Automated storage and retrieval system (AS/RS) for pallets designed to boost productivity and increase warehouse capacity.
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Stacker cranes are machines designed to store and retrieve pallets automatically. They move in length, height, and depth to load and unload goods from racking structures in a highly agile, precise manner.
Mecalux stacker cranes are equipped with state-of-the-art technology, significantly increasing warehouse productivity and maximising space utilisation to boost storage capacity. Moreover, they help reduce errors and risks associated with manual operations.
We’ve shortened the time spent on fulfilling and distributing each order
Mecalux stacker cranes are versatile storage solutions that cater to the needs of multiple companies. They have proven their effectiveness across numerous industrial sectors, including the food, metallurgy, automotive and pharmaceutical industries.
Automatic stacking cranes are an ideal solution for facilities with high-turnover SKUs and constant inflows and outflows.
Stacker cranes make optimal use of warehouse space, both vertically and horizontally.
These machines can operate in negative temperatures as low as -30 °C.
A stacker crane is a machine designed to perform 3 types of movements: longitudinal (to move along the aisle lengthwise), vertical (to operate at height) and transverse (for the forks to enter the racking depth-wise to deposit or remove pallets).
The conveyor next to the AS/RS brings the pallet to the end of the aisle.
The extraction system picks the pallet up and places it on the lifting cradle.
To transport the pallet to the location assigned by the WMS software, the stacker crane moves along the aisle in a simultaneous translational (lateral) and lifting motion.
The extraction system inserts the pallet into the racking to place it in the assigned location.
After storing the pallet, the stacker crane moves to another position to remove a pallet (in an operation known as a combined cycle).
The stacker crane moves towards the end of the aisle and places the pallet on the outgoing conveyor.
Automation has resulted in reduced logistics costs and more flexible production.
By automating our logistics centre, we’ve improved our throughput and responsiveness. We’ve also lowered operating costs and errors caused by manual management.
Automation has enabled us to enhance our storage capacity and safety, cut maintenance and personnel costs and rigorously monitor product movements.
During peak demand periods, we ship around 2,400 pallets a day. Automating our logistics operations has helped us shore up the increase in sales.
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See more case studiesMecalux’s single- and twin-mast automatic stacker cranes cover a broad spectrum of requirements. Thanks to this versatility, there is a suitable model for any load capacity, construction height and necessary cycle times.
Ideal for facilities up to 18 m tall and with few movements. It can work with single- and double-deep racking and the Pallet Shuttle system.
High-performance stacker crane for warehouses with high-volume inflows and outflows and up to 45 m tall. It is compatible with single- and double-deep racking and the Pallet Shuttle system.
Also recommended for facilities with high turnover. It differs from the single-mast model by offering greater load capacity in double-deep racking and can incorporate two lifting cradles.
Stacker crane up to 12 m high with an extraction system compatible only with the Pallet Shuttle.
Also known as an automatic trilateral stacker crane, this model is the simplest in the range. It is typically implemented to automate conventional racking up to 14 m high, previously operated using trilateral forklifts.
The design of stacker cranes for pallets minimises the forces transmitted to their supporting framework. This prevents damage to the AS/RS racking and structure in the long term.
A stacker crane is a fully automatic high-performance machine composed of various elements. These include masts, upper and lower guide bases, a lifting cradle, an extraction system and a hoisting mechanism.
The extraction system used will vary based on the application, the type of load to be handled, the arrangement of the racking and even the operational requirements. In general, there are 3 types: telescopic forks (single- and double-deep), the Pallet Shuttle and on-board conveyors.
Mecalux stacker cranes are fitted with a set of components designed to maximise the safety of the AS/RS.
Made of high-strength steel sheet metal, these constitute the stacker crane’s main axis. The lifting cradle, which supports the pallet, travels along the masts.
This moves loads vertically and performs storage and retrieval cycles through its extraction system.
Device with an AC motor that drives the lifting cradle in its vertical movement.
Box-shaped structure equipped with a drive wheel and a freewheel. It enables the stacker crane to move along the aisle longitudinally.
Ensures the stability of the stacker crane and dampens noise and vibrations resulting from its high-speed movement.
Aisles are outfitted with a bottom guide rail, top guide rail, safety equipment, electrical supply, data transmission and positioning systems.
Located next to the mast, this supplies the stacker crane with electrical power.
Component responsible for moving stacker cranes from one aisle to another in facilities requiring this operation. The stacker crane positions itself on the bridge, where it is anchored. Then, it moves laterally to the destination aisle, where the transfer takes place.
Alternative solution to the transfer bridge in which the stacker crane carries out the aisle-change manoeuvre by means of a railway-type switch.
This handling mechanism stores and retrieves pallets in single-deep racking.
This extraction system is employed for loading and unloading pallets in double-deep racking.
