Synchronous twisting and connecting method for geometric compensation of composite cigarette segments

Abstract

The invention belongs to the technical field of tobacco machinery, and particularly relates to a synchronous twisting and connecting method for sectional geometric compensation of a composite cigarette. According to the method, the physical parameters of all the sections are measured, the extrusion force relation is tested, the minimum compression amount is calculated based on the non-slip criterion, the receding groove with the specific depth and length is formed in the corresponding section of the washboard channel, synchronous pure rolling of all the sections under the unified pressing-in condition is achieved, the problems of wrinkling, dislocation and roundness deterioration are effectively solved, and the twisting and connecting quality and efficiency are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tobacco machinery, and particularly relates to a synchronous rolling method for sectional geometric compensation of composite cigarettes. BACKGROUND

[0002] In the manufacturing process of composite cigarettes, the cigarettes composed of multiple heterogeneous materials such as filter rods, PLA1 (poly-lactic acid section), core rods and hollow tube base rods need to be transported and formed into shape in the channel formed by the rolling plate and the rolling wheel. The ideal rolling state is to keep pure rolling between the cigarettes and the rolling parts to avoid appearance defects such as crinkling of the tipping paper, misplacement between sections and deterioration of roundness caused by relative sliding.

[0003] However, the rolling method in the prior art usually adopts the mode of overall pressure and empirical fine-tuning. Since the sections of the composite cigarettes have significant differences in material properties, outer diameters, densities and surface friction coefficients, it is difficult for the unified extrusion condition to meet the pure rolling requirements of all sections. This leads to insufficient pressure of some sections and easy sliding, while excessive pressure of some other sections causes stress concentration and deformation. In addition, the channel structure of the existing rolling plate is usually designed in a "one-size-fits-all" manner, lacking geometric compensation mechanisms for different sections, and the friction pairing is not matched with the different contact relationships of primary and secondary rolling. Therefore, it is necessary to rely on the experience of operators to make repeated trial and error in production, which has problems such as poor stability, low consistency, long parameter adjustment period and difficulty in adapting to rapid switching of multiple specifications. SUMMARY

[0004] The present application aims to solve the technical problems that the sections of the composite cigarettes cannot be synchronously pure-rolled due to the adoption of overall pressure and lack of sectional compensation in the existing rolling method of composite cigarettes, which easily causes crinkling, misplacement and roundness deterioration, and relies on experience trial and error with poor stability and consistency.

[0005] In order to solve the above technical problems, the present application is implemented as follows: The present application provides a synchronous rolling method for sectional geometric compensation of composite cigarettes, comprising the following steps: Step one: measuring the physical parameters of the materials of each section of the composite cigarettes, the physical parameters including diameter, length and density; Step two: performing extrusion force test on the materials of each section of the composite cigarettes to obtain the relationship curve between the extrusion force and the compression amount of each section of the material; Step three: calculating the minimum compression amount of each section of the material in the rolling process based on the non-slip criterion, and determining the unified nominal pressure based thereon; Step four: setting a retreat groove at the position corresponding to each section of the material on the rolling plate channel, the depth of the retreat groove being determined based on the minimum compression amount, the diameter difference and the unified nominal pressure of each section of the material, and the length of the retreat groove being set based on the length of each section of the material and containing a process allowance.

[0006] Optionally, in step one, the material of each section of the composite cigarette includes a filter rod, a PLA1, a tobacco core rod and a hollow tube base rod.

[0007] Optionally, in step two, the extrusion force test is performed by a universal material tensile testing machine, and a relationship curve between the extrusion force and the compression amount is obtained by fitting the compression displacement and the load data by a least square method.

[0008] Optionally, in step three, the non-slip criterion is derived based on a force analysis of the composite cigarette between the rolling plate and the rolling wheel, and the force analysis includes a relationship condition between the static friction force and the contact pressure.

[0009] Optionally, the non-slip criterion satisfies the following condition: ; wherein, m is the mass of the cigarette, g is the acceleration of gravity, θ is an included angle between a working surface of the rolling plate and a vertical direction, f 1 is a static friction factor of the rolling wheel and the cigarette, f 2 is a static friction factor of the rolling plate and the cigarette, p is the extrusion force, ω is an angular velocity of the rolling wheel, r is a radius of the cigarette.

