JPH05116201A - Extruding equipment for synthetic resin pipe - Google Patents

Abstract

PURPOSE:To always produce a synthetic resin pipe free from deviation of wall thickness in the circumferential direction of a product by an automatic regulation mechanism. CONSTITUTION:The title extruding equipment is equipped with a wall thickness measuring sensor 27 for measuring the distribution of wall thickness in the circumferential direction of an extruded synthetic resin pipe, an arithmetic output device 28 which computes and outputs the correction amount of a mold correspondent to deviation in the circumferential direction of inputted wall thickness, a mold regulation mechanism 29 which moves the tip part of the mold 1 in the radial direction for a core metal in accordance with the inputted correction amount of the mold and a displacement sensor 15 for detecting the moving direction and the moving amount in the radial direction of the tip part of the mold 1. The detected amount of the displacement sensor 15 is fed back to this arithmetic output device 28. The arithmetic output device 28 recomputes the correction amount of the mold from both the computed and output correction value of the mold and moving amount information of the tip part of the mold which is inputted from the displacement sensor 15. The recomputed correction amount of the mold is output to the mold regulation mechanism 29. The tip part of the mold 1 is corrected and moved in the radial direction for the core metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin pipe extrusion molding apparatus having a mechanism for correcting the deviation in wall thickness in the circumferential direction.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional synthetic resin pipe extrusion molding apparatus. A solid thermoplastic synthetic resin molding material is supplied from a hopper 21 into a cylinder (barrel) 22 that is heated by a heater, and the resin in the cylinder 22 is kneaded, heated, and plasticized by the rotation of the screw in the cylinder 22, and the mold at the tip of the cylinder It is extruded from the (die) 23, cooled in a water tank 24, and cut into a predetermined length by a drawing cutter 25 by a drawing machine 25.

A core metal (core) is fixed to the central axis of the opening of the mold 23, a cylindrical molten resin flow path is formed between the mold and the core, and a pipe is continuously extruded. It can be molded.

The wall thickness of the pipe is determined by the amount of molten resin passing through the resin flow path at the tip of the mold and the speed of drawing. The thickness deviation in the circumferential direction means that when there is a temperature deviation in the circumferential direction of the resin flow path at the tip of the mold, that is, the high temperature portion has a large amount of molten resin passing through and the wall thickness is large. Become. And, even if the cross-sectional shape of the resin flow path at the tip of the die is uneven in the circumferential direction, the deviation in wall thickness naturally occurs.

As a measure against the deviation of the wall thickness in the circumferential direction due to the former cause, for example, in Japanese Patent Publication No. 2-8569, a plurality of heating means are dividedly arranged on the outer peripheral portion of the die to measure the wall thickness. Correspondingly, a technique for controlling the heating effect of the particular heating means is disclosed.

As a measure against the latter, the die or the cored bar is moved so that the gap can be changed, and the gap is adjusted by the measured value of the wall thickness of the product.

[0007] Conventionally, as a technique applicable to this kind of wall thickness adjusting mechanism, there is, for example, "a pipe bending portion forming mechanism in a bent pipe manufacturing apparatus" disclosed in Japanese Utility Model Publication No. 2-44983.

FIG. 5 is a cross-sectional view of a die part for explaining the main part of the same technique, and the prior art will be described with reference to the same figure. A metal core (core) 2 is provided in the tip of a metal mold (die) 1, and the metal mold 1 or the metal core 2 can be moved vertically and horizontally by a driving mechanism. This is a mechanism for manufacturing a bent pipe by changing the width of the inner flow path 5 in the circumferential direction, that is, by changing the supply amount of the raw material resin in the circumferential direction.

If a straight pipe is drawn out by applying this mechanism, the wall thickness of the portion where the amount of the raw material resin is supplied becomes thicker and the portion where the supply amount of the raw material resin is smaller becomes thinner. Therefore, the deviation of the wall thickness of the product in the circumferential direction is measured,
By moving the mold 1 or the cored bar 2 vertically and horizontally, the wall thickness of the tube can be adjusted uniformly in the circumferential direction.

FIG. 6 is a schematic front view of a mold part showing another conventional thickness adjusting mechanism, and FIG. 7 is a sectional view of the mold part.

The cored bar 2 is fixed to the molding apparatus main body 8 and is located inside the mold 1. The mold 1 is divided into a mold body 1a and a mold tip 1b, and the mold tip 1b is provided with a plurality of uneven thickness adjusting bolts 27 with respect to the mold body 1a fixed to the molding apparatus body 8. By adjusting the position in the radial direction and fixing it to the mold body 1a, the deviation in the circumferential direction of the gap 5 between the mold tip 1b and the core metal 2 can be corrected.

