JPH09254238A - Method for blow molding and blow molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate an upper burr from a die and to prevent foreign matters from falling down by taking out a product by moving a parison in the product taking-out direction after the parison is once lowered when taking out of the product is started after molding. SOLUTION: An upper pinching device 10 is provided with a pair of left and right pinch bars 10a being brought into contact with and separated in the mold opening and closing direction and this is connected with a piston rod 12a of an opening and closing cylinder 12 through a links 11a and 11b and opening and closing are performed by forwarding and retreating of the piston rod 12a. In addition, the opening and closing cylinder 12 is elevated and lowered by means of two standing elevating and lowering cylinders 13 and is horizontally freely movable in the direction intersecting at right angles to the mold opening and closing direction by means of a horizontal cylinder 14. In addition, by lowering once the whole apparatus by means of the elevating and lowering cylinder 13 and moving it in the mold opening and closing direction by means of the horizontal direction 14, a product is separated from an extruded parison and is taken out. As the result, there exists no possibility of rubbing the underside of a die with the upper burr and staining the surface of a cavity with deteriorated substances of the underside of the die.

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 a blow molding machine for molding a parison ejecting a molten resin with a pair of right and left molds to obtain a resin molded product, and particularly when taking out a product after molding. The blow molding method and blow molding are designed to prevent the mold cavity surface from being contaminated by rubbing the lower surface of the die with the upper surface of the parison that has been cut and separated, and removing the deteriorated materials and dust that adhere to the lower surface of the die. Regarding the machine.

[0002]

2. Description of the Related Art In blow molding for producing a hollow resin product from a parison injected or extruded into a cylindrical shape from a die head, a parison is injected or extruded from a die head, and a pre-blow is applied to a parison formed into a bag by a parison pinch. Line, inflate it slightly, put it in an open mold, close the mold, evacuate the gas in the cavity formed by the mold and the parison, and then vacuum pump the device through a small air vent hole to the mold surface Then, high-pressure air is blown into the parison to form the parison into a predetermined shape based on the cavity, and the parison is cooled with a mold to complete the molding. In this way, the molded resin product is opened and taken out.

FIG. 9 shows a conventional blow molding machine. In FIG. 9, the molten resin is applied to the side 1 of the die head 2.
A so-called side-feed type blow molding machine 1 supplied from a point is shown, in which a high-temperature molten resin pressed by an injection device 4 is provided between a die head 2 and a mandrel 3 via a resin supply port 2a. Through a circular passage
The parison P is formed by being discharged from the lowermost annular space passage 7. The core 3a is connected to the paricon rod 6a penetrating the mandrel 3 and is slightly moved up and down in the vertical direction by the operation of the paricon cylinder 6 to control the wall thickness of the parison P (gap). )
Can be adjusted.

On the other hand, in such a blow molding machine 1, as shown in FIG. 9, a pair of left and right upper pinch devices 10 are arranged between the die head 2 and the die 8, and the parison immediately after the start of discharge. The lower end of P is tightly connected. In the conventional upper pinch device, the parison is tightly connected by two scissor-shaped bars, or by two adjacent bars in parallel. And, in many cases, the product after pre-blowing by sandwiching the parison with a mold,
By using the upper pinch device as it is, the parison is divided by horizontally moving horizontally in a pinch state, and the product is taken out.

[0005]

However, when a product is taken out by using the upper pinch device 10 in such a conventional blow molding machine 1, the separated upper burr slides on the lower surface of the die 2. Therefore, the deteriorated materials attached to the lower surface of the die, the peeled molten resin, dust, etc. fall off, and these fall and adhere to the mold cavity surface, and they appear as foreign matter defects on the surface of the molded product at the next molding, It was supposed to impair the quality of the molded product.

[0006]

