JP2003112360A - Method for blow molding hollow container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for blow molding a hollow container which has excellent appearance and functions while assuring moldability, a strength and the like by regulating a preblowing shape for receiving and delivering a parison by and to a split mold and in which occurrence of a flash can be suppressed. SOLUTION: The method for blow molding the hollow container comprises the steps of pinching the bottom of the parison 3 supplied to the split mold 1, then controlling the pressure of a parison air supplied into the parison, regulating a preblowing shape for receiving and delivering the parison to the mold 1, and increasing (thickening) a necessary part instead of the parison having a predetermined diameter so far to receive and deliver the parison regulated in the preblowing shape from and to the mold. Thus, the decrease in the strength is suppressed while the moldability is assured, and the hollow container can be efficiently blow molded.

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 for a hollow container, and is capable of efficiently performing blow molding while ensuring moldability and the like without requiring a thick parison.

[0002]

Blow molding is widely used as a method of molding hollow containers and the like. A parison extruded from a die head is received by a pair of split molds that are opened, and the mold is closed to blow air. After that, the mold is opened and the product is taken out.

A blow molding apparatus for performing such blow molding is roughly classified according to the moving type of molds. A rotary type that moves a large number of molds in an annular shape and a plurality of molds that reciprocate linearly. There is a shuttle type that can handle various types of hollow containers, etc. It is suitable because it takes a short time and does not require manufacturing cost.

For example, in the case of forming a hollow container (handle bottle) having an integrated handle portion with this shuttle type blow molding device, a pair of split molds having a cavity having a shape corresponding to the handle bottle is formed into a parison. Move to the receiving position and keep the mold open, pinch the bottom of the parison extruded from the die head and inflate the parison with the parison air, receive the parison, move to the blow molding position and blow the blow air. Blow molding is performed, and then the mold is opened to take out the product.

[0005]

However, in the case of blow molding such a handle bottle, as shown in FIG. 9 schematically showing the relationship between the cavity of the split mold and the parison, the split mold 1 is In order to secure the moldability of the nozzle portion 2a and the handle portion 2b of the cavity 2, a large (thick) parison 3 is necessary, but when the large (thick) parison 3 is used, the pinch portion 3a at the bottom is removed. There is a risk that it will stick out from the bottom of the split mold 1 and lead to a decrease in appearance, a decrease in ESC resistance (environmental stress crack resistance), a decrease in drop strength, etc. For the actual molding, make the parison large (thick) and at the same time. The tilting mold is tilted with respect to the parison that is extruded vertically to ensure moldability.

Further, in the case of a product (vidicon product) integrally formed with a transparent portion (wind stripe) for confirming the remaining amount of the contents on the side of the handle bottle, the pinch portion at the bottom of the parison is If it protrudes from the bottom of the split mold, there is a problem that the transparent part is cut off in the middle of the side surface, which makes it impossible to make a product or reduces the function as a container.

Further, since it is necessary to use a large (thick) parison, there is also a problem in that there are many burrs other than the product.

The present invention has been made in order to solve the problems of the prior art. By adjusting the pre-blow shape to be transferred to the split mold of the parison, the formability and strength can be ensured while the appearance and appearance can be improved. An object of the present invention is to provide a blow molding method for a hollow container, which has an excellent function and can suppress the generation of burrs.

[0009]

In order to solve the above problems of the prior art, in the blow molding method for a hollow container according to claim 1 of the present invention, the split mold is moved to a parison receiving position where the parison is supplied. In the blow molding method of the hollow container, which receives the parison, closes the mold and blow-molds it at the blow molding position, pinches the bottom of the parison supplied to the split mold and then supplies the parison air to the inside of the parison. It is characterized in that the pre-blow shape to be controlled and delivered to the split mold is adjusted.

According to the blow molding method of this hollow container, after the bottom of the parison supplied to the split mold is pinched, the parison air supplied to the inside of the parison is controlled to adjust the pre-blow shape to be delivered to the split mold. By replacing the conventional parison with a constant diameter with a pre-blown shape adjusted parison, the parison is delivered to a split mold to ensure moldability while suppressing a decrease in strength, etc. Allows blow molding of containers.

