What Are Vertical Lift Modules and How Can They Fit Your Warehouse?

Vertical Lift Modules

As warehouse operations become more sophisticated, remaining competitive and meeting fluctuating consumer demands may require upgrading to more advanced technology. Automated storage and retrieval systems (AS/RS) can significantly increase the productivity of your business, playing an important role in supply chain optimization.

Traditional racking systems, such as selective pallet racks, are relatively inexpensive, common, and simple to install. However, they don’t offer the throughput efficiency, inventory management, or safety of modern automated systems.

What is a Vertical Lift Module?

A vertical lift module (VLM) is an automated storage and retrieval system that increases the efficiency of warehousing operations. A VLM consists of two enclosed vertical columns that store inventory items in trays.

An inserter/extractor, a mechanical device located in the center of the system, travels up and down between the columns to load and retrieve trays as needed. When an order picker requests a specific item using a computer interface, the inserter/extractor retrieves the tray containing the item and places it in a bay for retrieval.

This is distinct from a vertical carousel module, which uses a ferris-wheel-like rotating series of bins or trays to store and deliver goods for retrieval.

Is a VLM Right for Your Business?

To determine whether a VLM is a suitable addition to your warehouse and a worthwhile investment, you’ll need to evaluate your business needs. What storage or retrieval problems do you need to solve? For example, do you need to improve throughput and order-fulfillment efficiency? Do you want to reduce the risks associated with material handling? Is maximizing available storage space your priority?

While a VLM can be a highly cost-effective addition to your business, the initial capital outlay is high. As a result, you’ll need to calculate whether your expected ROI is worth the up-front cost of installing a VLM or whether an alternative AS/RS would be more suitable.

You also need to consider your warehouse layout and ceiling height. Horizontal carousels are more advantageous for warehouses with low ceiling heights but an abundance of horizontal floor space.

Staffing shortages

If you’re understaffed, unable to recruit suitably qualified personnel or want to reduce labor costs, automated technologies increase the efficiency of your existing labor force. Automated systems also require minimal training to operate effectively and do not require certification or a license.

Limited storage space

If you find that your warehouse has limited storage space to meet customer demands adequately. Traditional racking and shelving systems usually provide increased selectivity at the expense of storage density or vice versa. Automated systems can provide both without requiring you to compromise.

Maximizing available floor space also has critical safety implications. For example, the space between aisles in a warehouse that uses racking must be sufficient to allow for forklift truck drivers to safely complete the vehicle’s turning radius and maneuver to avoid obstacles. Due to a lack of space, forklift collisions are a common cause of rack damage. Automated systems significantly increase the space available for navigation.

Budgetary savings

While automated systems can be expensive to purchase and install, the long-term return on investment (ROI) can be significant, depending on the inventory items you store and distribute. Increases in worker productivity, picking accuracy, and reducing demand on forklift trucks can save money over time.

Determine your load capacities

Modern vertical lift module trays can support at least one short ton (2,000 lbs.). As a result, the technology provides the versatility needed for accessing goods that vary considerably in weight.

What Are the Advantages of a VLM?

Vertical lift modules have several advantages relative to other storage systems, from selective to carton-flow racking.

Vertical storage space

If your warehouse has limited horizontal floor space, you can use available vertical space by installing a VLM. The only limiting factor is the clear height (the distance from the floor to the lowest overhead object.)

A VLM has a compact footprint, allowing you to assign warehousing space to other tasks or processes.

Compact footprint

VLMs have a relatively compact footprint, so you can recover most of your warehouse’s floor space for other applications. Whether you need to increase the size of the shipping and receiving area or install low-tech shelving for other purposes, the space savings are considerable.

Alternatively, by using a VLM, you can lease a smaller warehouse, reducing rental costs. If you install a VLM in a factory, reducing the space needed for storage allows more space to be allocated to machines, assembly lines, welding stations, and other materials handling areas.

