Advantages and Disadvantages of Automated Storage and Retrieval Systems (ASRS)
This article describes some of the most relevant advantages and disadvantages of using an automated storage and retrieval system (ASRS).
The global automated storage and retrieval system (ASRS) market has been growing at a fast pace in the past decade (8% growth annual average), helped by the rapid evolution in many of the technologies used. The industries that have experienced the fastest rate of ASRS adoption are food and beverage, retail, and automotive. In the coming years, the growth of e-Commerce and its increasingly automated platform will be another major factor driving the development of the ASRS market.
Figure 1. ASRS market size projections by end-user. Image used courtesy of KVB Research
ASRSs are one of the most effectual investments that can be made in a manufacturing or warehousing facility. Installing an ASRS to replace a traditional storage and product handling operation using forklifts significantly increases throughput, accuracy, and safety, while also reducing product damages and human error.
On the other hand, integrating an ASRS into a highly customized operation could be disadvantageous. Companies looking to invest in this technology must conduct a careful financial analysis, considering the relatively high initial costs.
Advantages of an Automated Storage and Retrieval System (ASRS)
A large number of manufacturing and warehousing facilities are affected by space limitations. These facilities are designed and built with certain considerations for immediate needs and some projected future growth. But frequently, as companies increase production and expand, storage needs begin to exceed the existing capacity. In these cases, continuing to grow horizontally by adding square footage to the building through construction can prove costly and, sometimes, impossible.
ASRSs are the most effective solution when it comes to increasing storage capacity vertically. In other words, ASRSs can achieve the highest level of volumetric efficiency or ratio of storage capacity versus square footage. For this reason, they are also commonly referred to as high-density warehouses.
Figure 2. A vertical storage carousel from Modula Inc. Image used courtesy of Swisso Storage
One great example of the space savings achieved is vertical lift modules (VLMs). VLMs are a type of ASRS that are very useful for picking operations. They can store small parts, semi-finished products, or spare parts and tools in a maintenance area. VLMs are highly modular and normally do not require any special construction considerations.
Better Safety of Operations
In an industrial environment, maneuvering a forklift remains one of the riskiest jobs. In the U.S., there are nearly 100 forklift-related fatalities each year and about another 20,000 severe injury cases.
Figure 3. Most common non-fatal accidents involving forklifts. Image used courtesy of Big Rentz
Load balancing on the forks is critical to avoid a turnover. Also, most forklifts weigh several thousand pounds and can cause serious harm when striking a person, even at very low speeds.
Installing an ASRS effectively eliminates all risks associated with mixed pedestrian and forklift traffic, as well as forklift operations. Most operator interventions required with an ASRS can be done using a graphical user interface (GUI) or human-machine interface (HMI).
In some cases, it may be required to enter the area of the moving equipment. For example, for maintenance or to attend to a major failure. For these situations, ASRS must be equipped with the required safety interlocks, lockout/tagout (LOTO), and other procedures must be followed. Even with these residual risks, ASRS are a much safer option against forklifts.
Increased Accuracy and Efficiency
Like any other automated system, ASRSs are programmed to execute repetitive tasks with high precision. Handling products with an ASRS greatly reduces damages usually caused by human error in handling products with a forklift or other means. Beyond reduced labor costs, less product waste is a cost savings factor often overlooked in the decision-making process of installing an ASRS.
Another important plus of an ASRS is the increased accuracy in handling product data. Practically all ASRS that are controlled by a warehouse control system (WCS) or warehouse management system (WMS) are enabled to transfer product tracking data automatically.
In a manual operation, an operator would need to use a handheld scanner or typing data into the system. This is prone to many inaccuracies since a strict process sequence usually needs to be followed. The high-level control applications (WCS or WMS) of ASRSs practically eliminate this risk.
Disadvantages of an Automated Storage and Retrieval System (ASRS)
Building an ASRS is a large and complex construction project. Also, in many cases, special materials and reinforcements are necessary for the structure to withstand the loads to be stored. This makes the ASRSs of today inaccessible for some businesses that could greatly benefit from them. Naturally, those companies who install these warehouses have completed analysis that corroborates the financial viability of the investment.
Figure 4. A large ASRS storage structure under construction. Image used courtesy of Frazier
The good news is that, as with many other automation solutions, hardware is getting more compact. There are now ASRS designs better suited for smaller spaces and less industrial settings. Many supermarket chains, pharmacies, and distribution centers are beginning to explore these technologies for e-Commerce and online order fulfillment (micro-fulfillment).
While ASRSs are modular and scalable, they are typically built to perform a single type of task. The automation moving inside the ASRS is rigid. For example, stacker cranes can only move in a certain way along each axis.
Also, storage location dimensions cannot be adjusted. Certainly, there can be storage locations of various sizes within an ASRS, but these are decided during the design phase.
Once the structure is built, it would be very costly to make changes. This could one day have a negative effect on a business that, for instance, introduced a new product that exceeds one or more of the constraints of the storage locations. This is why it is crucial that future projections of production volume and product lines are included in the equation when deciding on installing an ASRS.
As with any automated system, ASRSs have advantages and disadvantages. Some advantages include increased storage density, safer operations, and increased accuracy and efficiency. On the other hand, some disadvantages are high initial investments and inflexible tasks. From a business perspective, high initial investments can be a large downside, but keeping a safe operation is a top goal.
Do the advantages outweigh the disadvantages? Why or why not?