Hemming in automotive manufacturing is a cold process of joining an inner and outer panel by folding the flanges of the outer panel onto the inner panel, permanently clamping the inner panel in place. This process is used in the manufacture of doors, hoods, and decklids and can be accomplished using a traditional press or with a robotically controlled roller.
In a robotic roll hem operation, the outer panel is placed with its exterior surface down on an anvil. The inner panel is then located and held in place while a robotically held roller hems the two panels together. Because the anvil is holding an exterior, class ‘A’ surface, it must be precision machined to avoid marring or deforming the part. A single hemming cell may require multiple anvils to accommodate various models.
Comau has introduced a new “Smart Hemmer” intended for use on electric, hybrid and lightweight vehicles which reduces cost by eliminating the need for expensive anvils. The unique design features two rollers engaging the part. The inner roller can automatically retract to maneuver around obstacles or adapt to a curved path.
This feature reduces the need for the frequent reposition moves required by traditional hemming robots to adjust to complex angles. The result is a fast, efficient, continuous process which can maintain a uniform hem even with multiple layers of dissimilar materials. The “Smart Hemmer” has been field tested by major European automakers. It is Industry 4.0 compliant and offers full in-process monitoring of each hem.