JPH08230022A - Blow molder - Google Patents

Abstract

PURPOSE: To provide a blow molder, in which the multi-stag flow control of the amount of pre-blowing in the blow molder can be easily executed, and the shape of parison may be easily controlled. CONSTITUTION: A circuit is provided, in which at least two compressed air flowing lines equipped respectively with flow control valves 41A and 41B, and solenoid valves 42A and 42B for communicating and shutting-off the amounts of air flowing through the flow control valves 41A and 41B are connected in parallel with a pre-blow line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding machine for molding a panel-shaped molded product, and more particularly to a blow molding machine having a function of easily and easily controlling a multi-stage flow rate control of a pre-blow amount to a flat parison. It is a thing.

[0002]

2. Description of the Related Art In blow molding in which a hollow resin product is made from a parison that is cylindrically injected or extruded from a die head, the parison is injected or extruded from the dice head and pre-blown into a bag-shaped parison by a parison pinch. Then, inflate it slightly, put it in the open mold and close the mold, and remove the air remaining between the mold and the parison from the small air vent hole that communicates with the mold surface through the vacuum pump device. After suction, high-pressure air is blown into the parison to form the parison into a predetermined shape based on the cavity and then cooled by a mold to complete the molding.
In this way, the molded resin product is taken out by opening the mold. The one shown in FIG. 3 shows a conventional blow molding machine. In FIG. 3, the molten resin is applied to the side 1 of the die head 2.
Shown is a so-called side-feed type blow molding machine 1 that is supplied from a location, in which a high-temperature molten resin pressed by an extruder 4 is provided between a die head 2 and a mandrel 3 via a resin supply port 2a. And 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. And, most of the conventional blow molding machines discharge a perfect circular parison because they mold a cylindrical shape such as a bottle shape, and the pre-blow control performed before the left and right mold clamping steps is: Strict control such as multi-step flow rate control is not required, and flow rate control at 1st speed
It was possible to obtain a cylindrical molded product having a substantially circular shape.
In a blow molding machine for molding such a cylindrical molded product, pre-blow control is performed, for example, as shown in FIG.
The operation is performed by one line in combination with the solenoid valve 32 (solenoid valve) for N-OFF control. On the other hand, FIG.
As shown in Fig. 1, resin is molded into a panel shape having a bag-shaped air space inside, and is used as a building material such as a door (gate) or simple wall material (partition wall), or a concrete casting mold. Although it has been studied to use it for floors such as frames and simple piers, these molded products have considerable structural strength in spite of their light weight and have the advantage of being strong against deformation.

[0003]

However, in a blow molding machine for molding such a panel-shaped molded article, the parison to be discharged is a flat parison, so that the shape retention of the parison during one-shot injection is better than in the conventional case. It becomes important, and there is a limit in the first speed control using only a timing timer in the molding of a circular parison or the like, and multi-stage flow rate control in which the flow rate is appropriately switched according to the transition of the elapsed time during injection is essential. Therefore, in the method of switching the variable flow rate adjusting valve in one pre-blow line shown in FIG. 5 by remote control, the variable flow rate adjusting valve having the maximum flow rate capacity is required, resulting in an increase in size and an increase in cost. At the same time, from the viewpoint of switching response, it is necessary to install it in the immediate vicinity of the machine side, so the space occupied in the installation place becomes large, and with a commercially available variable flow rate adjustment valve, it is restricted by the pressure limit constraint in the case of a large capacity flow rate, There has been a problem that a special amplifier for the operation power supply is required, resulting in high cost.

[0004]

[Means for Solving the Problems] By solving the above problems,
In order to perform the multi-stage flow rate control of the pre-blow amount easily and easily and at low cost, the present invention provides a blow molding machine equipped with a pre-blow line for injecting air into the parison discharged from the die. , A multi-stage flow rate control function for pre-blowing amount in which at least two or more compressed air flow lines each having a flow rate adjusting valve and a solenoid valve for communicating and shutting off the air amount flowing through the flow rate adjusting valve are connected in parallel It was configured with. Further, in the second aspect of the invention, the flow rate adjusting valve in each air flow line is a variable flow rate control valve, and a versatile multi-stage flow rate control can be used in which the flow rate range of the use range can be variously changed according to the product shape and the resin type. The pre-blow method was used.

