Too many Preventive (PM) Maintenance programs contain ambiguous and needless tasks at unnecessary frequencies. What makes this so shocking is that plant facilities send out their craftspeople to work thousands and thousands of hours each year, performing what should be the plant's most important work, armed with ineffective and inefficient PM tasks and standards.
The first step to optimizing your program is determining where to get started. In most plants, there are several sources of information where the problems exist including equipment delay information, high repair cost list, quality issue reports, and failure reports including Mean Time Between Failure (MTBF) statistics. If the plant's trouble spots also have weak PMs that do not address the known failure modes, than you've found the place to get started.
The next step is to form a team to work on the PM improvement process. At a minimum, the team should be made up of a craftsperson from each of the trades involved plus an operator or operating supervisor and a maintenance supervisor, planner, and reliability engineer. The choice of craftspeople is most important. He or she should be very knowledgeable and preferably the person currently performing the PMs in the area.
Guidelines for Improving a PM / PdM Program
1. Make a list of the assets that you plan to analyze. Verify that the list is complete using drawings and/or field verifications. 2. Break each asset down to major systems/major components. 3. Utilize any appropriate information such as OEM (vendor) manuals, drawings, training manuals, bills of material and prior PMs. 4. Analyze each major system/component separately by using the form shown in Figure 1.0.
1. For each component, list any actual or likely future functional failures that may occur. 2. For each functional failure, develop one or more PM or PdM task(s) that are appropriate. These tasks must either prevent or mitigate the consequences of the failure. 3. For tasks that do not address known failure modes, consider removing them. 4. For each PM task, provide adequate detail by asking multiple - and varied - questions relating to task location, performance and frequency. 5. Finally, test the PM tasks the team has developed by having someone not involved in the development perform it. This validation is especially important when the team first starts developing new PMs.
Documenting the New PM In order to track the PM improvement process, all changes should be properly documented and approved before changes are made in the Computerized Maintenance Management System (CMMS). A form for documenting these changes is shown in Figure 2.0.
Conclusion Optimizing a plant's PM program has many benefits including improving equipment reliability, improving production and craft productivity, and in reducing maintenance costs. In addition, craft morale improves when the craftspeople feel that they are doing the right things and have key input into their plant's reliability improvement process.