cambridge technicals in engineering - ocr · learning outcome (lo1) 10 learning outcome (lo2) 13...
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TECHNICALSCambridge
CAMBRIDGE TECHNICALS IN ENGINEERINGLEVEL 3 UNIT 21 – MAINTENANCE
DELIVERY GUIDEVersion 1
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CONTENTS
Introduction 3
Related Activities 4
Key Terms 5
Misconceptions 9
Suggested Activities:
Learning Outcome (LO1) 10
Learning Outcome (LO2) 13
Learning Outcome (LO3) 15
Learning Outcome (LO4) 17
Learning Outcome (LO5) 19
Learning Outcome (LO6) 21
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INTRODUCTIONThis Delivery Guide has been developed to provide practitioners with a variety of creative and practical ideas to support the delivery of this qualification. The Guide is a collection of lesson ideas with associated activities, which you may find helpful as you plan your lessons.
OCR has collaborated with current practitioners to ensure that the ideas put forward in this Delivery Guide are practical, realistic and dynamic. The Guide is structured by learning outcome so you can see how each activity helps you cover the requirements of this unit.
We appreciate that practitioners are knowledgeable in relation to what works for them and their learners. Therefore, the resources we have produced should not restrict or impact on practitioners’ creativity to deliver excellent learning opportunities.
Whether you are an experienced practitioner or new to the sector, we hope you find something in this guide which will help you to deliver excellent learning opportunities.
If you have any feedback on this Delivery Guide or suggestions for other resources you would like OCR to develop, please email [email protected].
Unit aimMaintenance, and maintenance engineering, are vital for all other aspects of engineering to function. From basic vehicle maintenance, to the increasingly complex devices, equipment, machinery and structures that are used in modern industry, the role of maintenance in keeping everything operating at optimum performance is crucial.
The aim of this unit is to develop learners’ knowledge and understanding of different maintenance strategies and operations, then to be able to plan and undertake maintenance operations themselves.
They will also be able to analyse maintenance data, develop an understanding of failure modes, and an understanding of how maintenance issues can inform future design.
Unit 21 Maintenance
LO1 Know about maintenance strategies and operations
LO2 Understand failure modes
LO3 Be able to analyse reliability-centred maintenance data
LO4 Be able to plan maintenance operations
LO5 Be able to undertake maintenance operations
LO6 Understand how maintenance issues can inform design
Opportunities for English and maths skills developmentWe believe that being able to make good progress in English and maths is essential to learners in both of these contexts and on a range of learning programmes. To help you enable your learners to progress in these subjects, we have signposted opportunities for English and maths skills practice within this resource. These suggestions are for guidance only. They are not designed to replace your own subject knowledge and expertise in deciding what is most appropriate for your learners.
English Maths
Please note
The timings for the suggested activities in this Delivery Guide DO NOT relate to the Guided Learning Hours (GLHs) for each unit.
Assessment guidance can be found within the Unit document available from www.ocr.org.uk.
The latest version of this Delivery Guide can be downloaded from the OCR website.
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This unit (Unit 21) Title of suggested activity Other units/LOs
LO1
Analysis and comparison of maintenance strategies
Unit 1 Mathematics for engineering
LO1 Understand the application of algebra relevant to engineering problems
Unit 1 Mathematics for engineering
LO6 Be able to apply statistics and probability in the context of engineering problems
LO2
Factors that contribute to failure Unit 2 Science for engineering LO4 Understand properties of materials
Common failure in mechanicals and electrical systems
Unit 2 Science for engineering LO4 Understand properties of materials
Effects of incorrect component selection Unit 2 Science for engineering LO4 Understand properties of materials
LO3
Introduction to reliability-centred maintenance Unit 1 Mathematics for engineering
LO1 Understand the application of algebra relevant to engineering problems
Unit 1 Mathematics for engineering
LO6 Be able to apply statistics and probability in the context of engineering problems
Sampling and standard deviation Unit 1 Mathematics for engineering
LO1 Understand the application of algebra relevant to engineering problems
Unit 1 Mathematics for engineering
LO6 Be able to apply statistics and probability in the context of engineering problems
MTBF, MTTF and MTTR Unit 1 Mathematics for engineering
LO1 Understand the application of algebra relevant to engineering problems
Unit 1 Mathematics for engineering
LO6 Be able to apply statistics and probability in the context of engineering problems
The Suggested Activities in this Delivery Guide listed below have also been related to other Cambridge Technicals in Engineering units/Learning Outcomes (LOs). This could help with delivery planning and enable learners to cover multiple parts of units.
