Introduction to maintenance strategy
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This document provides an introduction to maintenance. It discusses different types of maintenance including preventive, corrective, planned and unplanned maintenance. It also discusses typical work distributions for maintenance in engineering and critical industries. Preventive maintenance makes up the majority at 50-70% while breakdowns are a smaller percentage. The document also contains an example problem calculating the number of repair crews needed based on machine breakdown rates and crew repair rates.
Introduction to maintenance strategy
- 1. Introduction to Maintenance Dr. Munthear Alqaderi munthear@gmail.com
- 3. Maintenance Preventive M. “To Keep” Corrective M. “To Restore” A facility to an acceptable standard What is Maintenance?
- 4. Maintenance Works Planned ≥ 70 % Unplanned ≤ 30 % Minor repairs ≤ 20 % Breakdown ≤10 % PM ≥ 50 % overhaul ≥ 20 % Typical Work (man-hour) distribution in engineering industries
- 5. Minor repairs ≤ 10 % Breakdown ≤ 5 % PM ≥ 70 % Overhaul ≥ 15 % Maintenance Works Planned ≥ 85 % Unplanned ≤ 15 % Typical work effort (man-hour) distribution in critical industries (such as gas, oil, steam , power equipment)
- 6. Maintenance Costs Maintenance Commitment Cost PM Cost Total Maintenance Cost Breakdown Cost Optimal
- 7. Determining the Size of Repair Crews Problem: A factory has 200 machines and the maintenance engineer supervises the repair crews who repair malfunctioning machines. The maintenance policy is to repair the broken down machine and bring back in production within 2 hours on the average. If average breakdown rate is 3.5 machines/hour and each repair crew can repair 0.25 machine per hour on the average. How many repair crews are required ?
- 8. Solution The formula for average repair rate () is 1 ts = ---------- or = + 1/ ts - Where = repair rate = arrival rate of malfunctioning machines ts = average time arrivals in the system Required average repair rate = 3.5 + 1 / 2 = 4 machines / hour No. of Crews = machines/hour a crew can repair = 4 0.25 = 16 repair crews required
- 9. Types of Maintenance MAINTENANCE UNPLANNED MAINTENANCE (REACTIVE) BREAKDOWN EMERGENCY PLANNED MAINTENANCE (PROACTIVE) CORRECTIVE MAINTENANCE REMEDIAL DEFERRED PREDECTIVE MAINTENANCE CONDITION - BASED STATISTICAL - BASED PREVENTIVE MAINTENANCE ROUTINE RUNNING DESIGN - OUT ENGINEERING SERVICES WINDOW IMPROVEMENT MAINTENANCE SHUTDOWN CORRECTIVE SHUTDOWN PREVENTIVE SHUTDOWN IMPROVEMENT Shutdown Maintenance OPPORTU- NITY
- 14. Maintenance Strategy Implementation Breakdown Preventive Predictive 1 2 3 4 5 6 7 8 9 10 Year 100% 80% 60% 40% 20% 0% Percentage of Maintenance Time by Strategy