Alternating magnetic field ultrasonic-assisted trace lubricant traction infiltration turning system and method

Abstract

The invention discloses an alternating magnetic field ultrasonic-assisted trace lubricant traction infiltration turning system and method, and relates to the technical field of ultra-precision machining, and the system comprises a composite energy field turning device and a trace lubrication system; the composite energy field turning device comprises an ultrasonic vibration device, an alternating magnetic field generation device and a tool. A nozzle in the minimum quantity lubrication system corresponds to one side of the tool. The ultrasonic vibration device comprises a first ultrasonic vibrator and a second ultrasonic vibrator which are perpendicular to each other, the cutter is installed at the tail end of the first ultrasonic vibrator and the tail end of the second ultrasonic vibrator, and the first ultrasonic vibrator and the second ultrasonic vibrator jointly provide two-dimensional ultrasonic vibration. The alternating magnetic field generating device comprises a first electromagnet and a second electromagnet, the first electromagnet is obliquely installed above the tool, and the second electromagnet is horizontally installed below the tool. According to the invention, an alternating magnetic field and two-dimensional ultrasonic vibration are fused to play roles in two aspects of lubricant transport reinforcement and interface lubrication improvement, and the lubrication effect is further improved through a coupling effect.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision machining technology, and in particular to an alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system and method. Background Technology

[0002] In turning, the cutting zone exhibits high temperature, high pressure, and strong friction under high-speed conditions. Heat is concentrated significantly at the tool tip, making it prone to failure modes such as adhesive wear, crater wear, and micro-chipping, leading to reduced tool life and increased fluctuations in machining quality. To improve friction and heat dissipation in the cutting zone, existing technologies often employ cutting fluid injection, jet cooling, or quantity moderated lubrication (MQL) to supply lubricating media to the tool-chip interface. However, under high-speed turning conditions, the high-speed relative sliding between the tool rake face and the workpiece / chip induces a stable air boundary layer or "air barrier," which forms an airflow shield and pressure gradient at the cutting zone inlet. This makes it difficult for atomized lubricant to effectively enter the tool tip region and the tool-chip interface. The lubricating medium is easily carried away by the airflow, diffuses and deposits on the outside, or only acts on the outer surface of the chip, thus limiting the actual friction-reducing and cooling effect of MQL.

[0003] Ultrasonic vibration-assisted turning can reduce average cutting force, improve chip breaking and friction conditions through periodic separation and micro-cutting action, and facilitate the renewal and diffusion of lubricating media within the interface. However, relying solely on ultrasonic vibration-assisted turning may still be affected by the shielding effect of an air barrier layer under high-speed conditions, making it difficult for the lubricant to reach the critical area of ​​the tool tip stably. Existing technologies also include cutting systems using high-pressure micro-volume liquid lubricants. These systems deliver the lubricant to the internal channels of the tool through an input pipe via a supply device. A main cooling chamber is located within the tool body, and a secondary cooling chamber is located in the contact area between the tool holder and the tool body. The heated lubricant can be returned to the oil tank through circulation and output pipes. However, this approach mainly relies on pressure delivery, and its stability is affected by operating conditions.

[0004] Since ultrasonic vibration-assisted methods, high-pressure or micro-lubrication methods all have certain limitations, existing technologies have also considered introducing alternating magnetic field technology. However, ultrasonic-assisted methods are mainly used to improve the contact state between the tool and the chip, high-pressure or micro-lubrication methods are mainly used to improve the lubricating medium delivery capacity, while alternating magnetic field technology relies on magnetic response medium to achieve directional traction. The above technologies have different mechanisms of action, and when integrated in the limited space of the tool, they face problems such as magnetic circuit arrangement, vibration transmission, and control matching. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide, in particular, an alternating magnetic field ultrasonic-assisted micro-lubricant traction immersion turning system and method. This system integrates alternating magnetic field with two-dimensional ultrasonic vibration, which works from two aspects: enhanced lubricant transport and improved interfacial lubrication. Furthermore, the lubrication effect is enhanced through coupling effect.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, embodiments of the present invention provide an alternating magnetic field ultrasonic-assisted micro-lubricant traction-wetting turning system and method, including a composite energy field turning device and a micro-lubrication system, wherein the micro-lubrication system stores magnetic nano-lubricant; The composite energy field turning device includes an ultrasonic vibration device, an alternating magnetic field generator and a cutting tool, with the nozzle in the micro-lubrication system corresponding to one side of the cutting tool. The ultrasonic vibration device includes a first ultrasonic transducer and a second ultrasonic transducer that are perpendicular to each other. The cutter is installed at the ends of the first ultrasonic transducer and the second ultrasonic transducer. The first ultrasonic transducer and the second ultrasonic transducer together provide two-dimensional ultrasonic vibration. The alternating magnetic field generating device includes a first electromagnet and a second electromagnet, wherein the first electromagnet is installed obliquely above the cutter and the second electromagnet is installed horizontally below the cutter.

