Abnormal crystal point detection fixture for co-extruded film and crystal point detection method for co-extruded film

Abstract

The present invention provides a co-extruded film abnormal crystal point detection fixture, comprising a first mold and a second mold; the first mold and the second mold both have a mold clamping plane, a slicing plane located on the upper side and a placement plane located on the lower side, the mold clamping plane is perpendicular to the slicing plane and the placement plane, and the mold clamping plane is provided with a groove that runs through the upper surface and the lower surface of the mold; when the first mold and the second mold are molded, the two slicing planes are coplanar, the first mold and the second mold are molded so that the film to be detected is clamped between the mold clamping planes of the two, and the two grooves relatively form an observation channel for observing the area to be detected; the present invention also provides a co-extruded film crystal point detection method using the above-mentioned co-extruded film abnormal crystal point detection fixture. The co-extruded film abnormal crystal point detection fixture of the present invention facilitates production personnel to further confirm in which material layer the crystal points in the co-extruded film are located.

Description

Technical Field

[0001] The invention relates to the field of co-extruded film crystal point detection, in particular to a co-extruded film abnormal crystal point detection fixture and a co-extruded film crystal point detection method. Background Art

[0002] Co-extruded film is made of multiple materials processed into different material layers by a multi-channel heated co-extruder and then compounded into an integrated film. During the processing, the materials in the material layer will be over-polymerized to form "crystal points" (cross-linked crystal points, oxidized crystal points, unmelted crystal points and impurity crystal points, etc.). In addition to causing appearance defects of the co-extruded film, it will also affect the subsequent printing, compounding or molding of the co-extruded film. Therefore, it is necessary to conduct random inspections on the co-extruded film during the production process to avoid too many "crystal points" in the co-extruded film. The existing crystal point detection method is to take a flat co-extruded film sample, and then use a light source to irradiate the co-extruded film from the bottom to the top, and the production staff observes from above the co-extruded film. Co-extruded film, determine the "crystal point" situation on the co-extruded film, but this crystal point detection method can only know whether there are "crystal points" on the co-extruded film, but cannot know which material layer the "crystal points" are located in, resulting in the inability to accurately adjust the processing parameters of a specific heating channel on a multi-channel heated co-extruder to eliminate the abnormal "crystal points" on the co-extruded film, and it is impossible to rule out whether the "crystal points" are caused by raw material problems or equipment problems. Therefore, there is an urgent need for a device that is convenient for production personnel to fix the sample to cut open the crystal point and determine the material layer where the crystal point of the co-extruded film is located, so that subsequent production personnel can obtain high-quality products by replacing raw materials and / or adjusting equipment parameters. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem that there is a lack of devices on the market that are convenient for production personnel to fix samples to split the crystal points, and to provide a co-extruded film abnormal crystal point detection fixture, which is convenient for production personnel to fix samples to split the crystal points, so as to further confirm in which material layer the crystal points in the co-extruded film are located.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A co-extruded film abnormal crystal point detection fixture comprises a first mold and a second mold; the first mold has a first mold-joining plane, a first slicing plane located on the upper side and a first placement plane located on the lower side, the first mold-joining plane is perpendicular to the first slicing plane and the first placement plane, and the first mold-joining plane is provided with a first groove running through the upper surface and the lower surface of the first mold; the second mold has a second mold-joining plane, a second slicing plane located on the upper side and a second placement plane located on the lower side, the second mold-joining plane is perpendicular to the second slicing plane and the second placement plane, and the second mold-joining plane is provided with a second groove running through the upper surface and the lower surface of the second mold; when the first mold and the second mold are joined, the first slicing plane and the second slicing plane are coplanar, and the first mold and the second mold are joined so that the film to be detected is clamped between the two mold-joining planes, and the first groove and the second groove relatively form an observation channel for observing the area to be detected.