The blow molding method for a hollow container according to a second aspect of the present invention is characterized in that, in addition to the structure according to the first aspect, the parison air is controlled by controlling the pressure of the parison air. Is.

According to the blow molding method of this hollow container, the control of the parison air is controlled by the pressure of the parison air, the diameter of the parison extruded from the die head can be changed, and the necessary portion can be enlarged ( By making it thicker, it becomes possible to form a pre-blow shape with excellent moldability.

Further, in the blow molding method for a hollow container according to claim 3 of the present invention, in addition to the structure according to claim 1 or 2, the pre-blow shape of the parison has a shape corresponding to the cavity shape of the split mold. It is characterized by adjusting to.

According to the blow molding method of this hollow container, the pre-blow shape of the parison is adjusted to a shape corresponding to the cavity shape of the split mold, whereby the moldability can be further improved and the parison is wasted. It becomes possible to suppress the occurrence of burr as much as possible.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a blow molding method for a hollow container according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a process diagram schematically showing a relationship between a cavity of a split mold and a parison according to an embodiment of a blow molding method for a hollow container of the present invention.

The blow molding method for this hollow container (hereinafter simply referred to as the blow molding method) is, for example, as shown in FIG.
For the parison extruded from the die head E, four split molds are arranged in two mold rows, and four parisons are arranged.
The parison is received at the parison receiving position and blow molding is performed by blowing blow air at the blow molding position while combining the B, C, and D split molds in the two moving directions x and y which are orthogonal to each other. It is applied to blow molding and adjusts the shape of the parison that is supplied to and delivered to the split mold at the parison receiving position.

That is, in this blow molding method, for example, a hollow container (handle bottle) in which a handle portion is integrally formed
Applied when blow molding, as shown in FIG.
A cavity 2 corresponding to the shape of the handle bottle is formed in the pair of split molds 1. This cavity 2 is
The nozzle portion 2a and the handle portion 2b are provided, and the nozzle portion 2a having the smallest diameter opening is arranged at the upper end portion.
A shoulder portion 2c is formed following a, and a body portion 2d is formed from the shoulder portion 2c to have a gradually larger diameter and then gradually narrows. A handle portion 2b is integrally formed with a maximum diameter portion on a side of the body portion 2d. And a closed flat bottom portion 2e is formed at the lower end portion.

The shape of the parison 3 supplied to the split mold 1 in which the cavity 2 having the above-mentioned respective portions 2a to 2e is formed is required to ensure moldability, so that the nozzle portion 2a and the handle portion 2b of the cavity 2 are formed. It is optimal that the parison 3 is placed in the cavity 2 and that the parison 3 does not protrude from the bottom 2e of the cavity 2. For example, as shown in FIG.
The parison 3 has a pinch portion 3a at the front end, the pin-shaped upper end 3b of the boring is the thinnest, the center of the middle part 3c is the thickest, and the lower end 3d is shaped to correspond to the shape of the thin cavity 2. There is a need.

Therefore, the shape of the parison 3 is adjusted by controlling the parison air so that the parison 3 corresponding to such a shape of the cavity 2 is supplied from the die head 4 to the split mold 1 and passed.

Usually, the parison 3 extruded from the die head 4 has a constant diameter, and the split mold 1 in the previous step is the parison 3.
When the parison 3 is cut, the bottom portion is pinched and closed at the pinch portion 3a after the parison 3 is cut, so that parison air is supplied into the parison 3 in order to pass the parison air to the next split mold 1 while maintaining the hollow state. Has become.

The control of the parison air is performed, for example, by temporally changing the pressure of the parison air, and adjusts the shape of the parison 3 by changing the amount of expansion of the parison 3 extruded with a constant diameter. Since the parison 3 can be inflated and the diameter can be increased by increasing the pressure of the parison 3, the pressure of the parison air is changed by changing the extrusion length L of the parison 3 (passage of time in the parison extruded at a constant speed) L. The shape corresponding to the shape of 2 is used.

