JP2637492B2 - Deformation error correction structure for T-die lip driver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a deformation error correction structure for a T-die lip driving section.

(Prior Art) In a laminating process of coating a resin such as paper, aluminum foil, or plastic with a resin, the need for a coating uneven thickness control system is increasing in terms of processing quality, resin saving, and the like. In order to realize the present system, T
The die is the technical point.

Conventionally, the amount of the molten resin flowing out of the T-die has been adjusted by manually rotating a gap adjusting bolt provided on the lip portion. However, some have automated this and adopted drive methods such as the "heat bolt method" and the "servo motor method". The heat bolt method is a method that utilizes the thermal expansion of a bolt, but has a problem in that it requires time for heating and cooling and has low response. Further, the servo motor system is a system in which one or a plurality of servo motors are used to sequentially rotate bolts, and is based on the idea of converting a conventional manual operation into a robot. However, there is a problem that all bolts cannot be driven at the same time, resulting in a longer adjustment time.

(Problems to be Solved by the Invention) In view of the problems of the prior art, it is an object of the present invention to provide a structure of a T-die lip drive unit capable of adjusting a gap at high speed and with high accuracy. In particular, it is an object of the present invention to provide a structure for correcting a deformation error of a T-die lip drive unit in consideration of the influence of molten resin pressure.

(Means for Solving the Problems According to the Invention) The main body structure 1, a plurality of bellows 2 disposed on the side of the main body structure 1, are fastened to the respective bellows 2 at the upper portion, and fastened to the lip portion structure 12 at the lower portion. Weared bellows 2 and lip
The drive unit structure 3 is connected to the plurality of bellows 2 in the width direction of the lip 13, and the drive unit structure 3 is divided into a plurality of parts. A displacement sensor 15 for detecting displacement of the lip portion 13 due to the resin flow pressure is provided at an upper portion, and a detection value of the displacement sensor 15 is fed back to compare a detection value of the displacement sensor 15 with a displacement amount target value. The obtained positive / negative value is converted into a gas pressure Pa by an electropneumatic converter, and the gas pressure Pa is supplied to the bellows 2 to control the lip opening.

(Operation) When compressed air is sent to the upper and lower bellows, the bellows expands, and a moment acts on the lip portion from the driving portion structure via the lip portion structure to be displaced. The displacement amount is detected by a displacement sensor, and the displacement amount is fed back and controlled. Therefore, even if the lip portion is deformed due to resin pressure, etc., this is immediately corrected, and a high-precision lip opening degree is obtained. Can control.

(Example) FIG. 1 is a perspective view of a T-die lip portion embodying the present invention. The T-die is roughly composed of three parts. That is, it is composed of a main body structure 1, a plurality of bellows 2 arranged on one side in the longitudinal direction of the main body structure 1, and a drive section structure 3 connecting the bellows 2 and the lip portion 13. An arbitrary number of drive units can be configured by these combinations.

2 is a side view of FIG. 1, FIG. 3 is a bottom view of FIG. 2,
FIG. 4 is a sectional view taken along line IV-IV of FIG. Each bellows 2 is fixed to the main body structure 1 by bolts 8.
Also, each bellows 2 is addressed to each drive unit structure 3 by two (2a and 2a).
2b) It is fixed with bolts 7. A seal 4 or 5 (FIG. 4) is provided at a fixing portion of each bolt to prevent leakage of compressed air from inside the bellows 2.

An elastically deformable portion 11 is provided in the vicinity of the nozzle portion of the main body structure 1, and a lip portion structure 12 below and integrated with the elastically deformable portion 11 is formed as an integrated structure. The lip portion structure 12 and the drive portion structure 3 are integrally fastened by bolts 6.

Each of the divided drive unit structures 3 (3a, 3b ...) is provided with two bellows 2a and 2b (FIG. 4) which are respectively disposed on the upper and lower sides. Air is supplied from an air supply port 10 formed in the bellows 1 to an bellows 2a (upper part in the figure) via an air passage 9a provided in the bottom of the bellows 2a via an air passage 9a also provided in the main body structure 1. The lower bellows 2b is also supplied from a common air passage 9a through an air passage 9c provided at the bottom of the bellows.

The driving unit structure 3 is divided into a plurality of structures 3a, 3b, 3c... 3n (eight in FIG. 1 and five in FIG. 2), and each lip structure 12 Has a dividing groove 14 between the adjacent lip portion structures. Thus, each drive unit is composed of a plurality of independent drive mechanisms and a structure having a low degree of interference between adjacent structures.

Reference numeral 15 denotes a displacement sensor fixed on the upper part of the drive unit structure 3, which detects a gap g between the drive unit structure 3 and the main body structure 1. Then, the detected value is fed back to a control device (not shown) via the wiring 16.

When compressed air is supplied from the air supply port 10 to each of the bellows 2 (2a, 2b), the mechanical rigidity of the bellows 2 (2a, 2b) in the axial direction between the main body structure 1 and the drive unit structure 3 is reduced. Since it is lower than other structures, a force is generated in the direction indicated by the arrow _{1 in} FIG.力 The force in _one direction is transmitted to the elastic deformation portion 11 as a moment. Then, the elastic deformation portion 11 is
And because the mechanical rigidity lower than that of the driving unit structure 3, the elastic deformation is generated in this portion, moves to the lip portion 13 is chi ₂ direction (Figure 4). This displacement is bellows 2 (2a, 2b)
It is approximately proportional to the transmitted moment or the pressure of the compressed gas from which it is transmitted.

