DE4116081A1 - METHOD FOR DETERMINING THE PARTICULAR RELATIVE WINDING DENSITY OF A FILM COIL REWINDED ON A ROLLER ROLLER AND A RULING METHOD FOR OBTAINING A CORRECTLY SELECTABLE, IN PARTICULAR RELATIVE WINDING DENSITY - Google Patents

Abstract

A process and device are disclosed for determining in particular the relative winding thickness of a foil strip (1) wound-up on a winding reel (3) and a regulation process allows a preselectable, in particular relative winding thinckness to be obtained. Until now, it was not possible to determine the relative, specific winding thickness, in particular during the process of winding a foil on a winding reel. According to the invention, this is possible by measuring the foil thickness during winding of the foil strip, by measuring the total length of the foil strip to be wound-up, by measuring the wound-up bale diameter at all points in time and by calculating the winding thickness from the formula rho = FD x FL / BRfl, in wich FD stands for the foil thickness, FL for the total length of the foil and BRf1 for the frontal, annular surface of the woundup bale (9) on the winding reel. The relative winding density can be used as the starting point for a regulation process of the winding traction forces that draw on the winding reel, as well as of the compressing forces in the case of a contact reel. The corresponding device has a simple design.

Description

The invention relates to a method for determining the esp special relative winding density on a winding roller wound film web during production as well as a rule procedure for obtaining a correspondingly selectable esp special relative winding density and an associated device.

In many technical areas, film webs have to be wound up will. Especially when it comes to film production for example stretched in a wide and / or transverse stretching system Foil wound on a winder roller. This can either after so-called gap winding or contact winding. In the case of gap winding, the film web becomes a winder roller on one roller deflected at a distance, whereas on contact always wrap the contact roller on the outermost wound one Layer of the wound film sheet presses.  

The relative specific winding density ultimately depends on the exerted on the film to be wound up by the winder roller Tensile forces, from the winding speed of the winder roller as well as, if applicable, of the one with the winder roller cooperating contact roller on the Fo to be wound lienbahn exerted contact forces. In addition, the relative Winding density also due to friction and friction, e.g. B. from La guides as well as from increases in friction due to weight gain of the wrapping bale, etc. Other influences are that Friction coefficients, surface roughness and the electro static behavior of the film.

For many applications it is important to consider the relative winding density determine or ensure that the values for different, the same bale wrapped on several winder rolls should be. However, there are no specific measurement methods. To previously known methods are, for example introduced from the winding roller onto the film to be wound up Tensile forces measured in order to achieve a specific winding density achieve. This can be done, for example, via the power consumption of the the winding roller driving motor take place. However, that is Error deviation relatively large, since only indirectly via the used power ascertainable tractive forces also the loss loss stungen to overcome the friction conditions and friction are required.

The object of the present invention is therefore the After to overcome parts according to the prior art and a verbes sertes measuring method for determining the winding density, in particular the relative winding density of one on a winder roller winding film web or an improved control process for Achieve a preselectable desired, especially relative To create winding density and an associated device.

The task is carried out according to the measuring method in claim 1, with respect to the control method according to the in  Claim 8 and with respect to the device according to the Claim 10 specified features solved. Advantageous Ausge Events are specified in the subclaims.

The present invention makes it possible for the first time to relative winding density with unprecedented accuracy determine, and this continuously, and if necessary depending a corresponding amount of rain tion for the winding roller or a possibly together therewith interacting contact roller or other in pairs kenden contact rollers to create a preselected ge desired winding density with as little deviation as possible windable film web can be realized.

In the measuring method according to the invention, on the one hand, the thickness and winding speed of the film web to be wound measured as the diameter of the wound bale. This allows the amount of film actually wound up compared the theoretically maximum achievable value chen. This maximum achievable theoretical value results by the measured outside diameter of the bale, where subtracting the volume of the winder roller, the maximum theoretical Depending on the table, the possible wrapping volume on the wrapping bale speed of the outer diameter can be determined. The special thing about that The method according to the invention is above all that the determined Measured values are determined in the so-called in-line method, and not so only the relative winding density not just depending on the finished wound bale, but above all the wrap density in the different diameter-dependent layers the entire thickness of the wrapping bale can be determined and evaluated.

