JPS60193629A - Injection blow molding die - Google Patents

Abstract

PURPOSE:To cut a gate for injection molding automatically at the same time as the mold-clamping of blow molding by mounting a cutter for the gate in a cavity so as to be operated along the direction of mold-clamping of blow molding. CONSTITUTION:A primary molded shape 3 is kept at the temperature of a plastic region, and moved to the opposite position of a cavity 7 as it is left as it adheres on a core 6. When the mold-clamping of blow molding is executed, the cutting 8 of a cutting tool 9 fitted to the cavity 7 intrudes to the surface of the primary molded shape 3, and is brought into contact with the surface of the core 6, a runner 4 is separated from a gate 5 and an opening end 2' is shaped, and the cutting tool 9 retreats in the cavity 7. Mold-clamping is completed, air is blown off from the inside of the core 6, and the molded shape 3 is swollen until it is in contact with the surface of the cavity 7, thus shaping a secondary molded shape. Accordingly, the gate of the primary molded shape can be cut automatically at the same time as the mold-clamping of blow molding, the gate need not be cut through another processing after injection molding, and a homogeneous molded shape with an opening is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a molding die used for injection blow molding.

"Background of the Invention" In injection blow molding, the primary molded product after injection molding is transferred into the blow mold while being kept at a temperature in the plasticity range while remaining attached to the core mold, and after mold clamping is completed, the primary molded product is transferred from the inside of the core mold. This is a molding method in which air is blown out to inflate the mold in a cavity of a blow mold to obtain a molded product 1 having a predetermined shape with a protruding body as shown in FIG. 1, for example. When performing injection blow molding on a molded product with an opening 2 as shown in Fig. 1, various methods can be considered for the runner and gate required when forming the first injection molded product. Methods that do not leave gate marks on the surface include the side gate method, submarine gate method, and disc gate method. Among these, the disk gate method, in which the runner 4 is connected by a gate 5 over the entire circumference of the open end 2 of the primary molded product 3, as shown in Figure 2, prevents the occurrence of welds because the filled resin does not flow during injection molding. It is most suitable for injection blow molding because it produces a homogeneous molded product. However, in the disk gate method, cutting of the gate 5 in the secondary processing after completion of molding is difficult because the gate 5 is connected to the entire circumference of the opening 2 of the primary molded product 3. However, the larger the diameter of the gate portion, the more difficult the cutting operation becomes, resulting in a disadvantage that it requires a large number of man-hours.

``Object of the Invention'' The object of the present invention is to automatically perform gate cutting using a disc gate method in injection blow molding at the same time as mold clamping for blow molding.

"Summary of the Invention" An injection blow molding mold according to the present invention is an injection blow molding mold for molding a molded product having an opening, in which a cutting device for cutting a gate for injection molding is used as a mold clamp for blow molding. By providing the gate in the cavity for blow molding so as to operate along the direction, the gate cutting of the primary molded product is automatically performed at the same time as the mold clamping for blow molding.

"Embodiments of the Invention" Examples of the present invention will be described with reference to the drawings. FIG. 3 is a sectional view of a main part of an embodiment of an injection blow molding mold according to the present invention, and FIG. 4 is a sectional view of a main part of the above embodiment after clamping. 3 and 4 are cross-sectional views showing the main parts of the core 6 and the upper half of the cavity 7 of the blow mold, respectively. A cutting tool 9 having cutting tools 8 at opposing positions is embedded in the cavity 7 and can be moved forward and backward along the mold clamping direction A. The above cutting tool 9 cut F! #8 tip is mMI
The cutting tool 9 protrudes from the surface of the cavity 7 so as to come into contact with the surface of the core 6 during the molding process, and when the tip of the cutting lFr8 comes into contact with the surface of the core 6, a cutting tool 9 is cut when a mold clamping force is applied.
The cutting tool 9 is held by the spring 10 so that the cutting tool 9 is retreated into the cavity 7, and gaps 11 and 11' are provided in the cavity 7.

In molding using the injection blow molding mold configured as described above, injection molding is first performed to form the primary molded product 3, and the primary molded product 3 is maintained at a temperature in the plastic range. While still attached to the core 6, it is moved to a position facing the blow molding cavity 7, as shown in FIG. Next, when the mold is clamped for blow molding, the cutting tool 9 provided in the cavity 7 bites into the surface of the primary molded product 3, as shown in FIG. At the time of contact, the runner 4 of the primary molded product 3 is separated from the gate 5 to form an open end 2'. Thereafter, the cutting tool 9 retreats within the cavity 7 as the mold clamping progresses. After the mold clamping is completed, air is blown out from inside the core 6 to inflate the primary molded product 3, which maintains the temperature in the plastic region, until it touches the surface of the cavity 7 as shown by the dotted line in Figure 4, thereby forming the second molded product. form.

In the above-mentioned no-injiexidano blow molding mold, if the tip of the cut 8 provided on the cutter 9 of the cavity 7 is adjusted so as to come into contact with the surface of the core 6 when the mold clamping is completed, the spring 10 and the air gap 11 + Cutting tool 9 using 11
Although the retraction device is not necessarily required, it is better to provide it in order to prevent damage to the cut 8 when the gate 5 is solidified or there is foreign matter in the primary molded product 3.

Note that the gate to be cut according to the present invention is not limited to the gate of the L disk gate type, but can be similarly applied to gates of other gate types.

"Effects of the Invention" In the injection blow molding mold for molding a molded product having an opening according to the present invention, a cutting device for cutting a gate for injection molding is installed in a cavity for blow molding along the mold clamping direction. Since the gate of the primary molded product is cut at the same time as the blow molding, there is no need to cut the gate by separate processing after injection molding. Since it is possible to cut the hole, a hollow injection blow molded product having an opening can be obtained at a low cost.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of an injection blow molded product having an opening, Fig. 2 is a sectional view of a runner and gate portion of a primary molded product using a disc gate, and Fig. 3 is an injection blow molded product according to the present invention. FIG. 4 is a cross-sectional view of a main part of an embodiment of a molding die, showing a state after clamping of the mold in the above embodiment. 2...opening! ... Opening end, 5... Gate for injection molding, 7... Cavity for blow molding, 8... Cutting (cutting device), 9... Cutting tool (cutting device). spear 2 diagram

Claims (1)

[Claims] In an injection blow molding mold for molding a shaped product having an opening, the cutting device for cutting the injection molding gate is installed inside the blow molding cavity so as to operate along the mold closing direction of the blow molding. An injection blow molding mold characterized by being provided with.