[0007] As a further implementation, both the first ultrasonic transducer and the second ultrasonic transducer are mounted on a support base, wherein the first ultrasonic transducer is arranged along the Z-direction and the second ultrasonic transducer is arranged along the X-direction. A force gauge is installed at the bottom of the support base.

[0008] As a further implementation, the tool is installed perpendicular to the first ultrasonic transducer and coaxially with the second ultrasonic transducer.

[0009] As a further implementation, the first electromagnet is set at an acute angle to the horizontal plane, and an installation gap is reserved between the lower side of the first electromagnet and the top surface of the tool holder.

[0010] As a further implementation, the gap between the second electromagnet and the bottom surface of the tool holder is smaller than the installation interval between the first electromagnet and the top surface of the tool holder.

[0011] As a further implementation, the first electromagnet and the second electromagnet each include a pole core, a coil, and a magnetic shielding sleeve, wherein the coil is wound around the outer periphery of the pole core, and the magnetic shielding sleeve is wrapped around the pole core and the outside of the electromagnet.

[0012] As a further implementation, the pole core of the first electromagnet has a block structure, and the pole core of the second electromagnet has a Z-shaped structure.

[0013] As a further implementation, the composite energy field turning device is installed inside a CNC machine tool, and the CNC machine tool is equipped with a main controller; The ultrasonic vibration device is connected to the main controller via an ultrasonic drive module, and the alternating magnetic field generator is connected to the main controller via a magnetic field drive module.

[0014] Secondly, embodiments of the present invention provide a control method for an alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system, comprising: The workpiece is turned based on preset parameters, and the cutting force waveform signal is output by the force measuring instrument during the machining process; The cutting force waveform is feature extracted and analyzed, and it is determined whether the current parameter combination needs to be optimized. If no optimization is needed, the parameters are directly output. If optimization is needed, the parameters of the alternating magnetic field generator, the ultrasonic vibration device, and the micro-lubrication system are adjusted respectively. After the optimization target is met, the optimized parameters are output.

[0015] As a further implementation, the parameters of the alternating magnetic field generator include alternating magnetic field current, frequency, and amplitude; the parameters of the ultrasonic vibration device include ultrasonic vibration frequency, amplitude, and phase; and the parameters of the micro-lubrication system include lubricant flow rate, air pressure, and pulse frequency.

[0016] The beneficial effects of this invention are as follows: The turning system of this invention includes a composite energy field turning device, which consists of an ultrasonic vibration device, an alternating magnetic field generator, and a cutting tool. The ultrasonic vibration device is a two-dimensional ultrasonic vibration device, and the alternating magnetic field generator includes a first electromagnet and a second electromagnet. The first electromagnet is installed obliquely above the cutting tool, and the second electromagnet is installed horizontally below the cutting tool. The alternating magnetic field enhances the directional migration, local enrichment, and interface penetration of the droplets by applying periodic magnetic force and magnetostriction to the lubricant containing magnetic nanoparticles, thereby weakening the obstruction of the air barrier layer on the lubricant and promoting the transport of the lubricating medium to the tool tip micro-area and the tool-chip contact interface. At the same time, the two-dimensional ultrasonic vibration reduces the cutting force and interface friction by means of high-frequency periodic separation, micro-impact, and vibration pumping effect, reduces the wetting resistance of the lubricant under high-speed shearing conditions, and accelerates its renewal, spreading, and film formation in the contact area. Therefore, the alternating magnetic field and the two-dimensional ultrasonic vibration play a role from the two levels of lubricant transport enhancement and interface lubrication improvement, respectively, and further enhance the lubrication effect through coupling effect. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1This is a schematic diagram of the turning system structure according to one or more embodiments of the present invention; Figure 2 This is a schematic diagram of a machine tool structure according to one or more embodiments of the present invention; Figure 3 This is a schematic diagram of the composite energy field turning device according to one or more embodiments of the present invention; Figure 4(a) is a top view of the composite energy field turning device according to one or more embodiments of the present invention; Figure 4(b) is a cross-sectional view of the composite energy field turning device AA according to one or more embodiments of the present invention; Figure 5 This is a schematic diagram of the micro-lubrication system structure according to one or more embodiments of the present invention; Figure 6(a) is a schematic diagram of the first electromagnet structure according to one or more embodiments of the present invention; Figure 6(b) is a cross-sectional view of the first electromagnet BB according to one or more embodiments of the present invention; Figure 7(a) is a schematic diagram of the second electromagnet structure according to one or more embodiments of the present invention; Figure 7(b) is a CC cross-sectional view of the second electromagnet according to one or more embodiments of the present invention; Figure 8 This is a signal control diagram according to one or more embodiments of the present invention; Figure 9 This is a waveform diagram of the alternating excitation current of two sets of electromagnets according to one or more embodiments of the present invention, wherein the solid line corresponds to the current input of the first electromagnet and the dashed line corresponds to the current input of the second electromagnet. Figures 10(a) and 10(b) are schematic diagrams illustrating the working principle of the present invention according to one or more embodiments; Figure 11 This is a schematic diagram of the directional penetration of magnetic lubricating medium into the cutting interface under the action of an external magnetic field coupling according to one or more embodiments of the present invention; Figure 12 This is a control flowchart of a micro-lubrication turning system according to one or more embodiments of the present invention.