[0010] Optionally, in step four, the depth of the retreat groove is calculated by a formula d3=d2+d-d1, wherein d1 is the compression amount of the current section of material, d2 is a diameter difference between the current section of material and the reference section of material, d3 is the depth of the retreat groove, and d is a unified nominal indentation corresponding to an actual compression amount.

[0011] Optionally, in step four, the length of the retreat groove is 1mm longer than the length of the corresponding section of material.

[0012] Optionally, the method is applied to a first rolling and a second rolling process. The first rolling is for a double-length cigarette composed of the tobacco core rod, the hollow tube base rod and the PLA1. The second rolling is for a double-length composite cigarette formed by combining the single-length cigarette formed by the first rolling and the filter rod.

[0013] Optionally, in the second rolling, the depth of the retreat groove is determined based on a diameter difference between the filter rod and the single-length cigarette formed by the first rolling and a minimum compression amount.

[0014] Compared with the prior art, the present application has the following beneficial effects: (1) Realize synchronous pure rolling and stable transportation: through setting retreat grooves in sections to make geometric compensation, each section obtains matched contact and load path under unified pressing condition, which effectively suppresses wrinkling, misplacement and roundness deterioration.

[0015] (2) Provide calculable and replicable engineering method: taking "non-slip criterion" as theoretical core, key parameters are determined through quantitative calculation, which replaces trial-and-error method depending on experience, so that installation parameter adjustment path is clear, reviewable and replicable.

[0016] (3) Reduce energy consumption and abrasion: stable rubbing is realized at lower pressing level, which reduces internal stress of cigarette and abrasion of rubbing device components.

[0017] (4) Improve adaptability and consistency: contact relationship of primary and secondary rubbing is systematically brought into design, forming standardized process window for different materials and specifications, which significantly improves batch consistency and mass production yield. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings. Figure 1 A composite cigarette segment material composition diagram provided by the present application; Figure 2 A composite cigarette stress analysis diagram provided by the present application; Figure 3 A double-length composite cigarette diagram formed by the first rubbing provided by the present application; Figure 4 A same cigarette diameter schematic diagram provided by the present application; Figure 5 A different cigarette diameter and rubbing plate without retreat groove schematic diagram provided by the present application; Figure 6 A different cigarette diameter and rubbing plate with retreat groove schematic diagram provided by the present application; Figure 7 A rubbing plate schematic diagram provided by the present application; Figure 8 A single-length cigarette diagram formed by the second rubbing provided by the present application; Figure 9 A same cigarette diameter schematic diagram provided by the present application; Figure 10 A different cigarette diameter and rubbing plate without retreat groove schematic diagram provided by the present application; Figure 11Different cigarette diameter and the retreating slot of the paddle are shown in the schematic view provided by the present application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0020] The terms "first", "second", and the like in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally a category and do not limit the number of objects, for example, the first object can be one or more. In addition, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in an "or" relationship.

[0021] The embodiment of the present application provides a synchronous rolling method for composite cigarette sectional geometry compensation, comprising the following steps: Step one: measure the physical parameters of each section of the composite cigarette material, including diameter, length and density; Step two: test the extrusion force of each section of the composite cigarette material to obtain the relationship curve between the extrusion force and the compression amount of each section of the material; Step three: based on the non-slip criterion, calculate the minimum compression amount of each section of the material in the rolling process, and determine the unified nominal indentation accordingly; Step four: set a retreating slot at the position corresponding to each section of the material on the paddle channel, the depth of the retreating slot is determined based on the minimum compression amount, the diameter difference and the unified nominal indentation of each section of the material, and the length of the retreating slot is set based on the length of each section of the material and contains a process allowance.

