Complex burr cleaning device and method for deep-cavity thin-wall precision die casting
Through the unique clamping structure and adaptive adjustment mechanism, the damage problems of deep cavity thin-walled precision die castings during clamping and burr removal are solved, achieving efficient and safe burr cleaning and product quality improvement.
Patent Information
- Application Number
- CN202510565277.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2025-08-01
AI Technical Summary
The traditional fixing method is difficult to adapt to the complex shape of deep cavity thin-walled precision die castings, resulting in damage to the casting surface during clamping and the lack of adaptive adjustment capabilities of existing burr tools, which affects product accuracy and quality.
The unique clamping structure and adaptive adjustment mechanism are adopted to utilize the coordination between the clamping arm and the roller and the elastic recovery of the spring to ensure the stable clamping of the castings, and the adaptive adjustment of the cutting head is achieved through the compression and recovery of the spring to avoid excessive cutting of the castings.
Effectively protect the surface integrity of the castings, improve product quality, ensure efficient and safe burr removal, and realize automatic collection and cleaning of burrs.
Smart Images
Figure CN120395000A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of deburring of castings, and particularly to a complex deburring device and method for deep-cavity thin-wall precision die-castings. Background Art
[0002] With the development of the manufacturing industry, the demand for deep-cavity thin-wall precision die-castings is increasing day by day. Such die-castings have key applications in fields such as aerospace, automotive parts, and electronic equipment. However, burrs are inevitably generated during the die-casting production process. Due to the special structure of deep-cavity thin-wall precision die-castings, traditional deburring methods and devices are difficult to meet the production requirements. Traditional fixing methods usually use rigid jigs, which are difficult to adapt to the complex shapes of deep-cavity thin-wall precision die-castings. During the clamping process, it is extremely easy to cause scratches, deformation and other damages to the surface of the castings, affecting the accuracy and quality of the products. Moreover, most of the existing deburring tools lack the ability of adaptive adjustment. When encountering burrs or protrusions on the surface of the castings, they cannot automatically avoid them, and are prone to over-cutting the thin-wall parts, damaging the structural integrity of the castings, resulting in unqualified product quality, and affecting the performance and service life of the products.
[0003] Therefore, it is very necessary to propose a complex deburring device and method for deep-cavity thin-wall precision die-castings to solve the above problems. Summary of the Invention
[0004] The purpose of the present invention is to provide a complex deburring device and method for deep-cavity thin-wall precision die-castings to solve the problems that traditional fixing methods are extremely easy to cause scratches, deformation and other damages to the surface of the castings during the clamping process and the existing deburring tools lack the ability of adaptive adjustment.
[0005] To achieve the above purpose, the present invention provides the following technical solutions: A complex deburring device for deep-cavity thin-wall precision die-castings, comprising a base, a support panel, and a workbench. The support panel is arranged between the base and the workbench. The workbench is arranged above the support panel, and the base, the support panel, and the workbench are connected to each other through connecting pieces. Sliding plates are slidably installed on both the left and right sides of the top of the support panel. A driving device is installed on the support panel, and the driving device is used to drive the sliding plates to slide. A plurality of clamping members are movably installed on the workbench. Each clamping member includes two mutually perpendicular clamping arms. A roller is rotatably installed at one end of each clamping arm. The clamping members are rotatably installed on the sliding plates. A chute is arranged on the workbench to cooperate with the clamping members and the sliding plates for horizontal sliding. A plurality of first springs are installed on the workbench. One of the clamping arms in the clamping member is fixedly connected to the first spring; Above the workbench, a deburring tool holder is provided. Inside the deburring tool holder, there are two independent cavity structures, upper and lower. Inside the deburring tool holder, a plurality of second springs are fixedly connected. The second springs are arranged in an array inside the two cavities of the deburring tool holder. One end of the second spring is connected to a cutter head, and one end of the cutter head movably penetrates through one side of the deburring tool holder. Above the workbench, a driving motor is also provided, and the driving motor is used to drive the deburring tool holder to remove the burrs of the casting.
