Complete guide to bending aluminum sheet metal. Learn about alloy selection, temper effects, cracking prevention, and surface protection for aluminum parts.
Introduction
Aluminum bending presents unique challenges due to its low elastic modulus, soft surface, and varying properties by alloy. At Fulei Metal, we bend aluminum components for automotive, aerospace, and consumer goods clients.
Aluminum Bending Characteristics
Low elastic modulus (70 GPa) means more springback than steel despite lower yield strength. Soft surface is easily scratched. Different alloys and tempers bend very differently. Some alloys crack at tight radii.
Alloy and Temper Selection
Soft Alloys
5005-O: excellent bending, minimal springback. 3003-O: very soft, excellent bending. 5052-O: good bending, slightly stronger.
Medium Alloys
5052-H32: most common, good bending with moderate springback. 5005-H24: similar to 5052-H32.
Hard Alloys
6061-T6: challenging, prone to cracking, needs larger radii. 7075-T6: very difficult, rarely bent. 2024-T3: difficult, aerospace applications.
Minimum Bend Radii
Soft alloys: 0.5-1.0 times thickness. Medium alloys: 1.0-1.5 times. Hard alloys: 1.5-3.0 times. Always test new alloys.
Springback Compensation
Soft alloys: 1-2 degrees. Medium: 2-3 degrees. Hard: 3-5 degrees. Use real-time angle measurement. Update database with actual values.
Surface Protection
Apply protective film before bending. Use polished or chrome-plated tools. Use nylon inserts for critical parts. Handle with clean cotton gloves. Use interleaving paper between finished parts.
Cracking Prevention
Use larger bend radii for hard alloys. Bend across the grain. Use annealed material where possible. Deburr edges before bending. Test bend samples.
Tooling
Wider die openings reduce force and marking. Polished tools prevent scratching. Standard punches with appropriate nose radius work for most alloys.
Applications
At Fulei Metal, we produce aluminum bent parts for electronic enclosures, automotive brackets, heat sink components, lighting fixtures, and consumer electronics.
Conclusion
Aluminum bending requires understanding alloy-specific behavior. At Fulei Metal, our experience with all aluminum alloys ensures quality bent parts for international clients.
Alloy and Temper: Where the Cracking Risk Sits
Aluminium problems almost never come from aluminium as a material — they come from choosing a temper that was never intended to be formed. The difference between two common alloys is large enough that the same flange will pass in one and crack in the other.
| Alloy / temper | Typical minimum radius | Notes for the designer |
|---|---|---|
| 1100-O | 0 to 0.5 × t | excellent formability, can often be folded flat |
| 3003-H14 | 0.5 to 1 × t | good general purpose choice |
| 5052-H32 | 1 × t | the usual pick for marine and outdoor parts |
| 6063-T5 | 1 to 1.5 × t | bends better than 6061 for the same family |
| 6061-T6 | 2 to 3 × t | poor bendability; if a drawing shows 1 × t, question it before quoting |
Two aluminium-specific behaviours catch people out. First, springback is high and varies with temper far more than steel does, so a program validated on one batch should be re-verified on the next. Second, alloys chosen for machinability — 6061 is the classic case — are usually poor choices for forming. Where both matter, forming in a softer temper then heat treating is often the honest answer, though it adds a process step.
Storage and handling deserve a note as well. Aluminium marks easily and those marks survive almost every finishing route, so racked storage and clean gloves are process requirements for cosmetic aluminium rather than niceties. If the part will be anodized, say so at quoting — anodizing makes any forming mark more visible, not less.
Frequently Asked Questions
Can you match an existing part made from 6061 without cracks?
If the drawing calls for a radius of at least 2 × t, usually yes. Below that, we form sample coupons from the actual batch before quoting rather than promising a result the material will not support.
Does anodizing affect bending?
Not bending itself, since anodizing follows forming. But it does make any forming mark more visible, so surfaces destined for anodizing need the same care in bending as polished stainless.
Why is aluminium harder to hold to angle than steel?
Because it has a lower elastic modulus, so more of the deformation returns after the load is removed. Combined with temper-to-temper variation that makes springback harder to predict from a table.
Questions about a specific part are usually faster to answer against the drawing — send it through the review route below.
Next step. Send the drawing for a aluminium forming capability. We confirm the die set and the achievable radius before quoting, so the numbers you receive describe this part rather than an average. Useful background: forming another high-springback material, why aluminium behaves differently and alloy and temper review.