[0006] Compared with the prior art, the abnormal crystal point detection fixture of the co-extruded film of the present invention is used to fix the film to be tested to prevent the film to be tested from shifting during slicing and observation, so that the crystal point area of ​​the film to be tested is located in the observation channel, and the crystal point area is located at the outer edge of the observation channel, and then the crystal point is cut open by slicing the cross section of the film cutting blade, and after adding an auxiliary light source below the observation channel, a microscope is used to confirm the specific position of the crystal point from above the observation channel, so that production personnel can quickly and accurately confirm in which material layer the crystal point on the film to be tested cut from the co-extruded film is located, which is of great significance for selecting raw materials, improving the production process of multi-layer co-extruded films and improving the quality of multi-layer co-extruded films; in addition, the mold planes of the two molds are required to be perpendicular to the slicing plane and the placement plane, so as to ensure that the observation channel is vertically arranged relative to the slicing plane and the placement plane to ensure detection accuracy.

[0007] Furthermore, the horizontality of the first slicing plane, the first placement plane, the second slicing plane and the second placement plane are all within a range of ±0.02 mm / m to 0.05 mm / m.

[0008] When the film cutting blade slices the film to be tested, the upper surface of the mold needs to be used as the reference starting point. The upper surface of the mold has a high levelness, thereby ensuring the flatness of the cross-section of the film to be tested after slicing, and ensuring subsequent observation and measurement results; the lower surface of the mold has a high levelness, which can ensure that when the fixture is placed on a horizontal operating table, the upper surface of the fixture remains parallel to the horizontal plane, avoiding the fixture from tilting relative to the horizontal plane and affecting the light entry of the auxiliary light source and microscope observation.

[0009] Another object of the present invention is to provide a co-extruded film crystal point detection method using the above-mentioned co-extruded film abnormal crystal point detection fixture, comprising:

[0010] Sampling: Cut off an area with crystal points on the co-extruded film as the film to be tested;

[0011] Fixing the film to be tested: fixing the film to be tested between the mold planes of the first mold and the second mold, and the crystal point area of ​​the film to be tested is located at the junction of the observation channel and the outer side of the fixture;

[0012] Cutting the film to be tested: using a film cutting blade to cut the crystal point area located at the junction of the observation channel and the outside of the fixture, so that the crystal point is cut open;

[0013] Find abnormal areas: Use a microscope to determine the location of abnormal thickness of the film to be tested, and determine the material layer with abnormal thickness;

[0014] Locating crystal points: Using a microscope to determine whether there are inhomogeneous particles in a layer of material with abnormal thickness;

[0015] Repeated detection: intercept multiple films to be detected for detection, and count the detection results of multiple films to be detected.

[0016] Beneficial effect: The existing method for eliminating crystal points is that after the production personnel observe the crystal points on the co-extruded film, they first eliminate the raw material problem (by replacing different batches of raw materials layer by layer to observe the improvement of the crystal points), and then eliminate the equipment problem (by changing the process parameters of the extruder, observing the change of the crystal points, to determine which material layer the abnormal crystal points are generated in); the process of eliminating the raw material problem is time-consuming, consumes a lot of materials, and produces a large number of defective products; the process of eliminating the equipment problem is time-consuming, and the co-extruded film produced after the extruder processing parameters are adjusted may introduce new problems of generating crystal points due to excessive heating time and changes in viscosity, affecting the production personnel Judgment of the original production process; Compared with the prior art, a co-extruded film crystal point detection method of the present invention, by using a co-extruded film abnormal crystal point detection fixture, a film slicing knife and a microscope, analyzes the area containing crystal points on the multi-layer co-extruded film, determines the material layer where the crystal points are located, and after analyzing multiple representative films to be detected, by counting the positions of the material layers where the crystal points mainly appear, it is convenient to make targeted adjustments to the extrusion process of the material layer and the raw materials, thereby greatly shortening the product debugging time, effectively improving the product appearance, and is of great significance to the production of multi-layer co-extruded films with stable quality.

[0017] Further, the sampling steps include:

[0018] Determine the location of the crystal points on the co-extruded film by observing the appearance of the co-extruded film;

[0019] The Amm x Bmm area in the middle where the cutting crystal point is located is used as the film to be tested, where A and B are greater than 10 and not greater than 200.

