钣金制造文档

钣金设计完整参考——板材厚度表、折弯余量、K 因子、冲压和激光切割公差、材料选择指南以及详细设计规则。

1. 标准钣金厚度（板厚号）

钣金厚度通常用板厚号表示。使用以下图表将板厚号转换为材料的实际厚度。

板厚号	钢 (mm)	不锈钢 (mm)	铝 (mm)	铜 (mm)	典型用途
10	3.42	3.57	2.59	2.59	Heavy structural brackets, chassis
12	2.66	2.78	2.05	2.05	Automotive body panels, enclosures
14	1.90	1.98	1.63	1.63	General-purpose housings, panels
16	1.52	1.59	1.29	1.29	Electrical enclosures, covers
18	1.21	1.27	1.02	1.02	Consumer electronics chassis
20	0.91	0.95	0.81	0.81	Light-duty brackets, clips
22	0.76	0.79	0.64	0.64	Shielding, small brackets
24	0.61	0.64	0.51	0.51	Spring contacts, EMI shielding
26	0.45	0.48	0.40	0.40	Thin shims, washers, clips

2. 折弯余量与 K 因子

理解折弯余量对准确的平面展开至关重要。K 因子和折弯余量决定弯曲钣金零件的最终尺寸。

折弯余量公式

BA = (π/180) × A × (R + K × T)

A = Bend angle (degrees)
R = Inside bend radius (mm)
K = K-factor
T = Material thickness (mm)

标准 K 因子

R < TK = 0.25

R = T to 2TK = 0.33

R = 2T to 3TK = 0.40

R > 3TK = 0.45

最小折弯半径

Steel (CRS)0.5T – 1T

Stainless Steel0.75T – 1.5T

Aluminum 50521T – 2T

Aluminum 60611.5T – 3T (may crack at 1T)

Copper0.5T – 1T

Brass1T – 2T

最小法兰长度

For 90° bends≥ 4T + R

Single bend≥ 3 mm practical min

Multiple bends≥ 6 mm between bends

Near edges≥ 2.5T from hole edge

Near slots≥ 3T from slot end

Hole to bend≥ 2T + R

3. 冲压公差

Feature	Standard	Precision	Notes
Blanked edge profile	±0.1 mm	±0.05 mm	Sharp-edged tooling; better for thinner material
Pierced hole diameter	±0.05 mm	±0.02 mm	Punch-to-die clearance is critical
Hole-to-hole position	±0.1 mm	±0.05 mm	Progressive die: station-to-station accuracy
Hole-to-bend position	±0.15 mm	±0.1 mm	Affected by springback; bend before pierce
Bend angle	±1°	±0.5°	Overbend to compensate for springback
Formed feature depth	±0.2 mm	±0.1 mm	Coin or restrike for precision
Flatness	0.1 mm/100 mm	0.05 mm/100 mm	Leveling/stretcher after stamping
Burr height	≤ 0.1 mm	≤ 0.05 mm	Deburring available; specify on drawing

4. 激光切割规格

Material	Max Thickness	Min Kerf	Position Tol.	Quality
Carbon Steel	25 mm	0.15 mm	±0.1 mm	Clean edge; slight HAZ
Stainless Steel	20 mm	0.15 mm	±0.1 mm	Oxide edge — pickling available
Aluminum	12 mm	0.2 mm	±0.15 mm	Dross on thick sections
Copper	8 mm	0.2 mm	±0.15 mm	Reflective — fiber laser required
Brass	8 mm	0.2 mm	±0.15 mm	Zinc fumes — extraction needed
Titanium	6 mm	0.15 mm	±0.1 mm	Inert gas shield required

5. 钣金材料选择指南

Cold-Rolled Steel SPCC

最佳：General stamping, brackets, enclosures

避免：Outdoor use without coating

折弯：Excellent

Stainless Steel 304

最佳：Corrosion resistance, food-grade, medical

避免：Chloride/salt water (use 316)

折弯：Good

Stainless Steel 316

最佳：Marine, chemical, high-corrosion environments

避免：Cost-sensitive applications

折弯：Good

Aluminum 5052

最佳：Marine, chemical tanks, street signs

避免：High-strength structural parts

折弯：Excellent

Aluminum 6061

最佳：Structural, heat-treatable, aerospace

避免：Tight-radius bends (cracking risk)

折弯：Fair

Copper C110

最佳：Electrical bus bars, thermal, decorative

避免：High-strength mechanical loads

折弯：Excellent

Brass C260

最佳：Decorative hardware, electrical contacts

避免：Stress corrosion with ammonia

折弯：Excellent

Spring Steel 65Mn

最佳：Spring clips, retaining rings, washers

避免：Corrosive environments uncoated

折弯：Good

Zinc Sheet

最佳：Roofing, flashing, battery cases

避免：High-temperature applications

折弯：Good

Titanium Grade 2

最佳：Aerospace, medical, chemical processing

避免：Cost-sensitive; difficult to form

折弯：Fair

6. 钣金设计指南

Hole-to-Edge Distance

Minimum 2T from hole center to edge for punched holes. For laser-cut holes, 1T minimum. Insufficient edge distance causes bulging or tearing.

Hole Diameter vs. Thickness

Punched hole diameter must be ≥ material thickness (Ø ≥ T). Smaller holes require drilling or laser cutting. For holes < 1 mm, laser cutting is preferred.

Corner Radii on Blanks

External corners: minimum R = 0.5T. Internal corners: minimum R = 1T. Sharp corners create stress concentrations and accelerate tool wear.

Notch & Tab Width

Minimum notch/tab width = 1.5T. Width less than 1.5T risks tearing during stamping. For laser cutting, minimum slot width = material thickness.

Forming Height

Drawn/formed features: height ≤ 3× diameter for single-stage. Deeper draws require progressive stages and may need annealing between stages.

Grain Direction

Bend perpendicular to grain direction where possible. Bending parallel to grain increases cracking risk. Specify grain direction on drawings for critical parts.

Relief Cuts at Bends

Add relief notches at bend corners to prevent tearing. Relief width ≥ T, relief depth ≥ R + T. No relief = tearing at bend intersections.

Flat Pattern Design

Unfold your model to verify flat layout. Check for collisions. All bends must be linear — curved bends require special tooling and are cost-prohibitive.