Autonomous shuttle car capable of lifting, moving and depositing pallets inside very long channels. The cradle is prepared to house the Pallet Shuttle and is equipped with motorised chains to transfer pallets from/to the incoming and outgoing conveyors.
Extraction system consisting of a platform with motorised rollers used in stacker cranes that feed pallet flow racking.
The cradle incorporates several safety elements: photocells (to verify maximum load dimensions, confirm empty locations and identify the exact position of the beams), load cells to detect excess weight, a system for checking fork and load centring, and a webcam.
The aisle features various safety elements, including the stacker crane’s safe speed control devices. Furthermore, hydraulic buffers positioned at the ends of the aisles are designed to absorb any potential impact from the stacker crane.
AS/RS stacker cranes are equipped with different safety devices to facilitate maintenance tasks. They include the cabin, anchorage points, lifeline to which the operator’s harness is attached when using the ladder, and maintenance platforms.
Perimeter fences delineate the stacker crane’s operating area, creating a protected space for AS/RS operations. Fall protection netting covers the sides of the racking adjacent to transit areas, preventing accidents resulting from falling goods.
Access doors and push-button pads allow safe entry into aisles for performing maintenance work. The push-button pad features a safety interlock position, and the aisle access procedure is carried out in accordance with the harmonised standard UNE-EN528.
These elements prevent people from entering through the pallet input/output points of the conveyor lines. The doors open only when a pallet enters or exits the AS/RS. The light curtains differentiate whether what passes through the access point is a load or a person.
This halts the operation of the stacker crane. It is activated using standardised push-buttons in the manual control positions and in specific areas of the AS/RS.
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Automated storage solutions
DownloadTechnological innovation for efficient warehousing
DownloadA stacker crane is a fully automatic machine designed to store and retrieve goods from locations within a racking system.
Automating a warehouse with pallet stacker cranes offers multiple benefits. Among them are increased productivity, safe and reliable operations, error elimination and optimisation of available space thanks to their ability to work at significant heights in extremely narrow aisles. Of course, the initial investment in automatic pallet racking solutions is higher than that of conventional storage systems. However, the increased operational capacity associated with automation and the reduction in operating costs (linked to handling equipment, for example) results in a rapid return on investment.
Mecalux stacker cranes can operate with single- or double-deep racking, pallet flow racking or the Automated Pallet Shuttle system.
Mecalux’s automatic trilateral stacker cranes enable the quick and cost-effective automation of adjustable pallet racking up to 14 m high. That is, these machines can be integrated into pallet racking that was previously operated with trilateral forklifts, all without modifying the racking structure. Automating other types of conventional storage systems, however, requires the replacement of the existing structures in the facility. Mecalux advises its clients on the design and implementation of the AS/RS that bests meets their needs.
Automatic stacking cranes for pallets are primarily used to move palletised loads in storage and retrieval operations. Additionally, Mecalux offers stacker cranes for boxes. Specially designed for miniload systems, these machines handle smaller unit loads such as boxes, trays and even tyres.
Mecalux stacker cranes are configured to operate in three different modes: automatic (the usual operating mode), semi-automatic (for specific and support operations) and manual (for maintenance work). The stacker crane’s automatic mode is used to execute the commands it receives from the WMS software. For instance, it performs storage and retrieval operations, storage position changes and self-learning of AS/RS locations in this mode.
This is not essential in all scenarios. For companies requiring a relatively low turnover of goods but a high storage capacity, one stacker crane could be shared by several aisles. In such cases, aisle-changing solutions (e.g., a curved-track system or a transfer bridge) can be installed to enable the stacker crane to operate in different aisles. Nevertheless, to maximise efficiency in an AS/RS, it’s ideal to use one stacker crane per aisle.
Yes. Stacker cranes incorporate regenerators that transform the energy generated during descent and deceleration manoeuvres into electricity. This electric energy is leveraged by other elements in the AS/RS, reducing power consumption.
Absolutely. In an AS/RS, access to areas where moving equipment (i.e., stacker cranes, conveyors, etc.) operates is appropriately restricted by wire mesh partitioning and secure access doors.
Yes. Every AS/RS requires two software programs. On the one hand, the warehouse management system (WMS) supervises and controls stock and assigns each unit load a location. On the other, the warehouse control system (WCS) is responsible for sending movement instructions to the stacker crane. Mecalux can supply both software programs.
Stacker cranes can operate at heights of up to 45 m.
The maximum load capacity of the stacker crane’s cradle is 1,500 kg for single-deep racking and 1,000 kg for double-deep rack configurations. Stacker crane models equipped with two cradles increase the load capacity to 3,000 kg (1,500 kg per cradle) in single-deep racks and 2,000 kg (1,000 kg per cradle) in double-deep racking.
Stacker cranes can move at a travel speed of up to 160 m/min.