RELATED ACTIVITIES
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KEY TERMSUNIT 21 – MAINTENANCE
Explanations of the key terms used within this unit, in the context of this unit
Key term Explanation
Anodic corrosion Anodic corrosion refers to part of the process that occurs during galvanic corrosion. It is a form of electrochemical corrosion process in which dissimilar metals in contact with each other (in an electrolyte) form an anode and a cathode. One metal acts as an anode which corrodes, and deposit collects on the cathode.
Chemical corrosion Chemical corrosion refers to the destruction of materials (usually metals) due to a chemical reaction with their environment or when in contact with other chemicals.
CMMS CMMS – Computerised Maintenance Management System – is a computerised software-driven system used to manage maintenance operations. This might include managing inventory, planning maintenance operation, and recording/ordering spare and replacement parts. It may also be used to gather data which is analysed to inform predicative maintenance.
Condition monitoring
Condition monitoring refers to the collection and analysis of information and data that represents the operational condition or status of a system. Condition monitoring may be undertaken manually or automatically using a computer. It is used to determine if a component or system is functioning correctly. Information might be collected through visual inspection, through X-Ray or ultrasonic inspection, or through gathering data including position, displacement, temperature, pressure etc.
COSHH Control of Substances Hazardous to Health (COSHH) is legislation that requires employers to control substances that are hazardous to health. It aims to prevent or reduce workers exposure to hazardous substances through identifying what the health hazards are and deciding how to prevent harm to health (risk assessment).
Design for assembly/maintenance
Design for assembly and/or maintenance involves using good design practices. These include using suitable materials, components, fastenings, location and accessibility of components etc. It also includes designing systems that are easy to assemble and maintain through the use of operator training.
Embrittlement Embrittlement is when a material becomes brittle. This may be due to structural changes to the material caused by heating, cooling, stress etc. Materials that become brittle may fail.
Expert system An expert system is a piece of software which uses databases of expert knowledge to offer advice or make decisions. Expert systems are sometimes used to analyse data that can be used in predictive maintenance.
Failsafe Failsafe refers to design features that allow a system to revert to a safe condition in the event of a failure or malfunction. Examples of failsafe mechanisms include dual-circuit brakes on a car and a safety gear on a lift (elevator).
Failure Failure refers to a component or system being able to perform the function or operation for which it was intended.
Fatigue Fatigue is caused when a material, component or system is subjected to repeated loading and unloading, and is more severe when the loading is outside the normal operating range.
Fouling Fouling refers to dirt, impurities or foreign matter/objects in a system that causes it to function incorrectly or fail.
Half-split fault finding method
The half-split method is a technique used in fault finding to locate defects with a few measurements. Essentially the technique involves splitting the circuit path into halves and troubleshooting from the middle of the first half then the second half and so on.
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Explanations of the key terms used within this unit, in the context of this unit
Key term Explanation
Incorrect component selection
Incorrect component selection means choosing a part, component or system that is unsuitable for a given application. Incorrect component selection may lead to a system that is unreliable, unsafe, difficult to assemble, difficult to maintain, difficult to recycle or that is uneconomic. Other factors may also arise through incorrect component selection.
Life cycle The life cycle of a produce or item covers the time from its manufacture to its recycling or disposal. Parts of a life cycle include: manufacture, useful life (including maintenance), breakdown/failure, de-commissioning, disposal and recycling. Costs associated with life cycle are sometimes termed the whole life cost.
