A method and system for detecting quality of tobacco strands

Abstract

The present invention discloses a method and system for detecting the quality of a tobacco tow, which comprises: obtaining the density of each unit segment of the tow to be detected; calculating the number of joints of the tow to be detected according to the density of each unit segment; calculating the process capability index of the tow density according to the density of each unit segment; and judging the quality of the tow to be detected according to the process capability index of the tow density and the number of joints. The method for detecting the quality of tobacco tow can collect online production data of tow density and joints, and perform statistics and analysis on the above data to achieve real-time supervision of the quality of the tow, thereby improving the quality stability of the tow and enhancing the control level of the production process.

Description

Technical Field

[0001] The invention relates to the technical field of cigarette production, and in particular to a method and system for detecting the quality of cigarette strands. Background Art

[0002] Tobacco tow is the main raw material for processing tobacco filter rods. The stability and compliance of the tow line density have a great impact on the processing quality and production efficiency of the filter rods. Among them, the single-filament line density and the tow line density of the tow determine the standard pressure drop control range of the tobacco filter rod, and the stability of the tow line density has a great influence on the standard deviation of the filter rod suction resistance and weight. Therefore, in order to ensure the quality of the filter rod, before producing the filter rod, the tobacco filter rod processing company will select the tobacco tow raw materials of corresponding specifications according to the design requirements of the filter rod to be produced, and strictly control the quality of the tobacco tow raw materials.

[0003] At present, domestic cigarette filter rod processing enterprises mainly judge the quality of incoming tow raw materials through sampling testing. However, this testing method is limited by the number of samples and the testing method, and cannot comprehensively evaluate the quality of the tow, nor can it monitor the quality of the tow in real time. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the sampling detection method in the prior art cannot comprehensively evaluate the quality of the tow due to the limitations of the number of samples and the detection method, and cannot monitor the quality of the tow in real time. The present invention provides a method for detecting the quality of the tobacco tow, which collects the online production data of the tow density and the joint, and performs statistics and analysis on the above data to achieve real-time supervision of the tow quality, improve the quality stability of the tow, and enhance the control level of the production process.

[0005] Based on this, an embodiment of the present invention discloses a method for detecting the quality of a cigarette strand, comprising:

[0006] Obtaining the density of each unit segment on the tow to be detected;

[0007] Calculate the number of joints of the tow to be tested according to the tow density of each unit segment;

[0008] Calculate the tow density process capability index based on the tow density of each unit segment;

[0009] The quality of the yarn bundle to be tested is determined based on the yarn bundle density process capability index and the number of joints.

[0010] By adopting the above technical solution, online production data of tow density and joints are collected, and the above data are counted and analyzed to achieve real-time supervision of tow quality, improve the quality stability of the tow, and enhance the control level of the production process.

[0011] According to another specific embodiment of the present invention, calculating the number of joints of the tow to be detected according to the tow density of each unit segment includes:

[0012] The fiber bundle density of each unit segment is compared with a preset range respectively, and when the fiber bundle density of the unit segment is within the preset range, the unit segment is determined to be a joint position;

[0013] The number of joints is obtained by summing up the number of joint positions on the to-be-detected yarn bundle.

[0014] According to another specific embodiment of the present invention, a method for obtaining a preset range includes:

[0015] The standard tow and the tow with a joint are tested respectively to obtain the tow density of each unit segment on the standard tow and the tow density of each unit segment on the tow with a joint; wherein the standard tow is a tow without a joint and without a break;

[0016] Determine a tow density threshold value according to the tow density of each unit segment on the standard tow;

[0017] For the strand density of each unit segment on the strand with a joint, select each strand density greater than a strand density threshold;

[0018] Determine the preset range based on all the tow densities selected in the previous step.

