JPH03286830A - Sheet thickness-controlling method in extrusion molding machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an extrusion molding machine, and particularly relates to an extrusion molding machine, and in particular to a plastic sheet and a laminate film made by laminating a base material on this plastic sheet (hereinafter simply referred to as a plastic sheet).
The present invention relates to a sheet thickness control method that measures the thickness in the width direction of a plastic sheet extruded from a die during molding and controls the sheet thickness based on this measured value.

(Conventional technology) An example of an extrusion molding machine will be explained with reference to FIG.

A plurality of lip pieces 11-1 to 1l-n are provided in the width direction of the die 10.
(n is a natural number). Each lip piece can be driven by a mechanism called a die bolt (not shown), and the opening degree of the resin outlet can be adjusted for each lip piece. This mechanism may be replaced by a pneumatic type, a heat bolt, etc. in addition to the die bolt. The die 10 is mounted on a moving carriage 12 and is movable in the width direction. die 10
The plastic sheet 13 extruded from the cooling roll 15 is pressed onto the base material 14 supplied from another system, and
The laminated film 16 is conveyed to a take-up roll (not shown).

A sheet thickness detection device W20 is arranged in the middle of the conveyance path of the laminate film 16. Sheet thickness detection device 20
is a sheet thickness sensor 21 and a laminated film 1.
It consists of a sensor drive mechanism 22 that drives in the width direction of 6,
The thickness distribution of the laminate film 16 in the width direction is measured. The detection signal from the sheet thickness sensor 21 is supplied to the sheet thickness driving side avtlt17. The sheet thickness drive control bag at17 controls the thickness of the plastic sheet by driving and controlling the die bolts corresponding to each lip piece in accordance with the detection signal from the sheet thickness sensor 21.

(Issue 1i to be solved by the invention) By the way, in this type of extrusion molding machine, both ends of the plastic sheet 13 extruded from the die 10 or the cooling roll 15
shrink before reaching . A so-called neck-in phenomenon occurs. For this reason, the installation of the sheet thickness detection device 120 is
In some cases, the width of the laminate film 16 is greater than the width of the die 10.
is narrower than the width of Therefore, the sheet thickness sensor 21
The sheet thickness measured at a certain measurement position is lip piece 11.
In order to know which of -1 to 11-n it corresponds to, measure the amount of neck-in in advance.

It is necessary to align one end of the die 10 in the width direction with the measurement start position of the sheet thickness sensor 21.

However, the die 10 may be moved in the width direction by the moving cart 12. In this case, the die 10 is returned to its original position, but it is not necessarily returned to its original position accurately. In this case, a deviation occurs in the correspondence between each lip piece and the position measured in the width direction by the sheet thickness sensor 21, resulting in an error in thickness distribution control in one width direction.

Under these circumstances, conventionally, the operator has adjusted the drive of each lip piece by monitoring the sheet thickness measurement data and taking skill and experience into account.

In consideration of the above points, one object of the present invention is sheet thickness control that can accurately set the correspondence relationship between each lip piece and the #1 fixed position in the width direction of the sheet thickness sensor even if the position of the die changes. The goal is to provide a method.

(Means for Solving the Problem) The present invention has a plurality of lip pieces arranged in parallel in the width direction of the die,
An extrusion molding machine comprising a thickness control means for controlling the sheet thickness by driving the lip piece based on a detection signal of a sheet thickness sensor that measures the thickness of the sheet extruded from the die in its width direction, The extrusion molding machine is characterized in that the thickness control means includes a correction means for correcting the correspondence relationship between the plurality of lip pieces and the measurement position of the sheet thickness sensor in the width direction of the sheet at the time of starting extrusion molding. This is a sheet thickness control method for

The correction means includes a first step of changing the degree of opening of the die in at least two predetermined lip pieces among the plurality of lip pieces, and two positions of thickness changes that appear in the sheet by changing the degree of opening. a second step of estimating based on a predetermined formula; a third step of detecting the positions of two thickness changes that appeared on the sheet due to the change in the opening degree; a fourth step of calculating a neck-in amount by performing calculations according to the predetermined formula using the position of change; and a fourth step of performing the same process as the second step using the calculated neck-in amount; and a fifth step of correcting and calculating the two thickness change positions, wherein the two correction calculation positions calculated in the fifth step and the two thickness change positions detected in the third step are equal. The above 4. It is characterized by repeating the fifth step.

Note that the predetermined formula is as follows.

