There are a variety of metalworking fluids circulating on the market. How to correctly select high-quality and suitable metalworking fluids and scientifically do cutting fluid maintenance and fluid control, so as to achieve the purpose of reducing enterprise costs, is a problem that many enterprises are facing.
How to choose the right metalworking fluid? Emulsions in general metalworking fluids are suitable for moderate to heavy duty cutting and grinding; semi-synthetic cutting fluids are suitable for most light to medium duty cutting and all types of grinding; fully synthetic cutting fluids are Only suitable for light duty cutting and light to medium grinding. 1. Analysis from the processing method In rough machining with high cutting speed (such as turning, milling and drilling), the cutting fluid is required to have good cooling properties. At this time, semi-synthetic cutting fluid and low-concentration emulsion should be used. In some precise and high-strength machining (such as broaching, tapping, deep hole drilling and gear machining), cutting fluids are required to have excellent lubricating properties, and high extreme pressure emulsions can be selected. 2. Analysis from the use of tools Tool Steel Knives The heat-resistant temperature of this type of tool is 200-300 °C, the heat-resistant performance is poor, and the hardness will be lost at high temperature. Therefore, it is required to use a cutting fluid with better cooling performance, preferably a low-concentration emulsion. High Speed Steel Tool During high-speed rough cutting, a large amount of cutting heat is generated. In order to avoid workpiece burns and affect processing quality, fully synthetic or semi-synthetic cutting fluids with good cooling properties should be used; when using high-speed steel tools for medium and low-speed finishing, in order to reduce the size of the tool Frictional bonding with the workpiece to inhibit the formation of cutting tumors, generally a high-concentration fully synthetic fluid is used. Carbide Tool Such tools have high melting point and hardness, and emulsions can be used in general processing. In the case of heavy cutting, the cutting temperature is very high, and the tool is easy to wear very quickly. At this time, a cooling lubricant with sufficient flow should be used, preferably an emulsion of 3% to 5% (spray cooling is used, the effect is better). Ceramic tools, diamond tools and cubic boron nitride tools These tools have high hardness and wear resistance, and generally do not use cutting fluids when cutting, and sometimes fully synthetic cutting fluids can be used. The cost of metalworking fluid accounts for about 7% to 17% of the total manufacturing cost. Reasonable selection of cost-effective metalworking fluids can effectively reduce manufacturing costs for enterprises. 2. Cutting fluid maintenance and fluid control Extend the life of the machining fluid and reduce costs through good maintenance. Make sure the machine tool and the water tank are clean before adding the liquid, then add a certain amount of water to the water tank, slowly add the cutting fluid according to the required concentration and stir thoroughly until the liquid has a uniform appearance. Precautions: Be sure to mix in a clean tank; be sure to pour oil into water and not the other way around; use diluent to adjust concentration. In actual use, the following parameters will change and need to be controlled: Exterior The change in appearance is mainly caused by external pollution. The gray or black color is mainly caused by the saponification of sulfate bacteria and metal particles, which is common in the processing of cast iron; the brownish yellow is related to the saponified iron; the creamy substance on the liquid surface indicates that the working fluid unstable.
Concentration The tighter the control, the better, because the operating cost is lower at 1% to 2% higher than the set concentration.
PH Value
The new fluid is usually between 9.2 and 9.5, and will drop to 9.0 to 9.2 soon after processing. Daily testing will help prolong the life of the working fluid, because a drop in pH is a sign of bacterial infection. If the PH value is lower than 8.7, measures should be taken to add fungicides.
Miscellaneous Oil
It mainly comes from the hydraulic and lubrication system of the machine tool, which will promote the growth of bacteria and affect the life of the tool and working fluid. It should be controlled within 2% and can be removed by oil skimmer and centrifugal methods.
Total Hardness
Depending on the total content of calcium and magnesium ions in the water, too high will affect the stability and foam level of the working fluid, and scum will result in the consumption of fatty acid soaps. The hardness can be reduced by adding softened water or reverse osmosis membranes. Usually, the hardness is reduced. Controlled at 5°dH ~ 30°dH.
Chlorine Content
If it is too high, it will cause rust and destroy the stability of the working fluid. It should be controlled within 150PPM. It can be solved by adding demineralized water and concentrate.
Conductivity
Too high will cause rust and destroy the stability of the working fluid, affecting the life of the tool. It should be controlled within 5000μS/cm, which can be solved by partial replacement and addition of demineralized water.
It can be seen that the life of metalworking fluid mainly depends on the control of foreign pollution and organic organisms. Good maintenance can double the life of metalworking fluid, so the benefits are very considerable. Seeing this, do you know how to correctly select metalworking fluid and maintain and control it? Unsuitable metalworking fluids will harm the equipment, increase the failure rate of the equipment, increase the maintenance cost, and shorten the service life of the equipment, which will lead to cost losses. Therefore, only by correctly selecting metalworking fluids and maintaining them well can enterprises achieve real cost reduction and efficiency increase!
