Producing aircraft components by manual machining
Overview
This standard identifies the competences you need to produce aircraft components using manual machining techniques, such as milling, turning, grinding, shaping/slotting, drilling/boring and spark/wire erosion, in accordance with approved procedures. It covers both fixed wing and rotary winged aircraft components. You will be expected to produce aircraft components that require you to use a range of different machines and this will involve setting up the workholding arrangements, workpiece and machine tooling. The workpieces produced will have a combination of features, such as diameters, lengths, threads, flat faces, square faces, slots, profiles or special forms.
Your responsibilities will require you to comply with organisational policy and procedures for the machining activities undertaken and to report any problems with the machines, tooling, materials or activities that you cannot personally resolve, or are outside your personal responsibilities, 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 machining procedures and instructions in an aeronautical manufacturing environment. You will understand the machining processes and their application and will know about the machine, tooling, ancillary equipment, materials and consumables, in adequate depth to provide a sound basis for carrying out the machining activities, correcting faults and producing the components to the required aircraft specification.
You will understand the safety precautions required when working with the machines and 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.
This standard does not cover using computer numerically controlled CNC equipment, for which other standards apply.
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
- 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
- leave the work area and machine in a safe and appropriate condition on completion of the activities
Knowledge and Understanding
You need to know and understand:
- the safe working practices and procedures to be followed while operating machinery
- the requirements and importance of understanding and applying human factors as defined by the regulatory requirements and the potential impact if these are not adhered to
- the safety mechanisms on the machine and the procedure for checking that they are operating correctly
- how to operate all the machine controls in both hand and power modes and how to stop the machine in case of an emergency
- the importance of wearing appropriate protective clothing and equipment (PPE) and of keeping the work area clean and tidy
- the hazards associated with carrying out machining operations and how to minimise them and reduce any risks
- 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 CAA, FAA, BS, ISO or BSEN 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 concepts of material removal using machines (such as lathes, milling, grinding, drilling, shaping, slotting and electro-discharge machining)
- the various machining techniques that can be used to produce the required shapes and the types of tooling and cutters required (such as high-speed steel tools, solid carbide tools and interchangeable tipped tooling)
- types and applications of grinding wheels; methods of mounting; and why some wheels require balancing
- types and application of electrodes used in spark erosion activities
- the methods that can be used to position the workpiece in relation to the cutting tools
- the effects of backlash in the machine slides and how this can be overcome
- how to handle and store cutters, grinding wheels and tools, safely and correctly
- factors which effect the selection of cutting feeds and speeds, the application of roughing and finishing cuts and the depth of cut that can be taken (such as workpiece rigidity, machine condition, type of tooling being used, material type, finish and tolerance required)
- how the various types of material will affect the feeds and speeds that can be used
- the application of cutting fluids and dielectrics with regard to a range of different materials
- the effects of clamping the workpiece and how material removal can cause warping/distortion in the finished workpiece
- the quality control procedures used, inspection checks to be carried out and the equipment to be used
- the problems that can occur with the machining activities and how these can be overcome
- the extent of your own responsibility and to whom you should report if you have problems that you cannot resolve
Scope/range
Scope Performance
Carry out all of the following during the machining activities:
- obtain and use the appropriate documentation (such as job instructions, drawings, quality control documentation)
- adhere to procedures or systems in place for risk assessment, COSHH, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
- ensure that machine guards and safety devices are in place and correctly adjusted
- hold components securely without distortion
- maintain cutting tools in a safe and usable condition
- apply safe working practices and appropriate machining techniques at all times
- ensure that components produced meet specification
Produce machined aircraft components using three of the following machining processes:
- turning
- milling
- grinding
- drilling
- electro-discharge machining
- shaping or slotting
Use a range of workholding devices, to include five of the following:
- three jaw chucks
- clamping arrangements
- face plates
- four jaw chucks
- angle plates
- special fixtures
- machine vices
- magnetic plates
- collet chucks
- vee blocks
- indexing devices
- other specific workholding device
Produce machined aircraft components which cover seven of the following features:
- external diameters
- threads
- slots/recesses
- internal diameters
- circular/curved/radial profiles
- drilled/bored/reamed holes
- lengths/depths
- faces that are square to each other
- concave or convex forms
- flat faces
- angular/tapered surfaces
- special forms
- parallel faces
- steps/shoulders
- other specific feature
Machine three different types of material from:
- low carbon steel
- stainless steel
- aluminium
- plastic/synthetic
- brass
- high carbon steel
- cast iron
- composite
- special steels or alloys
- bronze
Carry out the necessary checks during machining, for accuracy of five of the following:
- dimensions
- flatness/squareness
- thread size and fit
- profile
- angles
- concentricity
- hole size/fit
- quality of surface finish
Produce aircraft components within all of the following standards, as applicable to the operation performed:
- dimensional tolerance equivalent to BS EN ISO 286-1 or BS 1916-1 Grade 7
- flatness and squareness 0.001″ per inch or 0.025mm per 25mm
- reamed and bored holes within H8
- surface finish 63 µin or 1.6 µm
Machine aircraft components which comply with one of the following standards:
- Civil Aviation Authority (CAA)/European Aviation Safety Agency (EASA)
- Ministry of Defence (MoD)
- Military Aviation Authority (MAA)
- Federal Aviation Authority (FAA)
- Aerospace Quality Management Standards (AS)
- BS, ISO or BSEN standards and procedures
- customer standards and requirements
- company standards and procedures
- manufacturers standards and procedures
Complete the relevant paperwork, to include one from the following and pass it to the appropriate people:
- build records
- job cards
- log cards
- aircraft log
- other specific recording method
Scope Knowledge
Values
Behaviours
You will be able to apply the appropriate behaviours required in the workplace to meet the job profile and overall company objectives, such as:
- strong work ethic
- positive attitude
- team player
- dependability
- responsibility
- honesty
- integrity
- motivation
- commitment