JP2019177564A - Blow molded body manufacturing apparatus and manufacturing method - Google Patents

Abstract

To shorten a tact time in manufacturing of a blow molded article having an undercut portion.SOLUTION: A manufacturing apparatus 20 of a blow molding 10 includes a pair of molds 22 for surrounding a parison 11 and forming a welded portion 16 by flattening a part of the parison 11. A dome portion 13 (end part in an axial direction) of the blow molding 10 is formed by a part connected to the welded portion 16 in the parison 11 and an undercut portion 15 is formed in the dome portion 13. A pair of molds 22 includes: a pair of mold bodies 23; and a pair of nests 32 forming the undercut portion 15 in a state where the entire region of the welded portion 16 is sandwiched. The pair of nests 32 can be detached from the pair of mold bodies 23 while remaining in one piece with the blow molding 10.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a blow molded article manufacturing apparatus and manufacturing method.

  Patent Document 1 discloses a method for producing a blow molded article. In blow molding, a cylindrical parison extruded from an extruder is accommodated in a pair of molds that are opened in a direction crossing the axis of the parison, and the accommodated parison is expanded to form a mold. Press against the surface and mold into a predetermined shape. When the blow molded body begins to harden in the mold and the shape of the blow molded body becomes stable, at that stage, the mold is opened and the blow molded body is taken out, and the taken out blow molded body is cooled outside the mold. . If the blow molded body is cooled outside the mold, the next blow molding can be performed with the vacant mold while one blow molded body is being cooled. Thus, the production efficiency can be improved.

JP 07-214653 A

  In a blow-molded product, when a base is inserted into a gear-shaped groove at an end portion in the axial direction and the liner and the base are rotated in synchronization, the gear-shaped groove is undercut. When forming such an undercut part, a part of metal mold | die is made into a slide type | mold, and an undercut part is formed with the molding surface of a slide type | mold. However, when the slide mold is used, the blow molded body cannot be cooled outside the mold for the following reason.

  When the pair of molds are clamped, a part of the parison is flattened and welded flat by the mold, and the part of the parison that is connected to the welded portion constitutes the axial end of the blow molded body. Since the end portion in the axial direction is a portion where the undercut portion is formed, the slide mold that forms the undercut portion sandwiches the welded portion of the parison. Therefore, if the slide mold is opened while the blow molded body is not sufficiently cured, the welded portion sandwiched between the slide molds may be deformed into an incorrect shape by pulling the axial end of the blow molded body. End up. In order to avoid this, it is necessary to sufficiently cool the blow molded body inside the mold and solidify it to a state where there is no risk of deformation before starting the mold opening. End up.

  The present invention has been completed based on the above-described circumstances, and an object thereof is to shorten the tact time in the manufacture of a blow molded article in which an undercut portion is formed.

The blow molded body manufacturing apparatus according to the first invention is:
Surrounding and molding the parison which is the material of the blow molded body, and comprising a pair of molds forming a welded portion by flattening part of the parison,
An axial end portion of the blow molded body is formed by a portion connected to the welded portion of the parison, and a manufacturing apparatus that forms an undercut portion at the axial end portion,
A pair of mold bodies in which the pair of molds are opened in a direction crossing the axial direction of the parison, and a pair of nestings that form the undercut portion in a state where the entire region of the welded portion is sandwiched And configured with
The pair of nests is characterized in that the pair of inserts can be detached from the pair of mold main bodies while being integrated with the blow molded body.

The manufacturing method of the blow molded article according to the second invention is
Using a pair of molds that surround and mold the parison, which is the material of the blow molded body, and form a welded portion by flattening part of the parison,
An axial end portion of the blow molded article is formed by a portion connected to the welded portion of the parison, and an undercut portion is formed at the axial end portion,
On the pair of molds, a pair of inserts can be attached to and detached from a pair of mold main bodies opened in a direction intersecting the axial direction of the parison,
The undercut portion is formed in a state where the entire region of the welded portion is sandwiched by the pair of inserts,
The pair of inserts and the blow molded body before solidification are separated from the pair of mold main bodies in an integrated state.

