Aluminium extrusion: precise temperature measurement for consistent profile quality

From billet heating to the press outlet, temperature measurement helps manufacturers balance extrusion speed, profile quality and die life. KELLER Pyrometer Systems provides non-contact measurement solutions tailored to the challenges of aluminium ex

Temperature is a critical process parameter in an aluminium extrusion press. Excessive temperatures can cause cracks, while insufficient billet temperatures increase resistance to deformation and accelerate die wear. During extrusion, friction generates additional heat, causing the temperature to rise along the profile. Reliable monitoring provides the information needed to adjust pressing speed and pressure.

Measuring aluminium presents particular challenges. The material emits little infrared radiation, and its emissivity—the ability to emit thermal radiation—varies with alloy composition, surface condition and measurement wavelength. Profile geometry also influences the measurement: a recess can produce a different reading from a flat surface at the same temperature.

KELLER addresses these requirements with application-specific pyrometers for the billet, die and extruded profile. High-sensitivity detectors and high-resolution optics enable non-contact measurement from a distance. Depending on the instrument, an integrated camera or pilot light assists alignment, while dedicated blocking filters suppress interference from daylight.

At the press outlet, the CellaTemp® PX 69 uses the EERC algorithm—Extended Emissivity Ratio Correction. This extends the two-colour measurement method to compensate for wavelength-dependent changes in aluminium’s emissivity ratio. The instrument processes the measurement signals in real time, enabling continuous monitoring of the moving profile without touching or marking its surface.

For production involving different profile geometries, EERC settings are established using reference temperature measurements. These settings can be stored in the plant control system and transferred to the pyrometer via IO-Link when the profile changes.

The practical advantages include:

- Continuous profile temperature monitoring at the press outlet.
- Non-contact measurement without probe-induced surface damage.
- Alignment options suited to industrial installation conditions.
- Temperature feedback to support extrusion speed and pressure control.
- Transfer of stored measurement settings during profile changes.

Discover KELLER’s temperature measurement solutions for aluminium extrusion presses.