Technical Field of the Invention

The present invention relates to a novel nozzle structure that is designed for minimum quantity lubrication (MQL) cooling processes implemented in machining operations, and that allows for utilizing the lubrication fluid at a minimum level by means of the high pulverization degree it provides.

State of the Art

Machining is a manufacturing method that involves shaping a machine element of which manufacturing process is determined through predesigning and pre-constructing operations, wherein the machine element is shaped by being subjected to cutting operations on worktables suitable for the respective manufacturing process by utilizing cutting tools. The manufacturing process that is carried out by removing small material (chip) pieces by using tools from the workpiece to be shaped is called machining. Machining is performed by creating tension on the workpiece through the relative motion of the cutting tool and/or the workpiece to one another.

The essential point of machining is that the tool and the workpiece feature different hardness characteristics. The tool is required to be harder than the workpiece. Thus, chips may be removed from the workpiece. Otherwise performing a proper machining process becomes impossible.

Machining allows for removing chips from materials, thereby enabling the production of parts in desired shapes and dimensions as well as the formation of various structures such as holes, screws, threads, canals, etc. on said parts. Processes performed on the workpiece are generally achieved through operations such as turning, milling, planing, shaping, grinding and honing.

Machining is a process of high complexity that is based on elastic and plastic deformation, and in which many different events such as friction, heat generation, chip breaking and contraction, work hardening that occurs on the machined workpiece and wearing of cutting edges are observed. Being a dynamic technology, machining requires reviewing many different types of technical field data including material, chemistry, static, heat, etc. throughout the process.

In machining processes, the material begins to yield following elastic and plastic deformations when the cutting tool is pressed onto the workpiece with a specific amount of force. A certain surface layer called a chip is removed from the workpiece once the intensity of the stress exceeds the fracture limit of the material. Several factors affect the process and accordingly should be taken into consideration during this process. These factors have impact on various crucial details including; how properly the machining process is performed, whether obtained products are of desired quality or not, whether the workpiece obtained as a result of the respective machining process features the required physical shape or not, what the expected physical life of both the cutting tool and the workpiece will be and how long the manufacturing process will take.

As one of two rigid structures shapes the other one physically by means of applying force in machining processes, one of the most crucial factors that should be taken into consideration is the heat generated and the effects thereof. A substantial amount of heat energy is generated during the machining process as two rigid structures are rubbed against one another through high- level forces. Almost the entirety of the mechanical energy exerted for performing the process converts to heat energy. The heat generated as a result may cause not only the cutting tool but also the workpiece to reach immensely high-temperature levels. The heat energy is required to be removed from both of these structures so as to ensure that the physical life of the cutting tool may remain long and that the workpiece that is being shaped may feature a proper physical structure. Concordantly, the cooling processes performed in machining operations are carried out at immensely high levels.

In the state of the art, cooling processes carried out in machining operations are generally subdivided into two groups as liquid cooling and air cooling. In air-cooled machining methods, both the cutting tool and the workpiece is cooled down with high- pressure air during the operation. In air-cooled processes, parameters such as surface smoothness which indicates the quality of the product are usually at desired levels as no material of solid or liquid nature come into contact with the tool and the workpiece. However, air cooling operations generally fail to satisfy during machining processes. The cutting tool and the workpiece of which temperatures rise constantly due to the heat energy generated at immensely high levels, cannot be cooled down at desired levels with high- pressure air.

The most common form of liquid cooling methods implemented in machining operations is the cooling processes performed with fluids containing boron oil-water mixture. In cooling methods in which said mixture is utilized, boron oil-water mixture is discharged on the cutting tool and the workpiece during the machining process. Therefore, both the workpiece obtained at the end of the process and the cutting tool which performs the cutting operation, end up being covered with boron oil-water mixture once the machining process is complete. Analogously, chips that emerge during the machining operation also become covered with said mixture. This prevents the machining process from being carried out in a clean manner. Moreover, high volumes of liquid waste are generated as a result of this operation.

Another cooling application implemented in order to reduce the amount of liquid waste generated in processes in which boron oil-water mixture is utilized, and to ensure that both the cutting tool and the workpiece become soiled at the lowest degree possible, is the application known as Minimum Quantity Lubrication (MQL) . Minimum Quantity Lubrication (MQL) technique which is commonly utilized in the state of the art, is a pulverized cooling method. In the Minimum Quantity Lubrication (MQL) technique, pulverized oil droplets are discharged onto the cutting tool and the workpiece. Therefore, no visible liquid is present when looking from outside. However, cooling is provided by means of covering the cutting tool and the workpiece with oil particles .