As described above, the lip opening can be arbitrarily controlled by controlling the pressure of the compressed gas supplied to the bellows 2 (2a, 2b). Further, each drive unit structure (3a, 3b
By simultaneously and independently controlling the gas pressure supplied to 3n), it is possible to simultaneously and independently control the lip openings of many points.

However, actually, the molten resin flows inside the lip, and the lip opening (displacement amount) is determined only by the resin pressure generated near the lip and the gas pressure in the bellows. In other words, there is a displacement error due to the resin pressure. The bellows gas pressure control method is effective only when the resin pressure or its fluctuation is small and the influence on the lip displacement is small, but when the resin pressure or its fluctuation becomes large, the displacement error due to this pressure is increased. Cannot be ignored.

FIG. 7 shows the shape of the lip when the resin pressure is high under the gas pressure control method, and the broken line in the figure is the shape. The mechanical rigidity value is particularly low in the elastically deformed portion. Since such a lip deformation becomes an obstacle in controlling the resin flow rate, in the present invention, a displacement amount between the main body structure 1 and the driving portion structure 3 is measured by the displacement sensor 15 and the driving is performed by feeding back the measured amount. The method is adopted.

FIG. 8 shows a block diagram of this control system, and includes a displacement sensor.
The detected value obtained by step 15 is compared with the target displacement amount, and the compared positive / negative value is converted into a gas pressure Pa by the electropneumatic converter in the control circuit. This gas pressure Pa is supplied to the bellows to correct the displacement of the lip portion structure 12 due to the resin pressure.

In this case, basically, the flow rate is large when the gap amount of the nozzle portion is large, and the flow rate is small when the gap amount is small, and this relationship is a monotonically increasing function. This relationship can be grasped by measuring in advance. Further, since the gap amount of the nozzle is detected as a certain proportional value by the displacement sensor 15 of the drive unit structure 3, it is possible to detect a change in the gap amount by measuring the relationship in advance. Therefore, the film pressure can be controlled by controlling the amount of displacement between the main body structure 1 and the drive unit structure 3 by the displacement sensor 15.

According to the present invention, the deformation error of the lip portion due to the resin pressure is corrected, and the lip opening can be controlled with high accuracy.

The displacement sensor 15 is not particularly limited to an eddy current method, a capacitance method, an optical fiber method, a contact method, or the like.

Although the present invention invents the driving of the T-die lip, it can also be used as a precision driving machine for various precision machines such as a processing machine, a three-dimensional measuring machine, and a semiconductor manufacturing apparatus.

(Effect) Since the driving part is formed by the expansion and contraction action of the bellows, the response is extremely excellent. By the way, the time constant is 10 ~
In contrast to 20 minutes, this is less than 1 second in the present invention.

Since the expansion and contraction of the bellows is controlled by the elastic deformation of the nozzle portion from the drive portion structure through the nozzle portion structure, there is almost no hysteresis and a high drive resolution.

Since the driving unit is divided, it is possible to provide a structure of the driving unit having a small degree of interference with another adjacent driving unit.

In addition to the control method that drives the drive unit structure by the expansion and contraction of the bellows, the displacement of the lip due to resin pressure is detected by a displacement sensor, and this is fed back to control the lip opening, so higher accuracy is achieved. Control became possible.

[Brief description of the drawings]

FIG. 1 is a perspective view of a T-die lip. FIG. 2 is a view on arrow II of FIG. FIG. 3 is a bottom view of FIG. FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG. 5 is a view on arrow V in FIG. FIG. 6 is a view taken in the direction of the arrow VI. FIG. 7 is a view for explaining a state of displacement of a lip portion due to a resin pressure. FIG. 8 is a block diagram of a lip opening control system. In the figure: 1... Body structure 2 (2a, 2b)... Bellows 3... Drive unit structure 4... Seal 5... Seal 6... Bolt 7. 9b, 9c ... air passage, 10 ... air supply port 11 ... elastic deformation part, 12 ... lip part structure 13 ... lip part, 14 ... division groove 15 ... displacement sensor, 16 ... wiring

Claims (1)

(57) [Claims] 1. A body structure (1), a plurality of bellows (2) disposed on the side of the body structure (1), and an upper portion fastened to each bellows (2), and a lower portion having a lip portion. It comprises a bellows (2) fastened to the structure (12) and a drive structure (3) connecting the lip (13), and the drive structure (3) is in the width direction of the lip (13). And a displacement sensor (15) for detecting the displacement of the lip (13) due to the resin flow pressure above the divided drive unit structure (3) corresponding to the plurality of bellows (2). ) Is provided, and the detected value of the displacement sensor (15) is fed back to compare the detected value of the displacement sensor (15) with the target displacement amount,
Convert the compared positive / negative value to gas pressure Pa with a voltage converter,
A structure for correcting a deformation error of a T-die lip drive unit, wherein the gas pressure Pa is supplied to the bellows (2) to control the lip opening.