Distributed control of hot bar thermode in fine pitch surface mount assembly

A hot bar thermode is viewed as a process with spatially distributed controlled variable (temperature) and disturbance (thermal load). A transfer matrix model, describing thermal inertia and heat propagation in the thermode, is defined and the model parameters are experimentally estimated. This model, implemented in software, is used to evaluate various control techniques: the existing single-input-single-output scheme, single-input-multi-output with weighted averaging of feedback signals, and adaptive single-input-multi-output scheme. A novel configuration of a hot bar thermode, suitable for multi-input-multi-output control is proposed. The efficiency of this technology is demonstrated by computer simulation.