Instead of a foil length measuring device, the Feed speed of the film web to be wound up like also measured the length of time for the winding process and above the length of the film web to be wound is determined.  

Instead of a thickness measurement, the basis weight of the film web to be wound up by appropriate measuring device be measured.

Finally, in a particularly preferred embodiment the film thickness or basis weight across the width of the merged foil web divided into several sections will be.

This can even cause film thickness fluctuations across the width of the film webs are measured, which changes the winding density section by width can be determined.

Finally, this can be done in-line Measuring method also as the basis for a corresponding control ver drive serve, namely those determined in the in-line method Data for the corresponding regulation and control of a winding process. About it can then namely before al lem in succession to a target curve for the desired specific Winding density during every step of the winding process at all times increasing and growing diameter of the wrapping bale one Make regulation so that depending on the awake always send the desired specific and bale diameter winding density dependent on the bale diameter is achieved.

The term "relative density" is the ratio of tat the actual weight of the wound film web in the ratio to the purely theoretically possible full weight of the bale without Inclusions of air with the same bale outer diameter understood. For the purposes of the present invention, therefore, the Be handle "winding density" in the sense of an actual winding density like but also the terms "winding weight", i.e. H. the weight of the did patent film smooth equivalent terms. Because even if he or she is found averaging the actual weight can add this to the pure theoretically maximum possible weight of a bale of the same size  be related in order to correspond again about that to obtain the relative winding density.

Further advantages, details and features of the invention result emerge from the following with reference to the attached Figures explained embodiments. Here show in a individual:

Figure 1 is a schematic perspective view of a winder roller with a contact roller and a film web to be wound.

Fig. 2 is a schematic end view of a modified embodiment for a so-called "wrap gap";

Fig. 3 shows a circuit arrangement for determining a Diagram mes with respect to the measured relative winding density as for controlling a winding device.

In Fig. 1, a film web 1 to be wound is drawn with a film web width FB, which is wound with a feed speed or feed speed V onto a winder roller 3 .

In the illustrated embodiment, the winding of the Fo carried lien web 1 after the so-called. Contact wrapping, wherein the film web is deflected at a contact roller 5 1, which pushes always clock force with the Kon P _K on each outermost layer of the 3 winding bale 7 being roll on the winding .

The winding roller 3 is driven in a suitable manner and rotates with a preselectable, possibly increasing with increasing the diameter of the winding bale 7 rotating speed, so that a certain winding tension force K _W always acts on the film web 1 to be wound up.

In the exemplary embodiment shown, a film thickness or sheet basis weight measuring device 9 , a film web length measuring device 11 and a wrap thickness measuring device 13 , hereinafter also referred to as a diameter measuring device 13 , are provided.

During operation, the measuring and evaluation electronics 15 shown schematically in FIG. 3 and the winding process itself are started when the winder roller 3 is still unwound. So there are the film thickness measuring device 9, the film thickness F _D , for example, the measured rotation of the contact roller 5 or a separate length measuring device 11 from the beginning of the wound film web length F _L and the increasingly growing outside diameter D _{W of} the wrap bale 7 the wrap thickness gauge 13 measured. In addition, the outer circumference or the diameter d _{w of} the unwrapped winding roller 3 can also be measured as an initial value or, if known, otherwise entered as a constant in the measuring and evaluation electronics 15 .

The evaluation follows the formula

where B _{Rfl represents} the end face of the wrapping _bale .

This can in turn be obtained by measuring the radius or diameter by means of the wrapping thickness measuring device 13 according to the formula:

B _Rf = (D _W ² - d _w ²) × π / 4

Instead of the film length, however, the film web feed or line speed v and the time elapsed since the start of the winding process can also be measured using a separate timer, which also results in the length of the film web that is always wound up on the winding roller 3 according to the equation

F _L = v × t

respectively.

results, where t is the value for the elapsed time since the start of the running winding roll is.