  After the parison is molded by clamping the pair of molds, before the blow molded body is solidified, the insert and the blow molded body are detached from the mold main body in an integrated state and cooled. During this time, the welded portion connected to the end portion in the axial direction of the blow molded body is kept in a state of being sandwiched by a nesting integrated with the blow molded body, so that even if the blow molded body is detached from the mold body, There is no possibility that the end of the axial direction of the wire will be distorted. The nesting may be removed from the blow molded body after the blow molded body is cooled and solidified. While the blow molded body is being cooled, another blow molded body can be manufactured at the same time by attaching another insert to the mold body, so that the tact time can be shortened.

Partially cutaway front view showing a state in which the mold is opened in Example 1 and the parison is pushed out Front sectional view showing a state where a blow molded body is molded by clamping the mold Side sectional view showing the state where the mold is clamped to form the blow molded body Partially cutaway front view showing the blow molded body and insert integrated and detached from the mold body Partially cutaway front view showing the state where the insert is removed from the blow molded product

  In the first and second inventions, a cooling flow path for allowing the refrigerant to flow may be provided in the insert. According to this configuration, the time required for cooling and hardening the end portion in the axial direction of the blow-molded product can be shortened, so that the tact time can be further shortened.

  In the first and second aspects of the present invention, the mold body may be provided with a holding member that is locked to the insert and can hold the insert in a predetermined mounting position with respect to the mold body. According to this configuration, since the nest can be positioned at an appropriate position with respect to the mold body, the blow molded body can be molded with high accuracy.

<Example 1>
A first embodiment of the present invention will be described below with reference to FIGS. In the following description, for the up and down directions, the directions appearing in FIGS. The vertical direction and the axial direction are used synonymously. For the left-right direction, the directions appearing in FIGS. 1, 2, 4 and 5 are defined as left and right as they are.

  The blow molded body 10 of this embodiment is a member that is manufactured by a blow molding method using the manufacturing apparatus 20 and is used as a liner of a pressure vessel. As an example of the material of the blow molded body 10, a mixed resin of high density polyethylene (HDPE) and ethylene / vinyl alcohol copolymer resin (EVOH) can be used. The blow molded body 10 includes a cylindrical body portion 12, a dome portion 13 (an end portion in the axial direction described in the claims) bulged upward from the upper end of the body portion 12, and a lower portion from the lower end of the body portion 12. It is comprised from the dome part 13 (the axial direction edge part as described in a claim) of the form bulged to the side. The trunk | drum 12 has comprised the cylindrical shape which orient | assigned the axis line to the up-down direction (vertical direction).

  A cylindrical portion 14 for attaching a base (not shown) is formed in a central portion of the upper dome portion 13 so as to protrude upward. An undercut portion 15 having a circular shape in plan view and recessed downward is formed in a region surrounding the cylindrical portion 14 concentrically in the upper dome portion 13. This undercut part 15 is formed in the axial direction edge part of the blow molded object 10, for example, is a gear-shaped groove | channel. By fitting a base (not shown) to the undercut portion 15, the blow molded body 10 and the base can be rotated in synchronization. A cylindrical portion 14 for attaching a base (not shown) is also formed in the center portion of the lower dome portion 13 so as to protrude downward. An undercut portion 15 having an annular shape in bottom view and recessed upward is also formed in a region surrounding the cylindrical portion 14 concentrically in the lower dome portion 13.

  The manufacturing apparatus 20 includes a blow molding machine 21 and a pair of symmetrical molds 22. The blow molding machine 21 is disposed above the mold 22 and pushes out the cylindrical parison 11 as a material of the blow molded body 10 downward in the vertical direction.

  The pair of molds 22 is for molding the parison 11 into a blow molded body 10 having a predetermined shape in a clamped state. The pair of molds 22 includes a pair of mold main bodies 23 and two pairs of inserts 32. The pair of mold main bodies 23 face each other in parallel with the mold clamping and mold opening directions of the mold 22. Each mold body 23 is formed with a cavity 24 having a concave surface facing the mold body 23 on the other side. The inner surface of the cavity 24 is a first molding surface 25 for molding the entire region on the outer circumferential surface of the body portion 12 and the outer peripheral edge portion on the outer surface of the dome portion 13 into a predetermined shape. The pair of mold main bodies 23 are clamped concentrically with the parison 11 by approaching in the left-right direction, and opened by separating in the left-right direction.