[0020] During the sampling process, the area with the crystal point in the middle is cut off as the film to be tested, so that there is enough distance between the crystal point and the edge of the film to be tested, which is convenient for adjusting the position of the film to be tested in multiple directions when fixing the film to be tested so as to place the crystal point in the observation channel.

[0021] Furthermore, the step of fixing the film to be tested includes:

[0022] The film to be tested is placed between the first mold and the second mold, and the crystal point area of ​​the film to be tested is located at the junction of the observation channel and the outer side of the fixture;

[0023] The first mold and the second mold are molded together;

[0024] The fixing member is used to fix the relative positions of the first mold and the second mold so that the first mold and the second mold clamp the film to be tested.

[0025] Furthermore, the step of fixing the film to be tested also includes:

[0026] After fixing the first mold and the second mold, detect whether the upper surfaces of the first mold and the second mold are located on the same horizontal plane. If not, adjust the relative positions of the first mold and the second mold in the vertical direction; if so, detect whether the first mold and the second mold are not aligned. If not, determine that a crystal point is located in the mold closing plane of the first mold and the second mold, causing the first mold and the second mold to be misaligned, and adjust the position of the film to be detected.

[0027] The step of fixing the film to be tested also includes position correction of the two molds and position correction of the film to be tested; if the upper surfaces of the first mold and the second mold are not located on the same horizontal plane, it means that the first mold and the second mold are relatively tilted, resulting in the observation channel being tilted relative to the horizontal plane, and the film to be tested clamped by the first mold and the second mold being tilted relative to the horizontal plane, affecting the subsequent slicing effect of the film to be tested, as well as the observation and detection of the film to be tested after slicing; if the first mold and the second mold are not aligned, it means that the crystal point is not located in the mold closing plane (the thickness at the crystal point is much thicker than the thickness at the normal position of the co-extruded film), resulting in the first mold and the second mold being misaligned when the first mold and the second mold are relatively fixed and clamped to the film to be tested, thereby affecting the slicing effect and observation results of the film to be tested.

[0028] Furthermore, the step of cutting the film to be tested includes:

[0029] The blade of the film cutting blade is close to the upper surface of the fixture;

[0030] The film cutting blade moves obliquely at an angle of 20-50° relative to the plane where the clamping plane is located to cut the film to be tested.

[0031] The above configuration has the following beneficial effects:

[0032] (1) Since the accuracy of material layer thickness measurement will affect the subsequent search for abnormal areas, if the film cutting blade moves in a direction perpendicular to the clamping plane during cutting (the film cutting blade moves horizontally and linearly to cut the film to be tested), the blade will produce friction lines with the film cross section in the same direction as the movement direction during the movement (the line is parallel to the boundary line between the layers), thereby affecting the identification of the boundary line between the layers and the measurement of the material layer thickness; therefore, it is necessary that the blade cutting mark (cutting movement route) of the film cross section to be tested maintains a certain angle with the cutting interface of the film to be tested, so that the friction lines generated by the blade and the film cross section and the boundary line between the layers form a corresponding angle, thereby not affecting the identification of the boundary line between the layers, ensuring a high accuracy when measuring the material layer thickness;

[0033] (2) The film cutting blade slices at an angle of 20-50° relative to the plane where the clamping plane is located. Therefore, when the film cutting blade cuts, different positions of the film cutting blade contact and cut different positions of the film to be tested, effectively reducing the jagged lines at the edge of the cross section of the film to be tested, improving the clarity of the material layer boundary, and facilitating observation.

[0034] Furthermore, in the process of searching for abnormal areas, if the film thickness at one position is more than 40% thicker than the film thickness at an adjacent position, then the position is judged to be a position with abnormal thickness; the position with abnormal thickness is observed, and if the thickness at one position in the material layer is more than 40% thicker than the thickness of the same material layer at an adjacent position, then the material layer is judged to be a material layer with abnormal thickness.

[0035] Since the molecular weight in the crystal point region is higher than that in the surrounding region, the position of the material layer where the crystal point is located can be directly located by directly observing the thickness change of the film to be tested and the thickness change of the material layer.

