Mechanical Engineering Level 2 NVQ

Transcription

1

2 Mechanical Engineering Level 2 NVQ

3 Mechanical Engineering Level 2 NVQ David Salmon Penny Powdrill Newnes OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI

4 Newnes An imprint of Butterworth-Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Woburn, MA A division of Reed Educational and Professional Publishing Ltd First published 2002 David Salmon and Penny Powdrill, 2002 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1P OLP. Applications for the copyright holder s written permission to reproduce any part of this publication should be addressed to the publishers British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN Composition by Laserwords Private Limited, Chennai, India Printed and bound in Great Britain

5 Contents Preface Acknowledgements Chapter/Unit references Introduction for Candidates Introduction for Trainers vii ix x xi xiii 1 Working safely in an engineering environment 1 2 Developing yourself and working with other people on engineering activities 38 3 Communicating using engineering drawings 71 4 Communicating technical information in the workplace 98 5 Identifying and selecting engineering materials Checking workpieces for accuracy Marking out for engineering activities Fitting using hand skills Machining engineering materials by turning 263

6 vi contents 10 Machining engineering materials by milling Using computer software packages to assist engineering activities Problem solving 414 Appendix I Millimetres to inch conversions 419 Appendix II Inch to millimetres conversions 420 Appendix III Tapping sizes for common threads 422 Appendix IV Appendix V Appendix VI Length of chords for various pitch circle diameters 424 Example orthographic drawing (first-angle projection) 425 Example orthographic drawing (third-angle projection) 426 Appendix VII Drilling speeds and feeds 427 Appendix VIII Spindle speeds for turning and milling 429 Appendix IX Feed rates for milling 430 Appendix X Reaming allowances 432 Appendix XI Torque wrench settings 433 Appendix XII Sample standard forms 435 Appendix XIII Some useful maths for engineers 437 Appendix XIV Risk assessment form 439 Appendix XV Sample accident reporting form 441 Appendix XVI Work planning sheet 443 Index 445

7 Preface Mechanical Engineering: Level 2 NVQ has been published in response to the new Performing Engineering Operations occupational standards. The book has been written with the needs of modern apprentices, trainees and college students in mind and is designed to update and extend David Salmon s books, Engineering: Mandatory Units and Engineering: Mechanical Units. Mechanical Engineering: Level 2 NVQ takes an interactive, studentcentred approach and contains large numbers of training exercises designed to be used with portfolio building in mind. By working through the exercises the trainee will be able to demonstrate both underpinning knowledge and practical ability. There is space provided for witness testimony, and trainees are also encouraged to produce computer-generated material for use as evidence for Information Technology Key Skills. The book is based around the EMTA standards for Performing Engineering Operations, incorporating the three mandatory units, two support units and three optional units with the objective of providing a solid background of knowledge and skills in mechanical engineering. The completed book will provide evidence for Level 2 NVQs awarded by EAL (EMTA Awards Ltd) or City & Guilds (scheme 2251). Additionally, all six Key Skills are addressed with assignments designed to allow a candidate to acquire expertise at Level 2. The authors hope that the relatively informal style has produced a text that is user-friendly and one that encourages its readers to enjoy their training. David Salmon Penny Powdrill

8 Acknowledgements The authors and publisher are grateful to the following companies for their help during the preparation of this text, and for permission to reproduce copyright materials: Delphi Lockheed British Motor Heritage Trust Britool Limited Cincinnati Milacron Danaher Tool Group Domer Tools Ford Motor Company Global Supplies Catalogue Hattersley Newman Hender Ltd HSE Books Hydra Tools International Kennametal Hertel EDG Ltd L.S. Starrett company Mitutoyo UK Ltd Moore & Wright Ltd Nelsa Machine Guarding Systems Ltd Pratt Burnerd International Rubert & Co Silvaflame Co. Ltd The 600 Group WDS Standard Parts Thanks also to Mr. R.L. Timings for allowing the inclusion of some illustrations from his engineering books which are published by Pearson Education, and the Wyedean Insurance Company.

