A localized minimum quantity lubrication system for cutting tools

Abstract

Described is a localized Minimum Quantity Lubrication (MQL) system (100) for cutting tools to provide efficient lubrication in the form of aerosol The system (100), including an MQL unit (102) and a MQL control unit (103), combines compressed air, vegetable-based lubricant, and user-defined parameters to generate a finely controlled aerosol. Key components include pneumatic circuits for air regulation, a dosing unit (120) for precise lubricant delivery, and an aerosol generator and booster (404) for creating and boosting the mixture of oil and air in the form of aerosol. The system (100) ensures minimal lubricant consumption while enhancing cutting tool performance, reducing friction, and improving operational efficiency. Additionally, it offers configurable modes, advanced feedback mechanisms through sensors, and eco-friendly operation, making it a sustainable and cost-effective alternative to traditional coolants delivery methods.

Description

[0001] A LOCALIZED MINIMUM QUANTITY LUBRICATION SYSTEM FOR CUTTING TOOLS

[0002] FIELD OF THE INVENTION:

[0003] The present invention relates to minimum quantity lubrication system as a necessary accessory for machine tools. More particularly relates to controlled localised minimum quantity lubrication system for cutting tools.

[0004] BACKGROUND OF THE INVENTION:

[0005] In the field of modem metalworking, machining processes such as cutting, shaping, and forming play a pivotal role in manufacturing. These processes involve the removal or modification of material from a workpiece using specialized cutting tools. However, one of the inherent challenges in these operations is the substantial amount of heat generated at the interface between the cutting tool and the workpiece. This heat arises primarily due to friction and deformation caused by the high-speed interaction between the tool and the metal surface. The excessive heat buildup not only affects the quality of the finished product but also impacts the longevity and performance of the cutting tools.

[0006] Traditionally, mineral oil or water-based flood coolant systems are employed to address this issue. These coolants, typically composed of a mixture of mineral oil / synthetic oil and water, are sprayed or flooded over the workpiece and the cutting tool to dissipate heat. However, these coolants primarily act as cooling agents rather than effective lubricants. While they may succeed in lowering the temperature to some degree, they fail to provide the necessary lubrication at the point of contact between the tool and the workpiece. The lack of proper lubrication leads to increased friction, which in turn contributes to the generation of additional heat. This creates a vicious cycle where the cutting tool is continuously subjected to high temperatures and wear, ultimately reducing its operational lifespan.

[0007] In metal cutting operations, the cycle of rapid heating during cutting followed by cooling when the process pauses or slows down creates severe thermal stress on both the workpiece and the cutting tool. The sudden temperature fluctuations can weaken the structural integrity of the workpiece, resulting in deformations or warping. Additionally, the cutting tool itself is prone to damage as repeated exposure to high temperatures followed by cooling can lead to the development of microscopic cracks and fractures. Over time, these micro-damages accumulate, drastically shortening the tool's lifespan and requiring frequent replacements, which increases operational costs.

[0008] The traditional method of using flood coolant systems is widespread across various machining tools, including manual lathes, milling machines, saws, and CNC machining centres. However, this system has several disadvantages. Flood coolants, often mineral / synthetic oil-based, are not eco-friendly and provide limited lubrication at the cutting interface. Moreover, they do not offer precision cooling, as the fluid is not delivered directly to the point of cutting, resulting in suboptimal cooling and reduced tool life.

[0009] Additionally, these coolant systems require extensive maintenance. The coolant must be continuously filtered and monitored, as it evaporates over time and is carried away by metal chips during the machining process. This leads to the need for regular replacement, typically every one to two months. The disposal of spent coolant presents an environmental hazard, as it is classified as hazardous waste. Recycling and disposal further complicate operational logistics and raise concerns about environmental sustainability.

[0010] Maintaining the proper pH level and concentration of mineral oil in coolant is both labor-intensive and costly, impacting the quality of the machined parts and the longevity of the tools. The periodic maintenance of traditional flood coolant systems increases operational costs, while the waste generated poses a significant threat to the environment.

[0011] Existing solutions in the art, such as those disclosed in British Patent GB2212078A and U.S. Patent US7625157B2, describe systems where coolant is delivered to the tool via internal passages or inlets. However, these systems fail to address the inefficiencies in coolant delivery. In particular, they lack the precision and controlled localization necessary to optimize fluid application at the cutting edge. Excessive fluid consumption, along with increased maintenance requirements, further complicates their effectiveness. It is worthwhile to note that the existing solutions in the art require external booster as a source of air supply to the system that increases the cost of the equipment.

[0012] The Japanese Patent Application JP2006249369A to Satoshi Suda, et al; relates to a lubricant for metal working by supplying extremely small amount of lubricant. This application includes an oil agent with an alicyclic polycarboxylic acid ester compound. However, this patent application discloses only a lubricant and not a system that enhances localized minimum quantity lubrication dose to the cutting tool with variable pressure. Also, it is noted that this citation fails to teach delivery of aerosols as a form of lubricant. Further, the disclosed lubricant may not be compatible to all kinds of cutting tools and other systems.

[0013] The Chinese Patent CN107803702A to Xiong Weiqiang, et al; relates to a lubricating and cooling method and system of processing center machine tool that includes a machine tool with a jet pipe that dispenses lubricant. However, high amount of lubricant is utilized in this type of mechanism, leading to wastage and increased maintenance.

[0014] Accordingly, there is need of a localized cooling system for cutting tools to enhance localization of minimum quantity lubrication dose to the cutting tool by adjusting variable pressure from the booster to reduce fluid consumption. There is also need of the localized minimum quantity lubrication system for cutting tools to significantly reduce periodic maintenance and cleaning of machine tools.

