Machining components using gear grinding machines
Overview
This standard identifies the competences you need to carry out gear grinding operations, in accordance with approved procedures. You will be required to check that the machine is ready for the operations to be performed, and that all the required components, consumables and gear measuring equipment is available. You will be expected to grind a range of gears, such as spur gears, helical and double helical gears, bevel gears, and splines.
You must operate the machine in line with safe working practices and approved procedures, and 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 grinding activities undertaken, and to report any problems with the grinding activities that you cannot resolve, or are outside your permitted authority, to the relevant people. You will be expected to work with minimum 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 gear grinding procedures. You will understand the gear grinding process undertaken, 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.
This standard does not cover CNC applications, for which other standards apply.
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
- your duties and responsibilities under the abrasive wheels regulations, with particular reference to the mounting of abrasive wheels
- 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 gear grinding operations, and how to minimise them and reduce any risks
- 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
- terminology used in gear grinding in relation to the activities undertaken
- the various gear grinding operations that are used to produce the required gear forms, and the types of grinding wheels used
- how to dress and reshape single and multi-ribbed grinding wheels, and the equipment to be used
- the methods that can be used to position the gear in relation to the grinding wheel
- the importance of checking the gear concentricity before grinding, and tools and equipment that are used
- the effects of backlash in machine slides and screws, and how this can be overcome
- how to handle and store grinding wheels safely and correctly
- factors which affect the selection of grinding wheel feeds and speeds, and the depth of cut that can be taken
- the application of roughing and finishing cuts, and the effect on wheel life, surface finish and dimensional accuracy
- the reason for using cutting fluids, and the type of fluid used
- the effects of clamping the workpiece, and how this can cause distortion in the finished components
- how to recognise grinding faults and identify when grinding wheels need re-dressing/forming
- the quality control procedures used, inspection checks to be carried out, and the equipment to be used
- the problems that can occur with the gear grinding 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
1. 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 grinding wheels in a safe and usable 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
2. Operate one of the following types of gear grinding machine:
- gear grinding using formed wheels
- gear grinding by generation
3. Finish grind two of the following types of gears applicable to the machine type:
- external spur gear
- bevel gears
- internal spur gear
- straight splines
- single helical gear
- involute splines
- double helical gear
- tip and root relief
4. Grind gears made from one of the following types of material:
- ferrous
- non-ferrous
- non-metallic
5. Carry out the necessary checks during production for accuracy of four of the following:
- gear tooth profile
- lead and pitch
- gear tooth thickness
- involute form
- concentricity
- surface texture
6. Produce components within all the relevant quality and accuracy standards, as applicable to the operations performed:
- dimensional tolerance equivalent to relevant standard
- surface texture 8 µin or 0.2µm
- components to be free from false grinding cuts, burrs and sharp edges