[0006] Preferably, the driving device includes a rotating arm, the rotating arm is rotatably installed at the bottom of the support panel, both ends of the rotating arm are rotatably installed with connecting arms, one end of the connecting arm is rotatably installed on the sliding plate, a slide rail strip is arranged at the bottom of the sliding plate, a slide rail for cooperating with the slide rail strip to slide is arranged at the top of the support panel, and a first motor is fixedly installed at the top of the support panel, and the first motor is drivingly connected to the sliding plate.
[0007] Preferably, a rectangular tube is fixedly installed on the base, a threaded rod is rotatably installed on the base, and one end of the threaded rod penetrates through and is installed inside the rectangular tube. A first gear is fixedly installed at the bottom of the threaded rod, a second gear is meshed and connected to one side of the first gear, the second gear is rotatably installed on the base through a rotating shaft, and a second motor is fixedly installed at the bottom of the rectangular tube, and the second motor is drivingly connected to the second gear.
[0008] Preferably, an adjusting plate is slidably installed inside the rectangular tube, and the adjusting plate is threadedly installed on the threaded rod.
[0009] Preferably, an assembly frame is arranged at the bottom of the deburring tool holder, a knob is rotatably installed at the bottom of the deburring tool holder, a strip-shaped hole adapted to the knob is arranged on the assembly frame, and the deburring tool holder and the assembly frame are fixedly connected through the knob and the strip-shaped hole.
[0010] Preferably, a sliding rod is fixedly connected to the assembly frame, a hollow sleeve is fixedly connected to the adjusting plate, one end of the hollow sleeve penetrates through the rectangular tube, the sliding rod is slidably connected to the hollow sleeve, and the driving motor is fixedly installed on the hollow sleeve.
[0011] Preferably, an empty slot for cooperating with the hollow sleeve to slide up and down is arranged on one side of the rectangular tube.
[0012] Preferably, a burr collection groove is arranged on the workbench, a collection box is movably installed at the bottom of the workbench, the top of the collection box is open, and the collection box is communicated with the burr collection groove.
[0013] Preferably, a method for cleaning complex burrs of deep cavity thin-walled precision castings includes: Preparation step: Place the casting on the workbench; Fixing step: The casting is clamped and fixed through the clamping arm and the driving device, so that the casting is always fixed in the working area of the workbench; Burr removal step: The position of the adjusting plate, the deburring tool holder and the driving motor is adjusted through the threaded rod. The deburring tool holder is driven by the driving motor to perform deburring work. After the deburring tool holder enters the deep cavity of the casting, the tool head is affected by the force from the surface of the deep cavity of the casting. When the tool head encounters burrs or surface protrusions, the resistance increases, the spring is compressed, and the tool retreats backward. When the tool passes through the flat area, the resistance decreases, and the elastic element recovers part of the deformation, and the tool holder continues to advance forward to complete the burr removal work.
[0014] The technical effects and advantages of the present invention: 1. The device adopts a unique clamping structure. The two mutually perpendicular clamping arms of the clamping part cooperate with the first spring, and can stably fix the casting under the action of the driving device. During the clamping process, the rollers rotatably installed at one end of the clamping arm reduce the frictional damage to the surface of the casting, especially suitable for thin-walled precision die-castings, and avoid secondary damage to the casting during the fixing process. Moreover, when there are certain changes in the shape of the casting, the clamping part can better adaptively adjust its position by the synergistic effect of the rollers and the first spring, ensuring that the casting is always firmly located in the working area of the workbench during the entire deburring process, laying a foundation for subsequent precise deburring.
[0015] 2. When the tool head contacts the surface of the casting, especially when entering the deep cavity, if it encounters burrs or surface protrusions, the resistance received by the tool head increases, the second spring is compressed, and the tool head retreats backward, avoiding excessive cutting or damage to the thin wall of the casting; when passing through the flat area, the resistance decreases, the second spring recovers part of the deformation, and the tool head continues to advance forward for cutting. This self-adaptive adjustment mechanism enables the tool head to efficiently and safely remove burrs, ensuring both the cleaning effect and maximizing the protection of the structural integrity of the deep cavity thin-walled precision die-casting, improving the product quality.
