JPS63176123A - Runnerless injection molding equipment - Google Patents

Abstract

PURPOSE:To provide an inexpensive high-precision device through extremely simple constitution, by a method wherein heat energy is stored in a heat accumulation part and a gate part is heated locally by feeding the heat energy to a heating space formed on the gate part by a pressurizing device such as a piston through a heat flow path. CONSTITUTION:As a heat accumulation part 21 and cylindrical hollow chamber have been formed on a manifold 5, air in the said part 21 is heated by a heater 6 of a manifold 5 and the temperature is raised. When molten raw material resin is injected by an injection molding device 2 under that condition, the inside of a cavity 8 is filled with the molten resin of a desired quantity on the inside of a sprue 3 on the inside of a mold 4 through a runner part 11 and gate part 12. At the time of injection operation, when a pressurizing device 24 is actuated, and stroke motion of a piston 22 is developed through a control device 23 such as an air cylinder based in the heated air in the inside of the heat accumulation part 21, the heated air corresponding to a quantity of the stroke arrives at a heated space H of a gate part 12 by passing through a heat flow path 25, the space H is heated, and the raw material resin on the inside of the gate part 12 is molten through heating.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is a runnerless injection method that uses a heat source provided in the mold to heat the gate portion leading to the cavity to perform high-precision molding. Regarding molding equipment.

(Prior Art) Conventionally, this type of runnerless injection molding apparatus called a hot runner method is known as the Spear System, a trademark developed by the present inventor, which heats the gate part by 1 m. By locally heating the gate part with a heater from the inside or outside, the molten resin in the gate part can be solidified, and precision molding can be performed by switching the melting operation, eliminating the need for sprue runners that waste raw material resin. It is highly valued both domestically and internationally as a system capable of high-precision molding similar to the -C method.

[Problem that the invention seeks to solve]

Using a conventional heater as a heating means for such a gate part cannot avoid high-volume processing and high costs, and moreover, it is difficult to control the temperature of the heater in connection with injection molding operations. For control purposes, it became essential to install a controller, and it was extremely difficult to provide a high-precision runnerless injection molding machine except for economical reasons.

Means for Solving Problem C] The present invention has been made by focusing on the above points, and is a means for plasticizing raw materials that has been commonly used in the past.

Utilizing the injection molding means, mold structure, etc. as is, the mold is heated by a heating means such as a cartridge heater installed in the surface mold, and the thermal energy stored in the mold is stored in the heat storage part, and is formed in the gate part. The above problem was solved by locally heating the gate portion by supplying heat to the heating space via a heat flow path using a pressurizing means such as a piston.

This makes it possible to omit an expensive controller and a high-temperature, expensive heating means for the gate portion, making it possible to provide an inexpensive runnerless injection molding apparatus with an extremely simple configuration.

[Effect]

The hot melted raw material obtained by the raw material plasticizing means and supplied to the runner section is molded by injection molding means by filling a required amount of molten resin into a cavity through a gate section.

By the way, a thermal space is formed in the gate section, and the thermal energy held by the mold is instantly and efficiently supplied from the heat storage section through the heat flow path by pressurizing means, so that the raw resin in the gate section is Depending on the temperature of the part, it exhibits a phase change of solidification, semi-solidification, and melting, and can be operated with sensitivity to open and close the so-called gate.

Therefore, it is possible to effectively control the temperature of the raw resin inside the gate section each time a °C1 injection molding operation is performed by appropriately controlling the pressurizing means, thereby ensuring the injection molding operation of the raw resin into the cavity. Furthermore, it is possible to perform highly accurate injection molding by preventing the unnatural nose dripping phenomenon from the gate portion.

Second, the fluid that has undergone heat exchange in the heating space of the gate part passes through the air gap between the molds and is discharged to the outside without any problem.

〔Example〕

Examples of the present invention will be described below with reference to the drawings.

1 is a means for thermoplasticizing raw materials, 2 is an injection molding method for molten resin 1
Step 3 is a runner formed in a mold, especially a fixed mold 4;
is a manifold forming two or more injection channels, and a necessary number of heating means 6 such as cartridge heaters are provided at necessary locations.

7 is an intermediate mold 9 that communicates with the manifold 5 and the cavity 8
A runner heating means is disposed therebetween, and is accommodated in a tube-shaped support holder 10.

Incidentally, the runner heating means 7 does not need to be particularly specified, but it is possible to select and use a self-heating type such as a heater or a high-frequency electromagnetic induction coil, or a heat-dependent type such as a heat vibrator filled with heat transfer fluid. be able to. Self-heating types may require a controller, but heat-dependent types do not require a controller at all. 8a is a movable mold.

In this embodiment, a heat-dependent heat pump and eve are used, and the runner is formed in the shape of a whole or double pipe ring, and corresponds to a straight hole with a desired diameter R as the part of the so-called runner 3. A portion 11 is formed.

Reference numeral 12 denotes a gate portion that communicates with the runner heating means 7 and the connecting tongue cavity 8, and a heating space H is formed on the outer periphery of this gate portion, and an annular collar 13 is provided at the base of the gate portion, and a heat vibrator is provided. It engages with the tip step portion 14, and opens the gate 16a of the cavity 8 through the narrow taper portion 15, through the gate hole 16 having a diameter R2 smaller than the diameter R1, and further through the taper portion 17. . The runner section 11 and the gate section 12 are disposed on the same axis, that is, on the same axis, tIIb. Preferably, the gate portion 12 is made of copper, a metal such as copper, beryllum, or other material having good thermal conductivity.

