JPS6135927A - Die bolt controlling device of t die for extrusion molding of plastic sheet and the like - Google Patents

Abstract

PURPOSE:To enable to automatically control the desired profile by a constitution wherein the angular positions of respective die bolts to control the lip gap of a T die for extrusion molding are automatically set by employing a die bolt controlling device adapting a CPU. CONSTITUTION:A controlling unit 52 is driven by a servo motor 60 so as to place a pulse motor 54 at the neutral position determined base upon the data of the memory 66 of a CPU and, after that, to engage a socket 48 with a die bolt 36 by means of a solenoid valve 80. The bolt 36 is turned through an angle of an effective angle plus alpha by means of the motor 54 based upon the operational control instruction of the CPU64 and, after that, returned by alpha as an angle of play toward the neutral position. The resultant angular position of the socket 48 is detected by a detector 82 and stored renewedly in the memory 66. The operation mentioned above is empolyed to all the bolts 36. When the extrusion molding state is established by setting the gap 42 between the lips 32 and 34 of a T die, automatic profile control is performed based upon the data sent from a scanning thickness meter 46. Consequently, the desired die bolt controlling device of T die for extrusion molding is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an adjustment device for a T-die for extrusion molding a plastic sheet, etc., and in particular to a T-die adjustment device formed by a slide lip or choke bar and a fixing member facing the same. The present invention relates to an operating device for automatically adjusting the position of a plurality of die bolts provided in the width direction of the slide lip or the like in a pattern of flow path gaps.

[Prior art and its problems]

Conventionally, when extrusion molding a plastic sheet or the like, a T-die constructed as shown in FIG. 4 is known as a T-die constructed so as to be able to adjust the thickness unevenness in the width direction of the sheet. That is, FIG. 4 shows a slide lip type T-die configured to use a slide lip to adjust the gap between the gouers for extrusion molding a sheet or the like. In FIG. 4, reference numeral 10 indicates a fixed lip and 12 a sliding lip, which are extruded with a lip gap 14 formed by these lips 10.degree. The thickness of the plastic sheet is specified. However, this slide lip 12 is provided with a plurality of die bolts 16 in the width direction, and is configured to move these die bolts 16 respectively along the slide surface 20 of the movable die 18 to adjust the lip gap 14. (See Figure 5).

However, in conventional extrusion molding machines that use T-dies equipped with this type of adjustment mechanism, a scanning thickness needle is used to measure the thickness by reciprocating the measuring head in the width direction of the plastic sheet being extruded. An automatic profile control system is adopted in which the die bolt is operated by a servo motor or the like to set the lip gap of the T-die at an appropriate position.

However, in this case, smooth engagement of each die bolt with a coupling means for operating the die bolt becomes an unavoidable important issue in order to improve control characteristics. From this point of view, various proposals have been made to facilitate engagement by modifying the shape of the head of the die bolt and the socket of the coupling means that engages with the head, such as chamfering. However, these conventional coupling means have the following problems.

(1) A clutch mechanism is required to prevent unnecessary rotation of the die bolt due to the torque generated during engagement.

Further, in order to eliminate play during engagement, it is necessary to separately provide a low torque motor. This not only complicates the configuration, but also increases the equipment space and manufacturing costs.

(2) Even if the shape of the engaging portion is modified, it is not possible to engage each die bolt in a straight manner. Therefore, an extra correction operation for engagement is required, resulting in a disadvantage that the operation speed, that is, the work efficiency is reduced.

(3) Although the socket of the coupling means may be structured to be rotatable by a certain angle with respect to the drive shaft, the problems of (1) and (21) above cannot be solved in this case as well.

[Purpose of the invention]

An object of the present invention is to achieve smooth engagement with a coupling means for adjusting a die bolt with a simple configuration and control operation, and to achieve automatic profile control in an extrusion molding machine for plastic sheets etc. with high precision and high efficiency. To provide a die bolt operating device for a T-die for extrusion molding of plastic sheets, etc., which can be realized in the following manner.

[Key points of the invention]

The die bolt operating device for a T-die for extrusion molding of plastic sheets, etc. according to the present invention can adjust the lip gap by operating a plurality of die bolts using an automatic profile control device, thereby adjusting the thickness of the extruded plastic sheet, etc. In an extrusion molding machine equipped with a T-die, means for detecting the current angular position of each die bolt and sequentially updating and storing this data, and calculating a profile control signal for each die bolt due to thickness variation based on the updated and stored data. and a socket for engaging and rotating a predetermined die bolt; the socket is pressed against the head of a predetermined die bolt and engaged with the die bolt while rotating; and means for controlling the die bolt profile.

In the die bolt operating device described above, the means for controlling the profile of the die bolt based on the calculation means includes a pulse motor that rotationally drives the socket, a fluid pressure cylinder that moves the socket forward and backward relative to the die bolt, and a fluid pressure cylinder that moves the socket toward a predetermined die bolt. On the other hand, the configuration may include a servo motor that performs positioning.

