Case: robot cell

The trays arrive one by one to the robot cell on a conveyor from a thermoforming machine and are fed to the stacking tower so that they can be stacked in heights of 600 mm, 800 mm or 1000 mm.

The stacking tower stacks the trays traditionally. When a stack is completed it is raised and a slide is moved in under the stack. The stack is placed on the slide and the slide is then moved to a position from where the robot can pick up the stacks.

The robot picks up the stacks from the stacking tower using the tray gripper, which by means of two jaws grips the tray and presses them to a defined height being measured by means of a laser distance meter. When the correct distance has been reached, the pressure in the cylinder is reduced to a holding pressure and the stack is moved to the foil welder by the robot.

The foil opener opens the foil, which is a double foil, bent around at the bottom and with a welding on one side. The tray gripper with the trays is moved into the foil opening and the foil opener returns. The trays are then moved to a lifting shelf.

The tray gripper is pulled out. Now the lifting shelf is lowered so that the welding is positioned at the middle of the tray ensuring that the bag is welded correctly. When the welding is finished the welding boom is raised 25 mm and the lifting shelf lifts the bag with the trays so that they are ready to be picked by the robot.

The robot exchanges the tray gripper for a vacuum gripper. The vacuum gripper lifts the bag with the trays and places it in the required pattern on the pallet. When the bag has been placed the vacuum gripper is exchanged for the tray gripper and the robot returns to the starting point.

When the pallet is full the tray gripper is used for lifting a shielding at the stacking tower so that this can go on running while the pallet is changed. When the robot is in a position next to the shielding the pallet is ready to be changed and the sliding door is unlocked. When the pallet has been changed, a push button is pressed. Now the sliding door can be locked and the robot cell continues its operation.

This procedure is also used for change of foil. The foil spool is changed and the foil is threaded through the guides. The foil is welded in order to close one side of the bag. Now the foil welder is again ready for production.

The robot cell is constructed in such a way that unnecessary stops are avoided.