[0036] Furthermore, the microscope is a metallographic microscope whose eyepiece can be connected to an electronic display device.

[0037] A metallographic microscope is an optical microscope that can be used to observe the microstructure, low-magnification structure and fracture structure of materials, so that metallographic images can be directly observed and metallographic maps can be analyzed. After its eyepiece is connected to the electronic display device, it is convenient for production personnel to observe and measure various indicators of the film to be tested.

[0038] Furthermore, the objective lens magnification of the microscope is 5-50 times.

[0039] The objective lens of the microscope has a wide range of magnifications, which makes it easy for production personnel to select appropriate magnifications and focal lengths for observation. In addition, the magnification of the objective lens of the microscope is limited to 5-50 times, thereby avoiding the situation where the magnification of the objective lens is too small, resulting in the production personnel being unable to distinguish the boundaries between material layers and accurately measure changes in layer thickness during observation, and avoiding the situation where the magnification is too large, resulting in the displayed image exceeding the boundary of the viewing screen, making it impossible to observe the film as a whole and effectively measure the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the fixture;

[0041] Figure 2 is a top view of the fixture;

[0042] Figure 3 This is an exploded view of the fixture;

[0043] Figure 4 It is a cross-sectional view of the observation channel after the fixture clamps the cut film to be tested;

[0044] Figure 5 It is a cross-sectional view of the end of the cut film to be tested after the clamp clamps it;

[0045] Figure 6 It is a schematic diagram of the moving direction of the film cutting blade;

[0046] Figure 7 It is an observation picture of abnormal areas found under a microscope;

[0047] Figure 8 This is an observation picture of crystal points found under a microscope.

[0048] Description of labels:

[0049] Fixture 1, first mold 10, first mold plane 11, first slicing plane 12, first placement plane 13, first groove 14, second mold 2, second mold plane 21, second slicing plane 22, second placement plane 23, second groove 24, observation channel 3, fixing part 4, microscope 5, film to be tested 6. DETAILED DESCRIPTION

[0050] The following describes the embodiments of the present invention in conjunction with the accompanying drawings:

[0051] Embodiment 1

[0052] See also Figures 1 to 5 The co-extruded film abnormal crystal point detection device of this embodiment includes a co-extruded film abnormal crystal point detection fixture 1 (hereinafter referred to as fixture 1), a film cutting blade (not shown in the figure) and a microscope 5.

[0053] The fixture 1 includes a first mold 10 and a second mold 2; the first mold 10 has a first mold-matching plane 11, a first slicing plane 12 located on the upper side and a first placement plane 13 located on the lower side, the first mold-matching plane 11 is perpendicular to the first slicing plane 12 and the first placement plane 13, and the first mold-matching plane 11 is provided with a first groove 14 that passes through the upper surface and the lower surface of the first mold 10; the second mold 2 has a second mold-matching plane 21, a second slicing plane 22 located on the upper side and a second placement plane 23 located on the lower side, the second mold-matching plane 21 is perpendicular to the second slicing plane 22 and the second placement plane 23, and the second mold-matching plane 21 is provided with a second groove 24 that passes through the upper surface and the lower surface of the second mold 2; when the first mold 10 and the second mold 2 are molded together, the first slicing plane 12 and the second slicing plane 22 are coplanar, and the first mold 10 and the second mold 2 are molded together so that the film 6 to be detected is clamped between the mold-matching planes of the two, and the first groove 14 and the second groove 24 relatively form an observation channel 3 for observing the area to be detected.

[0054] See also Figure 2 and Figure 4 The caliber of the observation channel 3 is not less than 20 mm.

[0055] See also Figure 4 The horizontal degrees of the first slicing plane 12, the first placement plane 13, the second slicing plane 22 and the second placement plane 23 are all ±0.02 mm / m to 0.05 mm / m.

