A method for testing the tensile properties of roll film material

Abstract

This invention relates to a method for testing the tensile properties of rolled film materials. First, the basic information of the film roll to be tested is registered. The roll is divided into diameter layers based on its initial outer diameter, core tube outer diameter, and unwound length, and a test segment is selected at each diameter layer. The test segment is led out and the front and rear clamping areas are fixed. Width-direction test positions and test marks are set according to the effective width of the film material. A leveling load is applied, and the flatness of the film surface, clamping status, unwinding resistance, and test mark status are verified. Multiple levels of test load are applied sequentially along the length of the film material, and the test mark positions are read after loading, holding, and recovery. Test records corresponding to clamping slippage, clamping torsion, unwinding fluctuation, and mark abnormalities are excluded, and valid test records are registered according to the roll diameter layer and width-direction test position. This method is used for testing the tensile properties of rolled film materials before loading onto the machine.

Description

Technical Field

[0001] This invention relates to the field of film material performance testing technology, specifically a method for testing the tensile properties of rolled film materials. Background Technology

[0002] Rolled film stock is typically supplied in whole rolls to packaging, coating, laminating, die-cutting, and slitting equipment. During film preparation, traction, cooling, winding, storage, and transfer, the outer, middle, and inner layers of the same roll may exhibit different winding states; similarly, along the same width, the edge and middle areas may differ in tightness due to variations in winding tension, edge thickness, and roller contact conditions. These differences may not be immediately apparent during static visual inspection, but they can easily manifest as edge wrinkling, localized elongation, serpentine deviation, misalignment, or insufficient shrinkage during subsequent traction, printing, laminating, or die-cutting.

[0003] Current methods for testing the tensile properties of thin films primarily employ cut-sample tensile tests, obtaining parameters such as tensile strength, elongation at break, and elastic modulus from standard specimens. While this method can evaluate the basic mechanical properties of material specimens, once the specimens are cut, they are no longer in their original roll state, and their roll diameter, interlayer pressure, width-direction tension differences, and winding history within the film roll cannot be preserved. For roll-form film materials, subsequent processing anomalies are often not due to insufficient overall roll strength, but rather to excessive residual elongation or insufficient elastic recovery in a specific width band, layer, or continuous segment of the film.

[0004] Another method involves manually tightening the membrane material or loading it onto a winding shaft after it has been drawn out, observing changes in membrane markings, edge positions, or flatness. While this method more closely approximates the rolled-up usage state, the test results are easily affected by initial slack, clamping skew, winding shaft parallelism, and fluctuations in unwinding resistance. After detecting marking displacement, it is difficult to determine whether the displacement originates from the membrane material's own tensile deformation, or from clamping torsion, initial wrinkle release, or instantaneous changes in unwinding resistance.

[0005] Existing roll-to-roll equipment, with its tension sensing, floating roller feedback, web guiding, and winding / unwinding control, primarily aims to maintain stable tension during continuous operation. It cannot directly determine whether there is uneven stretching in the transverse direction, excessive residual elongation in certain areas, or insufficient recovery within the roll under test. Furthermore, recording only a single displacement during loading cannot distinguish between recoverable elongation and residual elongation after unloading.

[0006] Therefore, the specific problem that still needs to be solved in the tensile property testing of rolled membrane materials is: how to conduct corresponding tests on the tensile response of different roll diameter layers and different width positions of the same roll without damaging the overall use state of the roll, and to eliminate the apparent displacement caused by initial relaxation, clamping torsion and unwinding tension fluctuations, so as to stably identify membrane segments with inconsistent width tension, excessive local residual elongation and insufficient elastic recovery. Summary of the Invention

[0007] (a) Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention provides a method for detecting the tensile properties of roll-shaped membrane materials. This method has advantages such as corresponding detection of roll diameter layer position and width direction detection position, separate reading of multi-level detection load and unloading recovery, and simultaneous verification of initial stable state and apparent displacement exclusion state. It solves the problem that existing detection methods are unable to stably identify membrane segments with inconsistent width direction tension, excessive local residual elongation, and insufficient elastic recovery while maintaining the overall use state of the membrane roll.

[0009] (II) Technical Solution

[0010] To achieve the above objectives, the present invention provides the following technical solution: a method for detecting the tensile properties of roll film material, comprising:

[0011] S1. Register the basic information of the membrane roll to be tested, divide the roll diameter into layers according to the initial outer diameter of the membrane roll, the outer diameter of the core tube and the unwound length, and select the test segment in each roll diameter layer.

[0012] S2, extend the detection section and fix the front clamping area and the rear clamping area, set the width detection position according to the effective width of the film material, and set the detection mark at each width detection position;

[0013] S3, apply a leveling load to the detection section, and check the film surface flatness, clamping status, unwinding resistance status and detection mark status in sequence;

[0014] S4. Apply multiple levels of detection load to the detection section along the length of the membrane material. After each level of detection load is in place and maintained, read the detection mark position of each width detection position. Then unload and read the restored detection mark position.

[0015] S5. Exclude the detection records corresponding to clamping slippage, clamping twisting, unwinding fluctuation and marking abnormalities, and register valid detection records according to roll diameter layer and width detection position.