Logging (data) Logging or data logging refers to the systematic collection of data for analysis. It is typically performed and analysed using a computer designed specifically for this task.
Lubrication (failure) Lubrication is the application of an oily or greasy substance in order to reduce friction between moving parts. When lubrication fails overheating will occur leading to damage or failure.
Maintenance Engineering maintenance is the application of engineering concepts to the optimization of equipment, procedures, and departmental budgets to achieve better maintainability, reliability, and availability of equipment.
Maladjustment Maladjustment refers to a component or system being in a condition or state in which it cannot perform the desired function or operation. Adjustment to prescribed parameters may correct this condition.
Maloperation Maloperation refers to a component or system not being used for the purpose for which it was intended, or being used deliberately outside its normal operating parameters.
Manual handling Manual handling often refers to the Manual Handling Operations Regulations. The regulations and their associated guidance (available from the Health and Safety Executive website) aim to reduce personal injury by poor or improper manual handling of items.
Modular design Modular design involves using standard modules that can be put together to form an overall system or device. Modular design allows for rapid design development, and may assist with maintenance by allowing failed modules to be replaced or repaired. An example of a modular design is the Dyson vacuum cleaner.
MTBF MTBF (Mean Time Between Failures) is a measure of how reliable a component, product or system is. For most components, the measure is typically in thousands or even tens of thousands of hours between failures.
MTTF Mean Time To Failure (MTTF) is the length of time a device or other product or plant is expected to last in operation before failure. MTTF is one of many ways to evaluate the reliability of equipment. In order to calculate MTTF the failure rate for the components or systems being considered is required – which might be linear, exponential etc.
MTTR Mean Time To Repair (MTTR) is a basic measure of the maintainability of repairable items. It represents the average time required to repair a failed component or system.
Overloading Overloading is the condition in which a component or system is operated outside of its normal parameters.
Planned Maintenance
Planned maintenance is defined as major repairs, organised and carried out with forethought, control and the use of records to a pre-determined plan.
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Explanations of the key terms used within this unit, in the context of this unit
Key term Explanation
Poka-Yoke Poka-Yoke is a Japanese term referring to the process for good design. It is a lean manufacturing process which also applies to maintenance. It means ‘mistake-proofing’ and involves incorporating features into a design to eliminate human error. An example is a plug and socket that can only be connected one way.
Poor training Poor training in the context of maintenance refers to poor training of an operator in the operation of a system or equipment, and to poor training of maintenance personnel.
Predictive maintenance
Predictive maintenance is a maintenance method in data is used to predict when and how failure might occur, and to make corrective actions before the failure.
Preventative maintenance
Preventive maintenance is a fundamental, planned maintenance activity designed to improve equipment life and avoid any unplanned maintenance activity. It includes inspection, detection, correction and prevention before failure occurs. An example of preventative maintenance is changing the oil in an engine.
Redundancy Redundancy is related to the inclusion of failsafe design features. It involves including extra and additional features into design to ensure correct operation in the event of parts of the system failing. An example of redundancy is an aircraft which can still fly should one engine fail.
Reliability-centred maintenance
Reliability Centered Maintenance (RCM) is a corporate level maintenance strategy that is implemented to optimize the maintenance program of a company or facility. The final result of an RCM program is the maintenance strategies that should be implemented on each of the assets of the facility.
Reliability-centred maintenance often involve the gathering, analysis and evaluation of data in order to predict when a failure might occur and to optimise maintenance.
Repair on demand Repair on demand is a maintenance strategy in which a component or system is allowed to fail, and then repair is made. Usually this repair is planned for and happens quickly.
Risk assessment A risk assessment is the process of identifying sensible measures to control the risks in the workplace. It involves identifying hazards and the risk they present (in terms of the severity of damage or injury the hazard would cause and how likely this is to occur), and putting in place measures to reduce or remove these risks.
Run to failure Run to failure is a maintenance strategy in which a component is system is run until it fails. It is then either repaired (repair on demand) or discarded if it has reached the end of its useful life.
