Finishing materials by chemical and electro-chemical polishing processes
URN: SEMMPF338
Business Sectors (Suites): Materials Processing and Finishing Suite 3
Developed by: Enginuity
Approved on:
30 Mar 2020
Overview
| This standard identifies the competencies you need to improve surface finishes by chemical and electro-chemical polishing activities, in accordance with approved procedures. You will be required to access the appropriate specifications, to check that these are the current issue and to extract all necessary information in order to carry out the polishing processes. You will be expected to prepare and adjust the processing solutions to give satisfactory results at optimal productivity levels. You will be expected to identify any surface defects and to carry out the necessary actions and adjustments to equipment and solutions in order to correct them. You will need to carry out tests on the components to ensure that the finished substrates meet their specification requirements. Your responsibilities will require you to comply with organisational policy and procedures for the chemical and electro-chemical polishing activities undertaken and to report any problems with these activities or with the materials and equipment used, that you cannot personally resolve, or 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 applying chemical and electro-chemical polishing processes and procedures. You will understand the chemical and electro-chemical polishing process and their application, in adequate depth to provide a sound basis for carrying out the activities, correcting faults, and ensuring the finished components are to the required specification. Your knowledge will also include effluent treatment for the waste streams from the finishing processes and associated pre-treatments. You will understand the safety precautions required when carrying out the chemical and electro-chemical polishing 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 and towards the environment. |
Performance criteria
You must be able to:
| 1. work safely at all times, complying with health and safety legislation, regulations, directives and other relevant guidelines 2. follow relevant job instructions and specifications 3. ensure the material surfaces to be treated are prepared for the finishing operations 4. check that the finishing equipment and treatment solutions are set up and maintained at required operating conditions and levels 5. carry out finishing according to operating procedures and to meet specifications 6. check that the treated workpiece achieves the required characteristics and meets the finishing specification 7. deal promptly and effectively with problems within your control and report those that cannot be solved 8. ensure that work records are completed, stored securely and available to others, as per organisational requirements 9. leave the work area in a safe condition on completion of the activities, as per organisational and legal requirements |
Knowledge and Understanding
You need to know and understand:
| 1. the specific safety precautions to be taken whilst carrying out the activities (including any specific legislation, regulations or codes of practice relating to the activities, equipment or materials) 2. the health and safety requirements of the work area and the activities, and the responsibility these requirements place on you 3. the hazards associated with the activities, and how to minimise them and reduce risks 4. the personal protective equipment and clothing (PPE) to be worn during the activities 5. the importance of an extraction system on certain types of chemical and electro chemical processes, especially where highly toxic fumes can be liberated 6. the importance of keeping the work area clean and tidy including the use of 5S or similar techniques 7. the types of specifications that are used during the polishing activity 8. how to assess component suitability for chemical and electro-chemical polishing (to include methods of handling, methods of pre-treatment, the most efficient and appropriate method of application) 9. how to identify various surface condition specifications, or customer specific requirements and how to advise on the correct process to give the desired results for specific substrates 10. the importance of keeping constituent elements within controlled limits when substrates are formed from alloys (such as aluminium, manganese, zinc castings) to avoid excessive or uneven erosion during the polishing process 11. the non-chromate systems that are available as substitutes for traditional techniques and their importance in reducing health risks and environmental impact 12. the basic principles of operation of the chemical and electro-chemical polishing plant and equipment 13. how to carry out the chemical and electro-chemical polishing operations, and the sequence of operations that are required 14. the advantages and disadvantages of work placement methods, (jigs, baskets, wiring, trays) 15. how to set up and check that the chemical and electro-chemical plant, equipment and solutions are fit for purpose 16. how to control processing times, temperatures and solution concentrations 17. how to make up polishing solutions, and pre-treatment solutions, safely and correctly 18. how to control the level of contaminants in polishing solutions, arising from substrate erosion and how to assess when solutions are ready for replacement 19. how to dispose of spent solutions safely and correctly and clean out process tanks 20. how to carry out effluent treatment 21. the importance of agitation to prevent uneven deposits and temperature layering and the various means of achieving this 22. how to identify and correct chemical and electro-chemical polishing processing faults 23. methods for checking polished surfaces for visual defects and other specified characteristics 24. the extent of your own responsibility and whom you should report to if you have problems that you cannot resolve 25. how to access, use and maintain information to comply with organisational requirements and legislation |
Scope/range
Scope Performance
| 1. Finish materials by chemical and electro-chemical polishing processes, carrying out all of the following activities: 1. use the correct issue of process and other related specifications 2. adhere to health and safety regulations, systems and procedures to realise a safe system of work 3. ensure that the equipment is correctly prepared for the polishing operations 4. ensure that any meters and gauges to be used are within their calibration periods 5. clean all tools and equipment on completion of the polishing activities 6. complete the production documentation (condition/pre-treatment of substrates, coating material preparation, equipment settings, confirmation of standard of finish) 7. leave the work area in a safe and clean condition 2. Carry out chemical or electro-chemical polishing on one of the following substrates: 1. mild steel 2. brass 3. copper 4. stainless steel 5. aluminium 6. other substrate 3. Use one of the following for locating the components during the polishing process: 1. wiring 2. specialised jigs 3. barrels 4. baskets 5. trays 6. other specific device 4. Measure and correct two of the following chemical processing conditions: 1. concentration of constituents in polishing solutions 2. temperature 3. contaminants in polishing solutions 4. pH (acidity/alkalinity) of solutions plus two more from 5. total and free alkalinity of cleaners 6. effectiveness of acid pickling 7. contamination levels in cleaners 8. effectiveness of rinsing 9. temperature of cleaners 5. Carry out two of the following activities: 1. prepare electro and electro-chemical solutions from basic salts 2. dispose of spent solutions safely 3. clean out process tanks correctly 6. Make appropriate corrections for two of the following chemical processing faults: 1. erosion of substrate occurs unevenly 2. reaction occurs too rapidly or too slowly 3. pitting or tearing occurs on substrate surface 4. colour of surface changes due to oxidation 7. Check the processed components for two of the following characteristics: 1. evenness of surface finish 2. colour and brightness 3. surface roughness (visual or quantitative) 4. inclusions in the deposit 8. Use one of the following polishing techniques: 1. acid solutions 2. chromic acid based solutions 3. other chemical or electro-chemical polishing solution (specify) 9. Check finishes applied to components by chemical or electro-chemical polishing comply with one of the following quality and accuracy standards: 1. military or aviation standards 2. current industry standards and codes of practice 3. international standards 4. company standards and requirements 5. customer standards and requirements |
Scope Knowledge
Values
Behaviours
Skills
Glossary
Links To Other NOS
External Links
Version Number
2
Indicative Review Date
31 Mar 2023
Validity
Current
Status
Original
Originating Organisation
SEMTA
Original URN
MPF3.38
Relevant Occupations
Engineering and Manufacturing Technologies, Manufacturing Technologies, Process Operatives, Process, Plant and Machine Operatives
SOC Code
8115
Keywords
Engineering; manufacturing; processing; finishing; chemical; electro-chemical; polishing; parameters; methods