Warehouse Design – AutoStore
Posted on 18th July 2022
In the previous Blog - “Autonomous Mobile Robots - Cobots + Swarmbots”, the introduction stated that for a variety of reasons including:
availability of labour,
Covid safe methods of working,
increased online sales
that we will continue to see increased use of automation in warehouse operations.
We also stated that the picking operation in a warehouse generally accounts for more than 60% of the total labour hours, and as a result we are seeing highly efficient automated picking solutions including “Goods to Person” concepts becoming more popular. These concepts also go some way to segregating operators and adhering to social distancing requirements.
In the previous Blog we stated that Goods to Person systems reduce the non-value adding walking tasks associated with traditional trolley picking operations and picking rates are significantly higher. This is equally applicable for the AutoStore system, which is the subject of this Blog.
Note: as way of full disclosure, I have had the pleasure of visiting the Jacob Hatteland Computer Headquarters (now AutoStore Systems), Nedre Vats in Norway in 2015. The purpose of the visit was to see the manufacturing and design centre and to complete the Technical Design Training Course. This was a great experience and one I will never forget; they were great hosts and it was exciting to share their vision. As time has moved on it is great to see the technology and the robots develop, I am still highly impressed with the solution, and in the right application I think it is a great concept.
Since my visit in 2015 the number of worldwide installations of AutoStore has increased from 63 to 300 worldwide in 28 countries (figures correct as of 2019) and this figure will no doubt have increased since then.
The original robots were named Red Line. The Red line robots are now on version 5. Last year AutoStore developed the new Black Line robot. The Black Line robots are nimbler and carry the bins in a different way and offer increased performance over the Red Line robots. I will initially discuss the Red Line concept and then compare this to the new Black Line robots towards the end of this Blog.
I am sure that in each section of this Blog you will learn something new about this fascinating area of automation. As an independent consultant and I have no bias to any supplier or any solution, and I aim to review the equipment in a subjective and objective way.
How does AutoStore work?
The basic concept around AutoStore is that bins are stacked one on top of another within a grid. The bins are accessed from above by a robot. The robot moves around the grid on rails fitted on the section of the grid. The bins are lifted from the stacks and either repositioned on top of the grid awaiting the next move, or directed to one of the operator ports. If the required bin is not on the top of the stack the robots can also “dig” for bins with multiple robots lifting bins from the stack as required. Accessing a bin at the very lowest level could include up to 15 moves to access the bin and up to 3.5 minutes. If the stack is 24 bins deep, then the time to access the lowest level bin could be up to 7 minutes. Of course, the more digging required then the more robots are required.
At the ports warehouse operators perform the replenishment, inventory checking, and picking tasks.
A simple Google search will return numerous YouTube videos relating to AutoStore, and some of these will visually demonstrate how the robots operate.
The AutoStore promotional videos demonstrate how a traditional medium height shelving area could be stored in AutoStore, using in a quarter of the original footprint (as demonstrated on the next 2 pictures).
Equivalent AutoStore footprint
Future design concept in same footprint
This future design shows the same area now with 4 times the original storage capacity in the same footprint. The final image also shows 2 carousel ports used for loading into / picking from the stores.
WCS (Warehouse Control System) / WES (Warehouse Execution System) - the Control System
As with any robotised application in the background there is a control system. This system using a combination of logic and algorithms determines the most efficient way of utilising the equipment and maximising the efficiency of the overall operation.
The software is designing to:
Ensure availability of bins at the pick station – by accessing a bin at the lowest level of the stack it can take up to 7 minutes to access a bin, the software will schedule the sequence of bins to ensure picking is not interrupted due to delays
Minimise the amount of digging the robots complete
To where possible allow for stock to be depleted from bins to enable the bin to be filled with other products
Maximise efficiency of the robots, including planning in charging times
Batching of orders in line with picking strategies
Outside of an operating hour the robots will perform housekeeping tasks. The system will review which (stock keeping units) SKU’s are becoming popular and if required reposition them above slow movers within the stack.
During downtime stock taking tasks can be planned into the operation, also, low level count confirmations can be scheduled. It is easier, quicker and more accurate to count a 1 instead of a 10.
Also, some housekeeping could be scheduled with the relocation of items from one bin to another to release empty bins for further storage
The control system will interface to the client’s host system as required to confirm stock adjustments, picks completed, etc.
