Production lines depend on a steady flow of components, many of them heavy or bulky. When that flow breaks down, it can lead directly to chronic inefficiencies: operators waiting on parts, forklifts weaving through pedestrian traffic, pallets staged near the line “just in case,” and material handlers rushing to catch up.
This approach can get the job done. But it consumes floor space, adds unnecessary safety risk, and makes it difficult to achieve true just-in-time replenishment.
A different pattern is emerging in modern production environments. Instead of staging pallets around the line, a centrally located Vertical Lift Module (VLM) can manage heavy components in dense, organized storage. From there, robots, cranes, assisted extraction devices, or AMRs (or even well-designed carts) move totes directly to line-side supermarkets or workstations as needed.
This article explains how that architecture works in practice.
We’ll walk through the core principles of a VLM-based line-feeding hub with assisted extraction and AMR delivery, outline when this model makes sense, and provide practical guidance for moving from racks and forklifts to a more structured, automated approach.
An automated production line is a manufacturing system in which material movement, part delivery, and key handling steps are controlled by equipment and software rather than manual processes.
In traditional setups, components are stored in pallet racks or floor locations near the line and replenished by forklifts, tuggers, or carts. In an automated production environment, storage, retrieval, and delivery are structured through systems such as Vertical Lift Modules (VLMs), conveyors, robots, cranes, or autonomous mobile robots (AMRs).
The goal of a successful automated production line is not to remove people from the line, but to improve reliability, safety, and flow by reducing manual lifting, forklift traffic, and ad-hoc material staging, all while ensuring the right components arrive at the right station at the right time.
Line feeding is one of the clearest opportunities for system-level improvement in a manufacturing plant because the material flow is repetitive, predictable, and tightly tied to production output. Traditional, manual feeding processes approach can keep lines running, but they will introduce structural challenges:
A well-thought out VLM-based solution can directly address each one of these challenges. Heavy or bulky components are stored centrally in dense vertical storage rather than spread across floor racks. At the VLM, parts are delivered to an ergonomic access point.
From there, totes or trays move to the line using AMRs, structured cart routes, or other controlled transport methods.
The goal is not necessarily ultra-high-speed picking, as in e-commerce fulfillment, but core operational improvements that are relevant to just about production line: predictable replenishment, safer handling, and cleaner flow between storage and production.
Multiple technologies need to work together to make this production line automation model function as a true line-feeding hub.
A Vertical Lift Module manages heavy, bulky, or awkward components in a controlled vertical system rather than in pallet racks spread across the floor.
Components are stored in totes or directly on trays, depending on size and handling requirements. With appropriate tray configurations and load ratings, VLMs can accommodate heavier assemblies as well as longer or irregular parts that would otherwise require deep rack locations or custom shelving.
This approach is already common in industries handling demanding components.
For example, in oil and gas applications, long pipes and large mechanical parts are stored in automation-friendly systems that stage material in a structured way for downstream processes. Instead of forklifts retrieving items from scattered rack positions, parts are presented at a controlled access point and then transferred onward in a defined sequence.
This shift drives tangible operational benefits:
A VLM like the Kardex Shuttle can operate 24/7, achieve up to 600 picks per hour, and save up to 85% on floor space compared to traditional shelving. You can learn more about tapping into VLMs to boost production here.
When components approach or exceed comfortable lifting limits, the transfer point at the VLM becomes a more critical control point.
At the access opening, a robot on a track, an overhead crane, or a powered extraction device can pull individual parts, full totes, or trays from the VLM and position them for delivery.
This is especially important in environments where parts regularly exceed ergonomic thresholds (often around 40 pounds or more), and manual handling would introduce safety or compliance concerns.
In heavier industrial settings, the VLM can be designed with defined buffer or staging positions. A robot or crane places the tote in a stable handoff zone where an AMR or cart can safely retrieve it. This removes the most physically demanding motion from the process while keeping the overall flow structured. We take a deeper look at integrating pick and place robotics with common workflows like palletizing, replenishment, and order picking in this resource.
Importantly, robotics is not a required starting point. Many plants begin with powered lift-assist devices or controlled tray extraction systems that reduce strain without adding full robotic complexity. As volume grows or handling patterns stabilize, those assisted systems can evolve into fully robotic extraction where it delivers clear value.
You can learn more about how robotics can work with VLMs to revolutionize order fulfillment in this guide.
Once components are staged at the VLM, they still need to move to production in a controlled way. This is where autonomous mobile robots (AMRs) can fit naturally into an automated production line architecture.
AMRs pick up totes from defined handoff points near the VLM and deliver them to line-side supermarkets, individual workstations, or kitting cells. Routes are predefined, and tasks are triggered by production demand signals or min/max replenishment levels.
In practice, these AMRs replace repetitive forklift or cart runs with scheduled, predictable movement. In HVAC-style manufacturing environments, for example, heavier and larger components can be stored centrally in a VLM and then transported to production by AMR rather than by forklift weaving through pedestrian traffic.
This additional stage of automation drives some distinct operational benefits:
Production line automation is not a universal upgrade. It makes the most sense when material handling has become a structural constraint rather than an occasional inconvenience.
It is a strong fit when heavy or awkward components are used regularly at the line and must be replenished throughout the shift.
It becomes even more compelling when multiple lines or cells can share a centralized storage hub instead of each staging their own pallets.
Plants actively trying to reduce forklift traffic in pedestrian-heavy areas or limit manual lifting exposure often find that a VLM-centered architecture provides a practical path forward. A layout that supports defined AMR travel routes between storage and production further strengthens the case.
It may not be the first move when production volumes are low and line feeding is infrequent. If item dimensions vary widely and are difficult to fixture or standardize in trays, automation becomes more complex. Likewise, if cart-based delivery is currently meeting demand without safety or space pressure, the urgency for AMRs or robotic extraction may be limited.