[0016] 3. The burr collection groove set on the workbench is interconnected with the collection box movably installed at the bottom. During the deburring process, the generated burrs will automatically fall into the burr collection groove and then fall into the collection box along the groove, facilitating the unified cleaning of burrs and keeping the working area clean. Description of the drawings
[0017] Figure 1 It is a schematic structural diagram of the complex burr cleaning device for deep cavity thin-walled precision die-castings of the present invention.
[0018] Figure 2 It is a schematic structural diagram of the clamping arm and roller installation of the present invention.
[0019] Figure 3 It is a schematic structural diagram of the bottom driving structure of the support panel of the present invention.
[0020] Figure 4 This is a schematic diagram of the top drive structure of the support panel of the present invention.
[0021] Figure 5 This is a schematic diagram of the installation structure of the cutter head and the drive motor of the present invention.
[0022] Figure 6 This is a schematic diagram of the internal structure of the hair removal knife holder of the present invention.
[0023] Figure 7 This is a schematic diagram of the installation structure of the adjusting plate and the threaded rod of the present invention.
[0024] Figure 8 This is a schematic diagram of the installation structure of the hair removal knife holder and the assembly rack of the present invention.
[0025] Figure 9 This is a schematic diagram of the installation position structure of the collection box of the present invention.
[0026] In the figure: 1, base; 2, support panel; 21, slide plate; 211, slide rail strip; 22, slide rail; 23, motor 1; 3, workbench; 31, clamping member; 311, clamping arm; 312, roller; 32, chute; 33, spring 1; 4, drive device; 41, rotating arm; 42, connecting arm; 5, hair removal knife holder; 51, spring 2; 52, cutter head; 6, drive motor; 7, rectangular tube; 71, threaded rod; 711, gear 1; 72, adjusting plate; 8, gear 2; 9, motor 2; 10, assembly rack; 11, knob; 12, strip hole; 13, slide rod; 14, hollow sleeve; 15, burr collection groove; 16, collection box. Detailed implementation manners
[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0028] The present invention provides as Figures 1-9The shown complex burr cleaning device for deep cavity thin-walled precision die-castings includes a base 1, a support panel 2, and a workbench 3. The support panel 2 is arranged between the base 1 and the workbench 3. The workbench 3 is arranged above the support panel 2, and the base 1, the support panel 2, and the workbench 3 are interconnected through connecting pieces. Sliding plates 21 are slidably installed on both the left and right sides of the top of the support panel 2. A driving device 4 is installed on the support panel 2, and the driving device 4 is used to drive the sliding of the sliding plates 21. A plurality of clamping members 31 are movably installed on the workbench 3. The clamping members 31 include two mutually perpendicular clamping arms 311. A roller 312 is rotatably installed at one end of the clamping arm 311. The clamping members 31 are rotatably installed on the sliding plates 21. A chute 32 for coordinating the horizontal sliding of the clamping members 31 and the sliding plates 21 is arranged on the workbench 3. A plurality of first springs 33 are installed on the workbench 3. One of the clamping arms 311 in the clamping member 31 is fixedly connected to the first spring 33; Above the workbench 3, a deburring tool holder 5 is arranged. There are two independent cavity structures, upper and lower, inside the deburring tool holder 5. A plurality of second springs 51 are fixedly connected inside the deburring tool holder 5. The second springs 51 are arranged in an array inside the two cavities of the deburring tool holder 5. One end of the second spring 51 is connected to a tool bit 52. One end of the tool bit 52 movably penetrates through one side of the deburring tool holder 5. A driving motor 6 is also arranged above the workbench 3, and the driving motor 6 is used to drive the deburring tool holder 5 to remove the burrs on the casting.
[0029] Further, the driving device 4 includes a rotating arm 41. The rotating arm 41 is rotatably installed at the bottom of the support panel 2. Connecting arms 42 are rotatably installed at both ends of the rotating arm 41. One end of the connecting arm 42 is rotatably installed on the sliding plate 21. A slide rail strip 211 is arranged at the bottom of the sliding plate 21. A slide rail 22 for coordinating the sliding of the slide rail strip 211 is arranged at the top of the support panel 2. A first motor 23 is fixedly installed at the top of the support panel 2, and the first motor 23 is drivingly connected to the sliding plate 21.
