JP2002178394A - Boring method of blow molded item and blow molding mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow molding mold for making e.g. a hollow resin product from a parison which can reduce cost in making a hole on a wall surface of the resin product by avoiding an additional boring process. SOLUTION: There are mounted on a blow molding mold 3 of a blow molding machine a slidable slide plate forming a part of a cavity and a boring guide hole 6 in a direction approximately perpendicular to the sliding direction of the slide plate 5, a boring drill 7 being mounted in the guide hole to protrude into and withdraw from the resin product in the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for piercing a blow molded product in a blow molding machine for producing a hollow resin product from a parison, for example, and a blow molding die therefor.

[0002]

2. Description of the Related Art Conventionally, in blow molding, as shown in FIG. 4, a parison p extruded into a cylindrical shape from a die head 2 is closed in a bag shape by a parison pinch, and the bag-shaped parison p is pre-blown. And slightly hung between the left and right molds 3 and 3 as shown in FIG. After degassing
The air is sucked out of the cavity by the vacuum pump device from the air vent hole that leads to the mold surface, and at the same time,
High-pressure air is blown into the parison p to expand the parison p. After the parison p is formed into a predetermined shape by the cavity, the parison p is cooled and solidified by the molds 3 and 3 to complete the forming. Thereafter, the resin molded product 8 formed by opening the molds 3 and 3 to the left and right is released.

When the resin molded product 8 needs an outlet hole for discharging a content liquid or the like when it is used as a container, the resin molded product 8 is placed in a mold 3.
After being removed from the mold, for example, the work is set in a tool and drilling is performed with a drill.

[0004]

However, the drilling operation is a separate step as a drilling step after the blow molding step, and the number of steps is increased, which is troublesome and increases the cost. The blow molding method and blow molding die according to the present invention are proposed to solve such problems.

[0005]

The gist of the present invention for solving the above-mentioned problems of the method for piercing a blow-molded article according to the present invention is to provide a slidable slide plate for forming a part of a cavity in a mold of a blow-molding machine. And a guide hole for perforation is provided in a direction substantially perpendicular to the direction in which the slide plate is slid, and a drill for perforation is provided in the guide hole so as to be able to come and go in the resin molded product in the mold. After forming a mold for blow molding, the parison is closed and the mold is inflated, then the slide plate is retracted, and the drill for punching is rotated while being advanced to the resin molded product side,
This is to form a hole in the wall surface of the resin molded product.

The gist of the blow molding die according to the present invention is to provide a slidable slide plate which forms a part of a cavity, and to form a hole for punching in a direction substantially perpendicular to a direction in which the slide plate is slid. A guide hole is provided, and a drill for drilling is provided in the guide hole so as to be able to come and go in a resin molded product in a mold. Further, the drill for drilling includes a drill bit having a cylindrical cutting edge and an engaging portion projecting from a central portion and having an engaging portion for holding and extracting a wall surface drilled at a tip portion thereof.

According to the method for piercing a blow molded article and the mold for blow molding according to the present invention, at the time of molding the parison, the slide plate is retracted almost simultaneously with cooling of the mold, and is provided in the piercing guide hole. The drill for drilling is advanced while rotating, and a hole is drilled in the wall surface of the molded resin molded product. The formed member in the hole portion is held by the cutting edge of the drill, and is discharged from the mold when the drill is retracted.

Further, according to the blow molding die of the present invention, the drilling operation is performed during the cooling period until the resin molded product is released from the die. Therefore, the perforation is performed in parallel with the cooling step of the molded product, so that the perforating step is completed without particularly extending the work period of the molding step. Since the drill is provided with the drill blade so as to hold the perforated wall surface, there is no possibility that the perforated wall surface falls into the resin molded product.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a method for piercing a blow molded product and a mold for blow molding according to the present invention will be described with reference to the drawings. To facilitate understanding of the present invention, portions corresponding to those of the conventional example will be denoted by the same reference numerals as those of the conventional example.

As shown in FIGS. 1 and 2, the molds 3 and 3 which open and close in the blow molding machine 1 are slidable to form a part of a cavity provided to form a molded product having a desired shape. The slide plate 5 is provided, and a guide hole 6 for punching is provided in a direction b substantially perpendicular to the direction a in which the slide plate 5 slides, and a drill 7 for punching the guide hole 6 in the die. The blow molding die 3 is provided so as to be able to come and go in the resin molded product 8.

The width of the slide plate 5 is at least the same as or larger than the diameter of the guide hole 6. As shown in FIG. 3, the drill 7 for drilling has a bit having a cylindrical cutting edge 7a and an engaging portion for holding and extracting a wall 8a protruding from the center and drilled at the tip 7b. 7c.

