JPH0155982B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a blow molding method and a mold apparatus used for molding a blow molded product having a nozzle portion.

[Background technology]

Generally, a container having a nozzle portion is manufactured by blow molding in the following manner. That is, as shown in FIG.
The parison 3 is placed in the cavity 2 of the mold, the parison 3 is inflated by blowing air through the air blowing nozzle 4, and after being cooled, the mold body 1 is opened. In addition, in FIG. 1, 5 is a mold parting line, and 6 is a bottom burr. FIG. 2 shows a nozzle-equipped container manufactured by blow molding in this manner. In FIG. 2, 7 is a container body, and 8 is a nozzle portion provided on the container body 7. In this case, the nozzle part 8 of the container manufactured by blow molding has a burr 6a as shown in FIG. 3 due to the mold parting line 5 (see FIG. 1), and the root part of the burr 6a As shown in FIG. 4, a recess called a sink mark 9 is formed. Therefore, immediately after molding, the third
The burr 6a shown in the figure is cut off with a knife or the like, and the outer periphery is finished using a special jig to completely remove the burr at the parting part. In particular, when adhesion is required for the nozzle part, it is necessary to remove the sink mark 9 as shown in FIG. 4 and finish the outer periphery of the nozzle part 8 into a perfect circle. Therefore, the outer peripheral surface of the nozzle portion 8 is cut in the circumferential direction to reduce the wall thickness, thereby removing the sink mark 9.
That is, when a container with a nozzle is manufactured by blow molding as described above, the inner circumferential surface of the nozzle portion 8 comes into contact with the outer circumferential surface of the air blowing nozzle 4, resulting in high precision and a good surface condition. . However, since burrs 6a and sink marks 9 as shown in FIGS. 3 and 4 are formed on the outer circumferential surface, there is a drawback that post-processing is required to remove them. In addition, in order to remove the sink mark 9 provided on the outer circumference of the nozzle, it is necessary to cut the outer circumferential surface to reduce the wall thickness, so it is necessary to make the nozzle thicker than necessary in advance. There is also the problem that cutting must be performed in post-processing, resulting in increased material loss.

[Purpose of the invention]

This invention aims at eliminating the need for post-processing and reducing loss.

[Disclosure of the invention]

In blow molding a molded product having a nozzle part, this invention consists of a blow molding part of the mold consisting of a cylindrical rotating body split into two parts, and a pin is driven into the parison inserted into this rotating body, and the pin is driven into the parison. By pushing the post-strike core fitted onto the outside into the rotating body, the parison is sufficiently filled, and by rotating the rotating body, the burrs that have entered into the nozzle parting line are cut off. The first gist is the characteristic blow molding method, in which a cylindrical nozzle provided in the blow molding mold body is placed in the middle of the molding space, and when combined, it becomes cylindrical and its inner peripheral surface Becomes the molding surface 2
A split finishing pinion is fitted coaxially with the nozzle forming space and rotatable in the circumferential direction, and the driving pinion is set to a smaller diameter than the diameter of the nozzle forming space so that it can be inserted through the nozzle forming space. A cylindrical rear end whose outer diameter is set to be less than or equal to the diameter of the nozzle forming space. The second aspect of the present invention is a blow molding mold device characterized in that a push core is fitted onto a driving pin so as to be movable back and forth.

Next, the present invention will be explained in detail based on examples.

FIG. 5 is a cross-sectional view of essential parts of an embodiment of the blow molding mold device according to the present invention, and FIG. 6 is A of FIG.
-A' sectional view. In these figures, 10
is the mold body for blow molding, and its nozzle recess 11
A nozzle part nesting mold 12 is arranged in the . A cylindrical nozzle molding space 13 is formed in this nozzle part nesting mold 12, and a recess 14 formed in the middle of the nozzle molding space 13 has a cylindrical nozzle molding space 13.
A halved finishing pinion 15 is fitted coaxially with the nozzle forming space 13. In this case, 2
The split finishing pinion 15 has a cylindrical shape when assembled, and its inner circumferential surface serves as a forming surface. Also, the split finishing pinion 1
Teeth parallel to the axis are formed in the circumferential direction on the outer peripheral surface of 5. A rack 16 having teeth that mesh with teeth formed on the outer circumferential surface of the two-split finishing pinion 15 is inserted into a space extending laterally within the nozzle part nesting mold 12. The movement in this direction causes the halved finishing pinion 15 to rotate in the circumferential direction (see FIG. 6). 17 is a support frame (not shown) on the mold body 10
A driving pin attached through the nozzle molding space 1 is moved forward by the hydraulic pressure of a hydraulic cylinder (not shown) to form the nozzle molding space 1 in the nozzle part nesting mold 12.
3, and then retreats again to leave the space 13. In this case, driving pin 1
7 is set to move on the central axis 18a of the nozzle forming space 13, and its diameter is set to be smaller than the diameter of the nozzle forming space 13 so that it can be inserted into the nozzle forming space 13. has been done. Reference numeral 18 denotes a post-driving core that is fitted around the outer periphery of the driving pin 17, and the end surface 19 at the tip thereof is fitted into the space between the inner peripheral surface of the nozzle forming space 13 and the outer peripheral surface of the driving pin 17. In order to do so, its outer diameter is set to be approximately the same as or slightly smaller than the diameter of the nozzle forming space 13. This post-driving core 18 is also driven by the driving pin 17 by a hydraulic cylinder (not shown).
It is designed to be able to move back and forth along the . 5 and 6, 20 is a parison, 21 is a cavity of the mold body 10, 22 is a nozzle parting line, and 23 is a nozzle burr flow path.

