JP2002225115A - Extrusion molding machine and method for molding using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extrusion molding machine capable of molding a material having a good accuracy by reducing a shrinkage difference at respective sites and a method for molding using the extrusion molding machine. SOLUTION: The extrusion molding machine 14 comprises an extruder 19 for extruding a molten resin in a mold 20 to mold the resin in a molding shape, and a cooling mold 21 for cooling to cure the extruded molding 30 by closely contacting the molding 30 with a mold provided in a circumference by performing evacuation into vacuum. The mold 21 has first to fourth vacuum evacuation zones 24 to 27 provided in a flowing direction and a sectional direction perpendicularly crossing with the flowing direction by extruding the molding 30, resin thermometers 39 to 41 provided at this side of the first to fourth vacuum evacuation ones 24 to 27 of the flowing direction to measure temperatures of the sites of the sectional direction of the molding 30, and a vacuum pressure controller 29 for regulating a vacuum pressure in response to the temperature detected by the thermometers 39 to 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruder used for molding long objects such as rain gutters and pipes, and a molding method using the extruder.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No. 5-38745 shown in FIG.
There is known an extruder and a molding method using the extruder as described in Japanese Patent Application Laid-Open Publication No. H11-163,036.

In such a device, the resin material charged into the cylinder 1 is heated by the heating / cooling units 2 and kneaded by the screw 3 and moves inside the cylinder 1 toward the connecting portion 4. .

At this time, a cylinder temperature adjusting unit (not shown) adjusts the heating / cooling units 2 in accordance with the output of the temperature sensors 5. When the resin is extruded toward the mold 6, the resin temperature is detected by the temperature sensor 7. It is configured so that the temperature matches the target resin temperature.

[0005] After being molded into a cylindrical shape in the mold 6, it is taken up by a take-up machine 8. At this time, the mold temperature adjusting sections 9 adjust the temperature of the heating sections 10 so that the temperature detected by the temperature sensors 11 becomes a desired temperature.

[0006] The resin material molded into a cylindrical shape is gradually cooled and hardened by contact with air.

[0007] A cooling mold is provided between the mold 6 and the take-off machine 8 to cool the resin material derived from the mold 6 in a short time to improve the production efficiency. Is also known.

[0008]

However, in such a conventional technique, when the extruded product is a U-shape such as a rain gutter, the cooling rate of each part may be different.

For example, as shown in FIG. 5, in a resin molded product 12 having a substantially U-shaped cross section having a B portion 12b cooled faster than the A portion 12a, as shown in FIG. After the B portion 12b, which has reached (or the softening temperature) first, starts to cure, the A portion 12a starts to cure, thereby causing a difference in shrinkage.

[0010] For this reason, there is a possibility that a distortion or a defect in the outer shape may occur, for example, a distortion is generated due to a difference in shrinkage, and a warp is caused in the direction of the A portion 12a.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems in the prior art, and an extruder and an extruder capable of forming a highly accurate molded product by reducing a difference in shrinkage at each part. An object of the present invention is to provide a molding method using a molding machine.

[0012]

In order to achieve the above object, according to the first aspect of the present invention, an extruder for extruding a molten resin into a mold to form a molded product, and an extruder for extruding the molded product. And a cooling mold that cools and cures by bringing the mold into vacuum and bringing it into close contact with a mold provided therearound, wherein the molded product is extruded and moved to the cooling mold. Temperature measuring means for providing a plurality of zones for evacuation in the flow direction and a cross-section direction orthogonal to the flow direction, and measuring the temperature of each part in the cross-section direction of the molded product in front of each zone in the flow direction. And an extruder having a vacuum pressure controller for adjusting the vacuum pressure in accordance with the temperature detected by the temperature measuring means.

[0013] According to the first aspect of the present invention, the vacuum pressure control unit may be evacuated according to the temperature of each part in the sectional direction of the molded product measured by the temperature measuring means. Is adjusted.

By adjusting the pressure of the evacuation, the degree of close contact with a mold provided around the periphery can be varied, and the cooling efficiency can be controlled.

[0015] For this reason, according to the temperature of each part of the molded article measured by the temperature measuring means, the cooling amount is appropriately changed to reduce the difference in shrinkage, so that a molded article with good accuracy can be molded. .

According to the second aspect of the present invention, in the vacuum pressure control unit, the vacuum pressure on the downstream side of the portion where the cooling is delayed is increased, or the vacuum pressure on the downstream side of the portion where the cooling is advanced is provided. A molding method using an extruder according to claim 1, wherein the vacuum pressure is reduced or at least one or both of them are controlled.

According to the second aspect of the present invention, the vacuum pressure control unit increases the vacuum pressure on the downstream side of the part where the cooling is delayed, or the downstream part of the part where the cooling is advanced. The vacuum pressure on the side is reduced or at least one or both are controlled.

For this reason, by appropriately changing the cooling amount in accordance with the temperature of each part of the molded product measured by the temperature measuring means and reducing the difference in shrinkage, a molded product with good precision can be molded. .

[0019]

Embodiment 1 Next, Embodiment 1 of the present invention will be described with reference to the drawings.

