Multi cavities die extrusion (Multi-strand Extrusion)

1. Characteristics of Multi-strand Extrusion

Multi-strand extrusion technology for aluminum and aluminum alloys involves employing effective process measures and optimizing various process parameters to simultaneously extrude multiple (n ≥ 2) identical or different aluminum alloy products through a single die, followed by subsequent processing to yield qualified products. Its main characteristics are:

(1) Effective process measures and optimized parameters: This includes the use of high-quality billet with uniform alloy composition, fine grain structure, purification and homogenization treatments; achieving isothermal extrusion conditions by optimizing temperature-speed specifications through measures such as billet gradient heating; and utilizing high-quality tooling featuring rational structural design, precision manufacturing, appropriate hardness, and superior surface quality and hardness.

(2) Multi-strand output (n ≥ 2): The number of strands depends on factors such as the extrusion press, container size, die dimensions, and product type. For example, a 12,500-ton press with a φ650 mm container and a φ1300 mm die can extrude over 50 small-diameter aluminum alloy rods in a single cycle. Similarly, a 2,500-ton press with a φ230 mm container and a φ425 mm die can simultaneously extrude four aluminum alloy (6063) hollow profiles or tubes for doors and windows.

(3) Synchronicity: Multiple product strands must flow out of the die holes simultaneously and at the same speed. The flow must be stable and orderly, smooth surface, straight shaped that facilitate subsequent processing.

(4) High-quality finished products: The extruded strands undergo necessary post-extrusion processes—such as dual-stage pulling, precision quenching (water, mist, air), sawing, stretching and straightening, and precision cutting—to yield high-quality final products.

2. Advantages of multi-hole extrusion technology

(1) Utilizing large extrusion presses, large extrusion containers, and large size billets to extrude multiple products in a single pass significantly boosts production scale and efficiency, reduces costs, and increases added value.

(2) Reducing the number of extrusion presses saves factory floor space and land, increases productivity per machine and per unit area, and lowers energy consumption, thereby greatly enhancing the economic and social benefits of the production line.

(3) Multi-hole extrusion significantly lowers the high extrusion ratios and forces required for single-strand extrusion, thereby reducing energy consumption per unit of product.

(4) Multi-hole extrusion reduces the total length of extrusion butt ends (scrap). Under isothermal extrusion conditions, metal flow is more uniform and exits the die holes synchronously, resulting in a smoother, flatter surface finish that facilitates downstream processing and automated continuous production; this ensures product quality, significantly increases the finished product yield, and substantially lowers costs.