For example, the maximum body diameter is 90 mm and the bottom diameter is 70 m.
m 720cc handle bottle molding cycle 14
In the case of blow molding as a second, after pinching the lower end of the parison 3 having a constant diameter of 60 mm extruded from the die head 4 and closing it with the pinch portion 3a, the pressure of the parison air is set to 3 Kpa from 1 to 3 seconds, By controlling the pressure to inflate the parison 3 by setting the pressure to 5 Kpa until the 4th to 9th seconds and further setting the pressure to 2Kpa until the 10th to 14th seconds, for example, as shown in FIGS. 1 (a) to 1 (c). , Parison 3 at the bottom and bottom 2 of body 2d of cavity 2
The part corresponding to e is finally inflated to a diameter of 65 mm,
Finally, the portions corresponding to the body portion 2d and the handle portion 2b are largely expanded to a diameter of 85 mm, and the nozzle portion 2
The part corresponding to a can finally remain 60 mm in diameter.

The shape of the parison 3 supplied into the split mold 1 by such pressure control of the parison air is shown in FIG.
As shown in (c), it is possible to adjust the shape to correspond to the cavity 2 of the split mold 1 of the handle bottle of 720 cc to the pin-shaped parison shape of the optimum boring.

When the pressure of the parison air is controlled to adjust the shape of the parison, the uppermost portion extruded from the die head has the highest temperature and tends to swell, and the extruded lowermost portion has the lower temperature and swells. Considering the difficulty and the fact that the entire parison extruded by the parison air expands (although the amount of expansion varies depending on the temperature and other conditions), it is necessary to determine the pressure of the parison air to control over time, and blow molding should be performed. It is decided as appropriate based on the results of experiments according to the product shape.

For example, when a 1000 cc handle bottle having a maximum body diameter of 130 mm and a bottom diameter of 100 mm is blow-molded with a molding cycle of 20 seconds, the lower end of a parison having a constant diameter of 60 mm extruded from the die head is pinched. After closing, the pressure of the parison air is set to 6Kpa from 1st to 5th seconds, and the pressure is 7K from 6th to 8th seconds.
Pa, the pressure is 9 Kpa from 9 to 12 seconds, and 1
From the 3rd to 15th second, the pressure is set to 7 Kpa, and further 16 to
By the time of 20 seconds, the parison is inflated to a diameter of 90 mm by controlling the pressure to inflate the parison by setting the pressure to 6 Kpa and finally to the lower torso and the shoulder. Inflate it to a diameter of 100 mm, and finally inflate the middle part of the body and the portion corresponding to the handle to a maximum diameter of 120 mm.
Furthermore, the part corresponding to the nozzle part is finally 90 mm in diameter.
Can be inflated to.

The shape of the parison supplied into the split mold by the pressure control of the parison air is 1000c.
The parison shape can be adjusted to an optimum shape corresponding to the cavity of the split mold of the hand bottle of c.

The pressure control of the parison air in this blow molding method is performed, for example, by combining a pressure regulating valve provided in the parison air supply system and a control device such as a computer for controlling the pressure regulating valve.

According to such a blow molding method, the shape of the parison supplied into the split mold can be adjusted by controlling the pressure of the parison air according to the shape of the product to be blow molded. Can be adjusted to the optimum parison shape corresponding to the cavity.

Therefore, according to such a blow molding method, it is possible to improve the moldability of the nozzle portion and the handle portion, prevent deterioration of ESC property and drop strength, and form a transparent wind stripe. In addition, it is possible to blow-mold a product that does not break in the middle and has an excellent appearance.

Further, in this blow molding method, since the parison having a shape corresponding to the cavity can be supplied, the occurrence of burrs can be suppressed, and the handle portion and the nozzle portion can be formed in the handle bottle molding. Blow molding without burr is also possible.

Furthermore, since the parison extruded from the die head can be made small (thin), the equipment can be made compact.

[0032]

EXAMPLES Examples of the blow molding method of the present invention will be described below together with comparative examples, but the present application is not limited to these examples.

(Example) The maximum body diameter is 90 mm and the bottom diameter is 7
In order to blow mold a 0 mm 720 cc handle bottle with a molding cycle of 14 seconds, after pinching the lower end of the parison with a diameter of 60 mm extruded from the die head,
From 1 to 3 seconds, the pressure of parison air is 3 Kpa, 4 to 4
5Kpa until the 9th second, 2Kpa until the 10th-14th seconds
The handle bottle was blow-molded by adjusting to a pin-shaped parison shape having a bowling shape suitable for molding.