Bin Design – sizes / materials
Bins are stackable up to 5.4 meters in height (14 bin stack 425mm (TBC) 16 bin stack for 330mm and 24 bin stacks for 220mm). The installations will not be of mixed bin sizes.
The Autostore Bins 3 different sizes with a footprint of 649 x 449 mm (internal 601mm and 401mm) and heights of 220, 330 or 425 mm with a max bin weight 36 kg including bin (30kg of stock). The containers can be subdivided up to 32 compartments per container to increase the number of SKUs and inventory density.
The bins are injection moulded and can be made in different materials including HDPE, and anti-static PP-ESD. The bins can also be subdivided with compartments to store different SKU’s if required.
Note: the 425mm bins are only suitable for the new Black Line system.
AutoStore Bin fitted with dividers
In the UK George Utz Ltd supplies the majority of the AutoStore bins as they have had the tooling for many years, Schoeller Allibert also has access to the tooling and should be able to supply bins. The bins could be shipped from outside the UK, but this could prove to be a very expensive option.
Planning for Go Live
As part of any project plan careful consideration to the receipt and loading of bins into the store is essential. As the bins do not stack, there will need to be careful consideration about the initial intake of bins and scheduling the receipt from the suppliers.
As an example, Swisslog considers a small installation of Autostore as 40,000 bins. Assuming 4 footprints per pallet and the bins stacked 8 levels = 32 bins / pallet. If the store holds 40,000 bins this equals 1250 pallets. Assuming 26 pallets / load this equals 48 loads.
Swisslog Project Sizing
As with any goods to person picking solution the main efficiency gains result of eliminating nonvalue adding walking from the process. As with some of the other GTP applications we have seen there is also the opportunity with AutoStore applications to further enhance efficiency with the application of pick to light and light guided picking.
The tasks can be performed hands free which also offers improved pick efficiency when compared to other pick methodologies.
What you will find with some advanced solution designs is the inclusion of conveyors to and from the picking stations. The picker could also complete the packing operation at the port, but this will affect the picking performance but will reduce additional handling and delays.
Ports Positioned in a Tunnel
The different types of ports will be discussed in the next section of this Blog.
The AutoStore area can be created on floor surfaces which are not perfect, the structure can be adjusted to overcome imperfections, not like in a VNA operation where super flat floor levels are required.
AutoStore can be integrated with any external logistics system within the warehouse, it can be a dedicated self-contained autonomous area, or can be integrated to other areas of operation.
Conveyor ports integrated with a conveyor
The AutoStore area will not go above a max clear height of 6m (for bins and robots to operate in plus additional 2 metres for servicing and accessing the area. If for any reason a robot breaks down, they can be manually retrieved by an engineer using a specially designed access platform running on the rails.
Each AutoStore installation will include the following:
The grid containing the stacks of bins
Maintenance area for robots.
Each of these areas are covered in more details below.
The grid consists of aluminium frames and supports to store the bins. The frame also includes the rails that the robots move along on the top level. The maximum height of the storage structure is 6m and the maximum height of the system, including to the maintenance area, is 8m. The structural components are standardised modules, nothing is bespoke, the components are relatively simple to install and easy to connect.
Any designs should if possible, allow for future expansion. Typically, as order profiles change with time, and volumes increase this place additional demand in the area which can be planned into the initial design. The system is modular and with some planning could be extended whist still operating.
The stores can be designed around existing building columns and in nonrectangular shapes.
The final solution design should have spare capacity to allow for future growth, or increased SKU’s or more varied or order profiles.
Another key task required is calculating how many robots (and ports) are needed. AutoStore have developed their own simulation software, and the simulation of inbound receipts and order picking can be reproduced using real data. The control system functionality and any operating assumptions will be replicated as part of the simulation. The engineering team at each of the suppliers will have access to the simulation software and the capability to complete the required analysis.
The Red Line robots and appropriate ports will operate at rates of up to 350 order lines per hour per port.
The Red Line R5 Robot is shown below: note it has canopy design and cantilever bin lifting.
There are two types of battery recharge, one for each type of robot. The R5 (Red Line) robots carry out opportunity charging when they have free time. The system will guide them to a charging point as required. They can operate for about 20 hours out of a 24-hour day. The chargers will be strategically distributed at various points within the Grid.
The Black line robots swap their batteries, see the later section dedicated to the Black Line Robots.
