Robot Loading and Unloading for Multiple Presses in Tandem Stamping Automation Solution for Large Sheet Metal Parts

The stamping production of large sheet metal parts is different from that of small and medium-sized parts. The workpieces are large in size and require many operations. A single press has a limited bed area and cannot accommodate so many die sets, so the operations must be split and performed on multiple presses. Multiple presses are arranged in a line according to the process sequence, and workpieces are transferred between them. This transfer step used to rely on manual labor—large and heavy sheet metal parts were difficult to carry and prone to bumps and collisions. Today, using robots for loading and unloading across multiple presses in tandem has become the mainstream solution for stamping automation of large sheet metal parts.

The basic composition of this solution is as follows: multiple presses are arranged in a row according to the process sequence, with each press handling one operation. Between every two presses, a six-axis industrial robot handles loading and unloading transfer. At the front end, destacking and feeding equipment delivers blanks to the first press; at the back end, part collection and stacking equipment automatically gathers finished parts from the final operation. The entire line, from blank loading to finished part collection, runs fully automatically, with no manual handling of material between presses.

The robot's working logic in this solution is as follows: after the previous press completes its stroke and the slide rises to the top position, the robot removes the workpiece from the die. The robot carries the workpiece to the next press, positions it above the die, places it in position, and exits the die area. The next press confirms that the robot has retreated to a safe position before beginning its stroke. The robot's pick, transfer, and place actions are strictly coordinated with each press's cycle. Cycle after cycle, the entire line runs continuously.

Why are robots suitable for loading and unloading large sheet metal parts? First, because the workpieces are large. Large sheet metal parts are big and heavy, difficult for workers to carry, and very prone to surface damage during handling. Outer panels have high surface quality requirements—any bump or scratch means scrap. Robots use multi-point vacuum suction cups to pick up parts, distributing force evenly without causing local deformation or surface scratches like manual gripping. Their protection of surface quality is far superior.

Second, flexibility. A six-axis industrial robot has six joints, making its motion extremely flexible. Large sheet metal parts sometimes need to be flipped or angle-adjusted between operations. The robot can perform these tasks, rotating the workpiece into the required orientation for the next operation before placing it. This flexible posture adjustment capability is key to handling large parts.

Third, efficiency and consistency. The robot places parts with precise repeatability—every pick and place is consistent—ensuring product dimensional consistency. Robots do not tire and maintain a stable cycle time during continuous operation. Overall line efficiency is much higher than with manual loading and unloading, boosting capacity while reducing workers' physical strain.

Safety is beyond comparison. The most dangerous aspect of a stamping shop is manual loading and unloading—especially on large presses with massive dies and high tonnage. Workers reaching into the die area risk severe injury if they make a mistake. The robot tandem line completely replaces human operators in hazardous areas; workers only need to monitor equipment from safe zones. There are comprehensive safety interlocks between the robots and presses, along with safety fences and light curtains, greatly reducing the risk of workplace injuries.

When planning this solution, several aspects must be carefully considered. First, the robot's payload and reach must match the part size and weight—large parts are big and heavy, and insufficient payload means they cannot be moved. Second, the number of robots: one between every two presses, configured according to the number of operations. Third, timing coordination between robots and presses: signal interactions for picking, placing, and stamping must be precise and reliable. Fourth, front-end and back-end equipment integration: destacking, feeding, collection, and stacking must coordinate smoothly with the middle stamping line. Robot loading and unloading for multiple presses in tandem transforms the stamping of large sheet metal parts from a labor-dependent process into an automated flow, raising efficiency, quality, and safety to a new level.

Guangdong RuiHui Intelligent Technology Co., Ltd. has been deeply engaged in the field of stamping automation for over twenty years. It is a national "Specialized and Sophisticated" "Little Giant" enterprise, headquartered in Dongguan, with more than 400 employees and over 80 R&D personnel. RuiHui's multi-press tandem robot stamping lines are widely used in the production of large sheet metal parts. They can be configured with six-axis industrial robots based on product characteristics and cycle time requirements, with payload and reach customized to workpiece dimensions. They provide complete line integration from front-end destacking and feeding to back-end collection and stacking, with comprehensive safety interlocks and timing coordination between robots and presses. RuiHui has supplied multi-press tandem stamping automation lines to numerous automotive OEMs and first-tier suppliers. With nearly 5,000 sets of equipment operating at customer sites both domestically and internationally, serving well-known companies such as BYD, Geely, Volkswagen, Tesla, BMW, Mercedes-Benz, Honda, and Land Rover Jaguar, RuiHui has rich practical experience.