[0016] Furthermore, in S1, the basic information of the membrane roll to be tested is registered, including the membrane roll number, membrane material name, membrane material, effective width of the membrane material, nominal thickness of the membrane material, initial outer diameter of the membrane roll, outer diameter of the core tube, total length of the membrane roll, winding direction, front and back directions of the membrane material, rated operating tension for subsequent processing, maximum allowable tension, and testing station number.

[0017] Furthermore, in S1, the roll diameter layer is divided into outer layer inspection layer, middle layer inspection layer and inner layer inspection layer according to the initial outer diameter of the film roll, the outer diameter of the core tube and the unwound length. The inspection section avoids joints, splicing tape, obvious creases, contamination, edge damage, core tube fixing tape influence area and end face crushing area.

[0018] Furthermore, in S2, when the effective width of the membrane material is less than 300 mm, three width detection positions are set for the left side, the middle side, and the right side; when the effective width of the membrane material is between 300 mm and 1200 mm, five width detection positions are set for the left side, the left-middle side, the middle side, the right-middle side, and the right side; and when the effective width of the membrane material is greater than 1200 mm, seven width detection positions are set.

[0019] Furthermore, in S2, a front marker and a rear marker are set at each width detection position. A marking reference distance is formed between the front marker and the rear marker, which is 300 mm to 1000 mm and remains fixed within the same detection task.

[0020] Furthermore, in S3, the leveling load is 10% to 30% of the rated operating tension of subsequent processing. The leveling load is maintained for 5 to 30 seconds. When the change in the position of the detection mark between two adjacent readings is less than the pre-registered initial stability threshold of 0.05 mm to 0.30 mm, the verification of the flatness of the membrane surface is completed.

[0021] Furthermore, in S3, the clamping status verification reads the clamping boundary, clamping width, and position changes of the clamping area in the front and rear clamping areas; the unwinding resistance status verification reads the film roll support status, unwinding damping setting, end face contact status, and film roll rotation status; and the detection mark status verification reads the detection mark clarity status, adhesion status, and position reading status.

[0022] Furthermore, in S4, the multi-level detection loads are sequentially a first-level detection load, a second-level detection load, and a third-level detection load. The first-level detection load is 40% to 60% of the rated operating tension of the subsequent processing, the second-level detection load is 70% to 90% of the rated operating tension of the subsequent processing, and the third-level detection load is 100% to 120% of the rated operating tension of the subsequent processing. Moreover, the third-level detection load is less than 80% of the maximum allowable tension.

[0023] Furthermore, in S4, after each level of detection load reaches the set value, it is held for 2 to 5 seconds and the detection mark position after loading is read. It is held for another 10 to 30 seconds and the detection mark position after holding is read. After unloading to the leveling load, it is held for 10 to 120 seconds and the detection mark position after recovery is read.

[0024] Furthermore, in S5, valid test records are registered according to the membrane roll number, roll diameter layer number, test segment number, width-direction test position number, test load level, test mark position after loading, test mark position after holding, test mark position after recovery, initial stability record number, and exclusion verification conclusion.

[0025] Compared with the prior art, the present invention provides a method for detecting the tensile properties of rolled film material, which has the following beneficial effects:

[0026] 1. This invention first registers the basic information of the membrane roll to be tested and divides the roll diameter into layers. Then, it sets the width detection position and detection mark in each detection section. Subsequently, it verifies the flatness, clamping state, unwinding resistance state, and detection mark state of the membrane surface through a leveling load. Then, it applies multiple levels of detection load to the detection section and reads the detection mark position after loading, holding, and recovery. Finally, it excludes the detection records corresponding to clamping slippage, clamping torsion, unwinding fluctuation, and mark abnormalities. This allows the positional changes of different roll diameter layers and different width detection positions of the same membrane roll during the stress and recovery process to be recorded accordingly. Thus, the detection process no longer relies on the single-point tensile results after sample cutting, nor does it rely solely on the mark changes after manual tensioning to judge the membrane material state. It can form effective detection records corresponding to the membrane roll layer, width position, and detection load without damaging the overall use state of the membrane roll. This provides a stable basis for identifying membrane sections with inconsistent width tension, excessive local residual elongation, and insufficient elastic recovery.

[0027] 2. This invention separates the leveling load, multi-level detection load, and unloading recovery reading, and incorporates initial stability verification and exclusion verification into the same detection process. Before formal loading, the detection section completes initial relaxation release and detection status confirmation. During loading, the detection mark positions after each load level is in place and after holding are recorded respectively. After unloading, the recovered detection mark positions are read. This can distinguish the displacement changes of the detection section under force and the residual changes after unloading. For position changes caused by clamping area slippage, oblique clamping, unwinding jamming, end face friction, detection mark detachment, or reading abnormalities, they can be eliminated before effective detection records are formed. This reduces the situation where detection process errors are misjudged as abnormal tensile characteristics of the film material, and improves the correspondence between the quality judgment of the rolled film material before loading and the subsequent packaging, coating, lamination, and die-cutting processing status. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see Figure 1 A method for testing the tensile properties of roll film, comprising:

[0031] S1. Register the basic information of the membrane roll to be tested, divide the roll diameter into layers based on the initial outer diameter of the membrane roll, the outer diameter of the core tube, and the unwound length, and select the test segment at each roll diameter layer. The specific implementation is as follows:

[0032] Before testing, a basic information record should be established for the membrane rolls to be tested under the same testing task. The basic information record should include the membrane roll number, membrane material name, membrane material, effective width of membrane material, nominal thickness of membrane material, initial outer diameter of membrane roll, outer diameter of core tube, total length of membrane roll, winding direction, front and back directions of membrane material, name of subsequent processing equipment, rated operating tension of subsequent processing, maximum allowable tension, testing date, and testing station number.

