If left on their own, material handling assets will slowly degrade and eventually fail, often at the most inopportune moment. But with a little planning, you can not only extend their useful life, you can also optimize performance.
Automation assets typically evolve through four distinct stages: design, execution, support and optimization. In too many instances, however, the optimization phase is haphazard or ignored totally. Performance reaches a peak and then begins to tail off. This process happens for many reasons: the people who implemented the systems may have moved on and their successors do not feel vested in the system; there may be no mechanisms in place to monitor performance; or business may be so good that there is little incentive to seek improvement.
Whatever the reason for not optimizing, today’s global economy requires warehouses and distribution centers to extract maximum value from their automation investments. This should start with a close audit of both the risks of doing nothing and the full potential of extending the useful life of automation assets.
Evaluating the Risk
An audit begins with an analysis of current assets with an eye to extending their useful life. Create a profile of each key asset in your facility, including software, controls, peripheral electrical devices and mechanical equipment. If you don’t have an inventory, vendors of each asset should be able to provide it. From here you can create a master inventory, categorizing the potential obsolescence of each piece and its strategic importance and then creating a plan to mitigate those risks. Each layer should be categorized per its strategic importance to your business, as follows:
Critical Risk: Assets that can affect your entire system. These would require a recovery plan for mitigating problems in the short run and in the longer term a budgeting strategy to cover total replacement, if needed, with the replacement costs phased across several budget cycles.
High Risk: Components that might lead to partial system failure. These can also result in extended downtime and would also require a recovery plan and some longer-term budget planning, perhaps balancing cost between capital and MRO expenses.
Medium or Low Risk: This usually involves components where failure would not lead to partial or total system failure. Downtime is minimal and replacement costs can usually be handled out of MRO budgets. A good spares strategy aimed at having adequate replacement components on hand can keep risk in check.
With an understanding of your risk and good planning, you can substantially extend the life of your system, minimize unanticipated downtime and operate mechanical, control, software and electrical devices to their fullest potential.
Extending Mechanical System Life
The use of conveyors, sorters, automated storage and retrieval systems, and other capital equipment most likely represents the greatest risk and highest capital expense in a warehouse or distribution facility. All systems are subject to wear and performance degradation over time. Effective run time may be reduced, or other problems—such as friction from a worn component contributing noise that pushes the system beyond OSHA acceptable levels—may demand attention. The more you can do to extend the useful working life of your systems, the greater the impact on profitability.
While total replacement is usually a major capital expense, system life can often be extended by making improvements at the component level. A shoe sorter near the end of its life, for example, can often be rebuilt. Replacement of a worn component might keep the sorter running well and maintain uptime. Or, if there is a noise issue, a newer product designed for quieter operation might be the solution. And if component rebuild or replacement is an option, it can often be done over the weekend in advance of peak season.
Another valuable way to manage the lifecycle of your mechanical equipment is a spares strategy that corresponds to the criticality and projected lifecycle of key components. While one may have been developed when the system was purchased, spares strategies should be revisited regularly as the system ages.
Managing Electrical Devices
Optimal warehouse operation also depends on the reliability of numerous electrical devices, such as scanners, I/O modules, actuators and servo motors. These have variable degrees of risk so it is important to analyze the risk of operating each device as it ages. While some vendors do designate the expected life of each device, others do not, leaving you to make your best guess.
Effective risk analysis can provide companies with options. For example, in a risk analysis made on servo drives, automation planners identified eight Baldor servos as heading toward obsolescence, based on their age. A failure in any one of these could have led to weeks of downtime before a replacement were found. Facing possibly $80,000 in replacement expenses, the company was provided with options other than total immediate replacement.
If some spares were available, the company could buy them and phase in replacement. It might, for example, replace the four oldest servos immediately and save what they had removed for use as back-ups. This would extend operating life while providing more flexibility to spread the costs between capex and MRO.
Most material handling systems depend on PLC control. Because their operation is simple, PLCs tend to last and most PLC vendors announce expected end of life well in advance. Rockwell/Allen Bradley, for example, no longer supports the TI 45 PLC, but, as announced, will continue to support its latest ControlLogix PLC.
The closer your PLC is to the end of its life, the greater the possibility of failure and, if it does go down, there will be downtime. Depending on what is at risk, upgrading to a more modern PLC not only assures operation, it may also be a way to tap deeper into the value of other assets.
In addition to being more robust and reliable, newer PLCs may have enough bandwidth to support analytical tools that can help identify trends, which can extend the life of the systems they control. Additionally, having Ethernet capability can help drive integration of the warehouse control system (WCS) with other automation systems.
Some smaller operations use PCs to control their plants. PCs can become obsolete in less than two years and it is usually more economical to replace than upgrade them.
Managing Warehouse Control Software
Obsolescence of the software platform supporting the WCS is an unavoidable reality. When the WCS goes down, the warehouse is down for what could be many days—or even weeks—of configuration and testing.
Many WCSs are still running on Windows 2003, which Microsoft no longer supports. Your system will continue to operate on Windows 2003, but you will be on your own if technical problems arise and it may be risky to connect legacy or third-party applications to your WCS. If you are running Windows 2007 and 2008, you will be in the same situation in 2020, when Microsoft pulls the plug on those systems. The good news is that Microsoft, like most software companies, gives notice on how long they will support their products.
But this may provide an opportunity as well. Upgrading to the latest supported software version could be an affordable expense that maximizes performance and reduces the risk of maintaining other assets. With the later version, for example, thin client solutions become possible, enabling consolidation of IT architecture in a virtual rather than a physical server. For an investment of $250,000 in virtualized controls, you would not only have an operating system that would be supported for years, you would also gain advantages in software maintenance, disaster recovery and other areas, not the least of which is eliminating the need for physical servers.
Although we have focused on the often-neglected optimization phase of the automation lifecycle, all operational phases are critical to continuous improvement. Attention to extending the lifecycle at the design phase might manifest itself in a design with open technologies or reusable engineering objects, so that the systems can incorporate best of breed solutions without having to abandon the entire investment.
At the execution phase, asset management may be enhanced by warehouse execution systems, which coordinate operations so that human resources and equipment are efficiently operated and used. And it is the support phase where spares management, condition monitoring, preventive maintenance and other strategies are implemented to sustain any optimization measures that need to be taken.
Wynright Corp. (Elk Grove, IL), a wholly owned subsidiary of Daifuku North America, is a provider of intelligent material handling systems.