Machining optical prism and flat components
Overview
This standard identifies the competences you need to carry out machining operations on optical prisms and flat components, using a range of optical prism and flat process machines, in accordance with approved procedures. You will be required to set up the machine for the operations to be performed, and to check that all the required components or materials and consumables are available. In operating the machine, you will be expected to produce a range of components that combine a number of different features, such as angles, flats, parallelism, wedge shapes, chamfers and bevels, using a selection of specified optical prism and flat materials. You will also be required to check finished components that have been machined by the combination of various processes, for accuracy and quality.
You will be required to set up and operate the machine in line with safe working practices and approved procedures and to continuously monitor the machining operations, making any necessary adjustments to settings 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 optical machining activities undertaken, and to report any problems with the optical machining activities, materials, tooling or consumables that you cannot personally resolve, 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 produce.
Your underpinning knowledge will provide a good understanding of your work, and will provide an informed approach to applying optical machining procedures. You will understand the optical prism and flat machining 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 machines and with their 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.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
- confirm that the machine is set up and ready for the machining activities to be carried out
- operate the machine tool controls safely and correctly, in line with operational procedures
- produce components to the required quality and within the specified dimensional accuracy
- carry out quality sampling checks at suitable intervals
- complete production documentation
- deal promptly and effectively with problems within your control and report those that cannot be solved
- shut down the equipment to a safe condition on conclusion of the machining activities
Knowledge and Understanding
You need to know and understand:
- how to work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
- the safety mechanisms on the machines, and the procedure for checking that they function correctly
- the operation of the machine controls in both set-up and run modes, and how to stop the machine in an emergency
- the personal protective equipment (PPE) to be worn, and where this can be obtained
- the hazards associated with optical prism process operations, and how to minimise them and reduce any risks
- the importance of keeping the work area clean and tidy
- 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
- how to interpret first and third angle drawings, imperial and metric systems of measurement, workpiece reference points and system of tolerancing
- the various optical prism operations that can be performed, and the shapes and types of tooling that can be used
- the methods that can be used to set up the workpiece, prior to the operation, to minimise optical wedge and parallelism in relation to the cutting tool
- how to handle and store all tools and kit required, safely and correctly
- factors which affect the selection of cutting feeds, pressures and speeds required
- how tool wear affects surface finish and dimensional accuracy
- how the various types of material will affect the way the operation is performed
- the application of cutting fluids with regard to the range of materials being machined
- the effect of clamping the workpiece, and how this can cause distortion in the finished component
- the problems that can occur with optical prism machining activities, and how they can be overcome
- the quality controls procedures used, inspection checks to be carried out, and the equipment used to achieve the required components
- 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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- Carry out all of the following during the optical prism machining activities:
- obtain and interpret correctly the documentation for the type of lens being machined
- 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
- ensure that machine guards/safety mechanisms are in place and correctly adjusted at all times
- ensure that components are correctly positioned and held securely, without damage or distortion
- ensure that tooling is appropriate for the operations and is maintained in a suitable condition
- set the tooling and machine operating parameters to achieve the component specification
- adjust machine settings, as required, during the machining activities to maintain component accuracy
- use safe working practices and machine operating procedures at all times
- leave the machine and work area in a safe and clean condition on completion of the machining activities
- Operate four of the following types of optical prism and flat process machines:
- preparation and smoothing
- twin lap flat polishing
- lap-master flat and prism
- hard lap flat and prism polishing
- roof prism process (accurate angles)
- Produce machined optical components which combine different operations, and cover six of the following:
- flat centre thickness
- angular tolerances
- flatness tolerances
- parallelism tolerances
- cosmetic tolerances
- transmission tolerances
- finished size tolerances
- prism chamfers/bevels tolerances
- Machine four different types of material from the following:
- optical grade germanium
- zinc selenide prisms and flats
- zinc sulphide prisms and flats
- borosilicate crowns
- barium crowns
- dense flints
- optical orange filter glass
- optical neutral density glass
- barium dense flints
- optical blue filter glass
- flint/light flints
- lanthanum crowns
- anomalous dispersion flour crowns
- other specific optical material
- During production, carry out the necessary checks for optical accuracy, to include five of the following:
- flatness
- prism chamfers and bevels
- transmission deviation measurement
- flat centre thickness
- prism surface cosmetics
- prism flatness measurement
- flat surface cosmetics
- flat chamfers and bevels
- prism angular measurement
- flat parallelism
- prism balk height measurement
- flatness transmission
- Produce components with dimensional accuracy, form and surface quality, in compliance with one of the following:
- BS, ISO or EN standards and procedures
- customer (contractual) standards and requirements
- company standards and procedures
- other accepted international standards