Petter Hagqvist is doing research on a production method called additive manufacturing. This means that new components are produced by depositing melted metal wire layer upon layer. Temperature variations during the process are very important for the end result. A non-contact method for temperature measurement that works in this case has been missing. Petter Hagqvist and his colleagues tested whether it was possible to obtain information about the temperature by measuring ordinary visible light. For this they used a spectrometer.
“We made these measurements in parallel with other measurements, mostly because it was fun, and because we thought that there ought to be some information we could collect,” says Petter Hagqvist.
It was possible to obtain temperature information, but it was misleading, especially since the metal surface oxidizes during the process. Petter Hagqvist began making calculations to see if he could correct the measurement results. This eventually resulted in a totally new method; spectrometer measurements combined with data processing for correction of the results. The method has been tested experimentally and has proven reliable. Potentially it could be broadly used.
“Material properties are strongly influenced by temperature history. A rapid cooling often hardens a material, but there can also be cracks if it hardens too fast,” says Petter Hagqvist.
The new method can measure the temperature in situations where it was previously impossible. It could be used for monitoring and control of various types of welding processes. Other possible applications include monitoring combustion or steel processing. Further examples could be found in the electronics industry.
“It uses silicon wafers that are treated in various ways. One process involves heating the wafers under strictly controlled conditions,” says Petter Hagqvist.
University West is actively promoting the practical use in society of its researchers results. A patent of Petter Hagqvists method is submitted by a company established for this and similar purposes. The aim is to start cooperating with an enterprise that can make the method profitable.
