Curved aluminum composite panel construction is a powerful tool for improving the beauty of buildings, but the cold bending process, joint treatment, structural stability and other links are slightly difficult and prone to problems. The following are 8 typical problems and targeted solutions, with key parameters and process details:
1. Curved surface forming problems
1)Cold bending cracking/wrinkling
Phenomenon: The aluminum layer of the panel breaks or the core material wrinkles when bending
Cause:
Bending radius < minimum allowable value (3mm plate: R ≥ 60mm; 4mm plate: R ≥ 80mm)
Wrong bending direction (must be bent perpendicular to the core fiber direction)
Solution:
✅ Layered gradual bending method:
① Use a three-roll plate bending machine to apply pressure in 3 times (pressure 0.5MPa→0.8MPa→1.2MPa)
② Each bending angle is ≤15°, and the stress is released every 2 hours
✅ For sharp bends with small radius (R＜50mm), use 3mm thin plate + backing aluminum plate for reinforcement
2)Rebound deformation
Phenomenon: The arc surface rebounds and becomes straight after installation
Reason:
No bending compensation (rebound angle is about 3° 5°)
The curvature of the keel does not match the plate
Solution:
✅ Bending processing method:
Calculate the rebound amount, and bend 5% 8% more during processing (such as the design curvature is 30°, the actual bend is 31.5° 32.4°)
✅ Keel pre-adjustment:
Use a laser scanner to detect the curvature of the keel before installation, and readjust it when the error is > 2mm/m
2. Joint treatment problems
3) Bulging/cracking at the joints
Phenomenon: bulging at the arc joints or tearing of the glue seams
Cause:
Thermal expansion and contraction displacement is restricted (linear expansion coefficient of aluminum composite panels 2.3×10⁻⁵/℃)
Insufficient elasticity of the sealant (displacement capacity <25%)
Solution:
✅ Flexible joint system:
A[board seam width 8 12mm] > B[fill with closed-cell PE foam rod]
B > C[apply weather-resistant silicone glue (displacement capacity ≥50%)]
C > D[surface is concave arc]
✅ Staggered overlap: Hyperbolic panels use fish scale overlap (overlap ≥ 20mm) to avoid cross seams
4) Curved edge warping
Phenomenon: Edge aluminum composite panel separates from the edge strip
Cause: The edge strip is too rigid to deform with the curved surface
Solution:
✅ Customized flexible edge strip:
Use 1mm thick soft aluminum strip to replace traditional edge strip
Pre-bend into the designed arc and then glue and fix (structural glue + mechanical buckle)
3. Structural installation problems
5) The keel does not fit the curved surface
Phenomenon: There is a gap between the plate and the keel (>3mm)
Reason:
The cold bending accuracy of the keel is insufficient
The spacing between the hanging points is too large (>800mm)
Solution:
✅ Three-dimensional adjustable keel system:
| Components | Adjustment capability | Control accuracy |
| Main keel | Plane angle ±15° | 1° |
| Connecting claw | Radial displacement ±20mm | 0.5mm |
| Universal adapter | 360° rotation in space | 2° |
6) Surface flatness exceeds the standard
Phenomenon: 2m ruler checks the gap > 3mm
Reason:
Uneven thickness of the plate (tolerance > ±0.2mm)
Wrong installation sequence
Solution:
✅ Cross positioning method installation:
① First fix the center reference plate
② Expand the installation to both sides along the curvature ray direction
③ Use a laser surface meter to check every 3 plates installed
4. Special climate issues
7) Blistering due to high temperature exposure
Phenomenon: bulging of the board surface in summer
Reason:
PE core material expands at high temperature (volume increases by 1.5% at ＞70℃)
No exhaust channel on the back
Solution:
✅ Backing ventilation layer design:
The distance between the keel and the back of the board is ≥15mm
Reserve ventilation holes on the top/bottom (Φ10mm, spacing 1m)
✅ Choose high temperature resistant core material (such as rock wool core, resistant to 120℃)
8) Low-temperature glue joint failure
Phenomenon: Sealant becomes brittle and falls off below 10℃
Cause: Ordinary silicone glue becomes brittle at low temperature
Solution:
✅ Arctic Circle-grade sealant:
Select polyurethane MS glue (applicable to 40℃~100℃)
Glue injection temperature＞5℃, curing for 48 hours
Ultimate process guarantee measures
1. Digital preforming
Use 3D scanning to obtain the base point cloud → BIM modeling to optimize the board → CNC numerical control bending
2. Sample section test
Make a 3㎡ sample on site and withstand:
10 times 15℃~60℃ temperature cycle
8-level wind vibration test
2000lx ultraviolet irradiation for 168 hours
3. Special training for workers
Cold bending operators need to hold curved aluminum composite panel installation certification (pass rate <40%)
> Cost optimization tips: The hyperbolic surface can be disassembled into multiple single curved surfaces for splicing, and the processing fee is reduced by 60% (case: Guangzhou Baiyun Airport T2 Terminal Wave Ceiling)
Classic case problem review
Core formula for curved construction:
"One calculation (bending amount), two slowness (gradual pressurization), three ventilation (back cavity ventilation), four soft seams (wide seam elastic glue)"
Strictly following this can reduce the installation defect rate of curved aluminum composite panels from the industry average of 35% to less than 5%.
