A few months ago, we discussed the dangers of metal fumes and dust. However, not everyone knows how many different types of metal particles there are. This is why we thought we’d discuss them, specifically the types of metal particles generated during metal grinding.
What is Metal Grinding?
Metal grinding is a process used to smoothen and finish of metal parts, most often used for finishing edges, deburring, smoothening welding joints, creating a sharp edge, and for certain custom edge finishes.
The different types of grinders used in metal grinding are:
- Belt grinder: Uses a belt with an abrasive coating to grind metal for surface finishes.
- Bench grinder: A benchtop grinder, it drives abrasive wheels to hand grind tools and other types of rough grinding.
- Cylinder grinder: A cylindrical grinder is used to shape the outer surfaces of objects.
- Surface grinder: An abrasive wheel used to finish the surface of flat surfaces.
- Bit grinder: Used to sharpen tool bits and milling cutters.
- Jig grinder: Used for grinding complex shapes, where accuracy and finish are important.
What Are the Different Types of Metal Particles from Grinding?
Metal particles (or metal dust) can be classified based on their size, into:
- Metal swarf
- Inhalable dust
- Respirable dust
Metal Swarf
Swarf refers to larger particles, like metal chips, filings, and turnings. Metal swarf ranges from spring-like tendrils to gritty dust. The main thing to bear in mind while handling swarf is the sharp edges, which can lead to injuries.
However, even the smaller bits can get under the skin as splinters, which is why it is advised never to handle metal swarf with bare hands.
Inhalable Dust
At the smaller end of the metal swarf spectrum lies inhalable metal dust. This is made up of particles that are 100 microns to 30 microns in size. For reference, human hair ranges from 17 microns to 180 microns. As you can see, these particles are fairly big and can be quite irritating if they get in the eyes, nose, or throat.
Respirable Dust
Respirable dust, as the name suggests, is very fine dust that is typically around 1 micron to 0.1 microns. This dust, created by fine metal grinding processes, can pass through the nasal passage into the alveoli of human lungs, where it can cause long-term problems.
These are the different types of metal particles created from grinding processes. However, there is another term you might have heard in reference to metal dust – combustible metal dust.
Combustible Metal Dust
Now, on the face of it, metal does not seem to be combustible. The fact is, fine metal dust, especially of certain metals, like Aluminium, Titanium, and Magnesium, can be extremely flammable and can burn at a very high temperature, ranging from 2760 degrees C to 4426 degrees C.
At such high temperatures, using water to try and put out the fire can actually be dangerous, as water disintegrates into hydrogen and oxygen when super-heated. Hydrogen is extremely combustible (to the point of being explosive) and oxygen is a necessary component of combustion, which is a dangerous mix.
This is why metal dust extraction requires certain precautions. First, we need to ensure that there are no ignition triggers. The metal grinding process needs to have a lubricant so that the metal and the grinder don’t get hot or create sparks. Second, the dust might need wet extraction so it cannot form a combustible cloud.
At VODEX, we offer a range of extraction solutions for metal dusts, as well as fumes for all your needs.
