JPH06170926A - Blow molding die - Google Patents

Abstract

PURPOSE:To provide a blow molding die removing smoothly old resin which is stuck to and left behind in a manifold forming a resin passage by a core metal. CONSTITUTION:A die 10 wherein a resin passage is formed by inserting a core metal into a die housing, a manifold 20 which is bent in an extruding direction while reducing a sectional area of the passage by facing opposite to resin-inflow port side of the core metal by opening a resin inflow port 21 from an extruding machine 23 side within the resin passage and branching right and left in a circumferential direction from the surface of the core metal on the resin inflow 21 side is formed and a confluent part 27 is formed by allowing manifold 20 ends from the resin inflow port 21 side to meet is used. Furthermore, circumferential directions of the resin inflow port 21 side and a confluent part 27 side are divided into a circular-arc shape by viewing plainly and core metal divided part driving mechanisms are connected with each other by corresponding to each of respective divided core metals 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding machine, and more particularly, to a blow molding die which facilitates resin change (material change and color change).

[0002]

2. Description of the Related Art Conventionally, when changing resin,
As a method of replacing the old resin remaining in the die with the new resin to be used next, a method of extruding the old resin fluidly by supplying the new resin from the upstream part of the old resin is generally used. is there. However, due to the nature of the fluid, the new resin easily passes through the center of the passage, and a large amount of new resin and a long time are required to extrude the old resin adhering to the passage wall surface. Also, when molding a cylindrical parison, there is a structural resin confluence part inside the die, and the retention of this part further deteriorates the efficiency of color change, and insufficient material change corresponds to this confluence part. This results in a decrease in the strength of the product and deterioration of the surface quality due to the residual resin on the surface of the parison.

[0003]

In the above-mentioned prior art, it is particularly difficult to completely remove the deteriorated resin from the confluent portion, and even when the resin is replaced, the resin remaining between the inner walls of the core metal is completely removed. It is a rather troublesome work to remove, and in such a case, the die body had to be disassembled for cleaning, so it was necessary to stop the entire line every time the material was changed. However, there was a problem that the operation rate of the equipment was also reduced.

In view of the above conventional problems, it is an object of the present invention to provide a blow molding die capable of smoothly removing old resin adhering to and remaining on a manifold forming a resin passage formed on a core metal. To do.

[0005]

In order to solve such a problem, in a blow molding die according to the present invention, a core metal is inserted into a die housing to form a resin passage, and the resin is extruded into the resin passage. The resin inlet from the machine side is opened, and the resin is branched in the circumferential direction from the surface of the core on the resin inlet side to the left and right in the circumferential direction, and the passage cross-sectional area is reduced toward the resin inlet side of the core in the extrusion direction. A die that forms a curved manifold and joins the manifold ends from the resin inlet side to form a merging portion, wherein the circumferential direction of the core on the resin inlet side and the merging portion side is a circle in plan view. Divided into arcs,
In this structure, a driving mechanism for a split portion of the cored bar is connected to each of the split cored bars.

[0006]

[Function] The resin inflow side where the old resin is apt to remain and the confluent part at a position of approximately 180 degrees from this resin inflow side are provided with a cored bar dividing part that can be pulled out from the cored bar main body, and this is forced when changing the resin. Since the old resin is removed and the old resin is returned to the original state to replace the new resin with the old resin, the time required for resin replacement is significantly shortened and the old resin is reliably removed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the blow molding die according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a blow molding die 1 according to an embodiment.
FIG. The die 10 has a die housing 12 made of a rectangular block, and a through-hole 14 having a substantially circular cross section is bored along the vertical center line. Such a through hole 14 is opened in the lower end surface of the housing 12 in a state where the inner diameter is gradually reduced from the middle to the lower end surface of the housing 12.