[0019] According to another specific embodiment of the present invention, obtaining the density of each unit segment on the tow to be detected includes:

[0020] A microwave sensor and a speed sensor are respectively arranged upstream of the opener;

[0021] The speed sensor obtains the movement speed of the tow to be detected at regular intervals, and determines the detection time according to the preset length and the movement speed currently detected by the speed sensor. When the detection time is reached, the microwave sensor obtains the tow density of the tow unit segment located inside it, and records the tow density of the unit segment until the end of the tow to be detected enters the opener.

[0022] According to another specific embodiment of the present invention, it also includes: constructing a tow density database according to all the tow densities obtained by recording.

[0023] According to another specific embodiment of the present invention, when the to-be-detected silk bundle is a multi-package silk bundle, the cigarette silk bundle quality detection method further comprises:

[0024] The mean and standard deviation of the process capability index of the tow density and the mean and standard deviation of the number of joints corresponding to each bundle of tows are calculated respectively;

[0025] The quality of the yarn bundle to be tested is judged according to the mean and standard deviation of the yarn bundle density process capability index and the number of joints, respectively.

[0026] Accordingly, an embodiment of the present invention further discloses a tobacco strand quality detection system, comprising:

[0027] A density acquisition module is used to acquire the density of each unit segment on the tow to be detected;

[0028] A first calculation module, used for calculating the number of joints of the tow to be detected according to the tow density of each unit segment;

[0029] A second calculation module is used to calculate a tow density process capability index according to the tow density of each unit segment;

[0030] The judging module is used to receive the number of joints output by the first calculating module and the process capability index of the tow density output by the second calculating module, and judge the quality of the tow to be tested according to the process capability index of the tow density and the number of joints.

[0031] According to another specific embodiment of the present invention, the first calculation module includes:

[0032] A joint determination unit, used to compare the fiber bundle density of each unit segment with a preset range respectively, and when the fiber bundle density of the unit segment is within the preset range, the joint determination unit determines that the unit segment is a joint position;

[0033] The statistical unit is used to accumulate the number of all joint positions on the to-be-detected yarn bundle to obtain the number of joints.

[0034] According to another specific embodiment of the present invention, a method for obtaining a preset range includes:

[0035] The standard tow and the tow with a joint are tested respectively to obtain the tow density of each unit segment on the standard tow and the tow density of each unit segment on the tow with a joint; wherein the standard tow is a tow without a joint and without a break;

[0036] Determine a tow density threshold value according to the tow density of each unit segment on the standard tow;

[0037] For the strand density of each unit segment on the strand with a joint, select each strand density greater than a strand density threshold;

[0038] Determine the preset range based on all the tow densities selected in the previous step.

[0039] According to another specific embodiment of the present invention, the density acquisition module includes:

[0040] A speed sensor is arranged upstream of the opener, and detects the moving speed of the tow to be detected once at a certain interval;

[0041] A calculation unit, used to receive the motion speed currently output by the speed sensor, and determine the detection time according to the preset length and the current motion speed, and when the detection time is reached, the calculation unit sends a trigger signal;

[0042] A microwave sensor is arranged upstream of the opener, and is used to receive a trigger signal output by the calculation unit and be triggered to obtain the tow density of the tow unit segment located inside the microwave sensor;

[0043] The storage unit is used to record the tow density of the unit segment obtained by the microwave sensor and to build a tow density database according to all the recorded tow densities.

[0044] Correspondingly, an embodiment of the present invention further discloses a computer-readable storage medium, on which instructions are stored, and when the instructions are executed on a computer, the computer executes the above-mentioned method for detecting the quality of tobacco strands. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flow chart showing a method for detecting the quality of tobacco strands provided by a specific embodiment of the present invention;

[0046] Figure 2 A schematic diagram of data partitioning provided by a specific embodiment of the present invention is shown;

[0047] Figure 3 A structural block diagram of a tobacco strand quality detection system provided in a specific embodiment of the present invention is shown. DETAILED DESCRIPTION

[0048] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0049] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0050] In the description of this embodiment, it should be noted that the terms “first”, “second”, etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0052] like Figure 1 As shown, one embodiment of the present invention provides a method for detecting the quality of a cigarette strand, comprising:

[0053] Step S1: obtaining the density of each unit segment on the tow to be detected.