[0033] The membrane roll number is used to group records formed by the same membrane roll at different roll diameter layers, different detection sections, and different width detection positions into the same detection task; the effective width of the membrane material is the width after deducting the waste edges, rough edges, and unusable edges on both sides; the nominal thickness of the membrane material is the thickness value registered in the material supply record, incoming material label, or detection task sheet; the initial outer diameter of the membrane roll is read before the start of detection, the outer diameter of the core tube is read in the membrane roll specification record, and the total length of the membrane roll is the length value in the incoming material record.

[0034] The inspection station first reads the initial outer diameter of the membrane roll and the outer diameter of the core tube, and then registers the unwinding progress of the membrane roll according to the unwound length. The unwound length is based on the cumulative unwound length of the membrane material before the inspection section is led out. It is updated synchronously every time the inspection section is reselected during the inspection process to avoid different inspection sections within the same roll diameter layer from being mixed into other layers.

[0035] The roll diameter layer is formed according to a fixed layer division rule within the same detection task. The layer division rule is written into the configuration record before detection and is not changed during the detection process. If it is necessary to change the layer division rule, the current detection task is terminated, a new detection task and a new layer configuration version are re-established, and the original detection record is not merged into the valid detection record under the new configuration version.

[0036] Specifically, the unwinding section near the initial outer diameter of the membrane roll is registered as the outer layer detection position, the position where the outer diameter of the membrane roll gradually decreases from the initial outer diameter and enters the middle unwinding section is registered as the middle layer detection position, and the position near the outer diameter of the core tube but not yet within the influence range of the core tube fixing tape, end tape and core tube indentation is registered as the inner layer detection position.

[0037] When using the unwound length as an auxiliary registration method, the outer detection layer corresponds to the first section of the membrane roll after it begins to unwound, the middle detection layer corresponds to the middle section of the unwound length of the membrane roll, and the inner detection layer corresponds to the position near the end of the membrane roll but retaining the complete detection length.

[0038] The roll diameter layer must not be selected in the joint, splicing tape, obvious crease, contamination, edge damage, core tube fixing tape affected area, and end face crushed area; when the above areas are encountered during the test, the area shall be registered as an avoidance area, and a new test section shall be selected in the adjacent unaffected membrane section.

[0039] When registering the avoidance area, the reason for avoidance, the start and end positions of the avoidance, the corresponding roll diameter layer, and the location of the reselected inspection segment should be recorded. Subsequent inspection records must not use the marked positions within the avoidance area as valid reading positions. At least one inspection segment should be selected for each roll diameter layer. For high-precision film materials, film materials with historical batches showing abnormal tensile recovery, and film materials that require subsequent overprinting, bonding, and coating positioning, two inspection segments should be selected for each roll diameter layer.

[0040] A gap of at least one effective detection area length is maintained between two detection sections to avoid repeated stretching of the same local membrane segment, which could affect the results of subsequent tests. The detection section is formed sequentially along the length of the membrane material by a front clamping area, an effective detection area, and a rear clamping area. The front and rear clamping areas are only used to fix the membrane material, while the effective detection area is used to set the width detection position and detection marks later.

[0041] The effective detection zone length is fixed within the same detection task. For ordinary packaging films, it is 800 mm to 1200 mm; for protective films, composite films, and coated films, it is 1000 mm to 1800 mm; and for films that are prone to delayed recovery, it is 1200 mm to 2000 mm.

[0042] The lengths of the front and rear clamping areas are not included in the effective detection area length, and local deformation caused by clamping in the clamping area is not recorded as part of the film tensile properties. After the detection segment is selected, the detection segment number, corresponding roll diameter layer, lead-out direction, detection segment start position, detection segment end position, avoidance area number, and layer configuration version are registered so that subsequent width marking, leveling load, multi-level detection load, and effective detection records can all be traced back to the same detection segment.

[0043] The test segment number is formed by combining the membrane roll number, roll diameter layer number, and test segment sequence number. It cannot be reused within the same test task. If a test segment is determined to be invalid, its number is retained and the reason for invalidity is recorded. A new test segment number is used for newly selected test segments to avoid confusion between subsequent retest records and original test segment records.

[0044] S2, extend and fix the front and rear clamping areas of the detection section, set the width detection positions according to the effective width of the film material, and set detection marks at each width detection position. The specific implementation is as follows:

[0045] The detection segment selected in step S1 is smoothly drawn out from the membrane roll to be tested. During the drawing process, the front and back sides of the membrane material are kept consistent with the basic information record to avoid flipping the membrane for testing.

[0046] When unwinding the membrane material, it should be done in the normal unwinding direction of the membrane roll, and should not be pulled in the opposite direction. When the membrane material enters the testing station from the end face of the membrane roll via the support position, both sides of the membrane material should move forward synchronously to avoid pulling one side first and causing oblique pre-tension. The front end of the testing section enters the front clamping area, and the rear end of the testing section enters the rear clamping area. The clamping boundaries of both the front and rear clamping areas are arranged along the width direction of the membrane material, and the clamping boundaries are kept parallel to the testing reference.