[0056] In the process of slicing the film 6 to be tested, the film cutting blade needs to use the upper surface of the mold as the reference starting point. The upper surface of the mold has a high levelness, so as to ensure the flatness of the cross-section of the film 6 to be tested after slicing, and ensure the subsequent observation and measurement results; the lower surface of the fixture 1 has a high levelness, which can ensure that when the fixture 1 is placed on a horizontal operating table, the upper surface of the fixture 1 remains parallel to the horizontal plane, avoiding the fixture 1 from tilting relative to the horizontal plane and affecting the light entry of the auxiliary light source and the observation of the microscope 5.

[0057] See also Figure 5 The horizontality of the first mold plane 11 and the second mold plane 21 is ±0.02-0.05 mm / m, thereby ensuring that the first mold plane 11 and the second mold plane 21 are parallel to each other, and after the clamp 1 is molded, the first mold plane 11 and the second mold plane 21 are perpendicular to the horizontal plane, ensuring that after the first mold 10 and the second mold 2 clamp the film 6 to be detected, the film 6 to be detected is perpendicular to the horizontal plane, thereby improving the observation accuracy.

[0058] mm / m is the unit of levelness. For example, 1mm / m means that when a strip level is placed on a specific plane of an object (the production specification of the object is 1m high), the error on both sides of the specific plane of the object is 1mm (common knowledge).

[0059] Compared with the prior art, the abnormal crystal point detection fixture 1 of the co-extruded film of the present invention is used to fix the film 6 to be tested to prevent the film 6 to be tested from shifting during slicing and observation, so that the crystal point area of ​​the film 6 to be tested is located in the observation channel 3, and the crystal point area is located at the outer edge of the observation channel 3, and then the crystal point is cut open by slicing the cross section of the film cutting blade, and an auxiliary light source is added below the observation channel 3 (it can be omitted when there is sufficient external light), and then the specific position of the crystal point is confirmed from above the observation channel 3 using a microscope 5, so that production personnel can quickly and accurately confirm in which material layer the crystal point on the film 6 to be tested cut from the co-extruded film is located, which is of great significance for selecting raw materials, improving the production process of multi-layer co-extruded films and improving the quality of multi-layer co-extruded films; in addition, the mold planes of the two molds are required to be perpendicular to the slicing plane and the placement plane, so as to ensure that the observation channel 3 is vertically arranged relative to the slicing plane and the placement plane to ensure detection accuracy.

[0060] See also Figure 4 , the microscope 5 is a metallographic microscope whose eyepiece can be connected to an electronic display device.

[0061] The metallographic microscope is an optical microscope that can observe the microstructure, low-magnification structure and fracture structure of materials, so that the metallographic image can be directly observed and the metallographic spectrum can be analyzed. After its eyepiece is connected to the electronic display device, it is convenient for production personnel to observe and measure various indicators of the film 6 to be tested.

[0062] The objective lens magnification of the microscope 5 is 5-50 times.

[0063] The objective lens of the microscope 5 has a wide range of magnifications, which makes it easy for production personnel to select appropriate magnifications and focal lengths for observation. In addition, the magnification of the objective lens of the microscope 5 is limited to 5-50 times, thereby avoiding the situation where the objective lens magnification is too small, resulting in the production personnel being unable to distinguish the boundaries between the material layers and accurately measure the thickness changes during observation, and avoiding the situation where the magnification is too large, resulting in the displayed image exceeding the boundary of the screen, making it impossible to observe the film as a whole and effectively measure the film.

[0064] The eyepiece is located above the microscope and can be observed with the eyes or connected to a computer. The objective lens is the lens close to the object being observed.

[0065] Embodiment 2

[0066] See also Figures 5 and 6Another object of the present invention is to provide a co-extruded film crystal point detection method using the above-mentioned co-extruded film abnormal crystal point detection device, comprising:

[0067] Sampling: Cut off an area with crystal points on the co-extruded film as the film to be tested;

[0068] Fixing the film to be tested: fixing the film to be tested between the mold planes of the first mold and the second mold, and the crystal point area of ​​the film to be tested is located at the junction of the observation channel and the outer side of the fixture;

[0069] Cutting the film to be tested: using a film cutting blade to cut the crystal point area located at the junction of the observation channel and the outside of the fixture, so that the crystal point is cut open;

[0070] Find abnormal areas: Use a microscope to determine the location of abnormal thickness of the film to be tested, and determine the material layer with abnormal thickness;

[0071] Locating crystal points: Using a microscope to determine whether there are inhomogeneous particles in a layer of material with abnormal thickness;

[0072] Repeated detection: intercept multiple films to be detected for detection, and count the detection results of multiple films to be detected.

