The primary signs of bacterial growth in metalworking fluids are the onset of spoilage, which typically follows this sequence: a slight foul odor → appearance turns gray-brown → pH value continuously drops → rust prevention properties deteriorate → the emulsion breaks down and separates, with oil floating on the surface → cutting performance declines → significant sludge formation, leading to clogged filtration equipment → release of hydrogen sulfide gas, worsening air quality in the workshop.
Video | "Look, Smell, Ask, and Feel" Diagnosis of Bacterial Growth in Metalworking Fluids
Mild Cases: Opt for "Treatment"
If testing reveals bacterial colony counts reaching 10³ CFU/ml or mold counts at 10¹ CFU/ml or higher, the fluid can be classified as being in a bacterial growth state. In such cases, it is crucial for the company to pay attention and make timely adjustments.
Problem Resolution: Treating the Issue with "Medicine"
1. Add Biocides and pH Adjusters: Introduce biocides and pH adjusters to treat the fluid in the tank, aiming to curb bacterial growth and restore balance.
2. Eliminate Sources of Bacteria: Take steps to eliminate sources of contamination, such as cleaning up stray oils, sludge, and other debris in the work area.
3. Increase Concentration: Enhance the concentration of the cutting fluid to strengthen its resistance against bacterial contamination.
4. Improve Usage Habits: Encourage better practices in handling and using cutting fluids, including regular maintenance and proper fluid management.
5. Maintenance During Downtime: Ensure that proper maintenance is conducted during machine shutdowns or holiday periods to prevent bacterial proliferation.
Severe Cases: Opt for "Tank Replacement"
If the bacterial colony count reaches 10⁵ CFU/ml or mold count exceeds 10³ CFU/ml, it is recommended that the company replace the tank fluid entirely. When replacing the fluid, it's important to thoroughly clean and remove bacterial colonies from hidden areas such as machine tool pipelines. If this step is overlooked, the fresh metalworking fluid introduced after the tank replacement may quickly become contaminated, leading to a rapid resurgence of bacterial growth and resulting in another instance of fluid spoilage.
Correct Tank Replacement Procedure
To ensure a successful tank replacement, follow these steps:
1. Thoroughly Clean the Tank Fluid: Remove the existing fluid completely.
2. Remove Chips and Bacterial Slime: Clean the sides and bottom of the tank to eliminate metal chips and bacterial slime.
3. Clean with Low-Concentration Metalworking Fluid and Biocide: Use a low-concentration metalworking fluid mixed with a biocide to wash the tank thoroughly, then drain the cleaning fluid.
4. Prepare and Refill with Fresh Fluid: Finally, mix and refill the tank with fresh metalworking fluid for use.
It's worth noting that manually cleaning the small chips and sludge from the machine tool tank can be time-consuming and labor-intensive. Switching to a quick tank replacement system can significantly improve work efficiency and enhance the worker's experience. For instance, the Kerun KR-ETC300B split-type quick tank cleaning machine offers thorough cleaning, safety, environmental friendliness, and ease of operation. This equipment can handle fluid suction at a rate of 200L per minute and a discharge rate of 2000L per hour, allowing simultaneous fluid suction and discharge. Additionally, the device is equipped with an ozone sterilization function, effectively aiding companies in maintaining and cleaning their machine tool metalworking fluid tanks, making fluid maintenance a more efficient and convenient task.
Figure|Kerun KR-ETC300B split-type quick tank cleaning machine
Image | Improving the Workplace Environment (Stray Oil, Sludge, etc.)
Want to Avoid Bacterial Growth? Keep Reading↓↓↓
Summer is the peak season for bacterial growth in metalworking fluids. Here's a friendly reminder from Kerun: Make sure to prevent this by ① precisely managing pH levels; ② carefully controlling fluid concentration; and ③ maintaining a clean and organized work environment!
In case of machine downtime, remember to regularly circulate the fluid to avoid it staying in an anaerobic state for too long. For short-term shutdowns, consider increasing the fluid concentration by 2-3% before stopping. For longer-term shutdowns, it is recommended to transfer the tank fluid to another machine for use.
Kerun is dedicated to becoming a leader in green industrial fluids, using advanced technology to support high-end manufacturing.
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