JPH10202724A - Automatic wall thickness adjusting device in extrusion molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust wall thickness by accurately measuring the wall thickness distribution in the circumferential direction of a molded pipe. SOLUTION: An operation processing apparatus 25 corrects the measured value of a wall thickness measuring sensor 24 for measuring the wall thickness distribution of an extrusion molded pipe 10 on the basis of the output from a temp. sensor 23 measuring the temp. of the molded pipe 10 to calculate accurate wall thickness distribution. An eccentric wheel driving means consisting of drive brackets fixed to eccentric wheels 13, 14, connected rods connected to the drive brackets, and drive power parts 19, 20 for driving the connection rods linearly and reciprocatingly receives the output from the operation processing apparatus 25 to make the width distribution of a resin passage variable to control wall thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic thickness adjusting device for an extrusion molding device, and more particularly to an automatic thickness adjusting device for automatically adjusting the thickness of a synthetic resin tube extruded in a vinyl chloride synthetic resin tube extrusion molding device. The present invention relates to a thickness adjusting device.

[0002]

2. Description of the Related Art Conventionally, in extrusion molding of a vinyl chloride synthetic resin tube, circumferential wall thickness distribution information of a molded tube measured by a wall thickness measuring sensor using ultrasonic waves is input to an arithmetic processing unit. A mold position correction value corresponding to the circumferential deviation of the wall thickness is calculated and output from the arithmetic processing unit, and the mold position is manually adjusted based on the calculated output.

In a conventional mold adjusting mechanism, a land of a mold is arranged outside a cored bar, and an eccentric ring is provided on the land.
By manually rotating the eccentric ring, the eccentric ring is set at a mold position corresponding to the circumferential deviation of the wall thickness.

[0004]

In a vinyl chloride synthetic resin, the propagation speed of an ultrasonic wave rapidly changes depending on the resin temperature. FIG. 4 is a diagram showing the relationship between the temperature of the vinyl chloride synthetic resin and the ultrasonic wave propagation velocity. As is apparent from FIG. 4, when the resin temperature becomes 80 ° C. or higher, the ultrasonic wave propagation speed changes rapidly.

When a molded synthetic resin tube is measured by an ultrasonic wall thickness measuring sensor, the measured value varies depending on the temperature. Enter the thickness conversion factor,
Each time the replacement inspector changes the extrusion conditions (extrusion amount and resin temperature), the die is adjusted by setting the coefficient. As described above, in the conventional thickness adjusting device, it is difficult to automatically control the die adjustment due to the variation in the measured thickness, and the operator has to manually adjust the die adjustment. It took time to cope with the fluctuation, the change of the extrusion amount, the change of the size, and the like, which was a factor of the generation of scrap. In addition, there is a problem that as the size of the tube increases, the error increases and the efficiency decreases. Furthermore, when the extrusion conditions are unstable, the error in the measured wall thickness is large, making it impossible to adjust the thickness deviation of the mold. However, there is a problem that the temperature decreases.

The present invention has been made in view of such a problem, and an object of the present invention is to accurately measure the thickness distribution of a molded pipe regardless of the resin temperature and to measure the measured thickness. An object of the present invention is to provide an automatic thickness adjusting device in an extrusion molding device that enables automatic thickness adjustment control by automatically controlling a mold based on a distribution and improves production efficiency by reducing the number of work steps.

[0007]

In order to achieve the above object,
The automatic thickness adjusting mechanism in the extrusion molding apparatus according to the present invention drives the eccentric wheel to move the mold in the radial direction with respect to the core metal, and the circumferential deviation of the radial width of the resin flow path of the molten resin. The thickness distribution of the extruded molded tube is measured using an ultrasonic wave in the automatic thickness adjustment device of the extrusion molding device, which adjusts the thickness of the extruded molding tube to correct the unevenness in the circumferential direction of the molded tube. Tube thickness measurement unit provided with a wall thickness measuring sensor to measure the temperature of the molded tube, a driving bracket fixed to an eccentric ring, a connecting rod connected to the driving bracket, and a connecting rod An eccentric wheel drive means comprising a drive power unit for linearly reciprocating the drive, and a control means for controlling the drive power unit based on the calculation output of the measured data from the molded pipe wall thickness measurement unit by an arithmetic processing unit. Characterized by having

The arithmetic processing unit calculates the thickness distribution of the formed pipe using the ultrasonic wave propagation velocity corrected based on the output of the temperature sensor. The wall thickness measurement sensor has a surface temperature of 8
It is preferable to install at a position within 0 ° C. Further, the connecting rod can be provided with a length adjusting means capable of adjusting the length from the driving power unit to the driving bracket.

