TWI548581B - Method of manufacturing web roll, method of winding web roll and calculation method of internal stress - Google Patents

Description

Net roll manufacturing method, net winding method and internal stress calculation method

The present invention relates to a web roll manufacturing method and a web winding method manufactured by winding a web on a winding core, and more particularly to the following method for manufacturing a web roll and a web roll The winding method is to calculate the net winding condition by calculating the internal stress of the web wound into a roll, and wind the web in accordance with the obtained winding condition.

In the past, a web such as plastic was wound into a roll and shipped to customers. By winding a web that is as long as possible to make a roll, it is possible to transport a large number of nets by transporting one roll, thereby enabling efficient transport.

However, the longer the web is wound up, the greater the possibility that the formed roll will be misaligned or the like. Here, the roll misalignment defect refers to a defect phenomenon in which the position of both side ends of the roll in which the net is wound is a state in which a part of the initial state is deviated from the state after the winding is completed. This volume misalignment defect occurs not only during winding but also when the rolled roll is being handled.

There have been various empirical trials in the past for winding conditions of nets that do not suffer from such defects. The reason is because there is no effective prediction method (simulation) with less error. In addition, when the evaluation of the condition is performed, it takes two weeks or more for the evaluation period, and one sample for evaluation is wound around a net of several hundred to several kilometers, so the evaluation period is long, and the cost of the sample is also evaluated. It has become huge. Moreover, it is therefore difficult to evaluate a plurality of conditions.

Therefore, a method has been developed in which a plurality of experiments are not performed, but a method of predicting the internal stress of the coil by theory to obtain a winding condition. For example, the winding method of the net described in Patent Document 1 discloses a method in which a theoretical formula is used by introducing a radial equivalent Young's modulus taking into consideration the thickness of the air film interposed between the nets. A radial stress (or surface pressure) that satisfactorily matches the actual value is calculated, and an excellent winding tension pattern is determined such that the radial stress or the traverse resistance reaches a desired value over the winding radius. .

Moreover, Non-Patent Document 1 discloses a formula for calculating the internal stress of a roll.

Prior art literature Patent literature

Patent Document 1: Japanese Patent Special Publication No. 7-33198

Non-patent literature

Non-Patent Document 1: Z. Hakiel, "Non linear model for wound roll stresses", Journal of the Pulp and Paper Industry Technical Association (J.Tech.Assoc. Paper Pulp. Ind.), Vol. 70 (vol. 70), p. 113 - p. 117, issued in 1987

However, in the winding method of the net disclosed in Patent Document 1, since the thickness distribution of the net or the knurling is not considered, there is a problem that the error becomes large and it is not practical. Here, knurling It means a minute uneven portion for preventing slippage formed at both end portions in the width direction of the net.

Here, reference is made to FIG. Fig. 19 is a perspective view of a roll for explaining stress inside the roll. 19, in the internal volume 10, the presence of stress in the radial direction and the circumferential direction of the stress σ _r σ _t, stress σ _r in the radial direction is the radial direction of the roll 10 and the film (film) 31 is applied stress, the The circumferential direction stress σ _t is a stress applied to the film 31 in the circumferential direction of the film 31. As shown in the partial enlarged view 400, the vertical resistance N is obtained by multiplying the radial stress by the area, and the frictional force F = μN when the friction coefficient of the film is μ. Therefore, if the stress in the radial direction is different, the frictional force is also different. Therefore, when the radial direction stress changes in the width direction of the roll, the radial direction stress must be considered. If knurling is formed, the radial stress of the portion will be greatly different. Therefore, when calculating the stress, the calculation cannot be performed using the same model as the portion where the knurling is not formed.

The present invention has been made in view of the above circumstances, and it is intended to provide a web winding manufacturing method and a web winding method which take into consideration the stress variation in the width direction of the web.

The problem of the present invention can be solved by the following inventions.

That is, the method of manufacturing the web roll of the present invention is to manufacture a web roll in which a web is wound on a core, and the main method of manufacturing the web roll includes a dummy roll manufacturing step, use and use. The net of the net roll is wound on the same core, and the net is wound onto the core to prepare a virtual roll for evaluation. In the model making step, a plurality of segmentation models are created, and the segmentation model is Dividing the web roll into a plurality of tangentially in the width direction; calculating steps for each of the segmentation models and for each winding radius, based on the circumferential direction Young's modulus, radial direction, Young's a modulus and a winding tension profile to determine at least one of a circumferential stress and a radial stress; a defect occurrence stress range determining step, which occurs according to the virtual volume in the virtual volume forming step Defect occurrence winding radius, and in the calculation The stress of each winding radius obtained in the step is determined as a defect occurrence stress range in which the defect may occur; a stress recalculation step is performed, and a winding tension pattern as a winding condition is changed, The air press repeats the calculation step by at least one of a pressure pattern, a thickness distribution in a width direction of the film, a height of a knurling portion, and an amplitude of an oscillate. The stress up to the range of the specified winding radius is no longer included in the defect occurrence stress range; and the winding step does not include the stress in the range of the specified winding radius found in the stress recalculation step The winding of the web is performed under the winding conditions within the stress occurrence range of the defect.

Thereby, a model which is divided in the width direction of the web roll is produced, and stress calculation is performed for each of the divided models, so that the stress distribution in the entire width direction of the web roll can be obtained. Therefore, the stress can be accurately recognized, and even if a plurality of defects occur in the production of the virtual volume, it is possible to manufacture a network roll in which a plurality of defects are all solved.

Moreover, the web winding method of the present invention is for forming a web roll in which a web is wound on a core, and the web winding method is mainly characterized by comprising: a virtual roll making step, using and using the web roll a net of the same net, winding the net onto the core, thereby making a virtual volume for evaluation; a model making step of making a plurality of segmentation models, the segmentation model is to roll the web in the width direction Dividing into a plurality of tangentially; calculating steps for each of the segmentation models and for each winding radius, based on the circumferential Young's modulus, the radial Young's modulus, and the winding tension distribution At least one of a directional stress and a radial stress; a defect occurrence stress range determining step of generating a winding radius according to a defect of a defect occurring in the virtual volume in the virtual volume forming step, and seeking in the calculating step The stress of each winding radius is obtained, the stress occurrence range of the defect in which the defect may occur is determined; the stress recalculation step is performed, and the winding tension pattern and the pneumatic pressure as the winding conditions are changed. Pressing force pattern, the film thickness distribution in the width direction, the height of the knurled portion, the wobble amplitude in at least one, repeating the calculation a step until the stress in the range of the specified winding radius is no longer included in the defect occurrence stress range; and the winding step to stress the range of the specified winding radius found in the stress recalculation step The winding of the web is performed without including the winding conditions within the stress occurrence range of the defect.

Thereby, a model which is divided in the width direction of the web roll is produced, and stress calculation is performed for each of the divided models, so that the stress distribution in the entire width direction of the web roll can be obtained. Therefore, the stress can be accurately recognized, and even if a plurality of defects occur in the production of the virtual volume, it is possible to obtain a winding condition in which all of the plurality of defects can be satisfactorily eliminated.

Furthermore, the internal stress calculation method of the present invention is a method for calculating an internal stress of a net wound with a net wound on a core, and the main feature of the internal stress calculation method includes: a calculation model making step, and a plurality of split models are prepared. The segmentation model divides the web roll into a plurality of pieces in a tangential direction in a width direction; and a calculation step for each of the segmentation models and for each winding radius, based on a circumferential direction Young's modulus, a radial direction The Young's modulus and the winding tension distribution are used to determine at least one of the circumferential stress and the radial stress.

