JPH06126812A - Blow molding method and device - Google Patents

Abstract

PURPOSE:To manufacture efficiently a molded product bent in two-dimensions or three-dimensions. CONSTITUTION:A guide cavity part D possessing a conical face DI where a hole diameter becomes large gradually toward the inside and a main body cavity part C continuing to the lower end side of the guide cavity part D are formed in a mold 10. A head member 12 which can inject molten resin as cylindrical parison 14 is arranged on the upper part of the meld. A nozzle 16 and bent assembly 22 are arranged so as to be capable of going in and out through an opening to parison 14 injected into a mold which is on a mold break position. The bent assembly 22 is made capable of performing free suspension and bendable into a predetermined form. Since the bent assembly is bent within the parison, the parison 14 is premolded in accordance with a cavity and since comprssed fluid is blot into the mold-clamped parison 14 through a nozzle 16, a molded product 14a having a guide part 114b on a mouth side is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding method and apparatus.

[0002]

2. Description of the Related Art As a conventional blow molding method for molding a two-dimensionally or three-dimensionally bent molded article, Japanese Unexamined Patent Publication (Kokai) No. Hei 3
There is one such as that disclosed in Japanese Laid-Open Patent Publication No. 240516. In the blow molding method shown therein, a bending assembly obtained by splicing a plurality of bending members with a plurality of wires is used as a core for preforming. The bending assembly has a free hanging shape when the wire is loosened,
When the wire is strained, the axial center of the wire is bent into a two-dimensional or three-dimensional shape to have a predetermined shape. The bending assembly is positioned between the open molds in a linear shape with free hanging, and the parison is injected so as to surround the outer periphery of the bending assembly. The parison is then preformed into a predetermined shape by bending the bending assembly. Next, the mold is closed and pressurized fluid such as air is supplied into the parison to perform the final molding, and then the bending assembly is returned to a freely deformable state so that it can be removed from the molded product. . Thereby, a two-dimensionally or three-dimensionally bent molded product can be molded, and the bent assembly can be repeatedly used as a preforming core.

[0003]

However, in the conventional blow molding method as described above, since the mouth of the molded product is molded by the opening of the mold,
Since the diameter of the nozzle for supplying the pressurized fluid into the parison must correspond to the diameter of the mouth of the molded product, it is necessary to prepare a large number of nozzles with different diameters. Also, there is a problem that every time the diameter dimension of the mouth of the molded product changes, it is necessary to replace the nozzle with a diameter dimension corresponding to this. The present invention aims to solve such problems.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a cavity of a mold is provided with a guide cavity portion whose hole cross-sectional area gradually increases from the opening to the inside, and is bent two-dimensionally or three-dimensionally so as to be continuous with the guide cavity portion. The above problem can be solved by configuring the main body cavity portion. That is, the blow molding method of the present invention comprises a guide cavity portion having a conical surface whose cross-sectional area gradually expands inward from the die opening portion, and a main body cavity portion which is continuously bent in two or three dimensions. Open the mold in which is formed, and if a plurality of bending members are spliced together with a plurality of wire members to loosen the wire member, it becomes freely deformable, and if the wire member is tensioned, it becomes a predetermined shape. Position the flexing assembly configured to flex in the mold in a free hanging state, then inject a parison so as to surround the perimeter of the flexing assembly, and then flex the flexing assembly into a predetermined shape. Pre-forms the parison into a predetermined shape, then closes the mold and supplies pressurized fluid from the nozzle into the parison to guide the parison into the shape of the cavity and body cavity. The guide assembly and the molded product that correspond to the shape of the body are integrally molded, and then the bending assembly that is freely deformable is extracted through the molded product and the guide unit, and then the mold is opened. Then, the molded product with the guide portion is taken out, and then the guide portion is separated to obtain a molded product.
Further, the apparatus for carrying out the above method comprises a head member (12) capable of extruding a parison (14), an openable and closable mold (10) disposed below the head member (1), and a head member (1).
A bending assembly (22) arranged on the side 2) and capable of entering and leaving the parison (14), and a nozzle capable of injecting a compressed fluid into the parison (14) in the mold cavity closed. (16), and the bending assembly (22) loosens the wire members (20a, 20b) by splicing the plurality of bending members (18) with the plurality of wire members (20a, 20b). In the case where the wire member (20a, 20b) is configured to be freely deformable and bent to a predetermined shape when the wire members (20a, 20b) are tensioned, the mold (10) The cavity has a guide cavity portion (D) having a conical surface (D1) whose cross-sectional area expands from the opening (10a) toward the inside of the mold, and is bent two-dimensionally or three-dimensionally continuously with this. Body And a tee portion (C).
In addition, a pinch device (24) capable of pressing one end side of the parison (14) in the axial direction to make a sealed state is provided between the mold (10) and the head member (12). I hope you are there. The reference numerals in parentheses indicate the corresponding members of the embodiment.