In the automatic wall thickness adjusting device of the extrusion molding apparatus according to the present invention, the distribution of the wall thickness of the molded pipe and the temperature of the molded pipe measured by the thickness measuring sensor and the temperature sensor are calculated. The ultrasonic wave propagation velocity is estimated and corrected based on the temperature information output from the temperature sensor input to the processing unit, and the drive power unit of the eccentric wheel is controlled by the output of the processing unit to control the eccentricity of the eccentric wheel. The amount is determined, and the circumferential deviation of the radial width of the resin flow path of the molten resin is adjusted to correct unevenness in the circumferential thickness of the molded pipe.

[0010]

FIG. 1 shows an automatic thickness adjusting mechanism in an extrusion molding apparatus according to one embodiment of the present invention. The extruder shown has an extruder 1 having a screw, a mold 2, a cooling water tank 3, a molded pipe wall thickness measuring section 4, a take-up machine 5, a marking device 6, and a cutter 7 arranged in this order. I have.

The resin pellets are supplied to the hopper 8 of the extruder 1 and are pressed and melted by a screw rotated by a drive motor, supplied to the mold 2 and extruded to obtain the resin pellets. The obtained vinyl chloride-based synthetic resin pipe (hereinafter, referred to as a molded pipe) 10 is cooled in the water tank 3, taken up by the take-up machine 5, and is marked to a required length by the marking device 6, and then cut into a predetermined length by the cutter 7. Things
This operation is similar to that of a conventional extrusion molding apparatus.

As shown in FIGS. 2 and 3, a core 11 is provided in the mold 2, and a land 12 which rotates outside the core 11 is provided at the front of the mold 2. . A first eccentric ring 13 composed of an outer eccentric ring is provided integrally with the land 12. A second eccentric ring 14 composed of an inner eccentric ring is rotated on the outer periphery of the first eccentric ring 13 via a bearing 27. It is provided freely. Drive brackets 15 and 16 are respectively fixed to the first eccentric wheel 13 and the second eccentric wheel 14, and the connecting rod 1 is attached to each of the drive brackets 15 and 16.
The lower ends of the connecting rods 17, 18 are connected to driving power units 19, 20.

Male screws (not shown) are formed at the lower ends of the connecting rods 17, 18, and drive power units 19, 20 are provided.
Internally, the connecting rods 17 and 18 are moved up and down by being driven by the worm gear mechanism of the driving power units 19 and 20. The eccentric wheels 13 and 14 rotate via the drive brackets 15 and 16 due to the vertical reciprocation of the connecting rods 17 and 18, and the lands 12 move in the radial direction according to the amount of rotation, and the resin flow around the outer periphery of the cored bar 11. Thickness control is performed by varying the width of the path 9.

The connecting rods 17 and 18 are connected to the driving brackets 15 and 16 from the driving power units 19 and 20 by screws.
Is provided with a length adjusting means 21 which can adjust the length to reach. The connecting rods 17 and 1 are controlled by the length adjusting means 21.
By adjusting the length of 8, the initial value of the thickness of the formed tube 10 can be arbitrarily set.

The molded pipe thickness measuring section 4 is provided with a thickness measuring sensor 24 which rotates around the molded pipe 10 and measures the thickness of the molded pipe 10 by ultrasonic waves. Further, the thickness measurement sensor 24 is equipped with a temperature sensor 23 for measuring the surface temperature of the molded pipe 10. As shown in FIG. 4, when the resin temperature becomes 80 ° C. or higher, the ultrasonic wave propagation velocity in the resin changes rapidly. Therefore, the installation position of the thickness measurement sensor 24 is preferably set at a position where the resin temperature of the molding tube 10 is within 80 ° C. in order to reduce the influence of the thickness measurement error due to temperature. As for the position where the resin temperature of the molded tube 10 is within 80 ° C., specific positions are collected as data depending on the size and the extrusion amount of the molded tube 10, and based on the data, the thickness measuring sensor 24 and the temperature sensor are used. 23 are determined.

As described above, when the resin temperature of the molded tube 10 is 80
By installing the thickness measuring sensor 24 at a position within the temperature range of ° C., it is possible to suppress the influence of the rapid change of the ultrasonic wave propagation speed due to the resin temperature. However, if the measurement value of the thickness measurement sensor 24 is corrected using the relationship between the resin temperature and the ultrasonic wave propagation velocity shown in FIG. It is not limited to the position where the temperature is within 80 ° C.

The operation of the automatic thickness adjusting device in the extrusion molding apparatus of the present embodiment configured as described above will be described. The molded tube 10 continuously extruded and molded from the mold 2 of the extruder 1 is taken up by the take-up device 5, and is formed by the thickness measuring sensor 24 and the temperature sensor 23 in the molded tube thickness measuring section 4 during that time. The wall thickness distribution and surface temperature of the tube 10 are measured.