[0019] Among them, I. CNC machine tool, II. Composite energy field turning device, III. Workpiece, IV. Micro-lubrication system; Ⅰ-1, Protective door; Ⅰ-2, Alarm light; Ⅰ-3, Machine tool spindle box; Ⅰ-4, Three-jaw chuck; Ⅰ-5, Tool post; Ⅰ-6, CNC system; Ⅰ-7, Feed mechanism; II-1, First ultrasonic transducer; II-2, First fixed plate; II-3, First support plate; II-4, First irregular plate; II-5, First electromagnet; II-6, Knife handle; II-7, Blade; II-8, Second irregular plate; II-9, Second electromagnet; II-10, Force gauge; II-11, Fixed knife holder; II-12, Second fixed plate; II-13, Second ultrasonic transducer; II-14, Second support plate; IV-1, Oil reservoir; IV-2, Precision lubrication pump; IV-3, Precision pneumatic pump; IV-4, Pneumatic frequency generator; IV-5, Gas pressure regulating filter; IV-6, Gas fine adjustment knob; IV-7, Flow regulating valve; IV-8, Lubricant fine adjustment knob; IV-9, Nozzle. II-1-1, Pre-tightening bolt; II-1-2, Rear mass block; II-1-3, Piezoelectric ceramic block; II-1-4, Front mass block; II-1-5, Fastening bolt; II-5-1, First magnetic shielding sleeve; II-5-2, First coil; II-5-3, First pole core; II-9-1, Second pole core; II-9-2, Second coil; II-9-3, Second magnetic shielding sleeve. Detailed Implementation

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] For ease of description, the words "upper," "lower," "front," and "rear" appearing in this invention only indicate that they are consistent with the upper, lower, front, and rear directions of the accompanying drawings. They do not limit the structure and are merely for the purpose of facilitating the description of this invention and simplifying the description. They do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Example 1: This embodiment provides a system and method for ultrasonic-assisted micro-lubricant traction impregnation turning using an alternating magnetic field, such as... Figure 1 and Figure 2 As shown, it mainly includes a CNC machine tool I, a composite energy field turning device II, and a micro-lubrication system IV. The composite energy field turning device II is installed inside the CNC machine tool I, and the main body of the micro-lubrication system IV is installed at the bottom of the machine tool I. Among them, the composite energy field turning device II includes an ultrasonic vibration device, an alternating magnetic field generator, and a cutting tool. The ultrasonic vibration device is used to generate ultrasound to separate the chips at high frequency and form micro gaps. The alternating magnetic field generator is used to generate and adjust the magnetic field. The alternating magnetic field and the two-dimensional ultrasonic vibration play a role from the two levels of enhancing lubricant transport and improving interface lubrication, respectively, and further enhance the lubrication effect through the coupling effect.

[0023] like Figure 3 As shown, the ultrasonic vibration device includes a first ultrasonic transducer II-1, a second ultrasonic transducer II-13, etc. The axes of the first ultrasonic transducer II-1 and the second ultrasonic transducer II-13 are perpendicular to each other, forming two-dimensional ultrasonic vibration. In this embodiment, the first ultrasonic transducer II-1 is installed along the Z-direction, and the second ultrasonic transducer II-13 is installed along the X-direction, that is, the second ultrasonic transducer II-13 is set in the same direction as the machine tool spindle; through the orthogonally arranged two-dimensional ultrasonic vibration, the vibration energy can act simultaneously in two mutually perpendicular directions, causing the tool and the chip to generate high-frequency periodic separation and re-contact during the cutting process.

[0024] like Figure 3 As shown in Figures 4(a) and 4(b), the first ultrasonic transducer II-1 and the second ultrasonic transducer II-13 are mounted above the force gauge II-10 via a support base. The force gauge II-10 is fixed on the fixed tool holder II-11. In this embodiment, the fixed tool holder II-11 has a Z-shaped plate structure, with the force gauge II-10 mounted on one end and an outward-extending double-arm structure on the other end. During assembly, the double-arm structure is used to fit into the pre-set slot of the lathe tool holder I-5, thereby realizing the rapid installation and stable clamping of the composite energy field turning device II on the lathe tool holder I-5.

[0025] The support structure can be configured according to actual conditions. In this embodiment, the support includes a first fixing plate II-2, a second fixing plate II-12, a first support plate II-3, and a second support plate II-14. The first support plate II-3 and the second support plate II-14 are symmetrically arranged on the upper side of the force measuring instrument II-10, and an installation space for the ultrasonic transducer and the alternating magnetic field generating device is formed between them.

