Cutting device for plastic detection sheet sample

Abstract

The invention relates to the technical field of auxiliary detection cutting equipment, and particularly discloses a cutting device for a plastic detection sheet sample, the cutting device comprises a bottom plate and a plastic pipe, the plastic pipe is located above the bottom plate; the rotating type transferring assembly comprises two linear guide rails, the linear guide rails are installed at the top end of the bottom plate, the two linear guide rails are connected with a supporting frame through linear bearings, an installation base is fixedly installed at the top end of the supporting frame, a three-jaw chuck is fixedly installed between two vertical sections of the installation base, and the three-jaw chuck is connected with the supporting frame through linear bearings. The three-jaw chuck is used for fixing and rotating the plastic pipe; and the vertical plate is mounted at the top end of the bottom plate. The device is provided with an automatic cutting device for the inner and outer oxidized surfaces of the plastic detection sheets, the accuracy of subsequent detection data is improved, the device has an automatic adjusting type cutting function for the plastic detection sheets with different pipe diameters, and the stability of the cutting process of the plastic detection sheets with low hardness is improved.

Description

Technical Field

[0001] The invention relates to the technical field of auxiliary detection cutting equipment, and in particular to a cutting device for plastic detection sheet samples. Background Art

[0002] The thermal stability of plastics refers to the ability of plastics to withstand thermal shock without being destroyed. In chemistry, it refers to the difficulty of chemical reactions under certain conditions. The thermal stability of plastics represents the ability to effectively prevent, reduce or even stop the degradation of materials. The higher the energy required to destroy plastics, the more stable they are. Differential scanning calorimetry (DSC) is currently the most widely used method for testing the thermal stability of plastics. It usually measures the time or temperature required for the antioxidant stabilization system in the sample to inhibit its oxidation when the temperature is kept constant at a specified temperature or increased at a constant rate in an oxygen or air atmosphere. The oxidation induction time or oxidation induction temperature is a means of evaluating the stability level (or degree) of the material being tested. The higher the test temperature, the shorter the oxidation induction time; the faster the heating rate, the higher the oxidation induction temperature. The oxidation induction time and oxidation induction temperature are directly related to the surface area of ​​the sample that is subject to oxidation.

[0003] The DSC test standard stipulates that the sample thickness is (650±100) μm, and requires uniform thickness, parallel and flat surfaces, and no burrs. The specific surface area, sample unevenness, and residual stress of the sample will have a significant impact on the test results. In actual testing, the final form of the sample is generally a pipe. The outer surface and inner surface of the plastic pipe have been oxidized due to exposure to the air, and the surface of the pipe is curved, which invisibly increases the surface area.

[0004] Before testing, existing plastic pipes are usually cut manually or by large-scale machinery to obtain the final sample. However, manual cutting accuracy is difficult to meet the testing requirements, and large-scale mechanical processing is time-consuming, labor-intensive, and costly, resulting in insufficient efficiency in cutting the oxidized surface of the plastic pipe. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a cutting device for plastic testing thin sheet samples, which can solve the problems raised in the above background technology.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A cutting device for plastic testing thin-sheet samples, comprising: A bottom plate and a plastic pipe, wherein the plastic pipe is located above the bottom plate; Rotary transfer assembly, the rotary transfer assembly includes two linear guide rails, the linear guide rails are installed at the top end of the bottom plate, the two linear guide rails are connected with a support frame through linear bearings, a mounting seat is fixedly installed at the top end of the support frame, and a three-jaw chuck is fixedly installed between the two vertical sections of the mounting seat. The three-jaw chuck is used to fix and rotate the plastic pipe; Vertical plate, the vertical plate is installed at the top end of the bottom plate, and a limiting groove is provided on the side wall of the vertical plate. The limiting groove is arranged in a "convex" shape; First cutting assembly, the first cutting assembly is used to cut the outer wall of the plastic pipe. The first cutting assembly includes a sliding block. The sliding block is slidably installed between the two vertical sections with a narrow pitch of the limiting groove. A first L-shaped rod is fixedly installed on the side wall of the sliding block. A first scraping strip is fixedly installed at the bottom end of the vertical section of the first L-shaped rod. A first cutting knife is arranged at the bottom end of the first scraping strip. A driving mechanism for driving the sliding block to lift and lower is arranged on the side wall of the vertical plate; Second cutting assembly, the second cutting assembly is used to cut the inner wall of the plastic pipe. The second cutting assembly includes a square pipe. The square pipe penetrates and is fixedly installed between the two vertical sections with a wide pitch of the limiting groove. Two limiting columns are fixedly installed between the top wall and the bottom wall of the square pipe. Two lifting plates are slidably installed between the two limiting columns. A second L-shaped rod is fixedly installed on one side of each of the two lifting plates close to the mounting seat. A second scraping strip is fixedly installed at one end of the second L-shaped rod close to the mounting seat. Second cutting knives are arranged on the sides of the two second scraping strips away from each other; Screw rod, the screw rod penetrates and is rotatably installed at the top end and the bottom end of the square pipe. Two sections of threads with opposite helix directions and the same pitch are arranged on the side wall of the screw rod. The two lifting plates respectively match the adjacent threads. A driving assembly for driving the screw rod to rotate is arranged at the bottom end of the square pipe.

