Principles of Industrial Maintenance PDF

Course materials provided for personal study only and subject to the disclaimer on the ECU website http://www.ecu.edu.au/supplemental/disclaimer Principles of Industrial Maintenance Lecturer: D...

Course materials provided for personal study only and subject to the disclaimer on the ECU website http://www.ecu.edu.au/supplemental/disclaimer Principles of Industrial Maintenance Lecturer: Dr Ana Vafadar [email protected]  This lecture ⚫Coverage in this lecture will be largely derived from … Stephens, M. P. (2010) Productivity and reliability-based maintenance management. New Jersey: Pearson Education, Inc. (ISBN 9781557535924). Content from other sources will be indicated where applicable.  This lecture – the plan ⚫This lecture material is largely based on … Introduction (CHP 1) (Stephens, 2010) 1.1 Introduction to Maintenance Management 1.1.1 Definition of Maintenance 1.2 Maintenance Objectives 1.2.1 Primary Goals 1.2.2 Secondary Goals 1.3 Management and Structure of the Maintenance Function 1.3.1 Planning 1.3.2 Scheduling 1.5 Types of Maintenance Activities 1.5.1 Reactive of Corrective Maintenance 1.5.2 Preventive Maintenance (PM) 1.5.3 Predictive Maintenance (PDM)  This lecture in a nutshell ⚫This lecture will basically … Present the view that considers maintenance as a productive (profit making) rather than a cost function Identify the interplay between cost of breakdown maintenance and the level of proactive maintenance Identify the two activities of managing maintenance Present the three main approaches to maintenance  Fundamental Approaches to Maintenance Slide 5 ⚫An Introduction to Maintenance If you were asked … What methods could be used to improve productivity? A typical answer may be to … acquire more automated plant infrastructure that can … operate autonomously thereby reducing the worker/machine ratio have the capacity to produce more complex parts Hand in hand with this technology upgrade would be the need to have … effective planning and management of maintenance activities. This can be achieved with … more highly skilled maintenance crews to be recruited more elaborate (complicated) planning and management of maintenance operations the potential need to retrain staff away from just maintaining the old ‘conventional’ infrastructure  Fundamental Approaches to Maintenance Slide 6 ⚫An Introduction to Maintenance The concept being put forward here is that the maintenance function should be thought of as a profit producing entity of a plant or operation rather than an expense. Why … Effective maintenance strategies can help achieve … more production (through reduced machine downtime) minimal occurrence of idle equipment and under utilized personnel (through better machine availability) avoid missing production schedules and penalties for delays in delivery (through better machine condition) increased operator moral and output (through team participation) improved customer confidence and loyalty (through honouring commitments) In Summary … income expenses Profits ✓ gained - incurred =  Slide 7 Growing Expectation of Maintenance ❑ The First Generation : Period up to World War II ❑ The Second Generation: During World War II ❑ The Third Generation : Mid-Seventies Third Generation Higher Plant Availability Greater Safety Second Generation Better product quality Higher plant availability No Damage to the environment Longer equipment life Longer equipment life First Generation Lower cost Greater cost effectiveness Fix it when it broke RCM2 by John Moubray 1940 1950 1960 1970 1980 2000 7  Fundamental Approaches to Maintenance Slide 8 ⚫Defining Maintenance From the general to the more specific expressions… Maintenance: “the process of maintaining or preserving someone or something or the state of being maintained” (Oxford Dictionary, 1998, pg 1115) Maintenance: “all activities necessary to keep a system and all of its components in working order” (Stephens, 2004, pg 3) Maintenance: “the orderly control of activities required to keep a facility in an as-built condition, with the ability to maintain its original productive capacity” (Bagadia, 2006, pg 1) Bagadia, K. (2006). Computerized maintenance management Pearsall, J (ed.) (1998). The new Oxford dictionary of English. systems made easy. New York: McGraw-Hill Companies, Inc. Oxford: Oxford University Press  Fundamental Approaches to Maintenance Slide 9 ⚫Defining Maintenance The cost components of maintenance can be … Labour and material costs Lost production capacity (when maintenance is absent or ineffective) through failure What exactly do we mean by failure? Failure: “Any deviation or change in a product or a system from its satisfactory working condition to a condition that is below the acceptable or set operating standards for the system” (Stephens, 2004, pg 3) An effective maintenance programme will aim to eliminate or minimise failures Automation and increases in system complexity also means the need for maintenance techniques to move into some ‘advanced’ methods. For example Real-time/online monitoring  Fundamental Approaches to Maintenance Slide 10 ⚫Defining Maintenance The consequences of system or piece of equipment failing can give valuable insights into what type and level of maintenance activities should be applied. A typical relationship between the level of