JPS63191613A - Blow molding of bent product having insert on parting line - Google Patents

Abstract

PURPOSE:Not to form burrs on a parting line, by introducing a parison into the bent mold cavity with air flow which flows in a bent mold cavity and out from an outlet of the mold cavity sealing the apex of the parison, blowing air into the parison and molding it. CONSTITUTION:A pair of split molds 1 and 1 having half faces 2 and 2 of bend mold cavities constituting half faces 3 and 3 of inlets of the mold cavities opening upward on their one ends and half faces 4 and 4 of outlets of the mold cavities on other ends on their split mold faces respectively are used, and these split molds are closed to form an open-and-pass-through-type bent mold cavity having a mold cavity inlet opening upward on its one end and a mold cavity outlet opening on its another end, and a freely removable specific piece-shaped insert members 13 is set on the positions of split faces of the split molds in the bent mold cavity. Then, a parison P whose diameter is smaller than the min. inside diameter of the mold cavity is inserted in the bent mold cavity from the mold cavity inlet and introduced into the bent mold cavity by giving an air flow (the arrow mark) flowing in the bent mold cavity and flowing out from the mold cavity outlet. Then, the apex of the parison is sealed and air is blown into the parison to mold it.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to blow molding of synthetic resin hollow products that are bent in two or three dimensions and have a piece-like insert part on a parting line. Regarding the method.

(Prior art) Conventionally, as a blow molding method for L-shaped, S-shaped, etc. synthetic resin hollow bent products in which piece-shaped insert parts are attached on the dividing line on the outer surface, half of the bent mold cavity is divided into two parts. With the pair of split molds on the surface open, a required piece-shaped insert part is removably attached to the split surface of one of the split molds. First, a piece of a piece with a diameter slightly larger than the maximum left, right, lateral, and middle of the bent half of the mold is attached. A known method is to extrude and lower a thick parison between two split molds, then close the two split molds by sandwiching the parison, and then blow air into the parison to perform blow molding.

However, with this conventional method, a large amount of pars adheres to the parting line of the obtained bent product, and the insert parts are buried in this pars. The drawback was that the removal work required a great deal of effort.

(Problems to be Solved by the Invention) An object of the present invention is to provide a blow molding method for a synthetic resin hollow bent product in which a piece-shaped insert part is attached on a parting line without being buried in the mold.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a bent mold cavity half face having an upwardly opening mold cavity entrance half face at one end and a mold cavity exit half face at the other end, and a divided face. The pair of split molds are closed to form an open bent mold cavity having an upwardly opening mold cavity inlet at one end and a mold cavity outlet at the other end. A predetermined piece-like insert component is removably attached to the position of the split mold dividing surface in the bent mold cavity, and then a parison with a diameter smaller than the minimum inner diameter of the mold cavity is inserted into the bent mold cavity from the entrance of the mold cavity. Along with inserting.

An airflow is applied to the inside of the bent nest from the outlet of the flow shaped nest, and the parison is introduced into the bent nest by the airflow. Next, the tip of the parison is sealed, and air is blown into the parison. It has a structure that involves molding.

The piece-shaped insert component in the present invention may be of various shapes depending on the purpose of the molded product, and may be made of metal, synthetic resin, or various other materials.

The present invention will be described in detail below with reference to the drawings.

(Example) First, a pair of split molds (]), (1) to form a bent nest.
As shown in Figure 1.2, in this example, L-shaped curved nest half surfaces (2), (2) are respectively formed on the dividing surface, and the dyed half surfaces (2), (2) are At one end there is a split mold (1), (1
), which opens on the upper side of the mold cavity entrance half (3), (3),
The other end has mold cavity outlet halves (4), (4) opening on the left and right side surfaces of the split mold (1), (1), respectively. 1 more
5 (in this example, 2 locations) at the positions facing the split mold dividing surface of the double-bent cavity half surface (2) and (2).

Insert component holding grooves (12) and (12) are formed respectively.

The extruder (5) to which the parison is to be supplied is formed by a pair of mold cavity inlet halves (3), (3) when the pair of split molds (1), (1) are opened, as shown in Figure 1. It has a parison extrusion die (6) above the mold cavity entrance.

