Vertical Lift Modules (VLMs) are enclosed, column-based automated storage and retrieval systems in which one or more extractors shuttle trays between storage levels and an ergonomic operator bay; they are classified by unit footprint (slim vs standard), tray payload band, delivery configuration (single vs dual bay), and software tier [S1][S2].
The global installed base is dominated by manufacturers with multi-decade track records — Modula alone reports more than 20,000 clients worldwide and 70+ dealers across North America, with stated 25% year-over-year growth over the past five years [S3]. The category sits inside the broader vertical lift module family, alongside carousels, horizontal carousels, and cube-based shuttle systems.
How VLMs are classified by architecture
VLMs are split by enclosure type: fully enclosed "bin-style" columns that protect stored parts from dust and unauthorized access, versus open-front designs used in heavier-duty or external-bay integrations [S1].
Within the enclosed class, the dominant split is between standard and slim footprints. Modula's two current production lines — Modula Lift (the "most popular" line with single-tray payload up to 990 kg and max throughput up to 120 trays/hour) and Modula Slim (a compact, dynamic-tray-height design for low-ceiling or floor-constrained sites) — represent the two textbook architectural forks spec engineers compare [S1][S2]. A third announced line, "Modula Next," is positioned as a new-generation lift module with the highest performance tier in the catalog, although the source page does not publish a numeric spec sheet [S2].
Classification is also driven by bay topology: internal bay (the extractor delivers into a bay built into the unit envelope — the right answer when floor plate is scarce) versus external bay (the tray is delivered to a separate workstation that can be fitted with cranes, manipulators, or pick-to-light towers) [S1].
Unit-height, payload, and throughput envelopes
Unit heights of 3,300–16,100 mm cover the bulk of the commercial VLM envelope, allowing a VLM to be specified inside both single-story workshops and tall industrial bays [S1].
Payload tiers run from light-duty parts (tools, instruments, fasteners) up to a per-tray maximum of 990 kg on the standard Modula Lift, which is the published single-tray ceiling in the 2025-08 product sheet [S1]. Throughput is bounded at up to 120 trays per hour per extractor under typical picking duty cycles [S1].
Footprint recovery — the headline value proposition — is published as up to 90% of floor space reclaimed versus static shelving, and one VLM unit is stated to replace over 300 m² of conventional shelving footprint [S1]. A second published metric is the 2–3× picking-efficiency multiplier against manual rack picking, with 100% picking accuracy claimed when the integrated visual-picking aids are deployed [S1].
Single vs dual delivery: the throughput decision
Single-delivery bays are specified for low-to-medium throughput duty where one tray at a time is acceptable, because the extractor cycle time fully gates the operator's next pick [S1].
Dual-delivery bays are the higher-throughput class: while the operator is picking from the first presented tray, the second tray in the queue is being indexed into the pick position, which is the mechanism that pushes duty cycle toward the 120 trays/hour ceiling [S1]. Dual delivery is most often paired with an external bay and a pick-to-light or laser tower, because that is where the indexing time can be hidden behind human pick motion [S1].
Spec selection rule of thumb from the product sheet: if peak pick demand exceeds roughly half the rated single-extractor throughput, switch the bay topology from single to dual before adding a second extractor or a second unit [S1].
Payload options, access control, and software tier
Tray payload is selectable per tray width, which lets a VLM hold a mix of light and heavy SKUs in the same column without overbuilding the structure [S1].
Access control is granular: each operator can be limited to a defined tray set via user authentication, which is the standard mechanism for segregating high-value or regulated parts (tooling, calibration kits, controlled substances) inside a shared VLM [S1]. All pick and refill events are logged, giving full traceability for inventory and audit purposes [S1].
Software tiers divide into WMS Base (bundled free for life with any Modula unit purchase, aimed at small or growing footprints) and WMS Premium (end-to-end inventory plus warehouse management for larger operations), with ERP/SAP/Oracle/Microsoft/MRP hooks at both levels [S1]. For sites with broader materials-handling automation, the same VLM can be specified to feed or be fed by an AMR fleet or a shuttle system, and a VLM with a vertical envelope is often the only way to add capacity without expanding a building's forklift aisle footprint.
Use-case fit and limitations
VLMs fit best where SKU count is high, individual pick quantity is small, and items are picked frequently — the classic MRO/spare-parts, electronics kitting, pharmaceutical, and automotive aftermarket profiles [S1][S3]. End-user references published in 2026 from the manufacturer cite aerospace spares (Dassault Falcon Jet), medical-device production (Innomed, GF Machining Solutions), automotive aftermarket parts (Walser BMW), and fragrance R&D labs (Symrise) as running production on VLMs [S3].
VLMs are a poor fit where the dominant operation is full-pallet in/out (use a vertical lift module adjacent to a min-load ASRS instead), where stored items exceed the per-tray payload ceiling, or where ceiling height is below the minimum 3,300 mm unit envelope [S1]. Open-floor greenfield sites with cheap land may also fail the ROI gate, because the 90% floor-recovery advantage only monetizes when floor plate is the binding constraint.
Manufacturer sourcing signals (2026-07)
The category has at least three named production lines from a single major Western manufacturer with US production: Modula Lift (standard, up to 990 kg/tray, 3,300–16,100 mm unit height, 120 trays/hour), Modula Slim (compact low-ceiling variant), and Modula Next (announced new-generation, no published numeric spec at the time of the 2026-07 Asia product page) [S1][S2][S3]. North American distribution runs through 70+ dealers out of US manufacturing [S3].
Trackable signals to watch in the second half of 2026: a published numeric spec sheet for the Modula Next line, slim-model payload expansions (current slim product pages do not publish a per-tray ceiling comparable to the 990 kg figure on the standard line), and the rollout of WMS Premium as a bundled rather than licensed option [S2][S1].
The underlying component specifications are covered under linear module, and relay module.