JPH0622849B2 - Profile control method for film etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a profile control method for performing profile control of a film, a sheet or the like (hereinafter, simply referred to as a film) by a screen operation by a pair of movable lips.

<Prior Art> Taking the case of upper and lower movable lips as shown in FIG. 7 and FIG. 8 as an example, a pair of movable lips 1 and 2 will be described.
There is known a molding die such as a plastic film for adjusting the die lip gap 5 by pushing and pulling die bolts 3a, 3b, 3c ... And 4a, 4b.

This is more effective than a conventional fixed die, compared to a molding die that adjusts the die slit gap from only one side of the movable lip by pushing and pulling a plurality of die bolts that have movable lips in the width direction. There is an advantage that the slit gap, that is, the thickness of the film or the like can be adjusted.

For example, if the wavelength is λ and the pitch of the die bolt is p, then λ =
The displacement curve of 2p is approximated by a cosine curve, and the upper lip is shown in Fig. 2.
It becomes like (a), Displacement of. Similarly, the lower lip has a displacement curve as shown in Fig. 2 (b), And the combined displacement is the displacement curve as shown in Fig. 2 (c), that is, Becomes

Therefore, on the contrary, if there is a displacement line in Fig. 2 (c), it can be assigned to each in Fig. 2 (a) and (b) by the upper and lower lips respectively, and the adjustment of both sides is 2 in comparison with the adjustment of one side. Double displacement can be obtained.

<Problems to be Solved by the Invention> However, the change in the die slit gap is a combination of the changes in the upper and lower die lip displacements as described above,
Compared to the one-sided die slit gap adjusting method, the number of adjusting elements is increased, more complicated operations are required, and there is a drawback that good results cannot be obtained by simply operating the upper and lower divoles.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a profile control method capable of easily and effectively adjusting the thickness of a film or the like by die lips on the upper and lower surfaces.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a plurality of die bolts in which die slit gaps formed by a pair of movable lips are provided at equal intervals in the width direction of each lip. In a profile control method for a film or the like in an automatic molding die that pushes and pulls a die, the die bolts are arranged in asymmetrical positions with respect to one die bolt, and the measurement deviation amount of the profile is substantially divided into two. Then
The profile control method for a film or the like is characterized in that the amount of operation for each die bolt of each movable lip is calculated by assigning the die bolts of the pair of movable lips.

Further, the thickness adjustment of the film or the like from the both surfaces of the pair of movable lips is performed only in a part (both ends) in the die width direction.

<Operation> The profile measurement deviation amount is divided into two parts, which are assigned as the upper and lower die bolts respectively, and the operation amount can be calculated for each of the upper and lower die bolts. As a result, the die bolts are arranged at a shorter pitch than in the symmetrical position, so that the film thickness can be corrected at a finer pitch.

<Embodiment> Next, one embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 10 is a film forming die attached to an extruder 11.
A die slit gap 14 is formed by a pair of movable lips 12 and 13, and a plurality of die bolts are provided in each width direction.
Adjustment can be done by pushing and pulling 15 (15a, 15b ...) and 16 (16a, 16b ...). 17 is a film discharged from the die slit gap 14 and is a cooling roll 18
After that, it is wound up by a winding device (not shown) via a processing device 19 for stretching. 20 is the film
It is a thickness gauge that detects the profile across the full width of 17
The detected value is input to the computer 22 via the interface 21. The computer 22
Is provided with a cpu 23 for performing various types of arithmetic processing and a RAM 24 for storing constants for performing various types of arithmetic processing or numerical values input from the outside such as detection values detected by the thickness gauge 20. Therefore, the film 17 detected by the thickness gauge 20
Profile is compared with a target profile stored in advance in the RAM 24 as will be described later, its deviation amount is calculated, and the profile is divided into two and the die bolts 15a, 15b, ... , 16b ... The operation amount is calculated for each. Reference numeral 25 denotes a power control unit which causes the operation amount of each of the die bolts 15 and 16 calculated by the computer 22 to act on a die bolt driving device (not shown) via an interface 26.

Next, the action and operation will be described. In the description, only the movable lip 12 will be described, and since the movable lip 13 operates and operates in the same manner as the movable lip 12, the description thereof will be omitted.

Now, the displacement amount δ _i of the lip clearance δ _{i at} the i-th position of the die bolts (15a, 15b ...) With respect to the j-th bolt load p _j satisfies the following equation (1) according to Hooke's law δ _i = f _{i・ J}・ p _j (1) (However, j = 1,2,3 …… n, f _{i ・ j} is a proportional constant for the jth bolt load of the lip clearance at the ith position.) This is because when a specific bolt is operated from among multiple die bolts, not only the lip gap at the position where the bolt acts changes but also other parts are affected, which is called the mutual interference effect. There is.

i-th and the target film thickness pattern t _i, the expressed deviation e _i of the measured thickness gauge 20 i-th film thickness pattern m _i is in general in the following (2) e _i = m _i - t _i (2) Variation Δp _j (j of each bolt load for obtaining the deviation value e _i
= 1,2 ... n), the following equation (3) is generally established.

