A grinding wheel is a wheel composed of an abrasive compound and used for various grinding (abrasive cutting) and abrasive machining operations. Such wheels are used in grinding machines.
The wheels are generally made from a composite material consisting of coarse-particle aggregate pressed and bonded together by a cementing matrix (called the bond in grinding wheel terminology) to form a solid, circular shape. Various profiles and cross sections are available depending on the intended usage for the wheel. They may also be made from a solid steel or aluminium disc with particles bonded to the surface. Today most grinding wheels are artificial composites made with artificial aggregates, but the history of grinding wheels began with natural composite stones, such as those used for millstones.
The manufacture of these wheels is a precise and tightly controlled process, due not only to the inherent safety risks of a spinning disc, but also the composition and uniformity required to prevent that disc from exploding due to the high stresses produced on rotation.
Grinding wheels are consumables, although the life span can vary widely depending on the use case, from less than a day to many years. As the wheel cuts, it periodically releases individual grains of abrasive, typically because they grow dull and the increased drag pulls them out of the bond. Fresh grains are exposed in this wear process, which begin the next cycle. The rate of wear in this process is usually very predictable for a given application, and is necessary for good performance.
Risk Associated with the Use of Abrasive Wheel
There are many potential hazards surrounding the use of abrasive wheels. However, the ones relevant to your situation will be dependent on the type of equipment that you’re operating, your working environment and the material you’re working with.
- Touching the Wheel
An accidental touch of the wheel can cause the operator serious damage, and this is down to the power of the machine. Tools which are designed to cut and grind will cause significant damage if they come into contact with human skin.
This is a key example of why personal protective equipment is essential, and why operators must be required to wear the appropriate gear. Learning techniques from a competent instructor can also reduce the potential for injury.
- Bursting Abrasive Wheels
A bursting wheel has the potential to be fatal for the operative or anyone within its vicinity. This is a particular risk with new wheels, and it can be controlled with practices such as ensuring the wheels are run within the suggested speed parameters and providing the appropriate guarding.
Additionally, appropriate abrasive wheel training must be provided (this is a legal requirement). This will help staff learn the correct procedures involved, such as handling and mounting the wheels.
When in use, abrasive wheels can create sparks. This has the potential to lead to fires or even explosions if their surroundings aren’t keep clean and ventilated.
In order to protect against this, it is the duty of both the employer and those using the wheels to ensure clean, well-ventilated working environment. Personal protective equipment (PPE) such as gloves and eye protection should also be worn, and any guarding should be in place.
- Reduced Blood Circulation
The vibrations associated with abrasive wheel operation can occur when the incorrect type, size or weight of wheel is used with the machinery. Loose bearings are also a possible cause of this, as well as a faulty wheel design.
All of this can cause discomfort and in some circumstances, it can also result in a condition known as hand-arm vibration syndrome (HAVS).
“HAVS is a painful and disabling condition that affects the nerves, blood vessels, muscles and joints of the hands and arms. It causes tingling and numbness in the fingers, reduces grip strength and the sense of touch, and affects the blood circulation” (HSE)
To avoid this, it is important that the correct wheel type is chosen. If the operator is beginning to feel discomfort or tingling as a result of their job task, they should report this to management immediately.
- Dust and Gas Inhalation
Although this does depend on the material in question, dust and gas inhalation can affect the health of the operator and cause serious consequences to their health.
Because of this, it is important to manage the environment they’re working in, again ensuring that it is well ventilated. The operative must also wear the appropriate respiratory protective equipment (RPE)for the task at hand.
Download HSE Guidance on the Use of Abrasive Wheel here