Vertical Automatic Storage System Single Stock

The concept of single stock inventory management—maintaining exactly one location for each material type and consuming directly from that location without intermediate handling—has long been a goal in lean manufacturing. However, sheet metal’s physical characteristics have historically made single stock impractical. Heavy loads, large dimensions, and the need for fork truck access have forced fabrication shops into multiple stocking locations, duplicate inventory, and inefficient material flow. Herochu has solved this problem with its Vertical Automatic Storage System Single Stock configuration, a purpose-built solution that enables true single-stock management for sheet metal fabrication.

The Herochu vertical automatic storage system single stock architecture centers on one fundamental principle: every sheet of every material grade, thickness, and surface finish has exactly one designated storage position within the vertical tower. When material arrives from the supplier, it goes directly into that position. When a production order requires that material, the system retrieves it from that same position. No secondary storage areas, no overflow racks, no temporary staging locations. This discipline forces accurate inventory tracking and eliminates the multiple-stock situations that inflate working capital and confuse production planning.

Model selection for single stock configurations typically favors higher layer counts and broader sheet size compatibility. The HC-A6020-105, with ten customizable layers and sheet capacity up to 6000x2000mm, provides the volume needed for comprehensive single-stock implementation in medium-to-large fabrication shops. The HC-A4020-85 offers eight layers with 4000x2000mm sheet capacity, suitable for smaller facilities or shops with narrower material variety. Both models maintain the core single-stock functionality of dedicated positions for each inventory SKU.

Layer count customization takes on special importance in the single stock configuration because each layer typically holds a different material type. A fabrication shop with 150 active material SKUs cannot implement single stock with an eight-layer tower unless each layer holds multiple SKUs—which defeats the single-stock principle. Therefore, Herochu engineers work closely with customers to determine the exact number of layers required based on their SKU count and expected growth. For shops with high SKU counts, the system can be expanded horizontally by installing multiple towers side by side, each tower serving as a single-stock repository for a specific material family.

Load capacity per layer in single stock applications defaults to 3T for the 3015 and 4015 models, and 5T for the 4020 and 6020 models. However, because single stock implies each layer holds only one material type, the per-layer load capacity must accommodate the maximum expected quantity of that material. A layer designated for 10mm thick mild steel plates might need 5T capacity to hold a full supplier lot, while a layer for 1mm aluminum might need only 1T capacity. Herochu offers graduated load capacities within the same tower, allowing heavier layers at the bottom and lighter layers above—an optimization that improves stability and reduces structural requirements.

Movement mode combines linear guide rail precision with chain drive power, as in other Herochu configurations. However, the single stock version includes enhanced positioning accuracy features. Because each sheet returns to the exact same position after every use, the system must maintain absolute positional repeatability over years of operation. Herochu achieves this through hardened linear guide rails with wiper seals, pre-tensioned chains with automatic lubrication, and absolute encoders that remember position even after power loss. Repeatability is specified at ±1mm horizontally and ±0.5mm vertically, meaning a sheet returned to storage lands within a millimeter of its previous location every time.

Transmission mode remains chain drive, selected for its combination of strength, reliability, and serviceability. In the single stock configuration, chain drive includes a tension monitoring system that alerts maintenance personnel when adjustment is required. This proactive maintenance approach prevents the gradual positioning drift that can occur with neglected chain drives, ensuring single-stock integrity over the system’s lifetime. Vertical lifting speed is 9 meters per minute, slightly slower than some competing systems but intentionally chosen to minimize sheet sway and maximize positioning accuracy.

Inlet and outlet speed at 12 meters per minute represents a throughput-conscious design choice. Faster speeds would increase the risk of sheet misalignment during transfer, potentially compromising the positional accuracy required for single-stock operation. The 12 m/min speed has been validated through extensive testing across sheet thicknesses from 0.5mm to 25mm, confirming that sheets of all common gauges transfer smoothly without edge damage or positional shift.

Plate support selection becomes critical in single stock applications because different material types often require different support surfaces. The optional selection feature allows fabrication shops to assign specific support types to specific layers. A layer storing electro-galvanized sheet might use felt supports to protect the coating. A layer storing hot-rolled plate might use roller supports for easy movement. A layer storing aluminum sheet might use brush supports to prevent scratching. The system’s control software tracks which support type is installed on each layer, ensuring that operators never store material on an incompatible surface.

The number of storage units in the single stock configuration equals the number of layers, with each unit holding exactly one material SKU. This one-to-one relationship simplifies inventory management considerably. The material tracking database needs only to know which SKU occupies which layer. When a new coil or sheet lot arrives, the operator scans the material barcode, the system verifies that the designated layer is empty, and the tower retrieves that layer for loading. No decisions about where to place material, no optimization algorithms, no risk of misplacement. Single stock eliminates the complexity that plagues shared-storage systems.

Integration with ERP and WMS platforms is particularly valuable in single stock implementations because the simplified inventory model enables real-time material requirement planning. When the ERP system releases a production order for parts requiring 10-gauge HRPO steel, it checks the single stock tower’s inventory level for that specific SKU. If sufficient quantity exists, the order proceeds. If not, the system automatically generates a purchase requisition. This closed-loop planning eliminates the safety stock that fabrication shops traditionally hold to compensate for inventory uncertainty, reducing working capital requirements significantly.

For fabrication shops currently operating with multiple stocking locations, the transition to Herochu Vertical Automatic Storage System Single Stock typically reveals substantial hidden inventory. When every sheet of a given material must be stored in one designated location, any sheets found elsewhere represent either miscounts or duplicate purchases. Shops implementing single stock often discover that their actual inventory levels are 15 to 25 percent lower than their records indicated—and that their purchasing patterns have been inflating orders to compensate. Correcting these discrepancies typically recovers working capital equal to the system’s purchase price within the first year of operation.

The Herochu single stock configuration also supports just-in-time delivery models. With accurate, real-time visibility into sheet inventory, fabrication shops can schedule supplier deliveries to arrive exactly when existing stock reaches reorder points. No need for weeks of safety stock to buffer against inventory uncertainty. The vertical automatic storage system provides the data accuracy and retrieval reliability that JIT requires, while the single stock principle provides the inventory discipline that JIT demands. Together, they enable sheet metal fabrication shops to operate with inventory levels that would have been unthinkable in a manually managed environment.