maintenance, repairs and costs is … total cost **The term proactive is being optimal level used here to include both preventive and/or predictive proactive maintenance. maintenance cost cost breakdown maintenance maintenance cost level Adapted from Fig 1-1: Stephens (2004)  Fundamental Approaches to Maintenance Slide 11 ⚫Defining Maintenance Consequences of different levels of maintenance (from the figure) Substantial costs can arise if proactive maintenance programs are implemented. In line this instance, the entire suite of possibilities may extend to: systematic (planned) shut-downs (for maintenance to be applied) regular equipment and system inspections (to check for faults) analyses: mechanical (via vibrations), chemical (on lubricants) and statistical (on failure data) precautionary (premature) parts replacement (even if operating) Too low a commitment to maintenance can lead to excessive costs. These are line associated with repair work done as a consequence of failure At some level between the two approaches to maintenance, an ‘optimal’ level of line maintenance level exists At the optimal level, the costs associated with (proactive maintenance) + the costs line associated with (repair maintenance) will be minimal  Fundamental Approaches to Maintenance Slide 12 ⚫Objectives of Maintenance The objectives of maintenance may be divided into Primary and Secondary goals. Primary objectives of maintenance include: Maintenance of existing plant equipment Inspection, cleaning and lubricating existing plant equipment Installation and modifications to existing plant equipment Maintenance of buildings and grounds (e.g., replacing water feed pipework to avoid debris in heat exchangers) Modifications to buildings Secondary objectives of maintenance include: Salvaging of obsolete plant equipment Disposal of spent/used consumables Environmental control (e.g., emissions monitoring to comply with regulations) Compliance with regulations or legislation: Occupational Safety and Health (OSH) and Environmental Protection Acts/Agency (EPA) requirements (e.g., the administrative work related to ensure compliance of maintenance operations)  Fundamental Approaches to Maintenance Slide 13 ⚫The Maintenance Function A number of factors affect how the maintenance function is managed and organised. In general, we can say there are three main factors here.... (1) Type of processes handled by plant will affect what methods/personnel are needed: Manufacturing processes Chemical and processes industries Food processing facilities (2) Level of system complexity will affect … Technical skills required (3) Plant size will affect … Number of maintenance personnel Physical resources that need to be provided Managing the Maintenance Function, requires … Maintenance Planning Maintenance Scheduling Both are aided by applying Computerized Maintenance Management Systems (CMMS)  Fundamental Approaches to Maintenance Slide 14 ⚫Maintenance Planning The maintenance planning function entails: Identifying and setting maintenance goals/objectives Establish the methods or procedures for achieving the set goals Achieving these two main activities, the maintenance planning function will have to: Prioritise work Create time estimates of the work needed Identify equipment and tooling needs for the tasks Specify the human resources necessary (team size, skill levels, training) Oversee the implementation of routine maintenance tasks by operators Examples: Machine cleaning, ongoing inspection, daily lubrication Identify what maintenance work will be done in-house or out-sourced Determine basic quality assurance measures for its operations Benchmarking by identifying acceptable deviations levels from set goals Identify causes of deviation Devise corrective actions  Fundamental Approaches to Maintenance Slide 15 ⚫Maintenance Scheduling Once a range of maintenance activities are ‘planned’, they need to be implemented. The maintenance scheduling function is responsible for the timely and systematic execution of planned activities (only those with all resources available). Maintenance scheduling will need to take into account … Job priorities set by maintenance planning (from planning) Time estimates for each task (from planning) Maintenance resource availability (crew, tooling, equipment) Establish appropriate time for implementation to reduce downtime (coincide with regular shut-downs) Maintenance scheduling activities may include: Planned (preventive, predictive) maintenance activities Unplanned (breakdown, corrective, repair) maintenance activities With the scheduling (sequencing, synchronization) of different (maintenance) work orders comes the inevitable queuing, or backlog of maintenance tasks  Fundamental Approaches to Maintenance Slide 16 ⚫Maintenance Scheduling Backlog levels Larger scheduling backlog results from having smaller pools of maintenance resources available. In this instance, the maintenance system is less responsive but probably always busy (well utilised). Higher likelihood of machine downtime. Smaller scheduling backlog results from having larger pools of maintenance resources available. In this instance, the maintenance system is quite responsive but sometimes idle (when not in need). Lower likelihood of machine downtime.  