A flow-type lapping and polishing machine and a lapping method

Abstract

The application provides a flow type grinding and polishing machine and a grinding method thereof, and belongs to the field of grinding and polishing equipment. The grinding and polishing machine comprises a rack, a grinding groove mounted on the rack through damping springs, a variable frequency vibration motor mounted on the grinding groove, and a PLC closed loop control unit. The inner wall of the grinding groove is lined with a polyurethane wear-resistant lining, and the lining is integrally formed with a partitioned independent aeration unit. The aeration unit is composed of four mutually isolated annular pressure stabilizing cavities, namely an outer ring, an inner ring, a middle ring and an included angle. Each cavity is provided with an aeration hole with a specific inclined direction, and an arc-shaped flow guide groove following the material flow direction is processed at the hole opening. The device can complete the processing from burr removal to sub-micron ultra-precision polishing. The application breaks through the limitation of traditional vibration grinding machines which only rely on mechanical vibration parameter regulation effect, has high bubble utilization rate, good processing consistency, and can obtain the ultra-smooth surface required for precision machining.

Description

Technical Field

[0001] This invention relates to the field of grinding and polishing equipment technology, specifically to a flow grinding and polishing machine and grinding method. Background Technology

[0002] Grinding and polishing machines are currently one of the mainstream equipment used in industry for surface finishing of parts. The basic working process is as follows: a vibrating motor drives the grinding tank to generate high-frequency vibration, and the abrasive and the workpiece in the tank move relative to each other. Through collision, rolling and micro-cutting, the abrasive achieves deburring, rounding and surface strengthening on the workpiece surface.

[0003] However, traditional vibratory grinding machines have significant shortcomings. Their grinding effect is almost entirely determined by the frequency, amplitude, and excitation force of the vibratory motor, resulting in a limited range of control. This makes it difficult to simultaneously achieve the high material removal rate required for roughing and the low-damage surface quality required for finishing on the same machine. Furthermore, under the combined effects of gravity and vibration inertia, dead zones and sedimentation of the abrasive material within the tank easily occur, leading to poor processing consistency across different parts of the workpiece.

[0004] To address the aforementioned issues, several patents have proposed technical approaches that utilize microjets generated by bubble collapse to assist in polishing. For example, Chinese utility model patent CN204525190U discloses an ultrasonic-assisted three-phase abrasive flow polishing device. This device mounts an ultrasonic generator above the three-phase abrasive flow channel, using ultrasound to compress and collapse bubbles in the microbubble-containing medium, generating micro-shock waves that accelerate the downward movement of abrasive particles, thereby improving polishing efficiency. Patent CN204525193U discloses an ultrasonic polishing device utilizing a gas-liquid-solid three-phase abrasive flow. It improves the uniformity of bubble distribution on the workpiece surface by using a circumferentially arranged airflow in conjunction with an ultrasonic bubble generator. Chinese invention patent CN114473880A describes an ultrasonic-assisted fluid cavitation polishing device. This device incorporates a cavitation inducer in the flow loop to generate bubbles as the fluid flows through. Simultaneously, an ultrasonic generator moves outside the component to enhance cavitation intensity, utilizing the high-energy microjets generated by bubble collapse to polish the surface.

[0005] A closer analysis reveals a common characteristic of the aforementioned existing technologies: bubble generation relies on ultrasonic cavitation, representing a passive generation method. This approach has two inherent limitations. First, the location, quantity, and size of the bubbles are constrained by both the ultrasonic field parameters and the characteristics of the liquid medium, making it difficult to independently control different regions within the flow field. Second, ultrasonic cavitation requires a liquid medium, while the working environment of a vibratory mill is a flow field dominated by solid abrasives. These fundamental physical differences prevent the direct application of these technologies to vibratory milling equipment.

[0006] Based on this, there is an urgent need in the field to develop a new type of grinding equipment that can integrate an independent and controllable active aeration system into a vibratory grinding machine, so that the bubble parameters and vibration parameters can be independently controlled and coordinated, thereby achieving flexible processing of the entire process from rough grinding and deburring to submicron-level ultra-fine polishing on the same machine. Summary of the Invention

[0007] (a) Technical problems to be solved The present invention aims to provide a flow-type grinding and polishing machine and a corresponding grinding method. By directly integrating a multi-zone independent and controllable aeration system into the wear-resistant lining of the vibratory grinder, the air bubbles become a core medium that can actively regulate the shear force and grinding force of the grinding flow field, thereby breaking through the technical bottleneck of traditional vibratory grinders.

[0008] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution.

[0009] A flowing grinding and polishing machine includes a frame, a grinding tank mounted on the frame via multi-stage damping springs, a variable frequency adjustable vibration motor disposed on the grinding tank, and a PLC closed-loop control unit that is controllably connected to the vibration motor and the separately aerated units in the following sections. The inner wall of the grinding tank is lined with a wear-resistant lining.

[0010] The wear-resistant liner has an integrally formed partitioned independent aeration unit inside. This partitioned independent aeration unit contains four independent and completely isolated annular pressure-stabilizing air chambers, namely: an outer annular air chamber arranged on the outer side wall of the grinding tank, an inner annular air chamber arranged on the inner side wall of the grinding tank, a middle annular air chamber arranged on the bottom of the grinding tank, and an angled annular air chamber arranged at the included angle on the outer side of the bottom of the grinding tank.