[0022] In step one, referring to Figure 1 As shown in the figure, each section of the composite cigarette material includes a filter rod 1, a PLA1 2, a tobacco core rod 3 and a hollow tube base rod 4, wherein the filter rod 1 is mainly composed of acetate fiber, and the main function is to filter harmful substances generated during the combustion of the composite cigarette. PLA1 2 is polylactic acid, which is yellow in color, and the main function is to reduce the temperature transferred to the filter rod during the combustion of the composite cigarette. The tobacco core rod 3 is mainly composed of strip tobacco, which is the combustion section of the composite cigarette. The hollow tube base rod 4 is mainly composed of acetate fiber, and the main function is to reduce the temperature transferred to the filter rod during the combustion of the composite cigarette.

[0023] In step two, the extrusion pressure test is performed using a universal tensile testing machine, and the compression displacement and load data are fitted using the least squares method to obtain the relationship curve between the extrusion pressure and the compression amount.

[0024] In step three, the non-slip criterion is derived from the force analysis of the composite cigarette between the rubbing board and the rubbing wheel. The force analysis includes the relationship between static friction and contact pressure.

[0025] The non-slip criterion satisfies the following conditions: (1); in, m For the quality of cigarettes, g It is the acceleration due to gravity. θ The angle between the working surface of the washboard and the vertical direction. f 1 represents the coefficient of static friction between the cigarette-rolling roller and the cigarette. f 2 represents the coefficient of static friction between the washboard and the cigarette. p For extrusion pressure, ω The angular velocity of the cigarette-rolling wheel, r Let be the radius of the cigarette.

[0026] From the above formula for the slippage criterion, it can be seen that increasing... f 1. f 2. , , r and decrease m and All of these measures can reduce the slippage of the composite cigarette within the rubbing board. Specifically, when the deformation of the composite cigarette is small: the friction coefficient between the rubbing wheel and the composite cigarette should be larger, the friction coefficient between the rubbing board and the composite cigarette should be larger, the squeezing force of the rubbing wheel on the composite cigarette should be appropriate, the rubbing wheel should have a larger angular velocity, the material mass of each section of the composite cigarette should be smaller, and the installation angle of the rubbing board should be smaller.

[0027] In step four, the depth of the relief groove is calculated using the formula d3=d2+d-d1, where d1 is the compression amount of the current segment material, d2 is the diameter difference between the current segment material and the reference segment material, d3 is the depth of the relief groove, and d is the actual compression amount corresponding to the uniform nominal pressing.

[0028] In step four, the length of the relief groove is 1 mm longer than the length of the corresponding material segment.

[0029] The method described above is applied to the first and second rubbing processes; The first twisting is for a double-length cigarette composed of a core rod, an empty tube base rod, and PLA1. The second twisting refers to the formation of a double-length composite cigarette by combining the single-length cigarette formed by the first twisting with the filter rod.

[0030] In the second twisting process, the depth of the relief groove is determined based on the difference in diameter between the filter rod and the single-length cigarette formed by the first twisting process, and the minimum compression amount.

[0031] The following detailed description of the synchronous splicing method for segmented geometric compensation of composite cigarettes provided by the present invention is based on specific embodiments.

[0032] Example: This embodiment uses a composite cigarette composed of a core rod, a hollow tube base rod, PLA1 (polylactic acid segment), and a filter rod as an example to illustrate the specific implementation process of this method. The method includes the following steps in sequence: Step 1: Measure the physical parameters of each segment of the composite cigarette material.

[0033] The density of the cigarette was obtained by measuring the mass and volume of each segment. Since the cigarette is made of a soft material, its diameter is difficult to measure directly. In this embodiment, a 3020 imaging instrument was used to measure the circumference, which was then converted to diameter. The physical parameters of each segment obtained from the measurements are shown in Table 1.

[0034] Table 1 Physical parameters of materials in each segment of the composite cigarette Step 2: Extrusion pressure test of each section of the composite cigarette.

[0035] Compression tests were conducted on PLA1, hollow tube base rods, and cigarette core rods using a universal tensile testing machine. To ensure data reliability, five test samples were prepared for each material. Based on the cigarette displacement and load data recorded by the testing machine, the relationship between the compressive force p and the compression amount d for each segment of the material was obtained using Origin software and the least squares method.

