Cutting processes that use odorless cutting fluids

Cutting processes that use odorless cutting fluids

Honing is a precision finishing process for holes that demands high accuracy. Honing is a low-speed, low-feed cutting operation in which the tool and hole wall undergo an extrusion-cutting action. As a result, chips tend to accumulate in the tool flutes or adhere to the cutting edges, thereby affecting the extruded edge. This can degrade machining accuracy and surface roughness, increase cutting torque, and even lead to the formation of built-up edges, accelerating tool wear. Boring generally operates under boundary lubrication conditions; therefore, it is typically performed using highly concentrated extreme-pressure emulsions or extreme-pressure cutting oils that offer excellent lubricity and adequate fluidity, yielding superior results. A high-performance, odorless composite extreme-pressure cutting oil is particularly suitable for stainless steel and heat-resistant steels. For deep-hole honing, using deep-hole drilling fluids with excellent lubricating properties can effectively meet the process requirements.

Broaching is a machining process that uses a blade with teeth arranged along its axis and a multi-tooth tool. A key feature of broaching is its high machining accuracy, making it suitable for workpieces with complex shapes. Since the broach is a valuable cutting tool, its durability significantly impacts production costs. Moreover, broaching is a precision finishing process that places stringent requirements on the surface roughness of the workpiece. Broaching involves high cutting resistance, makes chip removal difficult, and often suffers from poor cooling conditions, which can easily lead to scratches on the workpiece surface. Therefore, odorless cutting oils with excellent lubrication and chip-removal properties are particularly well-suited for this process. In China, there is a special sulfur-containing extreme-pressure additive for broaching oils.

For broaches used on stainless steel and heat-resistant alloys, the following formulation (by mass fraction) can be adopted: 20% JQ2 extreme-pressure lubricant, 15% chlorinated paraffin, 1% Spylene 80, and 64% L-ANN22 total-loss system oil.

Generally, twist drills are used for drilling, which is considered a rough-machining process. In this process, chip removal is difficult, and cutting heat tends to build up easily, often leading to blade annealing. This, in turn, shortens the tool’s service life and reduces machining efficiency. By using high-quality, odorless cutting fluids, the tool’s service life can be extended several times—or even much more—and productivity can be significantly improved. Typically, extreme-pressure emulsions or extreme-pressure synthetic odorless cutting fluids are recommended. Extreme-pressure synthetic odorless cutting fluids have low surface tension and excellent permeability, enabling them to cool the drill bit promptly, extend tool life, and enhance machining efficiency. For difficult-to-cut materials such as stainless steel and heat-resistant alloys, low-viscosity extreme-pressure cutting fluids are advisable.

When threading, the cutting tool makes wedge-shaped contact with the workpiece material. The cutting blade is surrounded on three sides by the workpiece material, resulting in high cutting torque and relatively difficult chip removal. Heat generated during machining cannot be efficiently removed through chip evacuation, leading to rapid tool wear, accumulation of chip debris, and a tendency toward vibration. Particularly under demanding cutting conditions, chipping and thread breakage may occur. Odorless cutting oils, characterized by low friction coefficients and high extreme-pressure performance, can significantly reduce tool friction resistance and extend tool life. Generally, it is advisable to select composite odorless cutting oils containing both oil additives and extreme-pressure agents. Moreover, the permeability of odorless cutting oils used for tapping is crucial; how promptly the oil can penetrate into the cutting blade greatly influences the durability of the tapping operation. The permeability of an odorless cutting oil is closely related to its viscosity—oils with lower viscosity tend to have better permeability. If necessary, a small amount of diesel or kerosene can be added to enhance the oil's penetration effect. In certain situations, such as tapping blind holes, it can be challenging for the odorless cutting oil to enter the hole thoroughly. In such cases, an odorless cutting oil with high viscosity and strong adhesion properties would be the optimal choice.