Case Study: Smoother Carton Flow with ZPA & Inline Box Conveyors
How a regional distribution center reduced product damage and stabilized throughput using GlobalRoll inline box and zero-pressure accumulation systems.
A regional distribution center struggled with inconsistent carton flow, back-pressure damage, and frequent manual intervention around key machines. By replacing aging conveyors with GlobalRoll Inline Box and Zero-Pressure Accumulation (ZPA) systems, the facility significantly reduced damage, stabilized flow into print-and-apply and sorters, and created a layout that can scale with growth.
Key Highlights:
- Reduced product damage at key accumulation points
- Stabilized feeding into print-and-apply and sortation systems
- Improved operator ergonomics and reduced manual “babysitting” of the line
- Built a standardized line design ready to replicate in future facilities
About the Facility
The customer is a regional distribution center handling cartonized consumer goods. Orders are picked, packed, labeled, and sorted into outbound lanes for shipping to retail locations across the region. The facility runs multiple shifts and needs steady, predictable flow at its print-and-apply and sortation systems.
The Problems They Were Facing
Back-Pressure Damage
Legacy conveyors allowed cartons to “pile up” against stopped products, causing scuffing, crushed corners, and label damage—especially at accumulation points.
Inconsistent Flow into Automation
The print-and-apply system and downstream sorter received product in surges rather than a steady stream. This led to jams, mislabels, and frequent manual clearing.
Operator Firefighting
Operators had to constantly intervene—pulling cartons off the line, freeing jams, and manually spacing product—just to keep things moving.
Difficult to Scale
Because the existing layout was largely improvised, it was hard to plan expansions or replicate the design at another site.
GlobalRoll’s Conveyor Solution
Inline Box Conveyor System
GlobalRoll supplied an Inline Box Conveyor System as the backbone of the line—providing high-throughput carton handling from packing to sortation. Straight sections, curves, and merges were configured from standardized modules based on carton dimensions, speeds, and the building layout.
Zero-Pressure Accumulation (ZPA)
Zero-Pressure Accumulation zones were added ahead of the print-and-apply, weigh scales, and sortation infeed. Each zone is individually controlled to maintain gaps between cartons, ensuring that products never contact each other while queued.
Integrated Flow and Controls
The inline box and ZPA systems were integrated under a common control strategy, matching speeds and release logic to the capabilities of downstream equipment. Sensors and zone logic ensure controlled filling and emptying of buffer zones.
Implementation and Rollout
The project was executed in phases to minimize downtime:
Phase 1 – Layout & Design
GlobalRoll and the customer’s engineering team mapped the existing flows, identified pain points, and designed a new layout using standard inline box and ZPA modules.
Phase 2 – Installation
New conveyors were installed in stages, keeping critical operations running. Old sections were removed as new modules came online.
Phase 3 – Tuning & Training
Speeds, zone logic, and release rules were tuned while operators were trained on how the new accumulation and merge behaviors work.
Measured Improvements
Product Damage Down
Carton and label damage at accumulation points dropped significantly because cartons no longer contact each other under pressure.
Stable Flow to Automation
The print-and-apply and sorter now receive a steady, controlled stream of cartons. Machine utilization improved and unplanned stops decreased.
Less Manual Intervention
Operators spend far less time clearing jams or manually spacing cartons and more time focusing on value-added tasks.
Design Ready to Replicate
Because the line is built from GlobalRoll templates, the design can be reused—with minor adjustments—in future buildings or expansions.
Systems Used in This Project
- Inline Box Conveyor System – High-throughput carton handling from pack area to sortation.
- Zero-Pressure Accumulation Conveyor System (ZPA) – Controlled buffering ahead of automation and merge points.
Looking to Fix Your Carton Flow?
If you’re dealing with back-pressure damage, inconsistent flow into automation, or constant firefighting around accumulation zones, GlobalRoll can help. We’ll review your current layout and recommend inline box and ZPA configurations based on proven product templates.