[0030] Further, a rectangular tube 7 is fixedly installed on the base 1. A threaded rod 71 is rotatably installed on the base 1, and one end of the threaded rod 71 penetrates through and is installed inside the rectangular tube 7. A first gear 711 is fixedly installed at the bottom of the threaded rod 71. A second gear 8 is meshed and connected to one side of the first gear 711. The second gear 8 is rotatably installed on the base 1 through a rotating shaft. A second motor 9 is fixedly installed at the bottom of the rectangular tube 7, and the second motor 9 is drivingly connected to the second gear 8.
[0031] Further, an adjusting plate 72 is slidably installed inside the rectangular tube 7, and the adjusting plate 72 is threadedly installed on the threaded rod 71.
[0032] Further, an assembly frame 10 is arranged at the bottom of the deburring tool holder 5. A knob 11 is rotatably installed at the bottom of the deburring tool holder 5. A strip-shaped hole 12 adapted to the knob 11 is arranged on the assembly frame 10. The deburring tool holder 5 and the assembly frame 10 are fixedly connected through the knob 11 and the strip-shaped hole 12.
[0033] Further, a slide rod 13 is fixedly connected to the assembly frame 10, a hollow sleeve 14 is fixedly connected to the adjusting plate 72, one end of the hollow sleeve 14 penetrates through the rectangular pipe 7, the slide rod 13 is slidably connected to the hollow sleeve 14, and the driving motor 6 is fixedly installed on the hollow sleeve 14.
[0034] Further, an empty groove for cooperating with the up-and-down sliding of the hollow sleeve 14 is provided on one side of the rectangular pipe 7.
[0035] Further, a burr collection groove 15 is provided on the workbench 3, a collection box 16 is movably installed at the bottom of the workbench 3, the top of the collection box 16 is open, and the collection box 16 is communicated with the burr collection groove 15.
[0036] In an embodiment of the present invention, in the preparation stage, the deep cavity thin-walled precision die-casting part to be deburred is placed on the workbench 3. At this time, all components are in the initial state, the clamping member 31 does not clamp the casting, the deburring tool holder 5 is located at a suitable starting position, the driving motor 6 is not started, the first motor 23 is started, and the first motor 23 drives the rotating arm 41 to rotate around its installation point at the bottom of the support panel 2. The connecting arms 42 at both ends of the rotating arm 41 move accordingly. Since one end of the connecting arm 42 is rotatably installed on the slide plate 21, the slide rail strip 211 at the bottom of the slide plate 21 cooperates with the slide rail 22 at the top of the support panel 2, so that the slide plate 21 slides left and right on the top of the support panel 2. When the slide plate 21 slides, it drives the clamping member 31 installed thereon to move horizontally along the chute 32 on the workbench 3. The two mutually perpendicular clamping arms 311 of the clamping member 31 gradually approach the casting during the movement. When the rollers 312 on the clamping arms 311 contact the casting, they move along the surface of the casting, so that the two mutually perpendicular clamping arms 311 fix the casting on the workbench 3. After the deburring of the casting is completed, the elastic force generated by the first spring 33 causes the clamping arms 311 to return to the initial position for the next use. The rollers 312 rotatably installed at one end of the clamping arms 311 can reduce the frictional damage to the surface of the casting during the clamping process, and at the same time, it is convenient for the clamping member 31 to better adaptively adjust the position when the casting has a certain shape change, and finally realize the stable clamping and fixing of the casting, ensuring that the casting is always located within the working area of the workbench 3 during the entire deburring process; Next, start the second motor 9. The second motor 9 drives the second gear 8 to rotate. Since the second gear 8 meshes with the first gear 711 which is fixed at the bottom of the threaded rod 71, the first gear 711 rotates accordingly, thereby driving the threaded rod 71 to rotate on the base 1. The adjusting plate 72 is threadedly installed on the threaded rod 71 and rotates inside the rectangular tube 7. As the threaded rod 71 rotates, the adjusting plate 72 moves up and down along the axial direction of the threaded rod 71 inside the rectangular tube 7. The hollow sleeve 14 fixedly connected to the adjusting plate 72 moves synchronously with the adjusting plate 72. The hollow sleeve 14 is slidably connected to the slide rod 13 on the assembly frame 10. The deburring tool holder 5 is fixedly connected to the assembly frame 10 through the knob 11 and the strip hole 12, and the driving motor 6 is installed on the hollow sleeve 14. Therefore, the deburring tool holder 5 and the driving motor 6 move up and down with the movement of the adjusting plate 72 to adjust the position of the deburring tool holder 5 so that it can accurately align with the part of the casting where burrs need to be removed; When the deburring tool holder 5 is adjusted to the appropriate position, start the driving motor 6. The driving motor 6 drives the deburring tool holder 5 to operate. The cutting heads 52 connected to one ends of the second springs 51 arranged in an array inside the deburring tool holder 5 start to work. When the cutting heads 52 contact the surface of the casting and enter the deep cavity of the casting, if they encounter burrs or surface protrusions, the resistance received by the cutting heads 52 increases. At this time, the second springs 51 are compressed, and the cutting heads 52 retreat backward to avoid over-cutting or damaging the thin wall of the casting.
