Autonomous control method for the preparation process of long glass fiber reinforced plastics based on image vision

Abstract

The present invention relates to the technical field of composite materials, and in particular to an autonomous control method for the preparation process of long glass fiber reinforced plastics based on image vision, including judging the color difference interval of glass fiber and standard sample, judging whether there is floating fiber in the colloid according to the color difference interval; judging whether the floating fiber situation is at the first floating fiber level or the second floating fiber level according to the floating fiber ratio; when the first floating fiber level is reached, judging the cause of the floating fiber as insufficient and uneven impregnation according to the diameter difference between the material diameters; judging whether the equipment parameters are within a preset range and adjusting the equipment parameters; when the second floating fiber level is reached, judging the offset according to the diameter difference of the material; judging the offset degree as the first category or the second category according to the offset amount, analyzing the offset trend, and adjusting the ratio or traction strength of the polypropylene resin. The present invention judges the cause of the floating fiber and controls the preparation process accordingly by performing image view analysis on the colloid prepared by long glass fiber reinforced plastics.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to an autonomous control method for a long glass fiber reinforced plastic preparation process based on image vision. Background Art

[0002] In order to improve the strength and temperature resistance of products, using glass fiber to reinforce and modify plastics has always been a very good choice. A large number of facts have also proved the good performance brought by glass fiber. However, glass fiber and plastic are two different materials, which naturally leads to compatibility issues between the two. Glass fiber exposure (or floating fiber) is a direct manifestation of the compatibility problem between the two.

[0003] Chinese patent application publication number: CN108752743A discloses a long glass fiber reinforced polypropylene composite material and a preparation method thereof, comprising the following steps: firstly, polypropylene resin, PP-g-MAH, EMMA, EAA, polypropylene chain scission agent, antioxidant and lubricant are mixed, plasticized by a twin-screw extruder, and then sent to an impregnation head for melt blending with glass fiber, traction discharge, pelletization, and obtaining a long glass fiber reinforced polypropylene composite material. The long glass fiber reinforced polypropylene composite material and the preparation method thereof, which are not easy to disperse glass fiber flocs during stirring, effectively avoid the situation that the polypropylene-based molten carrier does not cover the glass fiber bundle poorly by adopting suitable polypropylene, glass fiber, PP-g-MAH, especially EMMA, EAA and relatively superior processing technology, and effectively reduce the dispersion of glass fiber bundles without affecting the physical properties and processing of the long glass fiber reinforced polypropylene composite material, and further avoid the formation of glass fiber flocs, which block the automatic feeding pipe or the unloading port; it can be seen that the long glass fiber reinforced polypropylene composite material and the preparation method thereof have the following problems:

[0004] Without testing and controlling the quality of the finished rubber pellets, that is, the long glass fiber reinforced polypropylene composite materials, the fiber distribution during the production process cannot be understood in real time, resulting in an uncontrollable production process. Summary of the invention

[0005] To this end, the present invention provides an autonomous control method for the preparation process of long glass fiber reinforced plastic based on image vision, so as to overcome the problem in the prior art that there is no detection and control of the quality of the finished rubber particles, that is, the finished product quality of the long glass fiber reinforced polypropylene composite material, and the fiber distribution in the production process cannot be understood in real time, resulting in an uncontrollable production process.

[0006] To achieve the above object, the present invention provides an autonomous control method for the preparation process of long glass fiber reinforced plastic based on image vision, comprising:

[0007] Step S1, selecting a number of colloidal particle samples according to the initial detection quantity, measuring the reflectance spectra of glass fiber powder and standard samples, and determining the color difference range of the color difference between the two;

[0008] Step S2, when the color difference value is in the first color difference range, detect the reflectivity difference between the surface of the colloid sample and the standard sample; when the color difference value is in the second color difference range, detect the color difference pattern on the surface of the colloid sample; determine whether there is glass fiber on the surface of the colloid sample, and whether there is floating fiber on the colloid sample;

[0009] Step S3, judging whether the existing floating fibers are at the first floating fiber level or the second floating fiber level according to the ratio of the number of floating fiber colloid particles to the initial detected number of floating fibers;

[0010] Step S4, when the floating fiber condition is at the first floating fiber level, judging based on the diameter difference between the material diameters that the cause of the floating fiber is insufficient and uneven impregnation of the glass fiber in the polypropylene resin;

[0011] Step S5, judging that the reason for insufficient and uneven impregnation is that the equipment parameters are not within the preset range according to the impregnation temperature, impregnation pressure and screw speed, and adjusting the impregnation temperature, impregnation pressure and screw speed;

[0012] Step S6, when the floating fiber condition is at the second floating fiber level, judging the offset of the glass fiber bundle and the polypropylene resin in the material according to the diameter difference between the material diameter and the standard diameter;

[0013] Step S7, judging whether the degree of the offset is the first category or the second category according to the offset amount between the glass fiber bundle and the polypropylene resin, analyzing the variation trend of the generated offset, and adjusting the proportion or initial traction of the polypropylene resin.

[0014] Furthermore, the reflectance spectra of the glass fiber powder and the standard sample were measured, and the actual color difference between the two was calculated.

