Shenzhen Alu Rapid Prototype Precision Co., Ltd.
Industry News
Short answer: Sheet metal fabrication is usually the cheapest way to make functional enclosures, brackets, and chassis from 1 to 1,000+ parts. Typical tolerances are ±0.1–0.2 mm, and the main cost drivers are material, laser/plasma cutting time, bend count, and finishing.
This guide covers the processes, the materials, what tolerance to expect, and where the money actually goes.
The Core Processes
| Process | What it does | Typical use |
|---|---|---|
| Laser cutting | Cuts flat profiles with high accuracy | Complex outlines, holes, thin sheet |
| Plasma cutting | Cuts thicker plate | Heavy-gauge brackets, frames |
| CNC punching | Punches standard shapes rapidly | High-volume perforated parts |
| Press braking | Forms bends | Enclosures, brackets, chassis |
| Welding | Joins formed parts | Assemblies, frames, tanks |
| Insertion | Adds rivet nuts, standoffs | Threaded attachment points |
Materials
| Material | Relative cost | Characteristics | Typical use |
|---|---|---|---|
| Mild steel (SPCC, CRS) | $ | Strong, cheap, needs coating | Chassis, brackets, frames |
| Galvanized steel (SGCC) | $ | Corrosion resistant without coating | Electrical enclosures |
| Stainless 304 | $$ | Corrosion resistant, harder to form | Food, medical, outdoor |
| Aluminum 5052 | $$ | Best forming aluminum, corrosion resistant | Enclosures, panels, covers |
| Aluminum 6061 | $$ | Stronger, but cracks on tight bends | Brackets, machined-flat parts |
| Copper / brass | $$$ | Conductive, decorative | Busbars, EMI shielding |
Important: for parts that must be bent, choose 5052 aluminum, not 6061-T6. The T6 temper makes 6061 brittle and it will crack under aggressive forming.
Tolerances You Can Expect
| Feature | Typical tolerance |
|---|---|
| Cut profile dimensions | ±0.1–0.2 mm |
| Hole position | ±0.1 mm |
| Bend angle | ±0.5° – ±1° |
| Bend position | ±0.1–0.3 mm (depends on material and bend length) |
| Overall assembly | ±0.3–0.5 mm |
Bending is where accuracy is hardest to guarantee, because material spring-back varies. Longer bends and thicker sheet magnify the error. Where a tight dimension matters, ask for it to be measured across a cut feature rather than across a bend.
Design Rules That Reduce Cost
Keep bend radii consistent — one tool set-up instead of several
Respect minimum bend radius — roughly 1× material thickness for aluminum, 0.5–1× for steel
Leave room at the bend — holes and slots too close to a bend will distort
Design for the standard sheet size — nesting efficiency directly affects material cost
Minimize the number of bends — each one adds handling, tooling, and error
Use standard hardware — common rivet nuts and standoffs are far cheaper than custom inserts
Where the Cost Actually Goes
Material — driven by sheet area, thickness, and nesting efficiency
Cutting time — laser speed depends heavily on thickness and material
Bending — cost per bend, plus set-up time
Welding and assembly — usually the largest labor item on complex enclosures
Finishing — powder coating, anodizing, plating, or painting
For simple flat parts, finishing often costs more than the fabrication. See our sheet metal fabrication capabilities and surface finishing capabilities.
FAQ
What is the cheapest sheet metal material?
Mild steel and galvanized steel. Aluminum 5052 costs more but resists corrosion without coating.
Can you bend 6061 aluminum?
Only with generous radii and usually in the annealed temper. For tight bends, use 5052 instead.
What tolerance can sheet metal hold?
About ±0.1–0.2 mm on cut features, but ±0.5 mm or worse across bends and assemblies.
Is sheet metal cheaper than CNC machining?
Usually yes for enclosures and brackets, especially at higher volumes. For complex 3D geometry, CNC is the right process.
How do I get a flat pattern?
Provide a 3D model with sheet thickness and we will generate the flat pattern, K-factor, and bend deductions for you.
Get a Quote
Send your 3D model or drawing with material and finish noted, and we will quote cutting, forming, welding, and finishing together.