[0007] Preferably, a plurality of support feet are arranged at the bottom end of the bottom plate. The front view of the support feet is arranged in an inverted T shape. A rubber pad is arranged at the bottom end of the support feet.

[0008] Preferably, the two linear guide rails are electrically connected through a controller, and the two linear guide rails are respectively arranged parallel to the plastic pipe.

[0009] Preferably, the three-jaw chuck is composed of a chuck body, three movable jaws and a driving mechanism. The three-jaw chuck realizes the clamping and positioning of the workpiece through the radial movement of the jaws.

[0010] Preferably, the sliding block is arranged in a "soil" shape, and the sliding block is slidably connected with the vertical plate through the limiting groove.

[0011] Preferably, two first limit strips are provided at the bottom end of the first scraper strip, the end faces of the two first limit strips are fan-shaped, the two first limit strips are symmetrically arranged about the first scraper, and the distance from the first limit strip to the outer wall of the plastic tube is smaller than the distance from the blade of the first scraper to the outer wall of the plastic tube.

[0012] Preferably, the driving mechanism comprises a pneumatic cylinder, which is mounted on a side wall of the vertical plate, and the bottom end of a piston rod of the pneumatic cylinder is fixedly connected to the top end of the sliding block.

[0013] Preferably, the two second scraper strips are symmetrically arranged about the central axis of the plastic tube, and the distance from the top of the second scraper strip located at the upper side to the central axis of the plastic tube is smaller than the inner diameter of the plastic tube.

[0014] Preferably, a second limit strip is provided on the side away from each other of the two second scraper strips, the two second limit strips are symmetrically arranged about the adjacent second scraper, the end face of the second limit strip is fan-shaped, and the distance from the second limit strip to the inner wall of the plastic tube is smaller than the distance from the blade of the second scraper to the inner wall of the plastic tube.

[0015] Preferably, the drive assembly includes a U-shaped block, which is fixedly mounted on an outer wall of one side of the vertical plate, a reduction gearbox is fixedly mounted on the top of the U-shaped block, the output shaft of the reduction gearbox is fixedly connected to a screw via a coupling, a servo motor is fixedly mounted on the bottom end of the U-shaped block, and the output shaft of the servo motor is fixedly connected to the input shaft of the reduction gearbox via a coupling.

[0016] The beneficial effects of the present invention are: 1. By setting a rotary transfer assembly, the beneficial effect that can be obtained is that the plastic pipe is located above the bottom plate, the linear guide rail is installed on the top of the bottom plate, the two linear guide rails are connected to a support frame through a linear bearing, a mounting seat is fixedly installed on the top of the support frame, a three-jaw chuck is fixedly installed between two vertical sections of the mounting seat, the three-jaw chuck is used to fix and rotate the plastic pipe, the first cutting assembly is used to cut the outer wall of the plastic pipe, the first cutting assembly includes a sliding block, the sliding block is slidably installed between two vertical sections with a narrow spacing in the limiting groove, the side wall of the sliding block is fixedly installed with a first L-shaped rod, and the bottom end of the vertical section of the first L-shaped rod is fixedly installed with A first scraper strip, a first scraper is arranged at the bottom end of the first scraper strip, a driving mechanism for driving the sliding block to rise and fall is arranged on the side wall of the vertical plate, a second cutting assembly is used to cut the inner wall of the plastic tube, the second cutting assembly comprises a square tube, the square tube passes through and is fixedly installed between two vertical sections with a width spacing of the limiting groove, two limiting columns are fixedly installed between the top wall and the bottom wall of the square tube, two lifting plates are slidably installed between the two limiting columns, a second L-shaped rod is fixedly installed on one side of the two lifting plates close to the mounting seat, a second scraper strip is fixedly installed on one end of the second L-shaped rod close to the mounting seat, and a second scraper is arranged on the side away from the two second scrapers; The three-jaw chuck clamps and positions the plastic tube through the radial movement of the jaws. Two linear guides drive the support frame, the mounting seat, the three-jaw chuck and the plastic tube to move synchronously toward the vertical plate. At the same time, the three-jaw chuck drives the plastic tube to rotate. The first scraper cuts the outer wall of the plastic tube, and the second scraper cuts the inner wall of the plastic tube to complete the cutting of the inner and outer surfaces of the plastic tube. It has an automatic cutting device for the inner and outer oxidized surfaces of the plastic inspection sheet, which improves the accuracy of subsequent inspection data.

