Polishing and smoothing of lens or mirror surfaces

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This standard identifies the competences you need to carry out the polishing and smoothing of lenses or mirrors either individually or as a block-mounted group, in accordance with approved procedures. You will be required to use appropriate drawings, specifications and test documentation to set up the equipment and to polish and smooth the lenses or mirrors. You will be expected to use the specified/appropriate techniques to carry out the polishing and smoothing procedures in the correct sequence. The process will include setting up and operating the equipment in line with safe working practices and approved procedures, and to monitor the polishing and smoothing operations, making any necessary adjustments to ensure that the finished lenses or mirrors are to the required quality and accuracy.

Your responsibilities will require you to comply with organisational policy and procedures for the polishing and smoothing activities undertaken, and to report any problems with the activities, components or equipment that you cannot personally resolve, or that are outside your permitted authority, to the relevant people. You will be expected to work 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 provide a good understanding of your work, and will provide an informed approach to the finishing of lenses or mirrors by polishing and smoothing. You will understand the lens or mirror being polished and smoothed and its application. You will know about the polishing and smoothing techniques, procedures, test equipment and methods, in adequate depth to provide a sound basis for carrying out the activities, correcting faults and ensuring that the polishing and smoothing is carried out to the required specification.

You will understand the safety precautions required when carrying out the polishing and smoothing operations. You will be required to demonstrate safe working practices throughout, and will understand the responsibility you owe to yourself and others in the workplace.

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1. work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
2. follow the correct specifications for the component being produced
3. determine what has to be done and how the machine will be set to achieve this
4. mount and set the required workholding devices, workpiece and polishing tools
5. set the machine tool operating parameters to achieve the component specification
6. check that all safety mechanisms are in place and that the equipment is set correctly for the required operations
7. produce polished and smoothed surfaces
8. complete the required production documentation
9. deal promptly and effectively with problems within your control and report those that cannot be solved

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1. how to work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
2. the safety mechanisms on the equipment, and the procedure for checking that they function correctly
3. the importance of wearing protective clothing (PPE) and other appropriate safety equipment during the polishing and smoothing process; the type of equipment to be used, and where to obtain it
4. hazards associated with the lens/mirror polishing and smoothing surface forming process and how to minimise them and reduce any risks
5. the importance of keeping the equipment and work area clean and tidy
6. how to extract and use information from engineering drawings and related specifications (to include symbols and conventions to appropriate standards) in relation to work undertaken
7. how to interpret first and third angle drawings, imperial and metric systems of measurement, workpiece reference points and system of tolerancing
8. how to prepare for the lens/mirror polishing and smoothing activities (such as obtaining the correct workholding jigs, selecting and preparing the various grades of grits, preparing the pitch to hold the lens/mirror)
9. how to mount the lens/mirror ready for the polishing activities
10. how to set up the polishing and smoothing equipment to give the required lens/mirror profile
11. the various quality checks that can be used, and how they are applied during the forming process
12. the surface quality tests to be performed as part of the quality process and to confirm that they are within the specification
13. the problems that can occur with the lens/mirror polishing and smoothing activities, and how they can be overcome
14. how to analyse and evaluate possible characteristics and causes of specific faults/problems
15. how to prepare documentation after completing the surface forming tasks, ready for the next stage
16. the extent of your own responsibility and to whom you should report if you have problems that you cannot resolve

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1. Carry out all of the following during the polishing and smoothing of the lens or mirror surfaces:
   1. obtain and interpret correctly the documentation for the lens or mirror to be polished
   2. adhere to procedures or systems in place for risk assessment, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
   3. ensure that machine guards/safety mechanisms are in place and correctly adjusted at all times
   4. use safe working practices and machine operating procedures at all times
   5. clean down the polishing machines after each stage of polishing, to avoid contamination of differing grit sizes
   6. check that all tools, templates and equipment to be used are within their calibration dates
   7. return all tools and equipment to the correct location on completion of the activities
   8. leave the machine and work area in a safe and clean condition on completion of the polishing and smoothing activities
2. Perform polishing and smoothing for one of the following:
   1. individual lens/mirror forming through grinding, polishing and smoothing
   2. block forming of lenses/mirrors through grinding, polishing and smoothing
3. Prepare and mount the lens/mirror for the polishing and smoothing activities, to include carrying out all of the following:
   1. ensure that any steep radius surfaces have undergone correct machining prior to polishing and smoothing
   2. perform any necessary rough shaping of the lens/mirror surface, if required
   3. prepare the pitch mixture to the correct viscosity, according to the material type to be polished
   4. application and forming of pitch to correct shape
   5. application of a backing pitch and correct runner
   6. cutting of grooves into pitch surface
   7. careful heating of components (such as runner) to ensure correct mounting of the lens/mirror
   8. mounting of lens/mirror into pitch, ensuring correct orientation and position
4. Prepare to carry out the polishing and smoothing activities, to include carrying out all of the following:
   1. select the correct `right curve' or test templates for the lens/mirror to be polished
   2. prepare the series of abrasive grits ready for polishing, ensuring that each is handled correctly to avoid cross contamination
   3. prepare the polishing and smoothing machinery, ensuring its correct and safe operation as well as cleanliness
5. Carry out polishing and smoothing of lenses/mirrors, to include all of the following:
   1. correct mounting of lenses/mirrors onto the polishing machine in the correct orientation
   2. checking that the polishing or smoothing machine is set up correctly to give the required profile
   3. applying the appropriate grit and carrying out the polishing or smoothing process
   4. carrying out appropriate checks to confirm that the profile is correct
   5. adjusting polishing conditions based on the results of checks/tests
   6. cleaning down of the polishing machine between each grit size
   7. carrying out the polishing and smoothing activities with finer grades of grit until the final specification is achieved
   8. preparing the lenses/mirrors for the cleaning process
6. Perform three of the following inspection tests during the polishing process:
   1. Foucault test
   2. radius check
   3. use of test plates to check for correct number of `rings' as per specification
   4. inspecting for surface defects
   5. lens centre thickness
   6. lens cap height
   7. lens surface form error
   8. prism angles
7. Carry out polishing and smoothing of lens/mirror surfaces, in compliance with one of the following:
   1. BS, ISO or EN standards and procedures
   2. customer (contractual) standards and requirements
   3. company standards and procedures
   4. other accepted international standards

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3

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31 Mar 2028

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Current

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Original

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Enginuity

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SEMMME3159

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Engineering, Engineering and Manufacturing Technologies, Engineering Technicians

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3113

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Mechanical engineering; photonics; polishing; smoothing; lens; mirror; surface; Foucault test; radius check; number of rings; surface defects; lens centre thickness; lens cap height; lens surface form error; prism angles

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