Indirect Extrusion Presses

In a typical indirect extrusion process, the die is mounted on a hollow stem or corresponding actuating structure and moves toward the billet. Metal passes through the die and exits in the direction opposite to the die motion. Because the billet remains essentially stationary relative to the container, sliding friction between the billet and the container wall is significantly reduced.

1. Billet is loaded into the container and process preparation is completed.
2. The die and its support structure move toward the billet.
3. Metal passes through the die orifice and exits along the internal channel of the hollow stem or extrusion ram.
4. There is essentially no relative sliding between the billet and the container.
5. Forming stability is maintained through equipment, die and process control.

• Profiles requiring higher dimensional stability along the extrusion length
• Products sensitive to temperature and load variation during extrusion
• Products suitable for indirect extrusion after section, material, die and equipment structure evaluation

The actual degree of improvement in indirect extrusion depends on material, billet surface, temperature, extrusion ratio, die, speed and equipment control, and must be evaluated against the specific product conditions.

• Reduces sliding friction between billet and container wall
• Extrusion force and temperature rise typically vary more smoothly during the process
• Helps improve dimensional, structural and property consistency along the extrusion length
• Die, hollow stem or extrusion stem structure affects the boundary of producible sections
• Requires corresponding attention to equipment alignment, die support and billet surface condition