[0017] 2. By setting the driving mechanism and the driving assembly, the beneficial effect that can be obtained is that the screw penetrates and is rotatably installed on the top and bottom ends of the square tube, the side wall of the screw is provided with two sections of threads with opposite rotation directions and the same pitch, the two lifting plates are matched with adjacent threads respectively, the pneumatic cylinder is installed on the side wall of the vertical plate, the bottom end of the piston rod of the pneumatic cylinder is fixedly connected to the top end of the sliding block, the driving assembly includes a U-shaped block, the U-shaped block is fixedly installed on the outer wall of one side of the vertical plate, a reduction box is fixedly installed on the top of the U-shaped block, the output shaft of the reduction box is fixedly connected to the screw through a coupling, a servo motor is fixedly installed on the bottom end of the U-shaped block, and the output shaft of the servo motor is fixedly connected to the input shaft of the reduction box through a coupling; According to the diameter of the plastic pipe, the pneumatic cylinder drives the sliding block to slide in the limit groove of the vertical plate, and the first L-shaped rod, the first scraper, and the first scraper rise and fall synchronously, and the first scraper matches the outer wall of the plastic pipe. At the same time, the servo motor cooperates with the reduction gearbox to drive the screw to rotate, and the two lifting plates move away from each other along the two limit columns. The second L-shaped rod, the second scraper, and the second scraper rise and fall synchronously with the adjacent lifting plates, and the second scraper matches the inner wall of the plastic pipe, which has the function of automatically adjusting the cutting of plastic inspection sheets with different diameters.

[0018] 3. By setting the first limit strip and the second limit strip, the beneficial effect that can be obtained is that two first limit strips are set at the bottom end of the first scraper strip, the end faces of the two first limit strips are set in a fan shape, the two first limit strips are symmetrically set about the first scraper, the distance from the first limit strip to the outer wall of the plastic tube is smaller than the distance from the blade of the first scraper to the outer wall of the plastic tube, the two second scrapers are symmetrically set about the central axis of the plastic tube, and the distance from the top end of the second scraper strip located at the top to the central axis of the plastic tube is smaller than the inner diameter of the plastic tube; When the material of the plastic tube is relatively hard, the first scraper cuts the outer wall of the plastic tube, and the second scraper cuts the inner wall of the plastic tube, thereby completing the cutting of the inner and outer surfaces of the plastic tube; when the material hardness of the plastic tube is relatively low, the first limit strip assists in supporting and limiting the outer wall of the plastic tube, thereby ensuring the stability of the first scraper in cutting the outer wall of the plastic tube, and the second limit strip assists in supporting and limiting the inner wall of the plastic tube, thereby ensuring the stability of the second scraper in cutting the inner wall of the plastic tube; at the same time, the two second scrapers synchronously support and cut the plastic tube, thereby improving the stability of the cutting process of the plastic inspection sheet with lower hardness. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a diagram of the installation structure of the square tube in the present invention; Figure 3 This is a structural diagram of the installation of the vertical plate in the present invention; Figure 4 This is a structural diagram of the installation of the sliding block in the present invention; Figure 5 This is a structural diagram of the screw in the present invention; Figure 6 For the present invention Figure 2 A in the enlarged view; Figure 7 For the present invention Figure 2 The enlarged view of point B in the figure; Figure 8 It is the installation structure diagram of the driving assembly in the present invention; Fig. 9 It is an exploded view of the driving assembly in the present invention.