[0005]

The molten resin is injected as a cylindrical parison from the annular resin passage of the head member and positioned in the opened mold. The flexure assembly is then placed in the parison with the linear free hang. Next, the parison is preformed by bending the bending assembly into a predetermined two-dimensional or three-dimensional shape, and the mold is closed and clamped. Next, a compressed fluid is blown into the parison from a nozzle attached to the bending assembly for final molding. Thereby, the guide part corresponding to the guide cavity part of the mold and the molded product corresponding to the main body cavity part are integrally molded. That is, a molded product having the guide portion formed on the upper portion is obtained. With the bending assembly again in the free hanging state, pull out from the molded product and the guide part. At this time, the bending assembly is smoothly guided from the large-diameter portion to the small-diameter portion of the guide portion, so that the pulling-out operation is not disturbed. Next, the mold is fully opened, and the molded product with the guide portion is taken out from the mold. Next, in a separating step, the guide portion is separated from the molded product. This allows
Finally, it is possible to manufacture a molded product having a predetermined shape that is bent two-dimensionally or three-dimensionally. Since the inner diameter of the mouth of the guide cavity can be arbitrarily determined, it is only necessary to prepare one nozzle having a predetermined outer diameter, and to prepare a large number of nozzles having different outer diameters as in the conventional case. No need.

[0006]

EXAMPLE FIG. 1 shows an example of the present invention. A head member 12 is arranged above the die 10 in the figure. The head member 12 is supported by an injection device (not shown). The cavity of the mold 10 is a guide cavity D formed from the opening 10a on the upper surface of the mold in the figure to the inside of the lower part, and a molded product continuous with the lower end side of the guide cavity D (bent in two or three dimensions). And a main body cavity portion C corresponding to the shape of. That is, the cavity has a body cavity C at the lower end of the guide cavity D.
Are connected to each other. The guide cavity portion D will be described in detail later. The mold 10 is divided into two parts, a left part and a right part, in the figure, and is driven by respective mold opening and closing devices (not shown) so that the mold closing position shown in the drawing and the leftward and rightward directions from the closed position are shown. It is possible to locate them in the mold open position which has been moved respectively. An annular resin extrusion port is formed in the head member 12 described above. The resin passage of the injection device (not shown) is the head member 12
It communicates with the resin extrusion port. The molten resin can be injected as a cylindrical parison 14 downward in the drawing from the resin extrusion port of the head member 12 through the injection device. Head member 12
A nozzle 16 is arranged in a center hole formed in the axial center of the. The nozzle 16 is driven by a nozzle driving device (not shown) so as to be movable between the illustrated air blowing position and an ascending position above the drawing position. At the lower part of the nozzle 16 in the drawing, a bending assembly 22 is arranged, which is formed by splicing a plurality of bending members 18 together with wires 20a and 20b. The bending member 18 is made of a material that is difficult to adhere to other resin such as tetrafluoroethylene resin at least on the outer side, and the maximum diameter dimension a of the bending member 18 is the nozzle 16
The relational dimension is smaller than the diameter dimension b. This allows the bending assembly 22 to easily pass through the mouth of the guide cavity D when the bending assembly 22 is pulled out from the molded product 14a or the like in the mold 10 as described later. The wires 20a and 20b are respectively connected to a wire driving device (not shown), and by being driven by the wire driving device, the splicing portion is brought into a loosened state or a tensioned state. When the wires 20a and 20b are loosened, the bending assembly 22 can have a linear free hanging shape, and when the wires 20a and 20b are tensioned, the bending assembly 22 is two-dimensional or It is possible to have a predetermined shape that is three-dimensionally bent. Two pinch devices 24 are arranged above the die 10 in the figure so as to sandwich the parison 14 at a position outside the nozzle 16. The pinch member 24a of the pinch device 24 has a semi-cylindrical recess corresponding to the outer diameter of the nozzle, and can be moved between the pinch position shown and a standby position outside the pinch position. ing. The pinch member 24 a pushes the parison 14 of a predetermined length extruded from the head member 12 toward the nozzle 16 to move the parison 14 a.
The inner diameter portion and the outer diameter portion of the nozzle 16 can be tightly adhered to each other. The nozzle 16 is connected to an air source (not shown), and compressed air can be blown into the preformed parison 14 in the illustrated air blowing position. Thereby, the parison 14 can be molded into a shape corresponding to the guide cavity portion D and the main body cavity portion C.
In the pinch position shown, the pinch device 24 described above
It is possible to prevent the compressed air blown into the parison 14 from the nozzle 16 from leaking to the outside. Mold 10 described above
The guide cavity portion D is formed by a conical hole-shaped guide surface D1 having a substantially conical hole shape in which the hole inner diameter gradually increases from the opening 10a toward the bottom surface of the mold, and a connection guide surface D2 continuous with the conical hole-shaped guide surface D1. ing. The lower end of the connection guide surface D2 in the figure is smoothly connected to the inlet C1 of the cavity body C. By forming the guide cavity portion D into such a guide surface shape, as will be described later, after the molding process is completed, the bending assembly 22 allows the bending assembly 22 to have the inner peripheral surface of the molded product 14a, the connection guide surface D2 and the conical hole guide surface D1. Will be guided to the mold 1 smoothly and smoothly
It is designed to be pulled out to zero.

