CONTENT FROM KÖRBER SUPPLY CHAIN BLOG | PUBLISHED DECEMBER 16, 2022
The Attabotics solution cleverly uses short & predictable response times in combination with the space below the storage area to enable efficient sequencing. Do you need your heavy product before the fragile ones? That would not be a problem with this solution.
So-called cube-storage systems have been in the automated material handling market for over ten years now. They are very popular and for good reasons. Cube-storage solutions are very compact, reasonably affordable and offer an efficiency increase in order fulfillment.
A cube-storage system typically has products stored in bins and those bins are stacked on top of each other in a metal structure. Robots drive on top of the grid (or, in some solutions, below the grid) to retrieve the bins. In most cases, if a bin somewhere in the middle of a stack is required, all bins on top of it are placed to the side by robots that“dig out” the required bin. This technology makes efficient logistics and order fulfillment possible in distribution centers, taking warehouse operations to another level.
A natural limit – storage-to-throughput ratio
All this works very well, up to a limit. That limit is defined by the “storage-to-throughput ratio”. The throughput of these systems is limited by the number of robots that fit on (or below) the storage and retrieval system. Use too many robots, and the operation will get congested.
In the last ten years, this limit has increased. In the beginning, the maximum throughput that could be achieved in a system storing 10.000 bins was around 600 to 700 bins per hour. For a system with 20.000 bins, that would be double, etcetera.
Smarter Warehouse management systems (WMS), or Warehouse Execution systems (WES), faster robots and better layouts have increased this limit significantly, but there is still a maximum that can be achieved. The only thing that could be done to reach beyond that is to make the cube system lower. That will increase the surface area to create more space for the robots to navigate the system with more efficiency.
In real-world and real-time terms, what do these numbers mean? Let’s assume an average bin holds 30 pieces. And that for each bin presented, you pick out two pieces. With an average of 8 hours of picking per day, this would equal 15 to 30 days of inventory in the system. Or a stock rotation of 10 to 20 times per year.
For many warehouse operations, this is more than enough. A lot of them will never be close to this limit.
Sometimes it needs to be faster, e.g. for e-commerce and groceries
In some cases, however, things just need to be faster. A lot faster. For example, in fast-moving consumer goods and (grocery-)retail. Also, in e-grocery there is a need for high-stock rotations. Two or three days of forward inventory are not exceptionally low in these warehouse operations.
Many of the so-called micro-fulfillment centers are operated with low inventory. Because these MFCs are close to the consumers, warehouse space is often at a premium. And with spreading inventory across multiple smaller locations, there is a risk that the total inventory goes up. To minimize these effects, micro-fulfillment centers are operated with a minimum of stock.
The alternative is to use a shuttle system. These are “classic” aisle-based solutions. Typically there is a shuttle on each level, in each aisle. With these automated storage and retrieval systems, higher stock rotations can be achieved. The downside of these ASRSs is that they are less flexible and less compact.
Storage and throughput are highly connected. If more throughput is required, another aisle will need to be built. That will also give more storage capacity, even if it is not needed. Furthermore, these shuttle systems need conveyor systems to connect storage with picking workstations. In high-throughput systems, these conveyors will become complicated and expensive.
The best of both worlds
What if it would be possible to get the performance of a shuttle with all the advantages of a robotic cube-storage solution? Canadian company Attabotics has come up with that solution.
Inspired by how leafcutter ants build their colonies, they created a true 3D storage and picking solution. In this solution, the robots do not only travel in two dimensions, but they can also move vertically. This gives them access to each bin without the need for digging. It also provides more space for the robots to drive above the system, below or in the vertical shafts. It also makes it possible to build taller systems without scarifying performance in the distribution centers. Because of this, the theoretical limit of storage vs. throughput is 5 to 10 times higher than most other cube storage systems.
At the same time, the solution has all of the same advantages for the logistics in warehouse operations. Storage and throughput can be scaled independently. The grid could be extended for more storage, or robots can be added for more throughput. Every robot can reach every bin and every workstation, so there is no single point of failure. And whilst it is not as dense as some other cube storage systems, it is still a very compact logistics automation solution, especially because it can be built taller. Furthermore, it does not need complicated and inflexible conveyor systems to connect workstations to the storage area.
Having direct access to every bin also delivers other advantages: firstly, it makes the system independent of the order profile. Cube storage systems depend on a certain pareto-curve (ABC curve). Ideally, 20% of the products will generate 80% of the throughput. If this curve becomes flatter, more digging will normally be required and, therefore, more robots. With the Attabotics solution, this is not the case. Every article can be accessed equally fast in the automated material handling system.
The direct access also makes the solution ideal for handling rush orders or other disturbances to the pre-planned workload.
As a final characteristic, the Attabotics solution cleverly uses short & predictable response times in combination with the space below the storage area to enable efficient sequencing. Do you need your heavy product before the fragile ones? That would not be a problem with this solution.
Take away and final insights – there is no one-size-fits-all
There is no one-size-fits-all solution. In many cases, standard cube storage solutions are a good solution for a warehouse. And in a 25m high building, a shuttle solution might be the most efficient.
But if you need high throughput in a small space, maximum flexibility and short response times – then the Attabotics solution should definitely be on your logistics shortlist.
Read the entire article here: https://www.koerber-supplychain.com/about-us/blog/meet-the-fast-3d-storage-solution-that-boosts-logistics/?utm_content=236048139&utm_medium=social&utm_source=linkedin&hss_channel=lcp-10806609