FIGS. 1 to 3 show an extruder and a molding method using the extruder according to the first embodiment of the present invention. Parts that are the same or equivalent to those in the conventional example will be described with the same reference numerals.

First, the construction will be described. In the extruder 14 of the first embodiment, a hopper 17 provided with valves 15 and 16 capable of adjusting a supply amount of a resin material and a screw feeder 18 connected to the hopper 17 are provided. There is provided an extruder 19 which is connected to the extruder.

A die 20 is disposed downstream of the extruder 19 in the flow direction, which is the extrusion direction.

When the molten resin material is pushed from the extruder 19 into the mold body 20a of the mold 20, an elongated molded product 30 having an approximately U-shaped cross section with an open upper portion is formed. It is configured to be molded into a shape and extruded.

Between the extruder 19 of the extruder 14 and a take-off device 22 for picking up the extruded molded product 30, the molded product 30 is evacuated to form a mold body 21 provided around the extruder.
A cooling mold 21 that is cooled and hardened by being brought into close contact with a is provided.

In the first embodiment, cooling of the mold body 21a is performed by cooling water.

In the cooling mold 21, a molded product passage 21 as shown in FIG. 3 is formed along a flow direction in which the molded product 30 is extruded and moves (a direction indicated by a white arrow in FIGS. 1 and 2).
An opening b is formed in a substantially U-shape so that the molded product 30 can be inserted. This molded product passage 21b is
c, right passage 21d and left passage 21e.

A pre-evacuation zone 23 is provided at the most upstream side around the molded product passage 21b, and first to fourth evacuation zones are provided from the pre-evacuation zone 23 to the downstream side. Zones 24-27 are sequentially arranged.

Around the molded product passage 21b of the pre-evacuation zone 23, a plurality of groove-shaped vacuum slits 32 connected to a vacuum pump 28 via an electromagnetic valve 31 are provided.
Are provided on both sides of each of the lower passage 21c, the right passage 21d, and the left passage 21e so as to evacuate in a cross-sectional direction orthogonal to the flow direction.

Around the molded product passage 21b in the first evacuation zone 24, an electromagnetic valve 33 is connected to a vacuum pump 28.
As shown in FIG. 3, the plurality of vacuum slits 36 to 38 connected to each other through the lower passages 2 to 35 perform vacuum evacuation in a cross-sectional direction orthogonal to the flow direction.
1c, a right passage 21d, and a left passage 21e.

In front of the flow direction of the first evacuation zone 24, resin thermometers 39 to 41 as temperature measuring means for measuring the temperature of each part in the sectional direction of the molded product 30 are provided. Each of the lower passages 21c and the right passage 21
d and on both sides of the left passage 21e, respectively.
It is connected to a vacuum pressure controller 29.

The vacuum pressure control section 29 opens and closes the connected solenoid valves 33 to 35 in accordance with the temperatures detected by the resin thermometers 39 to 41, and opens and closes the vacuum slits 36 to 38. Are configured to be individually variable.

The second to fourth evacuation zones 25 to
Similarly to the first evacuation zone 24, a plurality of vacuum slits 36 to 38 connected around the molded product passage 21b to the vacuum pump 28 via solenoid valves 33 to 35 flow in the same manner as in the first evacuation zone 24. The lower passage 21c, the right passage 21d and the left passage 21e are provided on both sides of the lower passage 21c, the right passage 21d, and the left passage 21e, respectively, so as to evacuate in a cross-sectional direction perpendicular to the direction.

The second evacuation zone 25
The resin thermometers 39 to 41 as temperature measuring means for measuring the temperature of each part in the cross-sectional direction of the molded article 30 are provided on the front side in the flow direction of the lower part 21 to the lower part 21c and the right side passage 21d. , And on both sides of the left passage 21e, and is connected to the vacuum pressure control unit 29.

The vacuum pressure control unit 29 opens and closes the connected solenoid valves 33 to 35 in accordance with the temperatures detected by the resin thermometers 39 to 41, and opens and closes the vacuum slits 36 to 38. Are configured to be individually variable.

Further, in the first embodiment, as shown in FIG. 1, a cutter 25 for cutting the molded product 30 into a predetermined length is provided downstream of the take-off device 22.

Next, the operation of the first embodiment will be described.

In the extruder 14 of the first embodiment and the molding method using the extruder 14, the extruder 1
When the molded product 30 extruded from the mold 9 is inserted into the mold body 21a of the cooling mold 21, first, the vacuum pump 28
Is activated, and the molded product 30 is moved by the vacuum slits 32 in the pre-evacuation zone 23 to the mold body 2.
It is sucked and adhered to the wall surface of the molded product passage 21b of 1a.

As a result, a predetermined amount of heat is taken by the wall surface of the molded article passage 21b, and the molded article 30 is cooled.

Next, the molded product 30 is transferred to the molded product passage 21.
b, the resin thermometers 39 to 41 are sequentially moved in the direction of the first to fourth evacuation zones 24 to 27 before the first to fourth evacuation zones 24 to 27. The resin temperature of each lower surface and the left and right surfaces is measured for each part.