In order to solve the above problems, in the present invention, in the first invention, a pair of left and right upper pinch devices is provided between the die head and the pair of left and right dies. Provided, in a blow molding machine for blow molding by sandwiching the parison discharged from the annular resin passage between the die head and the core attached to the lower end of the mandrel with a pair of left and right molds, when taking out the product after molding, At the start of taking out, the parison was once lowered, and then the parison was moved in the product taking-out direction to take out the product. According to a second aspect of the present invention, an injection device, a die device that discharges the molten resin supplied by the injection device from the lower end as a parison, and a pair of left and right mold devices that perform blow molding with the parison interposed therebetween are provided. In a blow molding machine equipped with an upper pinch device between the device and the mold device, the upper pinch device includes a pair of left and right pinch portions that pinch the side surface of the parison in the mold opening / closing direction, and When the product is taken out, the pinch portion is once lowered in the vertical direction and then horizontally moved in a direction orthogonal to the mold opening / closing direction. Further, in the third invention,
An injection device, a die device that discharges the molten resin supplied by the injection device from the lower end as a parison, and a pair of left and right mold devices that perform blow molding while sandwiching the parison,
In a blow molding machine equipped with an upper pinch device between the die device and the mold device, a pair of left and right holding portions for holding the parison and the holding portion when taking out the product, directly above or directly below the upper pinching device. The product take-out device is composed of a product take-out section having a product take-out function of moving the section once in the vertical direction and then moving it in a direction orthogonal to the mold opening / closing direction. Further, in the fourth invention, the product take-out function of moving the pinch portion or the sandwiching portion once in the vertical direction and then moving it in a direction orthogonal to the mold opening / closing direction is provided with a vertically moving fluid pressure cylinder and a horizontal direction. It was carried out in combination with a moving hydraulic cylinder. Also,
In the fifth invention, the product take-out function of temporarily lowering the pinch part or the sandwiching part in the vertical direction and then moving it in the direction orthogonal to the mold opening / closing direction is provided with a urging force that hangs down due to the weight of the parison when gripping the parison. It is carried out by the combination of the deformation of the spring having the above and the horizontal movement by the fluid pressure cylinder or the motor driven rack and the pinion. Then, in the sixth invention, the product take-out function of moving the pinch portion or the holding portion once in the vertical direction and then moving it in the direction orthogonal to the mold opening / closing direction is provided with a vertical or descending inclined portion and a horizontal lateral movement portion. In the seventh invention, the cam follower is guided and moved in a guide groove connected to and, and in the seventh aspect of the invention, a vertical vertical worm shaft or a ball screw mechanism is used for descending and a horizontal hydraulic cylinder or a motor-driven rack and pinion. This is carried out in combination with the lateral movement by

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the method of the present invention, a pair of left and right upper pinch devices are provided between a die head and a pair of left and right dies, and a ring between the die head and a core attached to the lower end of a mandrel. In a blow molding machine that blow-molds a parison discharged from the resin passage with a pair of left and right dies, when the product after molding is taken out, the parison is temporarily lowered at the start of taking out and then the parison is moved in the product taking-out direction. Since the upper burr that has been separated does not rub the lower surface of the die when removing the product, it is possible to remove deteriorated materials, molten resin, dust, etc. adhering to the lower surface of the die from the lower surface of the die. Does not contaminate the mold cavity surface. The blow molding machine of the second invention is
The upper pinch device is made to have such a take-out function and is automatically executed. The blow molding machine of the third invention is provided with a product take-out device having such a function as the upper pinch device. The configuration was prepared separately in the latest. Also, the fourth
The blow molding machine according to the seventh aspect of the invention embodies a product take-out function of moving the pinch part or the sandwiching part once in the vertical direction and then moving it in the direction orthogonal to the mold opening / closing direction. The vertical fluid pressure cylinder and horizontal fluid pressure cylinder are used in combination, the spring and horizontal fluid pressure cylinder are used in combination, and the cam follower is guided in a substantially L-shaped guide groove. By using a worm rotating shaft or a ball screw mechanism, deterioration products, molten resin, dust, etc. adhering to the bottom surface of the die are removed from the bottom surface of the die and the mold cavity surface is not contaminated. Can be taken out.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 8 relate to an embodiment of the present invention, FIG. 1 is an overall vertical sectional view of a blow molding machine, FIG. 2 is a plan view taken along line AA of FIG. 1, and FIG. 3 is taken along line BB of FIG. FIG. 4 is a schematic side view of the upper pinch device (before the pinch) showing another embodiment.
5 is a schematic side view of the upper pinch device of FIG. 4 (after pinch)
6 is a schematic side view of an upper pinch device showing another embodiment, FIG. 7 is a schematic side view of an upper pinch device showing yet another embodiment, and FIG. It is a top view of an upper pinch device.

1 to 3 show a blow molding machine 100 showing a first embodiment of the present invention. 1 to 3, a pair of left and right molds 8, 8 is disposed below the die head 2 of the blow molding machine 100 so as to be freely contactable and separable, and the mold 8 is
In the portion facing the cavity surface of, a medium passage (not shown) for switching and flowing a heat medium or a refrigerant body as needed to heat or cool the cavity surface of the molds 8, 8 is provided.
It is connected to a medium (heat medium or coolant) switching supply device (not shown). Immediately below the die head 2, there is provided an upper pinch device 10 including a pair of left and right pinch bars 10a that horizontally contact and separate in the same direction as the mold opening and closing direction. The pinch bar 10a is composed of two bars that open and close like scissors, or two bars that are brought into contact with and separated from each other by a horizontal cylinder.