[0037] When the cutting heads 52 pass through the flat area, the resistance decreases, and the second springs 51 recover part of their deformation. The cutting heads 52 continue to advance forward with the tool holder, continuously cutting the surface of the casting to remove the burrs. In this process, the cutting heads 52 continuously make adaptive adjustments depending on the situation of the casting surface relying on the elasticity of the second springs 51 to ensure efficient and safe removal of burrs; During the process of removing burrs, the generated burrs will fall into the burr collection groove 15 on the workbench 3. The top opening of the collection box 16 movably installed at the bottom of the workbench 3 is in communication with the burr collection groove 15. The burrs fall into the collection box 16 along the collection groove 15, which is convenient for subsequent unified cleaning, keeps the working area clean, and avoids the accumulation of burrs from affecting the continuation of the cleaning work or damaging the equipment.
[0038] The present invention provides a method for cleaning complex burrs of deep cavity thin-walled precision castings, which is characterized by including: Preparation step: Place the casting on the workbench; Fixing step: Clamp and fix the casting through the clamping arm and the driving device so that the casting is always fixed in the working area of the workbench; Burr removal steps: Adjust the positions of the adjusting plate, deburring tool holder, and driving motor through the threaded rod. Drive the deburring tool holder through the driving motor to perform burr removal work. After the deburring tool holder enters the deep cavity of the casting, the tool head is subjected to the acting force from the surface of the deep cavity of the casting. When the tool head encounters burrs or surface protrusions, the resistance increases, the spring is compressed, and the tool retracts backward. When the tool passes through the flat area, the resistance decreases, the elastic element recovers part of the deformation, and the tool holder continues to advance forward to complete the burr removal work.
[0039] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection required by the present invention is defined by the appended claims and their equivalents.
Claims
1. A complex burr cleaning device for deep cavity thin-walled precision die castings, characterized in that: It includes a base (1), a support panel (2), and a workbench (3). The support panel (2) is arranged between the base (1) and the workbench (3), and the workbench (3) is arranged above the support panel (2). Moreover, the base (1), the support panel (2), and the workbench (3) are connected to each other through connecting pieces. Slide plates (21) are slidably installed on both the left and right sides of the top of the support panel (2). A driving device (4) is installed on the support panel (2), and the driving device (4) is used to drive the slide plates (21) to slide. A plurality of clamping members (31) are movably installed on the workbench (3). The clamping member (31) includes two mutually perpendicular clamping arms (311). A roller (312) is rotatably installed at one end of the clamping arm (311). The clamping member (31) is rotatably installed on the slide plate (21). A chute (32) for coordinating the horizontal sliding of the clamping member (31) and the slide plate (21) is arranged on the workbench (3). A plurality of first springs (33) are installed on the workbench (3). One of the clamping arms (311) in the clamping member (31) is fixedly connected to the first spring (33). A hair removal tool holder (5) is arranged above the workbench (3). The interior of the hair removal tool holder (5) has two independent cavity structures up and down. A plurality of second springs (51) are fixedly connected inside the hair removal tool holder (5). The second springs (51) are arranged in an array inside the two cavities of the hair removal tool holder (5). One end of the second spring (51) is connected to a cutter head (52). One end of the cutter head (52) movably penetrates through one side of the hair removal tool holder (5). A driving motor (6) is also arranged above the workbench (3), and the driving motor (6) is used to drive the hair removal tool holder (5) to remove the burrs of the casting.
