Operating milling machines
Overview
This standard identifies the competences you need to carry out milling operations on a milling machine, 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 expected to produce a range of components that combine a number of different features, such as flat faces, parallel faces, faces that are flat and square to each other, angular faces, steps, slots and special forms.
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 setter to make the required 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 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 actions and for the quality and accuracy of the work that you produce.
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 procedures for milling machining. You will have an understanding of the milling machine process, and its application, and will know about the equipment, materials and consumables in adequate depth to provide a sound background 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:
P1 work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
P2 confirm that the machine is set up and ready for the machining activities to be carried out
P3 operate the machine controls in accordance with safe working practices and operational procedures
P4 produce machined components to the required specification and within the specified dimensional accuracy
P5 carry out quality sampling checks with the appropriate gauges/instruments for accuracy at suitable intervals
P6 deal with problems within your control and report those that cannot be solved
P7 complete and store all relevant documentation in accordance with organisational requirements
P8 shut down the equipment to a safe condition on conclusion of the machining activities
Knowledge and Understanding
You need to know and understand:
K1 how to work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
K2 the safety mechanisms on the machine, and the procedure for checking that they function correctly
K3 operation of the machine controls in both hand and power modes, and how to stop the machine in an emergency
K4 the importance of wearing the appropriate personal protective equipment (PPE), and of keeping the work area clean and tidy
K5 where to obtain the component drawings, specifications and/or job instructions required for the components to be machined
K6 how to extract and use information from engineering drawings and related specifications
K7 how to use imperial and metric systems of measurement
K8 the main features of the milling machine, and the accessories that can be used
K9 the various milling operations that can be performed, and the methods and equipment used
K10 the effects of backlash in machine slides and screws, and how this can be overcome
K11 how to handle and store cutting tools safely and correctly
K12 the application of roughing and finishing cuts, and the effect on tool life, surface finish and dimensional accuracy
K13 the application of cutting fluids with regard to a range of different materials
K14 the effects of clamping the workpiece, and how this can cause distortion in the finished components
K15 how to recognise machining faults, and how to identify when cutters need re-sharpening
K16 the quality control procedures that are used, inspection checks to be carried out, and the equipment that will need to be used
K17 the issues that can occur with the milling activities, and how these can be overcome
K18 the extent of your own responsibility and to whom you should report if you have problems that you cannot resolve
Scope/range
Scope Performance
1. Apply all of the following during the machining activities:
1.1 obtain and use the appropriate documentation (such as job instructions, drawings, quality control documentation)
1.2 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
1.3 confirm with the machine setter that the machine is ready for production
1.4 where appropriate, seek any necessary instruction/training on the operation of the machine
1.5 ensure that machine guards are in place and are correctly adjusted
1.6 hold components securely, without distortion
1.7 follow the defined operating procedures and apply safe working practices and procedures at all times
1.8 ensure that machine settings are adjusted as and when required (either by yourself or the setter) to maintain the required accuracy
1.9 ensure that the components produced meet the required specification for quality and accuracy
1.10 leave the work area and machine in a safe and appropriate condition on completion of the activities
2. Operate one type of milling machine from the following:
2.1 horizontal milling machine
2.2 vertical milling machine
2.3 universal milling machine
3. Produce machined components which combine different operations and cover six of the following:
3.1 flat faces
3.2 open ended slots
3.3 bored holes
3.4 square faces
3.5 enclosed slots
3.6 profile forms (such as vee, concave, convex, gear forms)
3.7 parallel faces
3.8 recesses
3.9 serrations
3.10 angular faces
3.11 tee slots
3.12 indexed or rotated forms
3.13 steps/shoulders
3.14 drilled holes
3.15 special forms
4. Machine components made from one of the following types of material:
4.1 ferrous
4.2 non-ferrous
4.3 non-metallic
5. Use appropriate gauges or instruments to carry out the necessary checks, during production, for accuracy of four of the following:
5.1 dimensions
5.2 angles
5.3 slots
5.4 squareness
5.5 flatness
5.6 recesses
5.7 hole size/fit
5.8 surface finish
6. Produce components with dimensional accuracy, form and surface texture within all the following quality and accuracy standards, as is applicable to the operations performed:
6.1 components to be free from false tool cuts, burrs and sharp edges
6.2 dimensional tolerance as specified in relevant standard
6.3 flatness and squareness within 0.005” per inch or 0.125mm per 25mm
6.4 surface finish 63µin or 1.6µm
6.5 angles within +/- 1 degree