The obtained handle bottles were evaluated for the four items of appearance, ESC property test, drop test and burr rate based on the specific evaluation methods shown in Table 1.

The results of these evaluation methods are shown in Table 2.
It was shown to.

As is clear from the table, the external appearance was good with no protrusion of bottom pinch-off and no breakage of the vidicon. In the ESC property test and the drop test, there was no damage at all and the burr ratio was It was 23% and could be reduced as compared with the conventional one.

(Comparative Example) The same handle bottle as in Example was blow-molded using a cylindrical parison with a diameter of 60 mm, and the obtained handle bottle was evaluated for the same four items as in Example and the results are shown in a table. Shown in 2.

All the evaluation items were inferior to those of the examples, and the burr rate was a large value of 29%.

[0039]

[Table 1]

[0040]

[Table 2]

Next, in a blow molding device for a hollow container to which such a blow molding method is applied, two split molds are arranged in two mold rows shown in FIGS. As an example, a case will be described in which blow molds are performed by combining moving split molds of four stages A, B, C, and D in two moving directions x and y orthogonal to each other.

2 to 5 relate to an example of a blow molding apparatus, FIG. 2 is a schematic perspective view, FIG. 3 is a partial plan view, FIG. 4 is a partial side view, and FIG. 5 is a part of a mold opening / closing mechanism of a split mold. It is a top view.

The blow molding device (hereinafter, simply referred to as a blow molding device) 10 for this hollow container is provided with a pedestal 11 installed on a foundation, and a die head E for supplying a parison is sandwiched on the pedestal 11. Then, two LM guides 12 and 13 are mounted on both sides in parallel in the y direction,
Y-direction moving bases 14 and 15 are provided so as to be capable of reciprocating along the LM guides 12 and 13, respectively.

As shown in FIG. 4, these y-direction moving bases 14 and 15 have a welded box type structure and have a box-shaped outer shape.
It is constructed by arranging reinforcing materials inside and welding them to reduce weight.

Then, in each of the y-direction moving bases 14 and 15,
As shown in FIGS. 3 and 4, a ball nut 17 screwed into a ball screw 16 disposed between the LM guides 12 and 13 is fixed to the bottom portion, and a gear mechanism 18 attached to an end portion of the ball screw 16 is used. By rotating the ball screw 16 with the servo motor 19, the y-direction moving table 1
4, 4 and 15 can be moved in parallel with the die head E.

On these two y-direction moving bases 14 and 15, two sets of LM guides 20 and 2 along the x-direction orthogonal to the y-direction approaching and separating from the die head E are provided.
Two 1,2,23 are installed in parallel, and each LM
Along the guides 20-23, the x-direction moving table 24, 25, 2
6, 27 are provided so as to be capable of reciprocating, and two x-direction moving bases are provided for each y-direction moving base.

As shown in FIG. 4, these x-direction moving bases 24 to 27 also have a welded box type structure and have a box-shaped outer shape.
It is constructed by arranging reinforcing materials inside and welding them to reduce weight.

As shown in FIGS. 3 and 4, a ball nut 29 screwed into a ball screw 28 arranged between the LM guides 20 to 23 is fixed to the bottom of each of the x-direction moving bases 24 to 27. By rotating the ball screw 28 by the servo motor 31 via the gear mechanism 30 attached to the end of the ball screw 28, each x-direction moving table 24 can be moved.
˜27 can be moved in the x direction to approach / separate from the die head E.

With the combination of the y-direction moving bases 14 and 15 and the x-direction moving bases 24 to 27, the respective x-direction moving bases 24 to 27 move toward and away from the die head E (reciprocating movement in the x direction). Or move in parallel (reciprocating movement in y direction)
can do.

The same mechanism is mounted on each of the x-direction moving bases 24 to 27 to configure each of the stages A to D. Here, the A stage of the x-direction moving base 24 will be described as an example. In the other stages B to D, the same symbols are given to the same parts, and the description thereof will be omitted.

