JPH03286827A - Measurement device of film thickness - Google Patents

Abstract

PURPOSE:To enable the changing amount in longitudinal direction to be removed from the measured value of the film thickness in the width direction of a film by a method in which the film thickness in the width direction of the film is measured, and film thickness-signal, scanning position-signal and the pressure signal by measuring resin-extruding pressure are outputted, and the changing amount in the longitudinal direction of the film is obtained, whereby the measured value of film thickness is corrected. CONSTITUTION:The film thickness-measurer 10 which measures the film thickness of a film 9 is arranged on the film 9 in running of the film 9, and the film-thickness is measured. The resin-extruding pressure signal from a resin-extruding pressure guage 5 and the film thickness signal from the film thickness measurer 10 are sent to the memory 13 of a microcomputer 12 with the scanning position signal which shows the position of the film thickness measurer 10 from a scanning device 11. On the basis of the resin-extruding pressure signal, the film-thickness signal and the scanning position signal stored in the memory 13, the operational part 14 of the microcomputer 2 achieves the correcting operation for the film thickness to be measured by the film thickness measurer 10. The changing amount of the film thickness in the scanning direction of the film 9 is obtained from the resin-extruding pressure of an adapter 2, and the measured value of the film thickness in the width direction of the film 9 is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device for measuring the film thickness in the width direction of a running film in a film processing machine.

[Prior Art] Conventionally, in a film processing machine such as a laminator, when measuring the film thickness in the width direction of a film to be manufactured, the film thickness meter is scanned in the width direction of the traveling film 100. As shown in FIG. 4, the thickness gauge does not scan in a direction perpendicular to the longitudinal direction of the film 100, so it scans along a path m inclined in the width direction.

On the other hand, in the extruder of the film processing machine, the extrusion pressure of the resin fluctuates by several percent over time, as shown by curve n in FIG. For this reason, the thickness of the film 100 formed is the fourth
It changes over time as shown in the figure.

[Alji to be solved by the invention] In general, in film processing machines, even if the gap interval between the extrusion ports of the extruder is constant, the amount of resin extruded inevitably changes every few seconds. Even if the film thickness in the longitudinal direction changes to some extent, if the film thickness distribution in the width direction of the film is flat, there is no need to change the gap interval of the extrusion port.

However, with conventional film thickness measurement devices, the film thickness meter scans a path that is inclined to the width direction of the film, so it includes changes in the film thickness in the longitudinal direction, so it is difficult to accurately measure the film thickness in the width direction of the film. There is a problem in that the measured value of film thickness cannot be used as accurate information for controlling the gap interval of the extrusion port in an extrusion mode in a film processing machine.

SUMMARY OF THE INVENTION Accordingly, a technical object of the present invention is to provide a film thickness measuring device that can remove changes in the longitudinal direction of the film from the measured film thickness in the width direction of the film in a film processing machine.

[Means for solving the problem] According to the present invention, there is provided a membrane used in a film processing machine that extrudes resin from an extrusion port of an extrusion molding machine to form a film, and for measuring the film thickness of the film during running. A film thickness measuring device that outputs a film thickness signal that is scanned in the width direction of the running film and measures the film thickness of the running film, and a scanning position signal that indicates a measurement position of the film thickness. a measuring means, a resin extrusion pressure measuring means for outputting a resin extrusion pressure signal obtained by multiplying the resin pressure at the extrusion port by f#J, and a storage means for storing the film thickness signal, the scanning signal, and the resin extrusion pressure signal; A film thickness correction value for correcting the film thickness measured by the film thickness measuring means is determined based on the film thickness signal and extrusion pressure signal stored in the storage means, and the film thickness correction value is calculated based on the film thickness correction value. A film thickness measuring device is obtained, which is characterized by comprising a calculation means for performing calculations for correcting the thickness.

[Function] In the film thickness measuring device of the present invention, the film thickness is measured by scanning the film thickness measuring means in the width direction of the film.
and outputs a film thickness signal and a scanning position signal.
The resin extrusion pressure measurement means outputs a resin extrusion pressure signal, the storage means stores the film thickness signal, scanning position signal, and resin extrusion pressure signal, and the calculation means calculates changes in the longitudinal direction of the film based on these signals. The measured value of the film thickness by the film thickness measuring means is corrected using this change.

Therefore, it is possible to determine the corrected and highly accurate film thickness distribution in the width direction.

[Example] Embodiments of the present invention will be described in detail based on the drawings.

In FIG. 1, reference numeral 1 indicates an extruder.

This extruder 1 extrudes a molten resin as a film 4 from a T-die 3 via an adapter 2.

A resin extrusion pressure gauge 5 for measuring the extrusion pressure of the resin is disposed at the adapter 2, which is the extrusion port of the extruder 1. The film 4 extruded from the T-die is laminated with a thin film base material 8 such as paper or other sheet by a cooling roll 6 and a pressing roll 7 to form a film 9 as a product.

