JPH08207123A - Production of extrusion molded product changing in cross-sectional shape - Google Patents

Abstract

PURPOSE: To produce an extrusion molded product changing in its cross-sectional shape in an extremely economical and efficient manner by using a simple die structure without generating an excessive resin. CONSTITUTION: An extruder 2 molding the main body part having a constant shape of a molded product and an extruder 22 molding the shape changed part 12 of the molded product are provided to a die 23 and one or a plurality of shape changing plates changing an opening shape are provided to the opening part of the outlet of the die so as to be freely moved reciprocally by a drive mechanism. The driving of the shape changing plates and the screw rotating drive of the extruder 22 molding the shape changed part are allowed to be connected with each other to change a resin emitting amt. corresponding to the change of the shape of the opening part of the die.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an extruded product whose cross-sectional shape continuously changes.

[0002]

9 to 13 of the accompanying drawings show an example of an extruded product in which the cross sectional shape is partially changed in a continuous extruded product having the same cross sectional shape, such as an automobile wind molding. Be done.

This automobile window molding 10
As can be understood from FIG. 9 which is a cross-sectional view in the length direction thereof and FIGS. 10 to 13 which are cross-sectional views in the width direction thereof, a part of the main body portion 11 made of an extruded product having a constant cross-sectional shape. The shape changing portion 12 whose cross-sectional shape continuously changes is integrally formed.

That is, FIG. 10 shows a portion of the wind molding 10 in which the shape-changing portion 12 is completely formed, and FIG. 11 shows the shape-changing portion 1A.
Wind molding 10B with a partial decrease in 2 in Fig. 1
2 shows a wind molding 10C in which the shape changing portion 12 is further reduced, and FIG. 13 shows a wind molding 10D in which the shape changing portion 12 is not formed. As shown in the drawing, the shape changing portion 12 gradually moves from the main body portion 11 to It is formed by changing the cross-sectional shape.

By the way, as an apparatus for obtaining such an extrusion-molded article, as described in, for example, Japanese Patent Laid-Open No. 3-128721, it substantially corresponds to the cross-sectional shape of the side moldings attached to the both side edges of the windshield. An extrusion opening is provided in the molding die, and on the front surface of the molding die, the same as the first shutter for changing the wall thickness of the decorative portion of the molding, for changing the length of the decorative lip of the decorative portion. Disclosed is a molding device for a molding for a windshield of an automobile, in which a second shutter is mounted so as to be linearly movable.

According to this apparatus, each shutter is moved at right angles to the extrusion direction of the extruded product to continuously change the shape of the die opening, thereby partially changing the cross-sectional shape of the extruded product. You can

However, in the extrusion molding as described above, the extrusion discharge amount of the resin is determined when the cross-sectional area of the die opening is the largest, but when the area of the die opening is small, The resin pressure fluctuates due to the change in the area, and it becomes impossible to keep the extrusion conditions constant. Therefore, in order to maintain the balance between the resin pressure and the flow rate when the shape of the die opening changes, a bypass passage for excess resin is provided in the die, and the resin pressure etc. is adjusted by this bypass passage. Is proposed,
This method tends to make the die structure complicated.

Further, the resin discharged from the bypass flow path is discarded or sent to the regeneration step for reuse, but this method has a large loss in time and cost and is not always economical. Absent.

[0009]

SUMMARY OF THE INVENTION Therefore, the present invention
It has been proposed in view of the above problems, a simple die structure without adopting a complicated die structure such as a bypass channel, and an extremely economical and efficient cross-sectional shape with no excess resin generated. It is an object of the present invention to provide a method for producing an extruded product having a variable value.

[0010]