Minimum Quantity Lubrication (MQL) which features significant advantages when compared to boron oil-water mixtures, is used commonly in the state of the art. The pivotal point in the Minimum Quantity Lubrication (MQL) technique is the nozzle structure which pulverizes the oil and discharges it onto the cutting tool and the workpiece. Characteristics of the nozzle structure determine the degree and the quality of the pulverization process. Therefore, the nozzle structure used in the Minimum Quantity Lubrication (MQL) technique has great importance .

In general, the major problem of nozzle structures of Minimum Quantity Lubrication (MQL) systems used in the state of the art is that they cannot sufficiently reduce the size of the oil particles. As oil particles pulverized in said nozzle structures cannot be reduced to be in desired sizes, they are discharged onto the workpiece and to the cutting tool as large particles. This causes the process of discharging oil droplets to be performed in an irregular manner. Pulverized oil particles which are discharged in an irregular manner since they cannot be reduced to the desired size, become merged by getting into contact with one another. Merged oil droplets become larger in size and reach to their target in this manner. Thus, the oil consumption increases and the air-oil mixture discharged from the system becomes irregular. A homogeneous oil distribution cannot be achieved as oil particles remain large in size and since they become merged while being discharged from the system.

Nozzle structures in Minimum Quantity Lubrication (MQL) systems used in the state of the art do not offer any oil ratio adjustment features. The sole adjustment offered by the aforementioned structures is the on/off adjustment which allows for turning the oil discharging function on or off. Therefore, making instantaneous changes in the amount of oil that is being discharged is not possible in the respective system. This prevents performing any operation with regards to variable production requirements in manufacturing processes in which the Minimum Quantity Lubrication (MQL) system is implemented.

Minimum Quantity Lubrication (MQL) systems may operate between approximately 4-8 bars of pressure values due to the inadequacy present in the structures of nozzle configurations used in Minimum Quantity Lubrication (MQL) systems in the state of the art. The pulverization process cannot be performed correctly in case the pressure values exceed 8 bars and thus, Minimum Quantity Lubrication (MQL) systems cannot function properly.

Analogously, operating oil viscosity ratios which are used in Minimum Quantity Lubrication (MQL) systems in the state of the art, have a very narrow range. Generally, operating viscosity ratio in said systems are around 22-35 mm ² /s on average. This greatly reduces the diversity of oils that may be used in Minimum Quantity Lubrication (MQL) systems in the state of the art. Therefore, users are constrained to use the oil varietals that fall within the aforementioned operating viscosity range. Objects of the Invention

The object of the present invention is to ensure; better pulverization, minimal amount of oil consumption in cooling operations, adjustable oil, and airflow, minimal amount of oil waste generation at the end of cooling operations and homogeneous distribution of oil particles within the air by means of the nozzle developed to be used in Minimum Quantity Lubrication (MQL) system.

Another object of the present invention is to ensure that pulverized oil particles are discharged with constant quantity for an extended period of time by means of the nozzle developed to be used in Minimum Quantity Lubrication (MQL) system.

Yet another object of the present invention is to ensure that the nozzle may be used in more than one system, thereby allowing for taking advantage of the nozzle with maximum efficiency by means of the cover structure that will be used in Minimum Quantity Lubrication (MQL) system.

Description of the Figures FIGURE 1 illustrates the assembled view of the Minimum Quantity

Lubrication (MQL) system comprising the inventive nozzle structure incorporated therein.

FIGURE 2 illustrates the disassembled view of the Minimum

Quantity Lubrication (MQL) system comprising the inventive nozzle structure incorporated therein.

FIGURE 3 illustrates the portion that remains at the underside of the Minimum Quantity Lubrication (MQL) system.

FIGURE 4 illustrates the perspective view of the nozzle structure . FIGURE 5 illustrates the sectional view of the nozzle structure .

FIGURE 6 illustrates the top perspective view of the upper cover . FIGURE 7 illustrates the front perspective view of the upper cover without the upper surface.

FIGURE 8 illustrates the rear perspective view of the upper cover without the upper surface.

FIGURE 9 illustrates the bottom perspective view of the upper cover.