It is possible to provide a method of manufacturing a web roll and a method of winding a web which takes into account stress variations in the width direction of the web.

10, 306‧‧ ‧ volumes

11, 12, 13, 14 ‧ ‧ split volumes

18‧‧‧Volume core

21, 22, 23, 24 ‧ ‧ split network

31‧‧‧ Film

32‧‧‧ Air

33‧‧‧ dividing line

34‧‧‧ knurling department

50‧‧‧Pneumatic press device

60‧‧‧ split film

80‧‧‧ step part

302‧‧‧pressure sensor

304‧‧‧ net

400‧‧‧Partial enlargement

A1, a2, a3, a4‧‧‧ thickness

h, ha, ho‧‧‧ thickness of the air layer

L‧‧‧Wound length

r‧‧‧Wound radius

S1, S2, S3, S4, S5‧‧ steps

T, T1, T2, T3, T4‧‧‧ tension

V‧‧‧ winding speed

W1, W2, W3, W4‧‧‧ width

Wa‧‧‧ film full width

σ _r ‧‧‧ Radial stress

σ _t ‧‧‧ circumferential stress

Figure 1 is a conceptual diagram of a three-dimensional model of a volume.

FIG. 2 is an explanatory diagram for explaining each parameter of the divided volume.

3 is a schematic view showing a cross section of two nets in a roll.

4 is a view showing a tension distribution in the width direction of the net.

Fig. 5 is an explanatory view showing a state in which air is trapped between the films.

Fig. 6 is a schematic view showing a part of a winding cross section in a direction parallel to the central axis.

Fig. 7 is a schematic view showing a part of a cross section of a roll in a tangential direction.

8(A), 8(a), 8(B), 8(b), 8(C), and 8(c) are graphs showing stress calculation results and actual measurement values.

Fig. 9 is a flow chart showing the flow of a winding method of a net.

Fig. 10 is a schematic cross-sectional view showing a tangential direction of a roll for slit transfer.

Fig. 11 is a graph showing the relationship between the winding radius and the film tension.

Fig. 12 (a) is a three-dimensional graph showing the relationship between the winding length of the virtual roll and the radial stress. Fig. 12 (b) is a graph showing the relationship between the winding length at the center portion of the shaft of the virtual roll and the radial stress.

Fig. 13 (a) is a three-dimensional graph showing the relationship between the winding radius of the virtual roll and the radial stress. Fig. 13 (b) is a graph showing the relationship between the winding radius of the knurled portion of the virtual roll and the radial stress.

Fig. 14 is a graph showing the relationship between the winding radius and the central radial direction stress under the initial conditions and the derived conditions.

Fig. 15 is a graph showing the relationship between the initial condition and the winding radius - knurl radius stress in the derived condition.

Figure 16 is a graph showing the derived winding radius - film tension conditions.

Fig. 17(A) is a schematic view showing a part of a cross section of a three-dimensional model of a roll. Fig. 17 (B) is a schematic view showing a state in which the knurled portion is close to the lower film in Fig. 17 (A).

Fig. 18(A) is a schematic view showing a part of a cross section of a three-dimensional model of a roll. Fig. 18 (B) is a schematic view showing a part of a cross section of the three-dimensional model in the case where the portion having the largest "film thickness + air film thickness" is close to the lower film in Fig. 18 (A).

Fig. 19 is a perspective view of a roll for explaining stress inside the roll.

Fig. 20 is a view showing a simulation result in a two-dimensional model of the internal stress of the coil.

Fig. 21 is a schematic view showing the arrangement of a pressure sensor in a roll.

Fig. 22 is a view showing measured values of internal stress of the coil.

Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the accompanying drawings. Here, the parts indicated by the same reference numerals are the same elements having the same functions. Further, in the present specification, when "~" is used to indicate a numerical range, the numerical values of the upper limit and the lower limit indicated by "~" are also included in the numerical range.

<Method for calculating the radial stress of the coil inner mesh>

A method of calculating the internal stress of the wound web in the present invention will be described with reference to the drawings.

Existing two-dimensional model

When the internal stress of the web wound into a roll (hereinafter referred to as a roll) is obtained by simulation, it is expected that a high-precision result can be obtained by producing a three-dimensional model in which the mesh is finely cut. However, in the case of simply creating a three-dimensional model, not to mention that in the case of producing a three-dimensional model in which the mesh is finely cut, the calculation becomes very complicated, and the nonlinear ordinary differential equation sometimes cannot be easily solved, even if the solution It is sometimes too time consuming to form an equation for calculating the internal stress of the coil, that is, a winding equation.

Therefore, first, in order to investigate the accuracy of the simulation under the existing two-dimensional model (hereinafter referred to as the existing simulation), the existing simulation is performed, and the simulated value of the internal stress of the volume is compared with the measured value and studied. . The existing simulation is performed based on Non-Patent Document 1. The result is shown in Fig. 20. Fig. 20 is a view showing a simulation result in a two-dimensional model of the internal stress of the coil.

Further, as shown in FIG. 21, the measured values are sandwiched between a plurality of pressure sensors 302 in the middle of winding the net 304, and the pressure is measured by the pressure sensor 302. Figure 21 is a representation A schematic view of the configuration of the pressure sensor within the volume. The pressure sensor 302 is provided in the roll 306 at a predetermined width direction for each predetermined winding radius. The measurement result of the pressure sensor 302 is shown in FIG. Fig. 22 is a view showing measured values of internal stress of the coil.

Referring to Fig. 20, since it is a two-dimensional model (a model of a section in which a loop is cut), the influence of the width direction of the roll (the presence or absence of knurling, the thickness distribution of the web in the width direction) is not considered, at any winding radius. The radial direction stress in the width direction is fixed. Here, the radial stress refers to the radial stress of the mesh. Hereinafter, it is also referred to as a radial direction stress.

On the other hand, referring to Fig. 22 showing the actual measurement value, the radial stress at both end portions in the width direction of the knurled roll is increased. It is thus found that the two-dimensional model does not correctly represent the actual stress.

(2) Three-dimensional model used in the present invention Summary of 3D models

In the present invention, a three-dimensional model is created in order to improve the inaccuracy of the existing two-dimensional model. The three-dimensional model is produced by dividing a roll 10 wound with a net (ribbon flexible support) into a plurality of pieces in a width direction and discretizing as shown in FIG. (discretize). Here, the circumscribed section of the roll is originally spiral, but a concentric shape model is produced in the three-dimensional model of the present invention. Figure 1 is a conceptual diagram of a three-dimensional model of a volume.

Next, the three-dimensional model used in the present invention will be described in more detail with reference to the accompanying drawings. FIG. 2 is an explanatory diagram for explaining each parameter of the divided volume. 3 is a schematic view showing a cross section of two nets in a roll. 4 is a view showing a tension distribution in the width direction of the net.

As shown in Fig. 2, the three-dimensional model used in the present invention is a roll 10 in which a web (also referred to as a film) is wound on a core 18 by a width W1, W2, W3, W4 (hereinafter omitted). The division is performed to form a divided volume (also referred to as a division model) 11, a divided volume 12, a divided volume 13, and a divided volume 14 (hereinafter omitted). Here, in the present description, only the four divisions of W1 to W4 are explicitly described, but this is only for convenience of explanation, and is divided into four divisions as an example, and is not limited to four points. By cutting, it is possible to create a model of an arbitrary number of divisions based on the form of the volume of the simulation target and the accuracy to be obtained.

