Software for real time temperature control

The control of temperature during laser materials processing is of primary concern. The temperature achieved is the main experimental condition for all laser processing. A temperature control system has been developed which uses direct digital PID control. This controls the temperature at the workpiece using a dual wavelength pyrometer. The benefits of such a system are that the effect of the variation of emissivity with temperature is removed, providing more accurate temperature measurement. The performance of the system has been evaluated by considering the stability and response time of the controller. The temperatures measured have been confirmed experimentally by thermocouple measurements and transformation hardening of mild steel