Using grinding machines
Overview
This standard covers a range of basic grinding competences that will prepare you for entry into the engineering or manufacturing sectors, creating a progression between education and employment, or that will provide a basis for the development of additional skills and occupational competences in the working environment.
The grinding operations may be carried out on horizontal or vertical surface grinding machines, cylindrical or universal grinding machines. You will be expected to prepare for the grinding activities by obtaining all the necessary job instructions, materials, tools, equipment and any documentation that may be required.
In grinding the workpieces, you will be required to work to instructions, to mount, position and set the workpiece, and to use grinding feeds, speeds and techniques appropriate to the type of material, type of grinding wheel and operations performed. You will be expected to grind components that combine a number of different features, such as flat faces, parallel faces, faces square to each other, angular faces, steps and slots, or parallel, stepped and tapered diameters, faces, bores and special forms/profiles.
During, and on completion of, the grinding operations, you will be expected to check the quality of your work, using measuring equipment appropriate to the aspects being checked and the tolerances to be achieved. You will need to be able to recognise grinding defects, to take appropriate action to put right any faults that occur, and to ensure that the finished workpiece is within the drawing requirements. On completion of the grinding activities, you will be expected to leave the machine and work area in a safe and tidy condition.
Your responsibilities will require you to comply with health and safety requirements and organisational policy and procedures for the grinding activities undertaken. You will need to report any difficulties or problems that may arise, and to carry out any agreed actions. You will work under a high level of supervision, whilst taking responsibility for your own actions and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide an understanding of your work, and will enable you to apply appropriate grinding techniques safely. You will understand the grinding process, and its application, and will know about the equipment, materials and consumables, to the required 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 grinding machine, and with 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.
Specific Standard Requirements
At least one of the components produced must combine different features and techniques, for example: by producing a component which involves grinding stepped diameters or grinding flat parallel or square faces.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety legislation, regulations, directives and other relevant guidelines
- obtain and prepare the appropriate materials, tools and equipment
- mount the workpiece safely and securely, in line with instructions
- set and adjust the machine tool speeds and feeds, in line with instructions (where appropriate)
- use the machine tool controls safely and correctly, in line with operational procedures
- produce ground machined components
- check that the finished components meet the standard required
- report any difficulties or problems that may arise with the grinding activities, and carry out any agreed actions
- shut down the equipment to a safe condition on completion of the grinding activities
Knowledge and Understanding
You need to know and understand:
- the safe working practices and procedures to be followed when preparing and using grinding machines (such as ensuring the correct isolation of the machine before mounting the workholding devices and workpiece; fitting and adjusting machine guards and dust extraction equipment, ensuring that the workpiece is secure, and that grinding wheels are free from damage and are clear of the workpiece before starting the machine)
- the hazards associated with the grinding operations (such as revolving/moving parts of machinery, sparks/airborne particles, bursting grinding wheels, insecure components, burrs and sharp edges on components), and how they can be minimised
- the personal protective equipment (PPE) to be worn for the grinding activities (such as correctly fitting overalls and safety glasses; ensuring that, if you have long hair, it is tied back or netted; and removing any jewellery or other items that can become entangled in the machinery)
- the safety mechanisms on the machine, and the procedure for checking that they function correctly
- the correct operation of the machine controls in both hand and power modes; how to stop the machine in both normal and emergency situations, and the procedure for restarting after an emergency
- the importance of keeping the work area clean and tidy (such as cleaning the machine, disposal of waste, ensuring any spilt cutting fluids are correctly dealt with)
- how to use and extract information from engineering drawings and related specifications (to include BS or ISO standard symbols and abbreviations, imperial and metric systems of measurement, workpiece reference points and system of tolerancing)
- how to mount the workpiece in the workholding devices (such as magnetic chucks and blocks, vices, angle plates, fixtures, centres, mandrels, collets and chucks)
- the effects of clamping the workpiece in a chuck/work holding device, and how this can cause damage or distortion in the finished components
- how to check that the grinding wheels are in a safe and serviceable condition (such as free from damage, cracks, correctly balanced)
- the need for `trueing up' and dressing of wheels to prevent glazing and burning of the workpiece, and methods of forming the wheels to the required profile (such as use of pantograph, diamond dressing units)
- the effects of backlash in machine slides and screws, and how this can be overcome
- the techniques of taking trial cuts and checking dimensional accuracy
- the application of roughing and finishing cuts, and the effect on tool life, surface finish and dimensional accuracy
- the types of grinding wheels, cutting feeds and speeds to be used, and the depth of cut that can be taken
- the application of cutting fluids with regard to a range of different materials, and why some materials do not require cutting fluids to be used
- how to recognise grinding faults, and how to identify when grinding wheels need dressing
- the checks to be carried out on the components before removing them from the machine (such as have all operations been completed, dimensional checks, surface finish checks)
- the problems that can occur with the grinding activities (such as defects caused by glazed wheels, inappropriate feeds/speeds, damage by workholding devices), and how these can be overcome
- when to act on your own initiative and when to seek help and advice from others
- the importance of leaving the machine in a safe condition on completion of activities (such as correctly isolated, cleaning the machine, and removing and disposing of waste)
Scope/range
Scope Performance
Ensure that you apply all of the following checks and practices at all times during the grinding activities:
- adhere to procedures or systems in place for risk assessment, COSHH, personal protective equipment (PPE) and other relevant safety regulations
- ensure that machine guards are in place and are correctly adjusted
- ensure that components are held securely (without damage or distortion)
- ensure that grinding wheels are maintained in a suitable/safe condition
- apply safe and appropriate grinding techniques and procedures at all times
- ensure that the work area is maintained and left in a safe and tidy condition
Grind components made from one of the following types of material
- low carbon/mild steel
- cast iron
- plastic/nylon/composite
- high carbon steel
- brass/brass alloys
- aluminium/aluminium alloys
- other specific material
Grind components mounted on one of the following workholding devices:
- magnetic chuck or blocks
- angle plates
- chucks
- fixed vice
- vee block and clamps
- centres
- swivel or universal vice
- fixtures
- mandrels
Prepare grinding wheels, to include carrying out one of the following:
- dressing and `trueing up' grinding wheels
- wheel forming (such as chamfers, radii, angular forms, profiles)
- relieving the wheel sides
Grind components which combine different operations and have features that cover three of the following:
- flat faces
- steps and shoulders
- counterbores
- parallel faces
- slots
- tapered bores
- faces square to each other
- parallel diameters
- parallel bores
- vertical faces
- stepped diameters
- profile forms
- angular faces
- tapered diameters
Carry out checks for accuracy, to include all of the following:
- dimensions
- parallelism
- surface texture
Use all of the following measuring equipment during the grinding and checking activities:
- external micrometers
- surface finish equipment (such as comparison plates, machines)
Produce components to all of the following quality and accuracy standards, as applicable to the operation:
- components to be free from false grinding cuts, wheel marks, burrs and sharp edges
- general dimensional tolerance +/- 0.1mm or +/- 0.004"
- flatness and squareness within 0.025mm per 25mm or 0.001" per inch
- surface texture 16 µin or 0.4µm
Scope Knowledge
Values
Behaviours
Additional Information
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