It is considered that the divided volumes 11, 12, 13, 14 (hereinafter omitted) are volumes in which the divided nets 21, 22, 23, 24 (hereinafter omitted) are respectively wound, and the divided nets 21, 22, 23, 24 are considered. The tensions (hereinafter omitted) are the tensions T1, T2, T3, and T4 (hereinafter omitted). It is considered that the thicknesses of the divided nets 21, 22, 23, 24 (hereinafter omitted) are a1, a2, a3, and a4, respectively.

Further, as a parameter common to each of the divided rolls 11, 12, 13, 14, ... (hereinafter omitted), the winding speed V, the winding length L, the film full width Wa, and the winding radius r are considered. The winding speed V refers to the speed at which the web is wound. The winding length L refers to the length of the wound web. The full width Wa of the film means the full width of the mesh, that is, W1 + W2 + W3 + W4 + ... (hereinafter omitted) (in addition, the film and the mesh are used in the same meaning below). The winding radius r is the radius of the roll.

Here, when the stress analysis is performed using the three-dimensional model, there is a problem that the calculation becomes very complicated, and the equation of the nonlinear shape called the winding equation cannot be easily solved. However, the inventors' intensive research found that the winding equation of the three-dimensional model can be solved by considering the connection conditions between the split rolls, that is, the width direction stress and the displacement connection condition, and the obtained value becomes close to the experiment. The value of the value. That is, by simply unwinding the winding equation for each divided volume to obtain the stress, the stress value close to the experimental value can be easily obtained.

Next, description will be made with reference to FIG. 3. 3 is a schematic view showing a cross section parallel to a central axis of rotation of two films (webs) which are superposed in a roll. As shown in FIG. 3, the thickness of the film (mesh) 31 is mostly thin at the center, and the thicker the outer layer is formed, the thickness is formed (not limited thereto). Moreover, there is air entrapped between the films 31. The interval at which the roll 10 is divided into the dividing lines 33 of the divided rolls is wider as it goes toward the center portion, and becomes narrower as it goes toward both end portions.

As a result, the portion where the thickness changes greatly, in particular, the both end portions where the knurling portion 34 is formed to have a large thickness change, the finer the division is performed, and the calculation result of the stress can be made close to the experimental value.

Next, description will be made with reference to Fig. 4 . 4 is a view showing the relationship between the position in the width direction of the film and the tension. The horizontal axis of Fig. 4 indicates the position in the width direction of the film, and the vertical axis indicates the tension of the film. Referring to Fig. 3 together with Fig. 4, as shown in Fig. 4, the tension is set so that the tension becomes larger in proportion to the thickness of the film. The reason for this is that the thicker the film thickness (divided roll), the greater the tension that is received. The film tension is divided for each of the divided rolls in each of the divided rolls so that the tension of the film is reached if the tension of all the areas (all divided rolls) is totaled.

Specifically, when the thickness of the film of each divided roll is t _n (m), the tension applied to the full width of the film is T (N), and the sectional area of the full width of the film is A (m ² ). Then, the tension per unit sectional area is T/A (N/m ² ). When T/A is multiplied by the thickness of the film of each divided roll, the tension Tn per unit width of each divided roll can be calculated as Tn=[T×t _n /A](N/m).

(2) Calculation of the thickness (air film thickness) of the air layer interposed between the films

Next, a calculation method of the thickness of the air layer in which the air entrained between the film and the film forms an air layer between the films during winding of the film to form a roll will be described with reference to the drawings. Fig. 5 is an explanatory view showing a state in which air is caught between the films. FIG. 5 shows an outline of a cross section of the roll 10 around which the film 31 is wound. The thickness of the air that was caught between the films was calculated using the foil bearing theory as shown below.

As shown in FIG. 5, the film 31 is conveyed in the direction of the arrow and wound onto the roll 10. At this time, the air is taken up between the outermost film (the uppermost film in the drawing) and the film under the film, and the thickness of the air layer at this time is set to ho.

In order to remove the entrapped air, that is, to reduce the thickness of the air layer (air film thickness) ho, air is blown from the pneumatic press device 50 to the outermost film surface to press the outermost film to The entrapped air is extruded (the effect of treating air as non-compressible and extruding air from between the films to the outside of the roll is called a non-compressible squeezing function). The thickness of the air layer to be pressed by the pneumatic press device 50 (empty The film thickness) is set to ha.

Here, the case where the pneumatic press device 50 is used in order to achieve a squeezing effect will be described as an example, but not only a pneumatic press device but also a device capable of applying pressure to the surface of the film may be used. The thickness calculation of the air layer can also be performed in the same manner by using various devices such as a contact roll.

Further, the thickness of the air layer at the time of h is set to h, that is, the film is wound onto the roll 10, and the multilayer film is wound on the outer side of the film, whereby the stress of the film (perpendicular to the film surface) The stress in the direction), and the same pressing action (extrusion) is performed on the entrapped internal air. The calculation method of ho, ha, and h will be described below.

The thickness ho of the air layer flowing in during winding is obtained by the following formula 1.

Here, R, η, Vr, Vw, and T are represented below.

R: radius of volume 10

η: viscosity coefficient of air

Vr: rotation speed of the roll (linear velocity outside the roll)

Vw: conveying speed of the wound film

T: film tension

Next, using the calculated ho, the thickness ha of the air layer which is started to be wound by the pneumatic press device 50 is obtained by the following formula 2.

Here, L, W, and t are represented below.

L: force of pressing the film wound on the roll 10 to the roll 10 by the air ejected from the pneumatic press device 50

W: the width of the net

t: time

(3) Application to the model of the entrapped air layer

Next, a model of the thickness h of the air layer after being wound (inside the winding) will be described with reference to FIGS. 6 , 17 (A), 17 (B), 18 (A), and 18 (B). Be applicable. Fig. 6 is a schematic view showing a part of a winding cross section in a direction parallel to the central axis. Figure 17 (A) is a schematic view showing a part of a cross section of a three-dimensional model in which no other film having "film thickness + air film thickness" is present, the film thickness including the knurled portion is The overall thickness inside is large. Fig. 17 (B) is a schematic view showing a state in which the knurled portion is close to the lower film in Fig. 17 (A). Fig. 18(A) is a schematic view showing a part of a cross section of a three-dimensional model in which another film having "film thickness + air film thickness" is present, which is a film thickness including a knurled portion. The overall thickness is large. Fig. 18 (B) is a schematic view showing a part of a cross section of the three-dimensional model in the case where the portion having the largest "film thickness + air film thickness" is close to the lower film in Fig. 18 (A).

In the present invention, it is considered that the film is a rigid body. Moreover, for the surface and back of the film, The surface on the center side of the roll is the surface, and the surface on the outer side of the roll is the back surface. Here, as shown in FIG. 6, the film 31 is formed as an example, and the film 31 is formed so that the thickness of the film becomes thicker from the center portion toward both end portions. However, the present invention is not limited to the thickness pattern shown by the film 31, and the present invention can be applied regardless of the thickness pattern, and is within the scope of the invention.

In the case of a film having a thickness distribution, it is assumed that the upper and lower films are to be in contact with the upper portion of the thicker portion in the width direction (to be close). If, as shown in Fig. 17(A), there is no other film 60 having a value of "thin film thickness + air film thickness ha" (referred to as division film 60 for short), the film thickness + air film thickness The value of "ha" is larger than the maximum film thickness of the film thickness of each of the divided rolls when the knurled portion 34 is also a part of the film, and the knurled portion 34 is not subjected to the roll as shown in Fig. 17(B). The air is impeded and squeezed, and as a result, the interval between the upper and lower films is determined, and the air film thickness of other regions is also determined.