[0054] Generally, during the production process, the filament bundle needs to be loosened by an opener before entering the forming machine to form a filter rod. Optionally, a microwave resonance detector can be set upstream of the opener (based on the transmission direction of the filament bundle) to detect the density of the filament bundle in its cavity. Because the filament bundle in the cavity of the microwave resonance detector is a filament bundle segment with a certain length, the filament bundle density data detected here is the density of the filament bundle segment with a certain length, that is, the filament bundle density of the unit segment. That is, in step S1, the filament bundle density of each unit segment on the filament bundle can be obtained using a microwave resonance detector. Of course, in addition to using a microwave resonance detector to detect the filament bundle density, other conventional methods can also be used, which are not limited here.

[0055] Step S2: Calculate the number of joints of the tow to be detected according to the tow density of each unit segment.

[0056] Specifically, the density of the tow at the joint is generally greater than the density of the normal tow, so by comparing the tow densities of the various unit segments obtained in step S1, it can be determined which unit segment has the joint.

[0057] Step S3: Calculate the tow density process capability index according to the tow density of each unit segment.

[0058] The process capability index refers to the degree to which the process capability meets the product quality standard requirements (specification range, etc.), recorded as CPK. The process capability index is also called the process capability index, which mainly represents the actual processing capability of the process under control (stable state) for a certain period of time. It is the inherent capability of the process, or it is the ability of the process to ensure quality. The process referred to here refers to the process of the comprehensive action of five basic quality factors such as operators, machines, raw materials, process methods and production environment, that is, the production process of product quality.

[0059] Specifically, the method for obtaining the tow density process capability index may include:

[0060] Obtaining an average density value of the tow to be detected according to the tow density of each unit segment of the tow to be detected;

[0061] Set the upper and lower limits of tow density;

[0062] Calculated according to the upper limit value, lower limit value and average density value respectively.

[0063] Step S4: judging the quality of the tow to be tested according to the tow density process capability index and the number of joints.

[0064] Specifically, during the production of the tow, the tow may break due to the instability of the processing or the quality of the raw materials. In order to ensure the continuity of the tow, the broken tow will be spliced ​​to form a joint. After repeated research in the actual production process, the applicant found that in addition to the influence of the tow density, the number of tow joints also has a great influence on the suction resistance and weight of the filter rod, and will cause wire breakage during the filter rod forming process, affecting the filter rod production efficiency and increasing the tow consumption. Therefore, in order to further improve the quality and production efficiency of the filter rod, it is necessary to control the number of joints within a certain range. Specifically, for a single-package tow, the number of tow joints can be controlled within 2, and for a multi-package tow, the average number of joints for each package of tow is controlled within 2.

[0065] The method collects online production data of tow density and joints, and performs statistics and analysis on the above data to achieve real-time supervision of tow quality, improve the quality stability of the tow, and enhance the control level of the production process.

[0066] Exemplarily, calculating the number of joints of the tow to be detected according to the tow density of each unit segment (ie, step S2) includes:

[0067] Step S21: comparing the fiber bundle density of each unit segment with a preset range respectively, and when the fiber bundle density of the unit segment is within the preset range, determining that the unit segment is a joint position;

[0068] Step S22: Accumulate the number of all joint positions on the to-be-detected yarn bundle to obtain the number of joints.

[0069] Optionally, a method for obtaining the preset range includes:

[0070] Step A1: Detect the standard tow and the tow with a joint respectively to obtain the tow density of each unit segment on the standard tow and the tow density of each unit segment on the tow with a joint; wherein the standard tow is a tow without a joint and without a break.

[0071] Specifically, a standard tow and a tow with a joint are selected respectively, and then these two tows are used for production respectively. During the production process, the same method as step S1 is used, that is, the tow density of each unit segment on the normal standard tow and the tow density of each unit segment on the tow with a joint are collected respectively through a microwave resonance detector arranged upstream of the opener.

