The daily management of water-based cutting fluids requires special attention to the following issues: 1. Concentration management Water-based cutting fluid should be used within a certain concentration range, otherwise it not only cannot fully exert its function, but also causes various troubles. Using at excessively high concentrations not only increases costs, but also results in sludge formation due to the mixing of oil spills, making filtration difficult. If the concentration is too low, it will cause cutting performance problems, such as shortened tool durability and deteriorating dimensional accuracy. In addition, if the concentration is too low, the rust resistance will also decrease, causing corrosion. And the cutting fluid is also prone to decay. Therefore, maintaining the specified concentration of water-based cutting fluid is a very important task. Doing a good job in concentration management can extend the lifespan of cutting tools and usage fluids, reduce costs, and thus reduce waste liquid emissions.
2. Rust prevention management Water-based cutting fluid is diluted with water as the diluent. If the diluted water contains a large amount of sodium chloride and sulfate, it is not only easy to cause the use of liquid corruption, but also reduces its rust resistance. Therefore, it is hoped that diluted water has better water quality than tap water. If the concentration of the liquid used is extremely thin or its composition is unbalanced, its rust prevention performance will inevitably decrease. In this sense, rust resistance is an indicator of the deterioration of the liquid used. When the rust resistance decreases, the general measure taken is to supplement the original solution to increase the concentration. In situations where the rust prevention time of water-based cutting fluid is short, the workpiece stays between processes for a long time, or the weather conditions suddenly change in an environment prone to rusting, rust prevention oil should be applied in advance to prevent corrosion.
3. Corrosion prevention management The frequent use of liquid replacement is due to corruption. The use of water-based cutting fluid is contaminated due to oil leakage and the mixing of chips, causing abnormal microbial growth and decay. The process is:
① Mild putrefaction odor (acid putrefaction) occurs; ② Changes in the appearance of the liquid used (grayish brown, peach color); ③ Rapid decrease in pH and rust resistance; ④ The generation of sediment or oily sludge like substances, blockage of filters, and separation of emulsions; ⑤ Decreased cutting (grinding) performance; ⑥ Produce a foul odor and worsen the working environment. At this point, it is necessary to change the usage fluid. The spoilage of water-based cutting fluid is the result of abnormal microbial reproduction, with aerobic bacteria being the most common and anaerobic bacteria also present. During use, the proliferation of aerobic bacteria reduces oxygen in the liquid, while on weekends and rest days, the liquid stops flowing and anaerobic bacteria continue to multiply, causing the liquid to smell. The original solution of water-based cutting fluid is heated and sterilized with fungicides during the manufacturing process. However, during use, diluted water, processed parts, dirt around the machine tool, hands of operators, and bacteria in the air are mixed in. In addition, the use of the fluid has appropriate temperature and nutrients such as carbon water compounds, minerals, proteins, etc., causing bacteria to continuously reproduce and even cause the use of the fluid to decay and deteriorate.
To prevent corruption, the first step is to choose a stock solution that contains substances that are prone to becoming microbial nutrients (such as phosphorus, sulfur, oil, mineral oil, etc.) and have antibacterial components. At the same time, preservatives with bactericidal or antibacterial effects must be used to prevent microbial reproduction. However, it must be noted that the concentration of preservatives with strong bactericidal power should not be too high, otherwise it may cause diseases for operators. There is currently no effective preservative for all microorganisms such as bacteria and molds, and if only a specific preservative is used, the number of drug-resistant bacteria will continue to increase, leading to a gradual decline in bactericidal efficacy. Therefore, relying solely on fungicides to prevent spoilage is not enough. Therefore, while selecting non perishable raw materials and using preservatives, the management of the used materials is essential. To prevent corruption, the liquid used must always be kept clean and at an appropriate concentration, and the following points should be noted. 1) When injecting new liquid, the dirt and impurities around the machine tool and in the liquid supply system should be thoroughly removed, and the new liquid can only be injected after being thoroughly washed with water containing fungicides. Otherwise, it is equivalent to adding spoilage bacteria to the new liquid. 2) Dilution water must be tap water or soft water, and underground water containing coliform bacteria and inorganic salts must be avoided, because the water quality has a great impact on the reproduction of bacteria. 3) To manage the supply liquid and ensure that the used liquid operates at the specified concentration. 4) When a decrease in pH is found, a pH regulator should be added to maintain it at a pH that is difficult for microorganisms to reproduce (such as around 9). 5) During holidays or long-term shutdowns, air should be regularly blown into the liquid tank to prevent anaerobic bacteria from breeding and causing odor. 6) Prevent oil leakage from entering and set up a device that can quickly remove the oil leakage that has already entered. 7) Adopt effective chip removal methods to avoid chip accumulation in the box. 8) If signs of corruption are found, fungicides should be added immediately. Fungicides can also be added regularly as needed.