[0011] As a preferred embodiment, the outer annular air chamber is provided with a plurality of aeration holes inclined toward the inside of the tank along its circumference, and the axis of these aeration holes is inclined horizontally at 15° toward the inside of the tank.

[0012] As a preferred embodiment, the inner annular air chamber is provided with a plurality of aeration holes inclined toward the inward direction along its circumference, and the axis of these aeration holes is inclined horizontally at 15° toward the outward side of the tank.

[0013] As a preferred embodiment, the middle annular air chamber is provided with multiple aeration holes that penetrate vertically upward through the wear-resistant liner along the bottom of the tank.

[0014] As a preferred embodiment, the included-angle annular air chamber is provided with a plurality of aeration holes that extend obliquely upward at 45° through the wear-resistant lining along the included-angle direction of the outer side of the tank bottom.

[0015] As a preferred embodiment, each of the above-mentioned aeration holes is provided with an arc-shaped guide groove at the outlet of the inner surface of the wear-resistant liner; the inlet end of the arc-shaped guide groove is connected to the outlet of the aeration hole, the extension direction of the groove body is consistent with the projection direction of the axis of the aeration hole on the inner surface of the wear-resistant liner, and the outlet end of the arc-shaped guide groove points to the mainstream material circulation direction of the grinding tank.

[0016] As a preferred embodiment, the vibration motor adopts a double eccentric block structure, with a frequency conversion adjustment range of 0-50Hz steplessly adjustable, an amplitude adjustment range of 0-5mm, and an excitation force adjustment range of 0-100%.

[0017] As a preferred embodiment, the wear-resistant lining is made of polyurethane, and the four annular pressure-stabilizing air chambers of the partitioned independent aeration unit are integrally embedded during the casting and molding of the polyurethane wear-resistant lining. The grinding groove can be an annular groove, a U-shaped groove, or a straight groove. The four annular pressure-stabilizing air chambers of the partitioned independent aeration unit can be arranged continuously along the circumference of the grinding groove or arranged in segments along the length direction.

[0018] As a preferred embodiment, the PLC closed-loop control unit has three pre-stored vibration parameter and aeration parameter linkage modes corresponding to the rough grinding and deburring stage, the medium grinding and homogenization stage, and the ultra-fine polishing stage, respectively: In the coarse grinding and deburring mode, the vibrating motor operates at a frequency of 30-50Hz and an amplitude of 3-5mm. At the same time, the outer ring annular air chamber and the included angle annular air chamber are opened to carry out high-flow aeration. By coordinating the control of aeration pressure and flow rate, the generated bubble particle size is mainly distributed in the range of 20-50μm. In the medium grinding homogenization mode, the vibrating motor operates at a frequency of 20-30Hz and an amplitude of 2-3mm. At the same time, the middle ring annular air chamber is opened to perform uniform aeration throughout the entire area. By coordinating the control of aeration pressure and flow rate, the generated bubble particle size is mainly distributed in the range of 10-30μm. In the ultra-fine polishing mode, the vibration motor operates at a frequency of 10-20Hz and an amplitude of 0.5-1.5mm, while the inner ring air chamber is opened for small-flow precision aeration. By coordinating the control of aeration pressure and flow rate, the generated bubble particle size is mainly distributed in the range of 5-20μm.

[0019] The present invention also provides a flow-type grinding and polishing method, which employs the flow-type grinding and polishing machine described in any of the above claims, and includes the following steps: Rough grinding and deburring step: The workpiece is clamped in the grinding tank, and the vibration motor is controlled by the PLC closed-loop control unit to run at a frequency of 30-50Hz and an amplitude of 3-5mm to form a strong collision and tumbling flow field; at the same time, the outer ring annular air chamber and the included angle annular air chamber are opened, and the aeration pressure and flow rate are adjusted so that the aeration holes generate large-diameter bubbles with a particle size mainly distributed in the range of 20-50μm under the shearing action of the strong collision and tumbling flow field. The micro-jet generated by the collapse of the bubbles cooperates with the collision of the abrasive to remove the burrs on the surface of the workpiece.

[0020] Medium grinding homogenization step: The PLC closed-loop control unit controls the vibration motor to run at a frequency of 20-30Hz and an amplitude of 2-3mm to form a medium-intensity rolling flow field; at the same time, the outer ring annular air chamber and the included angle annular air chamber are closed, and the middle ring annular air chamber is opened. The aeration pressure and flow rate are adjusted so that the aeration holes generate medium-sized bubbles with a particle size mainly distributed in the range of 10-30μm under the shearing action of the medium-intensity rolling flow field. The bubble micro-jet partially replaces the collision force of hard abrasive to achieve homogenization grinding.

[0021] Ultra-fine polishing step: The PLC closed-loop control unit controls the vibration motor to run at a frequency of 10-20Hz and an amplitude of 0.5-1.5mm to form a smooth and flexible rolling flow field; at the same time, the middle ring annular air chamber is closed and the inner ring annular air chamber is opened, and the aeration pressure and flow rate are adjusted so that the aeration holes generate micro-nano-scale bubbles with a particle size mainly distributed in the range of 5-20μm under the shearing action of the smooth and flexible rolling flow field. The nano-scale flexible micro-jet generated by the collapse of high-density micro-nano bubbles is used to perform non-destructive ultra-smooth polishing, so that the surface roughness of the workpiece reaches Ra≤0.05μm.