For winding the air film between the layers, at this time, the air film thickness h under the knurling portion 34 (or the film having the largest film thickness among the divided films 60) is obtained by the following formula 3A or formula 3B. As shown in Fig. 6 and Fig. 17(B), it is considered that the air film thickness under the divided film 60 is equal to the interval between the surface of the divided film and the back surface of the film which is formed by the film thickness distribution.

Can also be easily exported from Boyle's law instead of Equation 3A. The following formula 3B.

σ: Radius stress (calculation result when Hakiel is wound up to the i-th layer)

σ ₀ : initial radial direction stress (calculation result when Hakiel is wound up to the i-1th layer)

P _ap : atmospheric pressure

Ha: thickness of the air layer after being pressed by a pneumatic press by a force of L in the radial direction. After the entrapment, the thickness h of the entrapped air layer when Hakiel is wound up to the i-1th layer.

As shown in Fig. 18(A), there is a divided film 60 having a value of "thin film thickness + air film thickness ha" which is also a film than the knurling portion 34 in consideration of the knurling portion 34. When the film thickness of the film having the largest film thickness in the film of the split model is large, as shown in FIG. 18(B), the air entrapped in the other ring-cut regions may be hindered and difficult to be extruded. The interval between the air and the upper and lower films is determined as follows.

There are two methods, (1) as shown in Fig. 18(B), the portion of the film other than the knurled portion, "thin film thickness + air film thickness ha" is the largest split film and the film under the split film is air. When the film thickness ha is arranged at intervals, the distance between the upper and lower divided films (the distance between the surface of the upper film and the back surface of the lower film) is taken as the air film thickness.

Or (2) the total area of the cross-sectional area of the entrapped air of each of the divided films shown in FIG. 18(B) and the cross-sectional area of the gap between the upper and lower films (between the surface of the upper film and the back surface of the lower film) are obtained. The distance between the upper surface of the upper film and the surface of the lower film is defined as the air film thickness at which the distance between the upper and lower divided films at this time (the distance between the surface of the upper film and the back surface of the lower film).

As described above, it is preferable to perform the comparison of the film thicknesses in the width direction for the accuracy of the calculation. However, it is also possible to perform the roll-in extrusion using the formula 3A or the formula 3B over the entire width direction without performing the film thickness comparison. Calculate and calculate h as the thickness of the air film (in the case of no knurling or when the knurling is low and the influence is small).

In this way, by considering the thickness of the air to be entrained, the influence of the entrapped air can be numerically analyzed with ease and accuracy, and the stress distribution in the width direction of the roll can be accurately calculated.

(4) Swing in the width direction

The wobble in the width direction (hereinafter referred to as wobble) means that when the film is wound to form a roll, the wound film is reciprocally moved in the width direction of the film with respect to the roll during winding of the film.

A method of applying the wobble to a model will be described with reference to FIG. Fig. 7 is a schematic view showing a part of a cross section of a roll in a tangential direction. Part (A) of Fig. 7 shows a case where the amplitude of the wobble is 10 mm, and part (B) of Fig. 7 shows a case where the amplitude of the wobble is 5 mm. Here, the amplitude refers to a distance that moves in the width direction by swinging. Further, in FIG. 7, the range enclosed by the broken line can be considered as, for example, the range of one divided volume divided in the three-dimensional model.

At this time, the portion in which the knurled portion 34 is formed is in the range of the broken line, and the case where the amplitude is 5 mm is more than the case where the amplitude is 10 mm. This means that the stress in the radial direction becomes large. In consideration of the influence of such a wobble, for example, in the case where the film of the divided roll B adjacent to the range of the divided roll A and the air layer are invaded by the wobble, the length of the intrusion portion and the film of the original divided roll A and The length of the air layer is proportionally distributed to calculate the equivalent film thickness and the equivalent air layer thickness.

At this time, both the film thickness and the air layer thickness were calculated. Thereby, the influence of the swing can also be fully considered. Here, the oscillating means that the film is swayed in the width direction at a fixed period, and The cycle has a winding length cycle and a winding radius cycle. The winding length period refers to the winding length when one reciprocating swing is performed for each fixed winding length. Further, the winding radius period refers to an increment of the winding diameter when one reciprocating swing is performed each time the winding diameter is increased by a fixed length. Regardless of the period of the cycle, by applying the above method, the calculation can be performed in consideration of the influence of the wobble.

(3) Calculation of the radial stress and the circumferential stress of the net

According to the model described so far, the modified Hakiel model (modified Hakiel model) is taken into consideration for the air film between the films to be entrained (see Non-Patent Document 1). The solution is performed to obtain the radial direction stress σ _r and the circumferential direction stress σ _t .

Here, r, E _t , and E _r are represented below.

r: winding radius

E _t : circumferential Young's modulus

E _r : Young's modulus in the radial direction

Further, the radial direction is the Young's modulus E _r by the following equation 6 is obtained.

Tw: thickness of the net

h: air layer thickness

E1: Young's modulus in the radial direction of the net

E2: Young's modulus in the radial direction of the air layer

Here, Et is a physical property value obtained by an ordinary tensile test method. The web was stretched in the circumferential direction (tangential direction) to measure deformation and stress. Deformation - The slope of the circumferential direction stress becomes Et.

Moreover, the radial Young's modulus E1 of the net is known by the well-known K2 factor test (established by JDPfeiffer in the Tappi Journal). The physical property value obtained by performing the compression test of the stack in the radial direction. The radial Young's modulus E1 of the mesh is obtained from the strain at the time of applying the compressive load and the slope of the radial stress.

(4) Calculated value and measured value of the radial stress of the net

Next, the evaluation of the calculated value and the measured value obtained by the calculation method of the radial direction stress of the net of the present invention will be described in detail with reference to the drawings. 8(A), 8(a), 8(B), 8(b), 8(C), and 8(c) are graphs showing stress calculation results and actual measurement values.

The stress in the radial direction is calculated by a computer according to the following conditions 1 to 3. At this time, the film was actually wound according to Conditions 1 to 3, and as shown in Fig. 21, a stress sensor was used to measure the radial stress.

. Condition 1: Thickness distribution of film with a swing amplitude of 5 mm, a tension of 580 N, a knurled thickness of 8 μm, and a width of 79.0 μm to 81.5 μm

. Condition 2: Thickness distribution of film with a swing amplitude of 10 mm, a tension of 580 N, a knurled thickness of 8 μm, and a width of 79.0 μm to 81.5 μm

. Condition 3: Film thickness distribution of 0 mm (no wobble), tension 580 N, knurled thickness 8 μm, width direction 79.0 μm to 81.5 μm

The stress calculation results at the conditions 1 to 3 are as shown in Fig. 8 (A), Fig. 8 (B), and Fig. 8 (C), respectively. Further, the measured values at the conditions 1 to 3 are as shown in Fig. 8 (a), Fig. 8 (b), and Fig. 8 (c), respectively.

Comparing Fig. 8(A) with Fig. 8(a), it can be seen that the calculated value is very close to the measured value. In particular, the change in the radial stress caused by the influence of the knurl at both ends in the width direction of the film is also calculated to be close to the measured value.

Similarly to FIG. 8(B), FIG. 8(b), FIG. 8(C) and FIG. 8(c), it is understood that the value close to the actual measurement value can be calculated by calculation even if the condition is changed. That is, by using the stress calculation method of the present invention, it is possible to obtain a value close to the actual measurement value.

