Problems and countermeasures of cutting fluid deterioration and smell

The main reason for the deterioration and smell of cutting fluid is that the cutting fluid contains a lot of bacteria. The bacteria in the cutting fluid mainly include aerobic bacteria and anaerobes. Aerobic bacteria live in environments with minerals, such as water, concentrated fluid of cutting fluid, and oil leaked from machine tools. Under aerobic conditions, they split into two every 20-30 minutes. The anaerobic bacteria live in an environment without oxygen, split into two per hour, metabolize and release SO2, smell of 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 during the preparation process, such as bacteria in the water used to prepare the cutting fluid.

2) Bacteria in the air enter the cutting fluid.

3) The transfer of workpieces between processes causes infection of cutting fluid.

4) Bad habits of the operator, such as littering.

5) The cleanliness of the machine tool and workshop is poor.

2. Methods of controlling bacterial growth

1) Use high-quality, stable cutting fluid.

2) Using pure water to prepare a concentrated solution is not only easy to prepare, but also can improve the lubricity of the cutting fluid, reduce the amount of chips carried away, and prevent bacterial erosion.

3) When using, it is necessary to control the ratio of concentrated liquid in the cutting fluid not to be too low, otherwise it is easy to cause bacteria to grow.

4) Since the oil used by the machine tool contains bacteria, it is necessary to minimize the oil leaking from the machine tool mixing into the cutting fluid.

5) When the pH of the cutting fluid is between 8.3 and 9.2, it is difficult for bacteria to survive, so new cutting fluid should be added in time to increase the pH.

6) Keep the cutting fluid clean, and don't let the cutting fluid come into contact with dirt, oil, food, tobacco, etc.

7) Bactericides are often used.

8) Keep the workshop and machine tools clean.

9) If the equipment does not have a filtering device, the oil slick should be skimmed regularly to remove dirt.