[0072] Step A2: Determine a tow density threshold value according to the tow density of each unit segment on the standard tow.

[0073] That is, the bundle density threshold corresponding to the normal bundle is obtained according to the bundle density analysis of the collected normal standard bundles. As mentioned above, the joint is made up of broken bundles, so the density of the joint is generally greater than the density of the normal bundle. Based on this, the joint can be screened out according to the bundle density threshold corresponding to the normal bundle, and then the density value corresponding to the joint can be obtained.

[0074] Specifically, the average value and standard deviation of the tow density of each section of the collected normal standard tow may be obtained, and the tow density threshold may be determined using the obtained average value and standard deviation.

[0075] Step A3: for the strand density of each unit segment on the strand with the joint, select each strand density greater than the strand density threshold;

[0076] That is, by comparing the collected bundle density of each unit segment of the bundle with a joint with the bundle density threshold, data greater than the bundle density threshold is screened out from all bundle densities of the bundle with a joint, which can be considered as the bundle density corresponding to the joint.

[0077] Step A4: Determine a preset range based on all the tow densities selected in the previous step.

[0078] That is, by analyzing the selected density data, a preset range that can be used to characterize the joint is obtained. Optionally, the mean and standard deviation of the selected tow densities can be obtained, and the preset range is determined based on the mean and standard deviation of the selected tow densities. Alternatively, the maximum and minimum values ​​can be determined from the selected tow densities, and the preset range is determined with the maximum and minimum values ​​as boundaries, that is, the preset range is a data set between the minimum value and the maximum value.

[0079] Exemplarily, obtaining the density of each unit segment on the tow to be detected includes:

[0080] During the processing of the tow to be tested, the density and movement speed of the tow to be tested are obtained in real time;

[0081] Determine the density of each unit segment of the tow according to the density and the movement speed;

[0082] The densities of each tow are summarized to construct a tow density database.

[0083] Specifically, obtaining the density of each unit segment on the tow to be detected includes:

[0084] A microwave sensor and a speed sensor are respectively arranged upstream of the opener;

[0085] The speed sensor obtains the moving speed of the tow to be detected at regular intervals, and determines the detection time according to the preset length and the moving speed currently detected by the speed sensor. When the detection time is reached, the microwave sensor obtains the tow density of the tow unit segment located inside it, and records the tow density of the unit segment until the end of the tow to be detected enters the opener;

[0086] A tow density database is constructed based on all the tow densities obtained by recording.

[0087] That is, after the speed sensor collects speed data, the calculation unit will calculate according to the preset length and the currently collected speed data to obtain a detection time. When the detection time is reached, the microwave sensor will be triggered to collect the yarn bundle density, and the yarn bundle density of this unit segment will be recorded and stored. Then, after a period of time, the speed sensor will collect speed data again. Similarly, the calculation unit will calculate again according to the preset length and the speed data collected this time to obtain another detection time. When this detection time is reached, the microwave sensor will be triggered again to collect the yarn bundle density, and the yarn bundle density of this unit segment will be recorded and stored. Repeat the above steps until the end of the yarn bundle to be detected enters the opener (or leaves the microwave sensor).

[0088] Specifically, in the present application, the principle of data sampling frequency is to reduce the amount of data on the basis of ensuring effective response to the real process. Optionally, the equipment operation signal of the filter rod forming machine can be used as a reference, and the unified acquisition frequency is 1ms / piece (that is, one data is collected per centimeter of tow). That is, the preset length is set to 1cm, the tow movement speed v is collected by the speed sensor, and the detection time t=1 / v is calculated according to the preset length and movement speed. When the detection time t is reached, the microwave sensor is triggered to collect the tow density.

[0089] Furthermore, the triggering rules for data collection are: the index parameters (including tow density and number of joints) trigger collection through the tow joint signal and enter the parameter index setting range. When the tow is in use, the use process data is collected in a timely manner, and the data in the idling state of the equipment is automatically eliminated. The process capability index and the number of joints of a single package of tow are configured in a parameterized form to ensure that the data used for analysis is in the corresponding use state.