In this configuration, the manufacture of the nozzle-equipped container by blow molding is carried out in two ways. That is, as shown in FIG. 7, after putting the parison 20 into the mold body 10 and closing the mold, the driving pin 17 is inserted.
is advanced from the position shown by the chain line in FIG. 7, and the parison 20 is inserted into the nozzle forming space 13 through the part of the parison 20 that is protruding from the mold body 10. Next, from this state, the post-driving core 18 is advanced as shown in FIG. Position it inside. By inserting the tip end face of the post-strike core 18 into the space 13, the parison 20 pushed by that part is moved from the nozzle parting line 22 to the nozzle part burr flow path 2 shown in FIG.
Pushed out to 3. In this case, strong pressure is applied to the parison 20 by the pressing force of the tip end surface of the post-strike core 18, so that the nozzle portion of the obtained molded product does not suffer from sink marks as in the conventional case. Next, blowing is performed in this state to cool the parison 20 sufficiently, and then the rack 16 is operated reciprocally (see Fig. 6).
The split finishing pinion 15 is rotated back and forth. By the reciprocating rotation of the split finishing pinion 15, the burrs that have entered the nozzle parting section are cut and discharged from the burr passage 23 to the outside. After cutting and removing the burr, the driving pin 17 and the post-driving core 18 are moved back, and then the mold body 1
0 and take out the blow molded product. A blow molded article is produced in this way.

In the above embodiment, the driving pin 17 and the post-driving core 18 are driven by a hydraulic cylinder, but they may be driven by a pneumatic cylinder. Furthermore, although the two-split finishing pinion 15 is designed to be driven back and forth by the rack 16, it may be driven by some other mechanism.

In the above embodiment, the cylindrical rotary body split into two and finished as a part of the nozzle molding part has a pinion structure, but it is not essential that it has a pinion structure. In short, it only needs to be rotatable.

〔Effect of the invention〕

As described above, in the blow molding method and mold device of the present invention, the nozzle molding space is provided in the cylindrical rotating body finished in two parts, and the driving pin inserted through the nozzle molding space is formed on the outer periphery of the nozzle molding space. A cylindrical post-molding core is fitted onto the outside so that it can move back and forth, and the parison into which the pins have been driven is pushed into the molding space by the post-molding core, so strong pressure is applied to the nozzle molding space during molding. The parison will now be pushed in,
As a result, the nozzle portion of the resulting molded product does not suffer from sink marks as in the past. Further, since the burrs generated on the outer circumferential surface of the nozzle part are removed by the rotation of the two-split finishing rotating body (pinion), it is no longer necessary to remove the burrs in the post-process as in the past. That is, according to this blow molding method and mold apparatus, it becomes possible to finish the inner and outer circumferential surfaces of the nozzle part of a molded product during molding, and post-processing of the nozzle part becomes unnecessary. In addition, since sink marks do not occur on the nozzle part as in the past, there is no need to make the wall thickness of the nozzle part thicker by the amount of sink marks in advance and then remove that thickness in post-processing, which reduces loss. It will be possible to reduce the occurrence.
Furthermore, since the parison can be filled in the required portion by the post-shot core, it is possible to form a stable nozzle portion regardless of the direction of the nozzle portion with respect to the injection parison.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional example, Fig. 2 is a perspective view of a blow-molded product obtained by the method, Fig. 3 is an enlarged perspective view of the nozzle part of the molded product, and Fig. 4 is an illustration of the nozzle part. A cross-sectional view, FIG.
The figure is a cross-sectional view taken along the line A-A', and FIGS. 7 and 8 are explanatory views of the operation. DESCRIPTION OF SYMBOLS 10... Blow molding mold device, 12... Nozzle part nesting mold, 13... Space for nozzle molding, 15... Finishing pinion split into two, 16... Rack, 17... Driving pin, 18... Post-molding core, 20... Parison, 21...
Cavity.

Claims (1)

[Scope of Claims] 1. When blow molding a molded product having a nozzle part, the nozzle forming part of the mold is composed of a cylindrical rotating body split into two parts, and a pin is driven into the parison inserted into this rotating body. At the same time, by pushing the post-strike core fitted onto the pin into the rotating body, the parison is sufficiently filled, and by rotating the rotating body, the burrs that have entered the nozzle parting part are cut off. A blow molding method characterized by: 2 In the middle of the cylindrical nozzle forming space provided in the blow molding mold body, there is a two-split finishing pinion, which becomes cylindrical when combined and whose inner peripheral surface becomes the forming surface, for nozzle forming. A driving pin is fitted coaxially with the space and rotatably in the circumferential direction, and has a diameter smaller than the diameter of the nozzle forming space so that it can be inserted through the nozzle forming space. A cylindrical post-driving core, which is movable back and forth while aligned with the central axis of the nozzle forming space, and whose outer diameter is set to be less than or equal to the diameter of the nozzle forming space, is attached to the driving pin. A blow molding mold device characterized by being fitted onto the outside so that it can move freely back and forth. 3. Claim 2, wherein the split finishing pinion is rotationally driven by a rack.
The blow molding mold device described in Section 1.