[0022] In addition to the basic functions of each of the aforementioned technical features, this invention also creates a synergistic effect of structure and function on three levels in the special high-energy flow field environment of vibration grinding.

[0023] The first level: Synergy between the vibratory flow field and zoned aeration. The basic function of the zoned independent aeration unit is to actively inject controllable bubbles into the grinding tank, so that the abrasive is uniformly suspended, and grinding is assisted by micro-jets of bubble collapse. When this aeration system is in a high-frequency, strong vibratory flow field driven by a vibratory motor, a bidirectional synergistic effect emerges between the two, which has not been revealed by existing technology. On the one hand, the periodic excitation of the vibratory motor forms an alternating pressure field in the abrasive flow. This pressure field actively induces and enhances the periodic compression and collapse of the injected bubbles. Compared with passive cavitation in static liquids, this bubble collapse process actively driven by mechanical vibration has significantly increased energy release intensity and frequency. On the other hand, the large number of microbubble groups injected by zoned aeration increases the compressibility of the abrasive fluid to a certain extent, changes the transmission path and dissipation mode of vibration energy in the abrasive, and allows the vibration force to penetrate the abrasive layer more uniformly to reach the workpiece surface, effectively reducing the ineffective frictional loss between abrasive particles.

[0024] The second level: the synergy between the inclined aeration holes and the arc-shaped guide channel under vibration conditions. Under static conditions, the specific inclination angle of the aeration holes only serves as a basic airflow guide. However, when the grinding tank is in a high-frequency vibration state, the airflow ejected from each aeration hole is injected tangentially along the main motion direction of the abrasive flow in that region. The velocity gradient between the airflow and the abrasive flow is minimized, and the bubbles are carried into the core region of the flow field by the abrasive flow the instant they are generated, without being repelled to the edge of the flow field due to velocity mismatch. On this basis, the introduction of the arc-shaped guide channel further enhances this synergistic effect. Specifically, the direction of the arc-shaped guide channel is consistent with the main motion direction of the abrasive flow in the region, and its arc surface structure provides a low-resistance guiding path for the abrasive flow. When the abrasive flow flows at high speed over the surface of the guide channel, the convergent geometry of the channel guides and constrains the high-density abrasive flow near the wall, so that the newly formed bubbles are immediately enveloped and carried by the adjacent main motion direction line of the abrasive flow after leaving the aeration hole, and smoothly merge into the core region of the flow field. This structure effectively prevents bubbles from escaping directly due to buoyancy or abrupt changes in streamlines. The inclined aeration holes provide the conditions for tangential injection, while the arc-shaped guide grooves provide the conditions for streamline guidance and constraint. Together, under vibration conditions, they complete the entire chain control of bubbles from directional injection and flow field guidance to merging into the mainstream, increasing the effective utilization rate of bubbles in the grinding flow field from less than 20% in the traditional structure to over 85%.

[0025] The third level: closed-loop linkage of vibration parameters and zoned bubble parameters. The PLC closed-loop control unit incorporates vibration frequency, amplitude, and aeration pressure and flow rate of each zone into a unified closed-loop control loop, and presets linkage control modes for the three process stages of rough grinding and deburring, medium grinding and homogenization, and ultra-fine polishing. In the rough grinding stage, high-frequency large-amplitude vibration and large-diameter bubbles in the outer ring and included-angle air chamber work together to form a superimposed removal effect of mechanical collision and bubble collapse microjets; in the medium grinding stage, medium-frequency medium-amplitude vibration and medium-diameter bubbles in the middle ring air chamber cooperate with each other, and bubble collapse microjets partially replace the direct collision of hard abrasives, maintaining removal efficiency while suppressing the generation of surface micro-scratches; in the ultra-fine polishing stage, low-frequency small-amplitude vibration provides a low-shear stable residence environment for micro-nano bubbles generated in the inner ring air chamber, and bubble collapse flexible microjets undertake the main material removal function, ultimately obtaining submicron-level surface quality.

[0026] (III) Beneficial Effects Compared with the prior art, the present invention has the following beneficial effects: First, by integrally casting four independent and completely isolated annular pressure-stabilizing air chambers into the wear-resistant lining of the grinding tank, active, zoned, and independent control of the location, quantity, and particle size of bubble generation within the vibratory grinding flow field is achieved. This is fundamentally different from the existing technology that relies on the ultrasonic cavitation effect to passively generate bubbles, overcoming the inherent limitation of the difficulty in precisely controlling passively cavitated bubbles in the vibratory grinding solid abrasive flow environment.

[0027] Secondly, by combining the specific tilt angle of the aeration holes with the arc-shaped guide groove, the airflow is injected at a tangential angle close to the main direction of the abrasive flow. The guide groove then streamlines the bubbles, confining them within the mainstream direction of the abrasive flow, successfully overcoming the problem of bubbles escaping from the grinding zone due to buoyancy. Tests show that the effective utilization rate of bubbles in the grinding flow field has increased from less than 20% in the traditional structure to over 85%, significantly improving the energy utilization efficiency of bubble-assisted grinding.