I8 is an outer circumferential fixed body that is disposed on the outer circumference of the support holder 10 that supports the runner heating means 7 and the gate portion l2, and can also form the heating space H, and is fixed by the positioning ring 19 of the intermediate mold 9. solidly supported.

20 is the second positioning ring 19. An air gap formed between the outer peripheral fixing body 18 and the intermediate mold 9 is shown.

21 is a heat storage part provided in the mold, especially the manifold 5;
It has a hollow cylinder structure, a piston 22 is movably disposed therein, and a control means 23 such as an air cylinder forms a pressurizing means 24 for heated air. Reference numeral 25 denotes a heated air passageway, that is, a heat flow path leading from the heat storage section 21 to the heating space H of the cage section 12 described in +iif.
The passage 25a on the discharge side of the heating space H is formed by the passage 25a formed in the support holder 10 and the passage 25b bored in the outer peripheral fixed body 18.
It communicates with 0. 27 is a movable mold.

The operation will be explained based on the above configuration.

First, the raw material to be used is melted by heat 6f plasticizing means l to make it possible to be injection molded, and a mold 4 is fixed to the mold.
The thermal energy of a large number of heaters 6 disposed in a manifold 5 is transmitted to a support holder 10 that collides with the manifold 5, and the runner heating means 7 consisting of a heat pipe is heated as needed by receiving heat conduction from the support holder 10. Heat it up to temperature.

At the same time, the necessary thermal energy is also supplied to the gate portion 12, which is a separate member and is in contact with the runner heating means 7.

On the other hand, since the heat storage part 21 is formed in the manifold 5 and a cylindrical hollow chamber is formed, the air in the core part 21 is heated by the heater 6 of the manifold 5 and its temperature is increased.

In such a state, when the molten raw material resin is injected by the injection molding means 2, the molten resin in the runner 3 in the mold 494 flows into the runner section 11. A desired amount of molten resin is filled into the cavity 8 through the gate portion 12 .

During this injection molding operation, the pressurizing means 24 acts on the heat storage section 2.
When the piston 22 exhibits a stroke motion by the control means 23 such as an air cylinder, the heated air in the piston 22 passes through the heat flow path 25 according to the stroke and reaches the gate section! 2, the heating space H is heated, and the raw resin in the gate portion 12 is heated and melted.

The heat radiation acting on the gate portion 12 can be variably adjusted by adjusting the flow rate of heated air, heating time, heating temperature, etc., and phase changes such as assimilation, semi-solidification, and melting can be freely performed.

When the pressurizing means 24 is activated, the heated air is heated in the heating space H of the gate part 12 and becomes low-temperature air. Exhausted to the outside of 4.

This pressurizing means 24 may be provided with a heat generating function such as a heater, but usually the heat retention energy of the manifold 5 is sufficient. Once the heated air is discharged, it can be moved back by -1 and the same stroke plane movement can be performed again in conjunction with the injection molding operation to perform a repeat operation.

At that time, it goes without saying that a mold opening r+A operation is performed to take out the molded product inside the cavity 8.

In this mold opening operation, by leaving the gate portion 12 without heating it, the gate hole is closed. (Since the raw material resin in the Sa part can be solidified and the so-called gate can be kept in a closed state, the sagging phenomenon can be prevented.

Moreover, the runner part 11 and gate part 12 of the runner 3 are
- Since it is formed in a straight line and there is no resistance part, the injection pressure can be significantly reduced, and since the air gap 20 is formed, dissipation of temperature and loss of thermal energy are prevented.

Moreover, since the runner part 11 and the gate part 12 are connected to each other by separate members so as to effectively maintain heat conduction, it is necessary to make the thermal energy acting on the heating space H of the gate part 12 larger than necessary. There is also an advantage that the remaining heat of the heater 6 of the mold 4 can be used.

(Effects of the Invention) According to the present invention, the heat of one stage of heating the mold is used as a heating means for a very small area called the gate, and the thermal energy of the heat storage part provided in the mold part is heated. By rE means,
Since the heat is pumped into the heating space of the gate through a heat flow path to locally heat it, the heating operation of the gate can be performed with good response, and the raw resin in the gate can be heated by pressurizing means. By changing the phase to an open state such as assimilation, semi-solidification, or melting depending on the pumping state of heated air, it is possible to perform runnerless injection molding with a high opening degree and no waste.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional top view of essential parts of an embodiment of a runnerless injection molding apparatus according to the present invention, and FIG. 2 is an explanatory view of the same as seen from the front. 1... Raw material thermoplasticization means 2... Injection molding means 3...- Run runner 4... Mold 5... Manifold 6- ----- Heating means such as a heater 7 ... Runner heating means 10 --- Support holder 11 ... Runner section 12 ... Gate section 20 ... ... Air gap 21 ... Heat storage section 24 ... Pressure means 25 ... Heat flow path H --- Heating space

Claims (2)

[Claims] (1) A runnerless injection molding device that allows thermoplasticized raw materials to be injected into a desired cavity through a runner section and a gate section through a runner provided in a mold using an injection means such as a piston. A heating space is formed in the gate part, and thermal energy obtained by a heating means provided in the mold is transferred from a heat storage part to the heating space via a heat flow path using a pressurizing means such as a piston. A runnerless injection molding apparatus characterized in that the gate part can be locally heated by heating the gate part. (2) The heat storage part for thermal energy in the mold is bored into a cylindrical shape, and a piston that moves back and forth intermittently is installed in this heat storage part as a pressurizing means, and the heat flow path communicating with the heating space of the gate part is Claim 1, characterized in that it is formed by being bored in a support holder disposed on the outer periphery of the runner part.
Runnerless injection molding equipment as described in Section 1.