JPH06182856A - Blow molding die - Google Patents

Abstract

PURPOSE:To obtain a blow molding die in which an old residual resin adhering to a manifold formed in a core as a resin path can be smoothly removed. CONSTITUTION:Resin inlets are symmetrically opened. A manifold 20 is formed from one resin inlet to the surface of a core 16 so as to be peripherally branched rightward and leftward, decreased in path cross sectional area, and curved in an extrusion direction. The end of this manifold 20 is made confluent with the end of a manifold having the other resin inlet 22. Furthermore, the core 16 is peripherally split into a circular form in a plain view so as to each contain the resin inlet and the cofluent part. A slpit core drive mechanism is connected correspondingly to each of the split cores.

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 quite troublesome to remove it, and in such a case it was necessary to disassemble and clean the die body, so it is necessary to stop the entire line every time the resin is 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 inlets from the machine side are opened symmetrically, and each resin inlet is branched to the land surface of the cored bar to the left and right in the circumferential direction to reduce the passage cross-sectional area, and
A cored bar formed by forming a manifold curved in the extrusion direction, and joining the manifold end and the manifold end from the other resin inlet, respectively, and dividing the circumferential direction including the confluent part of the cored bar into an arc shape in plan view. In addition to providing the parts, the core metal splitting part drive mechanism is connected to each of the core metal splitting parts.

[0006]

[Operation] A cored bar division part including a confluent part at the end of the manifold where old resin is liable to adhere is provided so that it can be withdrawn from the cored bar main body, and this is forcibly withdrawn when the resin is replaced to remove the old resin, and then the original resin is again removed. Since the new resin and old resin are replaced by returning to the state of, 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 shows the structure of the die according to the embodiment.
This is applied to a flat parison injection die, and as shown in the figure, this die 10 has a die housing 12, and a through-hole 14 having a substantially oval cross section is bored along the longitudinal center line thereof. Has been done. Such a through hole 14
In the state where the equivalent diameter is gradually reduced from the middle to the lower end surface of the housing 12,
Is opened at the lower end surface of the. And the housing 1
A cored bar 16 having an oval cross-section, which has a smaller diameter than that of the through hole 14, is inserted into the inside of the through hole 2, and a resin passage 18 is provided between the outer peripheral surface of the cored bar 16 and the inner peripheral surface of the through hole 14. Is formed. An upper end portion of the cored bar 16 has a cross-sectional structure in close contact with the through-hole 14, and the resin passage 18 is formed in the lower part thereof.

The lower end of the cored bar 16 is formed so as to squeeze in accordance with the reduced diameter portion of the through-hole 14, and the parison control core 1 can be moved in and out from the cored bar 16 particularly at the tip end part.
6b is attached. The upper area of the core metal 16 is called a mandrel 16a and the lower area is called a core 16b.

A resin supply passage 21 is bored inside the core metal 16, and the resin supply passage 21 is branched in a diameter direction corresponding to the core metal 16 to open a pair in the resin passage 18. The opening is set in the resin passage 18 on the wide side of the flat die 10 as shown,
This is the resin inlet 22.

A semi-circle on the outer surface of the core metal 16 is branched from the respective resin inflow ports 22 to the left and right in the circumferential direction and is gradually curved in the extrusion direction with a predetermined curvature while gradually reducing the passage cross-sectional area at a predetermined rate. A manifold 20 having a cross section is formed. The end of the manifold 20 is approximately 18 from the manifold 20 on the opposite side and the resin inlet 22 which are symmetrical.
They are formed so as to join each other at a position of 0 degree. Then, a dam lip portion 31 forming a shallow passage along the circumferential direction of the core metal 16 is formed downstream after the opening of the confluence portion 27. 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 resin flowing down each manifold 20 are parallel at the merging portion.

The entire tubular passage extending from the lower edge of the manifold 20 to the dam lip portion 31 is
It is shallower than the cross-sectional depth of passage 0, and the dam lip 3
Land portion 33 forming a passage deeper than the depth of the flow passage in one portion
Is formed. This is formed by adjusting the scraping depth of the outer surface of the cored bar 16 as described above.

Further, the parison control core 1
A mandrel lip 29, which faces the opening of the through hole 14 and forms an oval resin discharge port 28 with the opening of the through hole 14, is integrally provided at the tip of 6b. 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 changing the die housing 1.
2 is made possible by driving the control cylinder 30 fixed to the support bracket 24 which is erected on the upper mounting plate 34.
A rod 32 connecting 0 and the parison control core 16b is passed through the core metal 16.

