Cutting fluid in the use of problems and countermeasures
Cutting fluid is widely used in cutting because of its functions of cooling, lubrication, cleaning and rust prevention. Cutting fluid often appears in the use of deterioration, corrosion, foam, the use of operator skin allergies and other problems, the following combined with our practical experience in the work, talk about the use of cutting fluid problems and countermeasures.
First, the problem of cutting wave deterioration and odor
The main reason for the deterioration of the cutting fluid is that the cutting fluid contains a large number of bacteria, and the bacteria in the cutting fluid are mainly aerobic bacteria and anaerobic bacteria. Aerobic bacteria live in a mineral environment, such as water, cutting fluid concentrate and machine tool leakage of oil, under aerobic conditions, every 20 to 30 minutes split into two. The anaerobic bacteria live in an environment without oxygen, divide into two every hour, metabolize and release SO2, smell rotten eggs, and the cutting fluid turns black. When the bacteria in the cutting fluid is greater than 106, the cutting fluid will become smelly.
(1) Bacteria enter the cutting fluid mainly through the following channels:
1) Bacteria invade in the preparation process, such as bacteria in the water preparing the cutting fluid.
2) Bacteria in the air enter the cutting fluid.
3) The transfer of workpiece between processes causes the infection of cutting fluid.
4) The operator's bad habits, such as littering dirty things.
5) Poor cleanliness of machine tools and workshops.
(2) Methods for controlling bacterial growth
1) Use high quality and good stability cutting fluid.
2) The preparation of concentrated liquid with pure water is not only easy to prepare, but also can improve the lubrication of the cutting fluid, and reduce the amount of chips taken away, and can prevent bacterial erosion.
3) When used, the ratio of concentrated liquid in the cutting fluid should not be too low, otherwise it is easy to make bacteria grow.
4) Because the oil of the machine tool contains bacteria, it is necessary to reduce the oil from the machine tool as much as possible to mix with the cutting fluid.
5) When the pH value of the cutting fluid is 8.3 ~ 9.2, it is difficult for bacteria to survive, so new cutting fluid should be added in time to improve the pH value.
6) Keep the cutting fluid clean, do not make the cutting fluid contact with dirty oil, food, tobacco and other dirt.
7) Use fungicides regularly.
8) Keep the workshop and machine clean.
9) If the equipment does not have a filter device, the oil slick should be regularly skimmed and the dirt removed.
Second, the corrosion of cutting fluid
(1) Cause of corrosion
1) The proportion of concentrated liquid in cutting fluid is low.
2) The pH value of the cutting fluid is too high or too low. For example, when the PH is greater than 9.2, aluminum is corroded. Therefore, the appropriate pH value should be selected according to the metal material.
3) Dissimilar metal material contact.
4) Paper or wood cushion the workpieces.
5) Stacking of parts.
6) The number of bacteria in the cutting fluid exceeds the standard.
7) The working environment humidity is too high.
(2) Methods for preventing and controlling corrosion
1) Prepare cutting fluid with pure water, and the proportion of cutting fluid should be used according to the recommended value in the cutting fluid manual.
2) If necessary, use anti-rust solution.
3) Control the number of bacteria to avoid the production of bacteria.
4) Check the humidity, pay attention to control the humidity of the working environment in the appropriate range.
5) To avoid cutting fluid contamination.
6) To avoid contact with dissimilar materials, such as aluminum and steel, cast iron (containing magnesium) and copper.
Third, the problem of bubbles
When using cutting fluid, sometimes the surface of the cutting fluid will produce a lot of foam.
(1) The main causes of bubbles
1) The liquid level of cutting fluid is too low.
2) The flow rate of the cutting fluid is too fast, and the bubbles have no time to overflow, accumulating more and more, resulting in a large number of bubbles.
3) Too many right angles in the sink design, or the nozzle Angle of the cutting fluid is too straight.
(2) Methods for avoiding bubbles
1) In the centralized cooling system, the pipeline is graded in series, and the pipeline pressure near the cooling box should be lower.
2) Ensure that the liquid level of the cutting fluid is not too low, check the height of the liquid level in time, and add the cutting fluid in time.
3) Control the flow rate of cutting fluid not too fast.
4) When designing the sink, it should be noted that the sink right Angle should not be too much.
5) When using cutting fluid, pay attention to the cutting fluid nozzle Angle should not be too straight.
Fourth, the operator's skin allergy problem
(1) The main cause of the operator's skin allergy
1) The pH value is too high.
2) Composition of cutting fluid.
3) Insoluble metal and oil used in machine tools.
4) The proportion of concentrated liquid is too high.
5) The protective suspension layer on the surface of the cutting fluid, such as the odor sealing layer and the anti-foam layer. Bactericides and unclean cutting fluids.
(2) At work, in order to avoid skin allergies of the operator, the following points should be noted
1) The operator should apply protective oil, wear overalls and gloves, and pay attention to avoid direct contact between the skin and the cutting fluid.
2) The proportion of concentrated liquid in the cutting fluid must be used in accordance with the recommended value of the cutting fluid.
3) Use fungicides according to the dosage in the instructions.
In addition, fluorine rubber and grease rubber are less deformed by cutting fluid, and can be given priority when used as machine tool seals. In order to prevent deformation, the grease content of rubber used in machine seals should generally be greater than 35%. In addition, in order to effectively prevent the cutting fluid caused by the paint off the machine tool, you can choose epoxy resin paint or polycavity ester paint.
In short, the use of cutting fluid in normal production, if you can pay attention to the above problems, you can avoid unnecessary economic losses, effectively improve production efficiency.
