intro to metal cutting fluids

active oils

an oil that releases sulfur during machining to lubricate the cutting tool, workpiece, and chips. Active oils are used in applications where the chips are likely to crowd, such as in threading.

refractometer

an optical instrument used to measure the chemical or oil concentration in a miscible cutting fluid. It uses a Brix scale to assess the amount of concentrate in a cutting fluid.

oils that can be mixed with water

are referred to as emulsifiable oils, or soluble oils, and are water-miscible due to specialized additives called emulsifiers. They are suspensions of oil, water, and soap-like material, and contain 60 to 90% water

the desired PH range of cutting fluid is

between 8.7 and 9.2, which is slightly alkaline

what is an important characteristic used to separate cutting fluids on a cutting fluid chart?

compatible metals

cutting fluids can be divided into two categories

cutting oils and water-miscible fluids, known collectively as metalworking fluids (MWF)

HPHV

high-pressure, high-volume method. A method of fluid delivery in which fluid is forced through the nozzle at high speeds. The HPHV method is used in severe machining applications that require particularly effective cooling and lubrication.

sulfurized mineral oil

is a type of active cutting oil used for machining tough, ductile metal

water hardness

measures the amount of calcium or magnesium present in water in parts per million (ppm). Medium-soft water (50-75 ppm) is recommended for best cutting fluid results

common chemical additives include:

nitrites (to prevent rust) phosphates (to soften water) soaps (to provide added lubrication) biocides (to control bacteria growth) defoamers (to reduce excess bubble formation)

cutting oils

sometimes called "straight" oils because they are not mixed with water. Two types are inactive oils and active oils. Cutting oils contain no water.

this fluid lasts the longest and can be recycled many times

straight oils

inactive oils

a cutting oil that releases very little lubricating sulfur during machining. Inactive oils are mostly used for light-duty machining on non-ferrous metals

ring-distributor method

a fluid delivery method that routes fluid through small holes in a tube around the cutting tool. The ring-distributor method is often used with round cutting tools, such as mills

flood method

a method of fluid delivery in which the cutting fluid is routed through nozzles and completely covers the workpiece and the cutting tool. The flood method is the most commonly used cutting fluid delivery system

fluid cleaning devices include

a skimmer, vacuum filter units, magnetic cleaners, and centrifuges

semi-chemical fluids

a water-based cutting fluid containing a mixture of chemicals and soluble oil. Semi-chemical fluids, also called semi-synthetic fluids, are used in applications where lubrication and cooling are equally important, such as heavy-duty machining. Include plain and super-fatted fluids, have high detergency that can irritate skin.

chemical fluid

aka synthetic fluid, is made from water and chemicals, such as nitrites, phosphates, and defoamers. Chemical fluids are primarily used for their ability to cool. They resist dissolving tramp oil

through-hole HPHV

A method of fluid delivery in which fluid is delivered through channels or holes in the tool. Through-hole HPHV is used when the cutting surface would be unreachable by other methods