Water based cutting fluid is mainly cold cutting, supplemented by lubrication, including cutting fluid (aqueous solution) and emulsion. Emulsion is the most commonly used in milling. Oil based cutting fluid is mainly lubrication, supplemented by cooling, including cutting oil and extreme pressure oil. Cutting oil is the most commonly used in milling.
Emulsion: emulsion is a milky white liquid diluted by emulsified oil with water. A certain has good fluidity, large specific heat capacity, low viscosity, good cooling effect and certain lubricating performance. It is mainly used for cutting steel, cast iron and non-ferrous metals.
Cutting oil: cutting oil is mainly mineral oil, and other animal, vegetable oil and composite oil. Cutting oil has good lubrication performance, but its fluidity and specific heat capacity are small, and its heat dissipation effect is poor.
Cutting fluid should be selected reasonably according to the specific conditions such as workpiece material, tool material, processing method and requirements.
(1) During rough machining, the cutting allowance is large, the heat is generated, the temperature is high, and the requirements for the quality of the machined surface are not high, so the cutting fluid based on cooling should be used. When finishing, the machining allowance is small, the heat generated is small, the cooling effect is not high, but the surface quality of the workpiece is high, and the milling cutter is expected to be durable, so the cutting fluid based on lubrication should be used.
(2) When milling brittle materials such as cast iron and brass, cutting fluid is generally not used, and kerosene, emulsion and compressed air can be used when necessary.
(3) When using carbide milling cutter for high-speed cutting, generally do not use cutting fluid, use emulsion when necessary, and pour continuously and fully before cutting, so as to prevent the blade from cracking due to sudden cooling.
Selection of cutting fluid during milling
1. Carbon steel: emulsion and soda water are used during rough milling. Emulsion (mass fraction of 10% - 15% at low speed and 5% at high speed), extreme pressure emulsion, compound oil, vulcanized oil, etc. are used during fine milling.
2. Alloy steel: emulsions and extreme pressure emulsions are used during rough milling. Emulsion (mass fraction of 10% - 15% at low speed and 5% at high speed), extreme pressure emulsion, compound oil, vulcanized oil, etc. are used during fine milling.
3. Alloy steel: emulsion, extreme pressure cutting oil, vulcanization emulsion and extreme pressure emulsion are used during rough milling. Chlorinated kerosene is used for finish milling, and kerosene is added with 25% vegetable oil; Kerosene plus 20% turpentine and 20% oleic acid, EP emulsion. Vulcanized oil (diesel plus 20% fat and 5% sulfur), extreme pressure cutting oil.
4. Cast steel: emulsion, plate pressing emulsion and soda water are used during rough milling. Emulsion, extreme pressure cutting oil and compound oil can be used during finish milling.
5. Bronze and brass: this kind of metal can be processed without cutting fluid, and emulsion, sulfur-containing emulsion, polarization, pressure fluid and emulsion can be used when necessary.
6. Aluminum: generally, aluminum processing is not required. If necessary, emulsion and compound oil can be used. Diesel oil, compound oil, kerosene and turpentine are used for finish milling.
7. Cast iron: generally, cutting fluid is not needed in processing, and compressed air or emulsion is used when necessary. Generally, it is not used during fine milling, and compressed air or emulsion or extreme pressure emulsion is used when necessary.