A Software System to Accurately Calculate Parts Temperature for Hot Stamping

Abstract

Infrared thermal imaging system is a key component in hot stamping and is commonly used to collect parts temperature during the part production process. However, due to the inappropriate setting of the emissivity, the output produced via such system usually lack accuracy and consistency. A ± 150 °C temperature measurement error was observed at several hot-stamping lines. In this paper, a new infrared software system is proposed to calculate parts temperature by utilizing a mathematical model behind the scenes. The system factorizes 3D model of the part, position of the thermal camera and parameters of the environment to calculating the directional emissivity, which is further used to compensate the output obtained from the thermal camera. Compared to traditional thermal systems, the proposed software system achieved 83% increase in accuracy (±25 °C vs ±150 °C in measurement error). Nonetheless, usage of such software system will be discussed. For example, double sheet detection for hot stamping line have been implemented by setting the threshold of part temperature and dispatch warnings to PLCs via ProfiNet or Ethercat protocol. In combined with IIot and machine learning techniques, quality prediction system for hot stamping have also been built.