Loading and unloading are mechanically different tasks. Loading a raw sheet is a lifting problem: the surface is continuous, the weight is distributed, and vacuum suction provides an efficient, non-marring grip. Unloading finished parts is a grappling problem: the surface is interrupted by cut profiles, the skeleton has no continuous area for suction, and the part geometry may be irregular.
Many automation systems solve this by using two separate manipulators—one vacuum head for loading, one gripper head for unloading—or by requiring the laser operator to intervene between cycles. Herochu’s composite truss manipulator for automated loading takes a different approach: a single end effector that switches between vacuum and gripper modes as the task demands.
The Composite Head Architecture
The Herochu composite truss manipulator combines a vacuum suction array and a mechanical gripper system in one unit. The vacuum array handles raw sheet pickup. The gripper system—forks, clamps, or a combination—handles finished part and skeleton removal.
The transition between modes is automatic. After the manipulator places a raw sheet on the cutting bed, it retracts. When the cutting cycle completes, the manipulator re-enters the bed area with the gripper system active. It lifts the cut part and skeleton, transfers them to a sorting station or finished-material cart, then rotates or reconfigures for the next vacuum load.
This single-head design eliminates the synchronization complexity of dual-manipulator systems. There is one gantry, one control loop, one set of positioning coordinates. The manipulator is always in the same spatial reference frame, whether it is loading or unloading.
Vacuum Subsystem Details
The vacuum array consists of independently controlled suction cups. Each cup has its own valve and pressure sensor. Through the PLC interface, the operator or control system can deactivate specific cups based on sheet geometry. For a full-size raw sheet, all cups engage. For a pre-cut sheet or a remnant, only the cups that will contact solid material are activated.
This selective activation is what makes the composite truss manipulator for automated loading viable for mixed-production environments. A fabricator running different part sizes and nesting layouts does not need to reconfigure the suction pattern manually. The control system stores suction configurations as recipes, retrieved automatically when the job changes.
Sheet separation is integrated into the vacuum sequence. The suction cups engage, then a controlled air blast or mechanical action breaks the adhesion between stacked sheets. Vacuum pressure monitoring confirms that only one sheet has been lifted. If pressure drops indicate a double-pick, the system alerts the operator and halts the load sequence.
Gripper Subsystem Details
The gripper mechanism is designed for the specific challenge of removing cut parts from a laser bed. After cutting, the sheet has been transformed: it contains drop-outs, narrow webs, and skeleton waste. The gripper must lift the entire assembly—parts plus skeleton—without dropping small pieces through gaps or crushing delicate cut edges.
Herochu uses a combination of fork tines and adjustable clamps. The forks slide under the cut sheet, providing support across its full width. Clamps secure the material to the fork structure during transfer. For small drop-out parts that cannot be supported by forks alone, the vacuum array can remain active in a supplemental mode, gripping individual pieces while the gripper handles the skeleton.
The gripper deposits material onto a double-layer finished-material cart or a sorting conveyor. The cart’s lower layer receives finished parts; skeleton waste goes to a scrap bin or separate collection point. The manipulator returns to the cutting bed empty, ready to receive the next raw sheet.
Control Integration
The composite truss manipulator for automated loading is governed by a PLC system with a touchscreen HMI. Recipe management allows operators to store and recall setup parameters for different jobs: suction cup patterns, gripper positions, traverse speed profiles, and deposit locations.
Communication with the laser cutter ensures that the manipulator and the cutting machine operate in sequence without conflicts. The manipulator does not enter the cutting bed until the laser signals cycle complete. The laser does not begin the next cut until the manipulator signals sheet loaded and positioned.
For multi-machine configurations, the control system can manage loading and unloading for two laser cutters from a single gantry. The PLC queues material demands from both machines, prioritizing based on cycle time and machine status.
Technical Specifications
| Parameter | Specification |
|---|---|
| Sheet Dimensions | 3015 / 4015 / 4020 / 4025 mm |
| Maximum Load | 100–500 kg |
| Skip Load | 3T |
| Air Consumption | 1.5 m³/min |
| Air Source | 0.6–0.7 MPa |
| Repeatability | ±2 mm |
| Traverse Speed | 10–30 m/min |
| Lifting Speed | 5–10 m/min |
Why a Composite Head
The alternative to a composite manipulator is a dual-manipulator configuration: one gantry with separate loading and unloading heads, or two entirely separate gantry systems. Dual-manipulator systems can achieve parallel loading and unloading—while one head unloads, the other loads—which reduces cycle time in theory.
In practice, the composite head offers advantages that dual systems struggle to match. The single head occupies less overhead space, which matters in facilities with limited vertical clearance. It requires only one set of rails and one drive system, reducing both capital cost and maintenance surface. And it eliminates the coordination complexity between two independent manipulators that must share the same storage access and cutting bed approach path.
For most sheet metal fabrication operations, the composite truss manipulator for automated loading delivers the required throughput without the added complexity of dual manipulators. The cycle time savings from parallel operation are real but modest, and they are often offset by the reliability gains and simpler maintenance of a single-head design.
The Practical Case
Herochu’s composite truss manipulator is engineered for fabricators who want automated loading and unloading without overcomplicating the production floor. One gantry. One manipulator head. One control system. The system handles raw sheets, finished parts, and skeleton waste in a continuous automated loop.
The composite head approach reflects a design philosophy: automation should reduce complexity, not add it. By integrating vacuum loading and gripper unloading into a single end effector, Herochu delivers the functional range of a dual-manipulator system with the mechanical simplicity that reliable 24/7 operation demands.