[0028] Third, by incorporating vibration frequency, amplitude, and aeration pressure and flow rate of each zone into a unified closed-loop control circuit through a PLC closed-loop control unit, a linkage control architecture for vibration parameters and zone bubble parameters was established. The equipment requires no changes to its mechanical structure; simply by switching parameters, it can sequentially complete the entire processing flow within the same grinding tank, including rough grinding and deburring, medium grinding and homogenization, and submicron-level ultra-fine polishing (Ra≤0.05μm), achieving integrated process convergence from burr removal to ultra-smooth surface processing.

[0029] Fourth, this invention is an innovative integration of the steel frame and multi-stage damping spring load-bearing structure of the traditional vibratory grinding machine. While retaining the classic load-bearing structure, it integrates the multi-zone aeration unit into the wear-resistant liner. There is no redundant design, so it can be put into production directly and has a good industrialization foundation. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the overall structure of a flow-type grinding and polishing machine and grinding method according to an embodiment of this application.

[0031] Figure 2 This is a half-sectional view of the overall flow-type grinding and polishing machine and grinding method according to an embodiment of this application.

[0032] Figure 3 This is a schematic diagram of a wear-resistant liner in a flow-type grinding and polishing machine and grinding method according to an embodiment of this application.

[0033] Figure 4 This is an embodiment of the present application. Figure 3 Enlarged view of point A in the middle.

[0034] Figure 5 Examples of this application Figure 4 Enlarged view of point B in the middle.

[0035] Figure 6 This is an overall process flow diagram of a flow-type grinding and polishing machine and grinding method according to an embodiment of this application.

[0036] In the diagram: 1-frame, 2-grinding tank, 3-vibration motor, 21-wear-resistant liner, 22-independent aeration unit, 221-outer annular air chamber, 222-inner annular air chamber, 223-middle annular air chamber, 224-angled annular air chamber, 225-arc-shaped guide channel. Detailed Implementation

[0037] The following will refer to the appendix in the examples of this invention. Figures 1-6 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1: See Figures 1 to 6 This embodiment provides a flow-type grinding and polishing machine. Based on the classic load-bearing structure of a traditional vibratory grinding machine, the equipment integrates a multi-zone independent aeration system into the wear-resistant lining of the grinding tank, and realizes the linkage control of vibration parameters and zone bubble parameters through a PLC closed-loop control unit.

[0039] This mobile grinding and polishing machine includes a frame 1, a grinding tank 2, a variable frequency adjustable vibration motor 3, and a PLC closed-loop control unit. The frame 1 is a welded steel frame structure with sufficient rigidity and load-bearing capacity. The grinding tank 2 is suspended above the frame 1 by multi-stage damping springs. These damping springs support the overall weight of the grinding tank 2 while effectively isolating the high-frequency vibrations of the tank from the frame 1, reducing noise during operation and extending the service life of the mechanical structure.

[0040] The vibration motor 3 is fixedly installed at the bottom or side of the grinding tank 2, and is arranged coaxially with the grinding tank 2. In this embodiment, the vibration motor 3 is a variable frequency vibration motor with a double eccentric block structure. Its rated frequency adjustment range is steplessly adjustable from 0 to 50 Hz, the amplitude adjustment range is 0 to 5 mm, the excitation force adjustment range is 0 to 100%, and it is equipped with a 23-bit absolute encoder. The real-time control accuracy of the vibration parameters can reach ±0.5%, which provides a hardware foundation for subsequent millisecond-level synchronous linkage with bubble parameters.

[0041] The inner wall of the grinding tank 2 is fully covered with a wear-resistant liner 21. The wear-resistant liner 21 is made of polyurethane material, which has good wear resistance and a certain elastic buffering capacity. It can effectively resist the wear caused by long-term abrasive erosion and provide flexible protection when the workpiece accidentally collides with the tank wall.

[0042] The core innovative structure of this invention lies in the fact that the wear-resistant liner 21 has an integrally formed partitioned independent aeration unit 22 inside. This partitioned independent aeration unit 22 is completely embedded in the wall thickness of the polyurethane liner and is pre-embedded during the casting and molding of the wear-resistant liner. It forms an integral structure with the liner body without welding, leakage, or mechanical connection interface, thus fundamentally eliminating the hidden dangers of fatigue cracks and gas leakage that are prone to occur in traditional welded or bonded air chambers under long-term high-frequency vibration conditions.

[0043] The zoned independent aeration unit 22 is scientifically divided according to the three-dimensional spiral flow field characteristics of the annular groove of the vibratory grinder. It is divided into four completely isolated, independently supplied annular pressure-stabilized air chambers, with no gas flow channels between them. The specific arrangement of the four air chambers is as follows: Outer annular air chamber 221: Located on the outer wall of the grinding tank 2, corresponding to the outer high-speed tumbling zone covering the flow field. This air chamber has multiple aeration holes evenly spaced along its circumference, inclined inwards towards the tank. The axes of these aeration holes are horizontally inclined at 15° towards the inside of the tank. This inclination angle was determined through flow field analysis, ensuring that the ejection direction of the aeration airflow is essentially consistent with the main motion direction of the outer abrasive flow on the horizontal projection. This reduces the velocity difference between the airflow and the abrasive flow, facilitating rapid mixing of the gas and abrasive flow, thereby achieving high-flow-rate enhanced aeration in the outer region.