Next, the operation of this embodiment will be described. The mold 10 is located at a mold open position in the left-right direction in the drawing rather than the mold closed position shown in the drawing. In the pinch device 24, the pinch portions 24a of the pinch device 24 are respectively retracted to the standby positions outside the pinch position shown in the drawing. The nozzle 16 is located at a raised position above the illustrated position. Further, a wire driving device (not shown) is driven to position the bending assembly 22 between the molds 10 in a state where the bending assembly 22 hangs down linearly. Molten resin is accumulated in a storage chamber (not shown) of the head member 12 through an injection device (not shown). The molten resin accumulated in the storage chamber is opened at a predetermined timing from the annular hole of the head member 12 as a cylindrical parison 14 into the mold 10 in the mold open state.
It is extruded so as to surround the outer periphery of the bending assembly 22. When the parison 14 is extruded by a predetermined length, the injection process ends, and the process of accumulating the molten resin in the storage chamber starts in preparation for the next process. In this state, a wire driving device (not shown) is driven to tension the wires 20a and 20b, whereby the bending assembly 22 has a predetermined shape bent in two dimensions or three dimensions as illustrated. ,
In response to this, the parison 14 is also forced into a bent state. That is, the parison 14 is preformed into a predetermined shape. At this time, the bending assembly 22 is partially
It comes into contact with the inner peripheral wall surface (however, the contact portion is not visible at the cross-sectional position shown in the drawing), and the deformation force is applied to the parison 14, but the outer portion is made of a material such as tetrafluoroethylene resin. Since it is formed of, it will not adhere to the parison 14. Next, a mold closing step is performed, and the pinch portion 24a of the pinch device 24 advances from the standby position to the pinch position shown in the figure. As a result, the outer peripheral portion of the nozzle 16 and the inner peripheral portion of the parison 14 are hermetically sealed. In this state, compressed air is supplied from the air source (not shown) into the parison 14 through the nozzle 16. As a result, the parison 14 is pressed against the wall surface of the guide cavity portion D and the wall surface of the cavity C, and molding is performed. That is, the parison 14 has a shape in which the molded product 14a having a predetermined shape is formed below the guide portion 14b corresponding to the connection guide surface D2 and the conical hole guide surface D1.