[0026] In this embodiment, the first support plate II-3 and the second support plate II-14 are L-shaped structures, and their top ends are connected by the first fixing plate II-2. The first ultrasonic transducer II-1 is fixed to the first fixing plate II-2 along the Z direction. The two first support plates II-3 and the second support plate II-14 are also connected to a second fixing plate II-12 on one side, and the second ultrasonic transducer II-13 is installed through the second fixing plate II-12.

[0027] like Figure 3As shown in Figures 4(a) and 4(b), the ends of the first ultrasonic transducer II-1 and the second ultrasonic transducer II-13 are connected to the same cutting tool, which includes a tool holder II-6 and a blade mounted on the tool holder II-6. The ultrasonic transducer includes a front mass block II-1-4, multiple piezoelectric ceramic blocks II-1-3, and a rear mass block II-1-2 arranged sequentially. The front mass block II-1-4 of the ultrasonic transducer is connected to the tool holder II-6 by fastening bolts II-1-5, and the rear mass block II-1-2 is connected to the corresponding fixing plate by pre-tightening bolts II-1-1, so that the ultrasonic transducer and the cutting tool form a stable connection, ensuring that the ultrasonic vibration energy is effectively coupled to the tool holder II-6 to achieve composite vibration excitation. Gaskets are provided at the contact interfaces between the piezoelectric ceramic block II-1-3 and the front mass block II-1-4 and the rear mass block II-1-2 to avoid direct contact between the piezoelectric ceramic block II-1-3 and the mass block, which could lead to damage, and to reduce stress concentration during the assembly pre-tightening process.

[0028] This embodiment employs ultrasonic vibration to assist in the lubricant wetting and continuous supply at the closed interface between the chip and the cutting tool. By applying two-dimensional ultrasonic vibration to the cutting tool, a high-frequency periodic "contact-separation" state is generated between the tool and the chip. During the separation phase, the interface forms instantaneous gaps and microchannels, thus creating a wetting space for lubricant entry and spread, reducing the resistance to lubricant penetration through the closed interface. Simultaneously, under the pumping / delivery action of a precision lubrication pump, the magnetic nano-lubricant gains directional driving force, enabling it to be rapidly guided and replenished to the vicinity of the cutting tool tip and the cutting tool-chip contact area when the separation window appears, improving lubricant arrival efficiency and coverage.

[0029] Furthermore, the calculation method for two-dimensional ultrasonic vibration is as follows: The driving electrical signals for the two oscillators can be expressed as follows:

[0030]

[0031] in: These are the driving voltage amplitudes; , These are the vibration frequencies in two directions, respectively; , These are the initial phases.

[0032] Correspondingly, the vibration displacement of the blade tip in two directions can be expressed as:

[0033]

[0034] in: and These represent the amplitudes in the horizontal and vertical directions, respectively.

[0035] By adjusting the amplitude, frequency, and phase difference of the two-directional driving signals, the tool tip can form a linear, elliptical, or nearly circular composite vibration trajectory, thereby creating a high-frequency periodic contact-separation state between the tool and the chip, and constructing instantaneous micro-gap and micro-channel within the closed interface.

[0036] In this embodiment, the alternating magnetic field generating device includes a first electromagnet II-5 and a second electromagnet II-9, both of which are installed inside the first support plate II-3. The alternating magnetic field is generated in the target area by the first electromagnet II-5 and the second electromagnet II-9 to apply a magnetic field to the magnetic medium, magnetic lubricant, or fluid containing magnetic particles.

[0037] like Figure 3 As shown in Figure 4(b), the first electromagnet II-5 is positioned above the second electromagnet II-9, and the first electromagnet II-5 is installed at a certain angle. The first electromagnet II-5 is fixed to the inner wall of the first support plate II-3 through the first irregular plate II-4. The first irregular plate II-4 has a horizontal section and an inclined section connected as one piece. The first electromagnet II-5 is fixed to the inclined section, forming an inclined downward installation method.

[0038] Therefore, the first electromagnet II-5 is installed above the handle II-6 at an angle downwards, with a certain installation gap between its lowest point and the top surface of the handle II-6. In this embodiment, the installation gap is 2cm to 5cm, and the specific value can be set according to the actual situation. At the same time, the center plane of the first electromagnet II-5 forms a preset angle with the horizontal center plane of the handle II-6, and this angle is an acute angle; the specific value of the angle can be set according to the actual situation. The second electromagnet II-9 is fixed to the inner wall of the first support plate II-3 through the second irregular plate II-8, and the second electromagnet II-9 is installed below the handle II-6, with a small gap reserved between it and the bottom surface of the handle II-6. This gap is 0 to 3mm, and the specific value can be set according to the actual situation. At the same time, the center plane of the second electromagnet II-9 is parallel to the horizontal center plane of the handle II-6.

