Vertical Carousel vs Vertical Lift Module (VLM)

How Each System Works

Vertical Carousels use a series of carriers (shelves) attached to a chain-driven loop that rotates vertically — like a Ferris wheel. The operator requests an item and the carousel rotates the nearest carrier to the access opening via the shortest path. Carousels excel at high-throughput picking with fast rotation speeds.

Vertical Lift Modules (VLMs) use an extractor mechanism (inserter/extractor) that travels vertically between two columns of trays. When an item is requested, the extractor pulls the tray from its column and delivers it to the access opening. VLMs dynamically measure each tray’s contents and adjust tray spacing for maximum density.

Side-by-Side Comparison

When to Choose a Vertical Carousel

Vertical carousels are the better choice when:

• Speed is critical — Carousels rotate continuously and deliver items faster than VLMs, especially in high-pick-rate environments
• Budget matters — Carousels typically cost 30-50% less than comparable VLMs
• Items are uniform size — Tires, wire reels, paint cans, garments, and other standardized items fit perfectly in fixed-height carriers
• Batch picking — Multiple orders can be picked in a single rotation cycle
• Heavy items — Carousel carriers handle heavy loads across the full carrier width

When to Choose a VLM

Vertical lift modules are the better choice when:

• Mixed-size inventory — VLMs dynamically adjust tray spacing to accommodate items of varying heights
• Maximum density is the goal — Dynamic tray spacing eliminates wasted vertical space between items
• Tall ceilings — VLMs can extend above 50′ to take advantage of extreme vertical space
• Dual access needed — VLMs can serve two operators on different floors simultaneously
• Clean room environments — Enclosed VLMs protect contents from dust and contamination