1. What is viscosity? It is the resistance of a fluid to flow. Its unit is mm²/s or centistoke (cSt), and it is expressed at a specific temperature. 2. What is viscosity index? It is a value that indicates the ability…
1. What is viscosity?
It is the resistance of a fluid to flow. Its unit is mm²/s or centistoke (cSt), and it is expressed at a specific temperature.
2. What is viscosity index?
It is a value that indicates the ability of oils to maintain their viscosity against temperature changes. In an oil with a high viscosity index, the viscosity changes less as the temperature rises and falls.
3. What is the basic purpose of lubrication?
To minimize friction between two metal surfaces.
4. What does NAS mean?
It is the test method that determines the distribution of micron-sized particles in oils (NAS cleanliness class). An increase in the number and size of particles in hydraulic oil causes serious failures in hydraulic valves.
5. What does T.A.N. (Total Acid Number) mean?
It provides information about the degree of oxidation of the oil. It is the most important parameter in determining the service life of the oil.
6. What is a coolant (emulsion)?
Coolants are cooling and lubricating products in which water and oil, two chemically distinct liquids, are blended homogeneously into a single product with the help of emulsifiers.
7. How many types of coolants are there?
Depending on the application and operation, coolants are divided into 3 types: mineral-based, semi-synthetic and synthetic.
8. What is EP (Extreme Pressure)?
EP additives are additives that react chemically with the metal surface to form a highly durable film on metal surfaces, positively enhancing the strength of the oil film.
9. What should be considered when preparing coolants (emulsions)?
The quality of the water used in the emulsion is important for the emulsion's service life. After the appropriate water and product have been selected, the machine to be filled must be chemically and physically cleaned. For the initial fill or top-ups, a proportional dosing pump should be used; if this is not possible, water should first be added to a separate tank and the product then added while mixing, and the machine should be filled only after a homogeneous mixture has been achieved. Thorough rinsing after cleaning reduces potential foaming problems.
10. What should be considered when using coolants (emulsions)?
Choosing the right product is the most important parameter. Values such as concentration, pH and conductivity should be checked periodically in emulsions. They should be used within the parameter ranges recommended by the manufacturer.
11. Why is tramp oil in coolants important?
Other oils that enter the system from slideway oils or for any other reason are known as tramp oil. The tramp oil content in the system should not exceed 3%. Otherwise:
• It accumulates on the surface of the emulsion, preventing the emulsion from being aerated (anaerobic conditions) and consequently causing bacterial growth in the emulsion.
• Smoke forms in the cutting zone.
• The stability of the emulsion deteriorates.
• The detergent properties of the emulsion decrease.
• The lubricating and cooling properties of the emulsion decrease.
• It circulates through the system with the emulsion and leaves sticky residues on machine components and workpieces. Skimming off the tramp oil that accumulates on the emulsion surface while the system is idle is very important for eliminating the harmful effects listed above.
12. Why does cutting tool life decrease in a machining center (CNC machines)?
Factors such as operating below or above the % concentrations recommended by an authorized technical team for the product suited to your process, excessive tramp oil contamination of the emulsion, and failure to use a suitable filter shorten the life of cutting tools over time.
13. Why do CNC machines rust?
Not using water within the parameters recommended for emulsions, low oil concentration, bacterial growth, and adding water directly into the machine are conditions that cause rust.
14. How can saw blade life be extended on metal cutting machines?
Saw blade life on metal cutting machines can be increased by using high cutting performance products (with EP additives).
15. What does PENETRATION mean?
It is a value that indicates the hardness or softness of a grease. It specifies the consistency of the grease (NLGI consistency). The penetration value should be selected based on information such as the rotational speed in the process, the lubrication method and interval, whether it operates under load and underwater, and the extent and values of temperature to which it is exposed.
16. Can greases containing different thickeners be mixed?
Greases containing different types of thickeners may be incompatible with one another, which can result in problems such as a breakdown in consistency and reduced performance. You can obtain information on the compatibility of grease types from our technical support team.
17. Can mineral-based greases and synthetic greases be applied to the same point?
Information on compatibility should be obtained before mixing mineral-based greases with synthetic greases. Even if they are compatible, mineral-based greases may adversely affect the performance of synthetic greases.
18. How often should maintenance oils be checked? (At what frequency should they be checked?)
In an ideal machine, they should be checked periodically every 3 months and monitored through trend analysis.
19. What is corrosion?
Corrosion is the change in the structure of metals as a result of reacting with oxidizing chemicals in their environment, such as oxygen.
20. How are metal parts machined on CNC machines using coolant protected from corrosion during waiting, packaging and storage?
To protect metal parts from corrosion, they must be coated with a rust preventive oil. The rust preventive oil should be selected in particular according to the condition of the machined material (wet or dry). If the material is wet, a water-displacing rust preventive oil must be used.
