JP2833698B2 - Resin molding runnerless method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of plastic working for molding a plastic resin or the like, and relates to a technique of a resin molding runnerless system.

[0002]

2. Description of the Related Art Conventionally, in a resin molding using an injection molding machine, a nozzle is brought into close contact with a pouring surface of a mold, and molten resin is injected from the pouring surface into a molding cavity. The nozzle is closed by a pin that acts as a valve and has a built-in valve, and molding is performed. That is, a gate runner portion is provided from the gate of the molding cavity provided in the mold, and the nozzle of the molding machine is brought into close contact with the external opening thereof,
The molten synthetic resin is injected from the nozzle into the mold cavity of the mold and molded. The gate runner portion provided on the conventional mold side is omitted, and a molded product taken out after molding is molded without a runner set (in a state where the gate runner is molded). The method cannot greatly simplify the structure because the mechanical structure complicates the forming sequence. Furthermore, due to the characteristics of injection molding, it is necessary to maintain the mechanical strength of the gate portion of the molding cavity of the mold, and the gate is made as small as possible. For this reason, it is inevitable that the injection time (one-shot time) of the molten synthetic resin must be made longer so that the molding efficiency is largely hindered as a whole, which may cause an increase in production cost.

[0003]

SUMMARY OF THE INVENTION The present invention is directed to a runner-less system in which a gate runner on a molding die side is omitted and injection molding is directly performed on a gate of a molding cavity. In consideration of the necessity of making the gate as small as possible in order to obtain the mechanical strength of the gate of the mold, the size of the gate is relaxed in a larger direction to form one mold. Time (one-shot time) can be reduced, resulting in a reduction in overall molding time,
It is an object of the present invention to be able to expect shortening.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a resin injection molding machine for enlarging a gate of a molding cavity of a mold corresponding to a gateless runner and obtaining mechanical strength of the mold at the gate. Nozzle and the gate runner of the mold are integrated, and the tip surface of the nozzle and the shape of the needle pin provided in the nozzle are formed in a horn shape at the tip portion. Then, when the front end face of the nozzle and the front end face of the nozzle coincide with each other, the tip end face of the nozzle is reset.
The dolphin's horn-shaped tip surface is made slightly smaller than the nozzle opening surface, and the tip surface of the nozzle opening is opened in a ring shape to increase the injection speed of the molten synthetic resin hot water, and then the molten synthetic resin is melted. After one injection (one shot) of the resin is completed, the vibration frequency of the ultrasonic vibrator 20 linked to the needle pin is moved against the horn-shaped tip surface of the needle pin provided in the nozzle. ~ 30 micrometers (about 25K
hz) to transmit the ultrasonic vibration to easily separate the gate face and the nozzle end face of the molded product formed in the molding cavity, thereby shortening one injection time (one shot time) of the molten synthetic resin. Was the solution.

[0005]

1 (a) and 1 (b) are schematic side sectional views of a conventional embodiment. FIG. 2A shows a state in which a pin 3 for opening and closing a nozzle port 2 of a nozzle 1 of an injection molding machine is provided, and the nozzle port 2 is connected to a gate runner 6 a of a gate 6 of a molding cavity 5 of a mold 4.
At the same time, the pin 3 of the nozzle 1 retracts and the nozzle port 2 opens, and the mold cavity 5
The molten synthetic resin is injected into the mold to obtain a molded product 5a.
As described above, the gate 6 is formed as small as possible in order to maintain the mechanical strength around the gate 6 of the molding cavity 5 of the mold 4. FIG. 1B is a schematic external view of the molded product 5a of FIG. Get runner on molded product 5a
Is removed in a later step.

FIG. 2 is a schematic side sectional view of one embodiment of the present invention. A pin 9 is provided inside the nozzle 7 of the injection molding machine and provided with a large opening in the nozzle port 7a.
The tip of the pin 9 is provided with a horn-shaped portion 10, which is smaller in diameter than the nozzle port 7 a, so that the hole shape of the nozzle 7 a is open in a ring shape 8. The gate 14 of the molding cavity 13 of the mold 12 is made to have the same diameter as the nozzle port 7 so as to be in close contact with the nozzle port 7a of the nozzle 7 and at the same time (the pin 9 of the nozzle 7 is retracted to open the nozzle port 7a). The molten synthetic resin is injected from the gate 14 of the mold 12 into the molding cavity 13, and then the vibration frequency of the ultrasonic vibrator 11 linked to the pin 9 is 20 to 30 μm. T─ (about 2
The ultrasonic vibration of 5 Khz) is transmitted to the front end face of the horn 10 so that the surface of the gate 14 of the molding cavity 13 and the nozzle
a, when the surfaces of the ring-shaped opening 8 coincide with each other, the ultrasonic vibration allows the injection-molded product 13a to be easily separated from the surface of the nozzle opening 7a, and the injection time of one molten synthetic resin ( One shot time) can be shortened.

[0007]

As mentioned above, the tip of the pin 9 is
In this case, the nozzle port 7a is formed into a ring-shaped port 8 so that the nozzle port 7a has a large opening, and the gate 14 of the molding cavity 13 has a diameter equal to that of the nozzle port 7. When the injection amount speed of the resin hot water is increased and the molding time can be reduced as compared with before, when the surface of the spout 14 and the surfaces of the nozzle port 7a and the ring-shaped port 8 coincide with each other, the ultrasonic vibrator is used. The product 13a formed by injection molding can be easily separated from the surfaces of the nozzle port 7a and the ring-shaped port 8 by ultrasonic vibration having a vibration frequency of 20 to 30 micrometers (approximately 25 Khz). One injection time (one shot time) of the resin can be reduced.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are schematic views of a conventional embodiment.

FIG. 2 is a schematic side sectional view of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Nozzle port 3 Pin to be opened / closed 4 Mold 5 Mold cavity 5a Molded product 5b Header 6 Gate 6a Runner, gate 7 Nozzle 7a Nozzle port 8 Ring port 9 Pin 10 Pin 9 Shape part 11 Ultrasonic vibrator 12 Mold 12 13 Mold cavity 13a Molded product 14 Gate

Claims (1)

(57) [Claims] In a resin molding machine, a nozzle tip surface of a nozzle in which a resin injection nozzle and a mold runner are integrated, and a tip horn shape of a needle pin provided in the nozzle. When the tip surface of the nozzle coincides with the same surface, the tip surface of the nozzle is opened in a ring shape by the horn shape of the needle pin of the tip surface, and the molten synthetic resin is injected (one shot). After the end, the vibration frequency of the ultrasonic vibrator interlocking with the needle pin with respect to the horn-shaped tip surface of the needle pin provided in the nozzle is next determined.
A resin molding runnerless system that transmits ultrasonic vibration of 0 to 30 micrometers (approximately 25 Khz) to easily separate the gate port and the nozzle port tip of the molded product in the molding cavity.