<Web winding method using radial stress in the coil inner mesh>

Next, a method of winding a web using the radial stress and the circumferential stress of the in-web obtained by the above method will be described with reference to the drawings. Fig. 9 is a flow chart showing the flow of a winding method of a net.

8(A), 8(a), 8(B), 8(b), 8(C), and 8(c), first, a virtual volume (S1: Virtual volume production step). The virtual roll is produced by winding a film (web) identical to the film (web) used in the article onto the core. However, the conditions for winding may be appropriate. Here, the conditions for winding refer to a winding tension distribution, a swing amplitude, a knurl height, a mesh thickness pattern, and the like.

The winding tension distribution is a pattern of change in winding tension from the start of winding to the end of winding. The wobble amplitude refers to the width of movement caused by the wobble. The knurl height refers to the height from the surface of the web from which knurling is not formed to the apex of the convex portion due to knurl formation. The net thickness pattern refers to a change pattern of the thickness in the width direction of the net.

Before or after S1 or at the same time, a segmentation model is created by the above method, which divides the roll into a plurality of pieces in a width direction (model making step), using the same as the product (ie, with the virtual volume) The same direction of the circumferential Young's modulus and the radial Young's modulus are used to solve Equation 4 and Equation 5, so that for each winding radius and for each segmentation model, the radial stress and circumferential direction of the virtual volume are obtained. Stress (S2: calculation step). In addition, when it is described below as stress calculation, all refer to the radial direction stress calculation or the circumferential direction stress calculation by the above method.

Next, the ultimate stress evaluation is performed (S3: ultimate stress determining step). The ultimate stress evaluation refers to an evaluation as described below, that is, various defects occurring when making a virtual volume, that is, winding misalignment, cut edge transfer, recess, black belt, volume Winding crinkle, chrysanthemum-like marking, etc., are investigated in the number of meters from the core side (in other words, the winding radius is a few millimeters), and are investigated in S2. The stress calculation result is obtained by obtaining the radial direction stress σ _r and the circumferential direction stress σ _t at this time. Various defects will be described below.

Volume misalignment

The roll misalignment defect refers to a state in which the position of both side ends of the roll in which the net is wound is a state deviated from a position which is a state after the completion of the roll, that is, a position of the initial state. For the countermeasure against this defect, the radial direction stress σ _r must be increased.

(2) Incision transfer

The kerf transfer means: as shown in Fig. 8(A), Fig. 8(a), Fig. 8(B), Fig. 8(b), Fig. 8(C), Fig. 8(c), if it is on the core When the film is wound on the step portion 80 of the unwinding which is generated when the film 31 is wound up, a step is also generated on the film which is wound. For the countermeasure against this defect, the radial direction stress σ _r must be lowered. Fig. 10 is a schematic cross-sectional view showing a tangential direction of a roll for slit transfer. A step is inevitably generated in the winding portion, and the step due to the influence of the step becomes smaller as the film winding progresses, and finally reaches a level below the no-form problem. When the winding length of the film is as short as possible in the level of the product-free problem as described above, it is preferable because a large amount of the product can be obtained in a large amount.

(3) daisy pattern

The compositive pattern refers to a defect in which the film is buckling due to compression in the circumferential direction and the film is undulated. If viewed from the end face side of the roll, the defect looks like a velvet pattern. For the countermeasure against this defect, if the circumferential direction stress σ _t is negative, the circumferential direction stress σ _{t is} adjusted to be close to a positive value as much as possible so that the circumferential direction stress σ _t is not compressed (negative).

(4) Concave. Deformation

Concave. Deformation of the depression refers to the following defects: the net is in the recess. The surface of the depressed deformation roll is trapped and deformed by depression. For the countermeasure against this defect, the thickness of the entrapped air film must be reduced.

(5) Black belt

When the film is wound, sometimes the convex portions of the film may coincide at the same position. At this time, as the roll is plunged, a strong pressure is applied to the portion of the convex portion, thereby causing the portion to adhere, or the pressure is extended, thereby deteriorating the quality of the product. Moreover, if the portion is viewed from the outside, it looks like a black band. This is the black belt defect. For the countermeasure against this defect, the amplitude of the wobble must be increased, or the radial stress σ _r must be lowered.

(6) wrinkle

The wrinkle defect refers to a defect in which wrinkles are generated when the film is wound. For the countermeasure against this defect, the circumferential direction stress σ _t must be lowered.

Next, in order to determine the defect occurring in the virtual volume within a predetermined range of the winding radius (the range of the winding radius in which the defect should not occur in the specification of the product is referred to as the range of the predetermined winding radius) The rewinding conditions that occur again are as follows. In other words, the radial stress at the time of the occurrence of the defect, the radial stress as the defect in the circumferential direction, and the circumferential stress in the defect are obtained, and the stress range in which the defect may occur is determined as the defect occurrence stress range (defect occurrence stress range determining step). . Specifically, it is as follows.

. In the case of a roll misalignment defect, the stress range below the radial stress of the defect is the defect occurrence stress range.

. In the case of a kerf transfer defect, the stress range above the radial stress of the defect is the defect occurrence stress range.

. In the case of a garnet pattern defect, the stress range below which the defect occurs in the circumferential direction stress is the defect occurrence stress range.

. In the case of a recess defect, the film thickness range in which the defect occurs above the thickness of the air film is a range in which the defect occurs in the film thickness.

. In the case of a black strip defect, the stress range above the radial direction stress of the defect is the defect occurrence stress range.

. In the case of a wrinkle defect, the stress range in which the defect is less than or equal to the circumferential direction stress is the defect occurrence stress range.

Next, a stress that does not occur within a predetermined winding radius, that is, a stress within a predetermined winding radius (radial stress, circumferential stress) is no longer included in the defect occurrence stress range. In the inner method, the stress calculation is performed by changing at least one of the winding tension pattern as the winding condition, the thickness distribution in the width direction of the film, the height of the knurled portion, and the amplitude of the swing (S4: stress recalculation step). The stress calculation is to change the winding conditions. Repeatedly until the winding condition in which the defect does not occur within the range of the predetermined winding radius is obtained (the winding stress in the range of the predetermined winding radius is no longer included in the winding stress range) until. Thereby, it is possible to derive the stress in the range of the predetermined winding radius without including the winding condition within the defect occurrence stress range.

The web of the article can be manufactured by winding the film (web) on the winding core using the derived winding conditions.

Here, the winding tension pattern refers to a pattern of change in film tension at the time of winding in accordance with the winding radius at the time of film winding as shown in FIG. 10 . Fig. 11 is a graph showing the relationship between the winding radius and the film tension.

Finally, the film is actually wound in accordance with the obtained winding conditions (S5).

In this way, the calculation of the winding conditions by the stress inside the roll of the three-dimensional model is performed, and the winding condition in which the defect does not occur can be obtained, and the actual evaluation is hardly performed. These stress calculations and the operation for determining the winding conditions can be performed using a computer. By causing the computer to execute the above calculation formula and calculation flow, stress calculation and graphing can be performed by inputting the winding condition.

<evaluation>

Next, for the winding method of the present invention, two kinds of optical films of the variety A and the variety B were evaluated.

Variety A evaluation

First, a virtual roll of the variety A was produced, and the virtual roll of the variety A was slit-transformed before the winding length of 100 m, and the roll misalignment occurred at the portion of the roll diameter of φ520 mm. The winding conditions at this time are as follows.