This film 9 is moved by an arrow a by a winding device (not shown).
It is moved in the direction of and wound up.

A film thickness meter 10 for measuring the film thickness of the film 9 while the film 9 is running is placed above the film. This film thickness: 'F1o is measured by the scanning device 11 in the longitudinal direction of the film, that is, in the direction perpendicular to the running direction (
It is designed to be scanned back and forth in the direction of missing marks).

- When the film 9 is running in the direction of arrow a,
As shown in FIG. 2, the film thickness meter 10 measures the film thickness of the film 9 by scanning along a path shown by a two-dot chain line C.

The resin extrusion pressure signal from the resin extrusion pressure gauge 5 is given to the storage section 13 of the microcomputer 12, and
The film thickness signal from the film thickness meter 10 is also sent to the microcomputer 12.
is given to the storage unit 14 of.

Furthermore, the scanning position signal indicating the position of the film thickness meter 10 from the scanning device 11 is also transmitted to the storage section 1 of the microcomputer 12.
3 at the same time as the film thickness signal.

Based on the resin extrusion pressure signal, film thickness signal, and scanning position signal stored in the storage unit 13, the calculation unit 14 of the microcomputer 12 performs calculations to correct the film thickness measured by the film thickness meter 10. .

The calculation result of the calculation unit 14 is given to the display device 15 and displayed.

Next, the calculations in the calculation section 14 of the microcomputer 12 will be explained in detail.

When molten resin at a constant temperature passes through a constriction opening of a constant shape such as in T-die 3, the pressure loss P and flow mQ there
The relationship with is expressed by the following formula.

Q-apl...(1) Here, α
: proportionality constant, n: constant specific to resin.

From the above equation (1), a relationship expressed by the following equation is derived between the flow rate change amount ΔQ and the associated pressure change amount ΔP.

Q nP In the present invention, by utilizing this relationship, the amount of change in the film thickness in the running direction of the film 9 is determined from the amount of change in the resin extrusion pressure of the adapter 2, and the measured value of the film thickness in the width direction of the film 9 is obtained. Correct.

Now, let tl be the time during which the film 4°9 is transferred from the T-die 3 to the film thickness meter 10. And resin extrusion pressure gauge 5
The resin extrusion pressure signal P (t) measured in Figure 3 (A)
Suppose that the change occurs as shown by the curve.

First, the calculation section 14 calculates the resin extrusion pressure f shown in FIG.
: Figure 3 (
The resin extrusion pressure signal P' (t) shown by the curve B) is determined.

The resin extrusion pressure signal 1'' (t
) is calculated, and the following equation is calculated for each time based on this average value Pm.

On the other hand, the average value dm in one scan of the film thickness signal d(t) shown by the curve in FIG. 3(B) is determined.

Since the film 9 as a product is running at a constant speed, Δ d (t) = d (t) dm
-(,4), then .

Therefore, from equations (2), (3), and (5), the following equation can be obtained.

(6) Therefore, using the above d (t) and Ad (t), the corrected film thickness signal Δa (t) can be expressed by the following equation.

a (t) −d (t) −Ad (t) −(
7) In the illustrated embodiment, a film processing machine that processes a film having a thin film base material was used as an example. However, the present invention can also be applied to a film processing machine that processes a film that does not have a thin film base material. Can be applied.

[Effects of the Invention] As explained above, according to the film thickness measuring device of the present invention,
In a film processing machine, it is possible to remove the change in film thickness in the longitudinal direction of the film from the measured film thickness in the film width direction.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an outline of an embodiment of the present invention, and FIG. 2 is a diagram showing an outline of an embodiment of the invention.
FIG. 3 is a plan view for explaining the total film thickness 11JI measured by the film thickness meter in the embodiment shown in FIG. 1; FIG. The figure shows the total #I path of the film in a film thickness meter used in a conventional film processing machine, and FIG. 5 shows the change in resin extrusion pressure in the film processing machine. In the figure, 1...extruder, 3...T die, 4, 9...
Film, 5... Resin extrusion pressure gauge, 10... Film thickness gauge, 12... Microcomputer, 13... Storage unit,
14... Arithmetic unit. Figure 4 Figure 5

Claims (1)

[Claims] 1. A film thickness measuring device used in a film processing machine that extrudes resin from an extrusion port of an extrusion molding machine to form a film, and for measuring the film thickness of a running film. a film thickness measuring means for outputting a film thickness signal that is scanned in the width direction to measure the film thickness of the running film and a scanning position signal that indicates a measurement position of the film thickness; and a resin pressure at the extrusion port was measured. a resin extrusion pressure measuring means for outputting a resin extrusion pressure signal; a storage means for storing the film thickness signal, the scanning signal, and the resin extrusion pressure signal; and a method based on the film thickness signal and the extrusion pressure signal stored in the storage means. The film thickness measuring means calculates a film thickness correction value for correcting the film thickness measured by the film thickness measuring means, and calculates the film thickness based on the film thickness correction value. Film thickness measuring device.