In the first embodiment of the present invention, as shown in FIGS. 2 and 3, the upper pinch device 10 is provided with a pinch portion provided with two pinch bars 10a which come in contact with and separate from each other in the mold opening / closing direction. The pinch device 10 is provided with a product take-out function of temporarily lowering the pinch part in the vertical direction when taking out the product after molding the parison and then horizontally moving it in a direction orthogonal to the mold opening / closing direction. is there. That is,
The pair of left and right pinch bars 10a includes links 11a and 11b.
It is connected to the piston rod 12a of the open / close cylinder 12 via the, and is opened / closed by the forward / backward movement of the piston rod 12a. As shown in FIG. 3, the opening / closing cylinder 12 is vertically movable by two vertically elevating cylinders 13, and is horizontally moved by a horizontal cylinder 14 in a direction orthogonal to the mold opening / closing direction. It can be moved freely.

On the other hand, FIG. 4 and FIG. 5 show an upper pinch device 10A of the second embodiment of the present invention, in which a mechanism for temporarily lowering it at the time of taking out a product uses the parison's own weight after the pinch, and a pinch bar. The link 15 is pin-joined to the end of 10a, and the tension coil spring 15a is attached to one end of the link 15.
And the parison P is pinched from the pre-pinch state of FIG. 4 and then loaded on the pinch bar 10a.
The entire upper pinch device 10A hangs down against the urging force of the tension coil spring 15a by its own weight.
The downward limit is the position where the link 15 contacts the stopper 15b.

FIG. 6 shows an upper pinch device 10B according to a third embodiment of the present invention, in which a cam follower 17 that rotates around a horizontal axis at the edge of the upper pinch device 10B is provided.
The cam follower 17 is formed in an L shape, or as shown in FIG.
It is designed to be rolled inside 8.

7 and 8 show an upper pinch device 10C according to a fourth embodiment of the present invention, in which the lowering operation of the pinch part is performed by the worm shaft 19a rotated by the motor 19 and the worm shaft 19a. The nuts meshed with the driven vertical worm shaft 19b are used to move up and down in conjunction with each other. In such a rotary system, a ball screw mechanism can be adopted in a similar manner.

The upper pinch device 1 configured as described above
The operation of the blow molding machine 100 having 0 or the upper pinch devices 10A, 10B, and 10C will be described. With the molds 8, 8 opened, the injection device 4 is operated to transfer the molten resin to the annular space passage 7 between the die head 2 and the core 3a.
After discharging a little more and stopping in a hanging state, operating the pair of left and right pinch bars 10a of the upper pinch device 10 to tightly connect the lower end of the parison P (referred to as pre-pinch), and then opening the pinch bar 10a to discharge the parison again. Continue,
After passing between the two molds 8 which have been opened, the parison is stopped again when the lower end of the parison reaches below the mold 8 (Fig. 1).
State). Then, after closing both dies 8 and 8, a blow pin (not shown) is inserted into the parison P for blowing to improve transferability of the die cavity surface to the parison surface, and then a constant cooling time. After the lapse of time, the upper pinch device 10 is driven again to pinch the upper end of the parison P, and then the dies 8 are opened to take out the product.

In the case of the present invention, this product take-out is characterized in that in the upper pinch device 10, the lifting cylinder 13 temporarily lowers it, and then the horizontal cylinder 14 moves the entire device in a direction perpendicular to the mold opening / closing direction. By retracting (retracting to the front side in FIG. 1), the product is separated from the discharged parison P and the product is taken out. In the upper pinch device 10A of the second embodiment, after the pinch operation of the pinch bar 10a, the weight of the product is applied to the pinch part when the mold is closed, so that the pinch part is somewhat resisted against the biasing force of the tension coil spring 15a. Since it hangs down, the product is taken out by retracting it from the mold part by a horizontal cylinder (not shown). In the upper pinch device 10B of the third embodiment, the cam follower 17 is rolled into the groove 18 so that the cam follower 17 hangs down and then moves horizontally. Furthermore, in the upper pinch device 10C of the fourth embodiment,
The product is taken out by moving the device by combining the downward movement and horizontal movement of the nut that meshes with the rotation of the worm shaft 19b, or by the downward movement and horizontal movement of the ball screw mechanism.

As described above, in the blow molding machine 100 of the present invention, the upper pinch device 10, or 10A, 10A.
In B and 10C, the product is taken out by moving the upper pinch device at the time of product taking-out, after lowering it once and then moving it horizontally. Does not rub the bottom surface of the die 2. Therefore, it becomes possible to automatically take out the respective products without causing deterioration products, molten resin, dust, etc. adhering to the lower surface of the die to drop from the lower surface of the die to contaminate the mold cavity surface.