[0015] SUMMARY

[0016] The present invention relates to a Localized Minimum Quantity Lubrication (MQL) System for discharging a controlled and precise amount of lubrication in the form of a pressurized aerosol directly to a cutting tool or in a cutting zone. The system enhances machining efficiency by reducing lubricant consumption, improving cutting tool life, and ensuring effective lubrication and chip evacuation. The Localized Minimum Quantity Lubrication (MQL) System includes an MQL unit that is removably positionable on a platform like a table, a MQL control unit for providing inputs to the system, and an output unit delivering the pressurized aerosol to a cutting tool. The an MQL unit is permanently installable on a machine tool as well.

[0017] The MQL unit includes an air unit configured to supply compressed air, a pneumatic control unit adapted to regulate the compressed air into at least two pneumatic circuits, a reservoir configured to supply oil, a dosing unit operable to receive compressed air and oil and to generate metered doses of pressurized oil, an aerosol generator and booster (AGB) unit configured to receive the metered doses of oil and regulated air, mix the oil and air, and generate a pressurized aerosol, and an MQL discharge unit configured to receive the pressurized aerosol from the AGB unit and deliver it to an output unit.

[0018] The MQL control unit includes an input-display panel configured to receive user- defined parameters and display operational data, and a manual control panel operable to enable operation in either an automatic mode or a manual mode. The control unit is further coupled to an output unit configured to deliver the pressurized aerosol to a cutting tool. The air unit includes an input tube adapted to receive compressed air from an external source, a water separator for removing moisture from the compressed air, an input valve for regulating the flow of compressed air, and a pressure regulator configured to maintain the compressed air within a range of 4 bar to 10 bar.

[0019] The pneumatic control unit includes a first pneumatic circuit (CTK1) configured to supply pressurized air to the dosing unit and a second pneumatic circuit (CTK2) configured to supply regulated air to the aerosol generator and booster (AGB) unit. The pneumatic control unit further includes a first regulator and a valve for controlling the first pneumatic circuit (CTK1), a second regulator and a valve for controlling the second pneumatic circuit (CTK2), as well as pressure sensors and switches adapted to monitor and control the air pressure within the circuits.

[0020] The dosing unit has an air cylinder that is operable to drive a high-pressure pump, a dosing injector configured to deliver precise doses of pressurized oil, and a block housing the air cylinder, the pump, and the injector. The dosing unit is further equipped with an inlet tube connected to the reservoir and incorporating a nonreturn valve, and a discharge tube also incorporating a non-return valve for delivering pressurized oil to the AGB unit.

[0021] The aerosol generator and booster (AGB) unit include a mixer configured to combine oil doses with regulated air to form a mixture, a booster adapted to convert the mixture into a pressurized aerosol using an adiabatic process, and a motor- driven mechanism operable to power the booster.

[0022] The MQL discharge unit includes a pressure sensor providing real-time pressure feedback to a programmable logic controller (PLC), a pressure gauge configured to monitor output pressure, and a third switch operable to prevent overpressure conditions. The programmable logic controller (PLC) of the MQL Unit is configured to manage operational parameters, a human-machine interface (HMI) enabling mode selection and parameter adjustments, and alarm systems adapted to indicate abnormal operating conditions that can be interfaced with the machine tool. The output unit is replaceable and configurable to deliver the aerosol either through a spindle to the cutting tool or via an external nozzle to the cutting zone. The system is operable in two modes: a first automatic mode and a second manual mode. The automatic mode further includes a continuous cycle mode for delivering a constant aerosol and an interrupted cycle mode for periodic aerosol delivery with increased pressure to facilitate chip evacuation. The lubricant used in the system is a biodegradable, non-hazardous, vegetable-based oil.

[0023] The invention provides a method for operating a Localized Minimum Quantity Lubrication (MQL) System to deliver a precise aerosolized lubricant directly to a cutting tool. The method involves supplying compressed air to an air unit, regulating the air into at least two pneumatic circuits, and delivering oil from a reservoir to a dosing unit where metered doses of pressurized oil are generated. The pressurized oil is mixed with regulated air in an aerosol generator and booster (AGB) unit to create an aerosol, which is further boosted in pressure. The resulting pressurized aerosol is then delivered through a configurable output unit to the cutting tool, ensuring efficient lubrication and enhanced machining performance. The system and method of the present invention optimizes lubrication efficiency, enhances machining accuracy, and supports sustainable manufacturing practices.

[0024] BRIEF DESCRIPTION OF DRAWINGS: The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein,

[0025] FIG. 1 shows a front perspective view of a localized minimum quantity lubrication system of the present invention;

[0026] FIG. 2 shows a front view of a MQL (Minimum Quantity Lubrication) unit of system of FIG. 1;

[0027] FIG. 3 shows a front view of the air unit of system of FIG. 1;

[0028] FIG. 3 A shows a front view of a pneumatic control unit of the system of FIG. 1; FIG. 3B shows a schematic of the pneumatic control unit of the system of FIG. 4A;

[0029] FIG. 4 shows a front view of the AGB unit of system of FIG. 1;

[0030] FIG. 5 shows the dosing unit 120 of the system of FIG. 1;

[0031] FIG. 6 shows the MQL discharge unit 128 of the system of FIG. 1;

[0032] FIG. 7 shows a schematic view of the system of FIG. 1; FIG. 8 a process flow diagram of the system 100 of FIG. 1; and

[0033] FIGS. 9A, 9B and 9C shows the flow charts showing steps in the configuring a PLC of the system of FIG. 1.

[0034] DESCRIPTION OF THE INVENTION: References in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

[0035] References in the specification to “preferred embodiment” means that a particular feature, structure, characteristic, or function described in detail thereby omitting known constructions and functions for clear description of the present invention.

[0036] The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed and obviously many modifications and variations are possible in light of the above teaching.