[0047] Before clamping, clean the clamping surface. The clamping surface must be free of hard particles, tape residue, and localized protrusions to avoid creating localized indentations during clamping. The clamping width of the front and rear clamping areas should be 30 mm to 80 mm; for thin film materials, 30 mm to 50 mm; and for thicker film materials and composite films, 50 mm to 80 mm. The clamping area must not overlap with the effective detection area, and detection marks must not be placed within the clamping area.

[0048] After clamping is completed, read the clamping boundary positions of the front clamping area and the rear clamping area, and register the relative position between the clamping boundary and the detection reference. If the clamping boundaries of the front clamping area and the rear clamping area are not parallel, re-clamp and then set the width detection position.

[0049] After clamping, set the width detection positions according to the effective width of the membrane material. When the effective width of the membrane material is less than 300 mm, set three width detection positions: left side, middle side, and right side. When the effective width of the membrane material is between 300 mm and 1200 mm, set five width detection positions: left side, left-middle side, middle side, right-middle side, and right side. When the effective width of the membrane material is greater than 1200 mm, set seven width detection positions.

[0050] Both the left and right strips should avoid rough edges, heat-sealed edges, cut waste edges, and obviously curled edges, and should be at least 20 mm away from the effective boundary; when the edge curls obviously, the edge coating is thick, or there is a risk of indentation on the edge, the distance from the effective boundary should be 40 mm to 80 mm.

[0051] The central band is located in the center of the effective width of the membrane material, while the left and right central bands are located between the corresponding side bands and the central band, respectively. The seven width-oriented detection positions are evenly distributed according to the effective width, but each detection position avoids joints, contamination, and obvious creases. Once a width-oriented detection position is formed, its distance from the left effective boundary is recorded and remains unchanged during loading, holding, and rereading within the same detection segment.

[0052] Detection marks are set at each width-direction detection position. The detection marks are set with front and rear marking points along the length of the film material, and a marking reference distance is formed between the front and rear marking points. The front marking point is close to the front clamping area but is kept at a distance from it, and the rear marking point is close to the rear clamping area but is kept at a distance from it. Both the front and rear marking points are located within the effective detection area.

[0053] The marking reference distance is fixed within the same testing task, ranging from 300 mm to 600 mm for ordinary membrane materials, and from 600 mm to 1000 mm for membrane materials with larger width, greater thickness, or significant delayed recovery. The testing marks are formed in a manner that does not affect the surface condition of the membrane material and can be stably identified by image reading, scale reading, or displacement reading devices; the testing marks must not cover wrinkles, curled edges, joints, contamination, or locations with significant thickness abrupt changes.

[0054] After the detection marks are formed, the initial mark position before the leveling load is applied is read first, and the mark reference distance between the front mark point and the rear mark point is checked to see if it is consistent with the configuration record. If the mark reference distance exceeds the allowable error of the configuration record, the detection marks are re-formed.

[0055] Each detection mark is registered with the width-direction detection position number, the initial position of the front mark point, the initial position of the rear mark point, the mark reference distance, the mark formation time, and the detection segment number. The detection reference is fixed before detection, and the positional relationship between the detection reference and the front clamping area, the rear clamping area, and the effective detection area is registered in the initial record. If the detection reference moves during the detection process, the current detection segment record is invalidated, and the width-direction detection position and detection mark settings are re-executed.

[0056] The determination of detection reference movement is based on the change in the position of the detection reference relative to the clamping boundary; when the change in the position of the detection reference reaches three times the resolution of the reading tool, it is registered as detection reference movement. After completing the setting of the width-direction detection position and detection mark, a mark configuration record is formed. The mark configuration record is bound to the detection segment number in step S1 and is used for the corresponding reading of subsequent initial stable records, multi-level detection load records and valid detection records.

[0057] S3, apply a leveling load to the detection section, and sequentially verify the film surface flatness, clamping condition, unwinding resistance, and detection mark status. The specific implementation is as follows:

[0058] A leveling load is applied to the detection section after clamping and marking are completed, and the film surface flatness, clamping state, unwinding resistance state, and detection mark state are verified before the formal multi-level detection load is applied. The leveling load is only used to release the initial relaxation of the detection section and form a readable flat state, and is not used as a load for judging tensile characteristics.

[0059] The leveling load should be 10% to 30% of the rated operating tension for subsequent processing; 15% to 25% for ordinary packaging films; 10% to 20% for thin, easily stretchable film materials; and 20% to 30% for composite and protective films. The leveling load should be applied gradually along the length of the film material, avoiding impact-type instantaneous loading. After applying the leveling load, maintain it for 5 to 30 seconds, during which time the detection mark positions at each width detection location should be read.

[0060] When the change in the position of the detection marker in two consecutive readings is less than the pre-registered initial stability threshold of 0.05 mm to 0.30 mm, the flat state of the membrane surface is registered as passed.

[0061] The initial stabilization threshold is registered when the detection task is established based on the reading tool resolution, film thickness, and subsequent processing accuracy requirements, and remains fixed within the same detection task. If the detection mark position continues to move unidirectionally, the leveling load is maintained; if it still does not stabilize after the preset holding time, it is registered as initial relaxation not released, and the detection segment is re-extracted.