On the moving table 24 in the x direction, two LM guides 32 are provided along the y direction, and a pair of mold supporting bases 3 are provided.
3 are provided so as to face each other and can be opened and closed, and a pair of split molds 34, 34a are provided on the facing surfaces of the pair of mold support bases 33, 33a.
Are attached and the cavities face each other. And
Since the pair of split molds 34 and 34a are opened and closed to close the mold, one end of the link 36 that constitutes the link mechanism 35 is attached to the mold support 33 located on the outer side in the y direction of the gantry 11. Link 37 connected to this link 36
The other end of the split mold 34 is rotatably supported by the support base 38, and is rotationally driven by the servomotor 40 via the gear mechanism 39, so that one split mold 34 is opened and closed.

The other split mold 3 facing the split mold 34.
As shown in FIG. 5, 4a is a mold support base 3 of the split mold 34.
While attaching the rack 41 along the opening and closing direction to 3,
A rack 41a along the opening / closing direction is attached to the die support table 33a of the split die 34a via a connecting rod 42 and a buffer spring 43 so as to face the rack 41, and the x-direction moving table 24 is provided with these two racks 41, 41a. A pinion 44 that meshes with each other is attached, and the split mold 34a is moved closer to the split mold 34 driven by the servo motor 40.
The split molds 34, 34a are opened and closed.

Then, in a state where the driving-side split mold 34 is closed, the two links 36 and 37 are aligned so that the mold closing positions of the split molds 34 and 34a are determined.
The pair of split molds 34, 34a are brought into a connected state by locking respective mold closing arms (not shown), and the split mold 3
The pressure cylinder 45 provided at the back of 4a can apply a mold closing force to the mold closing state, while the buffer spring 43 does not affect the racks 41, 41a and the pinion 44 by the buffer spring 43.

Further, each of the y-direction moving bases 14 and 15 has two
The blow mechanism 46 for blowing air into the parison in the split molds 34, 34a closed on the two x-direction moving bases 24, 26 and 25, 27 and for cooling the bulged intermediate molded product from the inside is provided. They are provided one by one, and are provided via an L-shaped blow mechanism support base 47.

The L-shaped blow mechanism support 47 has
A frame 48 is provided so as to be adjustable in position by moving in the x direction, a blow pin 49 is attached so as to be able to move up and down along the frame 48, and is positioned and connected / opened on the split molds 34, 34a in the mold closed state. Is done.

The frame 48 is provided with two LM guides (not shown) in the vertical direction and a slide block 50 which is moved up and down by a ball screw, and the slide block 50 is further moved up and down by two LM guides and a ball screw. A blow table 51 is provided and a blow pin 49 is attached so as to be able to move up and down. The blow pin 49 is connected to and released from the split molds 34 and 34a, and the blow pin 49 is inserted into and removed from a bulged intermediate molded product. By using a double lifting mechanism, the total height is lowered.

On the outside of the gantry 11 in the x direction of the die head E, there are provided product take-out devices T, respectively.

Further, the movement of the y-direction moving table and the movement of the x-direction moving table are controlled by a control device such as a computer which constitutes a movement control means (not shown), and the opening and closing of the split mold, the raising and lowering of the blow pin and the air movement. Supply is controlled by a control device such as a computer.

Next, the operation of the blow molding apparatus 10 having the above-described structure and the blow molding of the hollow container will be described with reference to the process explanatory diagrams of FIGS. In this blow molding method, of the four stages A, B, C and D, the stage A and the stage C are arranged adjacent to each other in the y direction to form one mold row, and the die head E is sandwiched between the stage A and the stage C to form the stage B. Blow molding is performed in the order of the stages A, B, C, and D, with the stage D arranged adjacently to form the other mold row.

First, the two y-direction moving bases 14 and 15 are set to L.
By moving along the M guides 12 and 13, the stage A and the stage B move to a position facing the die head E, which is a position (left end position in the drawing) facing the parinson receiving position (see FIG. 6A). .

After this, the split molds 34, 34a of the stage A are
Is opened by the servomotor 40, the gear mechanism 39, the link mechanism 35 and the rack 41, the pinion 44, and the rack 41a, and the x-direction moving table 24 is moved along the LM guide 20 to the parison receiving position directly below the die head E, The parison whose parison shape has been adjusted as described above is received (see FIG. 6 (a)), and the servo motor 4 is operated in the opposite manner to the mold opening.
0 closes the mold.