[0012]

However, in the above-mentioned prior art, for example, in the structure in which a plurality of heating means are arranged in a divided manner, there is a time delay from the start of the temperature adjustment until the effect of correcting the deviation of the wall thickness comes out. However, there are limits to the functions and effects of stable thickness deviation adjustment. Further, the temperature unevenness of the molten resin may cause uneven surface gloss of the product.

Further, in the method in which the die tip portion 1b is movable in the radial direction with respect to the core metal 2 and the deviation in the circumferential direction of the cross-sectional shape of the resin flow path is corrected, the thickness of the product is reduced. It requires a lot of work such as measuring and finding a deviation, manually adjusting the mold, checking the result, and re-correcting if necessary, and also constantly measuring the wall thickness to monitor the product, Making necessary corrections and adjustments will reduce production efficiency.

The amount of movement required for the die tip 1b is calculated, and the correction mechanism such as the uneven thickness adjusting bolt 27 is manually operated in order to move the die tip 1b by the required amount. Alternatively, even if the correction mechanism is operated by mechanical means, gaps / plays, backlash, member distortion, deviation, etc. are unavoidable in the input means, the inside of the correction mechanism, etc., and molten resin with high temperature and pressure is introduced It is difficult to always move and fix the die tip 1b to be molded by an extremely slight correction amount, and it is confirmed from the product thickness check whether the die tip 1b is fixed at an appropriate position. However, there is a problem in that the quality of the product cannot be maintained unless it is re-corrected if necessary, and that it takes a considerable amount of time before the re-correction, and defective products continue to be manufactured during that time.

The present invention has been made in order to solve the above-mentioned problems of the prior art.
It is an object of the present invention to provide a synthetic resin pipe extrusion molding apparatus capable of always producing a synthetic resin pipe having a uniform thickness in the circumferential direction of a product.

[0016]

Therefore, a synthetic resin pipe extrusion molding apparatus according to the present invention comprises a wall thickness measuring sensor for measuring a circumferential wall thickness distribution of a synthetic resin pipe extruded,
A calculation output device that inputs measurement information from the wall thickness measurement sensor and calculates and outputs a mold correction value corresponding to the circumferential deviation of the wall thickness, and a mold according to the mold correction value input from the calculation output device. A displacement adjusting sensor for detecting the direction and the amount of movement of the tip of the die in the radial direction with respect to the core, and a displacement sensor for detecting the direction and amount of the movement of the tip of the die in the radial direction with respect to the core. The detected output value is fed back to the calculation output device, and the calculation output device again calculates the mold correction value from the calculated and output mold correction value and the movement amount information of the mold tip portion input from the displacement sensor, and It is an object of the present invention to achieve the above-mentioned object by a configuration characterized in that the tip end portion of the mold is corrected and moved in the radial direction with respect to the core metal by outputting to the mold adjusting mechanism.

[0017]

With the above construction, the wall thickness measuring sensor measures the wall thickness distribution in the circumferential direction of the extruded synthetic resin pipe, and the arithmetic output device inputs the measurement information from the wall thickness measuring sensor to measure the wall thickness in the circumferential direction. The mold correction value corresponding to the bias is calculated and output. Then, the mold adjusting mechanism moves the tip portion of the mold in the radial direction with respect to the core metal according to the inputted mold correction value.

Then, the displacement sensor detects the direction and amount in which the tip of the mold moves in the radial direction with respect to the core metal, feeds back the detected value to the arithmetic output device, and the arithmetic output device outputs the arithmetic operation. The mold correction value is calculated again from the mold correction value and the movement amount information of the tip part of the mold input from the displacement sensor, and it is output to the mold adjustment mechanism to move the tip part of the mold in the radial direction with respect to the core metal. By moving it to
It is possible to always extrude and mold a synthetic resin pipe having a uniform thickness in the circumferential direction of the product.

The error of the moving amount with respect to the mold correction value is immediately calculated from the moving amount information fed back to the calculation output device, and the mold tip value is corrected and moved in the radial direction by outputting the mold correction value again. Therefore, unlike the conventional apparatus, there is almost no time delay for correction, and a synthetic resin pipe having a uniform wall thickness can always be extruded.

[0020]

EXAMPLES A synthetic resin pipe extrusion molding apparatus according to the present invention will be described below with reference to Examples.

FIG. 1 is a block diagram of a synthetic resin pipe extrusion molding apparatus of one embodiment, and the same or corresponding parts as those of the conventional example shown in FIG.

