A polishing device for large aspect ratio small holes with pulsating abrasive flow

Abstract

The present invention belongs to the field of ultra-precision machining, and specifically relates to a pulsating abrasive flow polishing device for small holes with a large depth-to-diameter ratio, comprising a moving part, a driving part, and a workpiece part; the moving part comprises a driving block and a reciprocating driving mechanism, the reciprocating driving mechanism being used to drive the driving block to reciprocate in the front-to-back direction; the driving part comprises a push rod and an ejection mechanism, the ejection mechanism being used to eject the push rod forward; the workpiece part comprises a fixture assembly and a material cylinder, the fixture assembly being used to clamp the workpiece, the material cylinder being used to store abrasive and to slide with the push rod, the material cylinder being located between the fixture assembly and the push rod, and corresponding to the positions of the fixture assembly and the push rod. The present invention is provided with structures such as a moving part, a driving part, and a workpiece part, which can realize high-speed intermittent abrasive supply, give the abrasive a high-speed energy, enhance the turbulent kinetic energy of the fluid, and thus improve the polishing effect.

Description

Technical Field

[0001] This invention belongs to the field of ultra-precision machining, specifically relating to a polishing device for a small hole with a large aspect ratio and a pulsating abrasive flow. Background Technology

[0002] Large-aspect-ratio small holes are widely used in aerospace, rail transportation, chemical industry, microelectronics, and medical and health fields, such as engine fuel nozzles, high and low pressure liquid nozzles, spinneret holes in spinneret molds, and needles in microelectronic dispensing machines. The machining accuracy and surface quality of these large-aspect-ratio small holes are related to the key performance of components. With the continuous development of advanced manufacturing technology, the performance requirements for products are becoming increasingly stringent. Even though some scholars have devoted themselves to improving the surface quality of deep small hole machining and avoiding secondary processing, the emergence of various special machining methods, such as laser processing and electrical discharge machining, still requires polishing to obtain precision deep small hole parts due to the inherent limitations of these methods.

[0003] Currently, there are various polishing methods for small holes with large aspect ratios, such as electrolytic polishing (electrochemical polishing) and abrasive flow machining. Electrolytic polishing utilizes the preferential dissolution of raised areas on the workpiece surface compared to recessed areas. However, this method requires the use of chemicals, thus raising significant environmental concerns, and the shape accuracy of the holes is difficult to guarantee. Electrolytic plasma polishing, developed based on this, uses a neutral salt solution as the polishing fluid. By increasing the electrode voltage, a complete gas layer is formed on the workpiece surface. The gas is then ionized to form plasma, generating complex plasma chemical reactions, and the resulting chemical reactants are removed by discharge. However, this method generates flocculent reactants after the neutral salt solution ionizes, which can easily clog the workpiece when polishing small holes with large aspect ratios. Abrasive flow machining is a non-traditional finishing technology that uses semi-fixed abrasive media to reciprocate and slide against complex surfaces to improve surface quality. It is widely used in high-end equipment in aerospace, medical, and rail transportation fields, and is also commonly used for finishing the internal and external cavities of certain special parts, such as irregular channels, slender holes, impellers, grooves, and slotted rings.

[0004] However, existing abrasive flow polishing devices also have some problems: for example, when machining small holes with a large depth-to-diameter ratio, the kinetic energy of the abrasive grains continuously weakens, resulting in unsatisfactory polishing effects on the latter half of the hole, leading to uneven and incomplete polishing. Furthermore, when machining small holes, the abrasive flow has a certain viscosity, often causing blockages as the abrasive cannot pass through the small holes.