[0090] Furthermore, the data collection monitoring rules and evaluation rules for the indicators of tow density and the number of joints of a single package of tow can be managed, and flexible settings can be provided.

[0091] Specifically, in the production process, each package of tow is taken as the collection unit. Under the premise that the operating signal exists, the collection of real-time data of process parameters within the time range from the first use of the tow package and the filter rod forming machine being in working state to the completion of the use of the package of tow is defined as a single package of tow data set. The single package of tow data set can be divided into a valid data set and an invalid data set, among which the valid data set can be further divided into a data set within the set range (i.e., a tow density database) and a data set of the number of times exceeding the set range (i.e., the number of joints).

[0092] like Figure 2 As shown, the data collected during the use of each package of tow is first defined, starting from the receipt of the tow contact signal and entering the parameter index setting range, and ending at the receipt of the next tow contact signal and leaving the parameter index setting range. The data within this range is the full data set of the density of the package of tow (i.e., the single package of tow data set). Among them, the data collected during the use of the package of tow and the working state of the filter rod forming machine are divided into valid data sets.

[0093] Furthermore, the data in the valid data set will be defined as process capability data (i.e., tow density) with the data between the contact signal and entering the parameter index setting range as the starting point, the next contact signal and leaving the parameter index setting range as the end point, and the data that meets the parameter index range. The data can be analyzed by using the control chart, and the process capability index CPK is calculated and evaluated, that is, the contact signal and the parameter collection time are used as the reference axis, and the first data time point when the collection parameter enters the parameter setting range after the contact signal is obtained is defined as the start of valid data; the next contact signal and the parameter collection time are used as the reference axis, and the last data time point when the collection parameter enters the parameter setting range after the next contact signal is obtained is defined as the end of valid data; data other than valid data in the tow single package data set should be eliminated. That is, the production data including the standby uncontrollable stage is eliminated, and only the valid data in the stable state is used to calculate CPK. In this way, the measurement data of the standby uncontrollable stage is eliminated to filter the repeated data of the standby uncontrollable stage, and ensure that the data used for analysis is in use.

[0094] Similarly, the data between the contact signal and entering the parameter index setting range is defined as the starting point, the next contact signal and leaving the parameter index setting range is defined as the number of single-package joints (i.e., the number of joints), that is, the number of times the effective data leaves the setting range and enters the setting range again in real-time collection. Specifically, the number of single-package joints Xn = the cumulative number of single-package tow joints. That is, by eliminating the number of measured data in the standby uncontrollable stage, the number of repeated recorded data of the standby stage measurement data is filtered to ensure that the number of tows used is consistent with the measured number.

[0095] Specifically, the calculation formula of the process capability index CPK of tow density is:

[0096] CPK=Min(CPKu,CPKl)

[0097] The calculation formulas for CPKu and CPKl are:

[0098]

[0099]

[0100] Among them, USL (Upper specification limit) and LSL (Low specification limit) represent the upper and lower limits of the tow density, respectively, which can be set according to actual conditions. Represents the average value of the tow density, specifically σ represents the standard deviation of the tow density.

[0101] Furthermore, when the to-be-tested silk bundle is a multi-package silk bundle, the cigarette silk bundle quality testing method further comprises:

[0102] The mean and standard deviation of the process capability index of the tow density and the mean and standard deviation of the number of joints corresponding to each bundle of tows are calculated respectively;

[0103] The quality of the yarn bundle to be tested is judged according to the mean and standard deviation of the yarn bundle density process capability index and the number of joints, respectively.