[0037] Referring to FIG. 1, the system 100 illustrates a localized Minimum Quantity Lubrication (MQL) system for a cutting tool. This system, hereinafter referred to as the system 100, delivers a controlled and precise amount of lubrication in the form of aerosol directly to the cutting tool. The system 100 is preferably removably positionable on a platform 101 such as a table with wheels or like that. The system 100 includes an MQL unit 102 and an MQL control unit 103. The MQL unit 102 includes a plurality of components such as an air unit 104, a pneumatic control unit 112, and a reservoir 116. Additionally, the MQL unit 102 includes a dosing unit 120, an AGB (aerosol generator and booster) unit 124, as well as an MQL discharge unit 128.

[0038] The first input unit 104 also termed as the air unit 104 is responsible for supplying compressed air to the MQL unit 102. This compressed air defines the first input of the system 100. The MQL control unit 103 includes a second input unit 106 that includes input come display panel 106a, and a manual control panel 106b. The input come display panel 106a allows an operator to provide input parameters i.e. the second input to the system 100 such as dosing unit time (off time and on time), desired MQL aerosol pressure set point. It also displays the actual aerosol pressure in the panel 106a. The manual control panel 106b includes a plurality of switches that allow to provide inputs to the system 100 to operate system 100 in a first auto mode or a second manual mode.

[0039] Referring to FIG. 2, the MQL unit 102 includes an air unit 104, a pneumatic control unit 112, and a reservoir 116. Additionally, the system 100 includes a dosing unit 120, an AGB (aerosol generator and booster) unit 124, as well as an MQL discharge unit 128, and output unit 132. The aerosol is discharged through the output unit 132 and supplied through suitable piping and / or nozzle to the cutting tool location. The discharge unit 128 of the MQL unit 102 includes two sensors such as a pressure transducer sensor 260 and a diaphragm type pressure switch 268 also referred as a third switch 268.

[0040] The system 100 operates by receiving first input in the form of the compressed air from air unit 104, a plurality of user-defined parameters from the second input unit 106, and thirdly the oil as in input from the reservoir 116. It is noted that these three inputs are received simultaneously by the system 100 as configured by the system controls. These three inputs are processed by the MQL unit 102 and combined to produce a finely controlled mixture of vegetable -based oil and air in the form of aerosol. This mixture is delivered under pressure in the form of an aerosol i.e. a very fine mist composed of submicron- sized particles of oil and air through an output unit 132, which is directly connected to the cutting tool of any machine tool such as a lathe, CNC, VMC, HMC, Milling Machine, Drilling Machine, Gear Hobbing Machine, Broaching Machine, Shaping Machine etc. The submicron- sized aerosol ensures efficient lubrication with minimal fluid consumption, enhancing the performance and longevity of the cutting tool. It is noted that in the first Auto Mode of operation, the system 100, is operable in two sub-modes such as a first continuous cycle sub-mode, and a second interrupted cycle sub-mode.

[0041] Referring to FIG. 3, a front view of the air unit 104 is shown, the air unit 104 includes an input tube 150, an input valve 154, and a water separator 158. The output of the water separator 158 is provided to the Pneumatic Control Unit 112 (Ref. FIG. 1). The air unit 104 receives pressurised air i.e., the first input form an external source such as a compressor through the tube 150. The input air received by the air unit 104 is in the range of 4 bar to 10 bar. The water separator 158 is preferably an auto-drain type water separator that removes moisture from the input air in the air unit 104. Accordingly, moisture free air is generated that is provided to the Pneumatic Control Unit 112. The pneumatic Control Unit 112 receives the near moisture free air from the air unit and regulates the pressure in two stages that is then received by the AGB unit 124 and the dosing unit 120. In this one embodiment, the Pneumatic Control Unit 112 includes two types of pneumatic circuits such as a first pneumatic circuit and a second pneumatic circuit.

[0042] Now referring to FIGS 3 A and 3B, the Pneumatic Control Unit 112 includes two types of pneumatic circuits such as a first pneumatic circuit CKT1 and a second pneumatic circuit CKT2. The first circuit CKT1 of the Pneumatic Control Unit 112 is preferably associated with the dosing unit 120. The second circuit CKT2 of the Pneumatic Control Unit 112 is preferably associated with the AGB Unit 124.The first pneumatic circuit receives the dried air from the air unit 104 that is regulated to generate pressurised air having pressure in the range of (4 to 8 bars) that is provided to the dosing unit 120 (Ref. FIG 1). The second pneumatic circuit CKT2 receives the dried air from the first circuit CKT1 that is further regulated to generate pressurised air having pressure in the range of (2 to 5 bar) that is provided to the AGB Unit 124 (Ref. FIG. 1).

[0043] The first pneumatic circuit includes a filter 214, a first regulator 216, a first display DSP1, a first switch 220, and a first valve 224. The filter 212 processes the incoming air from the first input 104, ensuring that only clean and regulated air passes through. The first regulator 216 manages the pressure of the filtered air, which is then delivered to both the dosing unit 120 and the pneumatic control unit 112 via the first valve 224. The first switch 220 acts as a sensor, monitoring the pressure and generating alarms based on user-defined settings through the second input 106. The first switch 220 is also equipped to detect the inlet pressure of the compressed air. For instance, if the pressure drops below a threshold level (e.g., 5 bar), the switch signals the Programmable Logic Controller (PLC) to initiate a system shutdown to prevent operational issues.

[0044] The second pneumatic circuit of the pneumatic control unit 112 features a second valve 228, a second switch (Not seen), a second display and a second regulator 236. The second switch is linked to the second regulator 236, which governs the air supply to the AGB unit 124. The second valve 228 regulates the air flow to the aerosol generator unit 124, ensuring that the system 100 operates under precise and stable conditions.

[0045] As shown in FIG. 4 above, AGB unit 124 includes a motor 400 that is connected to a booster generator 404 via a tensioner 408 through a belt 412 which drives a fusible clutch pulley 413 of the booster generator 404. The fusible clutch pulley 413 provides additional protection to the booster generator 404. A mixture 416 is positioned on the top inlet of the booster generator 404 which receives regulated air from the second pneumatic circuit CKT 2 (Ref. FIG. 3 A. 3B) and dose of oil from the dosing unit 120 (Ref. FIG. 1).

