AMETEK Land - Light Metal Age - Non-Contact Temperature Measurement for Wrought Aluminium
Accurate temperature measurement is critical in aluminum rolling and extrusion processing. This article will address the importance of accurately measuring the temperature at various stages in the manufacturing of these wrought aluminum products, particularly rolled aluminum, presenting both challenges and solutions.
There are two main sensor types: contact temperature measurement sensors and non-contact pyrometers. Contact temperature measurement sensors, such as thermocouples, work in direct contact with the material being measured. They are not suitable for continuous temperature measurement in manufacturing methods with moving products, such as rolling or extrusion. Since the temperature reading can van' depending on the amount of pressure applied, the probe must also be in contact for a few seconds in order to stabilize the product's temperature. Furthermore, contact probes can mar die surface finish of the final product.
Non-contact pyrometers—either radiation thermometers or process thermal imagers—have none of the surface contamination issues associated with contact probes and are ideally suited for moving products. Pyrometers can respond rapidly, usually in less than 20 ms. Their non-contact operation means that they can operate for many years with little or no maintenance, since they simply view the radiation that is emitted from the material surface. Non-contact process thermal imagers, which are able to provide a wider temperature scan of the material, are especially suitable for flat strips and slabs, where measurement of overall temperature uniformity is important.