There are several varieties of stacker cranes available according to the goods to be handled: stacker cranes for pallets and those that work with lighter unit loads (e.g., boxes), also known as miniload AS/RS (automated storage and retrieval system). The main difference between them lies in the size of the stacker crane and the weight supported, as stacker cranes for pallets are much larger and robust than those for boxes.
In addition to the goods they handle, each type of stacker crane can be classified by its structure and, more specifically, the number of masts. The mast is the body of the stacker crane. It incorporates what’s known as the cradle, which comprises forks that support the unit load. Depending on the load dimensions or the desired operating speed, the stacker crane will be formed by one mast (single-mast) or by two (twin-mast).
The stacker crane moves along a bottom rail attached to the concrete floor slab and an upper guide rail fixed to the rack profiles. These are charged with stabilizing the stacker crane and absorbing lateral forces when inserting and removing goods from the racks.
All stacker cranes can operate 24/7 in temperatures as low as -22 °F. In order to operate in both cold storage and ambient temperature facilities, stacker cranes are equipped with a warehouse control system (WCS) that executes the movements indicated by the warehouse management system (WMS).
Available for both boxes and pallets, these machines are made up of a single mast and are designed to provide the utmost functionality and efficiency in installations with lighter loads.
Their structure consists of two vertical masts with a lifting cradle in the middle that’s used to access all the storage levels. These types of stacker cranes are more resistant and robust than the twin-mast variety, which makes them perfect for handling heavy loads. They also enable high throughput due to their to agility.
Choosing the right stacker crane for your warehouse is no easy task. There’s no rule of thumb, as each installation has its own quirks. Likewise, the different varieties of stacker cranes can be modified to provide a more personalized solution.
With this in mind, first, you need to be absolutely certain of your company’s needs and goals, the type of product to be stored (quantity, size, weight, number of SKUs, etc.), the type of material flows required, the warehouse layout, and your budget.
Then, we’ll be able to analyze the movements the different types of stacker cranes are able to execute, always according to the extraction system used. This will depend on:
Out of all the options, it’s important to assess which one will give you the most functional and cost-effective features, always striving to strike a balance.
Of course, the various types of stacker cranes can be adjusted and adapted to the demands of each warehouse. However, both the height and type of extraction system are conditioned by, among other factors, the depth and dimensions of the racks.