[0015] If the actual color difference value is less than or equal to the reference color difference value, it is judged that the color difference value between the glass fiber and the standard sample is in the first color difference interval;

[0016] If the actual color difference value is greater than the reference color difference value, it is judged that the color difference value between the glass fiber and the standard sample is in the second color difference interval;

[0017] When the color difference value is in the first color difference range, the reflectance difference between the surface of the colloid sample and the standard sample is detected.

[0018] If the reflectivity difference is less than or equal to the difference evaluation value, it is judged that the color difference between the colloid sample and the standard sample is within the allowable error range between the colloid sample and the standard sample, and the color of the colloid sample is within the normal range;

[0019] If the reflectivity difference is greater than the difference evaluation value, it is judged that the color difference between the colloid sample and the standard sample exceeds the allowable range of the error value between the colloid sample and the standard sample, and the color of the colloid sample exceeds the normal range;

[0020] When the color difference value is in the second color difference interval, if there are color difference lines on the surface of the colloid particle sample, it is judged that the color of the colloid particle sample is beyond the normal range;

[0021] When the color of the colloid particle sample exceeds the normal range, it is judged that glass fibers exist on the surface of the colloid particle sample and floating fibers exist in the colloid particle sample.

[0022] Furthermore, the number of the rubber particle samples with floating fibers is detected, and the ratio of the number of floating fiber rubber particles to the initial detection number of floating fibers is calculated.

[0023] If the floating fiber ratio is less than or equal to the reference ratio, it is judged that the glass fiber bundle after the long glass fiber and the molten polypropylene resin are mixed and extruded in the long glass fiber impregnator has floating fiber, and the existing floating fiber situation is at the first floating fiber level;

[0024] If the floating fiber ratio is greater than the reference ratio, it is judged that the glass fiber bundle after the long glass fiber and the molten polypropylene resin are mixed and extruded in the long glass fiber impregnator has floating fiber, and the floating fiber situation existing in the preparation process of the long glass fiber reinforced plastic is at the second floating fiber level;

[0025] The reference ratio is a preset value set according to historical material data.

[0026] Furthermore, when the floating fiber condition is at the first floating fiber level, the material diameters of the plurality of materials after dipping, mixing and extruding are detected;

[0027] Calculating an average diameter of the plurality of materials according to the material diameters of the plurality of materials, calculating a diameter difference between the material diameters of the plurality of materials and the average diameter, and calculating an actual variance according to the diameter difference of the plurality of materials, the actual variance being equal to the sum of squares of the diameter differences divided by the total number of glass fiber bundles;

[0028] If the actual variance is greater than the standard variance, it is judged that the diameter difference between the material diameters is lower than the normal range, and the material diameter fluctuation of the mixed extruded material is large;

[0029] The standard deviation is a preset value set according to historical variance data of materials that have passed qualification inspection.

[0030] Furthermore, when the fluctuation of the material diameter is large, it is judged that the cause of the floating fiber is that the glass fiber is not fully and evenly impregnated in the polypropylene resin, and the impregnation conditions of the glass fiber and the polypropylene resin are tested.

[0031] Further, the process of detecting the impregnation condition includes,

[0032] Use temperature sensors and pressure sensors to detect the impregnation temperature and impregnation pressure in the impregnation chamber of the long glass fiber impregnation machine, and compare the impregnation temperature and impregnation pressure with the corresponding preset range.

[0033] If the impregnation temperature and the impregnation pressure are within the preset range, it is judged that the impregnation parameters of the long glass fiber impregnation machine are within the normal range;

[0034] If the impregnation temperature and the impregnation pressure are not within the preset range, it is determined that the reason why the glass fiber is not fully and uniformly impregnated in the polypropylene resin is that the impregnation parameters of the long glass fiber impregnation machine do not meet the preset values, and the impregnation temperature and the impregnation pressure are adjusted according to the preset range of the impregnation temperature and the impregnation pressure;

[0035] When the impregnation parameters of the long glass fiber impregnation machine are within the normal range, the screw speed of the twin-screw extruder is tested.

[0036] If the screw speed is not within the preset range, it is judged that the reason why the glass fiber is not fully and evenly impregnated in the polypropylene resin is that the equipment parameters of the double-screw extruder do not meet the preset requirements, and the screw speed of the double-screw extruder is adjusted according to the preset range of the screw speed;

[0037] If the screw speed is within a preset range, a dispersant and a lubricant are added during the impregnation of the glass fiber with the polypropylene resin.

[0038] Furthermore, when the floating fiber condition is at the second floating fiber level, the diameter difference between the material diameter of the plurality of materials and the standard diameter is calculated.

[0039] If any diameter difference is greater than the difference evaluation value, and the material diameter is smaller than the standard diameter, it is judged that the diameter difference of several strips of material exceeds the normal range, and the diameter of several strips of material after dipping, mixing and extrusion is lower than the standard range;

[0040] When the diameters of several strips of material after impregnation, mixing and extrusion are lower than the standard range, it is determined that there is an offset between the glass fiber bundles and the polypropylene resin in the material, and the offset degree of the glass fiber bundles and the polypropylene resin in the mixed extrusion material is detected.