The maximum lifting speed of a stacker crane is 66 m/min unloaded and 54 m/min loaded.
Mecalux stacker cranes can work in temperatures ranging from -30 °C to +40 °C.
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In the dynamic realm of warehousing, technology is ever-evolving to meet the sector's shifting needs. Stacker cranes once stood tall as pioneers, automating vast warehouses and transforming logistical challenges into streamlined processes. However, as the industry progresses, they are being eclipsed by a newer generation of innovations. This article explores the rise and evolution of stacker cranes, their inherent limitations, where they are still applicable, and how newer emerging technologies are reshaping the warehousing landscape.
Deep within the beginnings of automated warehousing, the stacker crane emerges as an example of early automation. Functioning primarily within automated storage and retrieval systems (AS/RS), these computer-driven giants were, for their time, efficient at navigating the expansive domains of warehouses, efficiently solving storage and retrieval conundrums.
In practice, a stacker crane is a machine designed for storing and retrieving goods in large warehouses or distribution centers. Imagine a tall, vertical structure that moves horizontally on rails and vertically along its mast. Attached to this mast is a carriage that slides up and down, equipped with mechanisms, often forks, to pick up or set down pallets or containers. The entire crane fits neatly within narrowly spaced storage aisles, allowing it to reach any shelf or storage point in its operational area. Think of it as a large robotic arm that can maneuver in both horizontal and vertical directions to access items throughout a storage facility.
Consider a large-scale e-commerce warehouse. It's the holiday season, and orders are pouring in by the minute. Here's a step-by-step scenario showcasing the role of the stacker crane:
1. Order Initiation: A customer places an order online for a toy, a book, and a pair of shoes. The order is processed in the warehouse's inventory management system.
2. Task Allocation: The warehouse's computer system receives the order and determines where each item is located. It sends instructions to the stacker crane to retrieve the items.
3. Navigation: Leveraging its in-built navigation system, the stacker crane swiftly moves along the designated path in the warehouse. Unlike human-driven forklifts, it can quickly calculate the most efficient route.
4. Height and Depth Adaptability: The toy is located on a high shelf, the book is midway, and the shoes are in a bin on the ground level. The stacker crane's telescopic mechanism allows it to adjust height with precision. It first extends upwards to grasp the toy, descends slightly to grab the book, and then goes further down to collect the shoes.
5. Item Retrieval: Employing its mechanical arms or magnetic systems, the stacker crane retrieves each item and places it in a designated tray or container attached to it.
6. Delivery to Packing Station: Once all items are collected, the crane transports them to a packing station. An operator or another automated system then takes over, packing the items for shipment.
7. Restocking: Once a shelf's inventory dips below a certain point, the warehouse management system can also instruct the stacker crane to restock items. The crane picks up goods from a receiving area and places them in the designated storage spots.
This might sound like a neat and efficient process. However, as is the case with all pioneering technologies, stacker cranes, despite their innovations, faced challenges as the industry evolved.
In warehouses back in the days, stacker cranes operated with remarkable precision compared to other systems, thanks to advanced computing systems guiding their movements. Gliding effortlessly along tracks, their dual-axis movement—vertical and horizontal—enabled them to access items regardless of their height. This meant the height of the warehouse was fully utilized, leading to improved storage densities.
The introduction of these cranes brought about a slew of benefits. Warehouses could now store more in less space, operations were expedited, and there was a significant reduction in errors commonly attributed to human oversight.
But, like all technologies, stacker cranes were not without flaws. Their reliance on intricate software made them vulnerable to system glitches, potentially stalling operations. Their track-bound movements sometimes led to logistical challenges in busier settings. Additionally, the hefty investment required for installation deterred smaller operations from adopting them.
These limitations suggested that while stacker cranes used to be a leap forward in warehousing, the industry was still on the brink of further evolutionary shifts to meet the limitations of stacker cranes.
Over the years, stacker cranes have undergone significant evolution to overcome their initial limitations and enhance their efficiency in warehousing and logistics operations. However, these advancements have been accompanied by persisting challenges, which have, in turn, driven the development of newer technologies.
Initially, stacker cranes were limited to operating one at a time within a single aisle. This constraint resulted in slower throughput and reduced the overall efficiency of the storage system. To address this challenge, modern stacker crane systems have evolved to allow for the deployment of multiple cranes within the same aisle. This technological advancement, often referred to as "twin" or "multishuttle" technology, enables several cranes to work concurrently in the same aisle.
Older stacker crane designs faced limitations in terms of storage depth, restricting access to only a limited number of storage positions within a single aisle. In response, modern stacker cranes have been developed with enhanced reach capabilities, facilitating access to deeper storage locations.
