JPH03281216A - Allocation setting method of sheet thickness measuring position and lip position in extrusion - Google Patents

Abstract

PURPOSE:To easily perform allocation setting of both thickness measuring position and lip piece at high precision by allotting and setting the correspondent relation of the thickness measuring position in the width direction of a plastic sheet in the place for measuring sheet thickness and a plurality of lip pieces on the basis of an expression shown in an experimentally obtained rational function. CONSTITUTION:Thickness in the width direction of plastic in the place for measuring sheet thickness is measured. The relation of relative position of both the position Xi of a lip piece and the thickness measuring position Xi in the width direction receiving the effect of this lip piece is experimentally obtained and approached by a rational functional expression. In the expressions (1) - (3), the position data X0 - Xn are already known and the neck-in amount X0 is measured at every time for measuring thickness because a thickness measuring instrument is moved in the width direction of the plastic sheet from position 0. When these values are obtained, calculation is performed in the order of x1, x2, x3,.... Since the thickness measuring positions correspondent to the position data X1, X2, X3,... of lip pieces are calculated, it can be easily understood that the thickness measuring position corresponds to any lip piece.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an extrusion molding machine for plastic sheets such as laminate films, and in particular, the present invention relates to an extrusion molding machine for plastic sheets such as laminate films, and in particular, extrusion molding machines for extrusion molding of plastic sheets such as laminate films, etc. When measuring the thickness in the width direction of
The present invention relates to an allocation setting method for associating measurement positions with a large number of lip pieces arranged in parallel in the width direction of a die.

(Conventional technology) This type of extrusion molding machine is shown in Figure 2.

The first to nth lip pieces 11-] to 1 in the width direction of the die 10
1-n are installed in parallel. The plastic sheet 12 extruded from the die 10 is sent to a cooling roll 13 and is pressed against a base material 5 supplied from another system to form a laminate film 16. The opening degree between each lip piece and the fixed lip can be adjusted by a mechanism called a die bolt (not shown) provided in a one-to-one correspondence, and this allows for arbitrary adjustment in the width direction of the plastic sheet 12. The thickness of the position can be adjusted. Note that a mechanism other than the die bolt, such as a pneumatic type or a heat bolt, may be used. There are also types of lip pieces that are independently movable and types that allow adjacent lip pieces to interfere with each other.

In any case, the mechanism of die bolt etc.

Drive control is performed by a drive control device 17. In particular, when performing automatic thickness control, it is necessary to measure the thickness of the plastic sheet 12 in the width direction at a position close to the cooling roll 13. In addition, it is necessary to perform layout settings that associate the relative positional relationship between the thickness measurement position and each lip piece in one width direction.

This ratio (=l setting) is also important when performing a flow analysis of the plastic extruded from the die 10 when the opening degree of the lip piece is adjusted.

(Problem to be Solved by the Invention) However, the plastic sheet 12 extruded from the die 10 contracts at both ends while reaching the cooling roll 13. This is called a neck-in phenomenon, and is one of the factors that makes the above-mentioned allocation setting difficult. For this reason, proposals have been made to improve the accuracy of 1-allocation setting in order to improve the accuracy of controlling the thickness of plastic sheets, but the reality is that a simple and highly accurate allocation setting method has not yet been established. Due to these circumstances, thickness control is usually performed by one person, taking skill and experience into consideration.

From the above points of view, two objects of the present invention are to provide a layout setting method that can easily and accurately perform layout settings that associate the relative positional relationship between the thickness measurement position and the lip piece in the width direction of a plastic sheet. It's about doing.

The present invention also includes: It is an object of the present invention to provide a layout setting method suitable for a control system that automatically controls the distribution of sheet thickness in the width direction by combining a lip piece drive mechanism and a plastic sheet thickness measuring device.

(Means for Solving the Problems) The present invention provides an extrusion molding machine that continuously extrudes a plastic sheet from a die having a plurality of lip pieces, at a sheet thickness measurement point set on a conveyance path of the plastic sheet. The correspondence relationship between the thickness measurement position in the width direction of the plastic sheet and the plurality of lip pieces is arranged in a window based on a formula expressed by a rational function determined experimentally in advance. This is a characteristic method of setting the allocation of sheet thickness measurement positions and lip positions in extrusion molding.

When the position of the predetermined part of the lip piece is X, (t is a positive integer from O to n), and the thickness measurement position in the width direction of the plastic sheet is χ, the rational function is X.

It is expressed as n>i>n/2 /χO・ time, χO is neck-in amount) (However, it is expressed as X=(X −X, )/χ.).