[0041] Further, the process of detecting the degree of deviation includes,

[0042] The images of glass fiber bundles and polypropylene resin in the mixed extruded material are obtained from several angles, and the boundaries between the glass fiber bundles and the molten resin are identified through image processing;

[0043] The offset of the boundary between the glass fiber bundle and the molten resin is calculated, a curve of the offset variation is drawn according to the offset, and a derivative function of the variation curve is obtained.

[0044] If the offset of the offset variation curve corresponding to any time point is greater than the critical error, it is judged that the offset degree between the glass fiber bundle and the polypropylene resin is the first category;

[0045] If the offset of the offset variation curve corresponding to any time point is less than or equal to the critical error, it is judged that the offset degree between the glass fiber bundle and the polypropylene resin is the second category;

[0046] The critical error is half of the allowable offset error value between the glass fiber bundle and the polypropylene resin in the material.

[0047] Further, when the degree of deviation between the glass fiber bundle and the polypropylene resin is the first category, the production is stopped;

[0048] When the degree of deviation between the glass fiber bundle and the polypropylene resin is the second category, the variation trend of the deviation is analyzed.

[0049] If the derivative function value of the offset change curve corresponding to any time point is greater than zero, it is judged that the offset generated by the material during the conveying process is increasing, and the ratio of the low-viscosity polypropylene resin to the high-crystalline polypropylene resin in the polypropylene resin is reduced;

[0050] If the derivative value of the offset change curve corresponding to any time point is equal to zero, it is determined that the offset of the material during the conveying process remains unchanged, and the initial traction force of the traction device on the material is reduced according to the offset of the glass fiber bundle and the polypropylene resin.

[0051] The present invention provides a method for preparing a long glass fiber reinforced plastic, comprising:

[0052] Step Z1, mixing polypropylene resin and additives in a certain proportion;

[0053] Step Z2, sending the mixed polypropylene resin into a twin-screw extruder for melt plasticization;

[0054] Step Z3, the long glass fiber is pulled out from the automatic control untwisting device and sent to the fiber pretreatment device for treatment;

[0055] Step Z4, the pretreated long glass fibers are mixed and extruded with molten polypropylene resin in a long glass fiber impregnator;

[0056] Step Z5, the mixed material is cooled in a cooling water tank and pulled by a pulling device with an initial pulling force, and then processed and formed by a blow dryer;

[0057] Step Z6: the formed material is then drawn into a pelletizer and cut into pellets.

[0058] Compared with the prior art, the beneficial effect of the present invention is that in the production process of long glass fiber reinforced plastics, the situation where the glass fibers are not fully impregnated or evenly distributed in the composite material, but float on the surface or local area of ​​the composite material is called floating fiber. When the floating fiber situation occurs, the surface of the composite material will have a color difference compared with the normal situation because the glass fibers float on the surface or local area of ​​the composite material. The present invention selects the produced colloid particles as samples, detects the color difference values ​​of the colloid particle samples and the standard samples, and determines the colloid particle samples whose color difference values ​​exceed the normal range as floating fiber colloid particles, and determines the severity of the floating fiber situation according to the ratio of the number of floating fiber colloid particles to the initial detection number of floating fibers; the quality of the colloid particles reflects the problems in the production process, and the problems in the production process are discovered and solved in time, avoiding the waste of human resources and the inaccuracy of manual detection of colloid particles, thereby improving the accuracy and stability of quality detection.

[0059] Furthermore, temperature and pressure are key factors affecting the resin fluidity and glass fiber wettability during the impregnation process. The present invention compares the impregnation temperature and the impregnation pressure with the corresponding preset intervals to determine whether the impregnation parameters of the long glass fiber impregnation machine are within a normal range, thereby improving the accuracy of detecting the impregnation link during the preparation of long glass fiber reinforced plastics.

[0060] Furthermore, the twin-screw extruder outputs molten polypropylene resin, and the working condition of the twin-screw extruder determines the melting condition of the polypropylene resin. Therefore, the impregnation condition of the glass fiber and the polypropylene resin is not only affected by the long glass fiber impregnation machine, but also by the working condition of the twin-screw extruder. The present invention judges the working condition of the twin-screw extruder by the screw speed, thereby improving the accuracy of detecting the melting and plasticizing link in the preparation process of the long glass fiber reinforced plastic.

[0061] Furthermore, adding additives such as dispersants and lubricants can increase the compatibility of glass fiber and resin, improve the uniformity of the dispersed phase, increase the interfacial bonding strength, reduce the separation of glass fiber and resin, and improve the exposure of glass fiber.

[0062] Furthermore, the present invention determines the cause of floating fibers according to the degree of floating fibers occurring during the production process. When the polypropylene resin and the glass fiber bundle are unevenly mixed, the diameter of the material is coarse and fine. Correspondingly, when there is an offset between the glass fiber bundle and the polypropylene resin, the diameter of the material changes together.