  The upper and lower ends of each mold body 23 are respectively formed with receiving recesses 26 in the form of recessing the facing surface of the counterpart mold body 23. The accommodation recess 26 on the upper end side is disposed above the cavity 24 and communicates with the upper end portion of the cavity 24. The accommodation recess 26 on the lower end side is disposed below the cavity 24 and communicates with the lower end portion of the cavity 24. The nest 32 is accommodated in the accommodating recess 26.

  The upper end and the lower end of the mold body 23 are respectively provided with a first support hole 27 penetrating in a horizontal direction from the outer surface of the mold body 23 to the receiving recess 26 and from the outer surface of the mold body 23 to the receiving recess 26. A second support hole 28 penetrating in the direction is formed. Each first support hole 27 is attached with a pin-shaped first holding member 29 (holding member described in claims), and each second support hole 28 is respectively provided with a pin-shaped second holding member. 30 (a holding member described in claims) is attached. The first holding member 29 and the second holding member 30 include a locking position (see FIGS. 1 and 2) in which the distal end portion of each holding member is advanced into the accommodation recess 26, and a gold without being advanced into the accommodation recess 26 It is movable between a retreat position (not shown) that retreats inside the mold body 23.

  The nesting 32 forms a pair of the molds 22 facing each other in parallel with the mold clamping and mold opening directions of the mold 22. Each insert 32 is a member that can be individually attached to and detached from the mold main body 23, and is attached to the mold main body 23 in a state of being fitted in the housing recess 26. The nest 32 has a second molding surface 33 that faces the cavity 24 in a state of being attached to the receiving recess 26. The outer peripheral edge of the second molding surface 33 is continuous with the upper end or the lower end of the first molding surface 25. The 2nd shaping | molding surface 33 shape | molds the whole area | region of the center side rather than an outer periphery part among the outer surfaces of the dome part 13 in a predetermined shape. Specifically, the entire area of the undercut portion 15 and the cylindrical portion 14 are formed.

  Of each nesting 32, a surface facing the counterpart nesting 32 that forms a pair with the nesting 32 is a pressing surface 34. The clamping surface 34 includes a plane orthogonal to the mold opening and clamping directions of the mold 22. The pinching surface 34 is continuous with the second molding surface 33 at an angle close to a right angle. Further, the width dimension of the pinching surface 34 (the dimension in the horizontal direction orthogonal to the axis of the parison 11) is set to a dimension larger than ½ of the circumferential length of the parison 11.

  The nest 32 includes a horizontal first locking hole 35 that is coaxially connected to the first support hole 27 in a state of being fitted to the receiving recess 26, and a second support hole 28 that is fitted to the receiving recess 26. And a horizontal second locking hole 36 communicating coaxially. In a state where the insert 32 is attached at an appropriate position in the housing recess 26, the front end portion of the first holding member 29 can be fitted into the first locking hole 35, and the second holding member 30 can be inserted into the second locking hole 36. The front end can be inserted. Further, the nest 32 is formed with a cooling channel 37 communicating with a channel (not shown) formed in the mold body 23. A cooling medium (for example, cooling water) for cooling the insert 32 flows through the cooling flow path 37.

  Next, the manufacturing procedure of the blow molded body 10 will be described. As shown in FIG. 1, in each mold 22, the insert 32 is accommodated in the accommodating recess 26 of each mold body 23, and the distal end portion of the first holding member 29 is fitted into the first locking hole 35. At the same time, the tip of the second holding member 30 is fitted into the second locking hole 36. By fitting the holding members 29, 30 and the locking holes 35, 36, the nest 32 is positioned and assembled to the mold body 23 at a normal position, and the detachment from the mold body 23 is restricted. Is kept in the state. Thereby, the mold 22 is ready for molding.

  Thereafter, the parison 11 is pushed out between the two molds 22 with the mold 22 opened. When the parison 11 having a predetermined length is pushed out, the pair of molds 22 are brought close to each other and clamped. At this time, the mold main body 23 and the two nestings 32 attached to the mold main body 23 move together horizontally. When the mold is clamped, the parison 11 is surrounded by the pair of molds 22 and accommodated in the housing.