Next, the pinch portion 24a of the pinch device 24.
Retreat to the standby position outside the illustrated position again, and the mold 10 reaches the halfway position of the mold (usually about 50 mm).
The mold is opened. In this state, the wires 20a and 20b are changed from the tensioned state to the loosened state, so that the bending assembly 2
No. 2 is in a free hanging state, and is pulled up to a raised position together with the nozzle 16. That is, the bending assembly 22 is pulled out from the guide portion 14b and the molded product 14a. At this time, the bending assembly 22 is guided from the large diameter portion to the small diameter portion by the guide portion 14b, and the opening portion 10a of the die 10 is guided.
Can be smoothly moved out of the mold 10. Guide part 14
Since the molded product 14a with b can change its posture to some extent within the mold half opened, the bending assembly 2
The withdrawal of 2 can be made easier. Since the outer diameter dimension of the nozzle 16 is set to be sufficiently larger than the outer diameter dimension of the bending assembly 22, the opening 1 of the mold 10 is
The movement of the bending assembly 22 is not obstructed by 0a. After pulling out the bending assembly 22, the mold 1
0 is fully opened, and the molded product 14a with the guide portion 14b is taken out. Next, in the separating step, the guide portion 14b is separated from the molded product 14a. As a result, the molded product 14a bent into a two-dimensional or three-dimensional predetermined shape is finally obtained. Incidentally, in blow molding, burrs are generally formed at the mouth of the molded product, and even in the conventional case, the burrs are cut off in the cutting step, so that the number of working steps of the present invention is However, the amount of waste material to be discarded is slightly increased. When the mold is replaced and a molded product having a different mouth portion size and bending shape is formed, the nozzle 16 can be simply replaced by replacing the mold and the bending assembly.
Also, molding can be performed without replacing the pinch portion 24a of the pinch device 24. Further, it is not necessary to change the mounting position of the pinch device 24.

[0009]

As described above, according to the present invention, it is possible to perform molding without replacing the nozzle when replacing the mold, and it is possible to improve the efficiency of the setup changing work. Since the degree of freedom in designing the mold opening can be increased and the nozzle diameter can be made sufficiently larger than the bending assembly diameter, the work of pulling out the bending assembly for preforming from the molded product bent in two dimensions or three dimensions Can be facilitated. When the pinch device is provided, it is not necessary to replace the pinch portion of the pinch device or change the mounting position when replacing the mold.

[Brief description of drawings]

FIG. 1 is a view showing a blow molding device of the present invention.

[Explanation of symbols]

 10 Mold 10a Opening 14 Parison 14a Molded Product 14b Guide 16 Nozzle 22 Bending Assembly 24 Pinch Device C Main Body Cavity D Guide Cavity D1 Conical Surface a Maximum Diameter of Bending Assembly b Outer Diameter of Nozzle

Claims (3)

[Claims] 1. A guide cavity portion having a conical surface whose cross-sectional area gradually expands inward from a die opening, and a main body cavity portion which is continuous with the guide cavity portion and which is bent two-dimensionally or three-dimensionally. When the mold is opened and a plurality of bending members are spliced together with a plurality of wire members to loosen the wire members, it becomes freely deformable, and when the wire members are tensioned, they are bent into a predetermined shape. Position the configured bending assembly in the mold in a free hanging state,
Next, the parison is injected so as to surround the outer periphery of the bending assembly, and then the parison is preformed into a predetermined shape by bending the bending assembly into a predetermined shape, and then the mold is closed and the parison is discharged from the nozzle. By supplying pressurized fluid to the inside, the parison was molded into a shape in which the guide part and the molded product corresponding to the shape of the guide cavity and the shape of the main body cavity were integrated, and then made into a freely deformable state. A blow molding method in which a bending assembly is pulled out through a molded product and a guide portion, then the mold is opened to take out a molded product with a guide portion, and then the guide portion is separated to obtain a molded product. 2. A head member (12) capable of extruding a parison (14), a mold (10) which can be opened and closed below this, and a parison which is arranged on the head member (12) side. A bending assembly (22) capable of moving in and out of (14), and a nozzle (16) capable of injecting a compressed fluid into a parison (14) in a mold cavity closed. And the bending assembly (22)
A plurality of bending members (18) are connected to a plurality of wire members (20a,
20b) splice together the wire members (20a,
In a blow molding machine configured to be freely deformable when loosening 20b) and bend to a predetermined shape when the wire members (20a, 20b) are strained, The cavity of 10) has a conical surface (D) whose cross-sectional area increases from the opening (10a) toward the inside of the mold.
A blow molding device comprising a guide cavity portion (D) having (1) and a main body cavity portion (C) which is continuously and continuously bent in two or three dimensions. 3. A pinch device (2) capable of pressing one end side of a parison (14) in the axial direction to make a sealed state.
The blow molding apparatus according to claim 2, wherein 4) is provided between the mold (10) and the head member (12).