2. The complex burr cleaning device for deep cavity thin-walled precision die castings according to claim 1, wherein: The driving device (4) includes a rotating arm (41). The rotating arm (41) is rotatably installed at the bottom of the support panel (2). Connecting arms (42) are rotatably installed at both ends of the rotating arm (41). One end of the connecting arm (42) is rotatably installed on the slide plate (21). A slide rail strip (211) is arranged at the bottom of the slide plate (21). A slide rail (22) for coordinating the sliding of the slide rail strip (211) is arranged at the top of the support panel (2). A first motor (23) is fixedly installed at the top of the support panel (2), and the first motor (23) is drivingly connected to the slide plate (21).
3. The complex burr cleaning device for deep cavity thin-walled precision die castings according to claim 1, wherein: A rectangular tube (7) is fixedly installed on the base (1). A threaded rod (71) is rotatably installed on the base (1), and one end of the threaded rod (71) penetrates through and is installed inside the rectangular tube (7). A first gear (711) is fixedly installed at the bottom of the threaded rod (71). A second gear (8) is meshed and connected to one side of the first gear (711). The second gear (8) is rotatably installed on the base (1) through a rotating shaft. A second motor (9) is fixedly installed at the bottom of the rectangular tube (7), and the second motor (9) is drivingly connected to the second gear (8).
4. The complex burr cleaning device for deep cavity thin-walled precision die castings according to claim 3, wherein: A regulating plate (72) is slidably installed inside the rectangular pipe (7), and the regulating plate (72) is threadedly installed on a threaded rod (71).
5. The complex burr cleaning device for deep cavity thin-walled precision die castings according to claim 1, wherein: An assembling frame (10) is provided at the bottom of the hair removal knife holder (5). A knob (11) is rotatably installed at the bottom of the hair removal knife holder (5). A strip-shaped hole (12) adapted to the knob (11) is provided on the assembling frame (10). The hair removal knife holder (5) and the assembling frame (10) are fixedly connected through the knob (11) and the strip-shaped hole (12).
6. The complex burr cleaning device for deep cavity thin-walled precision die-castings according to any one of claims 1, 4 or 5, characterized in that: A sliding rod (13) is fixedly connected to the assembling frame (10). A hollow sleeve (14) is fixedly connected to the regulating plate (72). One end of the hollow sleeve (14) penetrates through the rectangular pipe (7). The sliding rod (13) is slidably connected to the hollow sleeve (14). A driving motor (6) is fixedly installed on the hollow sleeve (14).
7. The complex burr cleaning device for deep cavity thin-wall precision die castings according to claim 4, wherein: An empty groove for cooperating with the up-and-down sliding of the hollow sleeve (14) is provided on one side of the rectangular pipe (7).
8. The complex burr cleaning device for deep cavity thin-walled precision die castings according to claim 1, wherein: A burr collection groove (15) is provided on the workbench (3). A collection box (16) is movably installed at the bottom of the workbench (3). The top of the collection box (16) is open, and the collection box (16) communicates with the burr collection groove (15).
9. A method for cleaning complex burrs of deep cavity thin-wall precision die-castings, characterized in that, Including: Preparation step: Place the casting on the workbench; Fixing step: Clamp and fix the casting through the clamping arm and the driving device, so that the casting is always fixed in the working area of the workbench; Burr removal step: Adjust the positions of the regulating plate, the hair removal knife holder and the driving motor through the threaded rod. Drive the hair removal knife holder to perform burr removal work through the driving motor. After the hair removal knife holder enters the deep cavity of the casting, the tool head is subjected to the acting force from the surface of the deep cavity of the casting. When the tool head encounters burrs or surface protrusions, the resistance increases, the spring is compressed, and the tool retreats backward. When the tool passes through the flat area, the resistance decreases, the elastic element recovers part of the deformation, and the knife holder continues to move forward to complete the burr removal work.