[0062] When re-leading out the detection section, first release the current clamping, then continue to release membrane material from the membrane roll for at least the length of the front clamping area, so that the area originally affected by the leveling load is removed from the effective detection area, and then repeat step S2. During the clamping status verification, check whether there is oblique pressure, insufficient local clamping, non-parallel clamping boundaries, or slippage of the clamping area in the front and rear clamping areas.

[0063] During the leveling load holding period, if all width-direction detection positions move in the same direction, but the reference distance between the front and rear marker points does not change accordingly, it is determined that the clamping area has slipped as a whole. After re-clamping, the leveling load verification is performed again. If only one side strip shows significant movement, and this movement is accompanied by a local offset of the clamping boundary, it is recorded as insufficient local clamping and will not proceed to the multi-level detection load process. During the unwinding resistance status verification, the film roll support status, unwinding damping setting, end face contact status, and whether the film roll rotation is smooth are recorded.

[0064] During the leveling load maintenance period, if a sudden jump occurs at the detection mark position, and simultaneously there is membrane roll end-face friction, unwinding jamming, membrane roll jumping, or a change in damping setting, it is recorded as unwinding fluctuation and will not proceed to the formal inspection. After registering the unwinding fluctuation, check the contact state between the membrane roll end-face and the support, adjust the unwinding damping to the setting registered in the inspection task, and then re-pull the adjacent membrane segment.

[0065] During the verification of the detection marker status, each detection marker is confirmed to be clear, not detached, and not covered in folds or contaminated areas, and both the previous and subsequent marker points can be read stably. If the detection marker at a certain width-direction detection position cannot be read stably, the detection marker is re-formed; if it cannot be re-formed, the current detection segment is not considered a valid detection segment.

[0066] The inspection mark status verification also records whether the mark is warped, has reflective skipping, blurred edges, or is obstructed by clamped components; if any of the above conditions affect continuous reading, the corresponding width-direction inspection position is recorded as failing the mark status. After the film surface flatness status, clamping status, unwinding resistance status, and inspection mark status are all passed, an initial stability record is generated. The initial stability record includes the inspection segment number, roll diameter layer number, leveling load value, leveling holding time, initial readings of each width-direction inspection position, clamping status conclusion, unwinding resistance status conclusion, inspection mark status conclusion, and configuration version.

[0067] Only detection segments with initial stable records can proceed to subsequent multi-level detection load processes. After the initial stable record is formed, all subsequent multi-level detection load readings use the initial reading in this record as the reading reference for the same detection segment; if the initial stable record is missing, the configuration version is inconsistent, or the detection segment number is inconsistent, subsequent readings cannot be registered as valid detection records.

[0068] S4, apply multiple levels of detection load sequentially to the detection section along the length of the membrane material. After each level of detection load is in place and maintained, read the detection mark position of each width-direction detection position. Then unload and read the restored detection mark position. The specific implementation is as follows:

[0069] After the initial stable record is formed, multiple levels of detection load are sequentially applied to the detection section along the length of the membrane material. The multiple levels of detection load are executed in ascending order, and the highest detection load cannot be directly applied from the leveling load. The multiple levels of detection load consist of a first-level detection load, a second-level detection load, and a third-level detection load.

[0070] The first-level testing load is 40% to 60% of the rated operating tension of subsequent processing; the second-level testing load is 70% to 90% of the rated operating tension of subsequent processing; and the third-level testing load is 100% to 120% of the rated operating tension of subsequent processing. When the membrane material supply information gives the maximum allowable tension, the third-level testing load is less than 80% of the maximum allowable tension.

[0071] When the third-level test load of thin, easily stretchable film materials and heat-sealable film materials is lower than the rated operating tension for subsequent processing, the reason for the load reduction, the third-level test load value after the load reduction, and the corresponding configuration version should be recorded in the test record. During the application of each level of test load, the loading direction should be consistent with the length direction of the film material, and the loading point should be coaxially aligned with the front and rear clamping areas to avoid oblique stretching.

[0072] After each level of detection load reaches the set value, maintain the load stable for 2 to 5 seconds, then read the detection mark position of each width detection position to form the load reading; continue to maintain for 10 to 30 seconds, then read the detection mark position of each width detection position to form the holding reading.

[0073] Both loaded and held readings are recorded separately for each width-direction detection position. The full-width average reading is not used to replace the actual readings for the side strips, center strips, and other width-direction positions. Each level of detection load is read at least twice. If the difference between consecutive readings is less than the holding stability threshold, the reading for that level of detection load is recorded as valid. If the reading continues to change during the longest holding time, it is recorded as a continuous deformation pending verification and is not directly used as the final abnormal conclusion.

[0074] A stable threshold is written into the configuration record at the start of the inspection task: 0.05 mm to 0.30 mm for ordinary packaging films, and 0.03 mm to 0.15 mm for precision bonding films and optical protective films. After the first-level inspection load is completed, the second-level inspection load begins, and after the second-level inspection load is completed, the third-level inspection load begins. If any tearing of the film material, slippage of the clamping area, detachment of the inspection mark, unwinding jamming, or movement of the inspection reference occurs at any stage of the load, the effective reading of the current inspection segment is stopped, the cause of the anomaly is recorded, and a new inspection segment is selected.

