JPH0373327A - Extruder - Google Patents

Abstract

PURPOSE:To instantaneously change the volume of a head inner chamber so as to control the pressure in the head inner chamber in order to make the accurate control of extrusion rate possible by a method wherein a movable head part is shifted by means of a movable head part driving mechanism on the basis of at least either one of sensed quantities of the pressure in the head inner chamber and of the shape of an extruded product. CONSTITUTION:An extruder head 4 consists of a fixed head part 5 and a movable head part 6 so as to extrude molten resin material in a heating cylinder 1 by means of a screw 3 through a die 11 in order to produce a product. In this case, when the pressure in a head inner chamber 9 changes, the pressure change is detected with a pressure measuring device. Further, when scattering develops in the sectional dimensions and the like of a product, the scattering is detected with a shape measuring device 17. The selected result signals are inputted in a controller 16. The controller 16 actuates oil hydraulic cylinders 22 on the basis of said signals so as to change the volume of the head inner chamber 9 by shifting the movable head part 6 in order to instantaneously control the pressure in the head inner chamber, resulting in enabling to extrude a homogeneous product. Further, only either one of the pressure measuring device 14 and the shape measuring device 17 may be also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an extruder used for extrusion molding of resin products and the like.

Conventional technology This type of extruder has traditionally taken various measures to prevent variations in the cross-sectional dimensions and weight of the product extruded from the die due to variations in the properties and behavior of materials such as resin. I have been teaching.

For example, the extruder disclosed in Japanese Patent Publication No. 6154654 detects the pressure of the molten material in the extrusion head with a pressure sensor, adjusts the rotational speed of the extrusion screw based on this detection result, and extrudes the material from the die. The amount of extrusion is controlled to prevent variations in the cross-sectional dimensions of the products.

Problems to be Solved by the Invention However, in this type of conventional technology, the amount of extrusion is controlled by adjusting the rotational speed of a screw that spirally delivers the molten material, so it is difficult to adjust the amount of extrusion per unit time. The amount was small, and it took time to complete increasing or decreasing the extrusion amount after the pressure sensor signal was input, and it was not possible to sufficiently absorb variations in the cross-sectional dimensions of the product extruded from the goo. .

Means for Solving the Problems The extruder of the present invention has been made in view of the problems of the prior art described above, and has an extrusion head composed of a fixed head section and a movable head section, and has a pressure control system for detecting the internal pressure of the head. It is equipped with at least one of a measuring device and a shape measuring device that measures the shape of the product extruded from the goo, and the movable head section is moved based on the detection amount of at least one of the pressure measuring device and the shape measuring device, and the internal volume of the head is measured. It is characterized by being equipped with a movable head drive mechanism that changes the

A movable head drive mechanism moves the movable head based on measurements of at least one of the internal pressure of the working head and the shape of the product extruded from the goo. As a result, the head internal volume changes, and the head internal pressure is quickly adjusted to accurately control the extrusion amount.

Example Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a sectional view of essential parts of an extruder showing a first embodiment of the present invention. In this figure, l is a heating cylinder, and an internal chamber 2 of this heating cylinder 1 accommodates a scraper L3. Further, an extrusion head 4 is attached to the tip of the heating cylinder 1. The extrusion head 4 is composed of a fixed head section 5 fixed to the heating section I and a movable head section 6 slidably assembled to the fixed head section 5. Then, the fixed head section 5
A head inner chamber 9 is formed by the hollow holes 7 and 8 of the movable head portion 6. This head inner chamber 9 communicates with the inner chamber 2 of the heating cylinder I, and its volume decreases or increases as the cylindrical portion 10 of the movable head section 6 moves in and out of the hollow hole 7 of the fixed head section 5. It is supposed to be done. 11 is Gui,
This gouer 11 is arranged at the end of the hollow hole 8 of the movable head section 6.

This die 11 has an extrusion hole 12 of a desired shape approximately in the center thereof.
The movable head portion 6 is fastened to the movable head portion 6 by a pusher 13. 14 is a pressure measuring device attached to the movable head section 6. The pressure measuring device 14 measures the pressure inside the head via a pressure detection hole 15 opened in the hollow hole 8 of the movable head section 6, and outputs the measurement result to the controller 16. 17 is a shape measuring device placed outside the pusher 13. This shape measuring device 17 is arranged so as to be movable together with the movable head section 6.
The cross-sectional dimensions of the product extruded from the die 11 are measured, and the measurement results are output to the controller 16.

Reference numeral 18 denotes a movable head drive mechanism, and the movable head drive mechanism 8 drives the movable head 6 based on an output signal from at least one of the pressure measuring device 14 and the shape measuring device 17. This movable head drive mechanism 18 is a pressure measuring device 1.
The controller 16 outputs control signals based on input signals from the controller 16, and the hydraulic unit I9 is operated by the control signals from the controller 16. The hydraulic unit 19 includes a hydraulic pump 20. hydraulic valve 21,
It is composed of a hydraulic cylinder 22 and a hydraulic pipe 23 connecting these cylinders, and the operation of the hydraulic valve 21 is controlled by a controller 16. and,
The hydraulic cylinder 22 is fixed to the fifth fixed head,
To reciprocate the piston rod 24? This moves the movable head fffi6.