Next, the split molds 34, 34a of the stage A which received the parison are returned to the blow molding position which is the position separated from the original die head E along the LM guide 20 by the movement of the x-direction moving table 24. At the same time, the blow mechanism 46 connects the blow pin 49 to the split molds 34, 34a by lowering the slide block 50 to blow air and inflate it, and then lowers the blow table 51 to inflate the blow pin 49 inside the intermediate molded product. Blow-molding and cooling by blowing air.

Simultaneously with the retreat of the x-direction movable table 24 of the stage A, the x-direction movable table 25 is moved to the LM guide 21 in a state where the die dies E are sandwiched between the opposing mold halves 34 and 34a of the stage B. Along the die head E, the parison is moved to the parison receiving position, receives the parison adjusted to the parison shape described above (see FIG. 6B), and the servo motor 40 closes the mold, contrary to the mold opening.

Next, the split molds 34, 34a of the stage B which received the parison are returned to the blow molding position which is the position separated from the original die head E along the LM guide 21 by the movement of the x-direction moving table 25. At the same time, the blow mechanism 46 connects the blow pin 49 to the split molds 34, 34a by lowering the slide block 50 to blow air and inflate it, and then lowers the blow table 51 to inflate the blow pin 49 inside the intermediate molded product. Blow-molding and cooling by blowing air.

On the other hand, the stage C is moved in the y direction on the moving table 14 in the y direction.
The position facing the parison receiving position (the right end position in the drawing) facing the die head E by the movement in the direction (FIG. 7).
(See (a)). The movement in the y direction so as to oppose the parison receiving position of the stage C is performed regardless of the operation of the stage B after the x-direction moving table 24 of the stage A is retracted.

Simultaneously with the retreat of the x-direction movable table 25 of the stage B, the x-direction movable table 26 is moved with the die dies 34, 34a of the stage C located opposite to each other with the die head E sandwiched therebetween. It moves to the parison receiving position just below the die head E along the LM guide 22, and receives the parison adjusted to the parison shape described above (see FIG. 7).
(See (b)), and the mold is closed by the servomotor 40 contrary to the mold opening.

Next, the split molds 34 and 34a of the stage C which received the parison are returned to the blow molding position which is the position separated from the original die head E along the LM guide 22 by the movement of the x-direction moving table 26. At the same time, the blow mechanism 46 connects the blow pin 49 to the split molds 34, 34a by lowering the slide block 50 to blow air and inflate it, and then lowers the blow table 51 to inflate the blow pin 49 inside the intermediate molded product. Blow-molding and cooling by blowing air.

On the other hand, the stage D is moved in the y direction on the moving table 15 in the y direction.
The position facing the parison receiving position (the right end position in the drawing) facing the die head E by the movement in the direction (FIG. 7).
(See (b)). The movement in the y direction so as to face the parison receiving position of the stage D is performed regardless of the operation of the stage C after the backward movement of the x-direction moving table 25 of the stage B.

Simultaneously with the retreat of the x-direction movable table 26 of the stage C, the x-direction movable table 27 is moved with the die dies 34, 34a of the stage D, which are opposite to each other with the die head E sandwiched therebetween. It moves to the parison receiving position directly below the die head E along the LM guide 23, and receives the parison adjusted to the parison shape described above (see FIG. 7).
(See (b)), and the mold is closed by the servomotor 40 contrary to the mold opening.

Next, the split molds 34, 34a of the stage D which received the parison are returned to the blow molding position which is the position separated from the original die head E along the LM guide 23 by the movement of the x-direction moving table 27. At the same time, the blow mechanism 46 connects the blow pin 49 to the split molds 34, 34a by lowering the slide block 50 to blow air and inflate it, and then lowers the blow table 51 to inflate the blow pin 49 inside the intermediate molded product. Blow-molding and cooling by blowing air.

On the other hand, the stage A is moved in the y direction on the moving table 14 in the y direction.
A position facing the die head E, which is a position (left end position in the drawing) facing the parison receiving position when moved in the direction (see FIG. 8).
(See (a)). Then, the mold halves 34, 34a of the stage A, which are positioned to face each other with the die head E interposed therebetween,
The mold is opened, and the product is taken out by the product take-out device T installed behind it. The product is taken out by moving in the y direction so as to face the parison receiving position of the stage A, regardless of the operations of the stages B and D after the retreat of the x direction moving table 26 of the stage C.