[0063] Furthermore, when the fluidity of the polypropylene resin is high, the combination of the polypropylene resin and the glass fiber bundle is not stable. After the material is extruded from the impregnation machine, the polypropylene resin is affected by external factors and deviates from the glass fiber bundle. During the preparation process, all glass fiber bundles will be affected, resulting in a large number of floating fibers in the produced pellets. By reducing the traction force of the traction device on the material, the deviation of the polypropylene resin on the glass fiber bundle is reduced, the proportion of floating fibers in the pellets is reduced, and the production efficiency is increased; low-viscosity polypropylene resin and high-crystalline polypropylene resin, the former improves the fluidity of the polypropylene resin, and the latter ensures the strength of the reinforced plastic, solving the contradiction between material fluidity and product strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic diagram of the process of autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision in an embodiment of the present invention;

[0065] Figure 2 Schematic diagram of the production of a method for preparing a long glass fiber reinforced plastic in an embodiment of the present invention;

[0066] Figure 3 Schematic diagram of the shape of the long glass fiber reinforced plastic prepared in an embodiment of the present invention;

[0067] Figure 4 This is a schematic diagram of a process for preparing a long glass fiber reinforced plastic according to an embodiment of the present invention;

[0068] In the figure: 1-glass fiber, 2-polypropylene resin, 3-material, 4-pellets, 5-twin screw extruder, 6-long glass fiber impregnation machine, 7-cooling water tank, 8-pelletizer, 9-screen. DETAILED DESCRIPTION

[0069] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0070] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0071] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0072] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] See also Figure 1-Figure 4 As shown, Figure 1 Schematic diagram of the process of autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision in an embodiment of the present invention; Figure 2 This is a production schematic diagram of a method for preparing a long glass fiber reinforced plastic according to an embodiment of the present invention; Figure 3 Schematic diagram of the shape of the long glass fiber reinforced plastic prepared in an embodiment of the present invention; Figure 4 Schematic diagram of the process of preparing long glass fiber reinforced plastic in an embodiment of the present invention.

[0074] The present invention provides an autonomous control method for a long glass fiber reinforced plastic preparation process based on image vision, comprising:

[0075] Step S1, selecting a number of colloidal particle samples according to the initial detection quantity, measuring the reflectance spectra of glass fiber powder and standard samples, and determining the color difference range of the color difference between the two;

[0076] Step S2, when the color difference value is in the first color difference range, detect the reflectivity difference between the surface of the colloid sample and the standard sample; when the color difference value is in the second color difference range, detect the color difference pattern on the surface of the colloid sample; determine whether there is glass fiber on the surface of the colloid sample, and whether there is floating fiber on the colloid sample;

[0077] Step S3, judging whether the existing floating fibers are at the first floating fiber level or the second floating fiber level according to the ratio of the number of floating fiber colloid particles to the initial detected number of floating fibers;

[0078] Step S4, when the floating fiber condition is at the first floating fiber level, judging based on the diameter difference between the material diameters that the cause of the floating fiber is insufficient and uneven impregnation of the glass fiber in the polypropylene resin;

[0079] Step S5, judging that the reason for insufficient and uneven impregnation is that the equipment parameters of the long glass fiber impregnation machine or the double-screw extruder rod are not within the preset range according to the impregnation temperature, impregnation pressure and screw speed, and adjusting the impregnation temperature, impregnation pressure and screw speed;

[0080] Step S6, when the floating fiber situation is at the second floating fiber level, judging whether there is an offset between the glass fiber bundle and the polypropylene resin in the material according to the diameter difference between the material diameter and the standard diameter;

[0081] Step S7, judging whether the degree of the offset is the first category or the second category according to the offset amount between the glass fiber bundle and the polypropylene resin, analyzing the variation trend of the generated offset, and adjusting the proportion or initial traction of the polypropylene resin.

[0082] The present invention provides a method for preparing a long glass fiber reinforced plastic, comprising:

[0083] Step Z1, mixing polypropylene resin and additives in a certain proportion;

[0084] Step Z2, sending the mixed polypropylene resin into a twin-screw extruder for melt plasticization;

[0085] Step Z3, the long glass fiber is pulled out from the automatic control untwisting device and sent to the fiber pretreatment device for treatment;

[0086] Step Z4, the pretreated long glass fibers are mixed and extruded with molten polypropylene resin in a long glass fiber impregnator;

[0087] Step Z5, the mixed material is cooled in a cooling water tank and pulled by a pulling device with an initial pulling force, and then processed and formed by a blow dryer;

[0088] Step Z6: the formed material is then drawn into a pelletizer and cut into pellets.

[0089] In this embodiment, the color of the long glass fiber reinforced plastic can be adjusted according to requirements, such as black, red and yellow.

[0090] Select a number of colloidal particle samples according to the initial test quantity;

[0091] Use a colorimeter to measure the reflectance spectra of glass fiber powder and standard sample, and calculate the actual color difference (ΔE value) between the two.

[0092] If the actual color difference value is less than or equal to the reference color difference value, it is judged that the color difference value between the glass fiber and the standard sample is in the first color difference interval;

[0093] If the actual color difference value is greater than the reference color difference value, it is judged that the color difference value between the glass fiber and the standard sample is in the second color difference interval;

[0094] The reference color difference value is a preset value set according to the reflection spectrum of the color.