A through hole 14 is formed in the housing 12.
The core metal 16 having a smaller diameter is inserted, and the core metal 1
6 between the outer peripheral surface of 6 and the inner peripheral surface of the through hole 14
Is formed. The lower end of the cored bar 16 is formed so as to be narrowed in accordance with the reduced diameter portion of the through-hole 14, and a parison control core 16b is attached to the tip end so that the parison 16 can be moved in and out. The upper area of the core metal 16 is called a mandrel 16a and the lower area is called a core 16b.

A mandrel lip 29 is integrally provided at the tip of the parison control core 16b so as to face the opening of the through-hole 14 and form a circular ring-shaped resin discharge port 28 between the opening of the through-hole 14 and the parison control core 16b. Has been. Therefore, the die gap of the resin discharge port 28 can be arbitrarily changed by changing the in / out amount of the parison control core 16b.

The die gap is changed by the die housing 1.
This is made possible by driving a control cylinder 30 fixed to a support plate 24 provided upright on the support plate 24. Therefore, a rod 32 connecting the control cylinder 30 and the parison control core 16b is made to penetrate the core metal 16. There is.

In addition, the resin passage 22 for connecting the extruder 23 provided on the peripheral wall of the die housing 12 to the resin inlet 21
First, the molten resin supplied to the core metal 16 is branched to the left and right in the circumferential direction of the core metal 16 to form a manifold 20 having a semicircular cross section that is curved in the extrusion direction with a predetermined curvature while gradually reducing the passage cross-sectional area at a predetermined ratio. is doing. The end of the manifold 20 is formed so as to join with the symmetrical manifold 20 on the opposite surface side at a position of approximately 180 degrees from the resin inlet 21.

Corresponding to the confluence portion 27, a dam lip portion 31 forming a shallow passage is formed along the circumferential direction of the core metal 16. The dam lip portion 31 is provided corresponding to the throttle passage portion of the resin passage 18, and is set so that the gap between the dam passage portion 31 and the through hole 14 of the housing 12 is narrowed so that the flow passage resistance is uniform over the entire circumference. ing.
In this case, the merging portion 27 is connected and merged so that the manifolds 20 having merging symmetry are in contact with the line along the axis of the core metal 16. As a result, the flow lines of the molten resin flowing down the manifold 20 are parallel at the merging portion.

The entire resin passage 18 extending from the lower edge of the manifold 20 to the dam lip portion 31 is shallower than the passage sectional depth of the manifold 20 portion and forms a passage deeper than the passage depth of the dam lip portion 31 portion. The part 33 is formed. This is formed by adjusting the scraping depth of the outer periphery of the cored bar 16 as described above.

In the present invention, it is easy to change the resin (that is, change the material or change the color) of the blow molding die 10.
And the resin inlet 2 of the core metal 16 so that it can be done in a short time.
The cored bar dividing parts 35, which respectively include the first side and the confluence part 27 and which are divided in an arc shape in the circumferential direction in a plan view, are incorporated in the cored bar 16 main body, respectively, and are as follows. The cored bar splitting portion 35 is composed of a front cored bar splitting portion 35a located on the resin inlet 21 side and a rear cored bar splitting portion 35b located on the merging portion 27 side.

The front and rear core metal splitting portions 35a and 35b and the core metal main body 16 are split and joined to each other.
Are formed and are in close contact with each other so that they can move up and down between the die housing 12 and the core metal body 16 while sliding at the joints. Such a front / rear core metal split portion 3
5a and 35b can be moved independently, so
A drive mechanism is connected to each of the rear core metal split portions 35a and 35b.

The hydraulic cylinder 38 (3
8a, 38b) drive rod 40 which is expanded and contracted.
(40a, 40b) to each front / rear core metal split portion 35 (35
a, 35b). The hydraulic cylinders 38a and 38b are mounted on a pedestal 50 attached to the support plate 24 using the support plate 24.

When the parison 45 is extruded without changing the resin, the front and rear core metal split portions 35 are displaced from each other by sliding at the joint portions from the core metal main body 16 and the front and rear core metal split portions 35 naturally move. The fixed block 47 having an inverted L-shaped cross section is fixed to the die housing 12 with bolts or the like so as not to rise.
It is attached to. The fixed block 47 has a structure that can be divided into two in the circumferential direction.