[0005]

In the present invention, the combination of the flow rates flowing in the assembled pre-blow line is controlled by performing the ON-OFF control of the communication cutoff valves (electromagnetic valves) attached to the flow control valves of a plurality of stages in parallel. By changing it, the multi-step flow rate control of the pre-blow amount is implemented. In the second invention,
By selecting and setting the flow rate of each variable flow rate control valve in advance, it is possible to select various flow rates according to the application and expand versatility.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 relate to an embodiment of the present invention,
FIG. 1 is a pre-blowing amount multi-stage flow rate control circuit diagram, and FIG. 2 is a pre-blowing amount multi-stage flow rate control circuit diagram showing another embodiment. FIG. 1 shows one embodiment of the present invention, in which low pressure (about 7 to 8 kg / cm ² ) compressed air supplied from a compressed air supply source 50 is supplied to the pre-blow line 30,
It passes through the compressed air distribution line 40. The compressed air flow line 40 has a flow rate of, for example, 10 liter / m 2.
in flow control valve 41A, solenoid valve 42A for disconnecting this line, and 20 liter / min flow control valve 41
Lines A and B of B and a solenoid valve 42B that cuts off this line are arranged in parallel and connected. In the pre-blow line 30 thus configured, the solenoid valves 42A, 42
The pre-blow flow rate can be instantaneously changed in four cases of 0, 10, 20, and 30 liters / min by the combination of ON-OFF of B.

On the other hand, in the embodiment shown in FIG. 2, three types of flow rate adjusting valves are arranged in parallel to form a compressed air flow line 40, and electromagnetic valves 46A and 46B are respectively provided downstream of the flow rate adjusting valves 45A, 45B and 45C. , 46C are arranged to control each line ON-OFF, and the flow rates of the three flow rate control valves 45A, 45B, 45C are set to, for example,
When 5 liters / min, 10 liters / min, and 20 liters / min, seven types of flow rates of 5, 10, 15, ..., 35 liters / min as shown in the combination table in FIG. Each solenoid valve 46A,
It can be selectively used by ON-OFF control of 46B and 46C. In the embodiment of FIGS. 1 and 2, the flow rate adjusting valves have different flow rates, but of course the flow rate may be the same. Also, by making each flow rate adjustment valve a variable flow rate adjustment valve, the flow rate can be adjusted freely before operation, which greatly expands the flow rate adjustment range and is sufficient even if the molding specification conditions are significantly changed. The versatility is expanded by being able to follow. In the present invention, the flat parison for which the necessity of multi-step control of the pre-blow amount is relatively large is targeted, but of course, the present invention can be applied to a true circular parison for molded products having a large resin type and shape and a large drawdown. Further, it is possible to control the parison shape with high accuracy, it is easy to control the non-round circular parison shape, and it is suitable for maintaining the parison shape in the engineering plastic molding with a large drawdown.

[0008]

As described above, in the blow molding machine of the present invention, the multi-stage flow rate control of the pre-blow amount can be carried out easily, easily, with high accuracy and at a relatively low cost, so that the yield can be improved. Improves the productivity and improves the quality of molded products.

[Brief description of drawings]

FIG. 1 is a pre-blowing amount multi-stage flow rate control circuit diagram of a blow molding machine according to an embodiment of the present invention.

FIG. 2 is a pre-blowing amount multi-stage flow rate control circuit diagram of a blow molding machine according to another embodiment of the present invention.

FIG. 3 is an overall vertical sectional view of a conventional blow molding machine.

FIG. 4 is a perspective view of a conventional panel-shaped molded product.

FIG. 5 is a schematic explanatory diagram of a conventional pre-blow line.

[Explanation of symbols]

 1 Blow Molding Machine 2 Die Head 3 Mandrel 4 Extruder 6 Paricon Cylinder 7 Annular Space Passage 8 Mold 30 Pre-Blow Line 32 Solenoid Valve 34 Manual Flow Rate Control Valve 40 Compressed Air Distribution Line 41A, 41B Flow Rate Control Valve 42A, 42B Solenoid Valve 45A, 45B, 45C Flow control valve 46A, 46B, 46C Solenoid valve 50 Compressed air supply source 110 Panel-shaped molded product

Claims (2)

[Claims] 1. A blow molding machine comprising a pre-blow line for injecting air into a parison discharged from a die, wherein the pre-blow line is provided with a flow rate adjusting valve and an air amount flowing through the flow rate adjusting valve, respectively. A blow molding machine having a multi-stage flow rate control function of a pre-blow amount in which at least two or more compressed air flow lines having electromagnetic valves for disconnecting communication are connected in parallel. 2. The blow molding machine according to claim 1, wherein the flow rate adjusting valve in each air circulation line is a variable flow rate control valve.