[0075] When registering the cause of an anomaly, the load level, time of occurrence, corresponding width-direction detection location, and handling method should be recorded. Subsequent retest records should be linked to this anomaly record. After the three-level detection load reading is completed, the load should be unloaded according to the fixed unloading rules in the same detection task. For ordinary packaging films, the detection load should be unloaded to the leveling load and then allowed to recover. For composite films, protective films, and films with obvious delayed recovery, the load should be unloaded step by step in the order of three-level detection load, two-level detection load, one-level detection load, and leveling load.

[0076] During step-by-step unloading, hold for 2 to 5 seconds after each unloading stage to avoid bouncing back readings during the unloading process; after unloading to the leveled load, hold for 10 to 120 seconds, 30 to 60 seconds for ordinary membrane materials and 60 to 120 seconds for delayed recovery membrane materials; after the recovery time is over, read the detection mark position of each width detection position and register it as the detection mark position after recovery.

[0077] For membrane materials with high alignment requirements, the detection mark position is read twice after recovery: the first time 30 seconds after unloading, and the second time 60 seconds after unloading. If the difference between the two readings exceeds the recovery stabilization threshold, it is registered as an unstable recovery state and enters the retest process. The recovery stabilization threshold is bound to the detection task configuration version, and the same recovery time and reading interval are used during retesting.

[0078] The records of the entire multi-level detection load process correspond to the detection segment number, roll diameter layer number, width detection position number, and detection mark number, avoiding the mixing of records between different layers, different width positions, and different detection loads. The original readings are retained for loading readings, holding readings, and the detection mark position after recovery; no manually corrected values ​​are used to replace the original readings. If abnormal readings occur, they are eliminated and verified through step S5.

[0079] S5, exclude detection records corresponding to clamping slippage, clamping twisting, unwinding fluctuation, and marking anomalies, and register valid detection records according to roll diameter layer and width direction detection position. The specific implementation is as follows:

[0080] After the multi-level detection load and the recovered detection mark position are read, the detection records of the current detection segment are excluded and verified, and valid detection records are registered according to the roll diameter layer and the width detection position.

[0081] Before excluding verification, the initial stable record is read first, and then clamping slippage, clamping torsion, unwinding fluctuation, and marking anomalies are verified in sequence. During clamping slippage verification, the positional changes of the front and rear clamping areas before and after the detection are checked. If there is visible movement in the clamping area, or if each width-direction detection position moves in the same direction as a whole at the same time and the marking reference distance does not change accordingly, the current detection segment is registered as a clamping slippage record and cannot be included in the valid detection record.

[0082] The clamping and sliding record retains the detection section number, the load setting, the change in the clamping area position, and the re-clamping process record to avoid mistaking the detection section for abnormal stretching of the membrane material itself in the future.

[0083] During the clamping torsion verification, the changes in the position of the detection marks of the left strip, right strip, and middle strip under the leveling load and the first-level detection load are compared. If the detection position of the left width direction is offset in opposite directions from the detection position of the right width direction, and this offset has already occurred in the leveling load stage, the current detection segment is registered as clamping torsion to be retested.

[0084] After re-clamping adjacent test sections, if the same trend disappears, the original record is excluded as a clamping torsion. If the same trend recurs in the same roll diameter layer and the same width region after re-clamping, it is entered into the valid test record registration. During unwinding fluctuation verification, the time sequence of film roll rotation, unwinding damping, end face friction, and sudden changes in the position of the test mark is checked. If the sudden change in the position of the test mark corresponds to unwinding jamming, end face runout, or change in damping setting, the reading of that section is registered as an unwinding fluctuation record and cannot be used as a valid test record.

[0085] The unwinding fluctuation record retains the readings before and after the abrupt change, but these readings are only used to explain the cause of exclusion and are not included in the valid record summary for roll diameter layer and width detection position. During the mark anomaly verification, if the detection mark is detached, obscured, folded, reflects light, skips readings, or its position cannot be stably read, the corresponding width detection position is registered as a mark anomaly; if the number of mark anomalies reaches more than one-third of the total number of width detection positions in the current detection segment, the current detection segment as a whole is registered as an invalid detection segment.

[0086] If the number of marked anomalies does not reach the above-mentioned proportion, only the readings of the corresponding width-direction detection positions are excluded. The remaining width-direction detection positions are included in the valid detection record after verification. After exclusion and verification, a valid detection record is formed according to the membrane roll number, roll diameter layer number, detection segment number, width-direction detection position number, detection load level, loaded reading, held reading, detection mark position after recovery, initial stable record number, exclusion verification conclusion, and record validity.

[0087] Valid test records are archived according to roll diameter and width direction test position. For the same roll, the outer layer test position, middle layer test position and inner layer test position are respectively retained as corresponding records. For the same test section, the left side strip, left-middle strip, middle strip, right-middle strip and right side strip are respectively retained as corresponding records.

[0088] If there is a pending retest status in the test record, steps S2 to S5 are repeated in the adjacent membrane segment that is not affected by joints, contamination, or edge damage. After the retest is passed, a correspondence is established between the initial record and the retest record. If the retest is inconsistent, it is registered as a record pending verification. If the retest is consistent, it is registered as a valid test record.

