By: Willy Goellner, Chairman & Founder—Advanced Machine & Engineering/AMSAW

Sawing metals is challenging. Friction between the carbide tips on a circular saw blade and the metal creates extreme temperatures. The temperatures affect the molecular structure of the teeth causing them to wear. Cooling the cutting edges of the blade with a flood cooling system extends tool life; however, the carbide tips can only be completely flooded when the blade enters and exits the material.

In the full cross section of the cut, a full coolant flow is not guaranteed because the carbide tips heat up and cool down every time they leave the material. This extreme temperature fluctuation of the cutting edges creates heat cracks that prematurely destroy the tips.

Minimum Quantity Lubrication (MQL) is better for circular cold saws, especially when cutting chrome, nickel, titanium, and stainless steel. These metals create extreme heat on the cutting edge of the saw blade when cut. The chips that are produced become red hot and weld to the carbide tip of the blade, making them difficult to be removed by brushes or compressed air.

When the chips do break from the weld, they take a small portion of the carbide tip. This weakens the carbide tooth and eventually breaks it. MQL reduces the friction on the cutting edge, thus reducing the heat and preventing the chips from welding to the carbide tips. Using MQL on the hard-coated carbide tips also make it possible for them to cut stainless steel.  

MQL is more environmentally friendly because it doesn’t require smoke separators or chip drainage. The thin layer of lubricant produces clean, dry chips that are worth more when recycled because they don’t require extra cleaning. Machinists don’t have to worry about potential health risks with repeated exposure to MQL as they would with flood coolant.

Studies have also shown that the cumulative costs of coolants and metalworking fluids can equal as high as 15 percent of the total cost to produce a part.

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