Finally, with the measuring device 9 , it may not be possible to determine the film thickness, but rather the _{film basis weight} G _Ffl . In this case, in order to achieve the relative winding density in particular, it is necessary that the film surface weight measured in this way is divided by the specific weight of the film web material, so that the relative winding density is obtained according to the following formula:

The above-mentioned measured quantities are measured continuously or at discreet, as short time intervals as possible, so that not only the specific weight of the total bale at the end of the wrapping process, but also the relative wrapping density depending on the various diameters of the diameters during the wrapping process itself Obtain wrapping bales 7 .

These measured variables can then be used to determine the relative winding density as a function of the diameter of the winding bale 7 , as can be shown, for example, on the display device 17 according to FIG. 3.

From the statements made above it also appears that the Foil width is not included in the equation or both at the determination of the basis weight of the film web and the the theoretical weight of the wrapping bale is taken into account should be and therefore no change in the measurement result leads.

Finally, the film thickness or film basis weight can be measured not only in the sense of a measured variable for the entire film width, but for various film sections which are divided in the transverse direction of the film web. This can then be used to form an average or the measurement results for the film thickness or film basis weight are multiplied by the respective film section width ΔF _B and the above formulas are then divided over the entire film width F _B or are displayed section by section. In the exemplary embodiment shown in FIG. 1, 6 separately measured sections A to F are provided.

The measured and determined values for the relative winding density can not only be read out and displayed, but can also be used at the same time as control and manipulated variables for driving the winding roller 3 and a contact roller 5 , which may co-operate therewith, namely once the winding tension -Control forces K _W on the winding roller as well as the contact pressure P _K on the contact roller accordingly, so that the measured relative specific winding density ρ corresponds to a pre-selectable target curve.

In the drawings, the specific drive elements for the winding device such as the actuators for generating the contact pressure forces through the contact roller for the sake of simplicity is not Darge. Instead of the winding bale thickness gauge 13 shown only schematically in Fig. 1 in the form of a on a Schlit th along a guide with increasing bale diameter under the touch of a finger or a roller movable measuring device but optical or other sensory measuring devices can also be used to the increasing radius, the diameter or other representative values for the increasing bale diameter. Another very elegant method for determining the winding diameter that is constantly increasing during the winding process is to measure the film web feed speed v on the one hand and the rotation speed Ω on the other hand. Because with increasing winding diameter even with, for example, unchanged, ie constant film web feed speed v, the rotational speed of the winding roller 3 decreases, so that the current size of the winding bale diameter can be concluded from the changing ratio. This evaluation method is shown in dashed lines in Fig. 1 for evaluation electronics 13 '.

In Fig. 2, an example of a slit winding is shown in a schematic front view, in which the deflection roller shown there 5 'is not in direct contact with the winding roller 3 .

But even in such an embodiment, based on the measuring method explained above, a corresponding control method can be carried out to generate the desired winding tensile forces K _W to be applied by the winding roller 3 .

The measurement and control method according to the invention and the associated device have been described in the event that the individual method steps were carried out either continuously or in discrete temporal steps. The film thickness, which can change, was measured continuously or in discrete temporal steps. The formula given in claim 1 for calculating the relative winding density as a function of the product of F _D × F _L is preferably implemented in practice in such a way that in the case of measurements taking place in discrete temporal steps, the above-mentioned product is composed of the product reproduced below Sum of individual products

Σ (F _D ) _i × (ΔF _L ) _i

This means that the specific film thickness is always measured at discrete time intervals and multiplied by the film partial length section ΔF _L, which is moved further in the time unit. Totaling is carried out over the entire length of the wound film web.

Instead of the sum shown above, in particular with continuous measurement for an integrative evaluation according to the following formula

be passed over.

Of course, it is also possible to average the value F _{D with} respect to all measured values, in order then to obtain the corresponding area value by multiplying the total length F _L.