[0095] When the color difference value is in the first color difference range, a spectrophotometer is used to detect the difference in reflectance between the surface of the colloid sample and the standard sample.

[0096] If the reflectivity difference is less than or equal to the difference evaluation value, it is judged that the color difference between the colloid sample and the standard sample is within the allowable error range between the colloid sample and the standard sample, and the color of the colloid sample is within the normal range;

[0097] If the reflectivity difference is greater than the difference evaluation value, it is judged that the color difference between the colloid sample and the standard sample exceeds the allowable range of the error value between the colloid sample and the standard sample, and the color of the colloid sample exceeds the normal range.

[0098] When the color difference value is in the second color difference interval, the colloid particle sample is irradiated with visible light to obtain a surface image of the colloid particle sample, and image analysis is performed on the surface image of the colloid particle sample.

[0099] If there are color difference lines on the surface of the colloid particle sample, it is judged that the color of the colloid particle sample is beyond the normal range.

[0100] Specifically, the first color difference interval is smaller than the second color difference interval, the glass fiber appears white in the dark resin, and the color difference lines are strip lines that appear when the glass fiber appears on the surface of the dark resin.

[0101] When the color of the colloid particle sample exceeds the normal range, it is judged that glass fibers exist on the surface of the colloid particle sample and floating fibers exist in the colloid particle sample.

[0102] The difference evaluation value is a preset value set according to the error value of the reflectivity difference between the colloid sample and the standard sample.

[0103] Test the number of plastic particle samples with floating fibers, and calculate the ratio of the number of floating fiber plastic particles to the initial number of floating fibers tested.

[0104] If the floating fiber ratio is less than or equal to the reference ratio, it is judged that the glass fiber bundle after the long glass fiber and the molten polypropylene resin are mixed and extruded in the long glass fiber impregnator has floating fiber, and the existing floating fiber situation is at the first floating fiber level;

[0105] If the floating fiber ratio is greater than the reference ratio, it is judged that the glass fiber bundle after the long glass fiber and the molten polypropylene resin are mixed and extruded in the long glass fiber impregnator has floating fiber, and the floating fiber situation existing in the preparation process of the long glass fiber reinforced plastic is at the second floating fiber level.

[0106] The reference ratio is a preset value set according to historical material data. In this embodiment, the reference ratio is 3%.

[0107] The first float degree is less than the second float degree.

[0108] In this embodiment, the total number of glass fiber bundles during the impregnation of the glass fiber bundles with the molten polypropylene resin is 17 bundles.

[0109] Specifically, in the production process of long glass fiber reinforced plastics, the situation in which the glass fibers are not fully impregnated or evenly distributed in the composite material, but float on the surface or local area of ​​the composite material is called floating fiber. When the floating fiber situation occurs, the surface of the composite material will have a color difference compared to normal conditions because the glass fibers float on the surface or local area of ​​the composite material. The present invention selects the produced colloid particles as samples, detects the color difference values ​​of the colloid particle samples and the standard samples, and determines the colloid particle samples whose color difference values ​​exceed the normal range as floating fiber colloid particles, and determines the severity of the floating fiber situation according to the ratio of the number of floating fiber colloid particles to the initial detection number of floating fibers; the quality of the colloid particles reflects the problems in the production process, and the problems in the production process are discovered and solved in time, avoiding the waste of human resources and the inaccuracy of manual detection of the colloid particles, thereby improving the accuracy and stability of quality detection.

[0110] When the floating fiber condition is at the first floating fiber level, an optical measuring instrument (such as a laser diameter measuring instrument, an image measuring instrument, etc.) is used to detect the material diameters of several strips of material after dipping, mixing and extrusion;

[0111] Calculate the average diameter of several strips of material according to their diameters, and calculate the diameter difference between the diameter of several strips of material and the average diameter.

[0112] The actual variance is calculated based on the diameter differences of several pieces of material. The actual variance is equal to the sum of the squares of the diameter differences divided by the total number of glass fiber bundles.

[0113] If the actual variance is less than or equal to the standard variance, it is judged that the diameter difference between the material diameters is within the normal range;

[0114] If the actual variance is greater than the standard variance, it is judged that the diameter difference between the material diameters is lower than the normal range, and the material diameter fluctuation of the mixed extruded material is large.

[0115] The standard deviation is a preset value set based on the historical variance data of materials that have passed the conformity inspection.

[0116] When the material diameter fluctuates greatly, it is judged that the reason for the floating fiber is that the glass fiber is not fully and evenly impregnated in the polypropylene resin. The impregnation of the glass fiber and the polypropylene resin is tested.

[0117] Use temperature sensors and pressure sensors to detect the impregnation temperature and impregnation pressure in the impregnation chamber of the long glass fiber impregnation machine, and compare the impregnation temperature and impregnation pressure with the corresponding preset range.

