Sheet metal storage in most fabrication shops follows a simple model: pallets stacked on the floor, organized by material grade and thickness, retrieved by forklift when needed. This approach consumes floor space, creates safety hazards, and adds time to every job changeover. Herochu’s laser automation loading unloading system replaces this model with vertical storage towers that integrate directly with gantry loading robotics, converting static material inventory into an active, automated supply chain for laser cutting operations.
Vertical Storage Tower Design
The Herochu storage tower stacks sheet metal horizontally in multi-tier racks, with each layer functioning as an independent storage position. The HC-A series supports 8 to 10 layers depending on model configuration, with 350 mm clear space between tiers to accommodate various plate thicknesses and surface treatments.
Each tier carries up to 5000 kg of material (3000 kg on the HC-A3015-83 model), allowing the tower to hold substantial raw material inventory in a compact footprint. By stacking vertically rather than spreading pallets across the shop floor, the system reclaims up to 70 percent of the floor space previously dedicated to material storage.
The tower’s internal mechanism retrieves sheets from any tier on demand. When the laser cutting machine signals for material, the tower selects the correct tier based on the job schedule, extracts the required sheet, and transfers it to the gantry pickup position. This process runs automatically through PLC control, with no operator involvement in the retrieval sequence.
Model Configurations and Capacity
The HC-A series offers four standard configurations, each designed for different sheet sizes and production volumes:
| Model | Sheet Size (mm) | Layers | Max. Load (kg) | Applicable Sheet (mm) |
|---|---|---|---|---|
| HC-A3015-83 | 3000×1500 | 8 | 3000 | 3000×1500 |
| HC-A4015-85 | 4000×1500 | 8 | 5000 | 4000×2000 |
| HC-A4020-85 | 4000×2000 | 8 | 5000 | 6000×2000 |
| HC-A6020-105 | 6000×2000 | 10 | 5000 | 6000×2500 |
The number of storage towers can be customized—facilities with high material variety or large production volumes can add additional towers to expand inventory capacity without increasing the gantry or cart count.
Double-Sheet Prevention Technology
When sheets are stored in close proximity with oil films or protective coatings between them, two plates can adhere together. Loading a double sheet into a laser cutter causes nozzle collisions, focus errors, and potential damage to the cutting head. Herochu prevents this through a multi-stage separation sequence:
Z-Axis Micro-Flexing: The loading manipulator applies a controlled bending force to the sheet edge, breaking the vacuum seal and oil adhesion between stacked plates. This mechanical separation is the first line of defense against double-sheet pickup.
Compressed Air Injection: Precision nozzles direct air at 0.6 to 0.7 MPa into the gap between plates, forcing separation of sheets that resist mechanical flexing. The air pressure is calibrated to the material type and surface condition.
Thickness Verification: Electronic and mechanical thickness sensors measure the separated sheet to confirm single-plate isolation. If the sensor detects a thickness exceeding the programmed value—indicating a double sheet—the system pauses and alerts the operator before the gantry moves toward the laser bed.
Independent Vacuum Zone Control: Each vacuum cup on the loading array operates on an independent control circuit. When handling sheets with cutouts, holes, or irregular geometries, cups positioned over open areas automatically shut off to maintain vacuum integrity on the remaining contact points. This prevents pressure bleed that could cause sheet drops during transfer.
Material Flow and Transfer Cart Integration
The transfer cart bridges the storage tower and gantry loading zone, moving raw sheets from the tower output position to the gantry pickup point at speeds of 5 to 15 m/min. The cart operates on floor-mounted guide rails, with positioning sensors that ensure precise alignment with the gantry pickup station.
When the gantry completes a loading cycle, the cart returns to the storage tower to collect the next sheet in the production queue. This continuous circulation maintains a buffer of staged material, so the gantry never waits for the tower to complete a retrieval cycle.
Positioning Accuracy and Repeatability
The gantry loading arm achieves a positioning repeatability of ±2 mm across its full travel range. Horizontal movement spans 10 to 30 m/min, with Z-axis lifting at 5 to 10 m/min and fork adjustment at 5 to 20 m/min. The gantry structure uses a dual-girder composite truss design mounted on precision guidance rails, maintaining travel accuracy over long stroke lengths.
For laser cutting applications, this positioning accuracy ensures that every sheet lands on the cutting bed in the correct orientation and alignment—within the machine’s programmed coordinate system. Sheets requiring 90-degree rotation for longitudinal or transverse feeding are handled by a pneumatic orientation mechanism on the gantry.
Inventory Management and Material Tracking
The storage tower’s PLC controller maintains a real-time inventory of every tier—material grade, thickness, sheet dimensions, and quantity. When material levels drop below a preset threshold, the HMI alerts operators to replenish stock. Material is loaded into the tower by forklift or crane through designated loading positions, with each new sheet logged into the system by grade and thickness.
This inventory visibility eliminates the material search time that plagues conventional storage—operators no longer need to walk the storage area, identify the correct pallet, and verify material specifications before retrieving a sheet. The tower knows what it holds, where each sheet is located, and which one the next job requires.
Production Scaling and Customization
Herochu configures each laser automation loading unloading system to the specific production environment. Tower height adjusts to available ceiling clearance, tier count scales with material variety requirements, and the number of towers expands to match inventory volume. The gantry span and rail layout adapt to the physical constraints of the facility, with 3D layout planning conducted before installation to verify clearances, material flow paths, and integration points with existing laser cutting equipment.
For shops processing mixed material grades—carbon steel one shift, stainless the next, aluminum on weekends—the storage tower accommodates multiple materials across different tiers simultaneously. The PLC tracks which tier holds which grade and routes the correct sheet to the laser without cross-contamination between material types. This flexibility makes Herochu’s system practical for job shops that handle diverse workloads rather than dedicated single-material production lines.
