LMJ’s editor Roberto Priolo looks at the most common issues related to lean automation, introducing this special feature, which includes two case studies.
Of the many debates heating up the lean community my favourite is the one on the relationship between lean and technology. While some will be sceptical about using automation in a lean environment, others will be interested in hearing how technology can support a lean transformation (perhaps recognising the role of innovation in today’s world).
There are two approaches to the analysis of lean automation: the first looks at how automation – in terms of the intelligent drives and controls now residing in many manufacuting lines, or the transaction management solutions on which so many service organisations now rely for efficiency – can be made leaner in itself through the use of lean principles in product design. The second approach identifies ways in which automation technologies can support the implementation of lean. The same double thinking can be applied to another “odd couple”, lean and IT.
From a lean perspective, automating can help an organisation tackle issues related to quality for example (also supporting principles such as standardised work, reliability and elimination of variation). Think about the machines LEGO uses to count the bricks going into each box (see page 38 to read our case study on LEGO). Automating without a strong business case or accurante forecasts, however, can be counter productive, involving significant capital expenditure, excess capacity, the potential loss of jobs and a disengaged workforce. There needs to be a clear understanding of what the need for automation is and of the flow of value around the proposed point of automation.
Similarly, automating a single process without considering the effect this will have on the movement of bottlenecks across your combined processes is likely to cause problems to leap up where there were none before. What may seem like an easy, quick fix to increase output will end up damaging the entire system.
It is also important to have an adequate maintenance regime. TPM procedures must be in place, otherwise automating would be like buying a car and not replacing the tyres when they are worn out. A dangerous game.
Investing in automation without having taken the necessary steps to reduce as much waste as possible first is a common mistake. Toyota, for example, identifies automation as the last step a company should take, after waste reduction and kaizen initiatives. First is low cost automation, and only later on, large scale automation. In other words, first comes lean, then comes automation.
For instance, applying cellular manufacturing to improve flow will dramatically reduce the need for complex automation, as will reducing batch size. Implementing lean and then using automation to strengthen the results achieved is the way to go, bearing in mind, however, that there is no secret recipe for success and that every company should find their own road to the best outcome for them.
In the following two case studies, Eaton and SCHAD share their opinions on lean automation and tell us about their solutions.
A key challenge facing industry today is the development of automation systems that offer data transparency and scalability while satisfying the constant demands for increased performance, additional functionality and cost reduction. The fast developing concept of lean automation is, however, providing innovative and effective ways of meeting this challenge, says Stuart Greenwood of Eaton’s Electrical Sector.
The concept of lean manufacturing is widely known, as are the benefits it offers in terms of enhanced efficiency, continuous improvements in product quality and the elimination of waste. But what is lean automation? In essence, it is the development of automation systems that mirror many of the benefits of lean manufacturing.
For example, lean automation makes the design and implementation of automation systems more efficient, it facilitates continuous improvements in the performance and capabilities of those systems, and it provides scalability that eliminates wasted design effort by allowing the same basic design of automation system to be used for a whole range of machines.
In fact, lean automation slims down control panels, simplifies wiring, increases data transparency, reduces engineering and commissioning requirements, increases performance and reduces costs, and it does all of these things to a degree that is not even approached by any other automation concept.
So much for the theory, but what are the practicalities of lean automation? To answer this question, it’s necessary first to look at the two core technologies that underpin it. The first is bus-based control wiring systems (or lean panel wiring systems) for use in control panels, of which Eaton’s SmartWire-DT system is an example. The second core technology is the integrated HMI/PLC.
Lean panel wiring systems revolutionise the design and construction of control panels. All of the conventional control wiring is eliminated, replaced by a single bus cable that loops round the devices within the panel, including, for example, motor starters, inverters, pushbuttons and indicator lights. This single cable links all of the devices direct to the PLC or smart relay that forms the basis of the control system, thereby virtually eliminating the need for this unit to have conventional inputs and outputs.
The inherent simplicity of lean panel wiring systems means that modifications and updates can be incorporated easily and inexpensively. This same simplicity also facilitates the design of scalable and modular systems that are applicable to a whole range of machines.
In addition, these systems not only carry control signals to and from automation devices, but also data. This means, in principle, that any control device, whether it’s something as simple as a sensor or as complex as a motion controller, can send data to the PLC for onward transmission to a high-level SCADA or ERP system, thereby providing complete data transparency.
