Bent & welded. Or machined from solid. Very different results.

For small enclosure (100 × 100 × 50 mm): sheet metal $25–50 per unit vs CNC unibody $150–400. Sheet metal is 3–6× cheaper due to: starting from flat sheet (cheaper raw material), less machining time (mostly laser cutting + bending vs extensive milling), better material utilization. CNC unibody starts from solid billet — 70–90% of material becomes chips. For high-volume, this cost gap widens.

When brand positioning demands premium appearance (Apple, high-end audio, luxury wearables). When perfect EMI integrity matters (sensitive RF equipment). When thermal management is critical and heat sink integration makes sense. When weight matters and hollow geometry enables weight savings despite solid starting block. For most industrial and mid-market applications, sheet metal is the right choice.

Common. Example: CNC-machined front panel with precision cutouts for displays and controls, sheet metal body with PEM hardware, overall assembly with fasteners. This gives premium appearance on visible surfaces with cost-effective construction on back. Another approach: CNC unibody top shell + sheet metal bottom pan. Balances premium look with cost.

Sheet metal: IP66 achievable with proper gasketing. Compression gaskets between panels, sealed cable glands, edge-sealed fasteners. IP68 (continuous immersion) possible but requires careful design. CNC unibody: IP68 easier because fewer sealing joints. Single gasket between body and lid. For submersible products, unibody has inherent advantages in sealing integrity.

Sheet metal: easy to modify cutout patterns, add/remove PEM holes, change bend locations. Design changes accept same laser program + adjusted bend setup. Fast iteration between versions. CNC unibody: requires CAM reprogramming for design changes. More expensive to iterate. For products expected to change frequently, sheet metal wins on development cost.

Sheet metal: linear scaling — 1000 enclosures is 10× the cost of 100, minus modest learning curve. CNC unibody: similar linear scaling since no tooling. For very high volumes (10,000+), both processes remain viable. Sheet metal at extreme volume may transition to progressive die stamping for cost reduction. CNC unibody at extreme volume typically stays CNC or transitions to die casting (aluminum cast with machined features).