Cutting fluid is widely used in cutting processing due to its functions of cooling, lubricating, cleaning and rust prevention. During the use of cutting fluid, problems such as deterioration, odor, corrosion, foaming, and skin allergies of the operators often occur. The following combines our actual work experience to talk about the problems and countermeasures in the use of cutting fluid.
The problem of cutting deterioration and odor
The main reason for the deterioration and odor of the cutting fluid is that the cutting fluid contains a large number of bacteria, and the bacteria in the cutting fluid mainly include aerobic bacteria and anaerobic bacteria. Aerobic bacteria live in an environment with minerals, such as water, cutting fluid concentrate, and oil leaked from machine tools. Under aerobic conditions, they split into two every 20 to 30 minutes. Anaerobic bacteria live in an environment without oxygen, split into two every hour, and release SO2 from metabolism, which smells like 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:
Bacteria invade during the preparation process, such as bacteria in the water for preparing cutting fluid.
Bacteria in the air get into the cutting fluid.
The transfer between workpiece processes causes infection of cutting fluid.
Bad habits of the operator, such as littering dirty things.
Poor cleanliness of machine tools and workshops.
(2) Methods of controlling bacterial growth
Use high-quality, stable cutting fluid.
Using pure water to prepare concentrated solution is not only easy to prepare, but also can improve the lubricity of cutting fluid, reduce the amount taken away by chips, and prevent bacterial erosion.
When using, it is necessary to control the ratio of the concentrated liquid in the cutting fluid not to be too low, otherwise it is easy to cause bacteria to grow.
Since the oil used in the machine tool contains bacteria, it is necessary to minimize the oil leaked from the machine tool from mixing with the cutting fluid.
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 increase the pH value.
Keep the cutting fluid clean, and do not let the cutting fluid come into contact with dirty oil, food, tobacco and other dirt.
Frequent use of fungicides. Click to receive 10G CNC programming tutorial for free
Keep the workshop and machine tools clean.
If the equipment does not have a filter device, the floating oil should be skimmed regularly to remove the dirt.
The problem of cutting fluid corrosion
(1) Causes of corrosion
The proportion of concentrated liquid in cutting fluid is low.
The pH of the cutting fluid is too high or too low. For example, when PH>9.2, it will corrode aluminum. Therefore, an appropriate pH value should be selected according to the metal material.
Contact of dissimilar metallic materials.
Place the workpiece on a paper or wood pad.
Parts are stacked.
The number of bacteria in the cutting fluid exceeds the standard.
The humidity in the working environment is too high.
(2) Methods of preventing corrosion
The cutting fluid is prepared with pure water, and the ratio of the cutting fluid should be used according to the recommended value in the cutting fluid manual.
If necessary, use a rust preventive fluid.
Control the number of bacteria and avoid the production of bacteria.
Check the humidity, and pay attention to controlling the humidity of the working environment within an appropriate range.
To avoid contamination of cutting fluid.
Avoid contact with dissimilar materials, such as aluminum and steel, cast iron (including magnesium) and copper.
