What should be noted during the stretching process of aluminum profiles

1. Stretching must only be carried out on aluminum alloy profiles after they have cooled to below 50°C before being moved onto the stretching frame. If the temperature is too high during stretching, it can burn operators and damage the burrs. Moreover, it will not completely relieve the internal stress of the aluminum alloy profile, leading to warping, twisting, and functional defects before and after aging, rendering the product completely unusable.

2. The control of the stretching amount should be around 1%, and it is important to note that excessive stretching can result in size discrepancies at the head, middle, and tail, surface ripples (fish-scale patterns), low elongation, and increased hardness making the material brittle (low plasticity). Insufficient stretching will reduce the profile’s compressive strength and hardness, and even aging (quenching) will not improve hardness, making the profile prone to bending (commonly called a 'large knife bend').

3. To control the stretching deformation and properly manage the dimensional variation of the entire profile, appropriate specialized clamps and pads and suitable methods must be used. This is especially important for profiles with open sections, curved sections, cantilevered sections, and twisted shapes, where the proper and effective use of stretching clamps and pads must be ensured.

4. Pay attention to the stress conditions of areas such as small feet, thin teeth, long legs, curved surfaces, inclined surfaces, openings, and viewpoints on profiles with high width-to-thickness ratios, long cantilevers, large bends, uneven wall thickness, or unusual shapes, to avoid partial or point deformation, twisting, or spiraling defects.

5. Since burrs have a heat-retaining effect, aluminum profiles requiring a high-quality surface finish must be flipped multiple times in all directions to ensure uniform heat dissipation and reduce defects such as transverse bright spots caused by inconsistent crystallinity due to uneven cooling. This is particularly important for profiles with large wide surfaces or thicker walls.

6. During material handling, movement, and stretching, profiles must not collide, be pulled, stacked, congested, or entangled with each other. Adequate spacing between profiles must be maintained. Aluminum alloy profiles prone to bending or of varying lengths must be managed promptly, and protective measures between profiles should be implemented if necessary.