A cylinder (barrel) 22 in which a solid thermoplastic synthetic resin molding material is heated by a heater from a hopper 21.
The resin is kneaded, heated and plasticized by the rotation of the screw in the cylinder 22, and extruded from the die (die) 1 at the tip of the barrel. A core is fixed to the center of the opening of the mold 1, a cylindrical molten resin flow path is formed between the mold and the core, and a pipe is continuously extruded. It can be molded. Then, it is cooled in the water tank 24 to form a shaped tube and its shape and dimension are stabilized.
Then, the drawer cutter 26 is used to cut into a predetermined length.

In the present embodiment, between the water tank 24 and the take-up machine 25, the ultrasonic-utilized meat for measuring the wall thickness every 1 degree of the circumferential angle while rotating the outer circumference of the molded pipe cooled in the water tank 24. A thickness measuring sensor 27 is installed, and the wall thickness measuring sensor 27 outputs the measured circumferential wall thickness distribution information of the molded pipe to the calculation output device 28. The calculation output device 28 is the wall thickness measurement sensor 2
The measurement information from 7 is input, a mold correction value for correcting the state of the mold corresponding to the deviation of the wall thickness in the circumferential direction is calculated, and is output to the mold adjusting mechanism 29 described later. Then, the die adjusting mechanism 29 moves the tip end portion of the die 1 in the radial direction with respect to the core metal in accordance with the die correction value input from the calculation output device 28, and the radial width of the die portion flow path of the molten resin. It is configured to adjust the circumferential bias of the.

A displacement sensor 15 is attached to the die 1 to detect the direction and the amount of movement of the tip of the die 1 in the radial direction with respect to the core metal by the operation of the die adjusting mechanism 29. The detection value of the sensor 15 is fed back to the calculation output device 28, and the calculation output device 28 again calculates the mold correction value from the mold correction value output previously and the movement amount information input from the displacement sensor 15, and the mold adjusting mechanism. The data is output to 29 and the die 1 is corrected again.

FIG. 2 is a schematic front view of the mold part showing the construction of the mold adjusting mechanism 29 of the above embodiment, and FIG. 3 is a schematic cross-sectional view of the mold part.

In both figures, the core metal 2 is fixed to the main body 8 of the molding apparatus and is located inside the mold 1. The mold 1 is divided into a mold main body 1a and a mold front end 1b, and the mold front end 1b is configured to be movable vertically and horizontally with respect to the mold main body 1a fixed to the molding apparatus main body 8. Has been done.

Reference numeral 3 denotes a first eccentric ring, which has an annular shape having an eccentric outer circumference and an inner circumference, and is slidably held in a circular concave portion of the end surface of the mold body 1a. Reference numeral 4 denotes a second eccentric wheel, which has an annular shape in which the outer circumference and the inner circumference are eccentric, and is slidably held in the first eccentric wheel 3. The die tip portion 1b is held by the second eccentric wheel 4.

That is, the first eccentric wheel 3 and the second eccentric wheel 4
Is rotated to move the tip 1b of the mold 1 to the core 2
On the other hand, the eccentric wheel for adjusting the wall thickness is formed which can be moved in the vertical and horizontal directions to correct the circumferential deviation of the gap width 5 between the core metal 2 and the mold 1.

The first eccentric wheel 3 and the second eccentric wheel 4 are respectively provided with driving end portions 6 and 7 for turning from the outside, and a driving power portion 9 attached to a pedestal portion of the molding apparatus main body 8. 10 and connecting rods 11 and 12 are connected.

The drive power units 9 and 10 are servo motors 13,
14 and rotates by a predetermined number of revolutions by the drive power controlled according to the mold modification value input from the arithmetic output device 28, and converts this revolution into vertical movement to connect rod 11,
12, the eccentric wheels 3 and 4 for adjusting the wall thickness are rotated by a predetermined angle, and the tip portion 1b of the mold 1 is moved in the radial direction with respect to the cored bar 2 so that the mold portion flow path 5 of the molten resin is formed. Is configured to adjust the circumferential deviation of the radial width of the mold. The mold adjusting mechanism 29 is formed by the wall thickness adjusting eccentric wheels 3 and 4, the driving power units 9 and 10, and the connecting rods 11 and 12. There is.

Reference numeral 15 denotes the above-mentioned displacement sensor, which is provided with the mold body 1a so that the mold adjusting mechanism 29 can detect the direction and the amount of movement of the tip portion 1b of the mold 1 with respect to the core metal 2 in the radial direction. Two pieces are arranged at an interval of about 90 degrees between the mold tip 1b.