[0039] This embodiment employs a first electromagnet II-5 tilted above the tool holder II-6 and a second electromagnet II-9 horizontally positioned below the tool holder II-6. The two work together to form an asymmetrically distributed alternating magnetic field and magnetic field gradient in the cutting area of ​​the tool tip. The asymmetrical structure allows the magnetic field direction of the upper electromagnet to form a preset angle relative to the axis of the tool holder II-6, thereby generating a directional magnetic field component along the cutting zone in the tool tip entry area. This facilitates the attraction of the magnetic nano-lubricant to the critical micro-region of the tool tip. The horizontally positioned second electromagnet II-9 below forms a relatively stable magnetic field support area at the lower part of the tool tip, enhancing the local magnetic field convergence and gradient constraint effect near the tool tip.

[0040] As shown in Figures 6(a) and 6(b), the first electromagnet II-5 includes a first pole core II-5-3, a first coil II-5-2, and a first magnetic shielding sleeve II-5-1. The first pole core II-5-3 is a block structure, with a predetermined number of turns of wire wound around its middle section to form the first coil II-5-2. The first pole core II-5-3 and the first coil II-5-2 together constitute the electromagnetic body of the first electromagnet II-5, used to generate the required magnetic field under energized conditions. A first magnetic shielding sleeve II-5-1 matching its shape is provided on the outside of the electromagnetic body. The magnetic shielding sleeve shields and confines the magnetic field to reduce the leakage of magnetic field lines and improve the directionality of the magnetic field.

[0041] As shown in Figures 7(a) and 7(b), the second electromagnet II-9 includes a second pole core II-9-1, a second coil II-9-2, and a second magnetic shielding sleeve II-9-3. The second pole core II-9-1 has a Z-shaped structure, with its long leg section serving as a winding section. A predetermined number of turns of wire are wound around its outer circumference to form the second coil II-9-2. The second pole core II-9-1 and the second coil II-9-2 together constitute the electromagnetic body of the second electromagnet II-9. A second magnetic shielding sleeve II-9-3, matching the shape of the electromagnetic body, is provided on the outer side of the electromagnetic body.

[0042] In this embodiment, both the first magnetic shielding sleeve II-5-1 and the second magnetic shielding sleeve II-9-3 are split structures, not integrally formed. Instead, they are composed of multiple sleeve components that are adapted to the local shape of the electromagnetic body. The sleeve components can be connected as a whole by welding, fixing with connectors or other means to meet the installation requirements under the condition of limited assembly space and facilitate disassembly and maintenance.

[0043] like Figure 9 As shown, the current input of the first electromagnet II-5 and the current input of the second electromagnet II-9 are both sinusoidal and have a preset phase difference. In this way, the upper and lower electromagnets can form an alternating magnetic field and magnetic field gradient that varies with time in the blade tip area, thereby generating periodic traction and disturbance to the magnetic nano lubricant, promoting its migration and wetting to the blade tip and the blade-chip contact interface.

[0044] The electromagnet pole core of this embodiment can adopt one of the following two structures: one is a rectangular cross-section pole core with ordinary flat-head pole surfaces at the ends; the other is a pole core with a pointed pole shoe structure at the ends; both pole cores can generate a time-varying magnetic field by passing an alternating current through an AC excitation coil.

[0045] Under the periodic perturbation of an alternating magnetic field, magnetic nanoparticles generate high-frequency microscale responses and disturbances at the liquid-solid interface, activating flow near the interface and promoting the renewal of the lubricating medium. At the same time, it induces pseudoplastic flow characteristics with shear thinning at the edge of the microdroplet, reducing the apparent viscosity and viscous resistance of the solid-liquid interface, thereby reducing the wetting / spreading resistance of the lubricating medium in the micro gap and enhancing its film-forming ability and anti-wear effect in the blade tip region.

[0046] Furthermore, the calculation method for alternating excitation current and magnetic field length is as follows: Let the number of turns of the excitation coil be... N The excitation current is an alternating current, and its instantaneous expression can be given as:

[0047]

[0048] in: This is the excitation current of the first electromagnet; This is the excitation current of the second electromagnet; , These are the peak currents of the two electromagnets, respectively. Angular frequency; The frequency of the alternating magnetic field; For phase, where .

[0049] Neglecting leakage flux and approximating that the core permeability is much greater than the air permeability, the magnetic field strength at the working air gap... It can be approximated as:

[0050] in, This is the working air gap length.

[0051] Correspondingly, the magnetic induction intensity in the air gap It can be represented as:

[0052] Right now:

[0053] Therefore, the electromagnet generates an alternating magnetic field in the working air gap, and its magnetic induction intensity changes periodically with time.

[0054] Furthermore, the suction power of the electrode core is calculated in the following way: (1) For a rectangular cross-section flat-top electrode core, under ideal conditions, the suction force at its air gap can be expressed as: When the pole end is a standard flat-top pole face and the pole cross-section is rectangular, let the width of the magnetic pole end face be... Thickness is Then the area of ​​action of the magnetic pole is: ; Under ideal conditions, the instantaneous electromagnetic attraction at the air gap It can be represented as:

[0055] in, air gap magnetic induction intensity is the vacuum permeability.

