It was companies like Toyota who originally defined lean and just-in-time manufacturing philosophies, where components and body panels would turn up on the line precisely when needed. Although this is an extremely efficient way of doing things – in terms of time, stock holding and real estate – it does place an enormous burden on downstream processes, as the just in time (JIT) chain is only as strong as its weakest link. JIT, coupled to 24/7 manufacturing, also presents maintenance departments with a real challenge. The only significant downtime available to them is during the two week summer shutdown; so all major engineering projects have to be completed in a very small window prior to full manufacturing starting up again. At Toyota's vehicle plant in Burnaston, Derbyshire, one major engineering project – the refurbishment of AGVs that serviced the presses at the beginning of the production line – was identified as one that could have serious implications in case of a breakdown.
Originally classified as a refurbishment, a sudden change in manufacturing priorities due to the new Auris and Avensis models immediately elevated it to a critical level...but with a reasonably short window of opportunity. However, thanks to lateral thinking by Rockwell Automation Solution Partner AND Automation, coupled to Toyota's willingness to entertain alternative technologies, the problem was solved quickly and with a Rockwell Automation based solution that offers a far simpler and more effective upgrade path.
The AGVs travelled back and forth between four different locations, two sides of the press, the stacker and the de-stacker. Stuart Cope, Press Engineer, Press and Weld Division, at Toyota explains: “The AGV system originally comprised eight vehicles and was subject to a number of upgrades over the years, with units and control systems being removed and updated. Last year we were left with just one remaining serviceable vehicle, but the infrastructure was for eight and was complex and hard to look after; it was becoming a liability. “As the press was not running all the time it was originally decided that another refurbishment would suffice,” Cope continues. “However, an upturn in sales meant that the press would be in far greater demand and indeed a second press would come into operation.
The refurbishment was replaced by the need for a completely new system... one that had to be developed quickly and then installed within the summer shut down.” Toyota had to find someone who could provide the new system within the original budget and subsequently contacted multiple AGV/RGV manufacturers along with numerous automation and control specialists. One such specialist was AND Automation, who Toyota had used before. AND Automation came up with the suggestion for a rail-guided system, which not only offered robustness and simplicity but, just as importantly, could be designed and installed on budget and within the restricted time frame. “AND Automation showed us the company that would be providing the hardware,” Cope explains. “We were impressed with the robustness. Everything in a press shop has to be robust as it all gets an absolute hammering.”
Tony Brooks, Sales Director at AND Automation, explains the solution his company developed: “The existing control infrastructure was driven by an Allen-Bradley® PLC5®, which meant that integration of a new contemporary solution from Rockwell Automation would be far simpler. Toyota was also happy with its Allen-Bradley® equipment and therefore the learning curve was shallower.”
The new control solution deployed to drive the rail guided trolley cars has an Allen-Bradley CompactGuardLogix® programmable automation controller (PAC) at its heart. Communications to all primary devices and to various I/O points, including safety and non-safety Point I/O™, are via EtherNet/IP. Each trolley car has remote controls, I/O, safety I/O and on-board intelligence to look at and react to dumb targets on walls and machines.
The main panel, which houses the PAC, power distribution and I/O, feeds remote panels which house Allen-Bradley PowerFlex® drives (for positional control), safety I/O and I/O for all three cars. A PowerFlex 753 is used for accurate position control of the main drive, while a PowerFlex 4 is used for the roller bed conveyors on the trolley cars. The drives, which run over EtherNet/IP, also deploy safe torque-off boards. Completing the primary components is an Allen-Bradley PanelView™ HMI on the door of main panel to provide full diagnostics, set up, configuration and alarms. The safety solution comprises a fence line with multiple entry points. These entry points interface with the safety solutions on other machines and can create multiple, changing zones depending on where the operator enters. The GuardLogix PAC allows Toyota to deploy functional safety, which is programmed rather than hard wired. As a result, clever monitoring of the trolley positions creates multiple dynamic safety zones, giving the customer greater flexibility.
“We don't have any other rail-guided solutions apart from this one, so to us it was new. It is doing a superb job. We have had a few minor teething issues mainly down to the older comms method, but AND Automation has been able to mimic the old comms system but on much more up-to-date hardware. The up time is very, very good... far better than the old system.” Jenny Brosnan, Section Manager, Purchasing Department at Toyota, discusses the project from a purchasing perspective: “Typically as a business, when we are looking to purchase equipment we work with the production department to develop a specification and then go out to market. This project started this way – we knew we wanted to upgrade or replace. The great thing is that we have the flexibility to accept alternative suggestions; we are open to other ideas. “When AND Automation came back to us,” Brosnan continues, “rather than adhering tightly to the specification we quickly realized that there might be a different technology that could achieve the same result.
To us it was refreshing – challenging a tried and tested method. We had no comparison, but commercially it made sense and we wanted the press shop to buy in to the idea. “We continue to enjoy an open-book relationship with AND Automation,” she concludes, “they openly discuss with us how they reached the solution and a meeting with their suppliers eventually led to the creation of a project team. As the project started we needed to refine the new spec – driven by AND Automation, who took purchasing along with them, rather than just being at the start and end.
We were there all the way through – we could mould decision making process. From a procurement point of view, you often hear of companies who say “here is an exercise, here is the spec...” and “This company has not met the spec therefore they're out.” We, on the other hand, are happy to entertain alternatives.”
The results mentioned above are specific to Toyota's use of Rockwell Automation products and services in conjunction with other products. Specific results may vary for other customers.