For optimal extrusion results, billets must be preheated to ensure that the extrusion exit temperature remains within the alloy’s solution heat treatment range (e.g., 515–535℃ for alloy 6063). Proper control of preheating temperatures according to alloy type and product geometry ensures excellent surface finish, consistent mechanical strength, and uniform anodized color.

To ensure stable extrusion, dies are preheated to maintain the proper bearing section temperature as the billet passes through. Preheating conditions vary depending on alloy type, product geometry, and die size.

In the extrusion process, billet length and processing parameters are carefully optimized by considering profile characteristics, extrusion ratio, run-out table length, and press capacity. This ensures stable production and consistent quality.

Proper cooling is critical to maintaining the quality of extruded products. If cooling is insufficient, it can lead to reduced tensile strength and elongation after heat treatment, as well as surface defects such as inconsistent anodizing or coloring.

To enhance mechanical strength and maintain dimensional straightness, extruded profiles undergo a straightening process. Typically, profiles are stretched by about 0.5% of their length. Stretching beyond 2% may result in defects such as orange peel and dimensional inconsistencies.

Extruded profiles are cut to the required product length. Clamp marks from the stretcher and joint overlaps at both ends are removed as scrap to ensure product quality.

To ensure the required mechanical properties, extruded profiles undergo an aging process. This involves controlled heating cycles defined by ramp-up time, ramp-up temperature, holding time, and holding temperature. Specific aging conditions vary according to the profile type and application.

For extruded profiles requiring corrections that cannot be fully achieved by die design, rolling is applied either before or after heat treatment. This finishing process is primarily used on products over 250 mm in width to ensure proper squareness and flatness.