[0005] To address the aforementioned problems, this invention proposes a polishing device for small holes with a large aspect ratio using a pulsating abrasive flow. By utilizing a high-speed, intermittent abrasive supply, the abrasive is given high-speed energy, enhancing the turbulent kinetic energy of the fluid and thus improving the polishing effect. At the same time, the intermittent polishing method allows for segmented polishing of the workpiece, which enables a more uniform polishing effect and makes it less prone to clogging when polishing small holes. Summary of the Invention

[0006] This invention addresses the problem of incomplete and uneven polishing of the inner wall of small holes with large aspect ratio using traditional abrasive flow. It proposes a polishing device for small holes with large aspect ratio using pulsating abrasive flow. The polishing device has a simple structure and can effectively improve the problem of incomplete and uneven polishing of the inner wall of small holes with large aspect ratio, achieving ultra-high precision polishing of the inner wall of small holes with large aspect ratio.

[0007] The present invention achieves the above objectives through the following technical solution: a polishing device for a large aspect ratio small hole with pulsating abrasive flow, comprising a moving part, a driving part, and a workpiece part;

[0008] The moving part includes a drive block and a reciprocating motion drive mechanism, the reciprocating motion drive mechanism being used to drive the drive block to reciprocate in the front-back direction;

[0009] The drive unit includes a push rod and a ejection mechanism, the ejection mechanism being used to eject the push rod forward.

[0010] The workpiece portion includes a clamping assembly and a material cylinder. The clamping assembly is used to clamp the workpiece, and the material cylinder is used to store abrasive and slides with the push rod. It is located between the clamping assembly and the push rod and corresponds to the position of the clamping assembly and the push rod.

[0011] The polishing device is configured such that, during the polishing process, the reciprocating drive mechanism drives the drive block to move backward, thereby activating the ejection mechanism. The activated ejection mechanism then drives the push rod to eject forward, causing the push rod to spray the abrasive in the material cylinder onto the fixture assembly, thus polishing the small holes of the workpiece through the abrasive.

[0012] Furthermore, the reciprocating motion drive mechanism is an electric ball screw module.

[0013] Furthermore, the ejection mechanism includes a reciprocating block, a blocking block, a connecting member, an ejection spring, a spring support block, and a drive part support base. The blocking block and the spring support block are fixedly mounted on the drive part support base. The connecting member is slidably mounted on the drive part support base. The push rod is mounted on the connecting member. The ejection spring is connected between the connecting member and the spring support block to push the connecting member towards the front end. The reciprocating block is slidably fitted onto the connecting member in the left-right direction. The reset spring is connected between the reciprocating block and the connecting member to drive the reciprocating block to reset.

[0014] The polishing device is configured such that, during the polishing process, the reciprocating drive mechanism drives the drive block to move backward, and the drive block drives the reciprocating block and connecting parts to move backward, so that the ejector spring is compressed. When the reciprocating block moves backward, it contacts the blocking block and is squeezed by the blocking block, so that the reciprocating block moves away from the drive block. When the reciprocating block moves to the state of being separated from the drive block, the ejector spring drives the connecting parts and push rod to be ejected forward, so that the push rod sprays the abrasive in the material cylinder onto the fixture assembly, and polishes the small hole of the workpiece through the abrasive.

[0015] Furthermore, the rear side of the reciprocating block is configured as an inclined surface or a circular arc surface, and the front side of the blocking block is configured as an inclined surface or a circular arc surface, with the rear side of the reciprocating block used to cooperate with the front side of the blocking block.

[0016] Furthermore, a second linear slide rail is provided on the drive part support base, and the bottom of the connector is connected to the second linear slide rail through a second slider.

[0017] Furthermore, a feeding port is provided on the upper side of the material cylinder.

[0018] Furthermore, the fixture assembly includes a first fixture and a second fixture. The first fixture has a first receiving cavity, the front of which is used to insert a workpiece, and the rear of which is used to insert the second fixture. The second fixture is used to abut against the front end of the workpiece and has a through hole corresponding to the position of a small hole on the workpiece. The fixture assembly is mainly for fixing the workpiece. The two fixtures directly fix the workpiece through limiting, ensuring consistency during processing.

[0019] Furthermore, the workpiece portion also includes a barrel connected to a second clamp for collecting the polished abrasive.

[0020] Furthermore, the material cylinder is connected to the first clamp via a connecting flange, the connecting flange is fitted with a connecting flange support frame, and the second clamp is fitted with a connecting clamp support seat.