Next, at the same time when the x-direction moving table 27 of the stage D is retracted, the stage A is in a position where the die head E is sandwiched and the product is taken out and the split molds 34 and 34a are opened. , LM the x-direction moving table 24 again
It moves to the parison receiving position directly below the die head E along the guide 20, receives the parison adjusted to the parison shape described above (see FIG. 8B), and closes the mold with the servo motor 40 contrary to the mold opening. To do.

By the stage of receiving the parison of the stage A, the stage B is moved to the position corresponding to the die head E, which is the position (left end position in the drawing) facing the parison receiving position by the movement of the y-direction moving table 15 in the y direction. (See FIG. 8B), the split molds 34, 34a of the stage B are opened, and the product take-out device T installed behind the split molds 34, 34a
Take out the product. The product is taken out by moving in the y direction so as to face the parison receiving position of the stage B, regardless of the operations of the stages A and C after the retreat of the x direction moving table 27 of the stage D.

After that, the blow molding is continuously carried out by repeating the movement in the y direction to the position facing the parison receiving position, discharging the product, and receiving the parison again at the parison receiving position.

According to such a blow molding apparatus 10,
Two split molds 34, 3 consisting of stage A and stage C
4a, one mold row and two split molds 34, 34a composed of the stage B and the stage D, the other mold row being moved in the y direction, and each split mold 34, Three
Since blow molding is performed in combination with the movement in the x direction of 4a, blow molding can be continuously performed with four split molds, and the number of molds can be reduced as compared with the case of using a rotary blow molding device. It is possible to greatly reduce the number of molds, which can be exchanged in a short time, and the cost of manufacturing molds can be reduced. In this case, it is possible to easily perform blow molding with only one stage or blow molding with only two stages.

Further, according to this blow molding apparatus 10,
One die head E and four-stage split molds 34, 34a
Since blow molding can be performed with, the parison can be supplied in a stable state, and the molding efficiency can be greatly improved compared to the conventional shuttle type blow molding device, and mass production can be supported. .

On the other hand, by forming a multi-parison for supplying a plurality of parisons and forming a plurality of cavities corresponding to each split mold to form a multi-mold, it is possible to further improve the molding efficiency, or It is also possible to improve the molding efficiency by increasing the number of stages provided in the mold row and increasing the molds, and it is possible to easily make a configuration corresponding to the production amount such as a combination thereof.

Further, according to the blow molding apparatus 10, after the parison is received by each split mold 34, 34a,
The time from taking out a product to receiving the next parison can be lengthened without being restricted as in the case of the rotary blow molding machine, and the product can be taken out with a margin and blow. It is possible to mount the label in the split mold for mounting the label at the time of molding with a margin.

Further, since the y-direction moving bases 14 and 15 and the x-direction moving bases 24 to 27 have the welding box type structure, the weight can be reduced, the driving force required for the movement can be reduced, and the size can be reduced. It is also possible to drive with the servo motor, and it is possible to perform positioning with high accuracy.

In this case, the moving directions of the split molds are the x and y directions which are orthogonal to each other, but the invention is not limited to this, and the split molds may be moved in two directions such as the x direction and the direction intersecting with this. . In addition, the parison can be supplied not only in the case of a single parison but also as a parti parison. In the case of a single parison, a stable parison can be easily obtained, and in the case of a multi parison, blow molding efficiency can be improved. Can be greatly improved.

Furthermore, the number of installed split molds is not limited to four, but may be increased. In the blow molding method, the number of split molds used for molding may be reduced to perform blow molding. it can.

[0082]

As described above in detail with the embodiment, according to the blow molding method for a hollow container according to claim 1 of the present invention, the bottom of the parison supplied to the split mold is pinched. After that, the parison air supplied to the inside of the parison was controlled to adjust the pre-blow shape to be delivered to the split mold, so instead of the parison with a constant diameter, the parison with the adjusted pre-blow shape was used as the split mold. By delivering the hollow container, the hollow container can be blow-molded efficiently while suppressing the deterioration of strength while ensuring the moldability.