Safe work method statement / method statement
A method statement (sometimes called a safe work method statement or SWMS) is a part of a workplace safety plan. It is a document that gives specific instructions on how to safely perform a work related task, or operate a piece of plant or equipment.
Sampling Sampling refers to the collection of data at regular intervals in order to inform maintenance strategies. It is commonly used in reliability-centred maintenance. Sampled data is analysed using statistical techniques.
Scheduled maintenance
Scheduled maintenance is another name commonly used for planned maintenance.
Seizure Seizure is the failure of a mechanism caused by touching parts, which should move relative to each other, becoming locked together preventing movement. Seizure commonly affects components such as bearings and gears.
Six point fault finding method
The six point fault finding technique has six steps: 1. Test the system, i.e. make measurements or collect other evidence, 2. Analyse the reading, 3. Locate fault based on analysis, 4. Determine the original cause of the fault. (i.e. find a method to prevent recurrence), 5. Repair the fault, 6. Retest the system.
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Explanations of the key terms used within this unit, in the context of this unit
Key term Explanation
Standard component/part
A standard component or part is a component/part that conforms to an established industry specification or standard. Examples of standard parts include nut and bolt sizes, fuse ratings, cable sizes etc.
Standard deviation Standard deviation is a statistical technique used to determine how much the members of a group (or set of sampled data) deviate from the mean value.
Stress fracture A stress fracture in a material is a fracture caused by repeated mechanical stress.
Vibration Vibration refers to a shaking movement in a system, which might be periodic or otherwise. Vibration may cause a system to function incorrectly, or may lead to failure.
Visual inspection Visual Inspection means inspection of equipment using either or all of raw human senses such as vision, hearing, touch and smell and/or any non-specialized inspection equipment.
Wear For mechanical components wear is erosion or deformation that takes place between two moving surfaces in contact. It may cause components and systems to eventually perform incorrectly.
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Some common misconceptions and guidance on how they could be overcome
What is the misconception? How can this be overcome? Resources which could help
Statistics - variance, standard deviation (understanding the difference between population and sample data)
Learners may already be confident in calculating mean, mode and median. Variance and standard deviation are an extension of this. The formula for standard deviation differs for population and sample data, and teachers may wish to reinforce this difference.
http://www.mathsisfun.com/data/standard-deviation.html
Understanding the difference between and significance of MTBF, MTTF and MTTR
Learners often confuse the terms MTBF, MTTF and MTTR and do not appreciate the results of calculations.Teachers may reinforce understanding by providing a range of examples for learners to solve, including interpretation of results.
http://www.reliabilityeducation.com/ReliabilityPredictionBasics.pdf
Understanding the difference between risk assessment and safe work method statements
Although often undertaken together, learners often confuse a method statement with a risk assessment. The explanations and definitions on the Health and Safety Executive (HSE) website might prove useful.
http://www.hse.gov.uk/risk/faq.htm
MISCONCEPTIONS
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SUGGESTED ACTIVITIESLO No: 1
LO Title: Know about maintenance strategies and operations
Title of suggested activity Suggested activities Suggested timings Also related to
Introduction to maintenance strategies
Teachers could begin the topic of maintenance with a general introduction. Reasons for performing maintenance include: assurance of the safety and availability of systems and devices, and ensuring that they are performing optimally.
Learners could undertake a basic investigation of engineering maintenance including the areas and sectors in which it is undertaken.
Web-based resources such as the following online magazine which includes a number of industrial case studies may prove useful: http://www.maintenanceonline.co.uk/home.asp
2 hours
Planned / scheduled maintenance
Planned (or scheduled) maintenance involves performing maintenance at pre-determined intervals which is planned in advance.
The following video shows the planning process for maintenance within a power plant – where a machine is shut down for planned maintenance: http://www.maintenanceonline.co.uk/home.asp
The video also refers to preventative maintenance being performed as part of the maintenance process.