[0046] The AGB unit 124 receives the regulated air from the pneumatic control unit 112 and oil in the form of dose of oil from the dosing unit 120. The AGB unit 124 makes a mixture of air and oil. Further, the AGB unit 124 converts mixture of air and oil in to pressurised aerosol. The dosing unit 120 receives pressurised air from the pneumatic unit 112, and oil from the reservoir 116 that is processed and discharged in the form of a plurality of dose of oil to the AGB unit 124. The quantity of the oil in a dose is set by set lever, and the frequency of dose is configurable by the PLC that is part of the MQL control unit 103.

[0047] Now Referring to FIG. 5 the dosing unit 120 is described. The dosing unit 120 includes an air cylinder 500 supplied flow control-quick exhaust unit 504 which operates a high pressure pump 508 connected by suitable tube 512 to the dosing injector 516 which supplies the accurate dose of oil in the dosing unit block 520. The dosing unit 120 is further protected against failure by a pressure switch / sensor 524.

[0048] The dosing unit 120 discharges a dose of oil in the range of 0.04 ml to 0.08 ml per dose. This dose is received in the AGB unit 124. A dose is a dose of oil that is generated per stroke and that has a predefined quantity of pressurised oil in the above mentioned range. The input to the dosing unit 120 is the oil received from the reservoir 116 by the gravitational force, and output of the dosing unit is the doses that includes pressurised oil of a predefined quantity. The dosing unit 120 includes an inlet tube, an air cylinder, a high pressure pump, an injector, a block and dose discharge tube. The inlet tube and the discharge tube each includes a nonreturn valve.

[0049] The dosing unit 120 has two inputs such as oil through the inlet tube from reservoir 116, and pressurised air received from the pneumatic control unit 112 for operating the cylinder that operates the pump. The block 520 is an approximately rectangular block of material such as aluminium, steel etc. The block 520 includes cavities to mount the air cylinder from the bottom of the block, a high pressure pump from one side of top of the block, and the injector besides the pump on the top portion of the block. The block 520 also includes a sensor (third sensor) defined by a switch. The block 520 includes a cavity through which the dose is discharged by the injector. The third sensor 524 detects the discharge of the does.

[0050] Referring to FIG. 6 above the MQL discharge unit 128 receives aerosol from the AGB unit 124 via tube 600. The MQL discharge unit 128 has a sensor 260, a gauge 264, and a third switch 268. In this embodiment, the sensor 260 is a pressure transducer that detects the pressure from the output unit 132 via the third switch 268 and provides feedback to the booster 256 of AGB Unit 124 via pressure sensor 260 to regulate the pressure via variable frequency drive. The third switch 268 of MQL discharge unit 128 acts as a pressure sensor and also acts as a device to protect the system 100 from over pressure should the sensor 260 fail.

[0051] The sensor 260 is, for example, a piezoelectric crystal transducer or a similar pres sure- sensing device. The MQL discharge unit 128 maintains a consistent pressure based on the predefined quantity of lubricant being delivered through the third switch 268 of MQL discharge unit to the output unit 132 which is connected to the cutting tool through spindle or external open cast to deliver the MQL in the cutting zone. The pressure gauge 264, for example, an analogue gauge, displays the output pressure of the MQL system for monitoring purposes. Further, the sensor 260 provides the MQL pressure to the PLC that is preferably displayed on the display or monitor of the Input Unit 108.

[0052] In another embodiment, the MQL discharge unit 128 is equipped with another pressure sensor, which is a diaphragm-type differential pressure sensor designed to protect the system from overpressure in the MQL discharge. For instance, if the connection between the MQL discharge unit 128 and the respective machine tool becomes blocked, this pressure sensor will signal the PLC to shut down the system 100, thereby preventing any potential damage or malfunction.

[0053] Referring now to FIGS. 7 and 8, the detailed schematic of the system 100 is described in greater depth. The MQL control unit 103 has the input come display panel 106a, and the manual control panel 106b. Through the input come display panel 103a, the user can select and set parameters related to the cutting tools, including air pressure, the amount of Minimum Quantity Lubrication (MQL), the number of strokes, and the frequency of strokes.

[0054] In the preferred embodiment, the air unit 104 receives the compressed air that is dried by removing the moisture through the water separator. The Pneumatic Control Unit 112 includes two types of pneumatic circuits such as a first pneumatic circuit CKT1 and a second pneumatic circuit CKT2. The first pneumatic circuit CKT1 receives the dried air from the air unit 104 that is regulated to generate pressurised air having pressure in the range of 4 to 8 bars that is provided to the dosing unit 120. The second pneumatic circuit CKT2 receives the dried air from the first circuit that is further regulated to generate pressurised air having pressure in the range of (2 to 5 bar) that is provided to the AGB Unit 124.

[0055] The first pneumatic circuit CKT1 includes a filter 212, a first regulator 216, a first display DSP1, a first switch 220, and a first valve 224. The filter 212 processes the incoming air from the first input 104, ensuring that only clean and regulated air passes through. The first regulator 216 manages the pressure of the filtered air, which is then delivered to both the dosing unit 120 and the pneumatic control unit 112 via the first valve 224. The first switch 220 acts as a sensor, monitoring the pressure and generating alarms. It is noted that the user-defined inputs are provided through the second input unit 106. The first switch 220 is also equipped to detect the inlet pressure of the compressed air. For instance, if the pressure drops below a threshold level (e.g., 5 bar), the switch signals the Programmable Logic Controller (PLC) to initiate a system shutdown to prevent operational issues.

[0056] The second pneumatic circuit CKT2 of the pneumatic control unit 112 features a second valve 228, a second switch (Not seen), a second display and a second regulator 236. The second switch is linked to the second regulator 236, which governs the air supply to the AGB unit 124. The second valve 228 regulates the air flow to the AGB unit i.e. aerosol generator unit 124, ensuring that the system 100 operates under precise and stable conditions.