[0021] Description of reference numerals: In the figure: 1. base plate; 11. supporting foot; 2. plastic tube; 31. linear guide; 32. supporting frame; 33. mounting seat; 34. three-jaw chuck; 4. vertical plate; 41. limiting groove; 51. sliding block; 52. first L-shaped rod; 53. first scraper; 54. first scraper; 55. first limiting strip; 56. pneumatic cylinder; 6. square tube; 61. limiting column; 62. lifting plate; 63. second L-shaped rod; 64. second scraper; 65. second scraper; 66. second limiting strip; 7. screw; 71. U-shaped block; 72. reduction box; 73. servo motor. DETAILED DESCRIPTION

[0022] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are clearly and completely described below in combination with the accompanying drawings and preferred embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present application, it should be understood that the orientation or position relationship indicated by "inside", "outside", etc. is based on the orientation or position described in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, a specific orientation structure and operation, and therefore cannot be understood as a limitation on the present application.

[0024] Reference Figure 1-Figure 9 , a cutting device for plastic testing thin-sheet samples disclosed in the present invention, comprising a bottom plate 1 and a plastic tube 2, the plastic tube 2 being located above the bottom plate 1, a plurality of supporting legs 11 being arranged at the bottom end of the bottom plate 1, the front view of the supporting legs 11 being arranged in an inverted T-shape, and a rubber pad being arranged at the bottom end of the supporting legs 11; Rotary transfer assembly, the rotary transfer assembly includes two linear guides 31, the linear guides 31 are installed on the top of the base plate 1, the two linear guides 31 are electrically connected through a controller, the two linear guides 31 are respectively arranged in parallel with the plastic pipe 2, the two linear guides 31 are connected to a support frame 32 through a linear bearing, a mounting seat 33 is fixedly installed on the top of the support frame 32, a three-jaw chuck 34 is fixedly installed between two vertical sections of the mounting seat 33, the three-jaw chuck 34 is used to fix and rotate the plastic pipe 2, the three-jaw chuck 34 is composed of a chuck body, three movable jaws and a driving mechanism, and the three-jaw chuck 34 realizes the clamping and positioning of the workpiece through the radial movement of the jaws; The vertical plate 4 is installed on the top of the bottom plate 1. The side wall of the vertical plate 4 is provided with a limiting groove 41, and the limiting groove 41 is arranged in a "convex" shape; The first cutting assembly is used to cut the outer wall of the plastic pipe 2. The first cutting assembly includes a sliding block 51. The sliding block 51 is slidably installed between two vertical sections with a narrow spacing in the limiting groove 41. The sliding block 51 is arranged in a "earth" shape. The sliding block 51 is slidably connected to the vertical plate 4 through the limiting groove 41. A first L-shaped rod 52 is fixedly installed on the side wall of the sliding block 51. A first scraper 53 is fixedly installed at the bottom end of the vertical section of the first L-shaped rod 52. A first scraper 54 is arranged at the bottom end of the first scraper 53. The first scraper 54 Two first limit bars 55 are arranged at the bottom end, and the end faces of the two first limit bars 55 are arranged in a fan shape. The two first limit bars 55 are arranged symmetrically about the first scraper 54. The distance between the first limit bar 55 and the outer wall of the plastic tube 2 is smaller than the distance between the blade of the first scraper 54 and the outer wall of the plastic tube 2. The side wall of the vertical plate 4 is provided with a driving mechanism for driving the sliding block 51 to rise and fall. The driving mechanism includes a pneumatic cylinder 56, which is installed on the side wall of the vertical plate 4. The bottom end of the piston rod of the pneumatic cylinder 56 is fixedly connected to the top end of the sliding block 51; The second cutting assembly is used to cut the inner wall of the plastic pipe 2. The second cutting assembly includes a square tube 6. The square tube 6 passes through and is fixedly installed between two vertical sections with a wide spacing of the limiting groove 41. Two limiting columns 61 are fixedly installed between the top wall and the bottom wall of the square tube 6. Two lifting plates 62 are slidably installed between the two limiting columns 61. A second L-shaped rod 63 is fixedly installed on one side of the two lifting plates 62 close to the mounting seat 33. A second scraper 64 is fixedly installed on one end of the second L-shaped rod 63 close to the mounting seat 33. The two second scrapers 64 are about The central axis of the plastic tube 2 is symmetrically arranged, the distance from the top of the second scraper strip 64 located at the top to the central axis of the plastic tube 2 is less than the inner diameter of the plastic tube 2, the second scraper blade 65 is arranged on the side away from the two second scraper strips 64, the second limiting strip 66 is arranged on the side away from the two second scraper strips 64, the two second limiting strips 66 are symmetrically arranged about the adjacent second scraper blades 65, the end faces of the second limiting strips 66 are arranged in a fan shape, and the distance from the second limiting strip 66 to the inner wall of the plastic tube 2 is less than the distance from the blade of the second scraper blade 65 to the inner wall of the plastic tube 2; The screw 7 passes through and is rotatably installed on the top and bottom ends of the square tube 6. The side wall of the screw 7 is provided with two sections of threads with opposite rotation directions and the same pitch. The two lifting plates 62 are respectively matched with adjacent threads. The bottom end of the square tube 6 is provided with a driving assembly for driving the rotation of the screw 7. The driving assembly includes a U-shaped block 71. The U-shaped block 71 is fixedly installed on the outer wall of one side of the vertical plate 4. A reduction box 72 is fixedly installed on the top of the U-shaped block 71. The output shaft of the reduction box 72 is fixedly connected to the screw 7 through a coupling. A servo motor 73 is fixedly installed on the bottom end of the U-shaped block 71. The output shaft of the servo motor 73 is fixedly connected to the input shaft of the reduction box 72 through a coupling.