Increased productivity

One of the most significant advantages of an AS/RS is increased worker productivity. A VLM increases pick rates, reducing labor costs in the process. Because your workers spend less time picking items for distribution, they can be assigned to other tasks.

Alternatively, by installing a VLM, your labor requirements are reduced, thereby saving recruitment, training, and payroll costs. When workers perform repetitive order picking tasks, mistakes can happen.

Fortunately, AS/RS, including vertical lift modules, are designed to increase the accuracy of the picking process by several methods, such as a light-directed picking system. In pick-to-light, the tray has a sequence of LED lights that direct the worker to the item they need to pick, reducing search time.

Reduced workplace injury

In warehouses, workers are expected to locate and pick orders quickly to meet KPIs (key performance indicators). In addition to performing repetitive physical tasks, order picking duties often require the worker to kneel, crouch, lean forward at the waist, and reach to pick items from shelving or racking. A VLM delivers the goods in a tray to an ergonomically designed access window.

Depending on the design, the height of the tray may also be adjustable to further reduce the strain on the worker. When the worker retrieves the items, the access window closes, protecting both the operator and the goods. The shutter is connected to a sensor that will not close if it detects an obstruction, improving worker safety.

Another way that VLMs protect workers is by fully enclosing the items. Unlike conventional shelving and racking systems, items can’t fall, potentially causing injury and inventory losses.

Inventory protection against damage

As the VLM is a fully enclosed system in which the inserter/extractor interacts with trays, the risk of damage due to improper handling is minimized. Seismic forces and forklift collisions are also unlikely to damage the contents of the VLM, and structural collapse due to impact is highly unlikely.

Inventory protection against theft

The enclosed VLM design also provides certain advantages regarding security when compared with either traditional racking or horizontal carousel systems that use caging. To gain access to the trays inside the VLM, you need to activate the computer interface and select the items; therefore, you can control access electronically.

Inventory management

Modern warehouses use warehouse management software (WMS) systems to manage receiving, putaway, picking, distribution, and resupply. Vertical lift modules and other automated systems allow for easy integration with existing software systems to maximize efficiency.

VLMs automatically scan the height of the items in the tray to achieve optimal storage density in the system. A dynamic storage system, the VLM adjusts internal shelving height accordingly.


To increase throughput rates, VLMs and other automated systems use slotting, which stores the most commonly picked items in the same trays for efficient retrieval. The more items a worker can retrieve from the same tray before the VLM replaces it, the higher the throughput rate and overall productivity. The VLM stores these items closer to the access window, ensuring workers have less space to traverse to retrieve the items needed at the time.

Increased speed

Depending on several factors, such as the configuration of the VLM, the order profile, whether you need to retrieve a single order or a batch, VLMs can significantly increase the throughput rate.

Simple to operate

VLMs are relatively simple and intuitive to operate, minimizing training times. The worker can deliver all commands using a computer system adjacent to the access window.

Modula Vertical Lift Modules

Modula Vertical Lift Modules

Consider Modula VLM solutions to realize the benefits of automation for your warehouse or distribution center. Modula vertical lift modules can allow you to recover up to 90% of your business’ floor space and have several unique features. Units vary in height from 10’10” to more than 46’ — ideal for various ceiling heights and warehouse layouts.

Modula storage trays permit a maximum product height of 27.36” and range in width from 74.8–161.41” and depth from 25.75–33.74”. The trays also have net payload capacities of 551, 1,102, 1,653, and 2,182 lbs. As a result, you can select the tray dimensions and weight capacities suitable for your specific inventory requirements.

Modula VLMs have a throughput of up to 120 trays/hour, increasing the productivity of your warehouse considerably.

Find the Right Automated System for Your Warehouse

At Shelving + Rack Systems, Inc., we offer a variety of storage solutions, both low and high-tech, depending on the needs of your warehouse. Call us at (800) 589-7225, and we’ll help you find the perfect solution for your storage needs.