In certain cases, the determination of the relative winding should density only for the total wrapped bale from In interest and should also be the film thickness by one Vary the mean as little as possible, it would be under certain circumstances also sufficient, only once measured or pre-entered value for the film thickness, and only the Ge total length of the film web to be wound and only the final bale diameter after the wrapping process (or a related diameter size) once measure to determine the relative winding density. With in other words, in this case, it could be continuous or measurement of the Foil thickness (or related sizes) of Fo lienbahn as well as a continuous or in discrete temporal Measurement of the wound bale diameter sers etc. can be dispensed with. It is expressly emphasized that this embodiment also belongs to the invention.

Claims (12)

1. Method for determining (measuring) the, in particular, relative winding density of a film web to be wound on a winding roller, with the following method steps:

• - preferably continuous measurement of the film thickness of the film web to be wound, continuously or in discrete temporal steps,
• Measurement, in particular continuous measurement of the total length of the film web to be wound up, or in discrete temporal steps,
• - preferably continuous, continuous or in discrete temporal steps, measurement of the wound up, at least the finally wound up bale diameter, radius or diameter or radius increase,
• - and calculation of the winding density according to the formula where F _{D is} the film thickness, F _{L is} the total film length and B _{Rfl is} the end-face ring surface of the wrapped bale wound on the winder roll.

2. The method according to claim 1, characterized in that the end face of the ring surface depending on the measured diameter, the radius or the increase in diameter is essentially Chen according to the formula B _Rf = (D _W ² - d _w ²) × π / 4 is determined , where D _{W is} the diameter of the wound ball diameter and d _{w is} the predetermined or measurable diameter of the unwound winding roller or the bale diameter from the last calculation cycle. 3. The method according to claim 1 or 2, characterized in that instead of the film thickness F _D, the film _{basis weight} G _{Ffl is measured} continuously continuously or in discrete temporal steps, the film basis weight G _{Ffl being divided} by the specific weight ρ _{FM of} the material of the film web. 4. The method according to any one of claims 1 to 3, characterized in that the entire length of film web by measuring the film web feed or system speed and measuring the total time t according to the formula F _L = v × toder is determined. 5. The method according to any one of claims 1 to 4, characterized in that the film thickness F _D or the film _{basis weight} G _{Ffl of} the film web to be wound is measured in several film sections offset in the transverse direction to the film web. 6. The method according to claim 5, characterized in that the values measured for a plurality of film _sections for the film thickness F _D or the film _weight G _{Ffl are averaged} according to the number of film _sections . 7. The method according to claim 5, characterized in that the values measured for a plurality of film sections for the film thickness F _D or for the film weight F _{fl are} each multiplied by the associated width ΔF _{B of} the film section in question and divided by the total width of the film F _B or that the wrap is displayed in dense sections. 8. Control procedure to achieve a correspondingly selectable in particular relative winding density, characterized in that the controlled variables for the winding tensile forces such as one if necessary provided contact pressure by means of a contact roller in depend ability of the measuring method according to one of claims 1 to 7 er be averaged. 9. Control method according to claim 8, characterized in that the controlled variables depending on the difference of the determined ten measured variables can be determined for preselectable setpoint variables. 10. Device for performing the method according to one of claims 1 to 9, characterized by a film thickness or film basis weight measuring device ( 9 ), a film web length measuring device ( 11 ), optionally in the form of a feed or system speed measuring device and a time measuring device as well as a winding bale diameter measuring device ( 13 ) measuring the diameter, the radius or the external dimension or a correlating size, or calculation of the winding bale diameter as well as evaluation electronics ( 15 ) for determining the particular relative winding density of a film web to be wound up. 11. The device according to claim 10, characterized in that the film thickness or film basis weight measuring device ( 9 ) performed a multiple measurement in different sections lying transversely to the film feed path. 12. The apparatus of claim 10 or 11, characterized in that by means of the evaluation electronics ( 15 ), the winding density by controlling the winding tensile forces of the winder roller ( 3 ) and, if appropriate, the contact pressure of a contact roller ( 5 ) can be regulated.