. The winding tension is 650 N, the winding tension is 580 N, and the tension changes linearly from the winding to the end of the winding.

. The knurling height is 6 μm (the thickness of the knurled part is obtained by adding the thickness of the film to the height of the knurling of 6 μm)

. Swing amplitude 10 mm

Therefore, based on the production conditions of the virtual volume, the stress calculation method of the present invention determines the change in the radial stress when the winding length and the winding radius of the film are changed. The results are shown in Fig. 12 (a), Fig. 12 (b), Fig. 13 (a), and Fig. 13 (b).

Fig. 12 (a) is a three-dimensional graph showing the relationship between the winding length of the virtual roll and the radial stress. Fig. 12 (b) is a graph showing the relationship between the winding length at the center portion of the shaft of the virtual roll and the radial stress. Fig. 13 (a) is a three-dimensional graph showing the relationship between the winding radius of the virtual roll and the radial stress. Fig. 13 (b) is a graph showing the relationship between the winding radius of the knurled portion of the virtual roll and the radial stress.

The larger the stress of the effective product portion (outside the both end portions of the roll), the more likely the slit transfer defect occurs. Therefore, Fig. 12(b) is a graph in which the effective product portion is represented by the effective product portion in the width direction, and the horizontal axis is the winding length (m) and the vertical axis is the radial stress.

Referring to Fig. 12(b), the kerf transfer defect occurs at a winding length of 100 m. Therefore, if the radial stress at a winding length of 100 m is read (calculated by calculation) from the graph (solid line), 0.088 MPa.

Therefore, if the winding length of the slit defect is, for example, 30 m or less as the target value, the radius is obtained only when the winding length is 30 m or less as shown by the broken line in Fig. 12(b). The value of the directional stress is equal to or higher than the radial stress at which the slit defect does not occur, and may be wound according to the conditions. Here, the target value may be selected according to the product, and the above value is an example, and the present invention is not limited to this value.

Moreover, one of the purposes of forming the knurled portion is to add by the convex portion of the knurled portion. Stress in the direction of the large radius, thereby increasing the friction to prevent the rolls from being misaligned. Therefore, for roll misalignment, the key is to investigate the radial stress of the knurled portion.

Therefore, the graph in which the radial stress at both ends (the knurled portion) in the width direction of the winding as shown in Fig. 13(a) is the vertical axis and the winding radius (mm) is the horizontal axis is shown in Fig. 13(b). The solid line. Since the roll misalignment occurred at a roll diameter of 520 mm, the radial stress at the time of the roll misalignment was calculated from the graph of the solid line (calculated by calculation), and was 0.15 MPa.

In order to make the winding radius at which the roll misalignment occurs, for example, to reach 93.5% of the total winding radius as the target value, that is, 575 mm or more, as long as the broken line of FIG. 13(b) is obtained, only the winding radius is larger than 575 mm. In the case of a winding condition in which the radial direction stress is less than 0.15 MPa, it may be wound according to the conditions. Here, the target value of the winding radius at which the roll misalignment occurs may be an arbitrary % value depending on the product, and the above values are examples, and the present invention is not limited to this value.

Here, the one-dot chain line in FIG. 13(b) indicates the stress of the knurled portion when the condition of the broken line in FIG. 12(b) is satisfied. That is, it can be seen that if the winding tension is changed in order to cope with the slit defect to reach the radial stress shown by the broken line in Fig. 12(b), although the slit defect is alleviated, the point chain as shown in Fig. 13(b) As shown by the line, the volume misalignment defect will deteriorate.

Thus, changing the winding tension to alleviate the gap defects and the roll misalignment defects is in a trade off relationship with each other, and if one is good, the other will deteriorate. Therefore, the notch defect is dealt with by changing the winding tension, and the roll misalignment defect is changed by changing the swing width. This is because even if the winding tension is not changed, the radial stress of the knurled portion changes as long as the swing width is changed.

In this way, in order to prevent the notch defect, the winding tension is changed, and the wobble width is changed in order to prevent the roll misalignment defect. In this case, a total of 100 or more simulations are performed to derive a roll capable of simultaneously preventing the notch defect and the roll misalignment defect. Around the conditions. The results are shown in Fig. 14 and Fig. 15.

Figure 14 is a view showing the winding radius at the initial condition and the derived condition - the radial direction of the center portion A chart of the relationship of stress. Fig. 15 is a graph showing the relationship between the initial condition and the winding radius - knurling radius stress in the derived condition. The broken line in Fig. 14 indicates the winding result under the initial condition that the tension is linearly changed from the winding tension 650 N to the winding tension 580 N and the knurling amplitude is 10 mm. Further, the solid line in Fig. 14 indicates a newly derived condition, that is, a winding result in which the tension is linearly changed from the winding tension 550 N to the winding end tension 550 N, and the swing amplitude is 5 mm.

Further, the broken line in Fig. 15 indicates the winding result under the initial conditions similar to the broken line in Fig. 14, and the solid line in Fig. 15 indicates the winding result under the newly derived condition similar to the solid line in Fig. 14. As shown in FIGS. 14 and 15, by changing the tension and the knurling amplitude, the radial stress in the central portion of the roll can be reduced, and the radial stress of the knurled portion can be increased. As a result, both the kerf transfer defect and the roll misalignment defect were successfully optimized at the same time.

Thus, according to the present invention, it is possible to derive a defect-free winding condition using a simulation that is inexpensive and time-consuming.

(2) Evaluation of variety B

Next, the evaluation of the variety B will be described. Similarly to the variety A, the cultivar B was produced as a virtual roll, and the diameter range of the roll in which the slit defect occurred and the roll diameter in which the roll misalignment defect occurred were evaluated. Next, the simulation (stress calculation of the present invention) is repeated to derive the winding conditions for optimizing the defects.

Here, the variety B is different from the variety A, and is a variety in which the swing amplitude cannot be changed in the design of the product. Therefore, the winding conditions described below are obtained, that is, only the winding tension of the film is changed to optimize the winding conditions of both the slit defect and the roll misalignment defect.

The result is shown in Fig. 16. Figure 16 is a graph showing the derived winding radius - film tension conditions. The broken line in Fig. 16 indicates the initial condition, and the solid line indicates the newly derived winding condition.

As shown in Fig. 16, the newly derived condition is that the tension is linearly increased each time it is wound up from the start of winding, and then the tension is linearly lowered. By adopting such a winding tension distribution, Even if the knurl amplitude is not changed, for the tension, both the notch defect and the roll misalignment defect in the trade-off relationship can be optimized.

This is considered because the slit defect occurs in the vicinity of the unwinding, so that the tension of the unwinding is reduced as compared with the initial condition, and the tension is increased compared with the initial condition shortly after the winding of the unaligned roll occurs.

However, there are innumerable types of winding conditions for winding radius and tension, and it is practically impossible to derive which conditions are appropriate by the conventional evaluation. According to the method of the present invention, not only the derivation of the existing impossible winding condition distribution is made possible, but also the cost and evaluation are evaluated. The experimental time can also be greatly reduced. For example, in the winding condition derivation of the above-described varieties A and B, the evaluation time can be reduced to about 1/6 of the conventional one (from 300 hours to 50 hours).

The results summarized for the conventional winding conditions and the winding conditions derived in the present invention, including the winding quality, are shown in Table 1. Table 1 is a table summarizing the existing conditions and the derived conditions and the winding quality.

