Application experience of a robotic cell for automated adhesive dispensing

The need to have high integrity, structurally bonded adhesive and sealant joints throughout many industries, such as the automotive and aerospace industries, is increasing. To ensure process integrity, strict process control of the automated dispensing cell is essential. Many industries require the use of continuous beads of adhesive or sealant in applications where the integrity of the joint is critical, e.g., structural bonding or gasket sealing. A continuous and uniform bead gives required strength for good performance of the joints. For these reasons, the dispensed adhesive needs to be consistent. The consistency is a function of the amount of dispensed material and its displacement. The dispensed material is controlled through a closed-loop system which is built around a six-axis robot carrying a digitally controlled dispensing gun, a single-axis linear table carrying the workpiece, and a vision system for on-line inspection and image processing. The bead parameters obtained by image processing are used by the controller to ensure that the bead stays in the desired bandwidth, whilst it is being laid down.