χ I 1 χ 1 (X, -X, ,) where i is an integer of Q-11 (n is a natural number), χ0 is the amount of neck-in, Xi is the center position of the i-th lip piece, and χ is the i-th The sheet thickness measurement position corresponding to the lip piece is used.

(Function) The present invention focuses on the fact that there is a correlation expressed by the above equation between the plurality of lip pieces and the sheet thickness measurement position in the width direction at the sheet thickness measurement location. The above formula was derived as a result of the inventor's repeated experiments on the relationship between each lip piece and the measurement position of the sheet thickness in the width direction.6
This invention is detailed in ``Method for Allocation Setting of Sheet Thickness Determined Position and Lip Position in Extrusion Molding'' filed on the same day as the present invention.

If the die deviates in its width direction, since the measurement range of the sheet thickness sensor is fixed, the relationship between each lip piece and the width direction measurement position of the sheet thickness sensor will also be deviated.

However, this deviation is the neck-in amount χ in the above equation. It will be corrected by correcting. In other words, the neck-in is performed so that there is no discrepancy between the two thickness change positions detected in the third step and the two corrected values calculated in the fifth step with respect to the two predetermined lip pieces. The process of correcting the amount is repeated, and based on the neck-in amount when the deviation is eliminated, the subsequent allocation of the width direction measurement position of the sheet thickness sensor for each lip piece is set.

(Example) An embodiment of the present invention will be described below.

Referring to FIG. 1, in addition to the conventional configuration shown in FIG.
It is characterized by having It30.

The correction device 30 includes a peak value calculation calculation device af31 that performs calculations based on a predetermined formula to be described later, and calculates a peak value of change in sheet thickness based on a detection signal from the sheet thickness sensor 21.

A correction et calculation device that outputs a correction value regarding the neck-in amount to the sheet jv kneading drive control device 17 based on the output from the peak value calculation device 31, and returns the correction data of the neck-in amount to the peak value calculation calculation device 31. It consists of 32 pieces.

Next, the operation will be explained with reference to FIGS. 2 and 3.

The correction operation in the correction device 30 starts with the start of the extrusion molding operation.

In the correction operation, first, in step S1, two predetermined lip pieces 1l-k (kth), 1
The resin outlet of the die at 1-m (mth) is narrowed (
Figure 2 a). Then, the sheet thickness detection device! The thickness of the laminate film reaching 20 also becomes thinner in two places (
Figure 2 b).

Here, the distances from the left end of the die 10 in the figure to the right end of the lip piece 11- and the right end of the lip piece 11-m are respectively I.
If X k HX m, then lip piece 11-, 11-
The center position WXr, X2 of m is X, sw (X=
X*-r)/2. X2 ” (X, -X, -r)/
It is represented by 2.

First, in step S2, the peak value calculation arithmetic unit 31 calculates, based on the detection signal from the sheet thickness sensor 21, the first sheet whose thickness has reached its peak value. second detection position χ1′,
Find χ2' (see Figure 2C for both). The peak value calculation calculation unit ft31 then proceeds to step S3, and calculates the lip piece 11-k.

11-m center position x,,x2. Using the initial value χ0 of the neck-in amount, the lip piece 11-
The first estimated value χ7 of the width direction measurement position corresponding to k. A second estimated value χ2 of the width direction measurement position corresponding to the lip piece 11-m is calculated.

χ　I　　5　χ　Direct (X, -X, -,) (1) However, X is the center position of the i-th lip piece.

χ1 is the measurement position in the width direction of the sheet thickness sensor corresponding to the i-th lip piece.

Here, if the position of the die 10 is shifted in the width direction, a shift occurs in the relationship between each lip piece and the width direction measurement position of the sheet thickness sensor already associated with each lip piece. estimated value χ, and first detected position χ,
The second estimated value χ2 and the second detected position χ2' do not match (FIG. 2C). The peak value calculation arithmetic unit 31 compares χl and χ1 and χ2 and χ2 in step S4.

If they do not match, the first step. The data of the second detected positions χ1' and χ2 are output to the correction calculation device 32.

The correction calculation device 32 receives the first . Data of second detection positions χ1 and χ2 and center position χ1. Using the data of χ2, the neck-in amount is corrected to the neck-in amount χ based on equation (1) in step S5. ' and returns it to the peak value calculation arithmetic unit 31.

After that, the operation returns to step S3, and the peak value calculation arithmetic unit t31 calculates the returned corrected neck-in amount χ. The first estimated value χ is calculated using equation (1).

An estimated value obtained by correcting the second estimated value χ2 and an estimated value obtained by correcting the second estimated value χ2 are respectively calculated.