According to the above embodiment structure, heating g? The material such as resin softened and melted in the Jl is continuously passed through the die 11 with the screw 3.
A product of a desired shape is formed by extrusion from a material. At this time, if there are variations in the properties and behavior of the materials, the pressure in the head interior chamber 9 will fluctuate. This pressure fluctuation is detected by the pressure measuring device 14, and the detection signal is sent to the controller 1.
6 is input. Furthermore, when the pressure in the head interior chamber 9 fluctuates, variations occur in the cross-sectional dimensions of the product extruded from the die 1■, but the dispersion in the cross-sectional dimensions of the product is measured by the shape measuring device 17, and the measurement results are is controller 16
is man-powered. The controller 16 controls the hydraulic valve 21 based on signals from the pressure measuring device 14 and the shape measuring device 17.
A control signal is output to the hydraulic cylinder 22 to operate the hydraulic cylinder 22.

As a result, the movable head 6 moves, the volume of the head interior chamber 9 changes, and the pressure of the head interior chamber 9 is adjusted. Since the following two series of operations are performed instantaneously, there is no variation in product shape, and a homogeneous product can be extruded.

In this embodiment, the pressure measuring device 14 and the shape measuring device 17 are provided, but only one of them may be provided.

FIG. 2 is a sectional view of a main part of an extruder showing a second embodiment of the present invention. Hereinafter, in this second embodiment, explanations of the structures that are similar to those of the first embodiment will be omitted, and only the structures that are different from the first embodiment will be explained.

That is, in the unimplemented example, the cylindrical portion IO of the sixth movable head is slidably fitted onto the fifth fixed head, and the sixth movable head is slidably fitted onto the fifth fixed head.
The hydraulic cylinder 22 is fixed to the structure. This embodiment also provides the same effects as the first embodiment.

FIG. 3 is a sectional view of a main part of an extruder showing a third embodiment of the present invention.

In this embodiment, the extrusion head 4 is attached approximately at right angles to the heating cylinder l. This extrusion head 4 consists of a fifth fixed head fixed to the heating cylinder l and a sixth movable head slidably engaged with the fifth fixed head. The hydraulic cylinder 22 attached to the fifth fixed head moves the sixth movable head via the frame 25.

This embodiment also provides the same effects as the first embodiment.

FIG. 4 is a sectional view of a main part of an extruder showing a fourth embodiment of the present invention.

In this embodiment, a hydraulic cylinder 22 is attached to a fifth fixed head fixed to a heating cylinder I, and a sixth movable head is attached to the tip of a piston rod 24 of this hydraulic cylinder 22. Then, the sixth movable head is moved by the hydraulic cylinder 22.
is moved in and out of the fifth hollow hole 7 of the fixed head to change the volume of the head interior chamber 9. The head interior chamber 9 is composed of the hollow hole 7 of the fixed head section 5 and the movable head section housing hole 26 that opens into the hollow hole 7. This embodiment also provides the same effects as those of the embodiments described above. Although this embodiment uses a hydraulic unit as the drive mechanism, other drive mechanisms using an electric motor or the like may be used.

FIG. 5 is a sectional view of a main part of an extruder showing an application example of the first embodiment. In this embodiment, the hydraulic cylinder 22 is connected to the extrusion head 4.
This embodiment differs from the first embodiment in that the second embodiment is built into the first embodiment.

That is, as shown in FIG. 5, the hydraulic cylinder 22 has an oil chamber 30 formed between the fixed head section 5 and the movable head section 6.
And, there are two oil chambers 30a.

The flange 31 of the movable head section 6 defined in 30b, the hydraulic gaskets 32, 33, 34.35 that seal between the fixed head section 5 and the movable head section 6, and these hydraulic gaskets 32.33, 34.35. A packing fixing ring 36.3 that fixes each to the fixed head part 5 or the movable head part 6.
7.38, 39°40. and,
The oil chamber 30 is connected to the hydraulic unit 19. 4I is O
It's a ring.

Incidentally, according to this embodiment, the cylindrical portion IO of the movable head portion 6
The seven flange 31 formed in the hydraulic cylinder 22 functions as a piston and a piston rod.

This embodiment also provides the same effects as the first embodiment, and by incorporating the hydraulic cylinder 22 into the extrusion head 4, the extruder can be made more compact.

Effects of the Invention As described above, the present invention comprises an extrusion head consisting of a fixed head part and a movable head part, a pressure measuring device for detecting the pressure inside the head, and a shape measuring device for measuring the shape of the product extruded from the goo. Since the movable head drive mechanism moves the movable head based on the detected amount of at least one of the pressure measuring device and the shape measuring device, the internal volume of the head changes instantaneously. Inner chamber pressure can be adjusted. Therefore, the extrusion amount can be controlled accurately,
Enables extrusion molding of homogeneous products with little variation in shape.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main parts of an extruder showing a first embodiment of the present invention, and FIGS. 2 to 4 are sectional views of main parts of an extruder showing second to fourth embodiments of the invention. , FIG. 5 is a sectional view of a main part of an extruder showing an application example of the first embodiment. 4... Extrusion head, 5... Fixed head section, 6...
Movable head section, 9... Head inner chamber, 11... Gui,
I4... Pressure measuring device, 17... Shape measuring device, 18.
...Movable head drive mechanism.

Claims (1)

[Claims] (1) The extrusion head is composed of a fixed head part and a movable head part, and is equipped with at least one of a pressure measuring device for detecting the internal pressure of the head and a shape measuring device for measuring the shape of the product extruded from the die. An extruder comprising a movable head drive mechanism that moves the movable head based on the amount detected by at least one of a measuring device and a shape measuring device, and changes the internal volume of the head.