Oil based cutting fluid has good lubrication performance and poor cooling effect. Compared with oil based cutting fluid, water-based cutting fluid has relatively poor lubrication performance and good cooling effect. Slow cutting requires strong lubrication of cutting fluid. Generally speaking, cutting oil is used when the cutting speed is lower than 30m/min. Cutting oil containing extreme pressure additive is effective for cutting any material when the cutting speed does not exceed 60m/min. During high-speed cutting, due to the large heat generation and poor heat transfer effect of oil-based cutting fluid, the temperature in the cutting area will be too high, which will lead to smoke, fire and other phenomena in the cutting oil. In addition, because the workpiece temperature is too high, thermal deformation will occur, which will affect the machining accuracy of the workpiece, so water-based cutting fluid is used more.
No. 1 Advantages and disadvantages of emulsion Emulsion combines the lubricity and rust resistance of oil with the excellent cooling property of water, and has good lubricity and cooling property, so it is very effective for metal cutting with high speed and low pressure generated by a large amount of heat. Compared with oil-based cutting fluid, emulsion has the advantages of greater heat dissipation, cleaning, economy brought by dilution with water, and it is beneficial to the health and safety of operators, so that they are willing to use it. In fact, except for materials that are particularly difficult to machine, emulsion can be used for almost all light and medium load machining and most heavy load machining. Emulsion can also be used for all grinding processes except for complex grinding such as thread grinding, groove hemp cutting, etc. The disadvantage of emulsion is that it is easy for bacteria and molds to multiply, and the effective components in the emulsion will be decomposed chemically to stink and deteriorate. Therefore, organic bactericides with low toxicity should be added generally.
No. 2 Advantages and disadvantages of chemical synthesized cutting fluid The advantages of chemical synthetic cutting fluid lie in its economy, fast heat dissipation, strong cleanability, excellent workpiece visibility, easy control of machining size, and better stability and anti-corruption ability than emulsion. The disadvantage of chemically synthesized cutting fluid is poor lubrication, which will cause adhesion and wear of moving parts of the machine tool. In addition, the viscous residues left by chemical synthesis will affect the movement of machine parts, and will also cause corrosion on the overlapping surfaces of these parts.
No.3 Selection of water-based cutting fluid and oil-based cutting fluid Generally, water-based cutting fluid shall be selected under the following conditions: Places with potential fire hazard to oil-based cutting fluid. High speed and large feed rate cutting makes the cutting area exceed the high temperature, smoke is fierce, and there is a fire hazard. In consideration of the process flow of the previous and subsequent processes, the use of water-based cutting fluid is required. It is hoped to reduce the pollution and dirt around the machine tool caused by the splash and diffusion of oil, so as to keep the operating environment clean. From the price point of view, for the cutting of some free machining materials that do not require high surface quality of the workpiece, the use of general water-based cutting fluid can meet the requirements of use and can greatly reduce the cost of cutting fluid.
Generally, oil-based cutting fluid shall be selected under the following conditions: When the durability of cutting tools accounts for a large proportion of the economy of cutting (such as expensive tools, difficult tool grinding, long loading and unloading auxiliary time, etc.). The machine tool is of high precision, and no water is allowed to mix (to avoid corrosion). Where the lubrication system and cooling system of the machine tool are easy to communicate, and where there is no waste liquid treatment equipment and conditions.