In addition, a scanning thickness gauge is provided for the plastic sheet etc. extruded from the T-die, and the thickness data obtained by this thickness gauge is processed by a calculation means together with data regarding the current angular position of each die bolt, It is preferable that the rotation angle signal is obtained as a profile control signal for a required die bolt.

[Embodiments of the Invention] Next, embodiments of a die bolt operating device for a T-die for extrusion molding of plastic sheets, etc. according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the configuration of a die bolt operating device and its control system according to the present invention. In FIG. 1, reference numeral 3
0 indicates a T-die which is connected to an extrusion molding machine and continuously extrudes the plastic sheet S in the same manner as in FIG. This T-die 30 includes, for example, a fixed ring 132 and a slide lip 34, and the slide lip 34 is provided with a plurality of die bolts 36 in the width direction, and these die bolts 3
6 relative to the wall surface 40 of the movable die 38, the plastic sheet S to be extruded is
The lip gap 42, which defines the thickness of the lip gap 42, can be configured to be adjustable. The plastic sheet S extruded from the lip gap 42 of the T-die 30 is sent out via a cast roll 44 as appropriate, and the plastic sheet S
A measuring head of a scanning thickness gauge 46 is provided in a part of the delivery path.

On the other hand, a drive mechanism 50 is provided on the head of the die bolt of the T-die 30 and includes a socket 48 as a coupling means that engages with the head of the die bolt. This drive mechanism 50 has an operation head 52 that holds the socket 48, and a socket drive pulse motor 54- for this operation head 52.
A fluid pressure cylinder 56 for pushing the socket, a socket engagement detector 5B, and a positioning servo motor 6 that moves the operation head 52 so that the socket 48 is positioned opposite to the plurality of die bolts 36 attached to the T-die 30 side.
0 and 0 are respectively provided. Note that a detection end portion 62 for performing a detection operation of the socket engagement detector 58 is built inside the socket 4B. In order to perform automatic profile control on the T-die 30 of the extrusion molding machine, the drive mechanism 5.0 configured in this manner calculates and controls each of the controllers using a computer system based on measurement data from the scanning thickness gauge 46. Configure it to do so. That is, in the embodiment shown in FIG.
U64, internal storage device 66, keyboard 68, external storage device 70, and CRT display 72 are connected and arranged, respectively.

Therefore, the measurement signal from the scanning thickness gauge 46 is input to the CPU 64 via the interface 74, and the detection signal from the socket engagement detector 50 is also input to the CPU 64. On the other hand, the above C
From the PU 64, predetermined arithmetic control commands are sent to the socket drive pulse motor 54 via the pulse motor controller 76, to the positioning servo motor 60 via the servo motor controller 78, and further via the electromagnetic switching valve 80. and is supplied to the socket pushing fluid pressure cylinder 56. In addition, in this embodiment, a position detection device such as a rotary encoder 1) 8 is used for the socket drive pulse motor 54.
2 is provided to detect the rotational position of the pulse motor 54 and send this detection signal to C via the pulse motor controller 76.
The configuration is such that the data is input to the PU 64 as arithmetic processing data.

Further, in the present invention, the geometric dimensions of the engagement between the head of the die bolt 36 and the socket 48 are set as follows. FIG. 2 shows the engagement relationship between the regular hexagonal die bolt head 36a and the engagement hole 48a of the socket 48 in a neutral position, and FIG. 3 shows the engagement relationship between the die bolt head 36a and the socket 48 when the socket 48 is in the driven state. This shows the engagement relationship with the hole 48a. From the relationship shown in FIG. 2, the relationship between the gap C between the die bolt head 36a and the engagement hole 48a of the socket 48 and the play angle α until engagement is generally expressed by the following equation.

However, n = number of angles of the die bolt head 36a. For example, in the embodiment shown in FIG. 2, n = 6, c = 0.3 m
, if a=9.5 tx, β force is 27゛, α
It becomes 3° to

Next, basic control operations of the apparatus of the present invention having the above configuration will be explained.

(1) First, the positioning servo motor 60 for moving the operating unit 2 52 relative to the die bolt 36 is activated, and the socket 48 is positioned at a position facing a predetermined die bolt 36.

(2) The socket driving pulse motor 54 is operated to position the socket 48 at a substantially neutral position with respect to the die bolt 36 (see FIG. 2) based on data stored in the internal storage device 66 of the computer system.

(2) Activate the electromagnetic switching valve 80 to move the socket 48 forward and engage the head of the die bolt 36.

■ The socket drive pulse motor 54 is activated, and after rotating the die bolt 36 (effective angle + α) based on the calculation control command, the head of the die bolt 36 and the socket 48 are returned to the neutral position by reversing the play angle α. return. During this time, the angular position of the socket 48 is detected by a position detector 82 or the like,
This data is stored in the computer system's internal storage device 66.
Updated and stored as the current value.