[0056] Neglecting leakage flux and core magnetic reluctance, the attractive force can be further approximated as:

[0057] in, This is the effective value of the excitation current.

[0058] (2) For the pointed pole shoe core, due to the magnetic flux converging effect in the pointed region, the attraction at its air gap can be expressed as:

[0059] in, This represents the effective working area at the tip of the pole shoe.

[0060] When considering the effects of tip leakage flux, edge diffusion, and local magnetic saturation, a correction factor can be introduced. The actual suction force can then be written as:

[0061] Furthermore, under alternating excitation conditions, the attraction force of the pointed pole shoe core can be approximated as:

[0062] in, The value of is related to the tip size of the pole shoe, the cone angle, the working air gap length, the degree of magnetic leakage, and the local saturation state.

[0063] In summary, the attraction of both rectangular cross-section flat-head pole cores and pointed pole shoe pole cores is positively correlated with excitation current, number of coil turns and effective area, and negatively correlated with working air gap length; among them, pointed pole shoe pole cores are more conducive to forming higher magnetic field strength and magnetic field gradient in local areas.

[0064] like Figure 5As shown, the micro-lubrication system IV includes an oil reservoir IV-1, a precision lubrication pump IV-2, a precision pneumatic pump IV-3, a pneumatic frequency generator IV-4, a gas pressure regulating filter IV-5, a flow regulating valve IV-7, and a nozzle IV-9. The oil reservoir IV-1 stores magnetic nano lubricant. The precision lubrication pump IV-2 is equipped with a lubricant micro-adjustment knob IV-8, and the precision pneumatic pump IV-3 is equipped with a gas micro-adjustment knob IV-6. Both the air and oil circuits are equipped with flow regulating valves IV-7 to adjust the gas flow rate and lubricant flow rate.

[0065] External gas enters the gas pressure regulating filter IV-5 through an external gas pipe, and after pressure regulation and filtration, it enters the pneumatic frequency generator IV-4 through the air inlet. The outlet of the pneumatic frequency generator IV-4 is connected to the precision pneumatic pump IV-3 through a pipeline. The oil reservoir IV-1 is located on the upper part of the system casing, and its outlet is connected to the precision lubrication pump IV-2. One end of the precision lubrication pump IV-2 is connected to one end of the precision pneumatic pump IV-3, so that the lubricant and gas are mixed internally to form a gas-liquid mixture. This gas-liquid mixture is delivered to the nozzle IV-9 through the gas-liquid mixture outlet through a pipeline. The nozzle IV-9 is fixed to the outside of the second support plate II-15.

[0066] The micro-lubrication system IV mixes external high-pressure compressed air with lubricant in the mixing channel to form a gas-liquid mixture, which is then atomized and accelerated at the outlet of nozzle IV-9. This allows the gas-liquid mixture to be directionally sprayed at a high jet speed to the tool-chip contact area, thereby achieving micro-lubrication supply to the cutting interface.

[0067] In addition, such as Figure 1 and Figure 2 As shown, CNC machine tool I includes a protective door I-1, an alarm light I-2, a machine tool spindle box I-3, a three-jaw chuck I-4, a cutting tool post I-5, a machine tool CNC system I-6, a feed mechanism I-7, etc. CNC machine tool I is existing equipment, and its specific structure will not be described in detail here.

[0068] like Figure 8 As shown, the turning system in this embodiment also includes a main controller, which is used to output alternating magnetic field control signals, two-dimensional ultrasonic vibration control signals, and micro-lubrication supply control signals. The alternating magnetic field control signals are amplified by the first magnetic field drive module and the second magnetic field drive module, respectively, and then applied to the first electromagnet II-5 and the second electromagnet II-9 to form an alternating magnetic field and magnetic field gradient in the tool tip region.

[0069] The two-dimensional ultrasonic vibration control signal is amplified by the first ultrasonic drive module and the second ultrasonic drive module, respectively, and then applied to the first ultrasonic transducer II-1 and the second ultrasonic transducer II-13 to drive the cutting tool to form a composite ultrasonic vibration in the horizontal and vertical directions. The micro-lubrication supply control signal acts on the lubrication supply module to control the delivery of magnetic nano-lubricant to the cutting tip area through nozzle IV-9, thereby realizing the synergistic effect of alternating magnetic field traction, two-dimensional ultrasonic slit opening, and magnetic nano-lubricant wetting.

[0070] As shown in Figures 10(a) and 10(b), during the turning process, relative motion occurs between the tool and workpiece III, resulting in chip formation. When an external magnetic field is applied to the area near the tool tip, magnetic lubricant droplets migrate along the magnetic field lines towards the tool-chip-workpiece III interface under the influence of the magnetic force, and locally accumulate near the tool rake face, thereby improving the fluid supply capacity of the cutting zone. When the tool is not separated by ultrasonic vibration, the contact between the tool rake face and the bottom of the chip is relatively tight, and the lubricant droplets mainly accumulate in the area near the tool tip, making it difficult for them to further enter the actual contact interface between the tool and the chip. At this time, the effect of the external magnetic field is mainly manifested as the directional attraction of the magnetic lubricant droplets and the enrichment effect near the interface.