[0017]

As described above, in the present invention,
When the product is taken out, the upper pinch device is moved so that the product is taken out by lowering it once and then moving horizontally.
The following excellent effects can be exhibited. The burr on the product is completely separated from the die. The upper burr does not slide on the lower surface of the die, foreign matter is prevented from falling, and adhesion to the mold cavity and contamination are reduced. Molding defects due to foreign matter are reduced, and the quality of molded products is improved.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view of a blow molding machine according to an embodiment of the present invention.

FIG. 2 is a plan view taken along the line AA of FIG.

FIG. 3 is a schematic side view taken along the line BB of FIG.

FIG. 4 is a schematic side view of an upper pinch device (before pinch) according to another embodiment of the present invention.

5 is a schematic side view of the upper pinch device (after pinch) of FIG. 4. FIG.

FIG. 6 is a schematic side view of an upper pinch device according to another embodiment of the present invention.

FIG. 7 is a schematic side view of an upper pinch device showing still another embodiment of the present invention.

8 is a plan view of the upper pinch device of FIG. 7. FIG.

FIG. 9 is an overall vertical sectional view of a conventional blow molding machine.

[Explanation of symbols]

 1 Blow Molding Machine 2 Die Head (Die) 2a Resin Supply Port 3 Mandrel 3a Core 4 Injection Device 6 Paricon Cylinder 6a Paricon Rod 7 Annular Space Passage 8 Mold 10 Upper Pinch Device (First Embodiment) 10A Upper Pinch Device ( Second embodiment) 10B Upper pinch device (third embodiment) 10C Upper pinch device (fourth embodiment) 10a Pinch bar 11a, 11b Link 12 Open / close cylinder 13 Elevating cylinder 14 Horizontal cylinder 15 Link 15a Extension coil spring 15b Stopper 17 Cam follower 18 groove 19 motor 19a worm shaft 19b worm shaft 100 blow molding machine P parison

Claims (7)

[Claims] 1. A parison discharged from an annular resin passage between a die head and a core attached to a lower end of a mandrel is provided with a pair of left and right upper pinch devices between a die head and a pair of left and right dies. In a blow molding machine that performs blow molding with a pair of left and right molds, when taking out the product after molding, the parison is temporarily lowered at the start of taking out and then the parison is moved in the product take-out direction to take out the product. Blow molding method. 2. An injection device, a die device for discharging the molten resin supplied by the injection device from the lower end as a parison, and a pair of left and right mold devices for blow molding sandwiching the parison, the die device and the die device. In a blow molding machine equipped with an upper pinch device between the mold device and the upper pinch device, the upper pinch device is provided with a pair of left and right pinch portions that pinch the side surface of the parison in the mold opening / closing direction, and when the product is taken out after molding the parison. A blow molding machine provided with a product take-out function of temporarily lowering the pinch portion in the vertical direction and then horizontally moving it in a direction orthogonal to the mold opening / closing direction. 3. An injection device, a die device for discharging the molten resin supplied by the injection device from the lower end as a parison, and a pair of left and right mold devices for blow molding sandwiching the parison, the die device and the die device. In a blow molding machine provided with an upper pinch device between a mold device and a pair of left and right holding parts for holding a parison and a vertical direction when the product is taken out, just above or just below the upper pinch device. A blow molding machine comprising a product take-out device including a product take-out section having a product take-out function of moving the mold once to move it in a direction orthogonal to the mold opening / closing direction. 4. A vertically moving fluid pressure cylinder and a horizontally moving fluid are provided with a product take-out function of temporarily lowering the pinch portion or the holding portion in the vertical direction and then moving the pinch portion or the holding portion in a direction orthogonal to the mold opening / closing direction. The blow molding machine according to claim 2 or 3, which is carried out in combination with a pressure cylinder. 5. The product take-out function of temporarily lowering the pinch part or the sandwiching part in the vertical direction and then moving it in a direction orthogonal to the mold opening / closing direction is provided with a biasing force for hanging the parison by the weight of the parison. The blow molding machine according to claim 2 or 3, wherein the blow molding machine is implemented by a combination of deformation of a spring provided and horizontal fluid pressure cylinder or lateral movement by a rack and a pinion driven by a motor. 6. A vertical or downward sloped portion and a horizontal lateral movement portion are connected to a product take-out function of temporarily lowering the pinch portion or the sandwiching portion in the vertical direction and then moving it in a direction orthogonal to the mold opening / closing direction. The blow molding machine according to claim 2 or 3, wherein the blow molding machine is implemented by a cam follower guided and moved in the guide groove. 7. A product take-out function of temporarily lowering the pinch portion or the holding portion in the vertical direction and then moving the pinch portion or the holding portion in a direction orthogonal to the mold opening / closing direction is provided by a rotatable vertical worm shaft or a ball screw mechanism. The blow molding machine according to claim 2 or 3, wherein the blow molding machine is implemented by a combination of a horizontal hydraulic cylinder or a motor-driven rack and lateral movement by a pinion.