[0036] The relation for PLA1 is: (2) The relationship between the empty tube base rod and the following is: (3) The relationship between the cigarette core rod and the following formula is: (4) The R-squared values ​​of the above fitted curves are all greater than 0.997, indicating that the fitting curves of the extrusion pressure and compression amount of each segment of the cigarette have a good fit.

[0037] Step 3: Calculate the minimum compression of each material segment based on the non-slip criterion.

[0038] First, the forces acting on the composite cigarette in the splicing device are analyzed, and a mechanical model is established (e.g., Figure 2(As shown). Based on the theorem of motion of the center of mass and the theorem of angular momentum, the condition for a compound cigarette to roll purely (the criterion for no slippage) is derived as follows: ; in, m For the quality of cigarettes, g It is the acceleration due to gravity. θ The angle between the working surface of the washboard and the vertical direction (52.125° in this embodiment). f 1 represents the coefficient of static friction between the cigarette-rolling roller and the cigarette. f 2 represents the coefficient of static friction between the washboard and the cigarette. p For extrusion pressure, ω The angular velocity of the cigarette-rubbing wheel is 60 r / min in this embodiment. r Let be the radius of the cigarette.

[0039] Subsequently, the physical parameters and friction coefficients of each material segment (PLA1 length L is 100mm, mass...) were determined. m It is 1.141 g, with an included angle. θ The angle is 52.125°, and the angular velocity is... The speed is 60 r / min, and the radius is... r The diameter is 168.6105 mm; the static friction coefficient between the cigarette-rubbing roller and the tipping paper is 0.98; the static friction coefficient between the rubbing board and PLA1 is 1.2; the length L of the empty tube base rod is 100 mm; the mass... m It is 1.105 g, with an included angle. θ The angle is 52.125°, and the angular velocity is... The speed is 60 r / min, and the radius is... r The diameter is 168.442 mm; the static friction coefficient between the cigarette rolling wheel and the tipping paper is 0.98; the static friction coefficient between the rubbing plate and the empty tube base rod is 0.95; the length L of the cigarette core rod is 100 mm; the mass... m It is 2.237 g, with an included angle. θ The angle is 52.125°, and the angular velocity is... The speed is 60 r / min, and the radius is... r The static friction coefficient between the rubbing wheel and the tipping paper is 0.98, and the static friction coefficient between the rubbing board and the cigarette core rod is 1.53. Substituting these values ​​into equation (1) and combining them with the extrusion pressure-compression amount relationship obtained in step two (equation (2) - equation (4)), we can solve for the minimum extrusion pressure p required to satisfy the non-slip condition, and then obtain the corresponding minimum compression amount.

[0040] Minimum compressive force p 4.5×10 -3 Minimum compression of PLA1 under non-slip conditions at N: 0.013 mm.

[0041] Minimum compressive force p It is 4.36×10-3 Minimum compression of the empty tube base rod under non-slip conditions: 0.044 mm.

[0042] Minimum compressive force p It is 8.829×10 -3 Minimum compression of the wick rod under non-slip conditions at N: 0.015 mm.

[0043] To ensure that none of the segments slip, the maximum value is taken as the corresponding actual compression amount to be uniformly pushed in. d ,Right now d =0.044 mm.

[0044] Step 4: Optimization design of the relief groove structure.

[0045] On the washboard channel, relief grooves are made at positions corresponding to each section of material. The depth of the relief grooves is calculated using the formula d3=d2+d-d1.

[0046] First-time joint relief groove design: such as Figure 3 As shown, the first splicing is for a double-length cigarette consisting of a core rod, an empty tube base rod, and PLA1. The cigarette is covered with a layer of splicing paper, wherein the PLA1 is 15mm long, the empty tube base rod is 10mm long, and the core rod is 24mm long.

