Modern conveyor systems and automated vehicle solutions each have their respective pros and cons. So, which factors you should consider when choosing between these technologies? We spoke with the experts below to examine this question and more:
How should a business choose between AGVs/AMRs and conveyors? What factors determine the best fit?
Bernd Krebs (Stöcklin Logistik): It is primarily the quantity of goods that need to be moved that determines whether an AGV can perform at all. However, the choice also depends on whether the customer wants to block the space with a conveyor system or be more flexible.
Tim Mark (Creform Technik): The main factors are flexibility, throughput performance, scalability, as well as resilience and cost efficiency.
“The quantity of goods to be moved determines whether an AGV can perform at all”
Niels Buylinckx (Nipper): Flexibility, capacity, and site conditions are the key factors. On flexibility, production processes change, so AGVs give customers the highest degree of flexibility. At Nipper, all our customers receive training so they can create or change pallet positions [in the AGV’s software] themselves, providing them with even more flexibility.
As for capacity, if the output is 80 pallets an hour per production line, a conveyor will often be a better solution as conveyors handle such high throughputs more easily.
Finally, with site conditions, in heavy industries where floor conditions are rough and it might be dirty, these environments point more towards conveyors. But if there’s a need for a compact and safe solution to work in an open and accessible space, where people and other traffic operate, this would point move towards AGVs.
However, it’s not always a question of conveyor or AGV. In many cases we’ve provided a solution with a combination of conveying modules and AGVs. For example, by adding a u-shaped conveyor as an interface we are able to easy integrate the Nipper with our existing conveyors.
Otsuji Yuichi (Nakanishi Metal Works Co.,Ltd.): It depends on the customer's specifications and environment.
Can you describe a project where a conveyor system was a better fit than AGVs/AMRs?
Yuichi: In the case of one application with a quick cycle time, where the customer was moving goods from station A to B, a conveyor was the lower cost approach. This is because the AGVs would have needed to move the goods from A to B, and then come back to station A, meaning more vehicles would have been needed and more expense.
Buylinckx: The project where conveyors were the better fit was a site with very dusty conditions, no staff or vehicles occupying the same space, high capacities, and pallet buffer positions outside the building.
Krebs: At Basel Airport our client Swissport needed to move approximately 200 pallets per hour, which had to be picked up at the same time. This was not feasible with AGVs.
What about the opposite — when were AGVs/AMRs more suitable than conveyors?
Mark: If the user wants to start with a low transport capacity and then expand it at a later stage, AGVs should be used. For example, we have a customer that implemented a high-bay warehouse for workbenches, from which the pre-picked workbenches are retrieved using conveyor belts and then transferred to an AGV. At the beginning of the project, ten drop-off points were defined with an AGV to see how the concept worked. Now, since the current expansion, approximately 150 drop-off points are supplied with four AGVs. The implementation has been spread over approximately three years.
“To maximize the amount and availability of floorspace, and to have the highest flexibility of pallet positions … AGVs were a better fit”
Krebs: At Früh Packaging Company, AGVs were the best fit due to the project’s long transport routes and the need to move goods between several buildings and floors.
Buylinckx: In one project we offered three scenarios to transport pallets to a packaging line: conveyors, pallet shuttles, and AGVs. To maximize the amount and availability of floorspace, and to have the highest flexibility of pallet positions, plus scalability, AGVs were a better fit.
Are there specific applications (use cases) for which one technology is a better choice than the other? If so, which and why?
Buylinckx: Our AGV is well suited to manned spaces, so having different traffic around is not a problem. In industries such as brick manufacturing or where odd sized products are being manufactured though, conveyors are often a better solution.
Yuichi: If installation has to be done quickly, AGVs can be installed in a shorter period of time. Also, if there are forklifts in operation, conveyors cut off aisles and cannot coexist with these vehicles, so they are not a good fit.
If payloads are larger and/or need to be moved longer distances, automated vehicles (AGVs/AMRs) are the more logical choice.
Krebs: If the available traffic routes are to be used together with other participants – like manual forklifts and pedestrians – then AGVs are best, even automatic cleaning systems such as the Cleanfix.
What is the biggest challenge when deciding between conveyors and AGVs?
Krebs: As mentioned, it depends on the desired conveying capacity and how feasible it is within the facility. Environmental factors - such as ambient temperature, direct or indirect sunlight (which can dazzle the vehicle’s safety or navigation laser), ground conditions, conductivity, inclines or declines, and outdoor use - also play a major role, as does the type of unit loads to be transported.
“If installation has to be done quickly, AGVs can be installed in a shorter period of time”
Mark: The greatest challenge lies with the customer, as they have to define the requirements and the desired target state in advance. The customer has the task of defining all the framework conditions, such as weights, cycle times, layout, infrastructure, etc. The more precise the customer's specifications or ideas are, the faster and more accurately the project can be scaled, and a solution offered.
Buylinckx: AGV technology is still new and relatively unknown to many potential customers, who are more used to conveyors. However, by demonstrating the AGV by means of a Proof-of-Concept project they can witness the benefits in their own factory and processes.
When automating an existing facility (a ‘brownfield’ site), is there a clear favorite between these two technologies?
Krebs: No, it always depends on the individual case.
