Unarco carton flow options for FIFO picking and pick modules
What Unarco carton flow is designed to solve
UNARCO carton flow is a gravity-fed rack approach for operations where cartons, cases, or totes need to move from a replenishment side to a picking face in a controlled first-in, first-out sequence. Buyers usually research this topic for a practical reason: they need to know which UNARCO carton flow option fits case picking, split-case picking, e-commerce fulfillment, or a multi-level pick module.
UNARCO offers several carton flow formats, including snap-in roller track shelves, welded shelf assemblies, full-width roller units, plastic wheel beds, low-profile solutions, and pick-face accessories. The right selection depends less on the product name alone and more on carton size variation, SKU velocity, lane depth, rack compatibility, replenishment method, and safety review.
For broader storage and handling context, see the material flow section.
How carton flow supports material flow in a warehouse
Carton flow rack is often described as flow-through rack because product is loaded from one side and picked from the other. Metal shelves, wheels, or rollers are set on a slight pitch so cartons advance by gravity toward the operator. The Material Handling Industry defines carton flow rack as a rack style suited to small-quantity case picking, using rollers or wheels to move product from the back of the rack to the front. It is commonly associated with FIFO inventory control, where the earliest loaded carton is presented first for picking.
This is different from static shelving. Static shelving can work well for slow movers or simple storage, but it usually requires more manual searching, facing, and walking. Carton flow creates a fixed forward pick position, while reserve inventory is fed from behind. In a well-slotted operation, that separation can reduce picker congestion because replenishment and picking do not have to happen in the same aisle at the same time.
UNARCO’s public product information emphasizes the same operating principles: gravity flow, SKU-dense applications, FIFO presentation, rear loading, front picking, and integration with conveyors or other storage systems. Those claims are consistent with how carton flow is typically used in pick modules, distribution centers, retail replenishment operations, and e-commerce environments where many SKUs need to remain visible and accessible.
Main Unarco carton flow options and where they fit
UNARCO does not present carton flow as one fixed product. Its product literature describes multiple formats for different duty levels, carton profiles, and installation preferences. The names are useful because they indicate different construction styles, but the application questions remain the same: what is being picked, how often is it replenished, and how much flexibility will the slot need over time?
| UNARCO option | General format | Typical use consideration |
|---|---|---|
| UPICK | Snap-in roller track, modular knock-down shelf design | Useful where modular shipping, field assembly, or later reconfiguration is important. |
| KPICK | Snap-in roller track with factory welded shelf construction | Relevant when a more prebuilt shelf format is preferred for carton flow bays. |
| RhinoTrac | Full-width carton flow roller lanes, commonly described with aluminum rollers | Suited to applications that need a broad roller surface rather than narrow individual track paths. |
| Dura-Flex | Plastic wheel full-bed roller style that drops into pallet rack | Appropriate where varied carton widths may make full-bed coverage useful. |
| D2 low-profile | Low-profile carton flow option with plastic wheels and a solid roller deck | Useful where shelf height, pick-face ergonomics, or dense vertical spacing matters. |
| RhinoDeck | Low-profile lighter-duty lane format | Often considered for lighter products or retrofit needs in existing carton flow layouts. |
| Tilt tray and knuckle shelf designs | Pick-face angle and presentation accessories | Used to improve carton presentation at the pick face when ergonomics and visibility are priorities. |
The practical difference between track-based and full-bed designs matters. Narrow roller tracks can be efficient when carton sizes are consistent and lane layouts are stable. Full-bed wheel or roller surfaces may offer more tolerance when carton widths vary or when slotting changes frequently. Low-profile designs can help when vertical opening space is limited, but they still require proper evaluation of carton weight, lane pitch, support, and rack beam arrangement.
Selection factors before specifying a system
A carton flow decision should start with the SKU profile, not the equipment catalog. If cartons have similar footprints and stable demand, dedicated lanes may provide clean organization and predictable replenishment. If carton sizes change often, a wheel-bed or full-width roller design may reduce the need to reposition lane dividers. If the operation handles both full-case and broken-case picking, the pick face may need dividers, label holders, tilt trays, or carton stops so individual items are easier to identify.
Carton size, weight, and bottom condition
Gravity flow depends on consistent contact between the carton and the wheel or roller surface. A rigid, flat-bottom carton may travel differently from a soft, bowed, damp, or damaged case. Lightweight cartons may need a different pitch than heavier cartons. Very heavy cartons may require added supports, impact zones, or a more robust roller configuration. For that reason, sample-case testing is valuable before a layout is finalized.
Lane depth and SKU velocity
Deep lanes make sense for high-volume SKUs that are replenished often. Slow-moving SKUs may waste cube if they are assigned long lanes that rarely empty. A common planning mistake is to apply the same lane depth across too many products. Better slotting separates fast, medium, and slow movers, then matches lane depth to replenishment frequency and pick demand.
Pick module integration
UNARCO describes carton flow as suitable for integration with conveyors, pallet rack, and pick modules. In a multi-level module, carton flow is not just storage; it becomes part of the work path. The design has to coordinate replenishment aisles, pick aisles, carton presentation, take-away conveyors, guardrails, stairs, fire protection review, and structural rack requirements. A carton flow shelf that performs well in a single bay still needs system-level review when it becomes part of a larger module.