That is, the present invention provides:
When a long extrusion molded product whose cross-sectional shape continuously changes while discharging the resin from the die outlet by the screw rotation of the extruder is used, an extrusion for molding the main body of the molded product having a constant shape into the die. A machine and an extruder for molding a shape changing portion whose shape changes are provided, and one or a plurality of shape changing plates for changing the opening shape are reciprocally provided by a drive mechanism at the opening of the die outlet, and Driving the shape change plate and screw rotation drive of the extruder for forming the shape change portion are linked to each other, and the resin discharge amount of the extruder for forming the shape change portion corresponding to the change in the die opening opening shape is set. The present invention relates to a method for manufacturing an extruded product having a changed cross-sectional shape, which is characterized by being changed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. 1 is a schematic front view showing an example of an extrusion molding apparatus for carrying out the method of the present invention, FIG. 2 is a schematic front view showing an arrangement of a die opening and a shape change plate, and FIG. 3 is a view showing an example of a control system thereof. FIG. 4 is a chart showing an example of a coordinated operation of driving the shape changing plate and screw rotation driving of the extruder, FIG. 5 is a front view of a die opening showing an operating state of the shape changing plate, and FIG.
Is a cross-sectional view of the wind molding obtained by the die of FIG. 5, FIG. 7 is a cross-sectional view showing a state in which its shape is changed, and FIG. 8 is a cross-sectional view in which the shape is further changed.

FIG. 1 shows an example of an extrusion molding apparatus 20 for carrying out the method of the present invention. As shown in FIGS. 10 to 13, the wind molding product whose cross-sectional shape continuously changes is obtained. It is for. In the figure, reference numeral 21 is an extrusion molding machine that forms the main body portion 11 having a constant shape in the wind molding 10, and 22 is an extrusion molding machine that forms the shape changing portion 12 of the wind molding 10 that changes in shape. Reference numeral 23 is a die to which an extrusion molding machine 21 for forming the main body 11 having a constant shape and an extrusion molding machine 22 for forming the shape changing portion 12 are coupled, and 24 represents the die outlet.

In this embodiment, the extruder 21
Resins 22 and 22 discharge the resin from the die outlet by the rotation of the screw, and the rotation of the screw is driven by servomotors 25 and 26.

The resin outlet 24 of the die 23 is provided with a shape changing plate 30 for changing the shape of the outlet, as shown in FIG. The shape changing plate 30 is composed of one or a plurality of shutter-like opening / closing plates that slide on the front surface of the outlet 24, and is provided so as to be movable back and forth with respect to the die outlet by a drive mechanism 40 provided outside the machine.

The shape changing plate 30 moves forward and backward as the resin material is pushed out, thereby changing the shape of the die outlet 24 and continuously changing the cross-sectional shape of the molding 10. In this embodiment, the shape change plate 30 is used as the die outlet 24.
Three locations (30a, 30b, 30c) are provided in the periphery, and they reciprocate independently depending on the product shape.

The drive mechanism 40 for the shape changing plate 30 is a known cylinder device 41 for moving the shape changing plate 30 back and forth.
And a servo valve 42 for operating the cylinder device 41. In this embodiment, there are three shape change plates 30a, 30
drive mechanisms 40a, 40b, 40c and servo valves 42a, 4 for independently operating b, 30c.
2b and 42c are provided.

By the way, the resin pressure in the apparatus, which varies when the die opening area is varied, does not necessarily vary in the same manner on the ascending side and the descending side due to the viscosity and fluidity of the resin extruded. Absent. Therefore, when such a resin pressure is adjusted by the screw rotation speed and kept constant, it is preferable to adjust the opening / closing speed and timing of the mold with respect to the rotation speed.

Therefore, in the present invention, FIG. 3 and FIG.
As described above, the servo valves 42a, 42b, 4 of each drive mechanism for operating the shape changing plates 30a, 30b, 30c
2c and the servomotors 25 and 26 that drive the screw rotation of the extruders 21 and 22 are programmable controllers P.
Are connected via In this programmable controller P, a screw rotation speed adjusted in advance corresponding to the opening / closing operation of the shape changing plates 30a, 30b, 30c forming the shape of the cross section of the molded product and the resin pressure fluctuated by the opening / closing operation is programmed. It has been set as a computerized system and its operation is controlled.

That is, the shape change plates 30a, 30
When the area of the die outlet 24 is changed by advancing or retreating the b, 30c with respect to the die outlet 24, the rotation of the servomotor 26 of the extruder 22 for forming the shape changing portion according to the operation amount of the shape changing plate. The drive is adjusted, and the drive conditions such as the screw rotation speed and the screw rotation time are changed. As a result, the amount of resin discharged from the die outlet can be maintained at a predetermined amount, the resin pressure and flow rate inside the die can be kept constant, and a product with a good shape can be obtained.

