Cutting fluid is widely used in cutting because of its functions of cooling, lubrication, cleaning and rust prevention. The cutting fluid deterioration smelly and corrosion, produce foam, skin allergies and other often use the operator in use, the combination of practical experience in our work, talk about cutting fluid problems and Countermeasures in application.
First, the problem of deterioration and odor of cutting wave
The main reason for the deterioration of cutting fluid is that the cutting fluid contains a large number of bacteria, and the bacteria in the cutting fluid are mainly oxygen consuming bacteria and anaerobic bacteria. Oxygen consuming bacteria live in a mineral environment, such as water, cutting fluid concentrate and oil leaking from the machine tool. Under aerobic conditions, it splits to two every 20 to 30min. And anaerobic bacteria in the presence of oxygen free environment, split into two per hour, metabolic release of SO2, smell of rotten eggs, cutting fluid black. When the bacteria in the cutting fluid is greater than 106, the cutting fluid will stink.
(1) bacteria enter the cutting fluid mainly through the following channels:
1) bacterial invasion in the preparation process, such as the preparation of cutting fluid bacteria in the water.
2) bacteria in the air enter the cutting fluid.
3) the transport of workpiece between processes leads to the infection of cutting fluid.
4) bad habits of operators, such as throwing dirty things.
5) poor cleanliness of machine tools and workshops.
(2) the method of controlling bacterial growth
1) using high quality and stable cutting fluid.
2) the preparation of concentrated solution with pure water is not only easy to prepare, but also can improve the lubricity of cutting fluid, reduce the amount of chip removed, and prevent bacterial erosion.
3) when using, the ratio of concentrated liquid in cutting fluid should not be too low, otherwise it will make bacteria grow easily.
4) because the oil used in the machine tool contains bacteria, it is necessary to reduce the oil leakage from the machine tool into the cutting fluid as much as possible.
5) when the pH value of cutting fluid is between 8.3 and 9.2, it is difficult for bacteria to survive. Therefore, new cutting fluid should be added in time to increase pH value.
6) keep the cutting fluid clean, do not make the cutting fluid contact with dirty oil, food, tobacco and other dirt.
7) regular use of fungicides.
8) keep workshop and machine tool clean.
9) if the equipment does not have the filter device, should periodically skim off the oil spill, remove the dirt.
Two. Corrosion of cutting fluid
(1) the cause of corrosion
1) the proportion of concentrated liquid in cutting fluid is low.
2) the pH value of cutting fluid is too high or too low. For example, PH > 9.2, corrosion of aluminum. Therefore, the appropriate pH value should be chosen according to the metal material.
3) dissimilar metal contact.
4) putting pieces of paper or wood mats.
5) spare parts stacking.
6) the amount of bacteria in cutting fluid is over standard.
7) the humidity is too high in the working environment.
(2) the method of corrosion prevention
1) using pure water to prepare cutting fluid, and the proportion of cutting fluid should be used according to the recommended value of the cutting fluid instructions.
2) use rust preventive liquid in case of need.
3) control the number of bacteria to avoid the emergence of bacteria.
4) check the humidity, pay attention to control the humidity of the working environment in the appropriate range.
5) avoid cutting fluid contamination.
6) avoid dissimilar material contact, such as aluminum and steel, cast iron (containing magnesium) and copper.
Three, the problem of foam
In the use of cutting fluid, sometimes the cutting fluid surface will produce a large number of foam.
(1) the main cause of foam formation
1) the liquid level of the cutting fluid is too low.
2) the flow velocity of the cutting fluid is too fast, the bubbles have no time to overflow, and the more bubbles accumulate, leading to a large number of bubbles.
3) there are too many right angles in the design of the flume, or the nozzle angle of the cutting fluid is too straight.
(2) avoid foaming
1) in the centralized cooling system, the pipeline is divided into series, and the pipeline pressure near the cooling box should be lower.
2) ensure that the liquid level of cutting fluid is not too low, check the liquid level in time, and add cutting fluid in time.
3) do not control the flow rate of cutting fluid too quickly.
4) in the design of flume, we should pay attention to the right angle of the flume is not too much.
5) the use of cutting fluid should pay attention to the cutting fluid nozzle angle is not too straight.
Four, operator skin allergy problems
(1) the main cause of operator skin allergy
1) the pH value is too high.
2) the composition of cutting fluid.
3) insoluble metals and oil used in machine tools.
4) the use ratio of concentrated liquid is too high.
5) the protective suspension layer on the surface of cutting fluid, such as odor sealing layer and anti foam layer. Fungicides and clean cutting fluids.
(2) in the work, in order to avoid the operator skin allergy, should pay attention to the following several points
1) the operator should protect the oil, wear overalls, gloves, should pay attention to avoid skin and cutting fluid direct contact.
2) the proportion of concentrated liquid in cutting fluid must be used according to the recommended value of cutting fluid.
3) the use of fungicides should be used according to the dosage in the instructions.
In addition, the fluorine rubber and the fat rubber are affected by the cutting fluid and have little deformation, and they can be taken as the priority when they are used as the sealing parts of the machine tools. In order to prevent deformation, the amount of grease used in the sealing parts of machine tools should generally be greater than 35%. In addition, in order to effectively prevent the cutting fluid caused by the machine tool paint off, you can choose epoxy resin or poly cavity ester paint.
In short, the use of cutting fluid in normal production, if you can pay attention to the above problems, can avoid unnecessary economic losses, and effectively improve production efficiency.