That is, e ₁ = f _1.1 Δp ₁ + f _1.2 · Δp ₂ + f _1.3 Δp ₃ + …… ＋ f _{1 · n} Δp _n e ₂ = f _2.1 Δp ₁ + f _2.2 · Δp ₂ + f _2.3 Δp ₃ + …… + f _{2 · n} Δp _{n ・ ・ ・} e _n = f _{n ・ 1} Δp ₁ ＋ f _{n ・ 2} Δp ₂ ＋ f _{n ・ 3} Δp ₃ ＋ …… ＋ f _{n ・ n} Δp _n , and the proportional constant f _{i ・ j} is analytically or experimentally It can be calculated, and if it is stored in the RAM24 in advance, cp
From the deviation value e _i and the proportionality constant f _{i · j,} u23 can solve the above-described simultaneous polynomial equation for Δp _j .

On the other hand, since each Δp _j is also the amount of change in the bolt reaction force, the operation amount ΔB _{· i} of each bolt can be obtained from the following equation (4).

That is, the bolt operation amount δ _Bi determined by the present invention is expressed by the sum of the target displacement amount e _i of the first term and the elastic deformation amount p _i / K of the bolt itself due to the load change of the second term which determines the correction amount. Is
Similarly, the amount of bolt operation of the movable lip 13 can also be obtained, and the portions allocated to the movable lips 12 and 13 can be shared.

Here, the arrangement of the die bolts of the upper and lower movable lips will be described. When the arrangement of the die bolts is symmetrical with respect to the upper and lower sides, the change amounts as shown in FIGS. , Amount Δx of peak position of error component of wavelength λ = 2p
Then, if Δx = p / 2, it cannot be corrected at all. Therefore, when the phase is staggered, for example, when the phase is shifted by Δx = ± p / 2, the upper lip is as shown in FIG.
The displacement curves are as shown in (b). Therefore, the combined displacement curve y ₁ + y ₂ is as shown in Fig. 3 (C). It is possible to select either the solid line or the dotted line, and there is no part that cannot be corrected as in the case of top / bottom symmetry, and it is more effective to dispose the die bolts asymmetrically in the top / bottom.

In addition to the arrangement of the die bolts, U-shaped grooves or similar grooves 33, 34 are provided in a part of the intervals of the plurality of die bolts such as the upper and lower movable lips 31 and 32 as shown in FIG. As a result, a thin portion is provided between the bolts to improve the flexible flexibility of the movable lip, and the theoretical limit wavelength λ = 2p can be corrected.

Further, in the above description, the die bolt was described as a one-sided mold that pushes the movable lip, but the movable bolt 41 may be pushed and pulled by the die bolt 40 as shown in FIG. 5, and the die bolt 50 as shown in FIG. The movable lip 51 may be pushed by and the movable portion 51 may be pushed and pulled alternately by the die bolt 52 like pulling.

Further, the adjustment of the lip gap by the die bolts provided on the pair of movable lips as described above is effective not only for the entire width of the die but also for a part in the width direction.

<Effect> Since the die bolts for adjusting the die slit gap of the pair of movable lips are arranged at asymmetrical positions with respect to one die bolt, the other die bolts are arranged at asymmetrical positions, which is about 1.4 times as much as the conventional one-sided adjustment. The amount of displacement can be adjusted and the pitch in the adjustment can be finely adjusted.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. Fig. 2 is a diagram explaining that the displacement curve is shared by the upper and lower lips when the die bolt is in the upper / lower symmetrical arrangement, (a) shows the displacement curve of the upper lip, and (b) shows the lower part. Displacement curve diagram of lip sharing, (c) Displacement curve diagram before dividing into upper and lower parts, and Fig. 3 shows displacement curve when die bolt is not symmetrically arranged in upper and lower parts. In this figure, (a) shows the displacement curve of the upper lip sharing, (b) shows the displacement curve of the lower lip sharing, and (c) shows the displacement before dividing into upper and lower. Curved diagram. FIG. 4 is a view showing another embodiment of the present invention, in which a U-shaped groove or a groove similar thereto is provided in each gap of the die bolt. FIG. 5 is a view showing still another embodiment of the present invention, showing a case where the movable lip is pushed and pulled by a die bolt. FIG. 6 is a view showing still another embodiment of the present invention, showing a case where the movable lips are alternately pushed and pulled by die bolts.
FIG. 7 is a view of a conventional device. FIG. 8 is a view showing a II cross section of FIG. 7. 12,13,41,51 …… Movable lip, 15,16,40,50 …… Die bolt, 20 …… Thickness gauge, 22 …… Computer, 31 …… Upper movable lip, 32 …… Lower movable lip, 33 , 34 …… U-shaped groove.

Claims (2)

[Claims] 1. A profile of a film or the like in an automatic die for molding in which a die slit gap formed by a pair of movable lips is adjusted by pushing and pulling a plurality of die bolts provided at equal intervals in the width direction of each lip. In the control method, the die bolts are arranged at positions asymmetric to each other with respect to one of the die bolts, and the measurement deviation amount of the profile is substantially divided into two so as to share the die bolts of the pair of movable lips. A profile control method for a film or the like, characterized in that the operation amount for each die bolt of each movable lip is calculated. 2. A die slit formed by the pair of movable lips is provided at both ends in the width direction of the die, and the die bolts are arranged at asymmetrical positions with respect to one die bolt. The profile control method for a film or the like according to claim 1).