Operating electro-discharge machines

URN: SEMMME213
Business Sectors (Suites): Mechanical Manufacturing Engineering Suite 2
Developed by: Enginuity
Approved on: 29 Feb 2016

Overview

This standard identifies the competences you need to carry out machining operations on an electro-discharge machine, in accordance with approved procedures. You will confirm with the machine setter that the machine is ready for the operations to be performed and that all the required components/materials and consumables are available. You will be expected to produce a range of component shapes, such as internal and external profiles that have flat, square, parallel and tapered faces, square /rectangular forms, concave and convex forms, holes, slots, radii/arcs, cavities and special forms.

You will be required to operate the machine in line with safe working practices and approved procedures, to continuously monitor the machining operations and, where necessary, make minor adjustments or seek the help of the setter to make the required adjustments, in order to ensure that the work output is to the required quality and accuracy. Meeting production targets will be an important issue, and your production records must show consistent and satisfactory performance.

Your responsibilities will require you to comply with organisational policy and procedures for the machining activities undertaken, and to report any problems with the machining activities that you cannot personally resolve, or are outside your permitted authority, to the relevant people. You will be expected to work to instructions, with a minimum of supervision, taking personal responsibility for your actions and for the quality and accuracy of the work that you produce.

Your underpinning knowledge will be sufficient to provide a sound basis for your work, and will enable you to adopt an informed approach to applying procedures for electro-discharge machining. You will have an understanding of the electro-discharge process and its application, and will know about the equipment, materials and consumables in adequate depth to provide a sound background for carrying out the activities to the required specification.

You will understand the safety precautions required when working with the machine, its associated tools and equipment. You will be required to demonstrate safe working practices throughout, and will understand the responsibility you owe to yourself and others in the workplace.

Setting up of the machine, its tooling and associated workholding devices, is the subject of another standard and is the responsibility of the machine-tool setter.


Performance criteria

You must be able to:

  1. work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
  2. confirm that the machine is set up and ready for the machining activities to be carried out
  3. operate the machine tool controls safely and correctly in line with operational procedures
  4. produce components to the required quality and within the specified dimensional accuracy
  5. carry out quality sampling checks at suitable intervals
  6. deal promptly and effectively with problems within your control and report those that cannot be solved
  7. complete the required production documentation
  8. shut down the equipment to a safe condition on conclusion of the machining activities

Knowledge and Understanding

You need to know and understand:

  1. the safe working practices and procedures to be followed whilst operating electro-discharge machines
  2. the hazards associated with the operating electro-discharge machines and carrying out the machining operations (such as moving machine parts, electrical components, handling dielectrics, fumes), and how to minimise them and reduce any risks
  3. the safety mechanisms on the machine, and the procedure for checking that they function correctly
  4. operation of the machine controls in both hand and power modes (including rapid power, where appropriate)
  5. how to stop the machine in both normal and emergency situations, and the procedure for restarting after an emergency
  6. the personal protective equipment (PPE) to be worn, and where this can be obtained
  7. the importance of keeping the work area clean and tidy
  8. where to obtain the component drawings, specifications and/or job instructions required for the components to be machined
  9. how to extract and use information from engineering drawings and related specifications (to include symbols and conventions to appropriate BS, ISO or BSEN standards) in relation to work undertaken
  10. how to use imperial and metric systems of measurement
  11. the main features of the electro-discharge machine being used, and the accessories that can be used
  12. the various erosion operations that can be performed, and the methods and equipment used
  13. how to handle and store electrodes and wires safely and correctly
  14. the application of roughing and finishing cuts, and the effect on electrode life, surface finish and dimensional accuracy
  15. the application of dielectric fluid with regard to a range of different materials
  16. the effects of clamping the workpiece in a chuck/workholding device, and how this can cause distortion in the finished components
  17. how to recognise machining faults, and how to identify when electrodes need changing
  18. the quality control procedures used, inspection checks to be carried out, and the equipment that will need to be used
  19. the problems that can occur with the electro-discharge machining activities, and how these can be overcome
  20. the extent of your own authority and to whom you should report if you have problems that you cannot resolve

Scope/range


Scope Performance

1.         Apply all of the following during the machining activities:

    1. obtain and use the appropriate documentation (such as job instructions, drawings, quality control documentation)
    2. adhere to procedures or systems in place for risk assessment, COSHH, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
    3. confirm with the machine setter that the machine is ready for production
    4. where appropriate, seek any necessary instruction/training on the operation of the machine
    5. ensure that machine guards are in place and are correctly adjusted
    6. hold components securely, without distortion
    7. follow the defined operating procedures and apply safe working practices and procedures at all times
    8. ensure that machine settings are adjusted as and when required (either by yourself or the setter) to maintain the required accuracy
    9. ensure that the components produced meet the required specification for quality and accuracy
    10. leave the work area and machine in a safe and appropriate condition on completion of the activities

       

2.         Operate one of the following types of electro-discharge machine:

    1. spark erosion 
    2. wire erosion

       

3.         Produce machined components which include four of the following features:

    1. flat faces   
    2. concave forms
    3. profile forms  
    4. square/rectangular forms
    5. square faces     
    6. convex forms    
    7. cavities         
    8. angular faces
    9. parallel faces     
    10. holes       
    11. radii/arcs    
    12. threads            
    13. engraving 
    14. slots
    15. other special features

       

       

4.         Machine components made from one of the following types of material:

    1. ferrous
    2. non-ferrous

       

5.         Use appropriate gauges or instruments to carry out the necessary checks, during production, for accuracy of three of the following:

    1. dimensions          
    2. surface texture
    3. parallelism           
    4. profile
    5. angle/taper
    6. squareness

 

6.         Produce components with dimensional accuracy, form and surface texture within all the relevant quality and accuracy standards as is applicable to the operations performed:

    1. components to be free from false starts and sharp edges
    2. tolerance to BS EN 20286 or BS 1916 Grade 9
    3. surface texture 32µin or 0.8µm or 18VDI


Scope Knowledge


Values


Behaviours


Skills


Glossary


Links To Other NOS


External Links


Version Number

2

Indicative Review Date

31 Mar 2019

Validity

Current

Status

Original

Originating Organisation

Semta

Original URN

SEMMME2-13

Relevant Occupations

Engineering, Engineering and Manufacturing Technologies, Engineering Technicians

SOC Code

5221

Keywords

engineering; manufacturing; mechanical; machining; operating; electro-discharge machine; spark erosion; wire erosion; convex forms; concave forms