Metal cutting process, the correct choice of cutting fluid to reduce cutting forces, friction, and to take the heat to reduce the cutting temperature, reducing tool wear and improve tool life, improve the surface roughness to ensure the accuracy of the work piece to achieve the best economic effects. Cutting fluid are mainly the following four aspects of the role:
Cooling effect
Cutting fluid and heat convection between the tool, chip and work piece and vaporization of the role of cutting tropical walk, thus effectively reducing the cutting temperature, reduce the thermal deformation of the work piece and tool, keeping the tool hardness and improve the processing precision and durability of the tool .
The cooling performance of the cutting fluid and its thermal conductivity, specific heat capacity, heat of vaporization, and the fluidity (viscosity). Water-based cutting fluid cooling performance is better than oil-based.
Cutting fluid is on the tip of cutting invasive cool effect. The infiltrative good cutting fluid can spread rapidly to the tool and the work piece or the tool and chip contact gap, enhance the cooling effect. Joined the effective surface active agent can make cutting fluid infiltration is greatly improved. In addition, the cooling effect of the cutting fluid and its bubble (bubble air, the thermal conductivity of the air is worse than water), foam and more of the cutting fluid, the cooling performance of backward. In synthetic cutting fluids often add a small amount of silicone emulsion defamer.
In addition, changing the liquid flow rate and flow of traffic conditions, can effectively improve the cooling effect of cutting fluid; spray cooling liquid easily vaporized, can significantly improve the cooling performance.
Lubrication
Lubrication means: cutting fluid to reduce the rake face and chip, flank and the processing of the friction between surfaces, formed part of the role of the lubricant film. Good lubrication of the cutting fluid to reduce friction and power consumption, tool wear, better work piece surface quality.
Usually oil based cutting fluid lubrication properties than water-based, by adding oil and extreme pressure additives, oil based cutting fluid lubrication performance better.
The main component of the oil additives play the role of isolation tool and the work piece, the chip is a long chain with a polar organic compounds (such as higher fatty acids, higher alcohols, etc.), the formation of a layer of adsorbed film on the metal surface through the polar , thereby reducing friction and cutting force. For low-speed, low temperature, the precision cutting of occasions the use of oil additives, and temperatures in excess of 200 o C, the adsorbed film will be destroyed and loss of lubrication.
The main component of the extreme pressure additives that contain compounds of sulfur, phosphorus, chlorine and other elements (such as chlorinated paraffin’s, sulfur zed fats, phosphate), they can react chemically with the metal surface under high temperature and pressure conditions to generate the chloride of iron sulfide low iron phosphate geometric shear strength of the iron compounds that can prevent the tool and the work piece cold welding imaging also reduces the friction between the tool and the work piece, chip and inhibit the formation of BUE.
Cutting fluid lubrication and its permeability good cutting fluid can seep into the tip of the cutting area to form a lubricating film to reduce the cutting resistance and friction coefficient.