With the above configuration, the circumferential wall thickness distribution of the composite pipe measured by the wall thickness measuring sensor 27 is input to the calculation output device 28, and the state of the mold is dealt with in accordance with the circumferential deviation of the wall thickness. A die correction value for correcting the value is calculated and output, and the tip end portion 1b of the die is output by the die adjusting mechanism 29 according to the die correction value.
Can be moved in the radial direction with respect to the core metal 2 to adjust the circumferential deviation of the radial width of the mold part flow path 5 of the molten resin.

The calculation output device 28 then outputs the mold correction value previously output from the circumferential wall thickness distribution information of the synthetic pipe from the wall thickness measuring sensor 27 and the tip portion of the mold fed back from the displacement sensor 15. The die correction value is calculated again based on the movement amount information of 1b and is output to the die adjusting mechanism 29 to correct and move the tip portion 1b of the die in the radial direction with respect to the core metal 2, so that the product circle is always circled. It is possible to extrude and mold a synthetic resin pipe having a uniform thickness in the circumferential direction.

The error of the moving amount with respect to the outputted mold correction value is immediately calculated from the moving amount information fed back to the calculation output device 28, and the mold tip portion 1b is radiused by outputting the mold correction value again. Since the correction is moved in the direction, unlike the conventional apparatus, there is almost no time delay required for the correction, and a synthetic resin pipe having a uniform wall thickness can always be extruded.

[0035]

As described above, according to the present invention, the wall thickness measuring sensor measures the wall thickness distribution in the circumferential direction of the extruded synthetic resin pipe, and the arithmetic output device uses the wall thickness measuring sensor to measure the measurement information. Is input and the mold correction value corresponding to the deviation in wall thickness in the circumferential direction is calculated and output. Then, the mold adjusting mechanism moves the tip portion of the mold in the radial direction with respect to the core metal according to the mold correction value, and corrects the circumferential deviation of the radial width of the mold resin passage of the molten resin. It is possible to extrude and mold a synthetic resin pipe having a uniform thickness in the circumferential direction of the product.

Then, the die correction value is calculated again from the die correction value output from the wall thickness distribution information and the movement amount information of the tip portion of the die, and the tip portion of the die is moved in the radial direction with respect to the core metal. By correcting and moving the product, it is possible to always extrude a synthetic resin pipe having a uniform thickness in the circumferential direction of the product.

That is, the deviation of the wall thickness is automatically monitored, and the operation error due to the state of the apparatus is also corrected and adjusted, so that the synthetic resin pipe having no deviation in the wall thickness in the circumferential direction of the product can be always manufactured.
Products with stable quality and appearance can be manufactured. In addition, the man-hours required for monitoring and adjustment can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a schematic front view of the mold adjusting mechanism of the embodiment.

FIG. 3 is a schematic cross-sectional view of a mold adjusting mechanism of the embodiment.

FIG. 4 is a configuration diagram of a conventional synthetic resin pipe extrusion molding apparatus.

FIG. 5 is a cross-sectional view of a mold portion of a conventional example.

FIG. 6 is a schematic front view of a mold part showing a wall thickness adjusting mechanism of a conventional example.

FIG. 7 is a schematic cross-sectional view of a die part showing a conventional wall thickness adjusting mechanism.

[Explanation of symbols]

 1 Mold 1a Mold Main Body 1b Mold Tip 2 Core Metal 3 First Eccentric Ring (Mold Adjusting Mechanism) 4 Second Eccentric Ring (Mold Adjusting Mechanism) 5 Flow Path (Gap) 6,7 Drive End 9, 10 Driving power unit (mold adjusting mechanism) 11, 12 Connecting rod (mold adjusting mechanism) 13, 14 Servo motor 15 Displacement sensor 27 Wall thickness measuring sensor 28 Calculation output device 29 Mold adjusting mechanism

Claims (1)

[Claims] 1. A wall thickness measuring sensor for measuring the wall thickness distribution in the circumferential direction of an extruded synthetic resin pipe, and a mold corresponding to the deviation of the wall thickness in the circumferential direction by inputting measurement information from the wall thickness measuring sensor. A calculation output device for calculating and outputting a correction value, a mold adjusting mechanism for moving the tip portion of the mold in the radial direction with respect to the core metal according to the mold correction value input from the calculation output device, A displacement sensor that detects the direction and amount of movement of the tip portion in the radial direction with respect to the core metal is fed back, and the detection value of the displacement sensor is fed back to the calculation output device, and the calculation output device corrects the mold by the calculation output. The die correction value is calculated again from the value and the movement amount information of the die tip portion input from the displacement sensor and output to the die adjusting mechanism to correct the die tip portion in the radial direction with respect to the core metal. Extruded synthetic resin pipe characterized by moving Shape device.