FIG. 4 is an operation control flow chart showing an example of control of this operation program set in the programmable controller P. As can be seen from the figure,
The screw rotation drive of the extruder 2 that forms the shape change portion is adjusted in response to the driving (forward and backward) of the shape change plates (1) and (2). The screw rotational drive of the extruder 1 for molding the main body is constant because the shape is constant.

Further, in the present invention, a displacement sensor 27 is provided in the vicinity of the outside of the die outlet 24, the shape changing portion 12 of the molded product 10 extruded from the die outlet 24 is read, and this signal is programmable. By transmitting it to the controller P, repeated continuous molding of the same pattern is performed. When the shape change portion 12 of the molded product 10 extruded from the die outlet 24 by the displacement sensor 27 is directly read, it is more accurate than the conventional one in which molding is performed by the distance or time (timer) signal of the molded product. It is possible to perform molding control of various shape changes.

FIG. 5 is a front view of the die opening showing the operating state of the shape changing plate. Reference numeral 50 denotes an extrusion molding device, 51
Is a die and 52 is a die exit. In this example, two shape changing plates 53 and 54 provided on the die 51 are provided so as to be able to move forward and backward outside the die outlet 52. Code 5
Reference numerals 5 and 56 are drive devices.

The moldings obtained by this device 50 are shown in FIGS. Reference numeral 60 is a molding, 61 is an umbrella-shaped main body portion, and 62 is a fin portion, and the shapes of the leg portion 61a and the fin portion 62 of the main body portion 61 are partially and continuously changed.

[0024]

As shown and described above, according to the method of manufacturing an extrusion-molded article of the present invention, the screw rotation of the extruder for molding the shape-changing portion causes the operation of the shape-changing plate provided at the die outlet. Since they are changed in cooperation with each other, the resin pressure in the apparatus can be kept constant even if the area of the die opening changes. Therefore, it is not necessary to provide a surplus resin extracting mechanism for adjusting the resin pressure in the molding device, and it is possible to perform extremely economical and efficient molding without a resin loss with a simple device structure.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an example of an extrusion molding apparatus for carrying out the method of the present invention.

FIG. 2 is a schematic front view showing an arrangement of a die opening and a shape changing plate.

FIG. 3 is a diagram showing an example of a control system thereof.

FIG. 4 is a chart showing an example of a coordinated operation of driving the shape changing plate and screw rotation driving of the extruder.

FIG. 5 is a front view of a die opening showing an operating state of the shape changing plate.

6 is a cross-sectional view of a wind molding obtained by the die of FIG.

FIG. 7 is a cross-sectional view showing the changed state of the shape.

FIG. 8 is a cross-sectional view in a state where the shape is further changed.

FIG. 9 is a longitudinal cross-sectional view of a general automobile wind molding with a part thereof omitted.

10 is a cross-sectional view taken along line 10-10 of FIG.

FIG. 11 is a sectional view taken along line 11-11 of FIG.

FIG. 12 is a sectional view taken along line 12-12 of FIG.

FIG. 13 is a sectional view taken along line 13-13.

[Explanation of symbols]

 10 Wind Molding 20 Extrusion Molding Device 21 Extruder 22 Extruder 23 Die 24 Die Exit 25 Servo Motor 26 Servo Motor 30 Shape Change Plate 40 Drive Device 42 Servo Valve

Claims (2)

[Claims] 1. When obtaining a long extrusion-molded article whose cross-sectional shape continuously changes while discharging resin from a die outlet by rotating a screw of an extruder, the die has a main body of a constant shape among the molded articles. An extruder for molding a part and an extruder for molding a shape-changing part that changes shape are provided, and one or a plurality of shape-changing plates for changing the opening shape can be reciprocally moved by a drive mechanism at the opening of the die exit. And an extruder for forming the shape change portion corresponding to the change in the opening shape of the die opening, by coordinating the drive of the shape change plate and the screw rotation drive of the extruder for forming the shape change portion. The method for manufacturing an extrusion-molded article having a changed cross-sectional shape, characterized in that the resin discharge amount of is changed. 2. The shape change portion of a molded product extruded from the die outlet is read by a displacement sensor provided near the outside of the die outlet, and the shape change plate is driven and the shape is changed based on the signal. A method for manufacturing an extrusion-molded article, the cross-sectional shape of which is changed by correspondingly changing the screw rotational drive of an extruder for molding the changed portion.