[0089] The rules for consistency in retests are as follows: the retest record and the first record show the same direction of change under the same roll diameter layer, the same width region, and the same test load level, and the change in the position of the restored test mark reaches the same pre-registered judgment caliber; when the retests are inconsistent, the first record will not be used as the sole basis for the abnormality of the membrane material.

[0090] Once a valid test record is created, the loaded reading, the retained reading, and the position of the restored test mark will no longer be modified. If errors are subsequently found in the configuration version, test baseline, or mark number, only a correction record can be added with an explanation of the reason; the original valid test record will not be overwritten.

[0091] The resulting valid test records serve as the basis for subsequent judgments on inconsistent width of the roll film material, excessive local residual elongation, and insufficient elastic recovery. Furthermore, each judgment criterion can be traced back to the corresponding roll number, roll diameter layer number, test section number, width test location number, and exclusion verification conclusion.

[0092] In one specific embodiment, the film roll to be tested is a packaging composite film roll with an effective width of 800 mm, a nominal thickness of 0.05 mm, an initial outer diameter of 600 mm, an outer diameter of 76 mm for the core tube, a total length of 3000 meters, a rated operating tension of 120 N for subsequent processing, and a maximum allowable tension of 180 N.

[0093] Before testing, establish basic information records for the same testing task and divide the membrane roll into outer layer, middle layer, and inner layer testing sections. One testing section is selected for each roll diameter section, avoiding joints, splicing tape, obvious creases, contamination, edge damage, areas affected by core tube fixing tape, and end-face pressure damage. The effective testing area length for each section is set to 1000 mm, and the clamping width of both the front and rear clamping areas is set to 50 mm.

[0094] After the detection segment corresponding to the outer detection layer is drawn out from the film roll to be tested, the front end of the detection segment enters the front clamping area and the rear end of the detection segment enters the rear clamping area. The clamping boundaries of the front clamping area and the rear clamping area are arranged along the width direction of the film material.

[0095] Five width-direction detection positions are set according to the effective width of the membrane material: left side, left-center, middle, right-center, and right side. The left and right side bands are each 50 mm away from their corresponding effective boundaries. The middle band is located at the center of the effective width of the membrane material. The left-center band is located between the left and middle bands, and the right-center band is located between the middle and right bands. Each width-direction detection position is marked with a front and a rear marker, with a marking reference distance of 500 mm between the front and rear markers.

[0096] Apply a leveling load of 24 N to the detection section and hold for 15 seconds. During the holding period, read the detection mark position of each width detection position twice consecutively. If the change in the detection mark position between two consecutive readings is less than 0.10 mm, and there is no slippage in the front and rear clamping areas, no end-face friction, unwinding jamming, or membrane roll jumping, and the detection marks are clear and have not fallen off, then an initial stable record is formed.

[0097] The initial stability record includes the detection segment number, outer layer detection position number, leveling load value, leveling holding time, initial readings of each width detection position, clamping status conclusion, unwinding resistance status conclusion, detection mark status conclusion, and configuration version.

[0098] After the initial stable record is formed, a first-level detection load, a second-level detection load, and a third-level detection load are sequentially applied to the detection section along the length of the membrane material. The first-level detection load is set to 60 N, the second-level detection load to 96 N, and the third-level detection load to 132 N. The third-level detection load is less than 80% of the maximum allowable tension.

[0099] After each level of detection load reaches the set value, it is held for 3 seconds, and then the detection mark position of each width detection position is read to form the load reading; it is held for another 20 seconds, and then the detection mark position of each width detection position is read to form the hold reading. After the three levels of detection load hold readings are completed, the detection load is unloaded to the leveling load and held under the leveling load for 60 seconds, and then the detection mark position of each width detection position after recovery is read.

[0100] In the detection section of the outer detection layer, the loading and holding readings of the right strip under the level 3 detection load are both greater than those of the middle strip. After unloading and holding for 60 seconds, the position of the detection mark after recovery of the right strip is still 0.85 mm away from the initial reading, the position of the middle strip is 0.20 mm away from the initial reading, and the position of the left strip is 0.38 mm away from the initial reading.

[0101] Subsequently, an exclusion verification was performed. No positional changes were observed in the front and rear clamping areas, and no unidirectional movement was observed in the detection positions across the width. No unwinding jamming, end-face runout, or damping setting changes occurred during the detection process. The detection mark on the right side remained intact, unobstructed, and read stably. Therefore, the corresponding record on the right side of this outer layer detection position was registered as a valid detection record.

[0102] Under the same testing task and configuration version, tests were performed on the middle layer and inner layer testing locations respectively. In the middle layer testing location, the five width-direction testing positions completed loading readings, holding readings, and readings of the testing mark positions after recovery under the first-level testing load, second-level testing load, and third-level testing load. After verification, no clamping slippage, clamping torsion, unwinding fluctuations, or marking abnormalities were found, and each width-direction testing location was registered as a valid testing record.

[0103] In the inner layer detection layer, the left, left-middle, and middle strips showed continuous changes during the secondary detection load holding phase. After unloading and holding for 60 seconds, the detection mark position after recovery was still higher than the pre-registered residual change judgment caliber in the same detection task. After excluding the absence of clamping slippage, clamping torsion, unwinding fluctuation, and mark abnormalities during verification, the corresponding width detection position of the inner layer detection layer was registered as a valid detection record and archived together with the valid detection records of the outer and middle layers detection layers.