[0021] When using this device for polishing, first start the electric ball screw module and feed the abrasive into the cylinder from above. By controlling the motor of the electric ball screw module, the drive block moves. After the drive block contacts the reciprocating block, it drives the reciprocating block to move. When the reciprocating block contacts the blocking block, it will retract inward due to the inclination. At the same time, during the movement of the motor, the connecting part will compress the ejector spring. When the drive block is not long enough to disengage from the reciprocating block, the ejector spring returns to its original state, thus giving the connecting block a forward thrust. The connecting part drives the push rod to push the abrasive, thereby achieving the effect of pulsating polishing.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The present invention is provided with a moving part, a driving part, a workpiece part and other structures, which can realize high-speed intermittent abrasive supply, give the abrasive a high-speed energy, enhance the turbulent kinetic energy of the fluid, and thus improve the polishing effect;

[0024] 2) The present invention has a simple structure, low cost, and strong applicability. The pulse intensity can be adjusted by changing the installation position of the spring support block. At the same time, the pulse frequency can also be changed by changing the stroke speed of the reciprocating motion drive mechanism. Therefore, it has stronger applicability to workpieces of different materials, pipe diameters and lengths within a certain range. In addition, the device is small in size and more convenient to use.

[0025] 3) By intermittently supplying abrasive, this invention improves the polishing effect of abrasive on the workpiece. Furthermore, the intermittent polishing method makes the workpiece polished in segments. This polishing method not only improves the polishing efficiency but also improves the polishing uniformity of small holes with large depth-to-diameter ratios. At the same time, this polishing effect can more effectively avoid abrasive clogging during the polishing process. Attached Figure Description

[0026] Figure 1 This is a top view of the structure of the present invention.

[0027] Figure 2 This is a schematic diagram of the moving part structure in this invention.

[0028] Figure 3 This is a schematic diagram of the driving part structure in this invention.

[0029] Figure 4 This is a schematic diagram of the workpiece structure in this invention.

[0030] Figure 5 This is a schematic diagram of the connection structure between the clamping assembly and the workpiece in this invention.

[0031] Figure 6 This is a schematic diagram of the connection structure between the reciprocating block and the return spring in this invention.

[0032] In the figure, 1-base support plate, 2-moving part, 3-drive part, 4-workpiece part, 5-lead screw, 6-first support seat, 7-first linear slide rail, 8-ball screw support seat, 9-first slider, 10-second support seat, 11-coupling, 12-third support seat, 13-drive block, 14-reciprocating block, 15-blocking block, 16-connector, 17-ejection spring, 18-spring support block, 19-second slider, 20-second linear slide rail, 21-drive part support seat, 22-push rod, 23-stop block, 24-material cylinder support seat, 25-material cylinder, 26-connecting flange, 27-flange support frame, 28-flange support seat, 29-first clamp, 30-second clamp, 31-clamp support seat, 32-material cylinder, 33-workpiece, 34-reciprocating block connecting shaft, 35-reset spring. Detailed Implementation

[0033] In the description of this invention, it should be understood that the terms "one end", "the other end", "outer side", "upper side", "inner side", "horizontal", "coaxial", "center", "end", "length", "outer end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0034] The invention will now be further described with reference to the accompanying drawings.

[0035] Please see Figures 1-6 A polishing device for a large aspect ratio small hole with pulsating abrasive flow includes a bottom support plate 1, a moving part 2, a driving part 3, and a workpiece part 4. The bottom support plate 1 serves as a support base for the moving part 2, the driving part 3, and the workpiece part 4. The moving part 2 is mounted on the bottom support plate 1 and can perform reciprocating motion. The driving part 3 is fixed to the bottom support plate with screws via a linear guide rail. The workpiece part 4 is fixed to the bottom support plate 1 with screws. The driving part 3 and the workpiece part 4 are connected by a push rod 22, which is placed in a material cylinder 25. The reciprocating motion of the driving part 3 pushes the abrasive to achieve a pulsating polishing effect.