According to the blow molding method of the hollow container according to the second aspect of the present invention, since the control of the parison air is controlled by the pressure of the parison air, the diameter of the parison extruded from the die head can be simplified. It can be changed, and a necessary portion can be enlarged (thickened) to form a pre-blow shape having excellent moldability.

Further, according to the blow molding method for a hollow container according to claim 3 of the present invention, the pre-blow shape of the parison is adjusted to a shape corresponding to the cavity shape of the split mold, so that the moldability is improved. It is possible to further improve the quality, and it is possible to eliminate wasteful parison and minimize the occurrence of burrs.

Therefore, according to the blow molding method of these hollow containers, the moldability of the nozzle portion and the handle portion can be improved, the ESC property and the drop strength can be prevented from being lowered, and a transparent wind stripe is formed. In this case, a product having an excellent appearance can be blow-molded without breaking in the middle.

Further, according to these blow molding methods, since the parison having the corresponding shape can be supplied to the cavity, it is possible to suppress the generation of burrs, and to make the parison shape free from burrs. Can also
This enables blow molding without any burrs.

Further, since the parison extruded from the die head can be made small (thin), the equipment can be miniaturized.

[Brief description of drawings]

FIG. 1 is a process explanatory view schematically showing a relationship between a cavity of a split mold and a parison according to an embodiment of a blow molding method for a hollow container of the present invention.

FIG. 2 is a schematic perspective view of an example of a blow molding apparatus to which the blow molding method of the present invention is applied.

FIG. 3 is a partial plan view of an example of a blow molding apparatus to which the blow molding method of the present invention is applied.

FIG. 4 is a partial side view of an example of a blow molding device to which the blow molding method of the present invention is applied.

FIG. 5 is a partial plan view of a mold opening / closing mechanism of a split mold of an example of a blow molding apparatus to which the blow molding method of the present invention is applied.

FIG. 6 is a process explanatory view of first and second steps of an example of a blow molding apparatus to which the blow molding method of the present invention is applied.

FIG. 7 is a process explanatory view of third and fourth steps of an example of a blow molding apparatus to which the blow molding method of the present invention is applied.

FIG. 8 is a process explanatory view of fifth and sixth steps of an example of a blow molding apparatus to which the blow molding method of the present invention is applied.

FIG. 9 is an explanatory sectional view schematically showing a relationship between a cavity of a conventional split mold and a parison.

[Explanation of symbols]

1 split mold 2 cavities 2a nozzle part 2b handle 2c shoulder 2d body 2e bottom 3 parison 3a Pinch part 3b upper end 3c middle part 3d lower end 4 die head Extrusion length of L parison 10 Blow molding equipment 11 stand 12, 13 LM guide 14, 15 y direction moving stand 16,28 Ball screw 17,29 Ball nut 18,30 Gear mechanism 19,31 Servo motor 20, 21, 22, 23 LM guide 24, 25, 26, 27 x direction moving stand 32 LM Guide 33,33a die support 34, 34a Split mold 35 Link mechanism 36,37 links 38 Support 39 gear mechanism 40 servo motor 41, 41a rack 42 Connecting rod 43 Buffer spring 44 pinion 45 pressure cylinder 46 Blow mechanism 47 Blow mechanism support 48 frames 49 Blow Pin 50 slide blocks 51 blow stand A, B, C, D stages E Die head (Parison pick-up position) T product removal device

Claims (3)

[Claims] 1. A blow molding method for a hollow container, wherein a split mold is moved to a parison receiving position where a parison is supplied to receive the parison, and the mold is closed and blow molded at a blow molding position. A blow molding method for a hollow container, characterized in that after the bottom of the parison supplied to the mold is pinched, the parison air supplied to the inside of the parison is controlled to adjust the pre-blow shape to be delivered to the split mold. 2. The blow molding method for a hollow container according to claim 1, wherein the control of the parison air is performed by controlling the pressure of the parison air. 3. The blow molding method for a hollow container according to claim 1, wherein the pre-blow shape of the parison is adjusted to a shape corresponding to the cavity shape of the split mold.