Comparing carton flow with alternative rack types
Carton flow is strongest when the goal is forward picking from many SKUs. It is not automatically the right answer for every warehouse. Selective pallet rack is better for direct pallet access and bulk storage. Pallet flow is better when full pallets, rather than cartons, need FIFO movement. Push-back rack is typically used for denser pallet storage where last-in, first-out behavior is acceptable. Static shelving can remain cost-effective for low-velocity SKUs that do not justify a dedicated flow lane.
| Storage method | Best fit | Main limitation |
|---|---|---|
| Carton flow | Case, tote, and split-case picking with FIFO presentation | Requires good slotting discipline and compatible cartons. |
| Static shelving | Low-velocity hand-pick inventory | Can increase walking, searching, and manual facing. |
| Selective pallet rack | Direct pallet access and reserve storage | Less efficient for dense forward carton picking. |
| Pallet flow | FIFO movement of pallet loads | Designed around pallets rather than individual cartons. |
| Push-back rack | Dense pallet storage with LIFO behavior | Not suited to strict FIFO carton picking. |
The best layout often combines more than one storage type. Fast-moving each-pick items may sit in carton flow at the forward pick face, while reserve pallets are stored above or nearby in selective rack. Medium movers may use shallower carton flow lanes. Slow movers may remain on shelving. This mixed approach can protect capital spending while still improving order-picking consistency. See also: automation and controls.
Safety, standards, and engineering checks
Carton flow is simple in operating principle, but it is still part of a rack structure and should be reviewed accordingly. The Rack Manufacturers Institute identifies ANSI MH16.1-2023 as the current American National Standard for the design, testing, and utilization of industrial storage racks. That does not mean every user must read the full engineering standard before buying carton flow. It does mean rack design, load capacity, anchoring, repair, modification, and installation should be treated as engineering matters rather than informal warehouse changes.
OSHA’s warehousing guidance also emphasizes safe storage and handling practices, including keeping rack load capacities from being exceeded, maintaining safe aisle clearances, inspecting and maintaining shelving and racking, and isolating damaged areas. For carton flow, these principles are especially relevant at the load side, pick face, and any aisle where forklifts or pallet jacks operate near workers.
- Confirm the rack frame, beams, shelves, and flow components are rated for the intended loads.
- Check that carton stops, lane dividers, impact areas, and supports match the actual product profile.
- Maintain clear separation between replenishment traffic and picking traffic where the layout allows.
- Train workers not to overload lanes, climb rack, bypass stops, or use damaged components.
- Review any retrofit or rearrangement with a qualified rack professional, especially when changing beam elevations or load patterns.
Safety review should also include ergonomics. A flow lane that delivers product too low, too high, or too far from the operator can create unnecessary reaching. Tilt trays and knuckle shelf designs may help presentation, but they should be selected based on the actual pick motion and carton size rather than added as a generic accessory.
A practical evaluation checklist
Before choosing a UNARCO carton flow configuration, warehouse teams can use a structured checklist to reduce specification errors. The checklist should combine operational data, product samples, layout constraints, and engineering review.
- Build a SKU velocity profile. Separate fast, medium, and slow movers before assigning lane depths.
- Measure real cartons. Use actual carton length, width, height, weight, and bottom condition instead of relying only on item master data.
- Define the picking method. Clarify whether the operation is full-case, split-case, each-pick, batch-pick, zone-pick, or conveyor-fed.
- Test representative cartons. Gravity flow performance should be validated with the cartons that will actually run in the lane.
- Confirm rack compatibility. Existing pallet rack may need beam, depth, capacity, or anchoring review before retrofit.
- Plan replenishment. A good pick face can still fail if replenishment aisles, staging, and reserve storage are poorly organized.
- Document load limits and maintenance rules. Operators should know what each bay can hold and what damage must be reported.
This process gives buyers a stronger information base than simply asking which carton flow product is most popular. It also helps identify cases where carton flow may not be the best fit, such as unstable packaging, very low SKU movement, extreme carton weight variation, or layouts where replenishment and picking cannot be separated safely.
Frequently asked questions
Is Unarco carton flow the same as pallet flow?
No. Carton flow is generally used for cartons, cases, totes, or split-case picking at a forward pick face. Pallet flow is designed for pallet loads. Both can support FIFO inventory movement, but they operate at different load scales and require different lane components.
When is a full-bed carton flow surface better than roller track?
A full-bed wheel or roller surface can be useful when carton widths vary, when slotting changes often, or when cartons need broader bottom support. Roller track can be efficient for consistent cartons and stable lane layouts. The better choice depends on product testing and layout requirements.
Can carton flow be added to existing pallet rack?
Often it can, but the existing rack should be reviewed for dimensions, beam capacity, frame condition, anchoring, and the load pattern created by the carton flow shelves. A retrofit should not assume that any open pallet rack bay is automatically suitable.
Does carton flow guarantee higher picking productivity?
No system guarantees productivity by itself. Carton flow can support better SKU visibility, FIFO presentation, and reduced walking when it is correctly slotted and replenished. Poor slotting, inconsistent cartons, congestion, or weak replenishment discipline can reduce the benefit.
What is the most important planning step?
The most important step is matching the equipment to actual SKU behavior. Carton dimensions, weight, sales velocity, replenishment frequency, and pick method should drive the choice of UNARCO carton flow option, lane depth, and pick-face design.
Bottom line
UNARCO carton flow is best understood as a family of gravity-fed picking solutions rather than one universal rack product. UPICK, KPICK, RhinoTrac, Dura-Flex, D2 low-profile, RhinoDeck, and pick-face accessories each address different needs in case flow and split-case environments. The strongest projects begin with SKU data, real carton testing, rack compatibility review, and a clear understanding of how replenishment and picking will move through the space. When those inputs are handled carefully, carton flow can become a disciplined material flow tool rather than just another rack accessory.