1 (Example) An example of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 2, when the degree of opening of the lip piece at an arbitrary position is adjusted, the thickness at the sheet thickness measurement point at the position corresponding to the lip piece 7' in the width direction increases or decreases in accordance with the degree of opening. In the present invention, by sequentially opening the lip pieces starting from 111 and measuring the thickness in the width direction of the plastic sheet at a fixed location where the sheet thickness is i+, the position of the lip piece and the width direction affected by the lip piece are determined. The relative positional relationship with the thickness measurement position is experimentally determined, and this relative positional relationship is approximated by the auto-expansion formula described below.

Figure 1 shows the position X of a predetermined part of the lip piece (here, the left end in Figure 1) in the experiment described in Section 2, (i is 11 from 0 to n),
(an integer of ) and the measurement position χ in the width direction at the sheet thickness measurement point that is a distance away from here. As is clear from the figure.

At a fixed location where the sheet thickness is 41, both ends of the plastic sheet are squeezed by a dimension χ0 due to the neck-in phenomenon.

As the distance approaches the center, the width between the measurement positions becomes approximately equal to the width of the lip piece. Note that the fixed location for the sheet thickness Δ1 may be any location where the aperture due to the neck-in phenomenon settles to a constant value, and even in the case of a laminate film as shown in FIG. 2, the thickness of the base material 15 is already known. , the thickness of the plastic sheet part can be easily measured.

Experimental data 2 obtained as follows: data at the position X of a predetermined portion of the lip piece, data at the measurement position χ of the sheet thickness, and neck-in amount χ. Based on 1, for example by least squares method, i=o.

Except for the case of i=n, the rational function formula can be calculated as follows.

(at l-0) χ0=χo, x=.

(n/2 ≧ i χ 4 χ・ 1 〉O) ...(1) ([1〉 i　　　　　　n　/2 time) however.

X=X.

/χ0 ...(2) However, X-(X-X,)/χ.

1 (When i=n) In the above equations (1) to (3), 1 position data X.

Since the measuring device moves from position 0 in FIG. 1 in the width direction of the plastic sheet, the actual thickness is measured each time. Once these values are known, χ1. χ2. Since the calculations are performed in the order of χ3, etc., and the position data of the lip piece is calculated, it is possible to easily know which lip piece corresponds to the thickness measurement position.

As described above, the relative positional relationship between the lip piece and the thickness measurement position in the width direction of the plastic sheet can be known, so resin flow analysis associated with opening and closing of any lip piece can be performed easily and with high accuracy. I can do it. Also, by measuring the thickness of the plastic sheet during the production operation of laminated film, the operator can
Dipol lip piece with a definite result!・You can accurately and immediately know how much adjustment to make. Furthermore, the data at each measurement position is combined with the detection signal.
By inputting data to the drive control device] 7 shown in FIG. 2, the drive control device 17 can control the die bolts of each lip piece to automatically control the distribution of sheet thickness in the width direction.

(Effects of the Invention) As explained above, according to the present invention, the assignment of the position of the lip piece in the extrusion molding machine and the thickness measurement position in the width direction of the plastic sheet extruded from the die can be easily and accurately set. I can do what I want to do. Therefore, the layout setting method 0 according to the present invention is an automatic thickness control method that automatically controls the opening degree of the lip piece based on the thickness measurement result at an arbitrary position.

Ideal for performing resin flow analysis by opening and closing lip pieces at arbitrary positions.

[Brief explanation of drawings]

Fig. 1 is a diagram schematically showing the extrusion molding machine to which the present invention is applied in a portion near the die, and Fig. 2 is a diagram showing the position of the lip piece and the width direction of the plastic sheet in order to explain the present invention in detail. The figure which showed the relationship with a thickness measurement position. In the figure, 10...Die, 11-1 to 11-n...Lip piece, 12...Plastic sheet, 13...Cooling roll, 15...Base material, 16...Laminate film. 17... Drive control device.

Claims (1)

[Claims] 1) In an extrusion molding machine that continuously extrudes a plastic sheet from a die having a plurality of lips, the width direction of the plastic sheet at a sheet thickness measurement point set on the conveyance path of the plastic sheet. The sheet thickness measurement in extrusion molding is characterized in that the correspondence between the thickness measurement positions and the plurality of lip pieces is assigned and set based on a formula expressed by a rational function determined experimentally in advance. How to set the allocation between position and lip position. 2) In the layout setting method according to claim 1), the position of the predetermined portion of the lip piece is set to Xi (i is a positive integer from 0 to n).
, when the thickness measurement position in the width direction of the plastic sheet is χi, the rational function is: When n/2≧i>0, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, X=X_i/χ_0 , χ_0 is the neck-in amount)
When n>i>n/2, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, X = (X_n - X_i) / χ_0) A sheet in extrusion molding characterized by How to set the allocation of thickness measurement position and lip position.