  After the mold clamping, the parison 11 in the cavity 24 is inflated by an air supply means (not shown) and pressed against the first molding surface 25 and the second molding surface 33. Thereby, the blow molded body 10 molded into a predetermined shape is obtained. Immediately after the parison 11 is pressed against the first molding surface 25 and the second molding surface 33, the blow-molded body 10 is not sufficiently cured, so that it can be deformed when subjected to an external force. However, since the insert 32 is cooled by the refrigerant flowing through the cooling flow path 37, the dome portion 13 in contact with the insert 32 in the blow molded body 10 is cooled.

  When the shape of the blow molded body 10 is stabilized by cooling, the first holding member 29 and the second holding member 30 are moved to the retracted position to be removed from the first locking hole 35 and the second locking hole 36, and a pair of The mold is opened so that only the mold body 23 is separated from the left and right. However, the time from when the parison 11 is pressed against the first molding surface 25 and the second molding surface 33 to when the mold is opened is relatively short. Therefore, the degree of cure of the blow molded article 10 at the time of mold opening is such that the blow molded article 10 can be easily deformed when an external force is applied to the blow molded article 10.

  Therefore, when the mold body 23 is opened, the nest 32 is not detached from the blow molded body 10 and remains integral with the dome portion 13. The reason why the nesting 32 and the blow molded body 10 are kept integral is as follows. When the mold 22 is clamped, a part of the parison 11 (a part above the cavity 24 and a part below the cavity 24) is sandwiched between the clamping surfaces 34 of the nest 32 forming a pair. It is crushed flat and welded. The welded portion 16 of the parison 11 is connected to the dome portion 13 and has a form projecting in a plate shape from the outer surface of the dome portion 13 in the axial direction or the radial direction.

  Therefore, when the insert 32 is to be detached from the blow molded body 10 (dome portion 13) that is not sufficiently cured, the welded portion 16 sandwiched between the inserts 32 pulls the dome portion 13. Therefore, the blow molded body 10 (dome portion 13) is illegally deformed. In order to avoid such a situation, when the curing of the blow molded body 10 is not sufficiently advanced, only the mold body 23 is opened, and the insert 32 is left integrated with the dome portion 13. I will leave it.

  The blow molded body 10 is removed from the mold main body 23 and moved to a cooling booth (not shown) in a state where the insert 32 is integrated with the dome portion 13 and the weld portion 16 (see FIG. 4). Cool by hanging. After the blow molded body 10 is sufficiently cooled and solidified, the insert 32 is separated from the blow molded body 10 in the axial direction (upward or downward). The manufacturing process of the blow molded body 10 is thus completed.

  While the blow molded body 10 is being cooled, the mold 22 is configured by attaching another insert 32 to the mold body 23 in the mold open state, and the mold 22 is used to mold another parison 11. be able to. That is, the process of cooling the blow molded body 10 and the process of molding the blow molded body 10 in the mold 22 can be performed simultaneously.

  The blow molding body 10 manufacturing apparatus 20 of the present embodiment surrounds and molds the parison 11 that is the material of the blow molding body 10, and forms a welded portion 16 by flattening part of the parison 11 flatly. A mold 22 is provided. And according to the manufacturing method of a present Example, while using the manufacturing apparatus 20, while forming the dome part 13 (axial direction edge part) of the blow molded object 10 by the part connected to the welding part 16 among the parison 11, An undercut portion 15 is formed in the dome portion 13.

  The pair of molds 22 forms a pair of mold main bodies 23 opened in the left-right direction intersecting the axial direction of the parison 11 and the undercut portion 15 in a state where the entire region of the welded portion 16 is sandwiched therebetween. A pair of inserts 32 is provided. The two pairs of nests 32 can be detached from the pair of mold main bodies 23 while being in an integral state with the blow molded body 10 that is not sufficiently cured.