(2) Activate the electromagnetic switching valve 80 to move the socket 48 back and disengage it from the die bolt 36.

In the apparatus of the present invention, the above-mentioned operations (1) to (4) are appropriately performed on each die bolt 36 to adjust the lip gap of the T-die, and the extrusion molding machine is operated to continuously extrude a plastic sheet of a predetermined thickness.

In addition, in the extrusion molding state of the plastic sheet,
Automatic profile control can be realized by repeating the operations ① to ② for the required die bolts 36 based on the measurement data of the scanning thickness gauge.

In particular, in the present invention, in the control operation (①) above,
The socket 48 is held in contact with the head of the die bolt 36 by the fluid pressure cylinder 56 at a pressure that can maintain the friction torque to a minimum, and in this state, the pulse motor 54 is operated to rotate the socket 48 in the direction of tightening the die bolt 36. let

As a result, the socket 48 rotates in sliding contact with the head of the die bolt 36, and engagement in its neutral position is achieved within a rotation angle of 360°/n. At this time, socket 4
8 moves forward, and the state of engagement with the die bolt 36 is confirmed by the engagement detector 58. Also, the engagement between the socket 48 and the die bolt 36 at this time! Since @ is indeterminate, if the socket 4B is further rotated by at least 2α or more, the engaged state as shown in FIG. 3 will be achieved. The angular position of the dipole 360 at this time is detected by the position detector 82 or the like as 360°/n from the reference position, and this data is updated and stored in the internal storage device 66 of the computer system.

Thereafter, by reversing the socket 48 by α, the state of engagement with the die bolt 36 can be brought to the neutral position as shown in FIG. 2, and the socket 48 can be easily retracted from the die bolt 36. can. In addition, Daiboru 3
The current angular position of 6 can be easily detected by using a computer system to count the number of pulses that command the drive of the pulse motor 54 that rotates the socket 48 when the socket 48 is engaged with the die bolt 36.

[Effects of the Invention] As is clear from the embodiments described above, according to the present invention,
In an extrusion molding machine for plastic sheets, etc. that performs automatic profile control with adjustable thickness, the lip gap of the T-die for extrusion molding is adjusted.Each die bolt is automatically adjusted.The current angle of each die bolt is determined by an operating device using a computer system. The position is updated and memorized, and the die bolt to be controlled and the socket of the device for operating the die bolt are always kept in the neutral position, and smooth and quick engagement can be realized. Therefore, according to the device of the present invention, automatic profile control is achieved quickly and reliably at low cost without employing flexible structures for clutches, torque motors, sockets, special processing of engaging parts, etc. as in the past. can do.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a control system showing an embodiment of the die bolt operating device for a T die for extrusion molding of plastic sheets, etc. according to the present invention, and FIGS. 2 and 3 show the head and socket of the die bolt in the present invention. FIG. 4 is a perspective view of a main part of a conventional slide lip type T-die, and FIG. 5 is a vertical cross-sectional view of a main part of the T-die shown in FIG. 4. 30, T-die 321. fixed lip 340
．． Slide lip 366. Daibolt 381. Movable side die 401. Wall surface 420. lip gap
440. Cast roll 460. scanning thickness gauge
48. , socket 500. Drive mechanism 520.
Go to operation 540. Socket driving pulse motor 560. Socket pushing fluid pressure cylinder 580. socket engagement detector

Claims (3)

[Claims] (1) In an extrusion molding machine equipped with a T-die that can adjust the lip gap and the thickness of the extruded plastic sheet etc. by operating multiple die bolts using an automatic profile control device, the current angular position of each die bolt means for detecting and sequentially updating and storing this data; means for calculating a profile control signal for each die bolt due to thickness variation based on the updated and stored data; and means for engaging a required die bolt and rotating it. and means for pressing the socket into contact with the head of a predetermined die bolt and engaging the die bolt while rotating the socket, and then executing profile control of the die bolt based on the calculation means. Die bolt operating device for T-die for extrusion molding of plastic sheets, etc. (2) In the die bolt operating device according to claim 1, the means for executing profile control of the die bolt based on the calculation means includes a pulse motor that rotationally drives the socket, and a fluid that moves the socket forward and backward with respect to the die bolt. A die bolt operating device for a T die for extrusion molding of plastic sheets, etc., comprising a pressure cylinder and a servo motor for positioning a socket with respect to a predetermined die bolt. (3) In the die bolt operating device according to claim 1, a scanning thickness gauge is provided for the plastic sheet etc. extruded from the T-die, and the thickness data obtained by the thickness gauge is calculated. A die bolt operating device for a T-die for extrusion molding of plastic sheets, etc., which comprises calculating and processing data on the current angular position of each die bolt together with means to obtain a rotation angle signal as a profile control signal for a required die bolt.