[0104] Furthermore, the average number of joints can be calculated from the single package joint number data set, specifically,

[0105] Specifically, when the tow to be detected is a multi-package tow, the tow usage process data is eliminated and classified as a single-package tow to form the single-package tow process data, and then for each package tow, the method mentioned above is used to calculate the CPK and the number of joints of the package tow according to the single-package tow process data of the package tow. Optionally, the start and end of the single-package tow can be marked according to the following rules:

[0106] Contact signal: the start of the single-bundle process, which can be judged by the overlap mark signal between bundles or other online measuring instrument signals;

[0107] Next contact signal: that is, the single bundle process is finished, which can be judged by the overlap mark signal between bundles or other online measuring instrument signals.

[0108] The method provided by the present invention adopts microwave detection technology and electronic control technology, combined with the working process of the forming machine, and collects online production data of tow density and joints to complete the statistics, analysis, and stability evaluation of related indicators of the above data, and uses the evaluation output results to achieve real-time supervision of the quality of tow raw materials, thereby improving the guarantee capability of tow raw materials and enhancing the level of process control.

[0109] Accordingly, if Figure 3 As shown, one embodiment of the present invention further provides a tobacco strand quality detection system, comprising:

[0110] Density acquisition module 1, used to acquire the density of each unit segment on the tow to be detected;

[0111] A first calculation module 2, used for calculating the number of joints of the tow to be detected according to the tow density of each unit segment;

[0112] A second calculation module 3 is used to calculate the tow density process capability index according to the tow density of each unit segment;

[0113] The judgment module 4 is used to receive the number of joints output by the first calculation module 2 and the tow density process capability index output by the second calculation module 3, and judge the quality of the tow to be tested according to the tow density process capability index and the number of joints.

[0114] Exemplarily, the first calculation module 2 includes:

[0115] The joint determination unit 21 is used to compare the fiber bundle density of each unit segment with a preset range. When the fiber bundle density of the unit segment is within the preset range, the joint determination unit 21 determines that the unit segment is a joint position.

[0116] The statistical unit 22 is used to accumulate the number of all joint positions on the to-be-detected yarn bundle to obtain the number of joints.

[0117] Exemplarily, the preset range is pre-stored in the joint determination unit 21, and the method for obtaining the preset range includes:

[0118] The standard tow and the tow with a joint are tested respectively to obtain the tow density of each unit segment on the standard tow and the tow density of each unit segment on the tow with a joint; wherein the standard tow is a tow without a joint and without a break;

[0119] Determine a tow density threshold value according to the tow density of each unit segment on the standard tow;

[0120] For the strand density of each unit segment on the strand with a joint, select each strand density greater than a strand density threshold;

[0121] Determine the preset range based on all the tow densities selected in the previous step.

[0122] Exemplarily, the density acquisition module 1 includes:

[0123] The speed sensor 11 is arranged upstream of the opener, and the speed sensor 11 detects the moving speed of the tow to be detected once at a certain interval;

[0124] The calculation unit 12 is used to receive the current movement speed output by the speed sensor 11, and determine the detection time according to the preset length and the current movement speed. When the detection time is reached, the calculation unit sends a trigger signal;

[0125] The microwave sensor 13 is arranged upstream of the opener. The microwave sensor 13 is used to receive the trigger signal output by the calculation unit 12 and be triggered to obtain the yarn density of the yarn unit segment located inside it; specifically, the speed sensor 11 and the microwave sensor 13 are both arranged upstream of the opener, and the speed sensor 11 can be arranged upstream of the microwave sensor 13.

[0126] The storage unit 14 is used to record the tow density of the unit segment acquired by the microwave sensor 13, and to construct a tow density database according to all recorded tow densities.

[0127] Optionally, the equipment operation signal of the filter rod forming machine can be used as a reference, and the unified acquisition frequency is 1ms / data (i.e., one data is collected per centimeter of tow). That is, the preset length is set to 1cm, the tow movement speed v is collected by the speed sensor 11, and the detection time t=1 / v is calculated according to the preset length and the movement speed. When the detection time t is reached, the microwave sensor 13 is triggered to collect the tow density.