[0036] like Figure 2As shown, the moving part includes a reciprocating drive mechanism and a drive block 13. The reciprocating drive mechanism drives the drive block 13 to reciprocate in the front-to-back direction. The reciprocating drive mechanism is preferably an electric ball screw module, the structure of which is a known technology. It includes a motor, a lead screw 5, a first support seat 6, a first linear slide rail 7, a ball screw support seat 8, a first slider 9, a second support seat 10, a coupling 11, and a third support seat 12. The ball screw support seat 8, the first support seat 6, the second support seat 10, and the third support seat 12 support the entire moving part 2. The ball screw support seat 8 has the first support seat 6 and the second support seat 9 on each side. The third support 12 has a first linear slide rail 7 above the ball screw support 8. The screw 5 is clamped between the first support 6 and the second support 10 and is connected to the motor through the coupling 11. The third support 12 supports the motor. The first slider 9 is fitted with the screw 5 through a threaded hole and is mounted on the first linear slide rail 7. The motor drives the screw 5 to rotate through the coupling 11, thereby driving the first slider 9 to move linearly along the first linear slide rail 7. The drive block 13 is fixed to the first slider 9 with screws and reciprocates with the first slider 9, thereby driving the reciprocating motion of the drive part 3.

[0037] like Figure 3 , Figure 6 As shown, the drive part 3 includes a reciprocating block 14 and an ejection mechanism. The ejection mechanism is used to eject the push rod forward. The ejection mechanism includes a blocking block 15, a connecting piece 16, an ejection spring 17, a spring support block 18, a second slider 19, a second linear slide rail 20, a drive part support base 21, a push rod 22, a reciprocating connecting shaft 34, and a return spring 35. The blocking block 15 and the spring support block 18 are fixedly mounted on the drive part support base 21. The connecting piece 16 is slidably mounted on the drive part support base 21. The connecting piece 16 is a key component that can connect various parts. A cuboid slot is opened in the middle to accommodate the return spring 35 and the reciprocating block 14. The connecting piece 16 has holes at the front and rear. The rear hole is used to install the ejection spring 17, which provides a forward thrust. The rear hole is used to connect the push rod 22, which exerts a squeezing effect on the abrasive. The ejector spring 17 is connected between the connector 16 and the spring support block 18 to push the connector 16 towards the front end. The reciprocating block 14 is slidably fitted onto the connector 16. The return spring 35 is connected between the reciprocating block 14 and the connector 16 to drive the reciprocating block 14 to return to its original position. When the drive block 13 pushes the reciprocating block 14 backward, the reciprocating block 14 encounters the blocking block 15, which will cause the return spring 35 in the slot to be compressed. When the drive block 13 and the reciprocating block 14 separate, the return spring returns to its original position, thereby driving the reciprocating block 14 to return to its original position for the next cycle.

[0038] Specifically, the reciprocating block 14 is threadedly connected to the reciprocating connecting shaft 34. The return spring 35 is located in the groove in the middle of the connecting member 16 and is sleeved on the reciprocating connecting shaft 34. The two ends of the return spring 35 abut against the reciprocating block 14 and the connecting member 16 at different stages. The reciprocating spring 35, the reciprocating block 14, and the reciprocating connecting shaft 34 form a key reciprocating component. The push rod 22 is threadedly connected to the connecting member 16. The ejector spring 17 is installed in the hole in front of the connecting member 16 and is sleeved on the shaft of the spring support block 18. The two ends of the ejector spring 17 abut against the connecting member 16 and the spring support block 18 respectively. The bottom of the connecting member 16 is connected to the first slider 9 by screws. The drive block 13 reciprocates through the electric ball screw module. When the drive block 13 initially contacts the reciprocating block 14, it... 4. Moving together, when the reciprocating block 14 contacts the blocking block 15, since both parts are inclined, the reciprocating block 14 will move inward, and the return spring 35 will be compressed, as will the ejector spring 17. When the compression of the reciprocating block 14 exceeds the length of the drive block 13, the drive block 13 separates from the reciprocating block 14, and the return spring 35 and the ejector spring 17 return to their original positions. The ejector spring 17 pushes the connecting piece 16, and the push rod 22 pushes the abrasive for polishing through the elastic force of the ejector spring 17. The return spring 35 returns to its original position, and then the electric ball screw module drives the drive block 13 back to the position at the front end of the reciprocating block 14 (when the drive block 13 passes the reciprocating block 14, the reciprocating block 14 will retract, so it does not affect the return of the drive block 13), thus completing one polishing cycle. Through multiple reciprocating movements, a pulsating polishing effect is achieved.