[0073] The steps for sampling include:

[0074] Determine the location of the crystal points on the co-extruded film by observing the appearance of the co-extruded film;

[0075] The Amm x Bmm area in the middle where the cutting crystal point is located is used as the film to be tested, where A and B are greater than 10 and not greater than 200.

[0076] During the sampling process, the area with the crystal point in the middle is cut off as the film to be tested, so that there is enough distance between the crystal point and the edge of the film to be tested, which is convenient for adjusting the position of the film to be tested in multiple directions when fixing the film to be tested so as to place the crystal point in the observation channel.

[0077] The steps for fixing the film to be tested include:

[0078] The film to be tested is placed between the first mold and the second mold, and the crystal point area of ​​the film to be tested is located at the junction of the observation channel and the outer side of the fixture;

[0079] The first mold and the second mold are molded together;

[0080] The fixing member is used to fix the relative positions of the first mold and the second mold so that the first mold and the second mold clamp the film to be tested.

[0081] The step of fixing the film to be tested also includes:

[0082] After fixing the first mold and the second mold, detect whether the upper surfaces of the first mold and the second mold are located on the same horizontal plane. If not, adjust the relative positions of the first mold and the second mold in the vertical direction; if so, detect whether the first mold and the second mold are not aligned. If not, determine that a crystal point is located in the mold closing plane of the first mold and the second mold, causing the first mold and the second mold to be misaligned, and adjust the position of the film to be detected.

[0083] Specifically, the method for detecting whether the upper surfaces of the first mold and the second mold are located in the same horizontal plane is as follows: after the first mold and the second mold are closed, the lower surface of the fixture is placed on a horizontal operating table, and a strip level is used to test whether the upper surfaces of the first mold and the second mold are located in the same horizontal plane. The method for detecting whether the first mold and the second mold are not aligned is as follows: after the first mold and the second mold are closed, the fixture is erected with the end facing upwards, and a strip level is used to test whether the ends of the first mold and the second mold are located in the same horizontal plane.

[0084] The step of fixing the film to be tested also includes position correction of the two molds and position correction of the film to be tested; if the upper surfaces of the first mold and the second mold are not located on the same horizontal plane, it means that the first mold and the second mold are relatively tilted, resulting in the observation channel being tilted relative to the horizontal plane, and the film to be tested clamped by the first mold and the second mold being tilted relative to the horizontal plane, affecting the subsequent slicing effect of the film to be tested, as well as the observation and detection of the film to be tested after slicing; if the first mold and the second mold are not aligned, it means that the crystal point is not located in the mold closing plane (the thickness at the crystal point is much thicker than the thickness at the normal position of the co-extruded film), resulting in the first mold and the second mold being misaligned when the first mold and the second mold are relatively fixed and clamped to the film to be tested, thereby affecting the slicing effect and observation results of the film to be tested.

[0085] See also Figure 6 , Figure 6 The dark dots in the observation channel represent crystal points, and the arrows represent the moving direction of the film cutting blade. The steps of cutting the film to be tested include:

[0086] The blade of the film cutting blade is close to the upper surface of the fixture;

[0087] The film cutting blade moves obliquely at an angle of 20-50° relative to the plane where the clamping plane is located to cut the film to be tested.

