Adding cutting fluid is also a technical activity, how to control the pH value?
May 18, 2022
Metalworking fluids include cutting fluids, cutting oils, cleaning agents, and rust-preventive oils, etc., with a wide range, and daily maintenance and maintenance are different. This article focuses on how to reduce the fluctuation of cutting fluid concentration and how to replace the cutting fluid. 1. How to reduce the concentration fluctuation of cutting fluid? Any brand or type of cutting fluid has the manufacturer's recommended concentration range, which is not only related to the cutting fluid itself, but also directly related to the processing technology. It is recommended that the concentration of cutting fluid be strictly controlled within the recommended range during routine maintenance. For processes with high requirements for finishing or machining quality, an appropriate increase of 1% to 2% is based on the range recommended by the manufacturer, which will not only reduce the Concentration fluctuations will affect the machining quality and tool life, and it will also effectively extend the life of the cutting fluid.
In fact, the maintenance cost of cutting fluid is not as much as imagined. The reason is that most of the evaporated water during processing is water, so under normal circumstances, the concentration of replenishment fluid will be much lower than the recommended concentration. PART.1 Control of liquid level and concentration 1. Maintain a reasonable liquid level. Generally speaking, the liquid level of the centralized liquid supply system is controlled between 60% and 80% of the liquid tank capacity; the liquid level of a single machine should not be lower than 80% of the liquid tank capacity. 2. Set the target value, that is, the middle value of the concentration range; if it is lower than this value, fluid should be added. 3. When adding liquid, it is recommended to use a mixer. If there is no mixer, it should be added at the maximum flow rate when adding liquid, so that the stock solution can be dispersed as soon as possible. PART.2 Monitor the pH value of cutting fluid The pH value of cutting fluid is like human body temperature, too low or too high is unfavorable. Generally speaking, the optimal range of cutting fluid is between 8.8 and 9.5. However, when there is a problem with cutting fluid, it is more "low fever", especially in summer when the operating rate is not high, the probability of pH reduction will be more. PART.3 Measures to reduce pH value 1. It is still within the controllable range, the concentration can be appropriately increased by 1%~2%, and the management of oil slick and regular circulation can be strengthened. 2. When the pH value is between 8.5 and 8.8, an appropriate amount of the pH enhancer specified by the manufacturer can be added, and the microbial content can be detected. 2. How to replace the cutting fluid? PART.1 Recommended replacement cycle During high temperature in summer and rainy season, it is recommended to change the fluid once a month and a half; The fluid change cycle in winter can reach more than three months; In other seasons, it is replaced every two months. PART.2 Precautions for replacing cutting fluid 1. Machine tool cleaning before replacement. The old cutting fluid to be replaced often contains a large amount of machining metal powder and dirt, and a certain amount of machining debris and dirt are also accumulated inside the machine tool pipeline. After the liquid is drained, shovel the chips in the groove and remove the debris by hand. The system is cleaned to prevent contamination of the new fluid, which can cause rapid spoilage of the new fluid. For system cleaning, system cleaning agent must be added to clean the system, and the working fluid pump must be turned on to circulate for several hours. Make sure bacteria, yeast, and fungus are removed from the pipes. 2. Use the new cutting fluid with a concentration of more than 10% to thoroughly scrub the machine tool, especially the chip groove and the full circle of the chip conveyor track, to remove the residual dirty oil. Finally, use the new cutting fluid to scrub the bottom and side walls of the fluid tank, and there should be no dirty oil residue, and rinse with water. 3. For precision grinders, the temperature of the newly added metalworking fluid should be adjusted to room temperature. Otherwise, dimensional and precision issues may be encountered on the first production shift. 4. After the cutting fluid stock solution is added to the machine tool, it should not be left standing for a long time. When the machine tool is not in production, it is best to turn on the pump to circulate the cutting fluid for 30 minutes every day. 5. When adding cutting fluid in the production process, it must be added according to the proportion of use in the manual. Do not add only water without cutting fluid, otherwise it may cause the product to rust.
3. Why does the product rust quickly during processing? 1) The proportion of use is insufficient, and it is not added according to the proportion required by the manual. 2) The deterioration of the cutting fluid is manifested as: the pH value has dropped significantly, and there may be peculiar smell. To solve the problems in the use of cutting fluid, the easiest way is to dump all the original cutting fluid of the machine tool, clean it thoroughly, and then reconstitute and add it according to the proportion required by the manual.
