3D Pallet-Shuttle-Mole ASRS: Features, Benefits and Applications

Automated Storage and Retrieval Systems (AS/RS) have been a game changer for the order fulfillment applications ever since they were introduced as a means of automating the storage and retrieval of inventory within a warehouse. The introduction of AS/RS not only led to a more efficient use of labor, but also of space, allowing operations to quickly become more productive and profitable.

Since it’s now been on the market for several decades, AS/RS no longer has the strong reputation as a disruptive piece of technology, especially when compared to some of the newer robotic options on the market today. That does not mean AS/RS is no longer innovative, or that it doesn’t have a role to play in modern order fulfillment. In fact, the technology underpinning AS/RS is constantly being iterated in order to make it even more powerful, flexible, and valuable!

One such recent innovation in AS/RS can be seen in the introduction of the 3D Mole, which allows shuttles to travel in three dimensions instead of just one or two dimensions. Let’s take a look at what a 3D Mole is! How can a 3D Mole be used, and what are the key benefits that the technology can bring to your operation?

Are you considering implementing an AS/RS in your order fulfillment operation? We can help you think through your options.

What is a 3D Mole AS/RS?

To understand what a 3D Mole AS/RS is, it is best to compare it against simpler 1D and 2D models.

1D Moles

A 1D Mole is a form of shuttle based AS/RS that is capable of moving in one dimension. Typically, this means that it travels back and forth down a single lane, where it deposits or retrieves inventory, usually in the form of pallets.

The 1D Mole runs in tracks built into the racking that allow the mole to move underneath/below the pallets as the pallets are supported on the opposite edges of the storage lane. The mole raises up from underneath to pick up the desired pallet off the edge supports of the rack. Then the mole is able to move the pallet to the next software specified position in the storage lane.

Through this method, the 1D Mole enables FIFO, FEFO, or LIFO inventory flow in a multi-deep pallet storage lane, where storage lanes can be arranged in 1 to N pallet deep lanes. The N can be up to 24 pallets deep or even deeper, and multiple levels of lanes can be built into the pallet racking to create extremely dense storage that takes advantage of the height of the facility.

Racks can be arranged back-to-back, which only allows for LIFO pallet flow, or racks can be installed in a manner that is accessible from both sides, which enables all material flow options (LIFO, FIFO, FEFO).

To access the many storage lanes that can be created within a multi-level deep lane pallet racking system, the 1D Mole is typically moved around from lane to lane using forklift equipment. The instructions for the 1D Mole are typically given to the 1D Mole via RF communications, and these instructions can be initiated by the forklift operator or can be computer initiated depending on the level of integration that makes sense for your operation.

The instructions consist of routines that are needed to support different outcomes required for the proper flow of the pallets, e.g., retrieve first pallet, retrieve first 3 pallets stored, move all pallets in the lane forward as far as possible, move each pallet dropped off forward as far as possible (put-away functionality), and other routines depending on what the operation requires.

The 1D Mole with supporting rack enables very high-density storage with minimal investment in equipment. The 1D Mole applications can be inventory storage as described with the racking systems, but also the 1D Mole can also be used in pallet buffering lanes or transport lanes using rail systems though this is less popular.

2D Moles

A 2D Mole, contrary to the 1D Mole, is capable of traveling in two dimensions. In addition to traveling back and forth down a lane, 2D Moles can travel between lanes autonomously. This means that a single piece of machinery (mole) is now capable of interacting with an even greater amount of inventory on a 2D plane in an autonomous manner as directed through RF communication.

This gain in functionality can lead to significant savings in terms of OPEX because no forklift operator is required to move the mole within the 2D plane created by the rack.
The 2D Mole has to wait far less on the forklifts for relocation as it can now cover the entire 2D plane of the rack system it is located in. Therefore the 2D Mole’s operation is more independent and less limited both in terms of pallets it has access to and available work tasks. The 2D Moles can roam with greater freedom and have a larger pool of work available without as much interaction with forklifts.

This translates into the 2D Moles having better utilization than 1D Moles and that they can work ahead of the forklifts. The forklifts don’t have to move the 2D Moles nearly as often as they did the 1D Moles and can increase their utilization and use their time more beneficially in moving pallets from the racking system to other areas such as into trucks or to dock staging spaces or vice versa, etc.

So, even the forklift operational productivity will increase significantly with 2D Moles versus 1D Moles.

With the 2D Moles, the system becomes more systematically integrated with less human interaction and direction… it is more automated. 2D Moles still get moved between levels by forklifts or by lifts as they cannot traverse 3D (vertically) without help from another machine. This leads us to the latest form in the evolution of the pallet mole AS/RS.

3D Moles

A 3D Mole, as you likely guessed, can travel in three dimensions. So, in addition to being able to travel back and forth down a lane like a 1D Mole, and between lanes like a 2D Mole, a 3D Mole can travel vertically between storage levels. This means that a 3D Mole can interact with the entirety of more complicated racking design. This provides a new level of spatial density and a whole other level of freedom of movement and autonomy for the mole.