[0104] The above specific embodiments are only used to illustrate the execution process of the method of the present invention in a packaging composite film roll inspection task. The effective width of the film material, the nominal thickness of the film material, the initial outer diameter of the film roll, the outer diameter of the core tube, the total length of the film roll, the length of the inspection section, the clamping width, the leveling load, the multi-level inspection load, the holding time, and the recovery time can all be registered within the range defined by the aforementioned specific embodiments according to the film material type and subsequent processing requirements. This does not change the inspection process of the present invention, which uses the roll diameter layer position, the width direction inspection position, the multi-level inspection load, the position of the inspection mark after recovery, and the exclusion of verification to form a valid inspection record.

[0105] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for testing the tensile properties of rolled film material, characterized in that, include: S1. Register the basic information of the membrane roll to be tested, divide the roll diameter into layers according to the initial outer diameter of the membrane roll, the outer diameter of the core tube and the unwound length, and select the test segment in each roll diameter layer. S2, extend the detection section and fix the front clamping area and the rear clamping area, set the width detection position according to the effective width of the film material, and set the detection mark at each width detection position; S3, apply a leveling load to the detection section, and check the film surface flatness, clamping status, unwinding resistance status and detection mark status in sequence; S4. Apply multiple levels of detection load to the detection section along the length of the membrane material. After each level of detection load is in place and maintained, read the detection mark position of each width detection position. Then unload and read the restored detection mark position. S5. Exclude the detection records corresponding to clamping slippage, clamping twisting, unwinding fluctuation and marking abnormalities, and register valid detection records according to roll diameter layer and width detection position.

2. The method for detecting the tensile properties of a roll film material according to claim 1, characterized in that: In S1, the basic information of the membrane roll to be tested is registered, including the membrane roll number, membrane material name, membrane material material, effective width of the membrane material, nominal thickness of the membrane material, initial outer diameter of the membrane roll, outer diameter of the core tube, total length of the membrane roll, winding direction, front and back directions of the membrane material, rated operating tension for subsequent processing, maximum allowable tension, and testing station number.

3. The method for detecting the tensile properties of a roll film material according to claim 1, characterized in that: In S1, the roll diameter layer is divided into outer layer inspection layer, middle layer inspection layer and inner layer inspection layer according to the initial outer diameter of the film roll, the outer diameter of the core tube and the unwound length. The inspection section avoids joints, splicing tape, obvious creases, contamination, edge damage, core tube fixing tape influence area and end face crush area.

4. The method for detecting the tensile properties of a roll film material according to claim 1, characterized in that: In S2, when the effective width of the membrane material is less than 300 mm, three width detection positions are set: left side, middle side and right side. When the effective width of the membrane material is between 300 mm and 1200 mm, five width detection positions are set: left side, left-middle side, middle side, right-middle side and right side. When the effective width of the membrane material is greater than 1200 mm, seven width detection positions are set.

5. The method for detecting the tensile properties of a roll film material according to claim 1, characterized in that: In S2, a front marker and a rear marker are set at each width detection position. A marking reference distance is formed between the front marker and the rear marker. The marking reference distance is 300 mm to 1000 mm and remains fixed within the same detection task.

6. The method for detecting the tensile properties of a roll film material according to claim 1, characterized in that: In S3, the leveling load is 10% to 30% of the rated operating tension of subsequent processing. The leveling load is maintained for 5 to 30 seconds. When the change in the position of the detection mark between two consecutive readings is less than the pre-registered initial stability threshold of 0.05 mm to 0.30 mm, the verification of the flatness of the membrane surface is completed.

7. The method for detecting the tensile properties of a roll film material according to claim 1, characterized in that: In S3, the clamping status verification reads the clamping boundary, clamping width, and position changes of the clamping area in the front and rear clamping areas; the unwinding resistance status verification reads the film roll support status, unwinding damping level, end face contact status, and film roll rotation status; and the detection mark status verification reads the detection mark clarity status, adhesion status, and position reading status.

8. The method for testing the tensile properties of a roll film according to claim 1, characterized in that: In S4, the multi-level detection load is in sequence as first-level detection load, second-level detection load and third-level detection load. The first-level detection load is 40% to 60% of the rated operating tension of the subsequent processing, the second-level detection load is 70% to 90% of the rated operating tension of the subsequent processing, and the third-level detection load is 100% to 120% of the rated operating tension of the subsequent processing. The third-level detection load is less than 80% of the maximum allowable tension.

9. The method for testing the tensile properties of a roll film according to claim 1, characterized in that: In S4, after each level of detection load reaches the set value, it is held for 2 to 5 seconds and the detection mark position after loading is read. It is held for another 10 to 30 seconds and the detection mark position after holding is read. After unloading to the leveling load, it is held for 10 to 120 seconds and the detection mark position after recovery is read.

10. The method for detecting the tensile properties of a roll film material according to claim 1, characterized in that: In S5, valid test records are registered according to the membrane roll number, roll diameter layer number, test segment number, width test position number, test load level, test mark position after loading, test mark position after holding, test mark position after recovery, initial stability record number, and exclusion verification conclusion.

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