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.
In addition, in order to be able to perform it in a short time, each of the cored bar main bodies has a cored bar splitting part 35, which includes a confluent part 27 located on the long diameter side of the elliptical cored bar 16 and has a circumferential direction divided into an arc in a plan view. It is built in 16 and is as follows. The cored bar splitting section 35 is composed of a right cored bar splitting section 35a located on the front right side in FIG. 1 and a left cored bar splitting section 35b located on the front left side.

The left and right mandrel split parts 35b, 35a and the mandrel main body 16 are joined to each other at the lower edge thereof with an L-shaped step groove 37, which is slidable at the joining part. The housing 12 and the cored bar body 16 are engaged and closely contacted with each other so as to be vertically movable. The left and right mandrel split parts 35b, 35a are independently movable, and therefore a drive mechanism is connected to each of the left and right mandrel split parts 35b, 35a.

The hydraulic cylinder 38 (3
8a, 38b) drive rod 40 which is expanded and contracted.
(40a, 40b) to the left and right core metal splitting parts 35 (35
b, 35a) is connected to the upper end surface. These hydraulic cylinders 38a, 38b utilize the support bracket 24,
It is installed on a pedestal 50 attached to this.

When the parison 45 is extruded without changing the resin, the left and right mandrel split parts 35 are displaced from the mandrel main body 16 by sliding at the joints, and the left and right mandrel split parts 35 are formed. So that it does not rise naturally, the fixed block 47 having an inverted L-shaped cross section is fixed to the die housing 12 with bolts or the like.
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 resin inlet 21 through the resin passage 21 from an extruder (not shown)
At 0, it branches to the left and right to reach the merging section 27, and at the same time as the branch flow down,
3, and the resin 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.

At the time of exchanging the new and old resins after such a series of extrusion operations, first, the plasticizing measurement by the extruder and the injection of the parison 45 are repeated several times, and most of the new and old mixed resins are melted to some extent in advance. Replace with resin. Next, the bolts holding the fixing block 47 are removed, and the piston rods 40a, 4 of the hydraulic cylinders 38a, 38b are removed.
The pressure oil is introduced to the 0b side, and the left and right core bar split parts 35b, 3
5a is raised to the upper limit. Under this condition, the old resin adhering to and remaining on the manifold 20 of the left and right cored bar split portions 35b, 35a is forcibly removed using, for example, a wire brush attached to a portable or fixed device. It is something to do.

After the work of removing the old resin is completed, pressure oil is introduced into the piston head side of the hydraulic cylinders 38a and 38b to lower the left and right core metal split portions 35b and 35a, and as shown in FIG. It is engaged with the substantially L-shaped step groove 37 so as to be integrally formed with the main body 16. Next, the fixing block 47 is fixed again with bolts, and new resin is repeatedly supplied from the extruder 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. The resin inlets of are opened symmetrically, and from each resin inlet to the land surface of the core metal,
A manifold that is branched to the left and right in the circumferential direction, has a reduced passage cross-sectional area, and is curved in the extrusion direction is formed. The manifold end and the manifold end from the other resin inlet are joined together, and the joining portion of the core metal is By providing a cored bar splitting part that divides the included circumferential direction into an arc shape in a plan view, and connecting a cored bar splitting part drive mechanism to each of these cored bar splits, the entire die can be Unlike disassembly and cleaning, removal of old resin is easy, reliable, and can be done in a short time, has little effect on other devices and work, and significantly increases the operating rate of the device.

[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 perspective view showing a mounting state of a cored bar split portion on a cored bar.

[Explanation of symbols]

 10 dice 12 die housing 14 through-hole 16 core metal 16a mandrel 16b core 18,21 resin passage 20 manifold 22 resin inlet 27 confluence portion 28 resin discharge port 30 control cylinder 31 dam lip portion 33 land portion 35 core metal dividing portion 35a right Part cored bar split part 35b Left part cored bar split part 38 (38a, 38b) Hydraulic cylinder 40 (40a, 40b) Drive rod 45 Parison 47 Fixed block

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Claims (1)

[Claims] 1. A core metal is inserted into a die housing to form a resin passage, a resin inlet from the extruder side is opened in a symmetrical position in the resin passage, and a land of the core is provided from each resin inlet. On the surface of the part, a manifold is formed which is branched to the left and right in the circumferential direction and has a reduced passage cross-sectional area, and is curved in the extrusion direction. The manifold end and the manifold end from the other resin inlet are joined together to form the core metal. A blower characterized in that a cored bar splitting part, which is divided into a circular arc shape in a plan view in the circumferential direction including the merging part, is provided, and a cored bar splitting part drive mechanism is connected to each of the cored bar splits. Molding die.