[0044] The inner annular air chamber 222 is located on the inner wall of the grinding tank 2, corresponding to the central recirculation zone covering the flow field. This air chamber has multiple aeration holes evenly spaced along its circumference, inclined inwards towards the tank. The axes of these aeration holes are horizontally inclined at 15° outwards from the tank. This arrangement allows the airflow to be injected obliquely into the central recirculation zone, and the injection angle is adapted to the characteristics of the low abrasive flow velocity and variable flow direction within the recirculation zone, creating favorable conditions for precision aeration.

[0045] The central annular air chamber 223 is located at the bottom of the grinding tank 2, corresponding to the core grinding zone that covers the flow field. This air chamber has multiple aeration holes along the bottom of the tank, which penetrate vertically upwards through the wear-resistant liner 21. Gas is injected vertically upwards from the bottom of the tank into the core area of ​​the abrasive flow. The core grinding zone bears the majority of the grinding workload. Uniform aeration throughout this area via the central air chamber directly controls the core quality of the grinding effect.

[0046] Angle-angled annular air chamber 224: Located at the outer corner of the bottom of the grinding tank 2, corresponding to the abrasive settling zone covering the flow field. This air chamber has multiple aeration holes along the outer corner of the tank bottom, which extend upwards at a 45° angle through the wear-resistant liner 21. The angled position is where abrasive particles most easily accumulate under the influence of gravity and vibration. Injecting high-pressure airflow from this location directly impacts and agitates the accumulated abrasive layer, effectively breaking up the abrasive settling layer and achieving forced suspension and circulation of the abrasive throughout the tank.

[0047] In this embodiment, the grinding tank 2 adopts an annular groove structure. The four annular pressure-stabilizing air chambers are continuously arranged along the circumference of the annular groove, forming a complete closed-loop air chamber system. In other embodiments, the grinding tank 2 can also adopt a U-shaped groove or a straight groove. In this case, the four annular pressure-stabilizing air chambers of the partitioned independent aeration unit 22 are arranged in segments along the length of the tank to meet the processing requirements of different types of workpieces.

[0048] The generation and control of bubble size are not solely determined by the aperture of the aeration holes, but rather by the combined regulation of aeration pressure, flow rate, and the mechanical shear force of the flow field. Specifically, the outlet aperture of the aeration holes in each of the aforementioned annular pressure-stabilizing air chambers is the fundamental factor determining the initial bubble size. During operation, the air supply system inputs compressed gas into each air chamber. Under pressure, the gas passes through the aeration holes to form an initial airflow. This airflow is dispersed and broken at the orifice by the high-intensity shear force of the vibrating abrasive flow in the area, ultimately forming a cluster of microbubbles dispersed in the abrasive. The PLC system, through precision pressure regulating valves and thermal mass flow controllers, accurately adjusts the gas pressure and flow rate entering each air chamber, thereby stably controlling the bubble size generated in the air chamber within the target range under certain flow field conditions.

[0049] To address the varying requirements for bubble size at different process stages, the aeration orifice diameters of each air chamber were pre-set differently. Specifically: the outer annular air chamber 221 and the included-angle annular air chamber 224 used in the coarse grinding stage have aeration orifice diameters set to 20–50 μm, facilitating the formation of larger bubbles during high-flow-rate aeration; the middle annular air chamber 223 used in the intermediate grinding stage has an orifice diameter set to 10–30 μm, conducive to generating uniform medium-sized bubbles; and the inner annular air chamber 222 used in the ultra-fine polishing stage has an orifice diameter set to 5–20 μm, suitable for generating micro- and nano-sized bubbles. In actual operation, the final bubble size is not solely determined by the orifice diameter; it also requires adjustment of aeration pressure and flow rate for control, enabling proactive and precise adjustment of bubble size in different regions.

[0050] To effectively improve the actual utilization rate of bubbles in the grinding flow field, this invention provides an arc-shaped guide groove 225 at the outlet of each aeration hole located on the inner surface of the wear-resistant liner 21. The arc-shaped guide groove 225 connects to the outlet of the aeration hole at its inlet end, and its extension direction is consistent with the projection direction of the axis of the aeration hole onto the inner surface of the wear-resistant liner 21. Furthermore, the outlet end of the arc-shaped guide groove 225 points towards the mainstream material circulation direction of the grinding tank 2. Specifically, in this embodiment, the arc-shaped guide groove 225 has a depth of 2mm and a width of 3mm. Its facing end (the end facing the direction of the incoming abrasive flow) has a rounded transition to reduce fluid resistance and guide the abrasive smoothly into the guide groove area; the back end (the end facing the direction of the outgoing abrasive flow) smoothly connects to the outlet of the aeration hole without any steps or abrupt changes.

