If there is enough space, using suspensions is the optimum solution for coupling the vacuum cups to the gripper. This is the best way of compensating for height differences on the surface to be gripped. Another advantage is that less precision is required in synchronizing
the robot’s extension motion with the machine’s ejection motion. This is usually one of the biggest problems when picking parts in injection molding machines. If the robot works faster than the tool’s ejection motion, it loses its vacuum and drops the part.
If the robot is operated too slowly, the tool’s ejection motion presses against the gripper and damages the vacuum cups and the robot’s linear bearings. It may seem more costly to fit each vacuum cup with a
strut, but in the long term this can lead to enormous savings by cutting maintenance costs and increasing the useful life of the gripper and robot. NB: Many types of strut for oval vacuum cups are available in a rotation-proof version to prevent rotation of the oval surface.