[0025] The working principle and use process of the present invention are as follows: first, the three-jaw chuck 34 clamps and positions the plastic tube 2 through radial movement of the jaws. Then, according to the diameter of the plastic tube 2, the pneumatic cylinder 56 drives the sliding block 51 to slide in the limiting groove 41 of the vertical plate 4. The first L-shaped rod 52, the first scraper 53, and the first scraper 54 rise and fall synchronously. The first scraper 54 matches the outer wall of the plastic tube 2. At the same time, the servo motor 73 cooperates with the reduction box 72 to drive the screw 7 to rotate. The two lifting plates 62 move away from each other along the two limiting columns 61. The second L-shaped rod 63, the second scraper 64, and the second scraper 65 rise and fall synchronously with the adjacent lifting plates 62. The second scraper 65 matches the inner wall of the plastic tube 2. Then, the two linear guides 31 drive the support frame 32, The mounting seat 33, the three-jaw chuck 34 and the plastic tube 2 move synchronously toward the vertical plate 4. At the same time, the three-jaw chuck 34 drives the plastic tube 2 to rotate. When the material of the plastic tube 2 is harder, the first scraper 54 cuts the outer wall of the plastic tube 2, and the second scraper 65 cuts the inner wall of the plastic tube 2 to complete the cutting of the inner and outer surfaces of the plastic tube 2; when the hardness of the material of the plastic tube 2 is lower, the first limit strip 55 assists in supporting and limiting the outer wall of the plastic tube 2 to ensure the stability of the first scraper 54 in cutting the outer wall of the plastic tube 2, and the second limit strip 66 assists in supporting and limiting the inner wall of the plastic tube 2 to ensure the stability of the second scraper 65 in cutting the inner wall of the plastic tube 2. At the same time, the two second scrapers 65 support and cut the plastic tube 2 synchronously.

