3 Types of Pallet Shuttle Systems: Which is Right for You?
Warehouse technology is constantly evolving to optimize supply chain efficiency. At the center of this push is automated storage and retrieval systems, and pallet shuttle systems are one of the core technologies in that genre of automation.
Warehouse pallet shuttle systems are ideal for boosting operational efficiency without increasing your facility’s footprint and likely increasing the storage density as pallet shuttles have similar aisleway width to VNA storage but with even more space efficient cross-aisles. Moreover, pallet shuttles offer the ability to increase automation on an incremental basis and expedite material handling processes—saving you time and money.
The question is: which type of pallet shuttle is right for your operation? Let’s explore the three core options, including their benefits, how they work, and when you should consider each type.
What Are Pallet Shuttle Systems?
Warehouse pallet shuttle systems play an ever increasing pivotal role in today’s warehousing industry. They are not just independently operating pallet shuttles, but they are the backbone of modern warehousing operations. Their primary role is to help your business reduce labor dependency problems and direct labor costs while also increasing storage capacity of your facilities and enabling you to respond quickly to customer demands.
These enhancements have become especially crucial with the rapid growth of e-commerce and widespread customer demand for same-day delivery for the direct-to-customer business channel but also increasingly the B2B business channel. Speed equates to value on your bottom line, and pallet shuttles make it easier to optimize your bottom line!
Some other factors driving warehouses toward automation include:
- Need for faster product turnarounds and availability while fighting transportation sparsity
- Increasing SKU diversity during a time of increased warehousing space costs
- Decreasing labor availability to the extent it hinders service levels and threatens market share against competitors in a highly competitive business environment
- Increasing operational costs due to high wages and shrinking labor supply making your facility capacities shrink and strangling your supply chain
Whatever your operational or efficiency goals, pallet shuttle systems can propel you toward meeting and exceeding them.
There are three main types of pallet shuttle systems. However, the foundational components of all three systems are the same. Every automated shuttle system consists of a rail system running through a multi-level storage racking system and a battery-powered intelligent pallet shuttle robot. The pallet shuttles glide along the rail to retrieve and store pallets as they directed by either a forklift operator in the case of 1D pallet shuttle systems or by Warehouse Execution System (WES) (aka Inventory Management System [IMS]) teamed with Robot Management System [RMS] (aka Robot Traffic Management System), responsible for route optimization and traffic control) for 2D (typically just WES/IMS and does not require RMS) and 3D pallet shuttle (typically requires both WES for task creation, task prioritization, and task release timing PLUS RMS for route optimization and real time traffic decision making).
Here’s an overview of the three types of pallet shuttle systems to consider for your warehouse.
Traditional 1D Shuttle Systems
A 1D pallet shuttle, often referred to as a “single-lane pallet shuttle,” is a material handling automation device used in warehousing and storage facilities where multi-deep storage is accessed by forklift equipment. This warehouse shuttle system retrieves palletized goods within a storage rack system with multi-deep lanes and is designed to work in a single-lane rack configuration, which means that it operates in a single lane and gets moved via forklift or pallet ASRS.
1D pallet shuttles and 2D and 3D pallet shuttles, can run 24/7 with minimal downtime. 1D shuttles do depend on either forklift operators using GUIs to direct movement or depend on ASRS pallet cranes with WES direction to get pallet movement tasks. They also offer space savings, allowing you to achieve more with less. They are ideal for use in tight areas where demand levels do not justify more advanced automation investment. 1D shuttles reduce manual tasks and therefore labor requirements, reducing the need for a large workforce.
2D Pallet Shuttle Systems
While 1D shuttle systems can only operate along a single path of movement back and forth down a storage channel (aka depthwise), the 2D shuttle systems move automatically both horizontally between storage channels and depthwise within the rack structure, meaning it moves itself automatically between storage channels in the racking system in most 2D systems. However, there are some 2D systems that stay within a specific storage level and aisleway. But the shuttles will climb on and off a shuttle carrier that transports what is commonly called a mole.
The mole enters storage channels to place and remove the pallets. The 2D shuttles that are captive to a storage level and aisleway are able to access multiple deep pallets in the storage rack. They are good for high turnover (short storage time) systems with high pallet movement per hour in and out per aisle rates.
The 2D pallet shuttle that can move between storage aisles and storage channels are more flexible and typically preferred for this reason. These 2D pallet shuttles systems that travel between aisles are less flexible than 3D systems. 3D pallet shuttles travel not only within the 2D storage planes but also use lifts or ramps to travel between storage levels.
The 2D warehouse shuttle system offers greater flexibility without manual involvement and storage capacity gains as main travel veins in the 2D pallet storage system usually fall in the range of 5’-6”, similar to VNA aisleways in space consumption, but layered on vertical storage levels and captive within a particular vertical storage level. They require a series of horizontal rails on the XY horizontal plane, which are affixed to your storage racks, providing versatility that allows them to navigate within the 2D horizontal storage racking planes of the racking system with ease. The 2D planes interact with vertical lifts to drop off outbound pallets from their storage level and pick-up put-away pallets assigned to storage locations on their storage level.
