default for cavity housings. 7075 gives you about twice the yield strength, which matters when a thin wall has to resist internal pressure, but it is harder to anodize to a consistent color. 2024 cuts well and is common in aerospace cavity work, though it needs a protective finish.
For die-cast housings that need secondary machining, ADC12 is what we cut most. Castings arrive with 0.4-0.8 mm of skin and porosity near the surface, so we take a cleanup pass before the finishing cuts. That avoids pulling a chunk of porous material out of a sealing face.
Match the cavity proportions to the process before you commit to a design.
| Cavity type | Typical route | What to watch |
|---|---|---|
| Open pocket, depth < 3× width | 3-axis milling | Standard vise work. Cheapest route. |
| Deep pocket, depth 3-5× width | 5-axis with tilted tool | Tool overhang drives chatter risk. |
| Multiple faces with cavities | 5-axis, one setup | Datum choice decides bolt hole alignment. |
| Thin wall 0.8-1.5 mm | 5-axis, rough then finish | Clamping pressure must be controlled. |
| Round cavity in a turned body | Mill-turn center | Concentricity held in one spindle. |
| Cavity plus flat cover face | 5-axis, single setup | Face runout under 0.02 mm. |
Cavity work rarely stops at one process. These are the ones we run in-house.
Sixteen simultaneous 5-axis centers for deep pockets, angled faces and cavities with features on more than one side. Short tools, one setup, tight position control.
Twelve four-axis mills for parts that need rotation but not full contouring. Good fit for cylindrical housings with pockets around the bore.
Twenty-seven three-axis machines handle open pockets, plates and covers where a single face carries all the cavity depth.
Mill-turn centers cut round cavities and milled features in the same spindle, so concentricity does not depend on a second op.
One-off cavity parts for fit checks and flow testing, machined from the same alloy as production so the validation means something.
Anodizing, hardcoat, bead blasting and laser marking. We mask sealing faces and bores so the finish does not change fit.
| Item | Range | Included by default |
|---|---|---|
| Maximum part size | 4,000 × 400 × 150 mm | Larger sizes quoted case by case |
| Standard work envelope | 750 × 1,150 × 550 mm | Most housing and cover work |
| Cavity tolerance | ±0.005 mm | On critical bores and sealing faces |
| Surface finish | Ra 0.8-1.6 μm | Ra 0.2-0.8 μm on request |
| Alloys | 6061, 7075, 2024, ADC12 | Full list on request |
| Lot size | 1 to 10,000+ parts | No minimum order quantity |
| Inspection | 100% before shipment | Reports issued on request |
| DFM feedback | Within 12 hours | Free with every quote |
Since 2011 we have cut housings, covers and manifolds for automotive, medical and industrial customers. Cavity geometry is routine here, not a special request.
Three wholly-owned plants with 127 high-precision machines. Cavity parts do not wait in a queue behind unrelated work.
Enough 5-axis capacity to run prototypes and production lots at the same time without pulling a machine off one job.
Thin aluminum walls are held by controlling clamp pressure and roughing before finish, not by slowing the spindle down.
You get a price and a written DFM review within 12 hours of sending drawings. Production can start within 24 hours of approval.
ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. Your drawings stay confidential.
Cavities for boards and connectors, with flat mounting faces so gaskets seal.
Valve bodies and covers with internal passages that must not leak at test pressure.
Lightweight aluminum cavities that carry actuator loads without flexing.
Cavities with smooth internal radii that can be cleaned between uses.
Depth is limited by tool reach, not machine travel. As a working rule, pockets up to five times the cutter diameter are practical on our 5-axis centers because the tool can be tilted to stay short.
Beyond that ratio, we usually recommend a two-piece design or an EDM corner pass. We will tell you at DFM if your depth-to-width ratio is going to force a slower route.
Yes, on the features that matter, such as a bore or a sealing face. The overall wall thickness is normally held to ±0.03 mm because clamping and residual stress move thin aluminum more than the cutter does.
If your drawing calls ±0.005 mm on a 1.0 mm free-standing wall, that is a design problem, not a machining problem. We flag it before cutting.
6061-T6 covers most housings and covers. It machines well, anodizes evenly and is easy to source in plate and bar.
Choose 7075-T6 when the wall has to carry load or resist pressure. Choose 2024 for aerospace work that will get a protective finish. For machined die castings, ADC12 is the usual starting point.
Three things: shorten the tool, stiffen the setup, and clear the chips. We tilt the tool on a 5-axis machine to keep overhang low, use through-spindle coolant, and rough with a high-feed cutter that does not load the wall.
If a pocket still rings after that, we slow the finishing pass and take a lighter stepover rather than accepting a stepped floor.
Yes. ADC12 castings arrive with a skin and often with porosity near the surface. We take a cleanup pass of 0.4-0.8 mm before finishing, which keeps porous material out of sealing faces and threaded holes.
If porosity is severe, we will report it with photos instead of machining through it and shipping a leaking part.
Standard as-machined cavity walls and floors come out at Ra 1.6-3.2 μm. Our normal finishing target is Ra 0.8-1.6 μm, which is typical for gasket and O-ring seats.
Ra 0.2-0.8 μm is available where a drawing calls for it, usually on bores or sliding surfaces. We mask surfaces that must not be blasted or anodized.
We review the datum scheme before quoting. If the cavity and the bolt pattern share a datum, we cut them in one setup on a 5-axis machine so position does not depend on a second fixture.
Conflicting or missing datums get flagged in the 12-hour DFM note. Fixing a datum callout on paper is cheaper than scrapping a batch.
From one prototype to 10,000+ parts, with no minimum order quantity. Prototypes are machined from the same alloy as production so the fit check reflects the real part.
For larger runs we will suggest where a casting or a dedicated fixture lowers unit cost, but only when the volume justifies it.
Upload your STEP file and 2D drawing. We return a quotation and a written DFM analysis within 12 hours, and production can start within 24 hours of your approval.
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