9 Chapter/Unit reference Unit title Main evidence source Supplementary evidence source 1 Working safely in an engineering Chapter 1 2, 6, 7, 8, 9, 10, 11, environment 2 Developing yourself and working with other people on engineering activities Chapter 2 Planning, & training records, 1, 4, 11 3 Using and communicating technical Chapter 3, 4 6, 7, 8, 9, 10, 11 information 4 Identifying and selecting engineering Chapter 5 8, 9, 10, materials 5 Marking out for engineering activities Chapter 7 8, Fitting using hand skills Chapter 8, Machining engineering materials Chapters 6, 9, Using computer software packages to assist Chapter 11 4 with engineering activities Application of number assignments Chapter 1, 2 7, 8, 9, 10 Information technology Chapter 11 4 Communications Chapter 2, 4 11 Personal skills: working with others Chapter 2 1, 4, 11 Personal skills: improving own learning and performance Chapter 2 Unit planning training records Problem solving Chapter 12 Incidental evidence throughout Note Evidence for Producing Engineering Drawing using CAD can be generated systematically if Chapter 3 is completed on a CAD system and evidence from Chapter 11 is adopted.

10 Introduction for Candidates This book is designed to help you achieve an NVQ Level 2 in Performing Engineering Operations (PEO) and Key Skills at Level 2. NVQ stands for National Vocational Qualification. Performing Engineering Operations is based on Standards designed by the Engineering Industry Lead Body. The standards which make up the requirements of your award are grouped into Units, and each Unit is subdivided into Elements. Most Units consists of 2 Elements but there may be 3 or more. NVQ2 - PERFORMING ENGINEERING OPERATIONS (PEO) 3 MANDATORY UNITS Divided into at Least 2 ELEMENTS AT LEAST 1 SUPPORT UNIT. OPTIONAL UNITS PLUS PLUS PLUS 6 KEY Skills KEY SKILLS: COMMUNICATIONS, APPLICATIONS OF NUMBER, INFORMATION TECHNOLOGY, PERSONAL SKILLS WORKING WITH OTHERS AND PERSONAL SKILLS IMPROVING OWN LEARNING AND PERFORMANCE PROBLEM SOLVING. The minimum requirement for an NVQ Level 2 award in PEO is 6 Units. However, Advanced Modern Apprentices and Foundation Modern Apprentices need to achieve 8 Engineering Units and Key Skills at Level 2 as shown. AMA s then proceed to NVQ at Level 3. NVQs are evidence-based qualifications. This means that you need to demonstrate that you can do various things as outlined in the Standards and that you understand what you are doing. When you have demonstrated that you can perform a skill to the required standard and that you understand what you are doing, you are signed off. If you fail to perform the skill to the required standard as often happens when you are learning something new then you are given time to practise before you are assessed again. Assessment occurs when you are ready and there may be a number of people who can assess you. Your supervisor will tell you about all

11 xii Introduction for Candidates the people who can act as your assessor. NVQs are not time-based and different trainees may work through the Units at different rates. There are no external exams for the Engineering award. There are external tests for three of the Key Skills.

12 Introduction for Trainers With the pressure on college lecturers and the relative inexperience of some industrial trainers new to this type of work in mind, the book was devised to afford minimum inconvenience in the setting and running of a study programme for engineering trainees. However, it must be recognised that practical skills can only be learned from high quality instruction from suitably qualified teachers who demonstrate the procedures, and who can advise and supervise trainees to ensure that safe practices are observed. Trainees should follow up this instruction with plenty of practice. A qualified assessor should approve each exercise on its completion. When the book is satisfactorily completed a qualification can be applied for. In addition to the mechanical engineering exercises there are opportunities to demonstrate Key Skills and the book includes a number of exercises specially designed to cover the requirements of Key Skills at Level 2. Included at the end of the book are appendices which we hope will be useful throughout a trainee s engineering career. David Salmon and Penny Powdrill 2001