Learners could investigate other instances of planned maintenance – such as a service on a car, aircraft or other vehicle or plant. Advantages and disadvantages could be considered.
2 hours
Preventative maintenance Preventative maintenance may be considered as a part of a planned maintenance regime. It includes inspections, regular cleaning, checking and replacing consumables (often before failure) and operator training to identify potential faults.
The following video shows preventative maintenance for a Caterpillar earth mover: http://www.youtube.com/watch?v=cyj2fhi1wwk
Learners could investigate the advantages and disadvantages of preventative maintenance – and could use suitable case study examples.
The connection between planned and preventative maintenance could be explored.
2 hours
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Title of suggested activity Suggested activities Suggested timings Also related to
Predictive maintenance Predictive maintenance involves predicting component or system failure, and taking action before a breakdown. It involves evaluating the condition of a system or component using condition monitoring techniques.
The following video illustrates the use of data to inform predictive maintenance: http://www.youtube.com/watch?v=cyj2fhi1wwk
Learners could explore how data and condition monitoring is used in predictive maintenance – including the advantages and disadvantages of using this maintenance strategy.
2 hours
Repair on demand / run to failure
Run to failure is a maintenance strategy in which a component or system is run until it fails, and then discarded or repaired.
Examples of components that are run to failure include car tyres and electric lamps.
Learners could investigate the advantages and disadvantages of adopting run to failure strategies – which might include analysing a number of case studies.
The following explains run to failure maintenance: http://www.maintenanceassistant.com/run-to-failure-maintenance/
2 hours
Analysis and comparison of maintenance strategies
Learners could use information gathered about various maintenance strategies and make a comparison.
Factors that often influence the selection of a maintenance strategy include cost (e.g. for maintenance or associated with loss of use) and availability (including safety).
Others factors include: effectiveness, predictability and staff/training requirements.
Different maintenance strategies are more suitable for different situations (e.g. plants, processes or systems).
Learners could compare the advantages and disadvantages of different maintenance strategies against selected criteria. Teachers might also develop simple numerical problems involving cost and availability for learners to solver.
The following explains how maintenance strategies might be compared using the metrics of cost and availability. Teachers might use this resource to selectively develop suitable examples: http://www.reliasoft.com/newsletter/v6i2/maintenance_strategies.htm
2 hours Unit 1 LO1Unit 1 LO6
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Title of suggested activity Suggested activities Suggested timings Also related to
Use of computers in maintenance
The use of software to manage maintenance is now commonplace. Software might be used for managing maintenance and for the tracking and ordering of parts including spare parts.
The following explains the features of a Computerised Maintenance Management System (CMMS) system: http://www.maintenanceassistant.com/cmms/
Learners could investigate CMMS systems and how they might be used to manage and plan maintenance operations.
2 hours
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LO No: 2
LO Title: Understand failure modes
Title of suggested activity Suggested activities Suggested timings Also related to
Factors that contribute to failure
See Lesson Element Factors that contribute to failure
Factors that contribute to system and component failure include: maladjustment, maloperation, stress fracture, fatigue, wear, embrittlement, overloading, seizure, anodic and chemical corrosion, lubrication failure, fouling, vibration and poor training. Components and systems might also be deliberately run to failure.
Teachers may be able to show or demonstrate to learners a number of failure modes.
The following video shows typical failure modes of materials (http://www.youtube.com/watch?v=85HxmnLEkwM) and the following NASA website includes case studies illustrating modes of system failure: http://nsc.nasa.gov/sfcs/
Further videos show the effects of poor lubrication (http://www.youtube.com/watch?v=3WLOccckJ5o) and timing belt failure (http://www.youtube.com/watch?v=qPApHQ0tGBk)
Learners could find examples of different type of failure and explain reasons for its cause in each case.
2 hours Unit 2 LO4
Common failure in mechanical and electrical systems
Common failures in mechanical and electrical systems include: defective relay contacts, worn motor brushes, lack of or too much oil, dirt/grime, corrosion, contamination and incorrect belt tension. There are many other examples.