Components illustrated in the figures are enumerated individually and component names corresponding to these numbers are provided below, wherein:

1. Nozzle

2. Outer Block

3. Inner Block

4. Air Inlet Ducts

5. Acceleration Duct

6. Pulverization Area

7. Oil Canal

8. Dispersion Area

9. Upper Cover

10. Bolt Holes

11. Body

12. Oil Inlet Port 13. Main Suction Holes

14. Separation Layer

15. Lower Cover

16. Tube Sockets

17. Oil Tubes

18. Nozzle Seats

19. Fluid Canals

20. Air Receptacle

21. Air Distribution Canal

22. Small Ducts

23. Air Adjustment Connectors

24. Body Internal Pressure Canal

25. Internal Pressure Adjustment Connector

26. Mixture Outlet Hole

Detailed Description of the Invention The present invention relates to a novel nozzle (1) structure that is developed for Minimum Quantity Lubrication (MQL) systems utilized for cooling down the cutting tool and the workpiece properly in machining processes, that allows for homogeneously distributing highly fragmented oil particles within air by ensuring high-level pulverization, and that minimizes the amount of oil consumed for a cooling process. Moreover, a special Minimum Quantity Lubrication (MQL) system, as well as a special upper cover (9) incorporated therein, are designed for the purpose of utilizing the inventive nozzle (1) structure with maximum efficiency.

The inventive nozzle (1) comprises a special structure that enables high-degree disintegration of oil particles which become pulverized by passing therethrough by means of an inner structure thereof. A high-level pulverization process may be performed by means of the form created inside the inventive nozzle (1) structure and by the dimensions of the gap structure in which the pulverization process is performed.

The inventive nozzle (1) structure is illustrated in Figure 4. Figure 5 illustrates the side sectional view of the inventive nozzle (1) structure that basically comprises of two parts. The part that constitutes the outer portion of the inventive nozzle (1) structure is the outer block (2) . The inner block (3) constitutes the inner portion of the inventive nozzle (1) . Both structures feature a cylindrical shape. The inner block (3) is seated inside the outer block (2) structure, thereby forming the inventive nozzle (1) structure.

The high-level pulverization process performed by the inventive nozzle (1) structure is entirely ensured by means of the form created by interconnecting the inner block (3) and the outer block (2) structures. Gaps that are created as a result of interconnecting the outer block (2) and the inner block (3) ensure that high-level pulverization is achieved. Concordantly, air inlet ducts (4) are positioned on the side surface of the outer block (2) so as to be in a mutually relative position to each other. Said air inlet ducts (4) ensure that high-pressure air is conducted into the nozzle (1) .

Air conducted into the nozzle (1) through air inlet ducts (4), goes into the acceleration duct (5) located between the outer surface of the thin end that remains on the lower portion of the inner block (3) and the inner surface of the outer block (2) . Said acceleration duct (5) is in the form of a very narrow cylindrical cavity. The air that enters the nozzle (1) through the air inlet ducts (4), goes inside the acceleration duct (5) and accelerates by means of the high pressure generated therein due to the low volume of said acceleration duct (5) . The distance between the inner block (3) and the outer block (2) within the acceleration duct (5) may vary between 0.065 mm and 0.095 mm. The data obtained as a result of respective studies suggests that the optimal distance between the outer block (2) and the inner block (3) within the acceleration duct (5) should be 0.075 mm in order to achieve the ideal pulverization process. This value ensures that the best pulverization result is obtained. The length of the acceleration duct (5) is approximately 4 mm.

The air accelerated by passing through the acceleration duct (5) reaches to the pulverization area (6) that is positioned right below the thin end portion located at the underside of the inner block (3) structure. Pulverization area (6) is the region in which accelerated air and oil structure become mixed with one another and the high-level pulverization process is performed. The air that comes out of the acceleration duct (5) in a highly pressurized manner and goes into the pulverization area (6) having a much larger volume in comparison thereof and that creates low pressure, ensures that the vacuum effect is generated in the pulverization area. Oil flowing through the oil duct (7) located at the center of the inner block (3) is sucked into the pulverization area (6) by means of the vacuum effect produced therein. The oil vacuumed by means of the low pressure generated in the pulverization area (6) becomes disintegrated into small particles during the suction process.

The main element that enables high-level disintegration of the air vacuumed into the pulverization area (6) is the dimensions of the pulverization area (6) . The diameter of the pulverization area (6) which has a cylindrical form, may vary in a range between 2.73 mm and 2.79 mm. However, the data obtained as a result of the studies conducted in this regard indicates that the optimal diameter value should be 2.75 mm for the ideal pulverization process. When the diameter of the pulverization area (6) is arranged to be 2.75 mm, the sizes of the oil particles may be reduced to a minimum. The length of the pulverization area (6) may be in a range between 2.1 mm and 2.31 mm. However, the length value provided for the best pulverization process is determined as 2.21 mm as a result of the studies conducted in this regard. Therefore, the optimal length value for the length of the pulverization area (6) is 2.21 mm.