[0057] The first valve 224 plays a critical role in delivering high-pressure air to the dosing unit 120. The dosing unit 120 comprises a cylinder 500, a pump508, and an injector 516. The second valve 228 controls the flow of air to the AGB Unit 124. The pneumatic control unit 112 manages the strokes and timing of the air cylinder 500 of the dosing unit 120, ensuring that the system 100 operates in sync with the selected parameters.

[0058] The air cylinder 500 of the dosing unit, in turn, operates the pump 508, which is rated at 70 bar, and the pump powers the injector 248. The injector 516 is responsible for delivering precise doses of lubricant to the aerosol generator and booster unit 124 at the correct intervals. The aerosol generator and booster unit 124 includes of a mixer 416 and a booster 404. The AGB unit 124 through the mixer 416 receives the dose of oil from the dosing unit 120, and regulated air from the second pneumatic circuit CKT2 of the Pneumatic Control Unit 112. The mixer 416 combines the lubricant from the dosing unit 120 with regulated air from the second valve 228 to generate aerosol mixture of air and oil.

[0059] The booster 404 receives the mixture of air and oil. The booster 404 then generates aerosol from this mixture by an adiabatic process. The booster 404, which may be a vane-type booster, piston-type booster, or piston-type compressor, is driven by an electric motor and further enhances the pressure of the aerosol. The controlled aerosol is then transferred from the aerosol generator unit 124 to the MQL discharge unit 128.

[0060] As shown in FIG. 8 and 9A, now a process flow diagram of the system 100 of the present invention is described as follows.

[0061] 1. Receiving Pressurized Air: Pressurized air is received from an external source as a first input into the air unit 104 of the system 100 as indicated by arrow ‘ 1’ .

[0062] 2. Receiving User Inputs: User inputs are provided through the MQL Control Unit 103 via an input device, enabling the control of various operational parameters as indicated by arrow 2.

[0063] 3. Receiving Oil: Oil is drawn from the reservoir and supplied to the system for further processing as indicated by arrow ‘3’. Oil Dosing: The oil is received by the dosing unit 120, which is configured to create a dose of oil. Accordingly, the oil is supplied by the pump 508 to the injector 516 with the pipe 512 as indicated by arrow ‘4’. Air Input: Pressurized air is directed to the Air Unit 104 as indicated by arrow ‘5’. Moisture Removal: The Air Unit 104 removes moisture from the incoming pressurized air to ensure dry air is used for subsequent steps as shown by arrow ‘6’. Dry Air Supply: The dry air is supplied from the Air Unit 104 to the Pneumatic Control Unit 112 as shown by arrow ‘7’. Pneumatic Regulation: The Pneumatic Control Unit 112 regulates the dry air into two pneumatic circuits for different stages of the process as indicated by arrow ‘8’. First Pneumatic Circuit: The first pneumatic circuit of the pneumatic control unit 112 regulates the air and supplies it to the dosing unit 120 as indicated by arrow ‘9’ . The dosing unit generates a dose of oil and sends it to the mixer 416 for combining the oil in the dose with air as shown by arrow ‘ 10’ . Second Pneumatic Circuit: The second pneumatic circuit CKT2 receives regulated air from the first pneumatic circuit CKT1, and further refines it and provides it to the mixer 416 as indicated by arrow ‘ 11’. 13. Oil Dose to AGB Unit: The AGB Unit 124 receives the oil in the form of a precisely metered dose from dosing unit 120.

[0064] 14. AGB Unit Operation: The AGB Unit 124 receives both the regulated air from the second pneumatic circuit CK2 (Ref. arrow 11) and the oil dose from the dosing unit 120 via mixer 416 (Ref. arrow 10).

[0065] 15. Aerosol Generation: The booster unit processes the mixture and sends it to the booster as shown by arrow ‘ 12’.

[0066] 16. Aerosol Delivery: The AGB Unit 124 creates and delivers the aerosol at the desired pressure to the discharge unit 128 in a direction as shown by arrow ‘ 13’.

[0067] 17. Aerosol Supply: The discharge unit 128 supplies the aerosol to the output unit 132 as shown by arrow ‘ 14’.

[0068] 18. Final Delivery: The output unit 132 directs the aerosol through suitable tubing to either the cutting tool via the spindle or externally via a nozzle, depending on the operational requirements as indicated by arrow ‘ 15’.

[0069] The process described efficiently manages the intake and regulation of pressurized air and oil, which are processed through multiple units, including the Air Unit, Pneumatic Control Unit, and Dosing Unit. The air and oil are precisely regulated and mixed in the AGB Unit to form an aerosol, which is then delivered at the required pressure to the discharge unit and ultimately supplied to the cutting tool. This system 100 by using the preferred process of the present invention ensures accurate dosing and optimal delivery of the air-oil mixture for enhanced operational performance in industrial applications. Referring to FIGS. 9A, 9B and 9C, the PLC is configured to operate the device 100 of the present invention in the first auto mode. In a first step 10, the first and the second input is received. The first input pressurised air from an external source is revived by manually opening a mechanical valve, and second input is from the operator using the input device. In a second step 12, the PLC receives input signal from the first regulator 216. In the next step 14, the PLC checks if that is within the range of the minimum to maximum pressure (less than 4 bar and more than 10 bar). If it is within the range the control goes to next step 16. If the pressure signal is not within the limits then the operation is aborted by the PLC.

[0070] In the next step 16, the PLC activates the first pneumatic solenoid circuit CKT1 that activates the dosing unit 120. In the next step 18, the PLC receives signals from the second pneumatic solenoid circuit CKT2. The pulse received from the CKT2 is checked by PLC in the next step 20. If the PLC fails to receive the signal or the pulse it will abort the operation immediately. If the signal is received, the control goes to next step 22. In the next step 22, the PLC opens the second solenoid valve 228 that provides air to the aerosol generator and booster unit i.e. AGB Unit 124.