[0088] The above configuration has the following beneficial effects:

[0089] (1) Since the accuracy of material layer thickness measurement will affect the subsequent search for abnormal areas, if the film cutting blade moves in a direction perpendicular to the clamping plane during cutting (the film cutting blade moves horizontally and linearly to cut the film to be tested), the blade will produce friction lines with the film cross section in the same direction as the movement direction during the movement (the line is parallel to the boundary line between the layers), thereby affecting the identification of the boundary line between the layers and the measurement of the material layer thickness; therefore, it is necessary that the blade cutting mark (cutting movement route) of the film cross section to be tested maintains a certain angle with the cutting interface of the film to be tested, so that the friction lines generated by the blade and the film cross section and the boundary line between the layers form a corresponding angle, thereby not affecting the identification of the boundary line between the layers, ensuring a high accuracy when measuring the material layer thickness;

[0090] (2) The film cutting blade slices at an angle of 20-50° relative to the plane where the clamping plane is located. Therefore, when the film cutting blade cuts, different positions of the film cutting blade contact and cut different positions of the film to be tested, effectively reducing the jagged lines at the edge of the cross section of the film to be tested, improving the clarity of the material layer boundary, and facilitating observation.

[0091] When searching for abnormal areas, place the film to be tested under a microscope, adjust the lens of the microscope to a suitable focal length, and observe the thickness changes of each layer of the film to be tested, as well as the difference between the crystal point position and the normal position.

[0092] In the process of searching for abnormal areas, if the film thickness at one position is thicker than the film thickness at an adjacent position by more than 40%, then the position is judged to be a position with abnormal thickness; the position with abnormal thickness is observed, and if the thickness at one position in the material layer is thicker than the thickness of the same material layer at an adjacent position by more than 40%, then the material layer is judged to be a material layer with abnormal thickness.

[0093] Since the processing parameters of the co-extruder will fluctuate during operation, the thickness of the material layer will change within a certain thickness range. Therefore, "film thickness increases by more than 40%" is used as the selection condition for the position of abnormal thickness, thereby eliminating the interference of the position with increased thickness caused by the fluctuation of the processing parameters of the co-extruder.

[0094] Since the molecular weight in the crystal point region is higher than that in the surrounding region, the position of the material layer where the crystal point is located can be directly located by directly observing the thickness change of the film to be tested and the thickness change of the material layer.

[0095] This embodiment of Figure 7 The image displayed on the display when an abnormal area is found is shown, in which it can be directly observed that there is an area with a thickness greater than other areas in the film to be tested (marked by arrow); Figure 8The image displayed on the monitor when the crystal point is found after the abnormal area is found is shown, in which it can be directly observed that there is an area with an obvious abnormal increase in thickness in a material layer in the film to be tested (marked by an arrow). When looking for abnormal areas and locating crystal points, the lens adjustment range of the microscope is close (after finding the abnormal area, fine-tune the lens to accurately observe the crystal point), and the crystal point is found by moving the position of the fixture relative to the microscope.

[0096] Beneficial effect: The existing method for eliminating crystal points is that after the production personnel observe the crystal points on the co-extruded film, they first eliminate the raw material problem (by replacing different batches of raw materials layer by layer to observe the improvement of the crystal points), and then eliminate the equipment problem (by changing the process parameters of the extruder, observing the change of the crystal points, to determine which material layer the abnormal crystal points are generated in); the process of eliminating the raw material problem is time-consuming, consumes a lot of materials, and produces a large number of defective products; the process of eliminating the equipment problem is time-consuming, and the co-extruded film produced after the extruder processing parameters are adjusted may introduce new problems of generating crystal points due to excessive heating time and changes in viscosity, affecting the production personnel Judgment of the original production process; Compared with the prior art, a co-extruded film crystal point detection method of the present invention, by using a co-extruded film abnormal crystal point detection fixture, a film slicing knife and a microscope, analyzes the area containing crystal points on the multi-layer co-extruded film, determines the material layer where the crystal points are located, and after analyzing multiple representative films to be detected, by counting the positions of the material layers where the crystal points mainly appear, it is convenient to make targeted adjustments to the extrusion process of the material layer and the raw materials, thereby greatly shortening the product debugging time, effectively improving the product appearance, and is of great significance to the production of multi-layer co-extruded films with stable quality.

