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...

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 … Predictive Maintenance (CHP 4) (Stephens, 2010) 4.1 Introduction [to predictive maintenance] 4.1.1 Definition of Predictive Maintenance 4.1.2 PDM’s Reliance on Science and Technology 4.1.3 Decision Factors Regarding PDM 4.1.4 PDM’s Quantitative Nature 4.1.5 Approaches to Data Collection 4.1.6 Data Analysis 4.2 Predictive Maintenance Techniques 4.2.1 Vibration Analysis 4.2.2 Chemical Analysis 4.2.3 Tribology 4.2.4 Thermography 4.2.5 Ultrasonic Techniques  This lecture in a nutshell This lecture will basically … List the four elements which can help develop and apply predictive maintenance Present some indicators of how widespread predictive maintenance is, in relation to other maintenance strategies Introduce some predictive maintenance techniques and some of the outcomes of applying these  Predictive Maintenance Slide 5 An Introduction to Predictive Maintenance The definition below shows four elements can be needed in predictive maintenance. Predictive Maintenance: “… applies various technologies and analytical tools to measure, and monitor various system and component operating characteristics and to compare these data with established and known standards and specifications in order to predict (forecast) system or component failures”. (Stephens, 2010) Predictive (or condition based maintenance) is considered the more complex of the three fundamental approaches to industrial maintenance. Principles of Industrial Maintenance Edith Cowan University 2018 Predictive Maintenance Slide 6 III. Predictive Level of complexity & direct cost Maintenance II. Preventive Maintenance I. Corrective Maintenance Different levels of complexity and associated cost lead to varying extents for applying these (three) fundamental approaches. Typical (actual) application percentages (based on source/2010 data) are: Corrective maintenance … just over 50% Preventive maintenance … just over 30% Predictive maintenance … just over 10% Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 7 An Introduction to Predictive Maintenance A comparison between “World Class” levels of applying PDM and those in North American industry. Type of Industry Actual World Class Assembly 7% 39% Distribution 10% 30% Manufacturing (Large) 12% 30% Manufacturing (Small) 12% 32% Process 15% 42% Consultants’ Opinion 15% 38% Weighted Average 13% 35% Source: Table 4-1. Stephens, Matthew P. (2010) Productivity and reliability-based maintenance management. New Jersey: Pearson Education, Inc. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 8 An Introduction to Predictive Maintenance Amongst the more apparent difference between CM, PM, and PDM are that: CM is remedial looks at returning equipment/systems to their original operating state … after failure has occurred PM is precautionary attempts to minimise the occurrence of CM through ongoing service PDM is forecasting (predictive) looks at measuring a condition (current equipment status) … then extrapolates this data into the future … uses this information (for example) to predict the next oil change … and uses the data to identify potential (early) solution steps also termed “Condition Based Maintenance” Predictive Maintenance The need to collect data, analyse it and use it to predict future events means that the costs associated with PDM are quite high (more time, higher skill level needed, dedicated instrumentation, greater commitment from management) compared to other maintenance approaches. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 9  Predictive Maintenance Data Collection PDM techniques and analyses are quantitative in nature. This requires: Accurate recording of conditions or operating parameters Collecting useful data Maintaining the integrity of data Calibration of measurement instruments Recording time, location, approach, and implementer of the collected data Data collection approaches are: Fixed devices Source: https://www.sonotec.eu/ Remote collection systems Suitable for harsh environment Portable devices Can be taken from one piece to another piece of equipment Principles of Industrial Maintenance Edith Cowan University 2018 Quiz Slide 10  Which of the following item(s) is correct? The PDM analysis … o maybe chemical, engineering, statistical, and likely a combination of all. o may require comparison of collected data with stablished standards or a baseline. o may lead to corrective actions. o may lead to no actions. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 11 Techniques of Predictive Maintenance Some common PDM techniques are: Vibration based (e.g., rotating parts like shafts and bearings) Chemical based (e.g., lubricants such as oils) Tribological based (e.g., by looking at wear debris) Thermographic (e.g., via applying methods such as IR imaging) Ultrasonic testing (e.g., to identify emerging sub surface flaws and cracks) Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 12 Vibration Based Methods - Introduction Subject to economic feasibility and degree of criticality, vibration levels of rotational equipment may require regular monitoring. Typical causes of (excessive) vibration: Imbalance of rotational parts Source: https://nttinc.com/ Misalignment Bearing defects Belt defects The early signs of failure can be picked up by vibration sensing instrumentation. Effectively administered vibration based analyses can detect and warn against a deteriorating (machine) condition much sooner than thermography (infra-red imaging). Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 13 Vibration Based Methods – Vibration Analysis Please watch the video from 00:00 to 07:45. Video URL: https://youtu.be/Vj1xmze3GlE Principles of Industrial Maintenance Edith Cowan University 2018 Quiz Slide 14 In your opinion, to reduce the errors associated with vibration based methods what considerations are needed? Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 15 Vibration Based Methods – Influencing Factors Levels of vibration will vary based on equipment type and operating conditions. Normal’ levels of vibration of some plant equipment are generally viewed as being higher than others. These equipment include: Pumps Compressors Reciprocating equipment Main factors affecting level of vibration from different parts/equipment: Size Stiffness Weight Foundation rigidity Surrounding plant equipment (linked to these via groundwork, ducts, pipes) Source: https://www.reliableplant.com/ Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 16 Vibration Based Methods – Factors Affecting Vibration ISO Standard 2372 (machinery classes, velocity range limits)* General guidelines and standards of vibration monitoring (equipment classifications). Four levels of vibration severity … A, B, C, D. What may be considered an acceptable level of vibration, varies based on the class of equipment. Vibration velocity reported (units: mm/s, ips) effectively represents severity of forces on bearings: The vibration severity on a machine, one measure is … “… maximum root-mean-square of the vibration velocity”. (Stephens, 2010) A (general) definition of ‘root-mean-square is:  vi v  N N v 2 i root mean square v'  i 1 mean  v  i 1 N 1 N * Different standards or guidelines may be applied in specific settings and these are all subject to change/renewal. Check the standards/guidelines applicable. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 17 Vibration Based Methods – Factors Affecting Vibration ISO Standard 2372 (machinery classes, velocity range limits) Source: Table 4-2. Stephens, Matthew P. (2004) Productivity and reliability-based maintenance management. New Jersey: Pearson Education, Inc. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 18 Vibration Based Methods – Factors Affecting Vibration ISO Standard 2372 (machinery classes, velocity range limits) Refer to standard for full details. The following summary is based on Stephens (2010). Machinery Class I Small sized machines Individual machine parts at normal operating conditions. Electric motors (upto 15kW output) Machinery Class II Medium sized machines Electric motors (15kW-75kW output) “without special foundations” Machines upto 300kW “with special foundations” Machinery Class III Large sized machinery with rotation masses “mounted on rigid heavy foundations that are relatively stiff in the direction of vibration measurement” Machinery Class IV Large sized machinery with rotation masses “mounted on foundations that are relatively soft in the direction of vibration measurement” Turbo generator sets (light substructures) Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 19 Vibration Based Methods – Influencing Factors More advanced failure stages yield more significant vibration levels, become increasingly apparent and may subsequently result in extensive damage to machine elements. Source: Table 4-3. Stephens, Matthew P. (2010) Productivity and reliability-based maintenance management. New Jersey: Pearson Education, Inc. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 20 Vibration Based Methods – Analyses: Vibration Trends and Signatures Trend ‘Critical region’ For example, vibration level: >0.628ips ‘First alarm region’ For example, vibration level: 0.314- 0.628ips Period of operation Signature Source: Figure 4-1. Stephens, Matthew P. (2010) Productivity and reliability-based maintenance management. New Jersey: Pearson Education, Inc. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 21 Vibration Based Methods – Analyses: Vibration Trends and Signatures Source: Figure 4-5. Stephens, Matthew P. (2004) Productivity and reliability-based maintenance management. New Jersey: Pearson Education, Inc. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 22 Vibration Based Methods – Analyses: Vibration Trends and Signatures Peaks within the vibration signature (along the y-axis) can be linked to a different components operating at their own speeds. For example: Fan motor, …(some number of) cycles/min. Fan blades, …(some number of) cycles/min. Drive shaft, (some number of) cycles/min. This requires the complex task of accurately decomposing these signatures into their individual components, attributing these to the different sources and also monitoring their progression with time for failure prediction. Vibration based condition monitoring is a much wider and complicated topic. This is an introduction only. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 23 Vibration Based Methods – Analyses: Vibration Trends and Signatures Please watch the video from 07:45 to 16:25. Video URL: https://youtu.be/Vj1xmze3GlE Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 24 Chemical Analyses Applied to machine coolants and lubricants can provide valuable insights into operating conditions. As such remedial steps may be taken to preserve machine health. Common Chemical Analysis Techniques Spectrographic Spectroscopic methods to identify type and quantity of constituents in a sample Method can help detect metallic debris in machine oil due to wear, airborne pollutants Oil suppliers supply baseline spectra (for their lubricants) for comparison Periodic analyses discover changing constituents and identify trends Oxford Instrument spectrometer Source of images: https://www.azom.com/article.aspx?ArticleID=12874 Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 25 Chemical Analyses: Common Predictive Maintenance Methods Spectrographic Elements detectable through spectroscopic methods (in predictive maintenance) and some of their potential sources. Source: Table 4-4. Stephens, Mathew P. (2004) Productivity and reliability-based maintenance management. New Jersey: Pearson Education, Inc. Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 26 ChemicalAnalyses: Common Predictive Maintenance Methods pH Monitoring To establish acidity or alkalinity (base) levels Numerical value: 0 to 14 0 indicates very strong acidity 7 indicates a neutral solution (e.g., water) 14 indicates very strong alkalinity Some pH monitoring devices Machine oils and lubricants will have OEM specified pH levels and machine manufacturers may likewise specify what pH levels are needed in these fluids. Broken machine gaskets, seals, lubricant deterioration can lead to changes in pH levels. Periodic monitoring can help avert more serious damage Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 27 Tribological Analyses Help clarify the effects of surface friction on material degradation (wear). Surface friction also has implications on the rate of energy dissipation between moving parts. Control of friction important aspects of both preventive and predictive maintenance programs. Particles (dust) in pneumatic systems Particles trapped in hydraulic systems Solid debris (wood, sand, metallic) entrapped between sliding surfaces As such, tribology is an important tool in the analysis of wear mechanisms where relative motion exists. Bearings are good examples Surface properties of bearing surfaces, and their modification, have tribological implications Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 28 Tribological Analyses Please watch the video related to Tribology analysis. Video URL: https://youtu.be/mZMnq_BRPlM Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 29 Thermography A combination of methods where temperature is the prime indicator for detecting changed system status, health and soundness. Infra Red Methods Imaging Pyrometers Adhesive tapes Temperature sensitive paints and tags Probe based methods (thermocouples) Infra Red Methods Based on measuring heat radiation from bodies Some thermal imaging devices Radiation occurs in the infra red spectrum Radiated energy is correlated to a temperature for a given (set) surface emissivity 2-Dimensional representation of temperature can be formed Temperatures measured are surface (not core) temperatures Applying the methods requires skill even though the instruments appear basic Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 30 Thermography Infra Red Methods 2-Dimensional representations help provide a visual representation of not only temperature distribution at the surface, but also localised hot spots. Applied to analyses of … Mechanical systems alignment problems bearing defects/failures poor lubrication Loose parts (vibrating or showing relative motion) Electrical electrical contacts (loose, oxidised) overheating components damaged wires/lines Chemical processes Temperature distributions on solid surfaces Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 31 Thermography Please watch the video related to Thermography analysis. Video URL: https://youtu.be/GP95xTBqYXw Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 32 Ultrasound Methods Frequencies beyond the normal hearing spectrum (shortwave, directional). “Sonic signatures” generated by equipment Changed signals refer to variations in an operating condition Ultrasonic methods of detection applied to … Fluid leaks from lines (hydraulic, pneumatic) Electrical arcs pre-empt detection by other methods such as thermography and vibration Two measurement principles exist Echo based instrument/probe emits ultrasonic waves and receives echoes Analyse: thickness (manufacture, corrosion), cracks Detection based Localisation of leaks Principles of Industrial Maintenance Edith Cowan University 2018  Predictive Maintenance Slide 33 Ultrasound Methods Please watch the video related to Ultrasonic testing. Video URL: https://www.youtube.com/watch?v=41i0ciqqYYM Principles of Industrial Maintenance Edith Cowan University 2018 Quiz Slide 34  Which of the following item(s) is not correct? o Vibration analysis is an important method to detect early warning signals and prevent possible failure(s). opH monitoring can provide useful information about internal condition of the equipment. oUltrasound frequencies often can be detected after vibration or temperature levels. oInfrared thermography can be used to detect failure areas under the ground surface. Principles of Industrial Maintenance Edith Cowan University 2018 Predictive Maintenance Slide 35 Thank you Principles of Industrial Maintenance Edith Cowan University 2018