The operation of the die part configured as described above will be described. The molten resin flowing from the extruder 23 through the resin passage 22 through the resin inlet 21 is branched left and right in the manifold 20 to reach the confluent portion 27, and the branched resin is sequentially flown down from the lower edge of the manifold 20 to the land portion 33. The resin overflows and flows uniformly over the entire circumference of the resin passage 18. Since the groove cross-sectional area of the manifold 20 is set to be gradually reduced, the pressure distribution in the circumferential direction becomes uniform and the dam lip portion 31 flows down in a state of being readjusted to have a uniform wall thickness. It is ejected as a parison 45.

When exchanging the new and old resins after such a series of extrusion operations, first, the plasticizing and metering by the extruder 23 and the injection of the parison 45 are repeated several times, and most of the new and old mixed resins are updated to some extent in advance. Replace with molten resin. next,
The bolts holding the fixing block 47 are removed, and the piston rods 40 of the hydraulic cylinders 38a, 38b are removed.
Introducing pressure oil to the a and 40b sides to separate the front and rear core metal split parts 35
Increase a and 35b to the upper limit. Under this condition
The old resin adhered and remaining on the manifold 20 of the rear core metal split parts 35a and 35b is forcibly removed by using, for example, a wire brush that is portable or attached to a certain device.

After the removal of the old resin is completed, pressure oil is introduced to the piston head side of the hydraulic cylinders 38a and 38b to lower the front and rear core metal split portions 35a and 35b, and as shown in FIG. It is engaged with the L-shaped step groove 37 so as to be integrally formed with 16. Next, the fixing block 47 is fixed again with bolts, and new resin is repeatedly supplied from the extruder 23 to the die 10 side to perform resin change (color change or material change) until the new and old resins are completely replaced.

[0022]

As is apparent from the above description, in the blow molding die according to the present invention, the core metal is inserted into the die housing to form the resin passage, and the resin passage is formed from the extruder side. Manifold which opens the resin inflow port, and branches from the surface of the core metal on the resin inflow port side in the circumferential direction to the left and right in the circumferential direction, curving in the extrusion direction while reducing the passage cross-sectional area toward the opposite resin inflow port side of the core metal. To form
A die in which the manifold ends from the resin inlet side are joined to form a merging portion, and the circumferential direction of the core metal on the resin inlet side and the merging portion side is divided into arcs in plan view, and each division is divided. Unlike the conventional method of disassembling and cleaning the entire die, the old resin can be removed easily, surely, and in a short time by connecting the driving mechanism of the core metal division to each core metal. , The influence on other devices and work is small, and the operating rate of the device is significantly increased.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a die showing an embodiment according to the present invention.

FIG. 2 is a plan view seen from AA in FIG.

FIG. 3 is a perspective view showing a mounted state of a cored bar divided portion on a cored bar.

[Explanation of symbols]

 10 dice 12 die housing 14 through-hole 16 core metal 16a mandrel 16b core 18 resin passage 20 manifold 21 resin inlet 22 resin passage 23 extruder 27 merge part 28 resin discharge port 30 control cylinder 35 core metal split part 35a front core Gold splitting part 35b Rear core metal splitting part 38 (38a, 38b) Hydraulic cylinder 40 (40a, 40b) Drive rod 45 Parison 47 Fixed block

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area // B29L 22:00 4F

Claims (1)

[Claims] 1. A core metal is inserted into a die housing to form a resin passage, and a resin inlet from the extruder side is opened in the resin passage, and a core metal surface on the resin inlet side is arranged in a circumferential direction. A manifold that branches left and right and that curves in the extrusion direction while reducing the passage cross-sectional area toward the resin inlet side of the core metal is formed, and the manifold ends from the resin inlet side are joined to form a merging portion. In the die, the circumferential direction of the resin inflow side and the merging side of the cored bar is divided into arcs in a plan view, and the cored bar division drive mechanism is connected to each of the divided cored bars. A blow molding die characterized in that