We must first understand the characteristics of oil-based and water-based cutting fluids. Generally speaking, oil-based cutting fluids have good lubricating properties, while water-based cutting fluids have good cooling properties, and emulsions have certain lubricity and rust resistance, as well as certain cooling and cleaning properties, but are prone to microorganisms And decomposition and deterioration occurred.
Mainly consider the choice of cutting fluid from the following aspects
The process lubricants used in the process of cutting, forming, processing and protecting metals and their alloys are collectively called metal working fluids, also known as cutting fluids. In the process of metal processing, in order to reduce the cutting force during cutting, and take away the heat generated in the cutting area in time to reduce the cutting temperature, improve the durability of the tool, thereby improving the production efficiency, improving the surface roughness of the workpiece to be optimized Economic effects.
1. Selection according to workpiece material
Machining-The machinability of the workpiece material to the choice of cutting fluid: The machinability of the workpiece material is of great significance to the choice of cutting fluid. The specific conditions and requirements of cutting are different, and the degree of difficulty of cutting is different. When roughing, it requires slow tool wear and high processing productivity; when finishing, it requires high precision and small surface roughness of the workpiece.
Choose a cutting fluid with high activity, anti-wear and extreme pressure additives for materials that are difficult to process; use a cutting fluid that does not contain extreme pressure additives for materials that are easy to process.
When cutting non-ferrous metals and light metals, the cutting force and cutting temperature are not high, and mineral oil and high-concentration emulsion can be used. When cutting alloy steel, if the cutting amount is low and the surface roughness requirements are small (such as broaching and thread cutting), cutting fluid with excellent lubricating properties is needed at this time. Extreme pressure cutting oil and high-concentration emulsion can be selected. When cutting brittle materials such as cast iron and bronze, chipping chips are often formed during cutting, which easily flows with the cutting fluid and flows between the machine tool rails to cause component damage. Low-concentration emulsions with good cooling and cleaning performance can be used.
Second, choose according to the method of the workpiece
Rough machining with higher cutting speed (for example: turning, milling, drilling) requires that the cutting fluid has good cooling performance. At this time, water-based cutting fluid and low-concentration emulsion should be selected. In some precise high-strength machining (for example: broaching, tapping, deep hole drilling, gear machining), the cutting fluid needs to have excellent lubrication performance at this time, extreme pressure cutting oil and high-concentration emulsion can be selected.
Third, choose according to the tool material
1. Tool steel cutter
The heat resistance temperature of this kind of tool is 200-300oC, the heat resistance is poor, and the hardness will be lost at high temperature, so it is required to use cutting fluid with good cooling performance, and low concentration emulsion is suitable.
2. High speed steel cutter
During high-speed rough cutting, the amount of cutting is large and a large amount of cutting heat is generated. In order to avoid workpiece burns and affect the processing quality, water-based cutting fluid with good cooling performance should be used; if high-speed steel tools are used for medium and low-speed finishing, it is To reduce the frictional adhesion between the tool and the workpiece, to suppress the formation of cutting tumors, and to improve the machining accuracy, oil-based cutting fluid or high-concentration emulsion is generally adopted.
3. Carbide cutting tools
This kind of tool has higher melting point and hardness, better chemical and thermal stability, and better cutting and wear resistance than high speed steel tool. Oil-based cutting fluid can be used in general machining. If it is heavy cutting, the cutting temperature is very high, and it is easy to wear the tool very quickly. At this time, use a sufficient flow of cooling lubricant, preferably 3% -5% emulsion (use spray cooling, the effect is better).
4. Ceramic tools, diamond tools, cubic boron nitride tools
These tools have high hardness and wear resistance. Generally, cutting fluid is not used during cutting, and sometimes water-based cutting fluid can also be used.
Fourth, choose according to machine requirements
When choosing cutting fluid, we must consider whether the machine tool structure is suitable. Generally, the type of cutting fluid specified in the machine tool manual should be followed. If there is no special reason, do not change it easily to avoid damage to the machine tool.
V. Selection according to economic benefits
Choosing the cutting fluid must carry out a comprehensive economic analysis to correctly evaluate the economic benefits of the cutting fluid. The costs are roughly as follows: the cost of purchasing cutting fluid, the management cost of cutting fluid, the cost of cutting tool wear, the improvement of production efficiency, the life cycle of cutting fluid, and the cost of disposal of cutting fluid.
In the total cost of processed products, the cost of buying cutting fluid only accounts for a small part. If the cutting fluid is selected correctly, the product quality and operating environment are improved, the processing efficiency is increased, the durability of the tool is extended, and the cutting fluid is reduced. Replenishment and management costs ... thus bringing significant economic benefits. If it is not selected properly, it will have the opposite effect. Therefore, a comprehensive economic analysis is required.
VI. Other considerations
If oil-based cutting fluid is selected, fire safety needs to be emphasized; if water-based cutting fluid is selected, the discharge of cutting fluid should be considered, and enterprises should have waste fluid treatment facilities and take corresponding measures.
In addition, regulations such as the Safety and Health Law, the Fire Protection Law, and the Wastewater Discharge Law need to be followed.