In Table 1, the multi-point tension pattern refers to the slope when the tension pattern is linearly changed. A graphic that changes multiple times in the middle (becomes a broken line). The conventional type of film thickness pattern refers to a pattern in which the central portion in the width direction is thin and both ends are thick, and flat means that the thickness is fixed in the width direction.

Further, the failure evaluation level of each winding quality is shown below.

. Roll misalignment The alignment or disorder of the end face (side) of the wound roll was evaluated.

Excellent: There is no deviation in the width direction and it is beautifully rolled. (within a deviation of less than 3 mm)

Good: You can see the deviation in the width direction. (3 mm~10 mm)

Poor: A portion where there is a large deviation in the width direction.

. The slit is transferred and the step of the winding is transferred to the rolled film to deform.

Excellent: No incision transfer can be seen from the core of 15 m or more.

Good: The incision transfer is weakly seen from the core of 15 m or more.

Poor: The incision transfer is clearly seen from the core of 15 m or more.

. The black belt, also referred to as blocking, refers to a portion in which the film layer and the film layer are in close contact with each other in the winding roll, and as a result, they are adhered together to have a transparent appearance. In the case where the stress in the winding radial direction is large, the black belt is deteriorated. The black belt is in a state of being completely entangled in the air layer.

Excellent: You can't see the black belt.

Good: I saw a little black belt.

Poor: A black band occurs on almost the entire surface of the roll.

. The wrinkle (cross wrinkle) web is compressed in the circumferential direction, and as a result, wrinkle deformation failure occurs in a direction parallel to the winding axis.

Excellent: Can't see wrinkles.

Good: I saw a weak wrinkle.

Poor: Obvious wrinkles that are deformed when the net is bent.

. The surface of the roll is trapped, but it is not a beautiful curve with a circular cross section. The rate, but the failure of the angular deformation of the corner is seen everywhere.

Excellent: no angular deformation is visible on the surface of the roll.

Good: We see weak angular deformation on the surface of the roll.

Poor: Obvious angular distortion is seen over a wide range of surfaces of the roll.

As shown in Table 1, the winding was carried out in accordance with the winding conditions derived by the present invention, whereby a defect-free roll having a good winding quality can be produced.

Further, in the above evaluation, the evaluation for reducing the defect is described by taking the roll misalignment defect and the slit defect as an example. However, in the present invention, the defect is not limited to the volume. Any defects such as misalignment, slit transfer, black belt, wrinkles, dents/edges, etc., become good winding conditions.

This is because, regardless of the defect, it can be improved by conditionally finding any of the radial direction stress, the circumferential direction stress, and the entrapped air film, and can be simulated for use in the present invention. Good winding conditions.

10‧‧‧Volume

Claims (12)