The vacuum pressure control section 29 increases at least one of the vacuum pressure on the downstream side of the portion where the cooling is delayed and the vacuum pressure on the downstream side of the portion where the cooling is advanced. Or both controls are performed,
A control signal is sent to each of the solenoid valves 33 to 35 to open and close.

For this reason, the resin thermometers 39 to 4 on the front side are used.
The cooling amount is appropriately changed according to the temperature of each part of the molded article 30 measured in 1 to reduce the difference in shrinkage, thereby reducing the difference in shrinkage in each part in the cross-sectional direction. Thus, a molded product with good accuracy can be formed without generating distortion, warping, and the like.

[0042]

EXAMPLE A molded product 30 having a substantially U-shaped cross section was formed using a vinyl chloride resin material. At that time, the cooling mold 21 has a length of about 1000 mm, and the zone is constituted by five zones of a pre-evacuation zone 23 and first to fourth evacuation zones 24 to 27.

In this embodiment, each of the lower, right,
The vacuum pressure can be controlled according to the resin temperature for each of the inner and outer surfaces of the left side passages 21c to 21e.

[0044]

[Comparative Example] The cooling mold is composed of only one zone using cooling water as a medium, and the resin temperature measurement and the vacuum control are not performed.

As a result, in the above embodiment, the molded product 30
No warping or bending was observed, and a molded product with good precision was obtained.

On the other hand, in the comparative example, warping occurred on the side where cooling was delayed.

The first embodiment of the present invention has been described with reference to the drawings. However, the present invention is not limited to the first embodiment, and design changes within a scope that does not change the gist of the present invention. Even if there is, it is included in the present invention.

For example, in the first embodiment, the cooling mold 21 having five zones is used. However, the present invention is not limited to this.
One or more cooling zones may be provided, according to the temperature detected by the temperature measuring means, if configured to adjust the vacuum pressure, cooling temperature, the material of the resin material, the quantity, The shape is not particularly limited.

The vacuum slits 32,.
Are formed to have a groove shape. However, the present invention is not limited to this, and may be formed of a plurality of vacuum holes. The size, shape and the like are not particularly limited.

[0050]

As described above, according to the first aspect of the present invention, the vacuum pressure control is performed in accordance with the temperature of each part in the sectional direction of the molded article measured by the temperature measuring means. In the section, the vacuum pressure for evacuation is adjusted.

By adjusting the pressure of the evacuation, the degree of close contact with a mold provided around the periphery can be varied, and the cooling efficiency can be controlled.

For this reason, by appropriately changing the cooling amount according to the temperature of each part of the molded product measured by the temperature measuring means and reducing the difference in shrinkage, a molded product with good precision can be molded. .

According to the second aspect of the present invention, the vacuum pressure control unit increases the vacuum pressure on the downstream side of the part where the cooling is delayed, or increases the vacuum pressure on the downstream side of the part where the cooling is advanced. The vacuum pressure is reduced or at least one or both are controlled.

For this reason, by appropriately changing the cooling amount in accordance with the temperature of each part of the molded product measured by the temperature measuring means and reducing the difference in shrinkage, a molded product with good precision can be molded. , Which has a practically useful effect.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an overall configuration of an extrusion molding machine according to a first embodiment of the present invention.

FIG. 2 is a side view illustrating a configuration of a cooling mold of the extrusion molding machine according to the first embodiment.

FIG. 3 is a cross-sectional view illustrating a configuration of a cooling mold of the extrusion molding machine according to the first embodiment, taken along a line AA in FIG.

FIG. 4 is a vertical cross-sectional view illustrating a configuration of a conventional extrusion molding machine, taken along a molded product extrusion direction.

FIG. 5 is a cross-sectional view illustrating an example of an extruder and a molded article molded by a molding method using the extruder, taken along a plane orthogonal to a flow direction.

FIG. 6 is a graph showing a relationship between a cooling time and a resin temperature in each part of a molded product until a glass transition point is reached.

[Explanation of symbols]

 14 Extrusion molding machine 21 Cooling mold 24 to 27 First to fourth evacuation zone 29 Vacuum pressure control unit 30 Molded product 39 to 41 Resin thermometer (temperature measuring means)

Claims (2)

[Claims] 1. An extruder for extruding a molten resin into a mold to mold it into a molded product, and the extruded molded product is cooled by being evacuated and brought into close contact with a mold provided around the extruder. An extruder having a cooling mold to be cured, wherein the cooling mold is provided with a plurality of evacuation zones in a flow direction in which the molded product is extruded and moved and a cross-sectional direction orthogonal to the flow direction. At the same time, a temperature measuring means for measuring the temperature of each part in the sectional direction of the molded article is provided on the front side of each zone in the flow direction, and the vacuum pressure is adjusted according to the temperature detected by the temperature measuring means. An extrusion molding machine, comprising: 2. The vacuum pressure control section increases the vacuum pressure downstream of a portion where cooling is delayed, or decreases the vacuum pressure downstream of a portion where cooling is progressing. The molding method using an extruder according to claim 1, wherein both the controls are performed.