The extrusion die (6) has its lower end inserted between the inner peripheral surface of the mold cavity inlet and the mold cavity entrance formed by the pair of mold cavity entrance halves (3), (3) when the 10% mold is closed. The extrusion die (6) has a parison extrusion molding hole (7) on the lower end surface and an air blow nozzle (8) in the center thereof.
) was established.

The insert part (13) is a T-shaped body as shown in Figure 6, and is made of synthetic resin.

The blow molding method for a bent product having a piece-like insert part on the parting line is as follows. First, one of the split molds (1
) into the insert part holding groove half surface (12) to hold the insert 1 part (13), and then insert a pair of split molds (1
), (1) is closed and a pair of bent nest halves (2), (2)
A piece-shaped insert component (13) is held in a holding groove formed by a pair of insert holding grooves (12), (12).

Next, a parison (P) having a smaller diameter than the minimum inner diameter of the bent cavity is extruded from the forming hole (7) of the extrusion die (6) to form the mold cavity entrance half (3), (3) into the bent cavity. It is inserted and lowered from the mold cavity entrance consisting of
A suction cup (11) connected to a vacuum device is brought into contact with the mold cavity outlet consisting of ) and (4), and a suction action is applied to the mold cavity through the cup (11). 6) Air flows into the mold cavity from the small gap with the lower end, causes airflow to flow outside the parison (P), and flows out from the mold cavity exit through the cup (11), and in this example, Furthermore, air is blown out from the air blow nozzle (8) of the extrusion die (6), thereby forming a parison (P).
An airflow is also provided that flows inside the mold cavity and flows out from the mold cavity outlet to the outside via the cup (11), and both airflows introduce the parison (P) into the mold cavity.In this case, the parison (P) It is desirable that the atmospheric pressures inside and outside are approximately equal.

The tip of the parison (P) is connected to the cup (11) from the mold outlet.
When the parison protrudes slightly inward, the extrusion of the parison and the suction by the vacuum device are stopped, and then, as shown in the fourth figure, the tip of the parison (P) is moved between a pair of seal shutters (9) provided on the cup (11), (9) into the air cylinder (
10), the shutter (9) is clamped and sealed by closing with (10).

(9) is opened and the mold cavity outlet is closed by the cup (11). If this is done, the air blowing strongly from the air blow nozzle (8) will cause the parison to
P) is inflated and pressed against the curved cavity surface, and is welded to the insert parts (13), (13). After molding, the seal shutters (9), (9) are opened and the suction cup (11) is moved back, and then the split molds (1), (1) are opened to cut the molded product from the lower end surface of the extrusion die (6). To separate. The obtained bent molded product has almost no burrs, and a piece-like insert part (1
3) and (13) are provided protrudingly.

(Effects of the Invention) According to the blow-molding method for a bent product having an insert on the parting line of the present invention, it is possible to form a bent product in which a piece-like insert part to which Paris does not adhere is attached on the parting line. Since a large amount of burr is not formed on the parting line as in the method, the burr removal work from the molded product is simplified and work efficiency can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a partially cutaway side view of the line at the split mold closing stage, Fig. 2 is an enlarged sectional view taken along the line ■-■ of Fig. 1, and Fig. 3 is the parison introduction stage. Fig. 4 is a partially cutaway side view of the line, Fig. 4 is a side view of the parison tip sealing stage, Fig. 5
The figure is a side view of the same as above at the blow molding stage, and FIG. 6 is an enlarged perspective view of the piece-shaped insert component. P... Parison, 1... Split type, 2... Bent type nest half surface, 3... Type nest entrance half surface, 4... Type nest exit half surface, 1
3... Piece-shaped insert parts.

Claims (1)

[Claims] A pair of split molds each having a bent mold cavity half face having an upwardly opening mold cavity entrance half face at one end and a mold cavity exit half face at the other end as dividing faces, is used, is closed to form an open bent type nest having an upwardly opening mold cavity inlet at one end and a mold cavity outlet at the other end, and a required piece is placed at the position of the split mold dividing surface in the bent mold cavity. Next, a parison with a diameter smaller than the minimum inner diameter of the mold cavity is inserted into the bent cavity from the entrance of the mold cavity, and the inside of the bent cavity is inserted from the outlet of the flow mold cavity. It has an insert on the parting line that provides an outflow airflow, causes the parison to be introduced into the bent nest, and then seals the tip of the parison and blows air into the parison to form it. Blow molding method for bent products.