Improving equipment reliability can be approached in two ways; pro-active or re-active.
Pro-active entails the development of maintenance strategies and tactics commencing with OEM directives and improved through the application of the RCM methodology.
Re-active identifies the root causes (RCA) using actual equipment response data (failures, faults and defects) followed by a defect elimination program.
The first approach is arguably the best but could be tedious and could lack during the execution phase. The second is a more practical approach that looks at both maintenance content and execution.
Equipment reliability depends largely on the interaction between man and machine, i.e. the way the equipment is designed, installed, commissioned, operated and maintained. If treated well the equipment will equally respond with high reliability and OEE values. The people thus are in control through proper application and management of the processes and procedures, performed by well trained personnel following well developed procedures.
On the contrary, if mistreated, the equipment will respond in like manner by refusing to co-operate (stoppages) with resultant poor reliability and OEE values. In this instance the equipment is in control through the stoppages and breakdowns.
RELIABILITY IMPROVEMENT ROADMAP
Key to the reliability improvement program is recording (digitising) the human interaction and machine response. Recording the human interaction with equipment is complex as this entails monitoring task execution by operations and maintenance personnel. On the other hand, the three 'Machine Response' parameters are usually readily available in the plant although in different systems and in different formats. The drive is thus to digitise these processes using Industry 4.0 technologies and to make the results available in a data portal.
Man - Machine Interaction
Presenting a maintenance work order in paper format will most probably result in the work being done in the field (based on personal expertise and experience) with feedback given once the job is completed. Availing the tasks in digital format on a smartwatch will result in steps/procedures being followed diligently with feedback completed in real time in the field.
OEE (Plant Downtime) Reasons
Stoppage times and reasons (failure codes) for the relevant production equipment are vital to identify problem areas and to address these for OEE improvement. Using Industry 4.0 technology provides online OEE values from either existing systems or from easy to install IoT devices that can be up and running within half a day.
Condition Monitoring - Faults
Regular monitoring of plant equipment utilising available CM technologies provides valuable information on the condition of the equipment with the identified CM faults that need to be corrected. Extracting this fault information from the condition monitoring reports into a central database linked to a portal provides insight into recurring faults detected with the CM technologies.
Daily plant inspections by the people closest to the equipment are extremely important as they best know the equipment and can quickly report on changes in equipment behaviour such as abnormal noise, vibration and temperature. Digital inspections using mobile devices and cloud services make findings immediately available to the relevant managers.
ROOT CAUSE ANALYSIS
At the heart of the reliability improvement initiative is root cause analysis. Identifying the real cause for recurring problems provides the best possible way to permanently eliminate these. Applying cause mapping using Excel RCA templates ensure that solutions to the root causes are identified, implemented and progress easily monitored.
Winston Ledet identified the value of defect elimination when working for du Pont during the early 2000's. Focussing on improvement in maintenance workflow (planning & scheduling) presented a 5% improvement in plant up-time whereas adding defect elimination presented a 19% (combined) improvement. A well structured defect elimination program can present such results.