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Operating CNC optical grinding and polishing machines

URN: SEMMME246
Business Sectors (Suites): Mechanical Manufacturing Engineering Suite 2
Developed by: Enginuity
Approved on: 2016

Overview

This standard identifies the competences you need to machine glass and infra-red/special material components, using Computer Numerical Control (CNC) optical grinding and polishing machines, 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 required to produce a range of components of various infra-red and/or visible materials, which combine a range of different features such as surface finish, cap height, diameters, bevels, profiles, parallelism, optical power and form analysis. You will be expected to check and verify the finished components, using a variety of equipment to ensure they meet the required specifications.

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 machine setter to make the 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 CNC optical 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 own actions and for the quality and accuracy of the work that you carry out.

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 CNC optical machining procedures. You will have an understanding of the glass and infra-red/special materials, CNC optical processes and their application, and will know about the equipment, materials and consumables, in adequate depth to provide a sound basis 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 machining equipment is set up and ready for operation
  3. follow the defined procedures for starting and running the operating system
  4. deal promptly and effectively with error messages or equipment faults that are within your control and report those that cannot be solved
  5. produce optical components
  6. check the computer process and ensure that the production output is to the required specification
  7. complete the required production documentation
  8. shut down the equipment to a safe condition on conclusion of the activities

Knowledge and Understanding

You need to know and understand:

  1. the safe working practices and procedures to be followed while operating CNC optical grinding and polishing machines/machining centres
  2. the safety mechanisms on the machine, and the procedure for checking that they function correctly
  3. the operation of the machine controls in both set-up and run modes, and how to stop the machine in an emergency
  4. the personal protective equipment (PPE) to be worn, and where this can be obtained
  5. the hazards associated with carrying out CNC process operations, and how to minimise them and reduce any risks
  6. the importance of keeping the work area clean and tidy
  7. how to extract and use information from optical engineering drawings and related specifications (to include symbols and conventions to appropriate BS, ISO or BSEN standards) in relation to work undertaken
  8. how to use imperial and metric systems of measurement and system of tolerancing
  9. the process methods of CNC optical manufacture, and the use of a variety of grinding and polishing tools (such as diamond abrasive wheels and polishing tools)
  10. the optical component mounting methods used to set up the workpiece prior to operation
  11. how to handle and store all cutting tools and kit required, safely and correctly
  12. the factors that affect the selection of cutting feeds, pressures and speeds and the depth of cut
  13. how tool wear affects surface finish and dimensional accuracy
  14. how the various types of material will affect the way the operation is performed
  15. the application of cutting fluids with regard to the range of material being produced
  16. how to recognise machine faults, and how to identify when grinding wheels need refurbishment
  17. the problems that can occur with optical grinding and polishing machines, and how they can be overcome
  18. the quality control procedures used, inspection checks to be carried out, and the equipment used
  19. the extent of your own responsibility and to whom you should report if you have problems that you cannot resolve

Scope/range

Scope Performance

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  1. Apply all of the following during the machine 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 damage or distortion
    7. maintain the cutting tools in a suitable condition
    8. ensure that the operating program is at the correct start point before starting the machine
    9. ensure that the workpiece is clear of the machine spindle
    10. ensure that safe working practices and start-up procedures are observed
    11. ensure that machine settings are adjusted as and when required (either by yourself or the setter) to maintain the required accuracy
    12. ensure that the components produced meet the required specification for quality and accuracy
    13. leave the work area and machine in a safe and appropriate condition on completion of the activities

  2. Operate one of the following CNC optical process machines:

    1. CNC 3 axis machine   
    2. CNC generating machine
    3. CNC optical edging machine
    4. CNC 4 axis machine  
    5. CNC smoothing machine
    6. CNC optical grinding machine
    7. CNC polishing machine   
    8. CNC special purpose machines
    9. other CNC processing machines

  3. Produce optical machined components which combine different operations and cover four of the following:

    1. centre thickness
    2. bevels      
    3. optical form analysis
    4. surface finish   
    5. component profile
    6. optical power (radius of curvature)
    7. cap height   
    8. concentricity 
    9. diameter/step feature, angles

  4. Machine three different types of materials from the following:

    1. germanium
    2. silicon 
    3. zinc selenide
    4. zinc sulphide
    5. lanthanum crowns 
    6. dense flints 
    7. flints/light flints
    8. barium crowns      
    9. borosilicate crowns  
    10. barium dense flints
    11. anomalous dispersion flour crowns
    12. other appropriate optical material

  5. Carry out the necessary checks for accuracy, during production, of four of the following:

    1. centre thickness 
    2. component surface finish
    3. component cosmetic defects
    4. component profiles
    5. bevels/chamfers    
    6. lens diameter
    7. surface power error     
    8. surface form error      
    9. angles        
    10. cap height

  6. Produce components with dimensional accuracy, form and surface quality, which complies to one of the following standards applicable to the operations:

    1. BS, ISO or BSEN standards and procedures
    2. customer (contractual) standards and requirements
    3. company standards and procedures
    4. other accepted international standards

Scope Knowledge

Values

Behaviours

Skills

Glossary

Links To Other NOS

External Links

Version Number

2

Indicative Review Date

2019

Validity

Current

Status

Original

Originating Organisation

Semta

Original URN

SEMMME2-46

Relevant Occupations

Engineering, Engineering and Manufacturing Technologies, Engineering Technicians

SOC Code

5221

Keywords

engineering; manufacturing; mechanical; machining; optical; CNC grinder; CNC polisher; CNC edging machine; lens smoothing; lens profiling; operating