[0039] like Figures 4-5As shown, the workpiece part 4 includes a stop block 23, a material cylinder support 24, a material cylinder 25, a connecting flange 26, a flange support frame 27, a flange support seat 28, a first clamp 29, a second clamp 30, a clamp support seat 31, a material cylinder 32, and a workpiece 33. The stop block 23 is located behind the material cylinder 25 and is used to block the connecting piece 16, so that the connecting piece 16 can be limited when it moves forward, thereby limiting the stroke of the push rod 22. The feed cylinder 25 contains abrasive material, which is pushed out by the push rod 22 to process the workpiece. The feed cylinder 25 is connected to the feed cylinder support 24 at its rear end, which provides support. The front end of the feed cylinder 25 is connected to the connecting flange 26 by screws. The front end of the connecting flange 26 is connected to the first clamp 29 by screws. The connecting flange 26 is supported by the flange support 28 and the flange support frame 27. The connecting flange 26 is a hollow tubular structure that allows the abrasive material to pass through. The flange support 28 and the flange support frame 27 are connected by screws. The second clamp 30 is connected to the clamp support 31 by screws. The workpiece 33 is fixed between the first clamp 29 and the second clamp 30 by end face limiting to ensure processing effect. The abrasive material enters through the feed hole on the upper side of the feed cylinder 25. The feed cylinder 32 is connected to the second clamp 30 to collect and store the polished abrasive material.

[0040] The first clamp 29 has a first receiving cavity. The front part of the receiving cavity is used to insert the workpiece 33, and the rear part of the receiving cavity is used to insert the second clamp 30. The second clamp 30 is used to abut against the front end of the workpiece 33 and has a through hole corresponding to the position of the small hole of the workpiece 33. The through hole is connected to the material cylinder 32.

[0041] During the polishing process, the reciprocating drive mechanism moves the drive block 13 backward, which in turn moves the reciprocating block 14 along with the connecting piece 16 backward, compressing the ejector spring 17. As the reciprocating block 14 moves backward, it contacts and is squeezed by the blocking block 15, causing it to move away from the drive block 13. When the reciprocating block 14 moves to a state where it is separated from the drive block 13, the return spring 35 and the ejector spring 17 simultaneously return to their original positions. The ejector spring 17 then moves the connecting piece 16 along with the push rod 22 forward, causing the push rod 22 to spray the abrasive from the material cylinder 25 onto the fixture assembly. The abrasive polishes the small holes in the workpiece 33. The return spring 35 then moves the reciprocating block 14 outward, and the electric ball screw module moves the drive block 13 back to its original position at the front end of the reciprocating block 14, completing one polishing cycle. Multiple reciprocating movements achieve a pulsating polishing effect. The number of abrasive feeds corresponds to the push rod ejection frequency.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polishing device for a large aspect ratio small hole with pulsating abrasive flow, characterized in that, Includes the moving part (2), the driving part (3), and the workpiece part (4); The moving part (2) includes a drive block (13) and a reciprocating motion drive mechanism, which is used to drive the drive block (13) to reciprocate in the front-back direction; The drive unit (3) includes a push rod (22) and a ejection mechanism, which is used to eject the push rod (22) forward. The workpiece part (4) includes a clamping assembly and a material cylinder (25). The clamping assembly is used to clamp the workpiece (33), and the material cylinder (25) is used to store abrasive and slides with the push rod (22). It is located between the clamping assembly and the push rod (22) and corresponds to the position of the clamping assembly and the push rod (22). The polishing device is configured such that during the polishing process, the reciprocating drive mechanism drives the drive block (13) to move backward, so that the drive block (13) activates the ejection mechanism. The activated ejection mechanism drives the push rod (22) to eject forward, so that the push rod (22) sprays the abrasive in the material cylinder (25) to the fixture assembly, and polishes the small hole of the workpiece (33) through the abrasive.