Put simply, adopting lean panel wiring greatly improves the transparency of the automation system. Since fieldbus and network based field wiring already supports information exchange, the addition of lean panel wiring means, in essence, that any information about any aspect of the automation system’s operation and status can be made available wherever it is needed. This transparency is one of the key elements for lean automation, which is one of the reasons that the description lean panel wiring for the new busbased systems is preferred.
Let’s turn now to the second core technology for lean automation – the integrated HMI/PLC. These devices have essentially been made practical by lean wiring systems, which mean that they have to make only minimal provision for conventional I/O. This has allowed the HMI and PLC functions, which are in any case closely related, to be brought together in a single compact unit. Compared with the use of a separate HMI and PLC, cost and space savings are the immediate benefits, but another key factor is that programming is simplified.
The best of the HMI/PLC products also have comprehensive communication options enabling them to readily exchange data with external systems. This means that the automation system is no longer an isolated island of intelligence, but a fully integrated part of the production plant capable of communicating directly with the IT systems that handle, for example, customer order scheduling and quality control.
Now let’s look briefly at how the move toward lean technology has already affected the design of automation systems, and how it is likely to affect them in future.
Many of the automation systems in use today are based on what might be described as “traditional” architecture, with a central PLC, a separate HMI and conventional wiring both in the control panel and the field. This type of architecture is, however, very labour intensive in view of the large amount of wiring needed. It is also inflexible and difficult to modify, and it provides a relatively poor level of data transparency, as the control wiring is, in most cases, unable to transport data to the PLC.
The first step forward was to replace the conventional field wiring with a fieldbus system and to start using remote I/O modules. This greatly reduces the amount of wiring needed in the field, and also makes the system more flexible. However, it brings only marginal benefits within the control panel and, in particular, does nothing to make the control panel easier to modify. It does, to some extent, enhance data transparency, as most fieldbus systems can transport data. Data from devices mounted within the panel, such as starters and drives, usually remains inaccessible, however.
Today, we can take another step forward and produce automation systems with an integrated HMI/PLC and lean wiring within the control panel, complemented by remote I/O modules and a fieldbus system for field wiring (see figure 1). This architecture – which can be implemented with currently available products – gets close to delivering all of the central benefits of lean automation.
Less space is needed in the control panel than with the older architectures, and the amount of wiring is greatly reduced both inside and outside the panel, with a consequent reduction in costs. Flexibility is much enhanced and the PLC can readily access data from all of the key automation components. The greater flexibility and reduced costs of this approach also make other improvements – such as automating product changeovers on the machine that’s being controlled instead of relying on time-consuming manual resetting – practical and cost effective.
In the near future, it will be possible to go even further down the road to lean automation, by using a single busbased wiring system inside and outside the control panel, thereby eliminating the need for a separate fieldbus. (See figure 2). This will provide further cost reductions, exceptional flexibility and complete data transparency. In short, it will meet all of the requirements that have been identified as being essential for future automation systems.
James Hannay, senior VP of international operations at engineering mobility specialist SCHAD and an expert in mobile SCADA systems, shares his opinion on how automation can support a lean programme.
Levels of automation within manufacturing are increasing to help drive down costs and improve efficiency. This is central to the thinking behind lean, with its emphasis on achieving more with less through the continuous elimination of waste. Whilst it originated in manufacturing, the concept of lean is not restricted to this sector. When it comes to automation, it is possible to learn valuable lessons on how to maximise existing investments by looking at other industries, like e-commerce, large scale distribution and airport operations.
How can companies investing in automation think about lowering their total cost of ownership? And how could this contribute to achieving typical lean objectives such as increasing Overall Equipment Effectiveness (just to name one)?
Mobile SCADA is one technology that has made inroads across a broad range of industries to prove its value. Consider a fictional day in the life of an automation engineer responsible for monitoring traditional SCADA visualisations in a fixed control room to appreciate why.
A Programmable Logic Controller (PLC) on the shopfloor generates a timeout notification for a specific photo sensor. The control room engineer notes the photo sensor needs replacing and starts to call other engineers on the floor to allocate the task and fix the problem.
