A great number of industrial processes such as grinding, milling and turning create heat and particles.  Machine coolants are used to keep the work surface cool and to carry away chips and particles.  Filtering Machine Coolant traps the small particles that get recirculated with the coolant and can cause damage to the tools and equipment.  For more information on filtering take a look at some of our articles in the Machine Coolant Index.

Saws and other tools are commonly carbide tipped.  The tungsten carbide used is man-made material and it is the closest substance to diamond available.  It has much more give so it does not break as easily as diamond.  Tungsten carbide saw tips are brazed onto the steel saw body and then they are ground to make them sharp.

The tungsten carbide saw tips are actually very small pieces of tungsten carbide that are held in a matrix of cobalt.  The cobalt is like the caramel in a popcorn ball.  

The grinders are flood cooled which means that water is flooded over the work area.  This cools the work and washes particles out of the way.  The liquid is typically 90 to 95% water and 5 to 10% machine coolant.  The liquid runs over the work area and then down the machine where it collects in a sump at the bottom of the machine.  The liquid is pumped out of the sump and constantly recirculated.   As the tip is ground, the tungsten carbide and the cobalt collect in the sump.

Far and away the majority of machining is done with carbide or ceramic tools.  These tools wear and micro-chip in use.  Machining creates chips.

Machining creates big chips.   Everyone has some sort of program to handle big chips.  Even the worst shops shovel them out of the way when they start to bury the machine.   Unfortunately many, many people think that all you need to do is to remove the big chips.  Every big chip means lots of small chips the same way boulders are surrounded by little rocks.  It is the little chips that do the most damage. 

Several hundred times more damage is done by chips too little to see than is done by big chips.           

There are a million to a million and a half people in the US who are exposed to grinding and machining machine coolants.  These machine coolants and their contaminants cause skin rashes, allergic reactions, epidermal scarring, lung scarring, emphysema, severe emphysema and death. 

The use of cutting, grinding and machining fluids results in the estimated creation of well over ten million gallons of waste annually.

Principles of Filtration

Filtration is the process in which particles are separated from a fluid by passing the fluid through a permeable material. There are also non-filtration separation methods such as gravity settling or flotation, the use of centrifugal force as in a cyclone or centrifuge, and processes such as ion exchange or reverse osmosis for the removal of dissolved solids.

There are four basic reasons why liquids are filtered:

(1) To save the solids and discard the liquid

(2) To save the liquid and discard the solids

(3) To save both

(4) To save neither.