The operators in the warehouse will receipt products into the store, pick products, or perform inventory checks using a port. There are different types of ports designed to handle different volumes of activity. The ports are equipped with safety screens and sensors to ensure that operators do not lose any fingers.
The Red Line features three different workstation ports:
The Carousel Port, a three-armed high-speed port
The Swing Port, a medium speed port, fitted with a rotating arm that presents one bin to the operator while a second bin is positioned to the opposite end of the arm.
The Conveyor Port, a simple conveyor belt to move the bins to the operators.
Any final design will be validated as part of the simulation exercise, the number of ports could be a limiting factor on capacity. If possible, consider fitting extra ports if the space is available.
Who are the UK Suppliers of Autostore?
In the UK AutoStore supply through partners and distributors. The largest supplier in terms of installations is Swisslog (now with over 170 installations worldwide). Dematic also have numerous UK installations. Element Logic has also extended their AutoStore services in the UK since 2018. They have over 100 installations across Europe, they have recently installed their first UK Autostore Operation in Desford.
Other Design Considerations
It is unlikely that all of the stock in a warehouse will be stored in the Autostore area, additional areas may be required for either
very fast-moving lines
very slow-moving lines
Also, separate receipt, packing or value adding processing areas may be required.
When planning the operation, you will need to consider what tasks take place when, and how the volumes associated with each task will be processed through each functional area including the AutoStore.
When planning the AutoStore area picking will usually be prioritised over other tasks due to the condensed time between order receipt and despatch. Inbound receipt tasks will be planned around picking. Operational plans should also allow for known peaks either by day, by week or special events such as Black Friday should be planned for.
As with any storage solution you will need to carefully consider the AutoStore bin utilisation. Many bins in the AutoStore will be part occupied. Another factor to consider is that the same SKU may be stored in numerous bins. The SKU may be subject to FIFO (First in First Out), FEFO (First Expiry First Out) or batch control rules.
If bins are subdivided, then this may present other issues around filling part full bins.
Comment: locating an Autostore installation in a 12-metre-high warehouse does not fully utilise the building height and can be considered as inefficient.
The main benefits of a system such as Autostore is the ability to sequence bins to a pick station at a rate of one every 2/3 seconds. To maximise the efficiency of the operation it is imperative the processes at the ports are lean. All task rates should be measured either using conventional time study techniques or MOST analysis (this will be the subject of a separate Blog at a later date). The operator’s performance should be measured against these rates to ensure that the operation if running at full capacity and to validate the rates.
The most effective method of picking will need to be considered, either using batch picking or discreet order picking methods. As previously mentioned, the picking operation can be supported with pick to light systems to further improve efficiency. It is very important to fully understand the processes associated with the ports as this will be a key assumption in the overall system design.
AutoStore Black Line
Black Line Robot B1
The B1 (Black Line) is the very latest innovation from Autostore. It is designed for higher throughput systems of up to 650 order lines per hour per port.
The Black Line features a new Robot B1, it is smaller and lighter than the red line robot. The bins are transported within a Cavity in the robot so can operate on a reduced footprint. The B1 Robot is fitted with an exchangeable Lithium-ion Battery Pack which can be changed in seconds. The robots have direct drive wheels and can accelerate faster than the R5 robots.
The black line also features a new port called Relay port, a modular workstation with a picking module and three to six buffer modules.
Black Line Relay port
The standard size bins and the new 425mm bin can be used in the Black Line AutoStore.
Black Line Grid
A modified “double-double” grid, with double tracks in both directions, permits the robots to pass side-by-side in both the x and y directions. Combined with the robot’s smaller footprint, the new grid can accept more robots and operate efficiently in high density configurations. The B1 robot is also compatible with AutoStore’s original “single-double” grid.
The Black Line option now offers even greater levels of performance, and how these will be applied to warehouse operations with even more efficient use of technology will be very interesting to monitor.
As with the Autonomous Mobile Robots, Cobots and Swarmbots discussed in my previous Blogs, the application of Autostore and other Goods to Person solutions facilitates highly efficient warehouse operations. As you might have gathered from my Blogs, I am excited by all of these technologies, however, there is a right time and place for each different solution.
Autostore installations typically have a 4-year payback and require a high capital investment. If you are considering using Autostore or any other form of automation in your operations then the analysis of the current operation and assessment of alternative concepts should be assessed by impartial, independent experts. Please do not hesitate to ask for any advice. I would be very happy to provide a quotation to provide any assistance required.
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