[0071] In the next step 24, the aerosol generator and booster unit 124 is activated. In this step the motor is started and the belt driven booster pump is also activated simultaneously. In the next step 26, PLC takes signal from the sensor 260. The signal is checked. If the PLC fails to receive signal the operation is aborted. If the signal is received, then then PLC check the strength of the signal and does conditioning of signals in the next step 28. The conditioning of signal includes modulating the speed of the motor to receive speed required to generate required pressure. This continues and the control goes to next step 30.

[0072] In the step 30, the PLC receives the input from the third switch 268 i.e. the pressure sensor. If the signal from the third switch 268 is received then the operation continues, otherwise the PLC aborts the operation. The operation is continued by the PLC till the such time the operator input or the operator stops the system 100.

[0073] Now referring to FIGS. 1 to 9, in the operation the dosing unit 120 receives oil from the reservoir 116 through the input tube of the dosing unit 120, and also receives second input in the form of pressurised air from the Pneumatic Control Unit 112 that is in the range of (4 bar to 8 bar). The pressurised air from the Pneumatic Control Unit 112 is received through a flow control valve and a quick exhaust valve. As a result, a piston in the cylinder reciprocates translating the motion to the high pressure pump that is a positive displacement pump. The pump receives oil from the reservoir by gravitational force all the time. The pump that is receiving oil from the reservoir generates a flow of high pressure oil that is provided to the injector. The process of generating high pressure oil and providing that to the injector is continuously ongoing process during the operation of the dosing unit. The injector creates a dose of oil from the pressurised oil at a break inn pressure of approximately 50 bar to 70 bar. The dose is delivered in the dosing cavity of the dosing unit 120. The dose is then delivered from the output tube of dosing unit 120 via the non-retum valve.

[0074] It is noted that the dosing unit 120 is connected to the AGB unit 124. The MQL discharge unit 128 receives its input from the AGB Unit 124. The input unit 106 serves as an interface between the user and the machine tool, allowing for control and resetting of the system 100. It also facilitates the delivery of compressed air to the air unit 104.

[0075] The air unit 104 receives compressed air from the input unit 106 and ensures the air is filtered and regulated before being supplied to the pneumatic control unit 112. The output unit 132 includes a throttle valve equipped with a predefined orifice, which is responsible for generating an apparent ambient pressure within the discharge block. This pressure is then detected by a sensor 260, typically a pressure transducer, which monitors and ensures the stable operation of the aerosol generator and booster unit 124. The sensor 260 is preferably an analogue type sensor that provides the signals to the PLC.

[0076] The sensor 260 transmits its readings as feedback to the control system, which is typically managed by a Programmable Logic Controller (PLC) or a similar regulating device. This real-time feedback loop enables the control system to accurately monitor and regulate the pressure, ensuring consistent and efficient operation of the MQL system throughout the machining process.

[0077] If the sensed pressure deviates from the desired level by modulating the booster motor speed in closed loop via VFD and sensor 260 which is required for the stable operation of the aerosol generator and booster unit 124. For example, it may alter the operation of the aerosol generator or booster unit to maintain the correct pressure levels. In this way, the orifice generates the needed back pressure, while the sensor 260 continuously provides real-time feedback to the PLC. This feedback enables the PLC to make continuous, dynamic adjustments, ensuring the stable operation of both the aerosol generator and booster unit. This process forms a closed-loop control system, effectively maintaining the desired operating conditions throughout the machining operation.

[0078] The output unit 132 is replaceable and removable, offering flexibility to adapt to specific operational requirements, such as the desired Cubic Feet per Minute (CFM) of aerosol output or the number of nozzles in use. Different sizes and configurations of the output unit 132 can be selected and easily installed, allowing the system to adjust to these varying parameters. This modular design ensures optimal performance and provides the flexibility needed to efficiently meet different application needs by simply replacing the output unit when necessary.

[0079] Accordingly, the pneumatic control unit 112 plays a key role in generating and controlling the variable strokes necessary for the system's operation. It also manages the timing of the air cylinder strokes within the dosing unit 120, based on user-selected settings and inputs provided through the input unit 106. The reservoir 116, which stores the lubricant, typically an eco-friendly blend of vegetable -based ester lubricant, is strategically positioned to supply lubricant to the dosing unit 120 either by gravitational force, assisted by a non-retum valve (NRV), or through a small feed pump. The reservoir 116 is also equipped with a transparent cover, allowing for easy monitoring of the lubricant level during refilling.

[0080] The dosing unit 120 accurately meters the required amount of lubricant and sends it to the aerosol generator and booster unit 124. This transfer occurs via a non-retum valve (NRV), ensuring a precise and controlled quantity of lubricant reaches the aerosol generator unit 124. The aerosol generator unit 124, which includes a mixer and a booster, is responsible for both generating the aerosol and boosting the air pressure. The aerosol generator unit 124 is powered by an electric motor, typically ranging between 0.75 to 3 kilowatts, depending on the demand for aerosol generation.

[0081] The aerosol generator unit 124 is controlled by an electric motor (not shown in FIG. 1) and operates based on pressure signals received from the discharge unit 128. These signals are processed via a variable frequency drive (also not shown in FIG. 1) that modulates the motor's speed to maintain the desired pressure. The aerosol generator unit 124 then delivers the Minimum Quantity Lubricant (MQL) in the form of a finely controlled aerosol to the output unit 132 through the MQL discharge unit 128.

[0082] The MQL discharge unit 128 not only ensures the delivery of a controlled quantity of aerosol lubricant but also provides feedback to the variable frequency drive via sensor 260 which in turn regulates the electric motor driving the aerosol generator and booster unit 124. This feedback loop enables the system 100 to precisely control the dose of oil and compressed air delivered to the aerosol generator and booster unit 124. The variable pressure required for different cutting tools is managed by the pneumatic control unit 112, the aerosol generator unit 124, and the electric motor, ensuring that the system adapts efficiently to varying operational demands.