The peak value calculation calculation device 31 and the correction calculation device 32 perform the above operations, that is, steps 83 to S5, in the first detection position and the first estimated value, and in the second detection position and the second estimated value, respectively. As shown in Figure d.

Repeat until equal. The fact that the first detected position and the first estimated value are equal, and that the second detected position and the second estimated value are equal means that the optimum neck-in amount has been calculated to correct the error caused by the deviation of the die 10. It means that. The correction calculation device E32 provides the optimum neck-in amount obtained in one or more ways to the sheet thickness drive fi4m device 17. This completes the correction operation.

The sheet thickness drive control device 17 performs reallocation settings between each lip piece and the width direction measurement position of the sheet thickness sensor 21 based on the given optimal neck-in amount. Thereafter, the sheet thickness drive control device 17.

By driving and controlling the die bolts of each lip piece based on the detection signal from the sheet thickness sensor 21, the thickness distribution in the width direction of the laminate film 16 is controlled.

The present invention is not limited to the above embodiments, and various modifications are possible. For example, a sheet thickness sensor is moved by a drive mechanism.

Instead of the so-called scanning type, it may be made of an array of detection elements arranged in the width direction of the sheet.

Further, the lip pieces provided on the die are not limited to so-called non-interference type lip pieces that can be driven independently, but may also be interference type lip pieces that interfere with each other.

(Effects of the Invention) As described above, according to the present invention, a means for correcting the relationship between the plurality of lip pieces and the position measured in the width direction by the sheet thickness sensor is provided.

Even if the die is misaligned in the width direction, the relationship between each lip piece and the measurement position in the width direction of the sheet thickness sensor can be quickly and accurately allocated. Therefore, according to the present invention, there is no need for an operator to control the sheet thickness while monitoring sheet thickness measurement data, and the sheet thickness can be controlled with high precision.

17 is a sheet thickness drive control device.

20 is a sheet thickness detection device, 21 is a sheet thickness sensor, 2
2 is a sensor drive mechanism, 30 is a correction device, 31 is a peak value calculation calculation device, and 32 is a correction calculation device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of the main parts of an extrusion molding machine embodying the present invention, and FIG. 2 is a diagram showing detection signals from a lip piece and a sheet thickness sensor to explain the operation of a correction device according to the present invention. A diagram showing the relationship between FIG. 3 is a flowchart for explaining the progress of the operation of the correction device according to the present invention, and FIG. 4 is a schematic configuration diagram of the main parts of a conventional extrusion molding machine. In the figure, 10 is a die, 11-1 to 11-n are lip pieces, 1
2 is a moving trolley, 13 is a plastic sheet, 14 is a base material, 15 is a cooling roll, 16 is a laminate.

Claims (1)

[Claims] 1) A plurality of lip pieces are arranged in parallel in the width direction of the die, and the lip pieces are arranged in parallel in the width direction of the die, and the lip pieces are adjusted based on a detection signal of a sheet thickness sensor that measures the thickness of the sheet extruded from the die in the width direction. In the extrusion molding machine, the thickness control means controls the sheet thickness sensor in the width direction of the plurality of lip pieces and the sheet at the start of extrusion. A sheet thickness control method for an extrusion molding machine, characterized by comprising a correction means for correcting a correspondence relationship with a measurement position. 2) In the sheet thickness control method according to claim 1, the correction means includes a first step of changing the degree of opening of the die in at least two predetermined lip pieces among the plurality of lip pieces; a second step of estimating, based on a predetermined formula, the positions of the two thickness changes that appear in the sheet due to the change in the opening degree; and detecting the positions of the two thickness changes that appear in the sheet due to the change in the opening degree; and a fourth step of calculating the amount of neck-in by calculating according to the predetermined formula using the detected two thickness change positions.
and a fifth step of performing the same process as the second step using the calculated neck-in amount to correct and calculate the positions of the two thickness changes, and calculating by the fifth step. Sheet thickness control in an extrusion molding machine, characterized in that the fourth and fifth steps are repeated until the two corrected calculated positions and the two thickness change positions detected in the third step are equal. method. 3) In the sheet thickness control method according to claim 2), the predetermined formula includes ▲a mathematical formula, a chemical formula, a table, etc.▼where, i is an integer from 0 to n (n is a natural number), and x_0 is a neck In amount, X_i is the center position of the i-th lip piece, x_
A sheet thickness control method in an extrusion molding machine, characterized in that i uses a sheet thickness measurement position corresponding to the i-th lip piece.