[0051] As is known to those skilled in the art, under the drive of an eccentric vibrating motor, the material in the annular grinding tank will form an integral spiral tumbling motion around the circumference of the tank. This main motion direction can be uniquely determined by the rotation direction of the vibrating motor and the phase of the eccentric block. Therefore, the orientation of the arc-shaped guide channel is set based on this macroscopic circumferential motion direction. Specifically, in this embodiment, when the vibrating motor is set to clockwise excitation, the main motion direction of the material in the grinding tank is clockwise, so the arc-shaped guide channel in the outer ring area is set as a clockwise arc. This setting based on known physical laws can be uniquely determined without complex flow field testing.

[0052] When the grinding tank 2 operates under high-frequency vibration, the extension direction of the arc-shaped guide channel 225 is consistent with the projection direction of the aeration hole axis on the inner lining surface. Therefore, the airflow / bubbles discharged from the aeration holes are confined within the channel of the guide channel the instant they leave the orifice. The arc-shaped structure of the guide channel provides a low-resistance path for the adjacent abrasive flow, allowing newly generated bubbles to be carried away by the abrasive flow along the channel direction and smoothly merge into the core area of ​​the flow field, avoiding direct upward escape due to buoyancy or abrupt changes in streamlines. Actual measurements show that after setting this arc-shaped guide channel, the proportion of bubbles that can be effectively transported and participate in the grinding operation can be increased from less than 20% in the traditional structure to more than 85%.

[0053] Each annular pressure-stabilizing gas chamber is independently equipped with a high-pressure gas supply line, which is connected to a dedicated set of precision pressure regulating valves and thermal mass flow controllers via independent stainless steel high-pressure gas pipes. Each set of precision pressure regulating valves and thermal mass flow controllers constitutes an independent gas parameter control channel, allowing for completely independent closed-loop control of the aeration pressure and aeration flow rate of that gas chamber. The operating parameters of the four gas chambers do not interfere with each other, fundamentally solving the defect of traditional single-channel aeration that cannot adapt to the zoning characteristics of vibrating flow fields.

[0054] The PLC closed-loop control unit is electrically connected to the frequency converter driver of the vibrating motor 3, the proportional control terminals of the precision pressure regulating valves corresponding to each air chamber, and the setting and feedback terminals of each thermal mass flow controller. During operation, the PLC closed-loop control unit receives real-time frequency and phase signals from the 23-bit absolute encoder of the vibrating motor 3, as well as real-time mass flow signals from each thermal mass flow controller. Based on the target flow rate value under the preset process mode, the PLC calculates and outputs control signals to the corresponding precision pressure regulating valves using its built-in PID algorithm, adjusting the valve opening in real time to form a closed-loop control of the aeration flow rate in each air chamber, thereby keeping the deviation between the actual operating parameters and the preset parameters within a very small range.

[0055] This invention further establishes a control logic that coordinates vibration parameters with multi-zone bubble parameters. The PLC control unit's internal memory stores three sets of parameter linkage modes corresponding to the three process stages: rough grinding and deburring, medium grinding and homogenization, and ultra-fine polishing. The operator only needs to select the target process on the control interface, and the system will automatically call the preset parameters and complete the synchronous control of all air chambers and vibration motors. The specific process is detailed below.

[0056] I. Coarse grinding and deburring stage The workpiece to be processed is clamped in a predetermined position within the grinding tank 2 using a multi-station flexible clamping unit, and an appropriate amount of abrasive is added to the tank. The operator selects the "rough grinding and deburring" mode on the PLC control interface, and the PLC closed-loop control unit then calls the pre-stored rough grinding parameter linkage mode.

[0057] In this mode, the PLC closed-loop control unit outputs control commands to the frequency converter driver of the vibration motor 3, causing the vibration motor 3 to operate in a high frequency range of 30-50Hz, with the amplitude set to 3-5mm and the excitation force adjusted to a higher output level. Under these parameters, a strong collision and tumbling flow field is formed in the grinding tank 2, resulting in high-energy relative motion and frequent collisions between the abrasive and the workpiece.

[0058] Simultaneously, the PLC closed-loop control unit sends commands to the air supply system, triggering the opening of precision pressure regulating valves corresponding to the outer annular air chamber 221 and the angled annular air chamber 224, while closing the air supply passages of the inner annular air chamber 222 and the middle annular air chamber 223. Based on a preset flow-pressure curve, the system adjusts the air supply pressure and flow rate of these two air chambers, ensuring that the gas at the aeration hole outlet with a pore size of 20–50 μm is subjected to high shear force from a strong vibration flow field and effectively dispersed into large-diameter bubbles with a particle size mainly distributed in the 20–50 μm range. The high-flow-rate aeration of the outer air chamber enhances the abrasive activity in the outer high-speed tumbling zone, while the oblique aeration at the bottom of the angled air chamber eliminates the dead zone of abrasive settling and accumulation at the bottom of the tank, achieving forced uniform suspension of the abrasive throughout the entire tank.

[0059] During this stage, high-frequency vibrations of 30–50 Hz create a periodic alternating pressure field within the abrasive stream. This pressure field actively induces and enhances the batch compression and collapse of the generated large-diameter bubbles, with an effect far exceeding the passive cavitation effect formed by the acoustic field in static liquids. The high-intensity microjets released instantaneously by the bubble collapse and the mechanical collision of the abrasive with the workpiece surface produce a synergistic effect, efficiently removing defects such as burrs, flash, and oxide scale from the workpiece surface. Comparative tests show that the burr removal efficiency in this stage is more than 50% higher than that of traditional single-mechanical vibration grinding machines.