13 1 Working safely in an engineering environment Exercise checklist (Ask your assessor to initial the lower box for each exercise when you have completed it.) Exercise no Initials Date Statutory regulations and organisational requirements Duties and obligations under the Health and Safety at Work Act, 1974 Safety is one of the most important elements in the working life of all people. Mechanical engineers work in an environment which can potentially be very dangerous. Only when dangers are recognised and understood can appropriate measures be taken to protect against personal accidental injury, ill health or damage to equipment. Accidents cost British industry an estimated 4.5 billion each year. Over the years, governments have passed safety laws to ensure that both employers and employees observe health and safety measures whilst at work. The most important of these safety laws is the Health and Safety at Work Act, which was made law in Great Britain in The Health and Safety at Work Act applies to virtually all persons at work in any job. The law places the responsibility for safe working practices onto all of the following parties: Employers. Persons concerned with premises. Persons in control of harmful emissions. Designers, manufacturers and suppliers of goods and materials. Employees and self-employed.

14 2 Working safely in an engineering environment The details of the Health and Safety at Work Act are long and complicated, but the most important sections are Section 2 (General duties of employers to their employees) and Section 7 (General duties of employees at work). The content of these two important sections is explained below. Section 2: General duties of employers to their employees The Act states that It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees. This extends to: Providing and maintaining safe plant and systems of work. All machinery and equipment should be in good working order and be safe. Protective clothing and appropriate safety equipment should be made available free of charge for employees to use. Arranging the safe use, handling, storage and transport of articles and substances. Included in the transport are all cranes, trolleys and appropriate routes to be used. Providing information, instruction, training and supervision to ensure the health and safety of all employees. This includes the provision of safety signs and warnings. Maintaining a safe place of work including both access and exit routes. Buildings and workplaces must comply with the safety standards and correct emergency procedures implemented. Providing and maintaining safe facilities and arrangements for employees welfare at work. For example proper heating, lighting and adequate wash and cloakroom facilities. In addition to the responsibility of the health and safety of his employees, the employer s duties under the Act apply to subcontractors, visitors and the general public whose health and safety may be affected by his activities (e.g. harmful emissions to the atmosphere or hazards in a reception area). There is also a requirement that every employer prepares a written health and safety policy for his employees. This policy should be kept up to date and revised as and when necessary. A safety representative may be appointed and/or elected from amongst the employees. The representative(s) shall represent the employees in consultation with the employers. The consultation between employers and employees should aim to make and maintain arrangements to promote measures to ensure health and safety at work and to check the effectiveness of these measures. A Health and Safety Committee should be set up if requested by the safety representatives, to review all measures taken to ensure health and safety at work and to check the effectiveness of the measures.

15 Working safely in an engineering environment 3 Section 7: General duties of employees at work Employees are also bound by the requirements of the Health and Safety at Work Act. The rules relevant to employees state: It shall be the duty of every employee, whilst at work... to take reasonable care for the health and safety of himself and others who may be affected by his actions or omissions. to co-operate with his employer so far as is necessary, to enable the employer to carry out his duties. This means that all employees (this is you) must: wear suitable protective clothing provided use protective equipment and guards provided maintain their work area in a tidy manner behave sensibly apply safe working practices be familiar with emergency procedures take notice of warning and information signs co-operate with supervisors report all accidents, dangers and incidents. Employees must not work on machinery without instruction and supervision, nor should they interfere with or misuse anything provided to protect the health, safety or welfare of themselves or others. The Health and Safety at Work Act also describes the duties of two bodies, the Health and Safety Commission and the Health and Safety Executive. The Health and Safety Commission assists in the development of health and safety law and promotes health and safety through training, research and publicity. The Health and Safety Executive is concerned with enforcement of the laws. This enforcement is done through inspectors who are employed by local authorities. The inspectors have the power to inspect premises as and when they see fit: any breach of anyone s duties in health and safety laws may result in an improvement notice or a prohibition notice being served on the premises. In some cases criminal prosecutions follow. During your training, there must be a person appointed to supervise you and offer you advice and assistance. Throughout this book, this person is referred to as your supervisor. In the event of your supervisor not being available, another person must be delegated to these duties and you should be aware of who this is. You should also be aware that there is a person appointed to look after safety issues, usually called the Safety Officer. However, for information on safety issues, you would normally refer to your supervisor in the first instance. Your organisation s Safety Officer or the qualified First Aider can be approached if you need specialist advice and/or assistance about health and safety or first-aid issues. There may be a company code of practice for additional rules in your workplace. If you follow the company code of practice and heed any warnings, you will significantly reduce your chances of being involved in an accident. Remember: you are required by law to comply with your company s organisational safety policies and procedures at all times whilst you are at work.