[0118] If the impregnation temperature and the impregnation pressure are within the preset range, it is judged that the impregnation parameters of the long glass fiber impregnation machine are within the normal range;

[0119] If the impregnation temperature and the impregnation pressure are not within the preset range, it is determined that the reason for the insufficient and uneven impregnation of the glass fiber in the polypropylene resin is that the impregnation parameters of the long glass fiber impregnation machine do not meet the preset values. The impregnation temperature and the impregnation pressure are adjusted according to the preset range of the impregnation temperature and the impregnation pressure.

[0120] Specifically, temperature is a key factor affecting the fluidity of resin and the wettability of glass fiber. Appropriate temperature can reduce the viscosity of resin, making it easier to flow and penetrate between the fibers of glass fiber. Too high temperature may cause resin decomposition or damage to glass fiber, thus affecting the performance of the final product. Too low temperature may cause poor resin fluidity and fail to fully impregnate glass fiber, affecting the bonding strength between glass fiber and resin.

[0121] Pressure is a key factor in promoting the flow of resin and ensuring that it fully impregnates the glass fiber. Appropriate pressure can promote the penetration of resin into the glass fiber and improve the bonding strength between the glass fiber and the resin. Too high pressure may cause damage to the glass fiber or excessive flow of resin, affecting the performance of the final product. Too low pressure may cause insufficient flow of resin, which cannot fully impregnate the glass fiber and affect the bonding strength between the glass fiber and the resin.

[0122] The present invention compares the impregnation temperature and the impregnation pressure with the corresponding preset intervals to determine whether the impregnation parameters of the long glass fiber impregnation machine are within a normal range, thereby improving the accuracy of detecting the impregnation link in the preparation process of the long glass fiber reinforced plastic.

[0123] When the impregnation parameters of the long glass fiber impregnation machine are within the normal range, the screw speed of the twin-screw extruder is tested.

[0124] If the screw speed is not within the preset range, it is judged that the reason why the glass fiber is not fully and evenly impregnated in the polypropylene resin is that the equipment parameters of the double-screw extruder do not meet the preset requirements, and the screw speed of the double-screw extruder is adjusted according to the preset range of the screw speed;

[0125] If the screw speed is within a preset range, a dispersant and a lubricant are added during the impregnation of the glass fiber with the polypropylene resin.

[0126] Specifically, the twin-screw extruder produces molten polypropylene resin, and the working condition of the twin-screw extruder determines the melting condition of the polypropylene resin. Therefore, the impregnation condition of the glass fiber and the polypropylene resin is not only affected by the long glass fiber impregnation machine, but also by the working condition of the twin-screw extruder. The present invention judges the working condition of the twin-screw extruder by the screw speed, thereby improving the accuracy of detecting the melting and plasticizing link in the preparation process of the long glass fiber reinforced plastic.

[0127] Adding additives such as dispersants and lubricants can increase the compatibility of glass fiber and resin, improve the uniformity of the dispersed phase, increase the interfacial bonding strength, reduce the separation of glass fiber and resin, and improve the exposure of glass fiber.

[0128] In this embodiment, the materials are mixed and extruded in the long glass fiber impregnator. Affected by the fiber outlet of the long glass fiber impregnator, the diameter of the materials will not be larger than the standard diameter.

[0129] When the floating fiber condition is at the second floating fiber level, calculate the diameter difference between the material diameter of several pieces of material and the standard diameter.

[0130] If any diameter difference is greater than the difference evaluation value, and the material diameter is smaller than the standard diameter, it is judged that the diameter difference of several strips of material exceeds the normal range, and the diameter of several strips of material after dipping, mixing and extrusion is lower than the standard range;

[0131] The standard diameter is a preset value set according to the fiber outlet of the long glass fiber impregnation machine.

[0132] When the diameters of several strips of material after impregnation, mixing and extrusion are lower than the standard range, it is judged that there is an offset between the glass fiber bundles and the polypropylene resin in the material.

[0133] Detect the degree of deviation of glass fiber bundles and polypropylene resin in the mixed extruded material.

[0134] An optical measuring instrument is used to obtain images of glass fiber bundles and polypropylene resin in the mixed extruded material from several angles, and the boundary between the glass fiber bundle and the molten resin is identified through image processing;

[0135] Calculate the offset of the boundary between the glass fiber bundle and the molten resin, where the offset is equal to the straight-line distance between the boundary between the glass fiber bundle and the molten resin, draw an offset variation curve according to the offset, and obtain a derivative function of the variation curve.

[0136] If the offset of the offset variation curve corresponding to any time point is greater than the critical error, it is judged that the offset degree between the glass fiber bundle and the polypropylene resin is the first category;

[0137] If the offset of the offset variation curve corresponding to any time point is less than or equal to the critical error, it is determined that the offset degree between the glass fiber bundle and the polypropylene resin is of the second category.

[0138] When the degree of deviation between the glass fiber bundle and the polypropylene resin is the first category, the production is stopped;

[0139] When the degree of deviation between the glass fiber bundle and the polypropylene resin is the second category, the variation trend of the deviation is analyzed.