Importantly, the architecture does not require every layer at once. Many facilities begin with a VLM managing heavy components and structured cart delivery to the line. That alone can reduce lifting strain, improve storage density, and organize flow. AMRs and robotic extraction can be added later as volumes grow or as labor and safety objectives evolve.
Designing an impactful VLM-based line-feeding system depends on careful attention to how material is packaged, moved, and signaled across the plant.
Before layout or automation is finalized, the container strategy needs to be defined.
Standardize on totes or containers that fit VLM trays efficiently and can move cleanly through every downstream step. The same container should be compatible with lift-assist devices, cranes, robots, or AMRs and make sense at the workstation. If operators have to immediately repackage or reorganize parts at the line, the system is misaligned.
Weight per tote must stay within defined ergonomic or mechanical limits. Even when robotics or cranes are involved, someone may still interact with the container. Delicate components require appropriate dunnage and protection so that vertical storage and transport do not introduce damage.
Labeling and identification strategies should also be settled early. Barcodes or RFID tags must remain readable throughout storage, transport, staging, and return. Clear ID discipline allows the VLM, AMR system, and production scheduling software to remain synchronized.
The VLM hub should be positioned to serve more than one line when possible. Central placement reduces redundant storage and shortens travel distances. At the same time, the area must safely accommodate crane motion, robotic extraction, or lift-assist devices if those are planned.
AMR traffic requires deliberate routing. Travel paths should avoid high-risk intersections with forklifts or heavy pedestrian zones. Defined pickup and drop-off points near the VLM eliminate ambiguity in handoffs.
At the line, staging should be structured. Designated spots for full totes prevent overflow accumulation near workstations. Just as important is the return path: empty totes must flow back to the VLM hub without relying on ad hoc manual returns. Closed-loop container movement keeps inventory visibility accurate and prevents drift.
A VLM-based line-feeding system depends on coordination between multiple control layers.
Production scheduling, MES, or ERP systems generate demand signals. The VLM inventory system manages storage locations and retrieval. The AMR fleet manager assigns transport tasks and routes. If robotic extraction is involved, a robot controller governs pick-and-place motion.
These systems do not need to launch fully integrated on day one. A practical starting point is simple replenishment logic: when line-side inventory hits a defined minimum, a task is triggered to retrieve and deliver the next tote. Basic API calls or message-based triggers can coordinate this flow. As the system matures, tighter integration with production sequencing and predictive demand can be added.
In some production environments, a VLM is not the only storage technology in play. While a Vertical Lift Module is often a strong fit for heavier, bulkier, or multi-size components, AutoStore can complement your setup by managing smaller parts in high-density cube storage.
This creates a practical zoning strategy: the VLM supports ergonomic access and controlled delivery of larger line-side materials, while AutoStore handles dense storage and fast retrieval of small parts used in just-in-time production support.
Most plants move in stages, building a foundation first and layering in automation where it delivers measurable value.
The first step is often straightforward: install a VLM as a centralized storage hub for heavy or frequently used components. The transport method remains familiar, but storage and retrieval are now controlled and consolidated.
Even without AMRs or robotics, this phase can deliver tangible improvements. Storage density increases by using vertical space, inventory becomes more traceable within the VLM system, and floor clutter near production is reduced because excessive pallets no longer need to be staged.
Once the VLM hub is stable, the next step is to address heavy handling and presentation at the line. Tray extraction devices, hoists, or lift-assist systems can be added at the VLM face to reduce strain during tote transfer. At production, defined line-side supermarkets or kanban racks replace informal pallet staging. Components are placed in consistent positions, making replenishment easier to manage.
This phase reduces manual lifting exposure and creates a more predictable material presentation at the workstation.
Only after flow patterns are stable and volumes are well understood does it make sense to evaluate AMRs or robotic extraction. AMRs can shuttle totes between the VLM hub and line-side supermarkets, replacing repetitive cart or tugger routes. Robot or crane systems at the VLM face can handle the heaviest, most repetitive transfers where ergonomic risk or staffing constraints justify the investment.
The most effective deployments start small (often with a single product family or line group). This allows performance to be measured and refined before expanding. Throughout all phases, a manual fallback process should remain defined. Structured automation works best when production continuity is protected, even if one layer of technology requires maintenance.
Safety is often one of the strongest drivers behind production line automation.
In many facilities, the business case for automation can be justified through its ergonomic benefits and risk reduction: lower injury rates, reduced workers’ compensation exposure, and improved compliance can justify investment even before throughput gains are factored in.
Production line automation makes the most sense when material handling has become a recurring constraint and source of unnecessary risk. Look at your operation in practical terms:
If several of these conditions are present, the constraint is likely embedded in the current material handling approach. In that case, a phased move toward a VLM-centered production line architecture is worth serious evaluation.
If several of these conditions are present, the constraint is likely embedded in the current material handling approach. In that case, a phased move toward a VLM-centered production line architecture is worth serious evaluation.
If you are evaluating production line automation, start with a clear picture of how material moves today.
Map your current line-feeding flows. Identify where parts are stored, how they are delivered, and how often replenishment occurs. Capture basic data such as part weights, delivery frequency, walking and driving paths, ceiling height, and potential locations for a centralized VLM hub.
With that information, Kardex can develop a concept design for a VLM-based line-feeding hub tailored to your plant. This design can include a manual cart-based approach, assisted extraction, AMRs, or robotic handling, depending on what fits your operation. You can also receive a phased roadmap outlining how to move from your current setup to a more structured, automated model.
Ready to modernize how you feed your production lines?
Share your current line-feeding process with a Kardex specialist, and we’ll help you explore a VLM-based hub with the right mix of people and automation for your plant.