[0071] When the cutting tool operates under the assistance of two-dimensional ultrasonic vibration, it generates periodic micro-amplitude vibrations in two directions, creating a momentary separation gap between the tool's rake face and the chip. This momentary separation breaks the original continuous and tight contact condition, providing a dynamic channel for lubricant droplets to enter the tool-chip interface. Simultaneously, under the influence of an external magnetic field, the magnetic lubricant droplets are further guided along the magnetic field lines into the aforementioned momentary separation region and spread within the interface, thus transforming the lubricant medium from being enriched on the outer side of the interface to directionally penetrating into the cutting zone. Therefore, the periodic separation effect generated by two-dimensional ultrasonic vibration and the directional driving effect of the external magnetic field on the magnetic lubricant droplets are coupled, effectively improving the lubricant's ability to enter the cutting zone, enhancing the lubrication and cooling effect at the tool's rake face-chip interface, and consequently reducing cutting friction, cutting heat, and tool wear.

[0072] like Figure 11 As shown, during the cutting process, the chips flow at high speed along the rake face, forming a local low-pressure zone near the tool tip. This induces the lubricating medium to flow towards the cutting interface under the influence of pressure difference. When an external gradient magnetic field is applied, the magnetic particles and base fluid in the magnetic lubricant are simultaneously driven by the magnetic field, transforming fluid transport from being induced by a single pressure difference to being driven by a coupling of pressure difference and magnetic force. At this point, the lubricating medium further penetrates along the tool rake face into the tool-chip contact area, forming enrichment and retention near the interface. This process helps to overcome the air barrier layer formed during high-speed cutting, improving the lubricating medium's ability to penetrate deep into the cutting zone, thereby enhancing interfacial lubrication, friction reduction, and cooling effects.

[0073] This embodiment constructs a macroscopic gradient magnetic field in the cutting zone, causing the magnetic nano-lubricant to generate a targeted traction force towards the tool tip region under the action of Kelvin magnetic volume force. This effectively counteracts the centrifugal shedding tendency caused by the high-speed rotation of workpiece III and the aerodynamic resistance caused by the airflow field in the cutting zone. This allows the lubricating medium to break through the air barrier layer and achieve forced wetting and directional transport from the inlet of the contact area to the key micro-area of ​​the tool tip, improving the efficiency and stability of the lubricant reaching the tool tip and the tool-chip interface.

[0074] This embodiment applies two-dimensional ultrasonic vibration to the cutting tool, causing the tool and chip to separate and re-contact at high frequency during the cutting process. This creates instantaneous openings and micro-gaps within the tool-chip closed interface, providing the necessary wetting space for the lubricant to enter the tool tip and the tool-chip contact area. Furthermore, within the time window of the gap, the magnetic field targeting and the interface periodic "pumping" effect work synergistically to enhance the directional penetration and replenishment of the lubricant into the tool tip micro-area, improving the efficiency and continuity of the lubricating medium entering the closed interface.

[0075] Example 2: This embodiment provides a control method for an alternating magnetic field ultrasonic-assisted micro-lubricant traction-impregnation turning system, using the turning system described in Embodiment 1, such as... Figure 12 As shown, it includes: First, preset parameters are input, including parameters for the alternating magnetic field generator, the ultrasonic vibration device, and the micro-lubrication system. Based on these preset parameters, the workpiece is machined, and a cutting force waveform signal is output by a force gauge during the machining process.

[0076] Then, the cutting force waveform is characterized and analyzed to determine whether the current parameter combination needs optimization. If no optimization is needed, the parameters are directly output; if optimization is needed, the excitation current, excitation frequency, and magnetic field amplitude parameters of the alternating magnetic field generator, the vibration frequency, amplitude, and phase parameters of the ultrasonic vibration device, and the lubricant flow rate, air supply pressure, and pulse frequency parameters of the micro-lubrication system are adjusted. After adjustment, it is further determined whether the optimization target is met; if not, the parameters are adjusted again and the turning process is repeated; if the target is met, the optimized parameters are output.

[0077] Furthermore, in the parameter optimization stage, the system adopts an adaptive closed-loop control method based on cutting force waveform feedback. The main controller first inputs initial control parameters to the alternating magnetic field generator, ultrasonic vibration device, and micro-lubrication system, and drives the system to perform turning operations. During the machining process, the force gauge collects the main cutting force, feed force, and back force signals in real time, forming corresponding cutting force waveforms. The main controller performs feature extraction and analysis on the cutting force waveforms to obtain the average value, peak value, fluctuation amplitude, and stability index of the cutting force, and compares them with the preset target range to determine whether the current machining state needs optimization and adjustment.