[0097] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A method for detecting crystal points of a co-extruded film, which uses a co-extruded film abnormal crystal point detection fixture, the co-extruded film abnormal crystal point detection fixture comprising: The first mold has a first mold-matching plane, a first slicing plane located on the upper side, and a first placement plane located on the lower side, the first mold-matching plane is perpendicular to the first slicing plane and the first placement plane, and the first mold-matching plane is provided with a first groove penetrating the upper surface and the lower surface of the first mold; The second mold has a second mold-matching plane, a second slicing plane located on the upper side, and a second placement plane located on the lower side, the second mold-matching plane is perpendicular to the second slicing plane and the second placement plane, and the second mold-matching plane is provided with a second groove running through the upper surface and the lower surface of the second mold; When the first mold and the second mold are molded together, the first slicing plane and the second slicing plane are coplanar, the first mold and the second mold are molded together so that the film to be inspected is clamped between the mold planes of the two, and the first groove and the second groove are relatively formed to form an observation channel for observing the area to be inspected; Detection methods include: Sampling: Cut off an area with crystal points on the co-extruded film as the film to be tested; Fixing the film to be tested: fixing the film to be tested between the mold planes of the first mold and the second mold, and the crystal point area of ​​the film to be tested is located at the junction of the observation channel and the outer side of the fixture; Cutting the film to be tested: using a film cutting blade to cut the crystal point area located at the junction of the observation channel and the outside of the fixture, so that the crystal point is cut open; Find abnormal areas: Use a microscope to determine the location of abnormal thickness of the film to be tested, and determine the material layer with abnormal thickness; Locating crystal points: Using a microscope to determine whether there are inhomogeneous particles in a layer of material with abnormal thickness; Repeated testing: Cut multiple films to be tested for analysis.

2. The co-extruded film crystal point detection method according to claim 1, characterized in that: The horizontality of the first slicing plane, the first placement plane, the second slicing plane and the second placement plane are all ±0.02 mm / m to 0.05 mm / m.

3. The co-extruded film crystal point detection method according to claim 1, characterized in that: The steps for sampling include: Determine the location of the crystal points on the co-extruded film by observing the appearance of the co-extruded film; The Amm x Bmm area in the middle where the cutting crystal point is located is used as the film to be tested, where A and B are greater than 10 and not greater than 200.

4. The co-extruded film crystal point detection method according to claim 1, characterized in that: The steps for fixing the film to be tested include: The film to be tested is placed between the first mold and the second mold, and the crystal point area of ​​the film to be tested is located at the junction of the observation channel and the outer side of the fixture; The first mold and the second mold are molded together; The fixing member is used to fix the relative positions of the first mold and the second mold so that the first mold and the second mold clamp the film to be tested.

5. The co-extruded film crystal point detection method according to claim 4, characterized in that: The step of fixing the film to be tested also includes: After fixing the first mold and the second mold, detect whether the upper surfaces of the first mold and the second mold are located on the same horizontal plane. If not, adjust the relative positions of the first mold and the second mold in the vertical direction; if so, detect whether the first mold and the second mold are not aligned. If not, determine that a crystal point is located in the mold closing plane of the first mold and the second mold, causing the first mold and the second mold to be misaligned, and adjust the position of the film to be detected.

6. The co-extruded film crystal point detection method according to claim 1, characterized in that: The steps for cutting the film to be tested include: The blade of the film cutting blade is close to the upper surface of the fixture; The film cutting blade moves obliquely at an angle of 20-50° relative to the plane where the clamping plane is located to cut the film to be tested.

7. The co-extruded film crystal point detection method according to claim 1, characterized in that: In the process of searching for abnormal areas, if the film thickness at one position is thicker than the film thickness at an adjacent position by more than 40%, then the position is judged to be a position with abnormal thickness; the position with abnormal thickness is observed, and if the thickness at one position in the material layer is thicker than the thickness of the same material layer at an adjacent position by more than 40%, then the material layer is judged to be a material layer with abnormal thickness.

8. The co-extruded film crystal point detection method according to claim 1, characterized in that: The microscope is a metallographic microscope whose eyepiece can be connected to an electronic display device.

9. The co-extruded film crystal point detection method according to claim 1, characterized in that: The objective lens magnification of the microscope is 5-50 times.

Images