[0140] If the derivative function value of the offset change curve corresponding to any time point is greater than zero, it is judged that the offset generated by the material during the conveying process is increasing, and the ratio of the low-viscosity polypropylene resin to the high-crystalline polypropylene resin in the polypropylene resin is reduced;

[0141] If the derivative value of the offset change curve corresponding to any time point is equal to zero, it is determined that the offset of the material during the conveying process remains unchanged, and the initial traction force of the traction device on the material is reduced according to the offset of the glass fiber bundle and the polypropylene resin.

[0142] The critical error is half of the allowable offset error value between the glass fiber bundle and the polypropylene resin in the material.

[0143] Specifically, the present invention determines the cause of floating fibers according to the degree of floating fibers occurring during the production process. When the polypropylene resin and the glass fiber bundle are unevenly mixed, the diameter of the material is coarse and fine. Correspondingly, when there is an offset between the glass fiber bundle and the polypropylene resin, the diameter of the material changes together.

[0144] When the fluidity of polypropylene resin is high, the combination of polypropylene resin and glass fiber bundle is not stable. After the material is extruded from the impregnation machine, the polypropylene resin is affected by external factors and deviates from the glass fiber bundle. During the preparation process, all glass fiber bundles will be affected, resulting in a large number of floating fibers in the produced pellets. By reducing the traction force of the traction device on the material, the deviation of the polypropylene resin on the glass fiber bundle is reduced, the proportion of floating fibers in the pellets is reduced, and the production efficiency is increased; low-viscosity polypropylene resin and high-crystalline polypropylene resin, the former improves the fluidity of the polypropylene resin, and the latter ensures the strength of the reinforced plastic, solving the contradiction between material fluidity and product strength.

[0145] In this embodiment, the glass fiber is used in the preparation of reinforced plastic in the form of glass fiber bundles, the polypropylene resin refers to the molten material attached to the glass fiber bundles, and the material refers to the product extruded after the glass fiber bundles are mixed and impregnated with the polypropylene resin.

[0146] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0147] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An autonomous control method for the preparation process of long glass fiber reinforced plastics based on image vision, characterized in that: include: Select a number of colloidal particle samples according to the initial test quantity, measure the reflectance spectra of glass fiber powder and standard samples, and determine the color difference range of the color difference between the two; When the color difference value is in the first color difference range, the reflectance difference between the surface of the colloid sample and the standard sample is detected; when the color difference value is in the second color difference range, the color difference pattern on the surface of the colloid sample is detected; it is determined whether there is glass fiber on the surface of the colloid sample, and whether there is floating fiber on the colloid sample; According to the ratio of the number of floating fiber particles to the number of floating fibers initially detected, it is judged whether the existing floating fibers are at the first floating fiber level or the second floating fiber level; When the floating fiber situation is at the first floating fiber level, it is judged based on the diameter difference between the material diameters that the reason for the floating fiber is that the glass fiber is not fully and evenly impregnated in the polypropylene resin; According to the impregnation temperature, impregnation pressure and screw speed, the reason for insufficient and uneven impregnation is that the equipment parameters are not within the preset range, and the impregnation temperature, impregnation pressure and screw speed are adjusted; When the floating fiber situation is at the second floating fiber level, the deviation of the glass fiber bundle and the polypropylene resin in the material is judged according to the diameter difference between the material diameter and the standard diameter; The degree of the offset is determined to be the first category or the second category according to the offset amount between the glass fiber bundle and the polypropylene resin, and the change trend of the generated offset is analyzed to adjust the proportion of the polypropylene resin or the initial traction force; Measure the reflectance spectra of glass fiber powder and standard sample, and calculate the actual color difference between the two. If the actual color difference value is less than or equal to the reference color difference value, it is judged that the color difference value between the glass fiber and the standard sample is in the first color difference interval; If the actual color difference value is greater than the reference color difference value, it is judged that the color difference value between the glass fiber and the standard sample is in the second color difference interval; When the color difference value is in the first color difference range, the reflectance difference between the surface of the colloid sample and the standard sample is detected. If the reflectivity difference is less than or equal to the difference evaluation value, it is judged that the color difference between the colloid sample and the standard sample is within the allowable error range between the colloid sample and the standard sample, and the color of the colloid sample is within the normal range; If the reflectivity difference is greater than the difference evaluation value, it is judged that the color difference between the colloid sample and the standard sample exceeds the allowable range of the error value between the colloid sample and the standard sample, and the color of the colloid sample exceeds the normal range; When the color difference value is in the second color difference interval, if there are color difference lines on the surface of the colloid particle sample, it is judged that the color of the colloid particle sample is beyond the normal range; When the color of the colloid sample exceeds the normal range, it is judged that glass fibers exist on the surface of the colloid sample and floating fibers exist in the colloid sample; Test the number of plastic particle samples with floating fibers, and calculate the ratio of the number of floating fiber plastic particles to the initial number of floating fibers tested. If the floating fiber ratio is less than or equal to the reference ratio, it is judged that the glass fiber bundle after the long glass fiber and the molten polypropylene resin are mixed and extruded in the long glass fiber impregnator has floating fiber, and the existing floating fiber situation is at the first floating fiber level; If the floating fiber ratio is greater than the reference ratio, it is judged that the glass fiber bundle after the long glass fiber and the molten polypropylene resin are mixed and extruded in the long glass fiber impregnator has floating fiber, and the floating fiber situation existing in the preparation process of the long glass fiber reinforced plastic is at the second floating fiber level; The reference ratio is a preset value set according to historical material data.