Historically, stacker cranes required relatively wide aisle dimensions to operate effectively, which reduced the overall storage density within a facility. Over time, innovations in stacker crane design have allowed for narrower aisle widths, known as "very narrow aisle" (VNA) configurations. These narrower aisles, often facilitated by guidance systems such as wire guidance or laser navigation, enable warehouses to make more efficient use of available space. However, even with this improvement, they still require four times more space compared to cube storage automated storage and retrieval.
Early stacker crane designs were limited in how high they could stack goods within a storage system, constraining the vertical utilization of warehouse space. To overcome this issue, modern stacker cranes have been engineered to reach greater heights, accommodating taller storage configurations. This increased construction height is pivotal for warehouses seeking to optimize vertical space utilization while maintaining accessibility to stored items.
While stacker cranes have evolved significantly to address their limitations, several challenges persist:
These persisting limitations have driven the warehousing industry to explore and develop alternative solutions that offer greater flexibility, higher efficiency, and improved cost-effectiveness. Newer technologies have emerged to address these challenges more comprehensively, ultimately taking over and reshaping the landscape of warehouse automation. While stacker cranes continue to play a role in certain contexts, the evolution of warehousing technology has been driven by the need to overcome these persistent limitations.
The recognized limitations of stacker cranes prompted the industry to pursue innovative solutions aligned with the multifaceted demands of contemporary warehousing.
The next generation of advanced warehouse technology is cube storage AS/RS (automated storage and retrieval system) pioneered by AutoStore. This has been another groundbreaking advancement in the history of warehouse automation technology. Due to the cube design, it delivers the most space-efficient solution in the market, which is cost-saving on many levels. Owing to the speed at which the robots can retrieve inventory Bins and deliver them to a workstation operated by a human, it is currently the fastest AS/RS per square foot in the market. This system also has a global uptime of 99,7%, which is a statistic that is extremely hard to beat for stacker cranes and other systems.
The cube storage AS/RS system also offers increased flexibility compared to traditional systems such as stacker cranes. Although referred to as a cube design, it doesn’t have to look like a 1x1 rubric cube. In fact, the storage Grid containing the inventory Bins, can easily fit around pillars, oddly shaped corners, and even on different floor levels. As long as the Robots have a path they can drive on top, and as long as the floor is flat, there is almost no limit as to how the AutoStore can fill every corner of the warehousing space. This is a huge advantage compared to traditional stacker cranes who need tall warehouses and at least 4x more space (thereby real estate costs) between shelves to allow the cranes to pass.
Moreover, since the products or SKUs are placed in several inventory Bins, even if a Robot was to break down, the product can simply accessed by another robot from another inventory Bin who would then take over. This means that there are no costly disruptions to operations and order fulfillment as could be found with stacker cranes and more traditional technologies.
To sum it up, it's evident that the traditional stacker cranes are not so suitable for supporting modern online order fulfillment, as that requires significantly higher speed, flexibility and system uptime.
One of the undebatable strengths of stacker cranes is their proficiency in handling weighty items. Their robust build allows them to lift and transport loads that many contemporary technologies might struggle with.
If leveraging a tall vertical space is more important than speed, especially if the goods are large and heavy, stacker cranes are still suitable.
In conclusion, while newer technologies are taking over with their innovative features, stacker cranes still carve out a niche for themselves in the modern industrial landscape. Their capability to handle heavy loads, makes them a viable choice for specific sectors within the industrial vertical. Businesses dealing with bulky items or keen on optimizing vertical storage might find stacker cranes not just relevant, but indispensable.
Warehousing has historically been a domain characterized by constant progress and adaptation. In earlier phases, the introduction of stacker cranes marked a significant milestone, pioneering the transition to automation and establishing foundational benchmarks for operational efficiency within the industry.
However, as global commerce evolves and supply chain complexities grow, the warehousing sector has been compelled to innovate further. The industry's dedication to optimization and efficiency has led to the development of a new suite of technologies. Building upon the lessons and insights gleaned from earlier systems like stacker cranes, these modern tools are intricately designed to cater to the multifaceted and ever-shifting needs of the global supply chain.
From software solutions offering real-time analytics to hardware systems enabling faster and more accurate product retrieval, these technologies signify the industry's commitment to staying ahead of logistical challenges. As global demands continue to evolve, the warehousing sector is well-positioned to adapt, leveraging these advancements to ensure a responsive and efficient infrastructure.
A stacker crane is an automated machine used for material handling in warehouses, primarily for the storage and retrieval of goods in racking systems.
Stacker cranes offer increased vertical storage efficiency, can lift heavy products, enhance safety compared to a manual warehouse, and minimize damage to goods.
Stacker cranes can be categorized based on their structure and functionality, including single-mast, double-mast, telescopic fork, and rotating fork variants.
In Automated Storage and Retrieval Systems (ASRS), a stacker crane is a component that automatically places and retrieves loads from specific storage locations, optimizing warehouse operations and vertical space utilization.