[0047] Based on diameter test results, PLA1 has a diameter of 7.171 mm, the hollow tube base rod has a diameter of 6.906 mm, and the core rod has a diameter of 7.121 mm. Based on the calculated minimum compression of the cigarette under non-slip conditions, PLA1 has a minimum compression of 0.013 mm, the hollow tube base rod has a minimum compression of 0.044 mm, and the core rod has a minimum compression of 0.015 mm. Since each segment of the composite cigarette needs to exceed the total compression of the composite cigarette while satisfying its own compression requirements, the minimum compression of PLA1 under non-slip conditions is 0.019 mm, the minimum compression of the core segment is 0.019 mm, and the minimum compression of the hollow tube base rod is 0.044 mm.

[0048] When the diameters of all segments of a composite cigarette are the same, such as Figure 4 As shown, d represents the theoretical compression amount of 0.044 mm (compression amount of empty tube base rod).

[0049] When the diameters of the materials in different sections of a composite cigarette are different and the corrugated board has no relief groove, such as Figure 5 As shown, d1 is the compression amount of the empty tube base rod (0.044 mm), d2 is the difference between the diameter of PLA1 and the diameter of the empty tube base rod (0.265 mm), and d is the actual compression amount of the washboard (0.309 mm).

[0050] When the diameters of the materials in different sections of a composite cigarette are different and the corrugated board has recessed grooves, such as Figure 6As shown, d1 is the PLA1 compression amount of 0.019mm, d2 is the difference between the PLA1 diameter and the empty tube base rod diameter of 0.265mm, d3 is the depth of the relief groove at the corresponding position of PLA1, d4 is the depth of the relief groove at the corresponding position of the wick rod, and d is the actual compression amount of 0.044mm (empty tube base rod compression amount). According to d3=d2+dd 1， We can obtain d3 as 0.29mm, and similarly d4 as 0.25mm. By adding the washboard relief groove, the theoretical minimum compression of the washboard is reduced from 0.309mm to 0.044mm, which greatly reduces cigarette deformation.

[0051] The design is based on the lengths of PLA1, the core section, and the empty tube base rod. The empty tube base rod is 10mm long, PLA1 is 15mm long, and the core section is 24mm long. Due to manufacturing errors, to prevent interference between the composite cigarette sections and the relief groove, the relief groove length of the PLA1 section is designed to be 1mm longer than the PLA1 section, and the relief groove length of the core section is designed to be 1mm longer than the core section. A schematic diagram of the flushing board is shown below. Figure 7 As shown in Table 2, the length and depth of the relief groove are as follows.

[0052] Table 2. Length and Depth of Relief Groove The second twisting creates a double-length cigarette, consisting of a core rod, a hollow tube base rod, PLA1, and a filter rod. The double-length cigarette formed in the first twisting is cut and reversed, then combined with the filter rod for a second twisting to form a double-length composite cigarette. Finally, it is cut in the middle of the filter rod, resulting in a single-length cigarette from the second twisting. Figure 8 As shown.

[0053] The first twisting process creates a single-length cigarette wrapped in tipping paper. The friction between the single-length cigarette formed in the first twisting process and the twisting device changes to friction between the tipping paper and the twisting device. The second twisting process involves: the filter rod contacting the rubbing plate, the tipping paper on the filter rod contacting the rubbing wheel, the tipping paper on the single-length cigarette formed in the first twisting process contacting the rubbing plate, and the tipping paper on the single-length cigarette formed in the first twisting process contacting the rubbing wheel.

[0054] The first twisting and splicing resulted in a single-length cigarette with a length of 35mm and a diameter of 7.171mm. The filter rod was 10mm long and had a diameter of 7.108mm. The minimum compression of the single-length cigarette without slippage was 0.019mm, and the minimum compression of the filter rod was 0.037mm.

[0055] When the diameters of all segments of a composite cigarette are the same, such as Figure 9 As shown, d represents the theoretical compression amount of 0.037 mm (compression amount of the filter rod).

[0056] When the diameters of the materials in different sections of a composite cigarette are different and the corrugated board has no relief groove, such as Figure 10 As shown, d1 is the compression amount of the filter rod (0.037 mm), d2 is the difference between the diameter of a single-length cigarette and the diameter of the filter rod (0.063 mm), and d is the actual compression amount of the rubbing board (0.1 mm).

