Pallet Shuttle System

High-density pallet storage is simply the concept of condensing pallet storage into a smaller warehousing footprint to maximize warehouse space. Simple right? Maybe yes, if you know the right questions to ask when choosing the system that is best for your needs.

Static options include:
  • Double-deep selective rack
  • Very narrow aisle (VNA) rack
  • Drive-in/Drive-thru racking
Dynamic storage solutions include:
  • Pallet flow rack
  • Push-back cart system
  • Automated shuttle systems

When looking at high-density pallet storage there are several popular choices in both the static and dynamic system categories. Available warehouse space, SKU volume and pallets per SKU are all key determinants for choosing one over the other, however, dynamic racking offers inherent benefits over its static system counterparts.

Benefits of Dynamic Rack:

  • Dense storage without sacrificing selectivity
  • Specialty warehousing equipment is not required in most applications

Dynamic pallet storage is an easy way to achieve the high-density storage solution that you need while reducing inventory handling and order processing costs. Pallet flow and automated shuttle systems can go very deep lane and offer first-in, first-out inventory rotation, particularly important for perishable and date sensitive product.

So what sets pallet flow and automated shuttle systems apart? Here are some important questions to ask to ensure that your capital expenditure is maximized to increase efficiencies, streamline processing and reduce overall inventory costs.

Split-Roller Pallet Flow Lane Mallard Manufacturing Automated Pallet Shuttle Lane

Important Questions to Ask Before Investing in High-Density Dynamic Storage

  1. Which system maximizes the time of the forklift operator?

Shuttles are optimized when they pick at least 5 pallets consecutively per lane at one time.  Anything less than that and picking efficiencies are lost in the time it takes to move the shuttle.

You can maximize your shuttle efficiency by assigning two shuttles per driver so that while one shuttle is indexing pallets in the lane the other can pick from a second lane… again, however, the cost of an additional shuttle per driver must be justified by volume.

Pallet flow rack the other hand, doesn’t require a shuttle to move from charge/load side to pick face. Once the pallets are loaded into the system, gravity takes over and flows the pallets to the pick face. The pick face is automatically replenished each time a pallet is picked, ensuring there is not driver downtime with this system.

  1. Is time on your side?

In other words, how long does it take to move a shuttle to a pick location vs the time that it takes to pick a pallet from pallet flow using a forklift or automated guided vehicle (AGV)?

Since the automated system requires moving and placing the shuttle within the lane, it takes roughly 1.5 times longer to complete a pallet pick vs using a standard lift truck or AGV from a pallet flow lane.

This ratio is why pallets per SKU must be a crucial factor is choosing between high-density systems. See Question 4 below for more on throughput.

  1. What system maintenance is required?

Any dynamic pallet storage system requires free movement of the shuttle, cart, wheels or rollers. So generally speaking, forklift operators should scan pallet loads for loose shrink wrap, broken or protruding nails and boards, etc. before placing the pallet in the lane. However, it is imperative for an automated shuttle lane to remain debris free to ensure the safe movement of not only a very expensive piece of equipment, but a heavy piece of equipment.

The shuttle itself also requires specific care:

  • Photo eyes must be cleaned monthly
  • Batteries must be charged and serviced/replaced
  • Shuttles designed for ambient warehousing climates are sensitive to moisture/fog
  • Shuttle wheels wear and must be replaced
  1. Comparing throughput rates… pallet flow or automated shuttle?

Some shuttle systems can achieve double the throughput with half the forklift operators than would be needed for a static rack application. However, because of the need to physically move the shuttle, you must have the order capacity per SKU to justify the automated system’s operating expenses.

Once your system is in place, if the need arises for increased throughput, additional shuttles must be added to handle the extra work.  Pallet flow doesn’t require any additional materials to increase throughput.

  1. Planning for future growth?

When we design a system, we ask about expected or anticipated growth and plan accordingly… but is that an economical approach when dealing with shuttles that cost upwards of $35K a piece? Business growth is always the goal, but a growth of 10% or 20% will require adding additional shuttles to handle the load thus offsetting some growth economies.

Here’s more on the benefits and considerations for pallet flow vs a shuttle system…

Pallet Flow Pros:
  • Cost effective in either deep or shallow-lane configurations
  • Maximum selectivity – unique SKU stored in each lane
  • Lower Installation and maintenance costs
  • Easily reconfigured for shifting inventory specs
  • Orderly & efficient separate aisle loading and unloading
  • Speed controllers maintain safe pallet speeds for inventory & worker safety
Shuttle Pros:
  • Maximum selectivity – unique SKU stored in each lane
  • Ideal for deep storage – 24-26 pallets deep
  • Best suited for high-turnover, low SKU inventory –20-100 SKUs
  • Fast pallet storage/retrieval
  • Increased productivity — freeing operators to work elsewhere while shuttle picks pallets
  • Utilizes vertical warehouse space most effectively due to limited required bay height
  • Efficient with LIFO or FIFO inventory management
Pallet Flow Limitations:
  • Requires warehouse personnel to load & pick
  • Requires separate load and pick aisles
  • Requires additional vertical clearance per each level to accommodate inclined rails
Shuttle Limitations:
  • Additional shuttles may be needed to handle increased demand or throughput at a cost of up to $35k each
  • Automated systems may require higher maintenance costs
  • Lane changes require moving the shuttle –decreasing productivity
  • Electricity costs for battery charging
  • Tall configurations require specialized fork truck equipment

Ultimately, warehouse management has several dependable, and efficient systems to choose from to maximize high-density order storage and processing operations. Each system offers benefits… if the right conditions are met. If interested in a dynamic solution, our gravity flow experts can help determine if pallet flow is the right solution for your high-volume order fulfillment needs. Our pallet flow lanes are highly customizable and can be installed in any warehousing climate. Just give us a call and we can look at the best options for your specific needs.

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