Thin walls save weight and material cost but create manufacturing problems: warping during machining, incomplete fill in molding, cracking during heat treatment, failing in service. This reference table shows minimum reliable wall thickness by process and material — with data from production runs, not theoretical limits.
| Material | Min wall (production) | Min wall (prototype, care) | Notes |
|---|---|---|---|
| Aluminum 6061 | 1.0 mm | 0.5 mm | Below 1mm, wall bows during machining |
| Aluminum 7075 | 1.2 mm | 0.6 mm | Slightly more brittle than 6061 at thin sections |
| Stainless 304/316 | 1.5 mm | 0.8 mm | Work-hardens; prone to chatter on thin walls |
| Steel 1018/4140 | 1.5 mm | 0.8 mm | Check for heat-treat warp on <2 mm walls |
| Titanium Ti64 | 2.0 mm | 1.0 mm | Springback & deflection — wall flexes during cut |
| Delrin / POM | 1.2 mm | 0.6 mm | Low stiffness means chatter below 1 mm |
| PEEK | 1.5 mm | 0.8 mm | Thermal expansion causes warp on thin sections |
| UHMW | 2.5 mm | 1.5 mm | Rubbery — thin walls flop during machining |
Injection molding has different constraints: material must flow into the cavity and fill completely before cooling.
| Resin | Min wall | Max wall (before sink) | Flow length (typical) |
|---|---|---|---|
| ABS | 0.8 mm | 3.5 mm | 150-200 mm |
| PP | 0.6 mm | 4.0 mm | 150-250 mm |
| PC (polycarbonate) | 1.0 mm | 3.5 mm | 120-180 mm |
| Nylon (PA6, PA66) | 0.8 mm | 3.5 mm | 80-150 mm |
| TPE | 1.0 mm | 5.0 mm | 60-100 mm |
| PEEK | 1.2 mm | 3.0 mm | 40-80 mm |
Wall-thickness uniformity matters as much as absolute thickness. Ideally keep all walls within ±25% of nominal. A 2mm wall next to a 5mm wall will cool at different rates, causing sink marks, warpage, and residual stress.
| Technology | Min wall | Notes |
|---|---|---|
| FDM / FFF | 1.2 mm (3 perimeters × 0.4mm nozzle) | Below 1.2mm walls are gappy |
| SLA / DLP | 0.6 mm | Below 0.6mm, walls flex during resin wash |
| SLS (nylon powder) | 0.8 mm | Below 0.8mm, walls crack during powder extraction |
| MJF | 0.8 mm | Same as SLS — powder extraction risk |
| DMLS (metal) | 0.5 mm | Below 0.5mm, incomplete fusion is likely |
Sheet metal isn't about wall thickness, but sheet gauge. Common sizes stocked:
Specifying odd sizes (like 1.3 mm aluminum) triggers material sourcing delays and premium pricing. Stick with stocked sizes unless there's a specific reason.
Email [email protected]. If your design has walls at our practical minimum, we'll confirm it's producible — or suggest a small thickness bump that eliminates manufacturing risk.
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