Applications of 3D Moles

3D Moles make sense for operations across the throughput spectrum as a result of their inherent benefits. The technology is very flexible and can be leveraged in a number of different ways, including but not limited to:

1. Environmentally Controlled Storage

For operations that handle inventory which must be kept in environmentally controlled storage, AS/RS equipped with a 3D Mole can be extremely beneficial. That’s because these systems can operate in temperatures and conditions where humans can’t or simply don’t want to work… typically down to -20° Fahrenheit in cold storage for frozen goods. This can include refrigerated or frozen environments for grocery and biopharmaceuticals, as well as humid, high-heat situations, and other controlled environments not well suited for human operators.

2. Production Lines

Operations with production lines can leverage 3D Moles to effectively move product, parts, and inventory to the exact spot that it is needed within a facility. Rails, for example, can run throughout the facility. When the shuttle gets to a certain rail, the mole can disembark from the shuttle and travel along the rail to deliver the product where it is needed. This can be particularly helpful in production lines.

3. Staging, Buffering, and Sequencing

As long as the rail system is designed correctly, a 3D Mole can be leveraged for staging, buffering, and sequencing by ensuring that inventory is always placed in the right sequence. The system is also flexible enough to do this in a more efficient manner and without as many limitations as linear systems, while being much more forgiving. This is because limitations in terms of physical space and movement are not as strict with a 3D Mole as with linear systems.

The buffering applications can be from low to very high throughput and the number of moles can be scaled to an operation’s exact requirements. However, 2D Mole systems are very competitive with 3D Mole systems in very high throughput AS/RS systems with relatively low storage density required as workload balancing can usually be planned and executed through smart pallet put-away that enables balanced outbound workload across the storage levels. The 3D Mole still offers greater flexibility for dealing with workload balance.

Benefits of a 3D Mole

The 3D Moles address all 3 of the biggest business case points for order fulfillment operations today: Labor costs, labor availability, and service level enablement to increase customer satisfaction, retention, and brand loyalty.

1. Autonomous Capabilities

Because of how the 3D Mole is designed and built, it is capable of autonomous movement throughout all pallet storage positions. This can reduce your capital expenditure and allow for greater ROI per mole.

2. Easier Workload Balancing

Because any 3D Mole can move to any location in the rack, required work or tasks can be assigned optimally to the closest mole. This avoids situations common with 2D Moles where workload location density is not matching the workload capacity of the moles on that storage level, which can be more work than the 2D Mole capacity on that level (creating an overload situation that causes long wait times for needed inventory) or less work than the 2D Mole capacity on that level (underutilization of moles on that level).

3D Moles are modular and scalable so that moles are easily added across time as demand, and consequently workload, for pallet movement increases. This has the effect of minimizing CAPEX on the initial investment and spread across time to create a best-case cash flow stream (and faster return on investment).

This is particularly true in situations where the storage to throughput ratio is very high, i.e., where many pallets need to be stored but very few pallet movements per unit of time are required. This is because you can build very dense rack storage and only put in the number of 3D Moles needed to reach the low throughput.

3. Reclaiming Unused Vertical Space

3D Moles take advantage of vertical space that would otherwise go unused as they allow for reduced aisle space because no forklifts are required in the rack. Likewise, because forklifts are not required in the rack, the racking structure can be built much taller (40 to 120 feet) to maximize a facility’s total vertical cube.

On a related topic of facility height, the 3D Mole rack can be used in a rack supported building design to minimize building costs. This typically makes sense with facilities having clear heights 50 feet or greater.

Note: This break-even height is a generalization and the value changes depending on location as there are significant differences in land costs and building costs based on geography and market.

4. Reduced Labor Costs

3D Moles with a proper design take over the movement of pallets throughout the storage area traditionally performed by the forklifts and forklift operators, thereby eliminating much of the labor and reducing the forklift fleet significantly.

5. Reduced Forklift Travel

3D Moles with a proper design have P&D locations for forklift interfacing that minimize forklift travel and workload in the facility. 3D Moles reduce the forklift driver labor costs while easing availability constraints for skilled labor, which is a major problem in many areas as the e-commerce boom requires more and more work at the warehouse level within the supply chain and on a 24/7 basis.

On a related note, the reduced human interaction with machinery also reduces the chances of accidents and creates significant savings in workers comp claims.

Understanding Your Options

While leveraging 3D Mole AS/RS can be extremely powerful for many operations, they are not suitable for all businesses as there is a minimum labor savings, minimum facility storage heights, and other operational thresholds to be met. Facilities with exceptionally low throughputs-to-storage ratios, for example, may need to leverage different solutions to reach their goals, for example the 1D Mole, 2D Mole, Mid-Load AS/RS, or traditional aisle-changing AS/RS to name a few. Ultimately, the best option for you will depend on your current business realities as well as the goals you are trying to reach as your business grows.

A trusted systems integrator can guide you to the right solution and design the perfect system for your needs. Contact us today to speak with a member of the Conveyco Team.