2. The method for autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision according to claim 1, characterized in that: When the floating fiber condition is at the first floating fiber level, the diameters of several strips of material after dipping, mixing and extrusion are tested; Calculating an average diameter of the plurality of materials according to the material diameters of the plurality of materials, calculating a diameter difference between the material diameters of the plurality of materials and the average diameter, and calculating an actual variance according to the diameter difference of the plurality of materials, the actual variance being equal to the sum of squares of the diameter differences divided by the total number of glass fiber bundles; If the actual variance is greater than the standard variance, it is judged that the diameter difference between the material diameters is lower than the normal range, and the material diameter fluctuation of the mixed extruded material is large; The standard deviation is a preset value set according to historical variance data of materials that have passed qualification inspection.

3. The method for autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision according to claim 2, characterized in that: When the material diameter fluctuates greatly, it is judged that the cause of floating fiber is insufficient and uneven impregnation of glass fiber in polypropylene resin, and the impregnation conditions of glass fiber and polypropylene resin are tested.

4. The method for autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision according to claim 3, characterized in that: The process of testing for impregnation includes: Use temperature sensors and pressure sensors to detect the impregnation temperature and impregnation pressure in the impregnation chamber of the long glass fiber impregnation machine, and compare the impregnation temperature and impregnation pressure with the corresponding preset range. If the impregnation temperature and the impregnation pressure are within the preset range, it is judged that the impregnation parameters of the long glass fiber impregnation machine are within the normal range; If the impregnation temperature and the impregnation pressure are not within the preset range, it is determined that the reason why the glass fiber is not fully and uniformly impregnated in the polypropylene resin is that the impregnation parameters of the long glass fiber impregnation machine do not meet the preset values, and the impregnation temperature and the impregnation pressure are adjusted according to the preset range of the impregnation temperature and the impregnation pressure; When the impregnation parameters of the long glass fiber impregnation machine are within the normal range, the screw speed of the twin-screw extruder is tested. If the screw speed is not within the preset range, it is judged that the reason why the glass fiber is not fully and evenly impregnated in the polypropylene resin is that the equipment parameters of the double-screw extruder do not meet the preset requirements, and the screw speed of the double-screw extruder is adjusted according to the preset range of the screw speed; If the screw speed is within a preset range, a dispersant and a lubricant are added during the impregnation of the glass fiber with the polypropylene resin.

5. The method for autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision according to claim 1, characterized in that: When the floating fiber condition is at the second floating fiber level, calculate the diameter difference between the material diameter of several pieces of material and the standard diameter. If any diameter difference is greater than the difference evaluation value, and the material diameter is smaller than the standard diameter, it is judged that the diameter difference of several strips of material exceeds the normal range, and the diameter of several strips of material after dipping, mixing and extrusion is lower than the standard range; When the diameters of several strips of material after impregnation, mixing and extrusion are lower than the standard range, it is determined that there is an offset between the glass fiber bundles and the polypropylene resin in the material, and the offset degree of the glass fiber bundles and the polypropylene resin in the mixed extrusion material is detected.

6. The method for autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision according to claim 5, characterized in that: The process of detecting the degree of deviation includes, The images of glass fiber bundles and polypropylene resin in the mixed extruded material are obtained from several angles, and the boundaries between the glass fiber bundles and the molten resin are identified through image processing; The offset of the boundary between the glass fiber bundle and the molten resin is calculated, a curve of the offset variation is drawn according to the offset, and a derivative function of the variation curve is obtained. If the offset of the offset variation curve corresponding to any time point is greater than the critical error, it is judged that the offset degree between the glass fiber bundle and the polypropylene resin is the first category; If the offset of the offset variation curve corresponding to any time point is less than or equal to the critical error, it is judged that the offset degree between the glass fiber bundle and the polypropylene resin is the second category; The critical error is half of the allowable offset error value between the glass fiber bundle and the polypropylene resin in the material.

7. The method for autonomously controlling the long glass fiber reinforced plastic preparation process based on image vision according to claim 6, characterized in that: When the degree of deviation between the glass fiber bundle and the polypropylene resin is the first category, the production is stopped; When the degree of deviation between the glass fiber bundle and the polypropylene resin is the second category, the variation trend of the deviation is analyzed. If the derivative function value of the offset change curve corresponding to any time point is greater than zero, it is judged that the offset generated by the material during the conveying process is increasing, and the ratio of the low-viscosity polypropylene resin to the high-crystalline polypropylene resin in the polypropylene resin is reduced; If the derivative value of the offset change curve corresponding to any time point is equal to zero, it is judged that the offset generated by the material during the conveying process remains unchanged, and the initial traction force of the traction device on the material is reduced according to the offset of the glass fiber bundle and the polypropylene resin.

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