Based on the temperature information output from the temperature sensor 23 and the relationship between the resin temperature and the ultrasonic wave propagation velocity in the resin shown in FIG. 4, the arithmetic processing unit 25 calculates the ultrasonic wave propagation velocity at the resin temperature. The accurate wall thickness distribution of the formed pipe 10 is obtained using the obtained ultrasonic wave propagation velocity.
The arithmetic processing unit 25 inputs the thickness distribution of the molded pipe 10 to the control means 26 such as a personal computer and controls the take-off machine 5 to control the take-up speed of the molded pipe 10. Control means 26
Controls the driving power units 19 and 20 to connect the connecting rods 17 and
By controlling the amount of protrusion of 18, the amount of eccentricity of the eccentric rings 13 and 14 is determined, and the width of the resin flow path 9 is varied to correct the circumferential unevenness of the thickness of the molded pipe 10 in the circumferential direction.

As described above, by calculating the temperature information output from the temperature sensor 23 together with the thickness information from the thickness measurement sensor 24, the thickness measurement error caused by the temperature dependence of the ultrasonic wave propagation velocity is obtained. , And accurate wall thickness adjustment can be performed automatically. As mentioned above, although one Embodiment of this invention was described in full detail, this invention is not limited to the said Embodiment, It deviates from the spirit of this invention described in the claim in design. Various changes can be made without.

For example, the length adjusting means 21 of the connecting rods 17, 18 may change the pivotal connection position between the connecting rods 17, 18 and the driving brackets 15, 16 instead of adjusting the screw. Any mechanism such as a rack and pinion mechanism and a cylinder mechanism can be used for the power units 19 and 20. Further, the wall thickness measurement sensor 24 does not necessarily need to be installed at a position where the resin temperature of the molding tube 10 is within 80 ° C., and the thickness measurement sensor 24 uses the relationship of FIG. By correcting the ultrasonic wave propagation velocity, it is possible to accurately measure the thickness of the formed tube.

[0021]

As can be understood from the above description, the automatic thickness adjusting apparatus in the extrusion molding apparatus of the present invention drives the eccentric wheel based on the molded pipe thickness data measured by the molded pipe thickness measuring section. Since the mold is controlled by driving the power unit, the mold adjustment, which was manually performed by the operator, is performed automatically. The mold can automatically and quickly follow changes in size, reducing man-hours and scrap, improving production efficiency, and installing a temperature sensor in the wall thickness measuring section to control the surface temperature of the molded pipe. Is used to correct the thickness data, so that the variation in the measured thickness value due to the change in the propagation speed of the ultrasonic wave depending on the resin temperature is eliminated, and accurate mold adjustment can be performed.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of an automatic thickness adjusting device in an extrusion molding device according to the present invention.

FIG. 2 is a front view of a mold part.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a diagram showing a relationship between a resin temperature and an ultrasonic wave propagation velocity.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 extruder 2 mold 4 molded pipe thickness measuring section 9 resin flow path 10 molded pipe 11 core metal 12 mold land 13 first eccentric ring 14 second eccentric ring 15, 16 drive bracket 17, 18 connecting rod 19, 20 drive power section 21 length adjustment means 23 temperature sensor 24 wall thickness measurement sensor 25 arithmetic processing unit 26 control means (PC)

Claims (3)

[Claims] An eccentric wheel is driven to move a mold in a radial direction with respect to a metal core, and a circumferential deviation of a radial width of a resin flow path of a molten resin is adjusted to adjust a circumferential direction of a molding tube. In an automatic thickness adjustment device of an extrusion molding device adapted to correct the thickness non-uniformity of a thickness, a thickness measurement sensor for measuring the thickness distribution of an extruded molded tube using ultrasonic waves, A molded pipe wall thickness measuring unit having a temperature sensor for measuring temperature; a driving bracket fixed to the eccentric ring; a connecting rod connected to the driving bracket; and a driving power for linearly reciprocatingly driving the connecting rod. An eccentric wheel driving means comprising: a control section for calculating the measurement data from the molded pipe wall thickness measuring section by an arithmetic processing device, and controlling the driving power section based on the calculation output. Extrusion molding equipment characterized by Kicking automatic thickness adjusting device. 2. The extrusion molding according to claim 1, wherein the arithmetic processing unit calculates the wall thickness distribution of the molded pipe using an ultrasonic wave propagation velocity corrected based on an output of the temperature sensor. Automatic thickness adjustment device in the device. 3. The automatic thickness adjusting apparatus according to claim 1, wherein the thickness measuring sensor is installed at a position where the surface temperature of the forming tube is within 80 ° C. apparatus.