[0083] In actual operation, an operator has freedom to select the mode of operating system 100. In the first continuous cycle mode, the aerosol discharge by the system 100 is continuous. In the second interrupted mode the pressure required is in the large quantity for chip evacuation however, so much of aerosol is not required. The system 100, in the first auto mode is operable in two sub- modes such as a first continuous cycle sub-mode or a second interrupted cycle sub-mode. Mode or submode selection is done by providing input to the first unput unit 106a of the MQL control unit 103. The type of the mode is selected by the operator operating the system 100.

[0084] Now the operational cycle of the system 100 is explained as follows. The system 100 receives compressed air and user-defined parameters via the input unit 106, along with oil from the reservoir 116, to deliver a precise quantity of Minimum Quantity Lubrication (MQL) oil and air pressure to the output unit 132, which is connected to either the cutting tool or an open nozzle. Now the type of the mode is also provided from the first continuous mode or the second interrupted mode.

[0085] The first input is provided by the first unit 104 that supplies compressed air, while the second input unit 106 including 106a and 106b allows to provide the second input that is entered by the users. It is noted that the second input unit 106 advantageously serves as an interface and control where the user selects and configures parameters such as air pressure, the quantity of MQL, number of strokes, and stroke frequency for the cutting tools.

[0086] The MQL control unit 103 interfaces with the MQL Unit 102 and machine tool CNC system. It acts as the control panel, equipped with various components such as a control unit, human-machine interface (HMI) unit, variable frequency drive (VFD), control contacts, electrical protection devices, switches, power supplies, and other electrical equipment. The second unit 103 also generates alarms for conditions like the absence of air generation by the air unit 104, low or high air pressure from the pneumatic control unit 112, or lack of air generation by the aerosol generator and booster unit 124 within a predefined time interval. The HMI may be touch type or key type input interface.

[0087] The air unit 104 receives compressed air, typically at a pressure of 6 bars, from the first input 104. The air passes through the filter 212, which removes impurities, and the filter can be a paper, ceramic, or vitreous type with a water separator. The filtered air is then sent to the first regulator 216, which maintains the pressure between 3 to 10 bars. The regulator 216 can be of the common cavity equalizing type, from manufacturers such as FESTO, SMC, or Janamatics, and features either an analog or digital switch gauge. The regulated air is then distributed to both the dosing unit 120 and via the pneumatic control unit 112 through the first valve 224, which is an electric solenoid valve.

[0088] The first switch 220, which functions as a pressure switch, is connected to the first regulator 216 and generates fault signals if the air pressure is too low or too high. Based on these signals, the system 100 generates alarms as per user settings done by the user via the MQL Control Unit 103. Similarly, the sensor 524 installed on the dosing unit 120 monitors the operation of the dosing unit 120. The second switch (Not Seen) is removably positionable in the second pneumatic circuit CKT2 as per the requirement.

[0089] The pneumatic control unit 112 is responsible for regulating the airflow to both the aerosol generator and booster unit 124 and the dosing unit 120. It also controls the strokes per minute and the timing of the air cylinder 500, as per the user inputs from the MQL control unit 103. The air cylinder 500, which is connected to a high-pressure pump and injector assembly within the dosing unit 120, operates based on the variable pressure requirements set by the user. In this one ambient, the injector assembly is brake inn pressure type injector assembly which operates on pressure pulse and doesn’t need any external actuation.

[0090] The dosing unit 120 has the cylinder 500 that operates high pressure pump 508 that is preferably a plunger pump or piston pump. The pump 508 is connected to the injector 516 that delivers predefined dose. The dose is adjustable by changing the deliver quantity of the pump 508 by operating a lever located in the pump 508. The dose is also adjustable by changing the setting on the injector i.e., by controlling load on a load spring of the injector nozzle. The dosing unit 120, powered by the first valve 224, receives lubricant from the reservoir 116. It supplies the lubricant in precise doses (ranging from 0.04 ml to 0.4 ml per stroke) to the booster and aerosol generator unit 124 at regular intervals, as controlled by the MQL control unit 103. The booster and aerosol generator unit 124 works on principle of change in adiabatic pressure to generate aerosol.

[0091] The dosing unit 120 operates on the principle of compression and pressure reduction and includes a pulse-type pressure sensor 524 that detects whether a lubricant dose has been successfully generated. The sensor 524 is positioned within the collector cavity, and when the injector delivers a dose of oil at approximately in the range of (30 to 70) bar, the sensor transmits a confirmation signal to the Programmable Logic Controller (PLC). If a dose is not generated, the sensor alerts the PLC, triggering an operational halt and displaying a failure notification for the dosing unit 120 on the display of the control unit 106.

[0092] The air cylinder 500 powers the pump 508, which is rated at 110 bar, and the pump drives the injector 516 via a connecting tube 512 to deliver the high- pressure lubricant dose to the aerosol generator and booster unit 124. The injector 516 operates and delivers a precise quantity of lubricant at regular intervals to the aerosol generator unit 124 through a non-return valve as configured by the user.

[0093] The air from the air unit 104 and the lubricant from the dosing unit 120 are combined in the aerosol generator and booster unit 124, which is responsible for atomizing and boosting the air pressure. The booster 404, operating in a closed- loop system with the sensor 260 and a variable frequency drive (VFD), adjusts the pressure to maintain the desired MQL output. The sensor 260, an analogue pressure transducer 260, generates an output voltage / current ranging from (4 to 20 millivolts / milliamps), corresponding to an actual pressure range of 4 to 16 bars. This pressure signal is transmitted to the PLC, which adjusts the VFD to control the speed of the aerosol generator and maintain the pre-set MQL pressure. In another embodiment, the aerosol generator is also operable in open-ended circuit by manual control of VFD (Variable Frequency Drive) via a potentiometer to provide desired MQL aerosol pressure at a fixed value, for example, 5 bars or 10 bars or like that.

