Five Key‑Selection Parameters for 3‑Axis Manipulators Interpretation of Critical Indicators

The 3‑axis manipulator serves as core handling equipment for single‑press multi‑station stamping lines. Five critical parameters should be considered for equipment selection: payload, stroke, speed, accuracy and mounting method.

Payload Capacity Payload refers to the maximum weight the manipulator can grip. Instead of merely checking the static weight of workpieces, dynamic inertial force generated during high‑speed traversing, lifting, start‑up and stop shall be taken into account, as such force superimposes on static weight. It is recommended to reserve a 30%‑50% payload margin to avoid overload‑induced vibration and positioning deviation under high‑speed operation. For instance, if the total weight of workpiece plus gripper is 20 kg, select a model with rated payload above 30 kg.

Stroke A 3‑axis manipulator has strokes in three directions: X‑axis traverse stroke, Y‑axis lifting stroke and Z‑axis advance‑retreat stroke. The X‑axis stroke must cover the distance from the first station to the last station according to station quantity and station pitch. The Y‑axis stroke is determined by die height and workpiece pick‑and‑place height, enabling grippers to reach the bottom of die cavities for part picking and rise above the safe height before traversing. The Z‑axis stroke depends on die opening depth and manipulator installation position, ensuring grippers can reach the deepest die position for picking and fully retract without interfering with press operation.

Speed Manipulator speed shall match press takt time. The manipulator’s cycle time for material pick‑and‑place must be shorter than the press slide motion cycle; otherwise it cannot retract before die closing. During selection, calculate the minimum cycle time under three‑axis simultaneous motion plus gripper opening‑closing time to verify whether the total cycle can satisfy the maximum takt requirement of the press. Insufficient manipulator speed will bottleneck the whole production line.

Accuracy Repeat positioning accuracy determines the placement consistency of workpieces inside dies. High repeat positioning accuracy delivers stable dimensional performance of stamped products. For products with strict consistency requirements such as automotive outer panels, repeat positioning accuracy of manipulators is generally required within ±0.1 mm. Reliable accuracy relies on high‑rigidity mechanical structures, precision linear guideways and high‑resolution servo encoders. Structural rigidity and guideway accuracy grade should be evaluated rather than only referring to nominal accuracy values.

Mounting Method Two mounting types are available: gantry‑type and floor‑standing type. The gantry type is installed above the press and fits large‑size presses and heavy workpieces; it saves floor space yet requires sufficient workshop ceiling height and beam load‑bearing capacity. The floor‑standing type stands beside the press, suitable for medium‑and‑small‑size presses with easier installation and maintenance but occupying floor area. Selection shall take workshop ceiling height, press layout and maintenance access into consideration.

Replacing manual handling between multi‑station dies, 3‑axis manipulators realize three‑axis coordinated motion featuring high speed and consistent positioning, guaranteeing product quality. Operators only perform patrol inspection outside the hazardous stamping zone and are kept away from potential safety risks.

Guangdong Ruihui Intelligent Technology Co., Ltd. has over 20‑year experience in stamping automation and is a national Specialized, Refined, Differentiated and Innovative “Little Giant” enterprise. Headquartered in Dongguan, it has more than 400 employees including over 80 R&D engineers. Ruihui possesses rich practical experience in 3‑axis manipulator selection. It conducts matching calculation for payload, stroke, speed and accuracy based on customers’ workpiece weight, station quantity, die layout and press takt to ensure stable and high‑speed manipulator operation. Nearly 5,000 sets of Ruihui‑manufactured equipment are running at domestic and overseas customer sites, serving well‑known OEMs and Tier‑one suppliers such as BYD, Geely, Volkswagen, Tesla, BMW, Mercedes‑Benz, Honda and Jaguar Land Rover.