2. The polishing device for a large aspect ratio small hole with pulsating abrasive flow according to claim 1, characterized in that, The reciprocating motion drive mechanism is an electric ball screw module.

3. The polishing device for a large aspect ratio small hole with pulsating abrasive flow according to claim 1, characterized in that, The ejection mechanism includes a reciprocating block (14), a blocking block (15), a connecting piece (16), an ejection spring (17), a spring support block (18), and a drive part support seat (21). The blocking block (15) and the spring support block (18) are fixedly mounted on the drive part support seat (21). The connecting piece (16) is slidably mounted on the drive part support seat (21). The push rod (22) is mounted on the connecting piece (16). The ejection spring (17) is connected between the connecting piece (16) and the spring support block (18) to push the connecting piece (16) toward the front end. The reciprocating block (14) is slidably fitted on the connecting piece (16). The reset spring (35) is connected between the reciprocating block (14) and the connecting piece (16) to drive the reciprocating block (14) to reset. The polishing device is configured such that during the polishing process, the reciprocating drive mechanism drives the drive block (13) to move backward, and the drive block (13) drives the reciprocating block (14) and the connecting piece (16) to move backward, so that the ejector spring (17) is compressed. When the reciprocating block (14) moves backward, it contacts the blocking block (15) and is squeezed by the blocking block (15), so that the reciprocating block (14) moves away from the drive block (13). When the reciprocating block (14) moves to the state of being separated from the drive block (13), the ejector spring (17) drives the connecting piece (16) and the push rod (22) to eject forward, so that the push rod (22) sprays the abrasive in the material cylinder (25) to the fixture assembly, and polishes the small hole of the workpiece (33) through the abrasive.

4. The polishing apparatus for a large aspect ratio small hole with pulsating abrasive flow according to claim 3, characterized in that, The rear side of the reciprocating block (14) is set as an inclined surface or a circular arc surface, and the front side of the blocking block (15) is set as an inclined surface or a circular arc surface. The rear side of the reciprocating block (14) is used to cooperate with the front side of the blocking block (15).

5. The polishing apparatus for a large aspect ratio small hole with pulsating abrasive flow according to claim 3, characterized in that, The drive support base (21) is provided with a second linear slide rail (20), and the bottom of the connector (16) is connected to the second linear slide rail (20) through a second slider (19).

6. The polishing apparatus for a large aspect ratio small hole with pulsating abrasive flow according to claim 1, characterized in that, The feed inlet is provided on the upper side of the feed cylinder (25).

7. The polishing apparatus for a large aspect ratio small hole with pulsating abrasive flow according to claim 1, characterized in that, The clamping assembly includes a first clamp (29) and a second clamp (30). The first clamp (29) has a first receiving cavity, the front of which is used to insert a workpiece (33), and the rear of which is used to insert a second clamp (30). The second clamp (30) is used to abut against the front end of the workpiece (33) and has a through hole corresponding to the position of the small hole of the workpiece (33).

8. The polishing apparatus for a large aspect ratio small hole with pulsating abrasive flow according to claim 7, characterized in that, The workpiece part (4) also includes a barrel (32), which is connected to a second clamp (30) for collecting polished abrasive.

9. The polishing apparatus for a large aspect ratio small hole with pulsating abrasive flow according to claim 7, characterized in that, The material cylinder (25) is connected to the first clamp (29) via a connecting flange (26), the connecting flange (26) is fitted with a connecting flange support frame (27), and the second clamp (30) is fitted with a connecting clamp support seat (31).

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