[0060] II. Medium grinding homogenization stage After the coarse grinding process is completed, the PLC closed-loop control unit automatically switches to the medium grinding homogenization mode according to the preset program or operator instructions.

[0061] In this mode, the PLC closed-loop control unit adjusts the operating parameters of the vibration motor 3 to a medium frequency range of 20-30Hz, reducing the amplitude to 2-3mm to form a medium-intensity rolling flow field. Simultaneously, the PLC closed-loop control unit closes the air supply passages of the outer annular air chamber 221 and the included-angle annular air chamber 224, and instead opens the middle annular air chamber 223. By adjusting the aeration pressure and flow rate, the gas, under the combined action of the aeration holes with a pore size of 10-30μm and the current flow field shear force, generates medium-sized bubbles with a particle size mainly distributed in the 10-30μm range.

[0062] The annular air chamber 223, located at the bottom of the tank, has aeration holes that penetrate vertically upwards through the wear-resistant liner. Medium-sized bubbles disperse uniformly upwards from the bottom of the tank, penetrating the entire abrasive flow layer and achieving uniform aeration throughout the core grinding zone. In a moderate-intensity rolling flow field, the uniformly distributed medium-sized bubbles can collapse stably, releasing moderate microjets. This microjets effectively replace some of the direct mechanical collisions between hard abrasives and the workpiece surface, ensuring uniform material removal and maintaining processing efficiency while mechanistically reducing defects such as surface micro-scratches and stress concentrations caused by hard collisions. Tests show that the uniformity of surface roughness across different parts of the workpiece is improved by 80% compared to traditional processes.

[0063] III. Ultra-fine polishing stage After the intermediate grinding process is completed, the PLC closed-loop control unit automatically switches to the ultra-fine polishing mode.

[0064] In this mode, the PLC closed-loop control unit adjusts the operating parameters of the vibration motor 3 to a low frequency range of 10–20 Hz, further reducing the amplitude to 0.5–1.5 mm, forming a smooth and flexible rolling flow field. The abrasive motion in the flow field is mainly characterized by low-energy rolling and sliding friction, minimizing macroscopic mechanical collision forces. In conjunction with this, the PLC closed-loop control unit closes the air supply passage of the middle annular air chamber 223 and opens the inner annular air chamber 222. By precisely controlling the aeration pressure and flow rate, the gas generates micro-nano-scale bubbles with a particle size mainly distributed in the 5–20 μm range through aeration holes with a pore size of 5–20 μm and under the current low-shear flow field.

[0065] The inner annular gas cavity 222 is arranged on the inner wall of the grinding tank, corresponding to the central recirculation zone of the covered flow field. This region has a low flow velocity and low shear force, providing an ideal flow field environment for the stable generation and residence of micro / nano bubbles. Micro / nano bubbles are characterized by large specific surface area, long residence time in water, and highly concentrated collapse energy.

[0066] Under low-frequency stable vibration of 10–20 Hz, high-density micro- and nano-bubble clusters continuously and uniformly collapse near the workpiece surface, releasing flexible microjets of nanoscale energy. These microjets perform micro-removal and ultra-smooth finishing on the workpiece surface in a non-contact manner, effectively suppressing the generation of mechanical scratches. After this stage of treatment, the workpiece surface roughness can reach a precision-grade smooth surface with Ra ≤ 0.05 μm.

[0067] Comparative experimental cases To verify the technical effect of the present invention, the following three types of equipment were used to process small 304 stainless steel workpieces of the same batch, with a processing time of 30 minutes for each: Comparative Example 1: A traditional vibratory grinder, equipped only with a vibratory motor, without an aeration system, with a vibration frequency of 40Hz, an amplitude of 4mm, and abrasive material of brown corundum particles with a particle size of 0.5mm.

[0068] Comparative Example 2: The control equipment was a single-channel aeration device added to the bottom of a traditional vibratory mill. The aeration holes were vertically upward, without partitions or guide channels. The vibration frequency was 40Hz, the amplitude was 4mm, and the aeration flow rate was 15L / min. The abrasive was the same as that in Comparative Example 1.

[0069] Example: The flow grinding and polishing machine described in Example 1 of the present invention adopts a coarse grinding mode, with a vibration frequency of 40Hz and an amplitude of 4mm. The outer ring annular air chamber 221 and the included angle annular air chamber 224 are opened, and the total aeration flow rate is 15L / min. The abrasive is the same as that in Comparative Example 1.

[0070] All experimental groups used the same workpiece clamping method, maintaining a consistent abrasive-to-workpiece volume ratio during machining. The test results are shown in the table below: The apparent utilization rate of bubbles is calculated as (volume of bubbles involved in effective grinding / total volume of injected bubbles) × 100%, determined by high-speed imaging and image analysis. Comparative Example 1 had no bubble injection and was therefore not calculated.

[0071] The above comparative experiments show that, under the same vibration parameters and total aeration flow rate, the present invention can reduce the surface roughness of the workpiece to Ra 0.12μm through the synergistic effect of the partitioned independent aeration unit and the arc-shaped guide channel, which is about 66% better than the traditional vibratory grinding machine.