Mark: When it comes to automating an existing warehouse, there is no clear favorite. It depends on the customer’s requirements and how automation can be implemented during their ongoing operations.
Buylinckx: There is no clear favorite.
Yuichi: In my experience, no customer chooses conveyors to automate their existing warehouse. It is easier for customers to consider replacing their current transport systems with an AGV.
What about when building a new facility (a ‘greenfield’ site) - is there a clear favorite in that case?
Buylinckx: No, it all comes down to the customers’ expectations and the product flows required in their operation. Together we look how we can add value to the process or save costs.
Mark: When building a new warehouse, it is important to know which material is to be stored and retrieved and at what throughput. Accordingly, one possible solution can be to equip the warehouse with conveyor systems, which then transfer the material to be conveyed to an AGV in a centralized manner. Here, too, there is no clear favorite.
Krebs: No, it always depends on the individual case.
Is there a clear favorite in manufacturing environments?
Mark: In production environments, the AGV is favored, since it can be integrated into the environment and flexibly adapted without lots of construction.
Buylinckx: In manufacturing plants there is more and more demand for flexibility and floor space, thus AGVs.
Yuichi: No, there is not a clear favorite.
“AGVs are much more flexible and usually quicker and easier to implement and, depending on the size of the system, also cheaper”
Have you noticed any particular trend regarding the adoption of these solutions?
Buylinckx: The reason why we started with the Nipper AGV is that customers need flexibility in their use of floorspace, which is only increasing.
Krebs: The trend is moving more and more towards automation and flexibility. AGVs are much more flexible, usually quicker and easier to implement and, depending on the size of the system, also cheaper. If a change is to be made in the conveyor system, this usually involves much more effort.
Mark: We wouldn’t speak of a trend yet, but many customers are asking about the possible use of AGVs.
Yuichi: More and more customers are choosing AGVs. Customers without technology choose AGVs, because they allow easy course changes, rather than fixed equipment such as conveyors.
How does the process of system design and installation compare between conveyor systems and AGVs/AMRs?
Krebs: The AGV is designed, set up and commissioned more quickly than a conveyor system.
Mark: With conveyor systems, everything has to be specified in advance and on-site adaptation involves a great deal of effort.
Buylinckx: Of course, conveyors are fixed versus AGVs being very flexible and scalable. In practice though, a pallet will follow the same routes and process flows.
“For very small plants, the conveyor system is likely to be cheaper; for medium to larger plants, the AGV will be more cost-effective”
Yuichi: Since conveyors themselves are designed according to the customer's specific site, a lot of time is needed for design, manufacturing, and installation. Of course, this costs.
How do AGVs and conveyors typically compare on price?
Mark: It is quite difficult to compare prices. This is because an AGV already entails a basic price, which then pays off in relation to the functionality and the distance to be covered. For short distances and a high conveying capacity however, the AGV is usually more expensive.
Yuichi: AGVs are customized to a customer’s specifications, but the base design is the same as the standard. Most customizations are software modifications, so costs can be kept down.
Buylinckx: Conveyors are generally designed and installed for one particular flow. For another flow you’ll need another conveyor. With the AGV and its fleet manager, you can program many different tasks such as moving raw materials, packaging materials, transporting between stations, moving waste, finished goods and more. With the AGV in 24-hour operation we’ve seen an ROI of 13 months.
Krebs: It always depends on the size of the plant. For very small plants, the conveyor system is likely to be cheaper; for medium to larger plants, the AGV will be more cost-effective.
Lastly, can you imagine a day when mobile robotic solutions completely replace conveyors?
Buylinckx: Yes, and we also fly to the moon and beyond! But in parcel distribution centers smart conveyors will be more efficient…
NKC: No, I can't. Neither system is perfect. What’s important is to build a system that matches the needs of the customer and the surrounding environment.
Mark: We can’t imagine a complete replacement of conveyor belts by AGVs. There are too many applications that rule out the use of AGVs simply because of the high capacity to be conveyed.
Krebs: I think both are needed, now and in the future.
Summary: Which is best for your business – AGVs/AMRs or conveyors?
When it comes to modern warehousing and production environments, there is no one simple answer to the question of “conveyors or AGVs”. However, our experts did agree on several takeaways, providing you a solid starting point for any assessment:
- When a high throughput of materials is required, fast-flowing conveyors are the obvious choice.
- However, if flexibility and scalability are key, AGVs are a better fit.
- If materials need transporting across larger areas, or if other vehicles and people need to work around alongside the materials being moved, AGVs are the best choice.
- In terms of site conditions, automated vehicles are easily the most demanding of the two technologies because they require smooth, relatively clean floors and limited inclines.
- From a cost perspective, the two technologies are difficult to compare accurately, since AGVs are bought in a relatively ‘off the shelf’ manner compared to custom-designed conveyor systems. Generally speaking, however, for smaller sites conveyors are often the more cost-effective option, while AGVs better suit medium and larger sized sites.
- AGVs are more straightforward to install (especially AGVs and AMRs driven by ANT natural navigation, which require only minimal infrastructure changes).
Although AGVs are not expected to replace conveyors any time soon, they do appear to be trending more strongly.
As ever though, it is crucial to carefully define your organization’s current and future requirements to ensure you make the right choice.