  According to the manufacturing apparatus 20 and the manufacturing method of the present embodiment, after the parison 11 is formed by clamping the pair of molds 22 and before the blow molded body 10 is solidified, the insert 32 and the blow molded body 10 are integrated. In this state, it is detached from the mold body 23 and cooled. During this time, the welded portion 16 connected to the dome portion 13 of the blow molded body 10 is held between the inserts 32 integrated with the blow molded body 10, so that the blow molded body 10 is detached from the mold body 23. However, the dome portion 13 will not be distorted. The insert 32 may be detached from the blow molded body 10 after the blow molded body 10 is cooled and solidified. While the blow molded body 10 is being cooled, the production of another blow molded body 10 can be simultaneously performed by attaching another insert 32 to the mold body 23, so that the tact time can be shortened.

  Further, since the nest 32 is provided with the cooling flow path 37 for allowing the refrigerant to flow, the time required for cooling and hardening the dome portion 13 of the blow molded body 10 can be shortened. Thereby, the tact time can be further shortened. In addition, the mold body 23 is provided with holding members 29 and 30 that can be held in a predetermined mounting position with respect to the mold body 23 by being locked to the insert 32. According to this configuration, the insert 32 is positioned at an appropriate position with respect to the mold body 23, and the positional relationship between the first molding surface 25 and the second molding surface 33 can be appropriately maintained with high accuracy. 10 can be molded with high accuracy.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the holding member for positioning the nest is provided in the mold body. However, such a holding member may not be provided, and the nest may be fitted into the groove or the recess of the mold body.
(2) In the above embodiment, the cooling channel for cooling the insert is formed in the mold body, but the cooling channel may be formed in the holding member.
(3) In the above embodiment, the mold is provided with the cooling flow path for cooling the insert. However, the mold may not have the cooling flow path.
(4) In the above embodiment, the pair of inserts and the pair of mold main bodies are integrally clamped, but the welded portion is formed with the parison sandwiched between the pair of inserts, and then a pair of inserts is formed. The mold body may be clamped.
(5) In the above embodiment, the pair of inserts are separated from the blow molded body in parallel with the axial direction, but the direction of separating the pair of inserts from the blow molded body is the mold opening of the pair of mold bodies. The direction may intersect with both the direction and the axial direction of the blow molded body.
(6) In the above embodiment, two pairs of nestings are attached to a pair of mold bodies, but only one pair of nestings may be attached to a pair of mold bodies.

10 ... Blow molding 11 ... Parison 13 ... Dome part (end in axial direction)
DESCRIPTION OF SYMBOLS 15 ... Undercut part 16 ... Welding part 20 ... Manufacturing apparatus 22 ... Mold 23 ... Mold main body 32 ... Nest 29 ... 1st holding member (holding member)
30: Second holding member (holding member)
37 ... Cooling channel

Claims (4)

Surrounding and molding the parison which is the material of the blow molded body, and comprising a pair of molds forming a welded portion by flattening part of the parison,
An axial end portion of the blow molded body is formed by a portion connected to the welded portion of the parison, and a manufacturing apparatus that forms an undercut portion at the axial end portion,
The pair of molds is
A pair of mold bodies that are opened in a direction intersecting the axial direction of the parison;
A pair of inserts that form the undercut portion in a state of sandwiching the entire area of the welded portion;
The blow molded body manufacturing apparatus according to claim 1, wherein the pair of inserts is detachable from the pair of mold main bodies while being integrated with the blow molded body.   The blow molded body manufacturing apparatus according to claim 1, wherein a cooling flow path for allowing the refrigerant to flow is provided in the nest.   3. A holding member capable of being engaged with the insert and holding the insert in a predetermined mounting position with respect to the mold body is provided on the mold body. An apparatus for producing the blow molded article. Using a pair of molds that surround and mold the parison, which is the material of the blow molded body, and form a welded portion by flattening part of the parison,
An axial end portion of the blow molded article is formed by a portion connected to the welded portion of the parison, and an undercut portion is formed at the axial end portion,
On the pair of molds, a pair of inserts can be attached to and detached from a pair of mold main bodies opened in a direction intersecting the axial direction of the parison,
The undercut portion is formed in a state where the entire region of the welded portion is sandwiched by the pair of inserts,
A method for producing a blow molded article, wherein the pair of inserts and the blow molded article before solidification are separated from the pair of mold main bodies in an integrated state.

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