Machining components using milling machines
Overview
This standard identifies the competences you need to carry out milling operations, in accordance with approved procedures, using machines such as horizontal, vertical, universal, planer milling machines and boring machines with milling attachments. You will be required to check 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 components that combine a number of different features, such as flat faces, parallel faces, faces that are square to each other, angular faces, steps and slots, drilled and bored holes, and special forms.
You will be required to operate the machine in line with safe working practices and approved procedures, and to continuously monitor the machining operations, making any necessary 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 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 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 machining procedures. You will understand the milling process, and its 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 and 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.
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
- manipulate 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
- deal promptly and effectively with problems within your control and report those that cannot be solved
- complete the required production documentation
- 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 machine, and the procedure for checking that they function correctly
- operation of the machine controls in both hand and power 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 carrying out the milling operations, and how to minimise them and reduce any risk
- the importance of keeping the work area clean and tidy
- where to obtain the component drawings, specifications and/or job instructions required for the components to be machined
- 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 application of a range of milling machines
- the various milling techniques that can be used to produce the required shapes, and the types of milling cutters required
- conventional and climb milling techniques, and when each method should be used
- the methods that can be used to position the workpiece in relation to the milling cutters
- the effects of backlash in machine slides and screws, and how this can be overcome
- how to handle and store cutting tools safely and correctly
- factors which affect the selection of cutting feeds and speeds, and the depth of cut that can be taken
- how the various types of material will affect the feeds and speeds that can be used
- the application of roughing and finishing cuts, and the effect on tool life, surface finish and dimensional accuracy
- the application of cutting fluids with regard to a range of different materials
- the effects of clamping the workpiece, and how this can cause distortion in the finished components
- the effects of removing material, how this can cause warping/distortion of the workpiece, and how this can be overcome
- how to recognise machining faults and identify when cutters need re-sharpening
- the quality control procedures used, inspection checks to be carried out, and the equipment to be used
- the problems that can occur with the milling activities, and how these can be overcome
- the extent of your own authority and to whom you should report if you have problems that you cannot resolve
Scope/range
Scope Performance
- Ensure that you apply all of the following during the machining activities:
- obtain and use the appropriate documentation
- 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 are in place and correctly adjusted
- hold components securely without distortion
- maintain cutting tools in a suitable condition
- apply safe working practices at all times
- adjust machine settings, as required, to maintain the required accuracy
- ensure that components produced meet specification
- leave the work area and machine in a safe and appropriate condition on completion of the activities
- Manipulate one type of milling machine from the following:
- horizontal milling machine
- vertical milling machine
- universal milling machine
- planer/gantry milling machine
- boring machines with milling attachments
- Produce machined components which combine different operations and cover eight of the following:
- flat faces
- open ended slots
- profile forms
- square faces
- enclosed slots/recesses
- serrations
- parallel faces
- tee slots
- indexed or rotated forms
- angular faces
- drilled holes
- special forms
- steps/shoulders
- bored holes
- Machine components made from one type of material from the following:
- ferrous
- non-ferrous
- non-metallic
- Carry out the quality sampling checks during production for accuracy of five of the following:
- dimensions
- hole size/fit
- angles
- slots
- squareness
- surface finish
- flatness
- recesses
- Produce components within all of the relevant quality and accuracy standards as applicable to the operations performed:
- components to be free from false tool cuts, burrs and sharp edges
- general dimensional tolerance +/- 0.15mm or +/- 0.006"
- one or more specific dimensional tolerances within +/- 0.05mm or +/- 0.002"
- flatness and squareness within 0.001" per inch or 0.025mm per 25mm
- surface finish 63µin or 1.6µm
- angles within +/- 0.5 degree
- bored holes within H8