[0128] Furthermore, the triggering rules for data collection are: the index parameters (including tow density and number of joints) trigger collection through the tow joint signal and enter the parameter index setting range. When the tow is in use, the use process data is collected in a timely manner, and the data in the idling state of the equipment is automatically eliminated. The process capability index and the number of joints of a single package of tow are configured in a parameterized form to ensure that the data used for analysis is in the corresponding use state.

[0129] Furthermore, the data collection monitoring rules and evaluation rules for the indicators of tow density and the number of joints of a single package of tow can be managed, and flexible settings can be provided.

[0130] Specifically, in the production process, each package of tow is used as a collection unit. Under the premise that the operation signal exists, the collection of real-time data of process parameters within the time range from the first use of the tow package and the filter rod forming machine is in working state to the end of the use of the tow package is defined as a tow single package data set. The tow single package data set can be divided into a valid data set and an invalid data set, wherein the valid data refers to the data collected during the use of the tow package and the filter rod forming machine is in working state. The valid data set can be divided into a data set within the set range (i.e., the tow density database) and a data set of the number of times exceeding the set range (i.e., the number of joints).

[0131] Furthermore, the data in the valid data set will be defined as process capability data (i.e., tow density) with the data between the contact signal and entering the parameter index setting range as the starting point, the next contact signal and leaving the parameter index setting range as the end point, and the data that meets the parameter index range. The data can be analyzed by using the control chart, and the process capability index CPK is calculated and evaluated, that is, the contact signal and the parameter collection time are used as the reference axis, and the first data time point when the collection parameter enters the parameter setting range after the contact signal is obtained is defined as the start of valid data; the next contact signal and the parameter collection time are used as the reference axis, and the last data time point when the collection parameter enters the parameter setting range after the next contact signal is obtained is defined as the end of valid data; data other than valid data in the tow single package data set should be eliminated. That is, the production data including the standby uncontrollable stage is eliminated, and only the valid data in the stable state is used to calculate CPK. In this way, the measurement data of the standby uncontrollable stage is eliminated to filter the repeated data of the standby uncontrollable stage, and ensure that the data used for analysis is in use.

[0132] Similarly, the data between the contact signal and entering the parameter index setting range is defined as the starting point, the next contact signal and leaving the parameter index setting range is defined as the number of single-package joints (i.e., the number of joints), that is, the number of times the effective data leaves the setting range and enters the setting range again in real-time collection. Specifically, the number of single-package joints Xn = the cumulative number of single-package tow joints. That is, by eliminating the number of measured data in the standby uncontrollable stage, the number of repeated recorded data of the standby stage measurement data is filtered to ensure that the number of tows used is consistent with the measured number.

[0133] Furthermore, when the tow to be detected is a multi-package tow, the tow usage process data is eliminated and classified as a single-package tow to form single-package tow process data, and then for each package tow, the method mentioned above is used to calculate the CPK and number of joints of the package tow according to the single-package tow process data of the package tow. Optionally, the start and end of the single-package tow can be marked according to the following rules:

[0134] Contact signal: the start of the single-bundle process, which can be judged by the overlap mark signal between bundles or other online measuring instrument signals;

[0135] Next contact signal: that is, the single bundle process is finished, which can be judged by the overlap mark signal between bundles or other online measuring instrument signals.

[0136] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A method for detecting the quality of tobacco strands, characterized in that: include: The density and movement speed of the tow to be detected are obtained in real time to obtain the tow density of each unit segment on the tow to be detected; Calculating the number of joints of the to-be-detected tow according to the tow density of each unit segment, including: comparing the tow density of each unit segment with a preset range respectively, and judging that the unit segment is a joint position when the tow density of the unit segment is within the preset range; accumulating the number of all joint positions on the to-be-detected tow to obtain the number of joints; the method for obtaining the preset range includes: detecting the standard tow and the tow with joints respectively, and obtaining the tow density of each unit segment on the standard tow and the tow density of each unit segment on the tow with joints; wherein the standard tow is a tow without joints and without breaks; determining a tow density threshold according to the tow density of each unit segment on the standard tow; selecting each tow density greater than the tow density threshold from the tow density of each unit segment on the tow with joints; determining the preset range according to all tow densities selected in the above step; Calculate the process capability index of the tow density according to the tow density of each unit segment, the process capability index of the tow density is obtained through process capability data, the process capability data is, in the effective data set of the tow density, the data that starts from the contact signal and enters the parameter index setting range, the data that ends at the next contact signal and leaves the parameter index setting range, and satisfies the parameter index range, the effective data set of the tow density is the data set of the tow single package except the effective data; The quality of the tow to be tested is judged according to the tow density process capability index and the number of joints.