Air getting mixed with oil particles which become pulverized in the pulverization area (6) is dispersed in a dispersion area (8) that is located right below the pulverization area (6) and that features a progressively increasing diameter. The oil-air mixture is conducted to the dispersion area (8) by means of the pressure difference and begins to accumulate inside the body. As of this point, the oil-air mixture accumulated inside the main body may be discharged onto the cutting tool and the workpiece upon directing the operation of the system outwards. High-level cooling may be ensured for machining operations by means of oil particles which are homogeneously distributed inside the air as they are very well-pulverized.

Figure 1 illustrates the general view of the Minimum Quantity Lubrication (MQL) system designed to get maximum efficiency from the inventive nozzle (1) structure. The aforementioned Minimum Quantity Lubrication (MQL) system features a structure that allows for utilizing a plurality of the inventive nozzle (1) structure. The main element that enables utilizing a plurality of said nozzles (1) is the upper cover (9) structure that constitutes the upper portion of the Minimum Quantity Lubrication (MQL) system. Said upper cover (9) structure which has a square form in general, is positioned on the body (11) structure by means of the bolts inserted to the bolt holes (10) created so as to be in close proximity of regression points. An oil inlet port (12) which opens onto the gap located inside the body (11) is positioned on any location on the upper cover (9) structure. The main function of said oil inlet port (12) is to ensure that the oil which will accordingly be pulverized, enters the Minimum Quantity Lubrication (MQL) system. Said oil which is conducted into the body (11) through the oil inlet port (12), passes through the gaps located on the edges of the separation layer (14) which separates the body (11) into two portions, and is filled into the bottom portion of said separation layer (14) . Edges of said separation layer (14) do not completely come into contact with the inner surface of the body (11) and a small gap is located therebetween. Thus, the oil in liquid form may be contained inside the portion of the body (11) volume that remains under the separation layer (14) .

The liquid oil which is contained inside the portion that remains under the separation layer (14), passes through the main suction holes (13) located on the lower cover (15) and reaches to the tube sockets (16) . Liquid oil then reaches the oil tubes (17) by means of the tube sockets (16) wherein said oil tubes (17) extend so as to remain outside of the body (11) . While the lower ends of said oil tubes (17) are connected to the lower cover (15), upper ends thereof are connected to the upper cover (9) . The main reason behind connecting oil tubes (17) to the upper cover (9) is to ensure that liquid oil which is filled into the body (11), is conducted to nozzle (1) structures on the upper cover (9) for the purpose of being pulverized. Nozzle (1) structures are seated to the nozzle seats (18) located on the upper cover's (9) surface facing the inner portion of the body (11) . Connection points through which oil tubes (17) extending from the lower cover (15) to the upper cover (9) are connected to the upper cover (9) are the end portions of the fluid canals (19) extending to the nozzle (1) structures. Therefore, the liquid oil being conveyed through the oil tubes (17) may reach to the nozzle (1) structures by passing through the fluid canals (19) . Liquid oil which passes through the fluid canals (19), reaches to the open end portion that remains on the upper side of the oil canal (7) located inside the nozzle (1) structures.

Pressurized air which is another element that allows the functioning of the nozzle (1) structures, enters the Minimum Quantity Lubrication (MQL) system through the air receptacle (20) located on the upper cover (9) . Pressurized air which passes through the air receptacle (20), enters to an air distribution canal (21) . Said air distribution canal (21) ensures that the pressurized air contained therein is distributed to the nozzle (1) structures and to the body (11) . The air to be conducted to the nozzle (1) structures is conveyed to the nozzle (1) structures by means of small air ducts (22) extending between the air distribution canal (21) and nozzle seats (18) . The air that passes through the small air ducts (22) may reach to the air inlet ducts (4) located inside the nozzle (1) structures. However, said pressurized air is not conveyed to the nozzle (1) structure in an uncontrolled manner. Aforementioned control is performed by the air adjustment connectors (23) that are attached to the small air ducts (22) . An individual air adjustment connector (23) is available for each of the small air ducts (22) . Thus, the amount of pressurized air conveyed to the nozzle (1) structures may be adjusted by being controlled so as to have pressurized air at different amounts.