The biggest benefit of 2D shuttle systems is their versatility. They are perfect for high churn, low pallet storage operations and even more where visibility to outbound retrieval foresight can be used to load balance. This is based on outbound pallet retrieval visibility to balance outbound workload during the put-away process.
One key decision criteria for being able to use a 2D pallet shuttle versus a 3D pallet shuttle is this forward visibility and foresight to outbound allocations of pallets for next step/process retrieval requirements.
The 2D shuttle systems are ideal for fast turnover (short pallet storage cycle times) buffering systems where low storage to throughput ratios exist and where future visibility to outbound retrieval allows the Warehouse Execution System (WES) software or Inventory Management System (IMS) to balance the outbound workload. By properly assigning inbound put-away pallets to the buffer system and storage levels since pallet shuttles cannot move between levels.
All pallet shuttle systems, including 2D shuttles, have a modular design but have different limitations on shuttle movement. This means you can scale the system up or down based on the needs of your warehouse. This means the solution is a good fit for a warehouse with complex rack structures or variable inventory sizes and depends tremendously on outbound visibility as it impacts workload balancing when retrieval is required.
3D Pallet Shuttle Systems
3D pallet shuttle systems are the most advanced shuttle-based automated storage and retrieval solution. They offer the most flexibility as shuttles can move to any level and any location. They operate along three dimensions and offer ample versatility.
Unlike 1D or 2D, a 3D pallet shuttle is designed to move in three dimensions: horizontally, depthwise, and vertically via lifts or ramps. As such, they offer the highest degree of flexibility and storage optimization with the lesser need for outbound visibility for workload balancing to eliminate bottlenecks by only having a certain amount of 2D pallet shuttles on a storage level. Using built-in sensors, these 3D shuttles are able to position loads intelligently, minimizing the risk of damage to equipment and staff injuries. Note that some 2D shuttles also have such sensors.
With the ability to utilize integrated lifts to go up and down ramps between storage levels, the 3D pallet shuttles are ideal when outbound retrieval visibility is limited so that load balancing cannot be considered during put-away of pallets to the levels of the storage racking.
You should consider 3D shuttles if you have complex and varied rack structures. Also, it is very critical to select 3D shuttles if you are unable to have foresight into outbound retrievals by trailer or by need so that the WES or IMS software can put-away pallets. The workload can be balanced for the outbound retrieval process through strategic put-away of inbound pallets to the storage buffer.
In short, 3D pallet shuttle systems are particularly beneficial when used in operations where retrieval visibility is limited, and the software is unable to put-away strategically to balance outbound retrieval workload. Also, in the case that you have very few SKUs and many pallets stored, this scenario reduces the need of using a 3D over 2D system. This may become insignificant if the ratio of pallets stored per SKU is high enough that ample supply of each SKU for outbound assignment is available, making workload balancing between storage levels for outbound pallet assignment possible and fairly unconstrained.
How to Choose an Automated Warehouse Shuttle System
Any decision-making process should begin with an assessment of your warehouse needs considering the flow of goods, storage density, outbound visibility, and inventory turnover rates. You should also assess your throughput, the frequency of full pallet orders, and the intricacy of your racking structures.
When you start searching for a warehouse pallet shuttle system, your list of needs and operational parameters can serve as a checklist to RightFIT your best solution.
For instance, if you want to maximize vertical space utilization and minimize direct labor requirements, a 2D or 3D pallet shuttle would be the best option for your warehouse. Conversely, if you are tight on space and have a standard rack system and limited budget, a 1D shuttle would likely be the most pragmatic solution.
It’s essential to use the RightFIT seven step methodology to help determine where you stand before deciding on a warehouse shuttle system. Some factors you should consider include:
- Throughput and scalability: Your choice should align with your current needs and provide enough scalability for future growth.
- Full pallet orders: Ensure that your shuttle system can handle bulk efficiently, considering the orders that comprise an entire pallet of goods.
- Layer picking: If your warehouse uses layer picking to streamline operations ensure your shuttle system supports that function.
- Space constraints and layout: The size and layout of your warehouse will significantly influence your decision.
- Integration with existing systems: Most shuttle systems boast easy integration, but you might need to tweak the layout of your warehouse
- Forward/outbound retrieval pallet requirements: 3D pallet shuttles will be favored over 2D shuttle systems if SKU counts ratio to stored pallets is high and/or outbound pallet demand is not known at put-away so strategic put-away routines can be invoked. If the SKU count to pallets stored ratio is low and/or if outbound pallet assignment foresight is amply available, then both 2D and 3D pallet shuttle systems are feasible solutions for your project.
A lot goes into choosing a warehouse pallet shuttle system, and it is a decision that shouldn’t be taken lightly. So make sure to do your due diligence and reap the expected benefits of warehouse automation technology by utilizing Conveyco’s RightFIT seven step methodology.
Making the Final Decision
The warehouse shuttle system you implement will have lasting impacts on your business, so choose carefully.
Enlisting the services of an experienced order fulfillment and warehouse automation systems integrator can aid in finding the right solution for your business. Even if you are confident in your internal team’s ability to evaluate various pallet shuttle systems, gaining an outside perspective is extremely valuable to the future growth of your business.
Investing in automated storage and retrieval systems will pave the way for true warehouse optimization. Schedule a consultation with Conveyco to start your warehouse automation journey.