16 4 Working safely in an engineering environment EXERCISE 1.1 State the name and location of the following persons: Name: Where based: Your supervisor: Your first aider: Your safety officer: Write brief comments of your obligations in the following circumstances: 1. You are not sure how to operate a machine required for the task in hand. 2. Your machine guard is broken. 3. You have lost your safety glasses. 4. You need to carry some hot metal parts to a cooling area. 5. The machine you are operating has spilt coolant onto the floor.

17 Working safely in an engineering environment 5 6. Your foreman tells you to clean up a mess that someone else made earlier. 7. You see a colleague struggling to carry a large and bulky load. 8. You see some jobs stacked up in front of the fire exit door. Witness testimony I confirm that...has completed the exercise correctly. Signed...Job title...date... Sources of information relating to regulations on safety procedures Information about health and safety is usually made available to employees by being published on notice boards and posters about the workshops. A health and safety poster must be displayed in places of work to inform employees about the framework of general health and safety duties, safety management and information about safety reps and the responsibilities of the person appointed to deal with health and safety issues. Information about the findings of safety surveys carried out in the workplace would normally be made available to employees through their safety representatives or information on notice boards. Complying with statutory regulations The Health and Safety at Work Act 1974 covers virtually everyone in all kinds of work. There is also legislation relating to specialist engineering processes or situations. If you require safety information about a specific task, it may be useful to refer to one or more of the following acts or regulations: Grinding Metals Special Regulations 1925 & The Factories Act 1961.

18 6 Working safely in an engineering environment Power Press Regulations 1965 & Abrasive Wheel Regulations Eye Shield Regulations Health and Safety (First Aid) Regulations Electricity at Work Regulations COSHH (Control of Substances Hazardous to Health) Regulations 1989 & Manual Handling Operations Regulations Personal Protective Equipment Regulations Provision and Use of Work Equipment Regulations Reporting of Injuries, Diseases and Dangerous Occurrences Regulations First Aid Regulations Management of Health and Safety Regulations Lifting and Operating Lifting Equipment Regulations The above list is far from complete as there are many more laws related to health and safety not listed here. EXERCISE 1.2 State six health and safety requirements in your work area which you must obey: State four health and safety requirements in work areas that you regularly pass through which you must obey: Witness testimony I confirm that...has completed the above exercises correctly. Signed...Job title...date...

19 Working safely in an engineering environment 7 Warning signs and labels of the groups of dangerous substances The warning signs below are designed in accordance with the classification, packaging and labelling of dangerous substances regulations. The square orange box with a black symbol is attached to labels and packaging: it gives information about any hazards related to the contents. The signs are used to mark the main groups of hazardous substances. EXERCISE 1.3 For each of the hazardous substance warning signs below, write an example of a material displaying this warning and state the precautions which are necessary when you come into contact with it. The first one is shown completed for your guidance. Sign: Example: Precautions: Highly flammable Petrol. No smoking or naked flames. Explosive Poison or toxic Oxidising Harmful/ Irritant

20 8 Working safely in an engineering environment Radioactive RADIATION Environmental hazard Corrosive CORROSIVE Witness testimony I confirm that...has completed the above exercise correctly. Signed...Job title...date... Follow accident and emergency procedures Under the Health and Safety (First Aid) Regulations, workplaces must have first-aid provision. In general, this includes a person who is trained as a First Aider, and there must also be at least one adequately stocked first-aid box that is clearly labelled. Note that first-aid boxes are primarily for the use of the registered First Aiders. Most large companies and colleges have a first-aid treatment room. You should know who the First Aider is and where he/she can be found in an emergency. You should also know the location of the first-aid facilities. In the event of an accident, always get the First Aider to the scene of the incident as soon as possible. Where possible stay with the casualty and send someone to get the First Aider. If for any reason the First Aider is not available, dial 999 and ask for an ambulance. However, it is important to know what to do in the event of the First Aider not being immediately available and certainly in the case of electrocution.