JPH06254954A - Blow molding machine - Google Patents

Abstract

PURPOSE:To provide a blow molding machine which is capable of separating/ uncoupling molding burrs from a large-size parison or a flat parison easily and facilitating a recycle process. CONSTITUTION:The subject blow molding machine is equipped with a blade-type protrusion 20 which is formed for carving out a V notch which subdivides and cuts molding burrs vertically and horizontally. These burrs generate on the surface of a die around the cavity 8a of the die 8 during die clamping.

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 for producing hollow products from large parisons or flat parisons, and more particularly to a blow molding machine for efficiently treating molding burrs.

[0002]

2. Description of the Related Art In blow molding in which a hollow resin product is made from a parison that is cylindrically injected or extruded from a die head, a parison is injected or extruded from the die head and pre-blown into a bag-shaped parison by a parison pinch. After inflating slightly, put it in an open mold and close the mold, and after degassing the gas in the cavity formed by the mold and parison, a vacuum pump device from a small air vent hole leading to the mold surface After suctioning air through the, the parison is blown into the parison with high pressure to form the parison into a predetermined shape based on the cavity and then cooled with a die to complete the molding. The resin product thus molded is taken out by opening the mold. The thing shown in FIG. 4 shows the conventional blow molding machine. 4 shows a so-called side-feed type blow molding machine 1 in which molten resin is supplied from one side of the die head 2, and the resin in a high temperature molten state pressed by the extruder 4 is the resin supply port 2a. And passes through an annular passage provided between the die head 2 and the mandrel 3 and is discharged from the annular space passage 7 at the lowermost end to form a parison P. A passage 2b and a valve 5 (or a plug) provided outside the passage 2b are disposed at a position 180 ° apart from the resin supply port 2a of the die head 2.
The core 3a is connected to a Parison rod 6a penetrating the mandrel 3 and is slightly moved up and down by the operation of the Parison cylinder 6 to control the wall thickness of the parison P. ) Can be adjusted.

[0003]

In the blow molding method in such a conventional blow molding machine, there is a flat burr called a molding burr around a molding portion sandwiched between both molds and formed along the cavity of the mold. After the molding is completed and the mold is finished, both dies are opened to separate the product and the molding burr. It was At this time, a large burr formed by a large parison or a flat parison also has a large forming burr, and it is inevitable that the forming burr is divided into small segments for recycling.

[0004]

[Means for Solving the Problems] In order to solve the above problems and to easily and conveniently process large molding burrs, in the blow molding machine of the present invention, a core attached to the lower ends of the die head and mandrel is used. In a blow molding machine for forming a hollow product by sandwiching a parison discharged from an annular resin passage between a mold and a pair of left and right molds, a mold is formed on a mold surface surrounding a cavity of both molds. A blade-like protrusion was formed to engrave a V notch that divides the molding burr formed around the cavity during tightening into vertical and horizontal sections.

[0005]

In the blow molding machine of the present invention, the blade-shaped projections are formed on the surface of the mold forming the molding burr around the cavity of the mold so as to engrave V notches that divide the molding burr vertically and horizontally. The molding burr after opening is easily separated into a plurality of subdivided segments. Therefore, these separated segments can easily be recycled.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 relate to an embodiment of the present invention,
1 is a perspective view of a mold, FIG. 2 is an enlarged cross-sectional plan view of a main part of the mold, and FIG. 3 is a cross-sectional plan view of a molded body. As shown in the figure, blade-shaped projections 20 running in a grid pattern are provided on the mold surfaces around the cavities 8a of the pair of left and right molds 8, 8. In the embodiment of FIG. 2 (a), the blade-like protrusion 20 has a trapezoidal shape with a thin tip, and the blade-like protrusions 20 of the pair of left and right molds 8, 8 are arranged at the same position, and the mold clamping is performed. The blade-shaped projections 20, 20 facing each other at times are configured to maintain a clearance of about 2 to 5 mm. In the embodiment of FIG. 2B, only one of the molds 8 and 8 is provided with a trapezoidal or triangular blade-shaped protrusion 20 having a sharp tip, and the other mold 8 is a flat smooth surface and has a blade-shaped protrusion 20. Is not provided, and the tip of the blade-shaped projection 20 of one mold is lightly contacted with the surface of the other mold during mold clamping. 2 (a) and 2 (b), the die 8 having the blade-shaped projections 20 has the blade-shaped projections 2 on the entire surface of the die except the cavity 8a, as shown in FIG.
0s are arranged in a cross pattern vertically and horizontally. Other configurations of the blow molding machine 1 except the mold 8 are the same as conventional ones, and therefore the description thereof will be omitted.

The mold has a parting part (pinch-off part)
There is a part that divides the molded product and the molding burr called
Due to the action of this parting portion, as shown in FIG. 3, a depression is formed along the boundary line between the molded product and the molding burr.
Since the outer periphery of the cavity surface of the mold is generally curved, the parting portion is also curved. A curve formed by the parting part is called a parting line 8b.

The operation of the blow molding machine 1 equipped with the molds 8 and 8 having the blade-like projections 20 will be described. In the embodiment shown in FIG. 2A, the parison P is cooled after the mold is clamped and molded. As shown in FIG. 3, the body 30 is in a state in which the molding burr 32 is divided into squares or rectangles by the V notches 40 and can be easily divided. Further, in the embodiment of FIG. 2B, since the blade-shaped projection 20 of one mold 8 is brought into contact with the surface of the other mold 8 during mold clamping, the molding burr 32 is completely removed during mold clamping. It is cut, and the cut rectangular segment separates and falls by the mold opening.

As described above, according to the present invention, by forming the blade-shaped projections 20 on the surface of the mold, the molding burr 32 is removed from the molded body 30 after molding or is easily separated and separated. Is in a state of earning, and
The molding burrs 32 to be separated are almost unified in the size of a postcard, which is convenient for the recycling process.

[0010]

As described above, in the blow molding machine of the present invention, since the molding burr can be easily removed, the process is simplified and the separated molding burr can be easily recycled.

[Brief description of drawings]

FIG. 1 is a perspective view of a mold according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional plan view of a main part of a mold according to an embodiment of the present invention.

FIG. 3 is a cross-sectional plan view of a molded body according to an example of the present invention.

FIG. 4 is a vertical sectional view of a conventional blow molding machine.

[Explanation of symbols]

 1 Blow Molding Machine 2 Die Head 2a Resin Supply Port 3 Mandrel 4 Extruder 5 Valve 6 Paricon Cylinder 6a Paricon Rod 7 Annular Space Passage 8 Mold 8a Cavity 8b Parting Line 20 Edge Protrusion 30 Molded Body 32 Molding Burr 40 V Notch P parison

Claims (1)

[Claims] 1. A blow molding machine for forming a hollow product by sandwiching a parison discharged from an annular resin passage between a die head and a core attached to a lower end of a mandrel with a pair of left and right molds to produce a hollow product. A blow molding machine in which a blade-like protrusion is formed on the surface of the mold surrounding the cavity of the mold to form V notches that divide the molding burr formed around the cavity when the mold is clamped into vertical and horizontal sections.