A method of piercing a wall surface of a resin molded product using the blow molding die 3 configured as described above is as follows.
At first, similarly to the conventional example, as shown in FIG. 4, the parison p is extruded from the die head 2, the molds 3 and 3 are closed so as to sandwich the parison p, the air in the cavity is sucked, and the inside of the parison p is The high pressure air is blown into the air to inflate it.

Thereafter, as shown in FIG. 1, the slide plate 5 is retracted downward in the figure. Then, as shown in FIG. 2, the drill 7 for drilling is advanced toward the resin molded product 8 and is rotated in a predetermined direction.

In the bit of the drill 7 for drilling, the tip of the engaging portion 7c of the drill bit at the center is slightly protruded from the end surface of the cutting edge 7a, and the resin molded product is formed first by the engaging portion 7c. A hole is made in the wall surface of 8, and a cylindrical cutting edge 7a subsequently makes a hole. Then, after the hole is penetrated, the drill 7 is retracted. The perforated wall surface 8a of the resin molded product 8 is engaged with the engaging portion 7c of the bit, and is taken out of the resin molded product 8 as the drill 7 retreats.

Thereafter, the molds 3 and 3 are opened right and left, and the resin molded product 8 is released. The above-mentioned hole has already been formed in the wall surface of the resin molded product 8. The above-described perforation process is performed during the cooling period of the mold 3 after the parison p is expanded, so that the production process period by the mold is not substantially extended.

[0016]

As described above, according to the method for piercing a blow-molded article according to the present invention, a slidable slide plate forming a part of a cavity is provided in a mold of a blow molding machine, and the slide plate is provided. A guide hole for punching is provided in a direction substantially perpendicular to the direction in which the slide is made, and a drill for punching is formed in the guide hole so as to be able to protrude and retract into a resin molded product in the mold. Then, after the parison is closed and the mold is inflated, the slide plate is retracted, and the drill is rotated while the drill for drilling is advanced to the resin molded product side, and a hole is formed in the wall surface of the resin molded product. Therefore, it is possible to complete the drilling step in the manufacturing process using the mold, and it is possible to obtain an excellent effect that the labor for drilling holes in a separate step can be omitted.

The blow molding die of the present invention is provided with a slidable slide plate forming a part of a cavity, and a guide hole for punching in a direction substantially perpendicular to a direction in which the slide plate is slid. Since a drill for piercing is provided in the guide hole so as to be able to protrude and retract from the resin molded product in the mold, it is possible to perform a hole forming operation on the resin molded product in the mold. Further, since the drill for drilling comprises a cylindrical cutting edge, and a drill blade having an engaging portion that protrudes from the center portion and holds and removes a wall surface that is drilled at the distal end portion, the drilling portion is made of resin. It can be automatically extracted from the molded product.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a part of a blow molding die according to the present invention.

FIG. 2 is an explanatory view showing a state of a hole punching operation by a blow molding die according to the present invention.

FIGS. 3A and 3B are enlarged explanatory views (A) and (B) of a bit portion of a drill in the blow molding die according to the present invention.

FIG. 4 is an explanatory view showing a method of using a blow molding die according to a conventional example.

FIG. 5 is an explanatory view showing a method of using a blow molding die according to the conventional example.

[Explanation of symbols]

1 blow molding machine, 2 die head, 3 molds, 5
Slide plate, 6 guide holes for drilling, 7 drills for drilling,
7a cutting edge, 7b tip, 7c engaging part, 8 resin molded product, 8a wall surface, p parison.

Claims (3)

[Claims] In a mold of a blow molding machine, a slidable slide plate forming a part of a cavity is provided, and a guide hole for punching is provided in a direction substantially perpendicular to a direction in which the slide plate is slid. Forming a blow molding die in which a drill for punching is provided in the guide hole so as to be able to protrude and retract from the resin molded product in the die, and after the parison is closed and the die is expanded, the slide plate is removed. Retracting and rotating a drill for drilling while moving the drill toward the resin molded product side to form a hole in the wall surface of the resin molded product. 2. A mold for use in a blow molding machine, wherein a slide plate slidably forming a part of a cavity is provided, and a guide hole for drilling is provided in a direction substantially orthogonal to a direction in which the slide plate is slid. A blow molding die, characterized in that a drill for punching is provided in the guide hole so as to be able to protrude and retract from a resin molded product in the die. 3. A drill for drilling, comprising: a cylindrical cutting edge; and a drill blade having an engaging portion protruding from a center portion and holding and extracting a wall surface perforated at a tip portion thereof. The blow molding die according to claim 2.