Teachers could illustrate a number of common failures to learners, either practically or through the use of videos.
The following videos show cooling failure caused by dust (http://www.youtube.com/watch?v=dofGz438gts) and worn motor brushes (http://www.youtube.com/watch?v=-pTDF6R9-RA&list=PL5iKef2TlYXt_GGKNrwAlgtpgbSrZ2CKA)
3 hours Unit 2 LO4
SUGGESTED ACTIVITIES
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Title of suggested activity Suggested activities Suggested timings Also related to
Effects of incorrect component selection
Incorrect component selection can lead to systems that fail to work, that are unreliable or that are unsafe.
Parts might be incorrectly selected at the design, manufacture or installation stages, or incorrectly replaced during maintenance.
Teachers could use case studies to illustrate the consequences of incorrect component selection.
The following case studies show a car recall caused by incorrectly selected steering bolts (http://www.leftlanenews.com/nissan-recalls-2014-rogue-crossovers-over-incorrect-steering-bolts.html) and a fire caused by incorrect fuse selection (http://poststar.com/news/local/incorrect-fuse-played-role-in-fort-edward-fatal-fire/article_27d63092-afc7-11df-9580-001cc4c002e0.html).
Learners could investigate further the consequences of incorrect component selection – and how it might be avoided in maintenance operations.
2 hours Unit 2 LO4
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LO No: 3
LO Title: Be able to analyse reliability-centred maintenance data
Title of suggested activity Suggested activities Suggested timings Also related to
Introduction to reliability-centred maintenance
Reliability Centered Maintenance (RCM) is a corporate level maintenance strategy that is implemented to optimize the maintenance program of a company or facility. The final result of an RCM program is the maintenance strategies that should be implemented on each of the assets of the facility.
Reliability-centred maintenance often involves the gathering, analysis and evaluation of data in order to predict when a failure might occur and to optimise maintenance. Corrective actions are then taken to mitigate against failure before it happens.
Teachers could begin with an introduction to reliability-centred maintenance – considering its history, application, advantages and disadvantages.
The following website might prove a useful starting point and asks seven fundamental questions: http://www.reliabilityweb.com/art08/7_questions_rcm.htm
1 hour Unit 1 LO1Unit 1 LO6
Sampling and standard deviation
Data used for evaluating reliability is often sampled and analysed using mathematical techniques. These include common statistical tools such as mean, mode, median and standard deviation. The number of samples in the data set also affects reliability of the data.
Teachers could recap previous mathematical knowledge of learners in the area of statistics and sampling – including the presentation of information using graphs.
Teachers could also develop or adopt problems for learners to solve that are directly relevant to maintenance.
2 hours Unit 1 LO1Unit 1 LO6
SUGGESTED ACTIVITIES
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Title of suggested activity Suggested activities Suggested timings Also related to
MTBF, MTTF and MTTR
See Lesson Element MTBF, MTTF and MTTR
Mean Time Between Failures (MTBF), Mean Time To Repair (MTTR) and Mean Time To Failure (MTTF) are commonly used metrics that inform reliability-centred maintenance strategies.
Teachers could introduce learners to the definition of these terms. Web-based resources might prove useful – such as the following which explains the basics of reliability prediction: http://www.reliabilityeducation.com/ReliabilityPredictionBasics.pdf
Teachers could also introduce learners to the concept and the well-known bathtub curve (see http://ftp.automationdirect.com/pub/Product%20Reliability%20and%20MTBF.pdf )
Problems might be developed for learners to solve for MTBF, MTTR and MTTF.
4 hours Unit 1 LO1Unit 1 LO6
Use of software in maintenance
Software is often used to gather and analyse data used in reliability-centred maintenance. Computerised Maintenance Management Systems (CMMS) can often monitor and log data, predict failure and can be used in the planning of maintenance operations. The planning aspect has been previously considered.
Learners could investigate and evaluate how software can be used to gather and analyse data in reliability-centred maintenance.