[0072] Furthermore, by employing the three-stage linkage mode of this invention to perform full-process machining on the same batch of workpieces, the surface roughness of the workpieces after machining reaches Ra 0.04–0.06 μm. In contrast, even with an extended processing time of 90 minutes, the device in Comparative Example 2 only achieves a minimum surface roughness of Ra ≈ 0.18 μm, failing to break through the 0.1 μm bottleneck. These results demonstrate that this invention can stably achieve sub-micron level precision polishing, representing a significant technological advancement compared to existing vibratory grinding equipment.

[0073] The above embodiments illustrate the present invention using an annular groove structure as an example, but the scope of protection of the present invention is not limited thereto. For U-shaped groove or straight groove grinding grooves, the four annular pressure-stabilizing air chambers of the partitioned independent aeration unit are arranged in segments along the length of the groove. Each segment still maintains an independent air supply pipeline and independent control function. Different parameters can be set between each segment as needed to adapt to the processing requirements of slender workpieces. In addition, a closed-loop purification unit can be added as needed to purify and recycle the dust-laden gas discharged during the grinding process or to achieve standard emissions, further meeting the requirements of green manufacturing.

[0074] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flowing grinding and polishing machine, comprising a frame (1), a grinding tank (2) mounted on the frame (1) via multi-stage damping springs, a variable frequency adjustable vibration motor (3) mounted on the grinding tank (2), and a PLC closed-loop control unit connected to both the vibration motor (3) and the following partitioned independent aeration unit (22), wherein the inner wall of the grinding tank (2) is lined with a wear-resistant inner lining (21), characterized in that: The wear-resistant liner (21) has an integrally molded partitioned independent aeration unit (22) inside. The partitioned independent aeration unit (22) includes four independent and completely isolated annular pressure-stabilizing air chambers, namely: an outer annular air chamber (221) located on the outer side wall of the grinding tank (2), an inner annular air chamber (222) located on the inner side wall of the grinding tank (2), a middle annular air chamber (223) located at the bottom of the grinding tank (2), and an angled annular air chamber (224) located at the outer corner of the bottom of the grinding tank (2).

2. The flowing grinding and polishing machine according to claim 1, characterized in that, The outer annular air chamber (221) has a plurality of aeration holes inclined toward the inside of the tank along its circumference, and the axis of the aeration holes is inclined horizontally at 15° toward the inside of the tank.

3. The flowing grinding and polishing machine according to claim 1, characterized in that, The inner annular air chamber (222) has a plurality of aeration holes inclined toward the inside of the groove along its circumference, and the axis of the aeration holes is inclined horizontally at 15° toward the outside of the groove.

4. The flowing grinding and polishing machine according to claim 1, characterized in that, The annular air chamber (223) in the middle ring is provided with a plurality of aeration holes that penetrate vertically upward through the wear-resistant liner (21) along the bottom of the tank.

5. The flowing grinding and polishing machine according to claim 1, characterized in that, The included-angle annular air chamber (224) has multiple aeration holes that extend obliquely upward at 45° through the wear-resistant lining (21) along the included-angle direction of the outer side of the tank bottom.

6. The flow-type grinding and polishing machine according to any one of claims 2-5, characterized in that, Each aeration hole is provided with an arc-shaped guide groove (225) at the outlet of the inner surface of the wear-resistant liner (21). The inlet end of the arc-shaped guide groove (225) is connected to the outlet of the aeration hole, and the extension direction of the groove is consistent with the projection direction of the axis of the aeration hole on the inner surface of the wear-resistant liner (21). The outlet end of the arc-shaped guide groove (225) points to the mainstream material circulation direction of the grinding tank (2).

7. The flowing grinding and polishing machine according to claim 1, characterized in that, The vibration motor (3) is a double eccentric block vibration motor with a frequency range of 0-50Hz steplessly adjustable, an amplitude range of 0-5mm, and an excitation force adjustment range of 0-100%.

8. The flow-type grinding and polishing machine according to claim 1, characterized in that, The wear-resistant lining (21) is made of polyurethane material, and the four annular pressure-stabilizing air chambers of the partitioned independent aeration unit (22) are integrally implanted when the polyurethane wear-resistant lining is cast and molded; the grinding groove (2) is an annular groove, a U-shaped groove or a straight groove, and the four annular pressure-stabilizing air chambers of the partitioned independent aeration unit (22) are arranged continuously or in segments along the circumferential or length direction of the grinding groove.

9. A flow-type grinding and polishing method, employing the flow-type grinding and polishing machine as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Rough grinding to remove burrs: Control the vibration motor (3) to run at a frequency of 30-50Hz and an amplitude of 3-5mm, and open the outer ring annular air chamber (221) and the included angle annular air chamber (224) to remove burrs by using the collision of bubble collapse micro-jet with abrasive. Medium grinding homogenization: Control the vibration motor (3) to run at a frequency of 20-30Hz and an amplitude of 2-3mm, and open the middle ring annular air chamber (223) to use bubble micro-jet to partially replace the abrasive collision for homogenization grinding; Ultra-fine polishing: Control the vibration motor (3) to run at a frequency of 10-20Hz and an amplitude of 0.5-1.5mm, and open the inner ring annular air chamber (222) to polish using the micro-jet generated by the collapse of bubbles.

Images