Safeguarding a Single-Station Robot Weld Cell
The challenge in a single-station robot weld cell safeguarding application is to increase operator access to the weld station while effectively safeguarding the operator from the hazard. In this application, the operator places the part in the tooling station, leaves the open hazardous area, and then cycles the robot to begin work. When the robot completes the weld and moves to a safe state, the operator re-enters the area, removes the finished part, and begins a new cycle by placing a new part in the station. Using a safety scanner to safeguard the operator allows optimal access to the area, and can also increase productivity.
Banner Engineering's AG4 Safety Laser Scanner is placed at the base of the hazardous area and “looks out” at the open area. It is programmed via a PC with interface software to guard the area between the physical barriers (the protective zone) and outside the barriers (the warning zone). If the operator or other personnel approach the hazardous area during robot operation, a signal is sent to alert the person that the warning zone has been entered; the robot continues operation during this time. If the protective zone is entered, the robot and other hazardous machinery are stopped. This configuration reduces the number of nuisance trips and unnecessary down-time by warning personnel to stay out of the protective zone, and allowing the robot to continue its work cycle.
A safety laser scanner is a cost-effective safeguarding and productivity-enhancing solution to other safeguarding devices in this application. Safety mats are costly and deteriorate rapidly in high-traffic areas. Safety light curtains can be positioned to safeguard access to a hazard, but have no means of warning personnel that they are approaching the hazardous area, which can result in nuisance trips. Protective barriers using gates with safety interlocks effectively guard the area, but limit access for the operator and increase the amount of time between cycles. If the work station is reconfigured, the scanner can be re-programmed to adjust to the new work cell dimensions and parameters.