[0026] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A cutting device for plastic testing thin sheet samples, characterized in that: Including: A bottom plate (1) and a plastic pipe (2), and the plastic pipe (2) is located above the bottom plate (1); A rotary transfer assembly, the rotary transfer assembly includes two linear guide rails (31), the linear guide rails (31) are installed at the top end of the bottom plate (1), the two linear guide rails (31) are connected with a support frame (32) through linear bearings, a mounting seat (33) is fixedly installed at the top end of the support frame (32), and a three-jaw chuck (34) is fixedly installed between the two vertical sections of the mounting seat (33), and the three-jaw chuck (34) is used to fix and rotate the plastic pipe (2); A vertical plate (4), and the vertical plate (4) is installed at the top end of the bottom plate (1); A first cutting assembly, the first cutting assembly is used to cut the outer wall of the plastic pipe (2), the first cutting assembly includes a sliding block (51), the sliding block (51) is slidably installed between the two vertical sections of the narrow pitch of the limiting groove (41), a first L-shaped rod (52) is fixedly installed on the side wall of the sliding block (51), a first scraping strip (53) is fixedly installed at the bottom end of the vertical section of the first L-shaped rod (52), a first cutting knife (54) is arranged at the bottom end of the first scraping strip (53), and a driving mechanism for driving the sliding block (51) to lift is arranged on the side wall of the vertical plate (4); A second cutting assembly, the second cutting assembly is used to cut the inner wall of the plastic pipe (2), the second cutting assembly includes a square pipe (6), the square pipe (6) penetrates and is fixedly installed between the two vertical sections of the wide pitch of the limiting groove (41), two limiting columns (61) are fixedly installed between the top wall and the bottom wall of the square pipe (6), two lifting plates (62) are slidably installed between the two limiting columns (61), a second L-shaped rod (63) is fixedly installed on one side of each of the two lifting plates (62) close to the mounting seat (33), a second scraping strip (64) is fixedly installed at one end of the second L-shaped rod (63) close to the mounting seat (33), and a second cutting knife (65) is arranged on one side of each of the two second scraping strips (64) away from each other; A screw rod (7), the screw rod (7) penetrates and is rotatably installed at the top end and the bottom end of the square pipe (6), and a driving assembly for driving the rotation of the screw rod (7) is arranged at the bottom end of the square pipe (6).

2. A cutting device for plastic testing thin sheet samples according to claim 1, characterized in that: A plurality of support feet (11) are arranged at the bottom end of the bottom plate (1), the front view of the support feet (11) is arranged in an inverted T shape, and a rubber pad is arranged at the bottom end of the support feet (11).

3. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: The two linear guide rails (31) are electrically connected through a controller, the two linear guide rails (31) are respectively arranged in parallel with the plastic pipe (2), the three-jaw chuck (34) is composed of a chuck body, three movable jaws and a driving mechanism, and the three-jaw chuck (34) realizes the clamping and positioning of the workpiece through the radial movement of the jaws.

4. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: A limiting groove (41) is arranged on the side wall of the vertical plate (4), the limiting groove (41) is arranged in a "convex" shape, the sliding block (51) is arranged in a "soil" shape, and the sliding block (51) is slidably connected with the vertical plate (4) through the limiting groove (41).

5. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: Two first limiting strips (55) are arranged at the bottom end of the first scraper strip (53), the end surfaces of the two first limiting strips (55) are arranged in a fan shape, the two first limiting strips (55) are arranged symmetrically with respect to the first scraper (54), and the distance between the first limiting strip (55) and the outer wall of the plastic tube (2) is smaller than the distance between the blade of the first scraper (54) and the outer wall of the plastic tube (2).

6. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: The driving mechanism comprises a pneumatic cylinder (56), the pneumatic cylinder (56) being mounted on a side wall of the vertical plate (4), and the bottom end of a piston rod of the pneumatic cylinder (56) being fixedly connected to the top end of a sliding block (51).

7. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: The two second scraping strips (64) are symmetrically arranged about the central axis of the plastic tube (2), and the distance between the top of the second scraping strip (64) located at the top and the central axis of the plastic tube (2) is less than the inner diameter of the plastic tube (2).

8. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: A second limiting strip (66) is provided on the side away from each other of the two second scraping strips (64); the two second limiting strips (66) are symmetrically arranged with respect to the adjacent second scraper (65); the end surface of the second limiting strip (66) is arranged in a fan shape; and the distance between the second limiting strip (66) and the inner wall of the plastic tube (2) is smaller than the distance between the blade of the second scraper (65) and the inner wall of the plastic tube (2).

9. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: The side wall of the screw rod (7) is provided with two sections of threads with opposite rotation directions and the same pitch, and the two lifting plates (62) are respectively matched with adjacent threads.

10. A cutting device for plastic testing thin-sheet samples according to claim 1, characterized in that: The driving assembly comprises a U-shaped block (71), the U-shaped block (71) being fixedly mounted on an outer wall of one side of the vertical plate (4), a reduction box (72) being fixedly mounted on the top end of the U-shaped block (71), an output shaft of the reduction box (72) being fixedly connected to the screw rod (7) via a coupling, and a servo motor (73) being fixedly mounted on the bottom end of the U-shaped block (71), an output shaft of the servo motor (73) being fixedly connected to an input shaft of the reduction box (72) via a coupling.

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