The following is a comparison of CMMS software with links to suppliers websites: http://www.softwareadvice.com/uk/cmms/
If access to suitable software is available, it may be possible for learners to investigate a CMMS practically.
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LO No: 4
LO Title: Be able to plan maintenance operations
Title of suggested activity Suggested activities Suggested timings Also related to
Using circuit diagrams and data sheets
Being able to read and interpret circuit diagrams is a key part of being able to perform fault-finding maintenance on electrical systems. Being able to interpret data sheets for both electrical and mechanical engineering components and systems (e.g. a motor, clutch, bearing, fastener etc.) is also invaluable.
Teachers could provide learners with a basic introduction to reading circuit diagrams – including the identification of component symbols (see http://www.rapidtables.com/electric/electrical_symbols.htm for typical circuit symbols and http://www.instructables.com/id/HOW-TO-READ-CIRCUIT-DIAGRAMS/ on how to read circuit diagrams).
Learners could practice reading simple circuit diagrams, and interpreting data sheets.
2 hours
Fault finding techniques, testing and determining fault location
Fault finding techniques used in maintenance include visual inspection, and operational methods such as the half-split method and the six point fault finding technique (test, analyse, locate fault, determine cause, repair, re-test).
Testing also involves the use of manuals, data sheets and fault finding data leading to expected values.
Teachers could introduce learners to a range of fault-finding techniques – explaining how they can be applied and their advantages and disadvantages.
Where possible, practical activities might be used. These could be reinforced with web-based resources such as the follow showing and explaining visual inspection: http://www.youtube.com/watch?v=9VYA9ufb4Jc, http://www.youtube.com/watch?v=xDajhAzG16k
Half-split method: http://www.allaboutcircuits.com/videos/28.html
Six-point technique: http://blog.gice.in/the-six-step-problem-solving-model/
3 hours
SUGGESTED ACTIVITIES
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Title of suggested activity Suggested activities Suggested timings Also related to
Using standard components and tools
The use of standard components in the design of components and systems allows for easy replacement and repair and for the use of standard tools and equipment to perform maintenance operations.
Learners could investigate and explain the benefits of having standards tooling in maintenance operations (see http://www.technologystudent.com/prddes1/stand1.html)
Learners might also consider the disadvantages of using standard components and tooling.
1 hour
Planning maintenance operations
Planning is an essential part of performing maintenance operations. This includes safe access to plant and equipment, ensuring that the correct resources and replacement parts are available, and that the correct sequence of operations is followed.
Planning is vital to performing a successful maintenance operation.
Learners could produce a plan for a maintenance operation on equipment or plant. The following guide from the Health and Safety Executive (HSE) might prove useful: http://www.hse.gov.uk/toolbox/machinery/plant.htm
Learners could logically consider health and safety requirements at this stage (e.g. safe work method statements and risk assessment) with reference being made to the guidance on the HSE website – although this is considered later in the unit.
3 hours
Using expert systems Expert systems that can analyse the behaviour of systems based on data to predict failure or diagnose fault conditions are commonplace. They might be used in complex systems, such as an aeroplane engine, or relatively simple systems such as automotive diagnostics.
Learners could investigate the application and benefits of expert systems. The following provides an introduction to expert systems: http://www.referenceforbusiness.com/encyclopedia/Ent-Fac/Expert-Systems.html and the following case studies of the use of expert systems in Rolls Royce engines: http://www.rolls-royce.com/about/our-technology/enabling-technologies/engine-health-management.aspx#sense
If access to suitable resources is available, learners might be able to explore an expert system practically.
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LO No: 5
LO Title: Be able to undertake maintenance operations
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Safe working Planning for and applying safe working practices when performing maintenance operations is extremely important in order to avoid injury and damage.
The Health and Safety Executive website provides guidance on how to achieve safe working through the production and use of safe work method statements and risk assessments. See http://www.hse.gov.uk/risk/faq.htm (method statements and risk assessment).
Teachers could explain to learners the processes for developing safe work method statements and risk assessments.
