Aluminium extrusion is a manufacturing process in which aluminium alloy is forced through a die with a specific cross-sectional profile. This versatile process allows manufacturers to create complex shapes with excellent surface finish and tight tolerances.
What is Aluminium Extrusion?
Aluminium extrusion works on a simple principle — a heated aluminium billet (cylindrical log) is pushed through a steel die using a hydraulic press. As the aluminium passes through the die opening, it takes on the exact shape of the die's cross-section. Think of it like squeezing toothpaste through a shaped nozzle.
The 6-Step Extrusion Process
Step 1: Die Preparation
The extrusion die is a thick, circular steel disc with an opening that matches the desired profile shape. Dies are precision-machined and preheated to 450-500°C to ensure even metal flow and maximize die life.
Step 2: Billet Heating
Aluminium billets (typically 6063 or 6061 alloy) are preheated in a gas or induction furnace to 400-500°C. At this temperature, the aluminium becomes soft enough to be pushed through the die but retains its solid form.
Step 3: Extrusion
The heated billet is loaded into the extrusion press container. A hydraulic ram then pushes the billet through the die at pressures ranging from 100 to 15,000 tonnes, depending on the profile complexity and alloy. The aluminium emerges from the die as a continuous profile at speeds of 5-50 meters per minute.
Step 4: Cooling & Stretching
As the profile exits the die, it passes through a cooling system (water quench or air cooling) to rapidly bring it to handling temperature. The profile is then stretched by 0.5-2% to straighten it and relieve internal stresses.
Step 5: Cutting
The continuous extrusion is cut to the required lengths — typically 3 meters or 6 meters for standard profiles. CNC saws ensure precise, clean cuts.
Step 6: Aging & Finishing
Profiles are artificially aged in a furnace at 175-200°C for 4-8 hours to achieve the specified temper (T5 or T6), which determines the final mechanical properties. After aging, profiles receive their specified surface treatment — anodizing, powder coating, or other finishes.
Why Choose Aluminium Extrusion?
- Complex shapes in a single piece (no welding or assembly required)
- Excellent strength-to-weight ratio
- Superior corrosion resistance
- 100% recyclable material
- Cost-effective for medium to high volume production
- Wide range of surface finish options
Applications
Aluminium extrusions are used everywhere — from window frames in your home to structural components in aircraft. The construction industry is the largest consumer, followed by transportation, electronics, and industrial sectors.
At Alument Industries, we operate PLC-controlled extrusion presses with 800 MT capacity, producing precision profiles for clients across India and international markets. Contact us for your aluminium extrusion needs.