High quality metal working fluids can better assist processing. How to extend the service life of metal working fluids through effective chemical management and achieve the goal of reducing enterprise costs has attracted more and more attention from enterprises.
Choose a suitable metal working fluid.
Generally, emulsions in metal working fluids are suitable for cutting and grinding under moderate to heavy loads; Semi synthetic cutting fluid, suitable for most mild to moderate load cutting and all types of grinding; Fully synthetic cutting fluid is only suitable for light load cutting and light to moderate grinding processing.
1. Analysis from processing methods
In rough machining with higher cutting speeds (such as turning, milling, and drilling), it is required that the cutting fluid has good cooling performance. In this case, semi synthetic cutting fluid and low concentration emulsion should be selected.
In some precision high-strength machining processes (such as broaching, tapping, deep hole drilling, and gear machining), cutting fluids with excellent lubrication performance are required, and high extreme pressure emulsions can be selected.
2. From tool analysis
(1) Tool steel cutting tools: These types of cutting tools have a heat resistance temperature of 200-300 ℃, poor heat resistance, and will lose hardness at high temperatures. Therefore, it is required to use cutting fluids with good cooling performance, and low concentration emulsions are preferred.
(2) High speed steel cutting tools: During high-speed rough cutting, a large amount of cutting heat is generated. To avoid workpiece burns and affect machining quality, fully synthetic or semi synthetic cutting fluids with good cooling properties should be used; When using high-speed steel cutting tools for medium and low-speed precision machining, high concentration emulsions are generally used to reduce the friction and adhesion between the tool and the workpiece, and to suppress the generation of cutting nodules.
(3) Hard alloy cutting tools: These types of cutting tools have high melting points and hardness, and emulsions can be used in general machining. In case of heavy cutting, the cutting temperature is very high, and the tool is easy to wear very quickly. At this time, the cooling lubricant with sufficient flow should be used, and 3%~5% emulsion is appropriate (spray cooling is better).
(4) Ceramic tools, diamond tools, and cubic boron nitride tools: These tools have high hardness and wear resistance, and generally do not use cutting fluids during cutting. Sometimes, fully synthetic cutting fluids can also be used.
The cost of metal working fluid accounts for about 7% to 17% of the total manufacturing cost. Reasonable selection of metal working fluid with high cost-effectiveness can reduce manufacturing costs for enterprises in the first step.
Cutting fluid maintenance and fluid control.
Extend the service life of the processing fluid and reduce costs through good maintenance. Before mixing, confirm that the machine tool and water tank are clean, then add a certain amount of water to the water tank. Slowly add cutting fluid according to the required concentration and stir thoroughly until the liquid appearance is uniform and consistent.
Attention: Be sure to mix in a clean water tank; Be sure to pour oil into water instead of the opposite; Adjust the concentration with diluent.
In actual use, the following parameters will undergo changes that need to be controlled:
(1) Appearance:
The changes in appearance are mainly caused by external pollution, and gray or black are mainly caused by sulfate bacteria and metal particle saponification, which are common in cast iron processing; Brown yellow is related to saponified iron; The presence of creamy substances on the liquid surface indicates that the working fluid is unstable.
(2) Concentration:
The stricter the control, the better, because operating costs are lower when the concentration is 1% to 2% higher than the set concentration.
(3) PH value:
The new liquid is usually between 9.2-9.5, and it quickly drops to 9.0-9.2 after processing. Daily testing can help extend the lifespan of the working liquid, as a decrease in pH value is a sign of bacterial infection. If the pH value is below 8.7, measures should be taken to add fungicides.
(4) Miscellaneous oil:
Mainly from the hydraulic and lubrication systems of machine tools, it can promote bacterial growth and affect the lifespan of cutting tools and working fluids. It should be controlled within 2% and can be removed using skimmers and centrifugation methods.
(5) Total hardness:
Depending on the total content of calcium and magnesium ions in the water, too high will affect the stability of the working fluid and the level of foam, resulting in scum that will lead to the consumption of fatty acid soap. The hardness can be reduced by adding softened water or reverse osmosis membrane, and the hardness is usually controlled at 5°dH~30°dH.
(6) Chlorine content:
Excessive temperature can cause rust and damage the stability of the working fluid, which should be controlled within 150PPM. The solution can be achieved by adding softened water and concentrated solution.
(7) Conductivity:
Excessive temperature can cause rust and damage the stability of the working fluid, affecting the tool life. Should be controlled at 5000 μ Within S/cm, partial replacement and addition of softened water can be used to solve the problem.
summary
From this, it can be seen that the lifespan of metal working fluids mainly depends on the control of external pollution and organic organisms. Practice has shown that good maintenance can prolong the lifespan of metal working fluids by one time, and the benefits generated can be seen.