Learners could develop a method statement and risk assessment for a practical maintenance operation. This might be undertaken as part of the more detailed planning process, to include sequence of operation, parts and tooling etc.
2 hours
Mitigating hazards Risk assessments identify hazards and the risks they present. The level of risk can be reduced by militating against hazards. Techniques for mitigating against hazards include: visual inspection of equipment, electrical testing of equipment, use of spill response systems, Control of Substances Hazardous to Health (COSHH) and correct manual handling.
Learners could investigate hazard mitigation techniques.
Web-based resources might prove useful such as:
http://www.youtube.com/watch?v=TdeU6UCCfTY (PAT testing of electrical equipment), http://www.hse.gov.uk/coshh/ (COSHH), http://www.hse.gov.uk/toolbox/manual.htm (manual handling) and http://www.hse.gov.uk/comah/sragtech/techmeasspill.htm (emergency response). Learners could consider hazard mitigation alongside maintenance plans previously produced.
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Performing maintenance operations
Learners could use a maintenance plan to perform a maintenance operation practically on equipment or plant.
Maintenance might involve electrical, mechanical, electromechanical, pneumatic or hydraulic operations.
It might also involve the use of appropriate tools and techniques.
Learners could keep some form of logbook of the maintenance operation, comparing activities against a plan and suggesting improvements.
Teacher guidance will be required when performing maintenance operations practically, as will the observance of health and safety procedures.
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LO No: 6
LO Title: Understand how maintenance issues can inform design
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Design considerations - component
It is common practice to use standard, universally available parts in the design of systems. This allows for easy, cost effective manufacture and maintenance.
Learners could investigate the advantages and disadvantages of using standard components in design.
The following article provides an argument for not using standard parts which might be useful to stimulate discussion: http://machinedesign.com/engineering-education/industrial-design-hidden-cost-standard-parts
1 hour
Design considerations - assembly and maintenance
There are many design considerations that can be taken to assist with assembly and maintenance.
These include ensuring components that are regularly replaced are easy to handle, positioning components that often need to be maintained at an easily accessible location, ensuring maintenance points are close to each and allowing for the use of standard tools.
Another technique is termed ‘Poka-Yoke’ which is a design process to ensure components can only be located in a certain orientation (see http://www.thetoyotasystem.com/lean_inventions/poka_yoke-you-can%E2%80%99t-go-wrong.php)
Learners could explore and evaluate a range of good and poor design techniques in relation to assembly and maintenance.
2 hours
Using modular design Modular design allows for standard and common modules to be used across a range of products, and for easy maintenance by allowing modules to be simply replaced.
One example of a modular design is the Dyson vacuum cleaner – which is easy to maintain.
The Dyson Foundation website contains a range of useful resources for teachers - http://www.jamesdysonfoundation.co.uk/
Learners could investigate the advantages of applying modular design, and might explore case studies such as the Dyson vacuum cleaner.
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Failsafe design and redundancy
See Lesson Element Failsafe design and redundancy
Designs for safety-critical systems often have failsafe mechanisms built into them such that if a failure occurs then the system reverts to a safe condition. Critical systems may also have redundancy built in, so that the system may continue to function correctly in the event of failures.
Learners could investigate systems that include failsafe design features (such as a roller coaster or car braking system) and how this is achieved. Redundancy could also be explored – including its link to fail safe design.
The following article discusses the principles of failsafe design, and may be a useful starting point: http://www.aiche.org/chenected/2011/02/principle-fail-safe
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Life time considerations All products have a life cycle – from initial manufacture to end of life disposal. The following website gives examples of the lifecycle for different products: http://www.technologystudent.com/prddes1/lifecy1.html
While some products and systems are designed for no maintenance (i.e. run to failure) others are designed to be maintained throughout their working life. Data collected through the life cycle of a product can be useful for informing future designs, and also in determining the effects of whole life cost.
Learners could investigate the life cycle of products and systems, including those that are maintained. Maintenance (and its associated cost) could also be considered as part of any analysis.
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