However, he does not know who is available and what they are currently working on. He has to assess the situation and decide whether to take someone off an existing task or wait until someone becomes available without all the available information to hand. His options are to re-prioritise based on the information he has, to wait until someone becomes available, or to leave the control room unmanned.
If the control room is left unmanned, a new notification is likely to arrive while the room is empty. With no engineers available, he decides to leave the control room, but after installing the new photo sensor, he receives no positive feedback that the fault has been effectively resolved until he returns to the control room to check the displays. Once back in the control room, he finally spots the next notification, which requires his attention in a completely different location and the decision making process re-starts. Off he goes again, leaving the control room empty and the SCADA alerts continue to arrive, unnoticed. Engineers face the challenges of working with constantly changing priorities, which contributes to more downtime, less efficiency, slower reaction times and less productivity.
Using mobile SCADA, alerts are still sent to the control room but are also directly issued to an appropriately qualified engineer. The faulty photo sensor notification is immediately sent to the smartphone or hand held terminal of a predefined group, including the engineer in the control room. All the recipients are qualified to fix that category of fault based on availability, location and skillset. This enables any engineer within the group to immediately take control of the notification, review the situation on the mobile device, make the necessary decisions quickly and fix the problem in a much shorter time. The control room engineer accepts the notification and the control room immediately becomes mobile.
Whilst carrying out the repair, he receives the second notification. Critically, though, after a few seconds he also sees an alert on his mobile device confirming another engineer nearby has accepted the notification and is fixing the problem, which means that resources are utilised for responding to incidents faster and more efficiently. After completing the repair, the engineer immediately checks his mobile to see whether it was successful, using the device to check the settings of the photo sensor, PLC and SCADA system while he is on the move.
The experience of Vanderlande, who is contracted to manage baggage-handling operations at Munich Airport, provides a real world example illustrating how mobile SCADA could contribute to lean management by ensuring high automation uptime.
Being a hub airport, timing within Munich’s logistics operation is tight and inflexible. Vanderlande operates three classes of automated conveyor lines capable of handling up to 800, 1,200 or 2,400 pieces of luggage per hour, which equates to a maximum rate of 40 pieces of luggage being sorted every minute.
These baggage handling systems are controlled by a large number of PLCs connected via Ethernet, which control around 140,000 notifications monitored by the SCADA system. Prior to using mobile SCADA, control room personnel would manually forward notifications to service staff working in the field.
Now, service engineers responsible for running and supporting the high-speed baggage handling systems receive notifications of malfunctions, on their mobile device within seconds of it happening. Engineers can respond much faster, review documents, review settings of the PLCs and the SCADA system and review routine maintenance information – all on the mobile device, which contributes to ensuring luggage reaches customers or connecting flights on time, thereby reducing the “left behind index”. As a result of the mobile SCADA system, which uses the airport’s existing Wi-Fi and GPRS connectivity, Vanderlande has exceeded its entire service level agreements with Munich Airport.
The mobile SCADA system is directly connected to the existing PLCs, handling notifications and instantly dispatching them to the mobile devices used by maintenance staff. The system has also been connected to the existing maintenance software system, allowing service engineers to complete work orders, access information about spare parts stock availability, and review documents such as wiring diagrams on the same mobile devices through a single user interface.
As an outsourced service provider, Vanderlande’s adherence to certain KPIs is monitored continuously. Each day around 200 short term failures occur within in the baggage handling area of Munich Airport’s Terminal 1. After implementing mobile SCADA, the response time to each failure and corresponding system downtime was reduced significantly. By optimising the use of resources through reduced repair time, quicker notification and escalation, access to information and connectivity to the maintenance system means higher availability of service personnel to carry out both planned and unplanned repair and maintenance tasks. As the outsourced service provider, Vanderlande is able to optimise resourcing levels and significantly reduce total cost of ownership.
The contribution made by mobile SCADA to achieving typical lean objectives is significant, through reducing unplanned downtime and greater resource utilisation effectiveness. When mobile SCADA is combined with the incumbent maintenance system, where the central maintenance system can also be accessed using the same mobile device in response to a SCADA alert, the benefits are significant. By giving engineers the ability to review historical information relating to equipment downtime and routine maintenance whilst responding to a SCADA event, the return on investment of a mobile SCADA system is significant in any organisation looking to improve operational efficiency, whilst at the same time helping to drive down costs.
For more information visit www.schad-automation.com.