When and Why to Filter

In grinding operations you want to filter out all the particles that are larger than 10% of the grit size of the wheel or 10% of the tightest dimension specified.  A way to explain this is the tire and 2x4 analogy. An automotive tire is about twenty inches in diameter. If you run over the two-inch dimension (10%) of a 2x4 you will feel a bump.  The little divider bumps (wake-up bumps, turtles) in roads are generally much less than an inch and you sure feel those.  If particles of any size come between the tool and the work it will tend to damage both the tool and the surface of the work the same way that a rock in your shoe will try to make a hole in both your foot and the shoe.  Filtering Machine Coolant traps particles that may damage the tool and work surface.  Return to the Machine Coolant Filtration Index to read more articles about Filtering Machine Coolant and Machine Coolant Management Programs.

Machine damage is much harder to quantify.  One way of determining acceptable particle size is to ask what grit sandpaper you would allow to be used on the hydraulic cylinders of the machine.  As the machine coolant gets sprayed it gets on extended hydraulic cylinders and is then abraded as the cylinder moves in and out.