[0078] When the average cutting force is too high, the excitation current, excitation frequency, and magnetic field amplitude of the alternating magnetic field generator should be adjusted first to enhance the traction ability of the magnetic nano lubricant towards the tool tip area and the tool-chip contact interface. When the cutting force fluctuates greatly, the vibration frequency, amplitude, and phase parameters of the two-dimensional ultrasonic vibration device should be adjusted first to improve the high-frequency contact-separation state between the tool and the chip. When the cutting force peak is obvious or the overall stability is poor, the lubricant flow rate, air supply pressure, and pulse frequency of the micro-lubrication system should be adjusted first to improve the continuity of lubricant delivery and interface coverage.

[0079] Furthermore, when at least two of the average cutting force, fluctuation amplitude, and stability indicators simultaneously deviate from the preset target range, the main controller performs coordinated adjustments to the alternating magnetic field generator, ultrasonic vibration device, and micro-lubrication system to maintain dynamic matching between the alternating magnetic field traction effect, the two-dimensional ultrasonic slit-opening effect, and the micro-lubrication supply effect. The adjusted parameters are then reapplied to the system, and the cutting force waveform continues to be collected for feedback analysis, thus forming an adaptive closed-loop control process of "cutting force detection - feature analysis - individual or coordinated adjustment - re-feedback".

[0080] The control method in this embodiment constructs a closed-loop optimization process with preset parameters as input, cutting force waveform output by a force measuring instrument as feedback, and optimization of parameters of alternating magnetic field generator, ultrasonic vibration device, and micro-lubrication system as the core, thereby obtaining an optimized parameter combination that meets the processing performance requirements.

[0081] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system, characterized in that, It includes a composite energy field turning device and a micro-lubrication system, wherein the micro-lubrication system stores magnetic nano-lubricant; The composite energy field turning device includes an ultrasonic vibration device, an alternating magnetic field generator and a cutting tool, with the nozzle in the micro-lubrication system corresponding to one side of the cutting tool. The ultrasonic vibration device includes a first ultrasonic transducer and a second ultrasonic transducer that are perpendicular to each other. The cutter is installed at the ends of the first ultrasonic transducer and the second ultrasonic transducer. The first ultrasonic transducer and the second ultrasonic transducer together provide two-dimensional ultrasonic vibration. The alternating magnetic field generating device includes a first electromagnet and a second electromagnet, wherein the first electromagnet is installed obliquely above the cutter and the second electromagnet is installed horizontally below the cutter.

2. The alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 1, characterized in that, The first ultrasonic transducer and the second ultrasonic transducer are both mounted on the support base, wherein the first ultrasonic transducer is arranged along the Z direction and the second ultrasonic transducer is arranged along the X direction; A force gauge is installed at the bottom of the support base.

3. The alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 1 or 2, characterized in that, The cutting tool is installed perpendicular to the first ultrasonic transducer and is coaxially arranged with the second ultrasonic transducer.

4. The alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 1, characterized in that, The first electromagnet is set at an acute angle to the horizontal plane, and a pre-installed installation gap is reserved between the lower side of the first electromagnet and the top surface of the tool holder.

5. The alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 4, characterized in that, The gap between the second electromagnet and the bottom surface of the tool holder is smaller than the installation interval between the first electromagnet and the top surface of the tool holder.

6. The alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 1, 4, or 5, characterized in that, The first electromagnet and the second electromagnet each include a pole core, a coil, and a magnetic shielding sleeve. The coil is wound around the outer periphery of the pole core, and the magnetic shielding sleeve is wrapped around the pole core and the outside of the electromagnet.

7. The alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 6, characterized in that, The pole core of the first electromagnet has a block-shaped structure, while the pole core of the second electromagnet has a Z-shaped structure.

8. The alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 1, characterized in that, The composite energy field turning device is installed inside the CNC machine tool, and the CNC machine tool is equipped with a main controller. The ultrasonic vibration device is connected to the main controller via an ultrasonic drive module, and the alternating magnetic field generator is connected to the main controller via a magnetic field drive module.

9. The control method for the alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to any one of claims 1-8, characterized in that, include: The workpiece is turned based on preset parameters, and the cutting force waveform signal is output by the force measuring instrument during the machining process; The cutting force waveform is feature extracted and analyzed, and it is determined whether the current parameter combination needs to be optimized. If no optimization is needed, the parameters are directly output. If optimization is needed, the parameters of the alternating magnetic field generator, the ultrasonic vibration device, and the micro-lubrication system are adjusted respectively. After the optimization target is met, the optimized parameters are output.

10. The control method for the alternating magnetic field ultrasonic-assisted micro-lubricant traction impregnation turning system according to claim 9, characterized in that, The parameters of the alternating magnetic field generator include the alternating magnetic field current, frequency, and amplitude; the parameters of the ultrasonic vibration device include the ultrasonic vibration frequency, amplitude, and phase; and the parameters of the micro-lubrication system include the lubricant flow rate, air pressure, and pulse frequency.

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