A method of manufacturing a web roll, manufacturing a web roll having a web wound on a core, the method of manufacturing the web roll comprising: a virtual roll making step using the same net as the net for the net roll, Winding the web onto the core to prepare a virtual volume for evaluation; calculating a model making step to create a plurality of split models, the split model is to circumscribe the web roll in a width direction a plurality of calculation steps for determining the circumferential direction stress and the radial direction for each of the segmentation models and for each winding radius based on the circumferential Young's modulus, the radial Young's modulus, and the winding tension distribution At least one stress in the stress; a defect occurrence stress range determining step, a winding radius generated according to a defect of the defect occurring in the virtual volume in the virtual volume forming step, and each obtained in the calculating step The stress of the winding radius, the stress occurrence range of the defect where the defect may occur, the stress recalculation step, the winding tension pattern as the winding condition, and the pneumatic press press The calculation step is repeated for at least one of a force pattern, a thickness distribution of the film in the width direction, a height of the knurled portion, an amplitude of the oscillation, and a period until the stress in the range of the prescribed winding radius is no longer included in the a defect occurring within a stress range; and a winding step, wherein the stress in a range of the predetermined winding radius obtained in the stress recalculation step is not included in the winding within the defect occurrence stress range Conditioning, the winding of the web is performed. The method of manufacturing a web roll according to claim 1, wherein in the calculating step, σ _r as the radial direction stress is a modified Hachier by taking into consideration the entrapment of the air film. The following formula is derived to find out, r: winding radius Et: circumferential direction Young's modulus Er: radial Young's modulus, σ _t as the circumferential direction stress is the correction by taking the air film into consideration The following formula derived by Chir, is obtained. The method for manufacturing a web according to claim 2, wherein when the thickness of the entrapped air film is obtained, the outermost air film thickness ho of the web is obtained by the following formula 1: R: radius η of the web roll: viscosity coefficient of air Vr: rotation speed of the web roll (line speed outside the web roll) Vw: transport speed T of the wound film: proportional to the film thickness of the split model The value of the tension of the entire film is distributed to the tension of each of the divided models. Using the ho obtained in the formula 1, the air film thickness ha is obtained by the following formula 2, and the air film thickness ha is throughout Pressing a part of the outermost mesh with a force of L in the width direction in the width direction to reduce the thickness of the air film after the outermost air thickness, L: force to press the film to the web W: width of the web roll If there is no film of another split model having a value of "thin film thickness + air film thickness ha", the film thickness + air film thickness ha The value is larger than the film thickness of the film having the largest film thickness in the film of the split model when the knurl is also a part of the film, and is obtained by the following formula 3A or formula 3B. The air film thickness h under the film of the maximum film thickness, and for the air film thickness under the film other than the film having the maximum film thickness, considering that the film is a rigid body and the film thickness distribution is The spacing between the surface of the film and the back side of the film below the film serves as the thickness of the entrapped air film, σ: Radius stress (calculation result when Hachil is wound up to the i-th layer) σ ₀ : Initial radial direction stress (calculation result when Hatchel is wound up to the i-1th layer) P _ap : Atmospheric pressure Ha: the thickness of the air film pressed by the pneumatic press with a force of L in the radial direction, and the thickness of the air film h that is entrapped when Hucker is rolled up to the i-1th layer, if present, if present The film of the other divided model having the value of the "thin film thickness + air film thickness ha", the value of the "thin film thickness + air film thickness ha" is larger than when the knurling is also a part of the film In the film of the split model, the film thickness of the film having the largest film thickness is large, and the size of the film film thickness + air film thickness ha of the portion other than the knurled portion is considered to be a rigid body. When the largest split film and the film under the split film are disposed at intervals of the air film thickness ha, the distance between the surface of each upper film and the back surface of the lower film is taken as the thickness of the entrapped air film, or Find the combination of the cross-sectional areas of the entrained air in each segmentation model The cross-sectional area of the gap between the area of the upper film and the back surface of the lower film is the same as the distance between the upper film surface and the lower film surface, and the distance between the surface of each of the upper films and the back surface of the lower film at this time is taken as The thickness of the air film is involved. The method for manufacturing a web according to claim 3, wherein when the thickness of the entrapped air film is thicker than the film thickness, another segmentation model adjacent to a range of a segmentation model due to the wobble is obtained. When the film and the air layer are invaded, the length of the portion invading from the other divided model is proportional to the length of the film and the air layer of the certain split model, and is used as the equivalent film thickness and the like. Valuable air film thickness. A web winding method for forming a web roll having a web wound on a core, the web winding method comprising: a virtual roll making step using the same mesh as that used for the net roll a web, the web is wound onto the core to produce a virtual volume for evaluation; a calculation model is prepared to create a plurality of segmentation models, the segmentation model is to circumscribe the web in the width direction Split into multiple pieces; a calculation step for determining the circumferential stress and the radial stress in each of the segmentation models and for each winding radius based on the circumferential Young's modulus, the radial Young's modulus, and the winding tension distribution At least one type of stress; a defect occurrence stress range determining step, a winding radius generated according to a defect of the defect occurring in the virtual volume in the virtual volume forming step, and each of the described in the calculating step The stress of the winding radius is used to determine the stress occurrence range of the defect in which the defect may occur; the stress recalculation step, changing the winding tension pattern as the winding condition, the pressing pattern of the pneumatic press, and the thickness distribution in the width direction of the film Repeating the calculating step of at least one of a height of the knurled portion, an amplitude of the oscillating portion, and a period until the stress in the range of the specified winding radius is no longer included in the stress occurrence range of the defect; and the volume Winding a step in which the stress in the range of the prescribed winding radius found in the stress recalculation step is not included in the defect The winding conditions within the force range to the wound sites. The reel winding method according to claim 5, wherein in the calculating step, σ _r as the radial direction stress is a correction using Hatchel taken into account in the air film And derive the following formula to find out, r: winding radius Et: circumferential direction Young's modulus Er: radial Young's modulus, σ _t as the circumferential direction stress is the correction by taking the air film into consideration The following formula derived by Chir, is obtained. The web winding method according to claim 6, wherein when the thickness of the entrapped air film is obtained, the outermost air film thickness ho of the web is obtained by the following formula 1: R: radius η of the web roll: viscosity coefficient of air Vr: rotation speed of the web roll (line speed outside the web roll) Vw: transport speed T of the wound film: proportional to the film thickness of the split model The value of the tension of the entire film is distributed to the tension of each of the divided models. Using the ho obtained in the formula 1, the air film thickness ha is obtained by the following formula 2, and the air film thickness ha is throughout Pressing a part of the outermost mesh with a force of L in the width direction in the width direction to reduce the thickness of the air film after the outermost air thickness, L: force to press the film to the web W: width of the web roll If there is no film of another split model having a value of "thin film thickness + air film thickness ha", the film thickness + air film thickness ha The value is larger than the film thickness of the film having the largest film thickness in the film of the split model when the knurl is also a part of the film, and is obtained by the following formula 3A or formula 3B. The air film thickness h under the film of the maximum film thickness, and for the air film thickness under the film other than the film having the maximum film thickness, considering that the film is a rigid body and the film thickness distribution is The spacing between the surface of the film and the back side of the film below the film serves as the thickness of the entrapped air film, σ: Radius stress (calculation result when Hachil is wound up to the i-th layer) σ ₀ : Initial radial direction stress (calculation result when Hatchel is wound up to the i-1th layer) P _ap : Atmospheric pressure Ha: the thickness of the air film pressed by the pneumatic press with a force of L in the radial direction, and the thickness of the air film h that is entrapped when Hucker is rolled up to the i-1th layer, if present, if present The film of the other divided model having the value of the "thin film thickness + air film thickness ha", the value of the "thin film thickness + air film thickness ha" is larger than when the knurling is also a part of the film In the film of the split model, the film thickness of the film having the largest film thickness is large, and the size of the film film thickness + air film thickness ha of the portion other than the knurled portion is considered to be a rigid body. When the largest split film and the film under the split film are disposed at intervals of the air film thickness ha, the distance between the surface of each upper film and the back surface of the lower film is taken as the thickness of the entrapped air film, or Find the combination of the cross-sectional areas of the entrained air in each segmentation model The cross-sectional area of the gap between the area of the upper film and the back surface of the lower film is the same as the distance between the upper film surface and the lower film surface, and the distance between the surface of each of the upper films and the back surface of the lower film at this time is taken as The thickness of the air film is involved. The reel winding method according to claim 7, wherein when the thickness of the entrapped air film is thicker than the film thickness, another segment adjacent to a range of a segmentation model due to the wobble is obtained. When the film of the model and the air layer invade, the length of the portion invading from the other divided model is proportional to the length of the film and the air layer of the certain split model, and is used as the equivalent film thickness and Equivalent air film thickness. An internal stress calculation method is an internal stress calculation method of a mesh roll wound with a net on a core, the internal stress calculation method comprising: calculating a model making step, and preparing a plurality of segmentation models, wherein the segmentation model is a The web roll is divided into a plurality of tangentially in the width direction; and a calculation step for each of the split models and for each winding radius, based on the circumferential Young's modulus, the radial Young's modulus, and the winding The tension distribution is used to find at least one of the circumferential direction stress and the radial direction stress. The internal stress calculation method according to claim 9, wherein in the calculating step, the σ _r as the radial direction stress is a modified Hachier by taking into consideration the entrapment of the air film. The following formula is derived to find out, r: winding radius Et: circumferential direction Young's modulus Er: radial Young's modulus, σ _t as the circumferential direction stress is the correction by taking the air film into consideration The following formula derived by Chir, is obtained. The internal stress calculation method according to claim 10, wherein when the thickness of the entrapped air film is obtained, the outermost air film thickness ho of the reel is obtained by the following formula 1: R: radius η of the web roll: viscosity coefficient of air Vr: rotation speed of the web roll (line speed outside the web roll) Vw: transport speed T of the wound film: proportional to the film thickness of the split model The value of the tension of the entire film is distributed to the tension of each of the divided models. Using the ho obtained in the formula 1, the air film thickness ha is obtained by the following formula 2, and the air film thickness ha is throughout Pressing a part of the outermost mesh with a force of L in the width direction in the width direction to reduce the thickness of the air film after the outermost air thickness, L: force to press the film to the web W: width of the web roll If there is no film of another split model having a value of "thin film thickness + air film thickness ha", the film thickness + air film thickness ha The value is larger than the film thickness of the film having the largest film thickness in the film of the split model when the knurl is also a part of the film, and is obtained by the following formula 3A or formula 3B. The air film thickness h under the film of the maximum film thickness, and for the air film thickness under the film other than the film having the maximum film thickness, considering that the film is a rigid body and the film thickness distribution is The spacing between the surface of the film and the back side of the film below the film serves as the thickness of the entrapped air film, σ: Radius stress (calculation result when Hachil is wound up to the i-th layer) σ ₀ : Initial radial direction stress (calculation result when Hatchel is wound up to the i-1th layer) P _ap : Atmospheric pressure Ha: the thickness of the air film pressed by the pneumatic press with a force of L in the radial direction, and the thickness of the air film h that is entrapped when Hucker is rolled up to the i-1th layer, if present, if present The film of the other divided model having the value of the "thin film thickness + air film thickness ha", the value of the "thin film thickness + air film thickness ha" is larger than when the knurling is also a part of the film In the film of the split model, the film thickness of the film having the largest film thickness is large, and the size of the film film thickness + air film thickness ha of the portion other than the knurled portion is considered to be a rigid body. When the largest split film and the film under the split film are disposed at intervals of the air film thickness ha, the distance between the surface of each upper film and the back surface of the lower film is taken as the thickness of the entrapped air film, or Find the combination of the cross-sectional areas of the entrained air in each segmentation model The cross-sectional area of the gap between the area of the upper film and the back surface of the lower film is the same as the distance between the upper film surface and the lower film surface, and the distance between the surface of each of the upper films and the back surface of the lower film at this time is taken as The thickness of the air film is involved. The internal stress calculation method according to claim 11, wherein when the thickness of the entrapped air film is thicker than the film thickness of the film, another segmentation model adjacent to a range of a segmentation model due to the oscillation is obtained. When the film and the air layer are invaded, the length of the portion invading from the other divided model is proportional to the length of the film and the air layer of the certain split model, and is used as the equivalent film thickness and the like. Valuable air film thickness.