[0057] When the diameters of the materials in different sections of a composite cigarette are different and the corrugated board has recessed grooves, such as Figure 11 As shown, d1 is the compression amount of a single-length cigarette (0.019 mm), d2 is the difference between the diameter of a single-length cigarette and the diameter of the filter rod (0.063 mm), d3 is the depth of the recessed groove at the corresponding position of a single-length cigarette, and d is the actual compression amount (0.037 mm, compression amount of the empty tube base rod). According to d3 = d2 + d - d1, d3 is 0.081 mm.

[0058] The design of the relief groove length is based on the length of a single-length cigarette and the length of the filter rod. The length of a single-length cigarette is 37mm, and the length of the filter rod is 16mm.

[0059] The depth of the recessed groove at the position of the single-length cigarette formed by the first twisting is designed with the filter rod as the zero reference. When the depth at the corresponding position of the filter rod is 0mm, the depth at the corresponding position of the single-length cigarette formed by the first twisting is 0.081mm. The height difference between the two ends is small, making processing difficult. Therefore, opening a recessed groove at this point has little impact on the twisting performance. Thus, the minimum compression amount for the second twisting is 0.081mm.

[0060] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0061] Furthermore, it should be noted that the scope of the methods and systems in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0062] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A synchronous splicing method for segmented geometric compensation of composite cigarettes, characterized in that, Includes the following steps: Step 1: Measure the physical parameters of each segment of the composite cigarette material, including diameter, length, and density; Step 2: Perform extrusion pressure tests on each segment of the composite cigarette material to obtain the relationship curve between the extrusion pressure and the compression amount of each segment. Step 3: Based on the non-slip criterion, calculate the minimum compression of each material segment during the jointing process, and determine the uniform nominal pressing accordingly; Step 4: Set relief grooves at positions corresponding to each material segment on the corrugated board channel. The depth of the relief grooves is determined based on the minimum compression amount, diameter difference, and uniform nominal pressing of each material segment. The length of the relief grooves is set based on the length of each material segment and includes process allowance.

2. The method according to claim 1, characterized in that, In step one, the materials of each segment of the composite cigarette include a filter rod, PLA1, a core rod, and a hollow tube base rod.

3. The method according to claim 1, characterized in that, In step two, the extrusion pressure test is performed using a universal tensile testing machine, and the compression displacement and load data are fitted using the least squares method to obtain the relationship curve between the extrusion pressure and the compression amount.

4. The method according to claim 1, characterized in that, In step three, the non-slip criterion is derived from the force analysis of the composite cigarette between the rubbing board and the rubbing wheel. The force analysis includes the relationship between static friction and contact pressure.

5. The method according to claim 4, characterized in that, The non-slip criterion satisfies the following conditions: ； in, m For the quality of cigarettes, g It is the acceleration due to gravity. θ The angle between the working surface of the washboard and the vertical direction. f 1 represents the coefficient of static friction between the cigarette-rolling roller and the cigarette. f 2 represents the coefficient of static friction between the washboard and the cigarette. p For extrusion pressure, ω The angular velocity of the cigarette-rolling wheel, r Let be the radius of the cigarette.

6. The method according to claim 1, characterized in that, In step four, the depth of the relief groove is calculated using the formula d3=d2+d-d1, where d1 is the compression amount of the current segment material, d2 is the diameter difference between the current segment material and the reference segment material, d3 is the depth of the relief groove, and d is the actual compression amount corresponding to the uniform nominal pressing.

7. The method according to claim 1, characterized in that, In step four, the length of the relief groove is 1 mm longer than the length of the corresponding material segment.

8. The method according to claim 1, characterized in that, The method described above is applied to the first and second rubbing processes; The first twisting is for a double-length cigarette composed of a core rod, an empty tube base rod, and PLA1. The second twisting refers to the formation of a double-length composite cigarette by combining the single-length cigarette formed by the first twisting with the filter rod.

9. The method according to claim 8, characterized in that, In the second twisting process, the depth of the relief groove is determined based on the difference in diameter between the filter rod and the single-length cigarette formed by the first twisting process, and the minimum compression amount.

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