Fundamental Approaches to Maintenance ⚫Maintenance Scheduling Backlog Levels (sometimes referred to as ‘forward workload’) An estimate for the size of an expected backlog is given by Wiremann (2008, pg 39) Time element Hours EXAMPLE Work hours (regular, weekly) per crew (=10persons x 40hrs) 400 capacity Weekly Work hours (overtime, weekly) per crew (=10persons x 4 hrs) 40 Given *A total of Work hours (external contract staff, weekly) (=2persons x 40 hrs) 80 2,000hrs Work hours (gross) available per week = +520 maintenance Average sick leave deduction per week (=1person x 10hrs) -10 work exists. Average standard leave deduction per week (=1 person x 10hrs) -10 disruptions Find Weekly Average emergency work deduction typically (from history) at 50% of the -260 * The number of gross available (to be done outside regular backlog) weeks needed Other anticipated deductions (routine maintenance work needed) -40 to clear this work (backlog). Total hours deducted per week = -320 Overall craft capacity hours (realistically) available (from the gross) per week 520 – 320 = 200 Planned labour hours ready for scheduling (weekly) 2,000 Backlog Length = Backlog Length = = 10weeks true craft capacity (weekly) 200 Wiremann, T. (2008). Maintenance work management processes. New-York: Industrial Press Inc.  Fundamental Approaches to Maintenance Slide 18 ⚫Maintenance Approaches There are three main approaches (according to some). Methods range from the more basic (base of pyramid) to its peak (more complex) III. Predictive Level of complexity & direct cost Maintenance II. Preventive Maintenance I. Corrective Maintenance  Fundamental Approaches to Maintenance Slide 19 ⚫Corrective Maintenance (CM) Some possible scenario’s… “You don’t need to routinely flush out the radiator. Just wait until the temperature gauge indicates a high temperature! Lets hope it does not happen in the middle of a long journey” “The 100m long conveyor belt has broken. Its alright, we have one in store but it will take 10 hours to replace. Stop production!”  Fundamental Approaches to Maintenance Slide 20 ⚫Corrective Maintenance (CM) Corrective maintenance can be thought of being a passive maintenance approach that applies repairs after the event (failure) has been detected. This can also basically mean … Maintenance work is not always carried out at the most opportune time in such a manner such that it … avoids interruptions/shut-downs to machinery or processes during regular shut- down periods allows for these maintenance activities to have been planned and scheduled appropriately avoids potential hazards which can arise at the moment of failure reduces or minimises damage to infrastructure/equipment at the moment of failure minimises the costs associated with maintenance, particularly if the breakdown leads to the outsourcing of maintenance work Implementing (ongoing) Preventive Maintenance (PM) & Predictive Maintenance (PDM) strategy reduces the number corrective maintenance operations needed.  Fundamental Approaches to Maintenance Slide 21 ⚫Preventive Maintenance (PM) Some possible scenario’s… “Your plant operates four back-up diesel generators. You schedule a routine sump oil and filter change (on all machines) on the same day, every six months. This happens regardless of how many hours each generator had worked” “There is a sheet metal guillotine on your shop floor. Your maintenance crew can regularly inspect the blades for integrity once every three months”  Fundamental Approaches to Maintenance Slide 22 ⚫Preventive Maintenance (PM) Planned maintenance activities that involve some ongoing routine maintenance activities to avoid (to some degree) failures before them occurring. Preventive maintenance activities may extend to include: More appropriate design and installation of machinery and components Maintaining well organised history of machinery performance measure and repairs implemented Implementing regular inspections to machinery Ongoing service: lubrication, cleaning, overhauls Intended to avoid or minimise the occurrence of unexpected failures.  Fundamental Approaches to Maintenance Slide 23 ⚫Predictive Maintenance (PDM) Some possible scenario’s… “Your plant operates a dozen diesel generators. You collect oil samples from this machinery every quarter and analyse its viscosity and chemical constituents. With this data you identify when the next oil change (for a specific machine is due) or the period to the next machine overhaul ” “An underground mine has a (vibration) condition monitoring system. The system acquires data from critical gearboxes and analyses this. It is used to plan for maintenance operations during regular shut- downs and gives alarms of imminent part failure.  Fundamental Approaches to Maintenance Slide 24 ⚫Predictive Maintenance (PDM) Planned maintenance activities that use statistical tools and various instruments and tests to predict possible equipment failures. Predictive maintenance activities may extend to include … Real-time condition monitoring Noise and vibration analysis Chemical analyses of lubricants/chemicals Infra-red (IR) imaging The analyses of PDM can then help schedule PM activities The effective application of PDM maintenance strategies requires: Accurate identification of machinery Specially trained personnel in diagnostic techniques (in-house, or out-sourced) Specialised instrumentation (in-house, or out-sourced) A committed budget  Slide 25 Thank you