[0094] The aerosol generator unit 124 then delivers the controlled air and lubricant mixture to the MQL discharge unit 128. The sensor 260 continuously monitors the pressure, and the MQL discharge unit 128 provides a constant pressure as per the predefined quantity of aerosol to the output unit 132. The systemlOO operates in a closed-loop configuration, with the booster 256 adjusting based on the feedback provided by the sensor 260. It is noted that the system 100 of the present invention is operable in 220 Volt single phase or 440 Volt three phase as required by the user.

[0095] The system 100 provides several advantages, including enhanced cutting tool performance, an increased number of cuts per tool, and extended tool life. It improves the efficiency of cutting operations, reduces friction by 80 to 90%, and eliminates the need for traditional cooling methods. The system 100 is also cost- effective, increasing cutting speed, productivity, and overall operational efficiency by minimizing downtime and optimizing tool usage.

[0096] The system 100 of the present invention doesn’t require any external booster as a first source of pneumatic supply thereby saving cost and reducing carbon footprint. Additionally, the system 100 is environmentally friendly, as it utilizes a biodegradable, non-hazardous, and inexpensive vegetable-based lubricant. By eliminating the use of water, and mineral / synthetic oil based traditional coolants, the system 100 creates a safer and more sustainable industrial environment. This reduction in friction and heat significantly lowers the likelihood of tool failure, reduces machine downtime, and ultimately improves overall productivity, making the system 100 a more economical and eco-friendlier alternative to conventional lubrication methods.

[0097] The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others, skilled in the art to best utilize the present invention and various embodiment's with various modifications as are suited to the particular use contemplated.

[0098] It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.

Claims

Claims1. A localized Minimum Quantity Lubrication (MQL) system (100) delivering a controlled and precise amount of lubrication in the form of aerosol directly to a cutting tool, the system comprising: a. an MQL unit (102) removably positionable on a platform, the MQL unit (102) including: i. an air unit (104) supplying compressed air; ii. a pneumatic control unit (112) regulating the compressed air into at least two pneumatic circuits; iii. a reservoir (116) supplying oil; iv. a dosing unit (120) receiving compressed air and oil, and generating metered doses of pressurized oil; v. an aerosol generator and booster (AGB) (124) unit receiving the metered doses of oil and regulated air, mixing the oil and air, and generating a pressurized aerosol; vi. an MQL discharge unit (128) receiving the pressurized aerosol from the AGB unit and delivering it to an output unit; b. an MQL control unit (102) having: i. an input-display panel (106a) receiving user-defined parameters and displaying operational data; andii. a manual control panel (106b) enabling operation in an automatic or manual mode; and c. an output unit (132) delivering the pressurized aerosol to a cutting tool.

2. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the air unit (104) including an input tube (150) receiving compressed air from an external source, a water separator (158) removing moisture from the compressed air, an input valve (154) regulating the flow of compressed air; and a pressure regulator maintaining the compressed air within a range of 4 bar to 10 bar.

3. The localized Minimum Quantity Lubrication (MQL) system of claim 1, wherein the pneumatic control unit (112) including a first pneumatic circuit CTK1 supplying pressurized air to the dosing unit (120), and a second pneumatic circuit CTK2 supplying regulated air to the AGB unit (124).

4. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 3, wherein the pneumatic control unit (112) including a first regulator (216) and valve for the first pneumatic circuit CTK1, a second regulator (236) and valve for the second pneumatic circuit CTK2, and pressure sensors (260) and switches monitoring and controlling air pressure within the circuits.

5. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the dosing unit (120) including an air cylinder (500) operating ahigh-pressure pump (508), a dosing injector (516) delivering precise doses of pressurized oil, a block (520) housing the air cylinder (500), pump (508), and injector (516), an inlet tube connected to the reservoir (116) and including a non-retum valve, and a discharge tube including a non-return valve for delivering pressurized oil to the AGB unit (124).

6. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the AGB unit (124) including a mixer (416) combining oil doses with regulated air to form a mixture, a booster (404) converting the mixture into a pressurized aerosol using an adiabatic process, and a motor-driven mechanism powering the booster (404).

7. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the MQL discharge unit (128) including a pressure sensor (260) providing real-time pressure feedback to a programmable logic controller (PLC), a pressure gauge (264) monitoring output pressure, and a third switch (268) preventing overpressure conditions.

8. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the MQL control unit (103) further including a programmable logic controller (PLC) managing operational parameters; a human-machine interface (HMI) enabling mode selection and parameter adjustments; and alarm systems indicating abnormal operating conditions.

9. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the output unit (132) is replaceable and configurable to deliverthe aerosol through a spindle to the cutting tool or an external nozzle to the cutting zone.

10. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the system (100) operable in modes a first automatic modes and a second manual mode; the automatic mode including a continuous cycle mode delivering constant aerosol and an interrupted cycle mode delivering periodic aerosol with increased pressure for chip evacuation.

11. The localized Minimum Quantity Lubrication (MQL) system (100) of claim 1, wherein the lubricant including a biodegradable, non-hazardous vegetable-based oil.

12. A method of operating the localized MQL system (100) of claim 1, the method comprising: a. supplying compressed air to the air unit (104); b. regulating the compressed air into at least two pneumatic circuits via the pneumatic control unit (112); c. delivering oil from the reservoir (116) to the dosing unit (120); d. generating metered doses of pressurized oil in the dosing unit (120); e. mixing the pressurized oil with regulated air in the AGB unit (124) to form an aerosol; f. boosting the pressure of the aerosol in the AGB unit (124); andg. delivering the pressurised aerosol through the output unit (132) to a cutting tool.

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