Lean maintenance is the application of lean philosophies, methods, tools and techniques to reliability functions. It has the same fundamental goals: eliminating waste associated with labour, inventory, procedures and techniques. This results in improved productivity and reduced costs.
Lean maintenance doesn’t imply a slash-and-dash approach in eliminating jobs and cutting costs. This common strategy doesn’t eliminate waste or cut costs. A lean maintenance philosophy reduces costs by eliminating waste that can be defined as "anything that doesn’t add value to the product, process or service."
There are many tools used to implement lean principles in manufacturing that also apply to maintenance. They include: 5S, Kaizen, just in time (JIT), elimination of the seven deadly wastes and the like. In this article, we’ll specifically analyze how the use of a computerized maintenance management software (CMMS) system can be a tool and help you accomplish lean goals.
Waste in maintenance
Overproduction: In the maintenance environment, overproduction is doing any work that doesn’t add value. Performing preventive maintenance (PM) and predictive maintenance (PdM) tasks more often than is necessary and re-doing jobs, which were not done correctly the first time, are examples.
Waiting: Areas of waste in this category include maintenance personnel waiting for equipment availability, job assignments, tools, parts, instructions other crafts and permit approval, etc. Waiting isn’t a value-added activity and should be eliminated or reduced as much as possible.
Transportation: Unnecessary travel is the result of ineffective planning and scheduling. Examples include travelling to the maintenance shop to get technical information (i.e. O/M manual and prints) and travelling to the storeroom for parts and tools. Poorly designed PM routes are also a major contributor, yet not visible.
Process waste: When performing a breakdown repair, maintenance personnel are typically under lot of pressure to fix the machine as soon as possible and return it to production. Maintainers, however, aren’t given enough time to fix the repair appropriately. This results in a poor repair and recurring problems. Properly performed repairs would eliminate this process waste and save lost production time in the long term.
These days, most organizations use some sort of CMMS system or enterprise asset management (EAM) system. Processing waste also occur when inefficiencies exist in these systems. Examples include a poorly designed system that requires multiple entries of the same data, or a material requisitioning process that requires redundant approvals.
Defects: In maintenance, a defect can be defined as leaving an asset in an unreliable condition. There are many causes of defects in the maintenance environment. Defects due to poor workmanship arise from inadequate training, inadequate/outdated procedures and not having proper tools to do the job.
Equipment/asset reliability can minimize defects. Machines that are reliable produce less scrap and product that’s within specification, which eliminates the cause of defect correction. Equipment must be ready to run when demand is presented.
Parts inventory: Examples of waste with spare-parts inventory management include:
• Obsolete inventory: Most storerooms contain a significant amount of obsolete inventory. Obsolete inventory ties up capital and consumes management resources. It can easily amount to 10- to 20 percent of annual inventory dollars;
• Excessive inventory isn’t obsolete, but it’s inventory maintained at unnecessarily high levels. Excessive inventory also ties up capital and consumes management resources; and
• Inadequate PM programs cause equipment failures, which in turn, results in additional parts requirement (consuming working capital) and downtime.
A CMMS/EAM system can monitor and control parts inventory. It keeps track of inventory items, vendor performance, parts receipts, issues and returns. In addition, CMMS/EAM systems can automate the parts purchasing process. Vendor-managed and stocked inventory can also drastically reduce parts quantity (stocked in the storeroom) and save money.
Root cause: Breakdowns and failures are never planned and cause the loss of production and money. Finding the root cause of a failure provides an organization with a solvable problem. Once the root cause is identified, a fix can be developed and implemented that prevents a recurring failure situation.
Work flow: One of the common performance metrics is planned versus unplanned work orders. The benchmark goal has been 90-percent planned (PM and other planned activities) and 10-percent unplanned corrective/breakdown maintenance. In reality, with most organizations, the ratio is anywhere from 10- to 30-percent planned maintenance to 90- to 70-percent unplanned. This is indicative of operating in a reactive mode, which contributes to waste, reduced equipment life and lost productivity.
A thorough understanding and analysis of a maintenance work-process flow makes it easier to identify and eliminate waste. The goal is not only to eliminate waste, but also to develop an improved work process flow that’s more effective and productive. As the flow is thoroughly reviewed and analyzed, the entire process flow becomes visible and wasteful activities, such as delays, unnecessary travel and the like, are easily identified.
Trending: Condition monitoring usually involves the use of installed devices (i.e. gauges and meters) to monitor the operating conditions of equipment and other assets. An example is a pressure gauge on a chiller. Maintenance can establish operating limits for the condition(s) being monitored and trend the observed data. If the observed data is outside of certain predefined range of values, some maintenance action may be required. This is referred to as condition-based maintenance and can be very effective and less expensive than periodic or fixed-frequency maintenance.
Planning and scheduling: The planner/scheduler role is very important in a lean maintenance environment. The goal is to optimize utilization of available resources. Detailed job plans should be developed for all approved open work orders, including:
• Number of and type of labour resources (how many plumbers, carpenters, etc.);
• Time estimates, so required manpower can be determined;
• Detail job steps, including permit/safety requirements;
• Parts and tools requirements (pre-kit if necessary);
• Clear job instructions, drawings, sketches, etc.;
• Job-site walk down to determine the most efficient way of performing work;
• Equipment availability coordination; and
• Outside contractor requirements (if any).
Delays must be avoided at all cost. Weekly scheduling must be done with daily fine-tuning as necessary. This level of detail and coordination is required to achieve a lean and efficient maintenance operation.
How can CMMS/EAM systems help?
CMMS/EAM systems can be looked upon as a tool, which can help implement and support lean maintenance in many different ways:
• The CMMS/EAM system enables the use of lean principles by refining PM activities. For example, it allows users to define assets in terms of size, type, subtype and location, as well as customize the PM to a specific asset. This way, you can control and optimize PM frequencies for specific types of equipment. A CMMS/EAM system’s ability to track and manage work requests, labour, planning and scheduling allows companies to stream line the work process flow. This cuts waste and improves productivity.
• With easy access to detailed asset information, maintenance planners are better equipped to schedule tasks, plan routes and estimate materials required. For example, multiple assets that share similar requirements or are at the same location may be combined in a single work order, cutting maintenance labour costs.
• CMMS/EAM systems can produce reports that indicate overdue PM tasks. Performing PMs on time can contribute to higher equipment uptime, resulting in higher overall productivity.
• A critical aspect of maintenance planning is the availability of "real-time" data. The CMMS/EAM system utilizes the real-time information via mobile technology to allow usage-based scheduling of maintenance tasks as opposed to fixed-calendar based. For example, an air-handler PM might be scheduled on runtime hours instead of at monthly intervals.
• Real-time information allows users to set alarms that are based on condition monitoring. For example, if a temperature reading is outside of a predefined range, the CMMS/EAM system can automatically issue a work order.
Done right, lean concepts can lower maintenance cost and increase productivity.
Kris Bagadia, is president of Brookfield, WI-based PEAK Industrial Solutions. You can reach him by email at: firstname.lastname@example.org.