2. The method for detecting the quality of tobacco strands according to claim 1, characterized in that: The step of obtaining the density of each unit segment of the tow to be detected comprises: A microwave sensor and a speed sensor are respectively arranged upstream of the opener; The speed sensor obtains the movement speed of the tow to be detected at regular intervals, and determines the detection time according to the preset length and the movement speed currently detected by the speed sensor. When the detection time is reached, the microwave sensor obtains the tow density of the tow unit segment located inside it, and records the tow density of the unit segment until the end of the tow to be detected enters the opener.

3. The method for detecting the quality of tobacco strands according to claim 2, characterized in that: Also includes: The tow density database is constructed according to all the tow densities obtained by recording.

4. The method for detecting the quality of tobacco strands according to claim 1, characterized in that: When the to-be-tested silk bundle is a multi-package silk bundle, the cigarette silk bundle quality testing method further comprises: Respectively calculating the mean and standard deviation of the tow density process capability index and the mean and standard deviation of the number of joints corresponding to each bundle of tows; The quality of the tow to be tested is judged according to the tow density process capability index and the mean and standard deviation of the number of joints, respectively.

5. A tobacco strand quality detection system, used to implement the detection method according to any one of claims 1 to 4, characterized in that: include: A density acquisition module is used to acquire the density of each unit segment on the tow to be detected; A first calculation module, used for calculating the number of joints of the to-be-detected tow according to the tow density of each unit segment; A second calculation module is used to calculate a tow density process capability index according to the tow density of each unit segment; A judgment module is used to receive the number of joints output by the first calculation module and the tow density process capability index output by the second calculation module, and judge the quality of the tow to be tested according to the tow density process capability index and the number of joints.

6. The tobacco strand quality detection system according to claim 5, characterized in that: The first calculation module includes: A joint determination unit, used to compare the fiber bundle density of each unit segment with a preset range respectively, and when the fiber bundle density of the unit segment is within the preset range, the joint determination unit determines that the unit segment is a joint position; The statistical unit is used to accumulate the number of all joint positions on the to-be-detected yarn bundle to obtain the number of joints.

7. The tobacco strand quality detection system according to claim 6, characterized in that: The method for obtaining the preset range includes: The standard tow and the tow with a joint are tested respectively to obtain the tow density of each unit segment on the standard tow and the tow density of each unit segment on the tow with a joint; wherein the standard tow is a tow without a joint and without a break; Determining a tow density threshold value according to the tow density of each unit segment on the standard tow; For the strand density of each unit segment on the strand with the joint, select each strand density greater than the strand density threshold; The preset range is determined according to all the tow densities selected in the previous step.

8. The tobacco strand quality detection system according to claim 5, characterized in that: The density acquisition module comprises: A speed sensor is arranged upstream of the opener, and the speed sensor detects the moving speed of the to-be-detected yarn bundle once at a certain interval; A calculation unit, used for receiving the motion speed currently output by the speed sensor, and determining a detection time according to a preset length and the current motion speed, and when the detection time is reached, the calculation unit sends a trigger signal; A microwave sensor is arranged upstream of the opener, and is used to receive the trigger signal output by the calculation unit and be triggered to obtain the tow density of the tow unit segment located inside the microwave sensor; The storage unit is used to record the tow density of the unit segment acquired by the microwave sensor, and to construct a tow density database according to all the recorded tow densities.

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