Air distribution canal (21) is connected to the gap structure inside the body (11) by means of a body internal pressure canal (24) . Therefore, pressurized air passing through the air distribution canal (21) may reach not only to the inside of the body (11) but also to the nozzle (1) structures. Thus, it is ensured that the body (11) is filled with pressurized air, thereby allowing for adjusting the internal pressure of the body (11) . An internal pressure adjustment connector (25) is positioned on the body internal pressure canal (24) in order to ensure that the internal pressure of the body (11) is adjusted properly. The amount of pressurized air to pass through the body internal pressure canal (24) may be adjusted by means of the internal pressure adjustment connector (25) . Thus, the internal pressure of the body (11) may be adjusted as desired.

Pulverized oil-air mixture obtained as a result of activating nozzle (1) structures is conveyed into the body (11) through the acceleration ducts (5) included inside the nozzles (1) . Nozzle

(I) structures that are placed into the nozzle seats (18) so as to ensure that end portions with acceleration ducts (5) extend into the body (11), store the pulverized oil-air mixture inside the body (11) in order to utilize it when necessary. Oil-air mixture conveyed into the body (11) is contained inside the body

(II) volume that remains above the separation layer (14) . Liquid oil stored in the lower portion of the body (11) and the pulverized oil-air mixture stored in the upper portion of the body may be preserved separately by means of the separation layer (14) .

Pulverized oil-air mixture that is contained inside the body (11) such that it remains in the upper portion of the separation layer (14), is taken out of the body (11) by means of the mixture outlet hole (26) located on any position on the upper cover (9), for the purpose of being conveyed to the part that will be cooled down. Fluid transmission system connected to the mixture outlet hole (26) may be designed based on user preference. The sole purpose of said transmission system is to convey the pulverized oil-air mixture to the part that will be cooled down.

The number of nozzle seats (18) on the aforementioned upper cover (9) structure may vary. It should be noted that the number of nozzle seats (18) on the upper cover (9) has to correspond to the number of tube sockets (16), the number of oil tubes (17), the number of fluid canals (19), the number of small air ducts (22) and to the number of air adjustment connectors (23) . As each nozzle (1) structure is controlled independently and are operated to such that they function with different performances. Individual auxiliary elements are required for each nozzle (1) as all of the auxiliary elements that ensure the operation of the nozzle (1) structures are independent of each other. Therefore, the number of nozzle seats (18) on the upper cover (9) structure is equal to the number of auxiliary elements connected thereto.

The number of nozzle seats (18) on the upper cover (9) can be determined based on the user preferences and the design of the upper cover (9) may be arranged accordingly. Therefore, nozzle (1) structures may be provided in a desired number for the sufficiency of the pulverized oil-air mixture to be created. Utilizing all of the nozzles (1) is not compulsory in case the number of nozzles (1) exceeds the quantity that is necessary for the cooling process to be performed. Fewer nozzle (1) structures may be operated such that the unnecessary nozzles (1) remain inactive. Upper cover (9) structure comprising 3 nozzle seats (18) may be seen in Figure 6, Figure 7, Figure 8 and Figure 9. It was observed that Minimum Quantity Lubrication (MQL) systems comprising three of the inventive nozzle (1) structures deliver high performance, and provide pulverization at immensely high levels by consuming the minimum amount of oil as a result of the studies and respective tests conducted in this regard.

Cooling processes implemented in machining operations become much more efficient by means of the inventive nozzle (1) structure. A top tier cooling process is achieved during the operation because of the fact that oil particles that are densely pulverized within the air, are disintegrated substantially. Since oil particles are reduced in size to a great extent, oil particle consumption is maintained at the minimum level, thereby obtaining an air-oil mixture in which oil particles are distributed homogeneously. Thus, the quantity of oil consumed for the cooling process is decreased to minimum level. This also allows for substantially reducing the amount of waste oil generated at the end of the cooling process.

Oiling levels of both the workpiece obtained as a result of the cooling process performed by means of the inventive nozzle (1) structure and the cutting tool performing the cutting operation are also decreased to a minimum. Analogously, minute amount of oil adheres to chips removed as a result of the machining process. This allows for not only shortening the duration of the cleaning operation to be performed at the end of the machining process but also for releasing much less pollutants to the environment during the process. Moreover, since there is much less amount of oil to be cleansed from the chip, the amount of energy to be exerted for this process is reduced for the sake of preventing the environmental pollution.