JPH06335942A - Nozzle part structure of hot runner type injection mold - Google Patents

Abstract

PURPOSE:To reduce resin clogging in a hot runner type injection mold. CONSTITUTION:A ring shaped heat insulation ring 4 is provided between a hot runner nozzle bush 1 and a sprue bush 3, leaving a minute gap (g), and a nozzle piece 2 at the tip of the hot runner nozzle bush 1 is formed by Be-Cu alloy which has a high heat conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a proposal for reducing resin clogging in a hot-runner type injection molding die.

[0002]

2. Description of the Related Art As shown in FIG. 2, the structure of the nozzle portion of a conventional injection molding die has a structure in which a hot runner-nozzle bush a and a sprue-bush bush b are in close contact with each other. In this figure, c indicates a band heater, the hot runner-nozzle bush a is connected to the hot runner block, and the sprue bush b is located on the molded product side.

[0003]

In the case of the above-mentioned structure, the resin melted by the band heater c when molding a high temperature resin such as nylon glass is such that the tip of the hot runner-nozzle bush a is Because it was in close contact with the sprue-bush b, it was deprived of heat and solidified, resulting in clogging. Further, if the temperature of the band heater c is raised too much, the molten resin drips to the side of the sprue-bush b and causes clogging. It is an object of the present invention to solve the problem of preventing such an inconvenient situation from occurring.

[0004]

That is, according to the present invention, a heat insulating ring is provided between the hot runner-nozzle bush and the sprue-brush to provide a minute gap, and
In implementing this, it is further proposed to form the nozzle piece at the tip of the hot runner-nozzle bush with a Be-Cu alloy having good thermal conductivity.

[0005]

In the nozzle structure of the hot-runner-type injection molding die of the present invention having the above-mentioned structure, the hot-runner-nozzle bushing is formed by providing a ring-shaped heat insulating layer between the hot-runner nozzle bushing and the sprue-bushing. However, by preventing the heat from being taken by the sprue-bush, and by providing a minute gap, the molten resin becomes a semi-molten state in this gap and does not reach the sprue-bush. If the gap is 0.5 mm or less, the resin hangs down on the sprue-bush, and if it is too large, the resin solidified during molding cannot be pierced, so 0.5 to 1 mm is appropriate.

Further, by forming the nozzle piece at the tip of the hot runner-nozzle bush with a Be-Cu alloy having good thermal conductivity, it becomes easy to hold the resin in the minute gap in a semi-molten state, and the semi-molten resin is formed at the time of molding. It is easy to break through the resin layer in the state.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is a hot runner-nozzle bush on the side of a hot runner block (not shown), and a nozzle piece 2 is formed at the tip thereof. It is formed with a good Be-Cu alloy.

The sprue-bush 3 which faces the hot runner-nozzle bush 1 is connected to the molded product side not shown in the figure.

In the present invention, the hot-liner is
Between the nozzle bush 1 and the sprue-bushbone 3, the heat conduction of the hot runner bush and the sprue bush is minimized, and the ring-shaped heat insulating layer 4 is interposed, whereby the hot runner-nozzle bush (actually Provides a minute gap g between the nozzle piece 2) and the sprue-bush 3, and this gap g is practically 0.
About 5 to 1 mm is suitable. In the figure, 5 is a band
Data.

According to the nozzle portion structure of the present invention having the above-mentioned structure, the hot runner-nozzle bush and sprue-
Since the contact surface of the bush is small, the heat of the band heater is not taken away so that the resin is not clogged. Further, the resin melted by the band heater 5 is
In the gap g, a semi-molten state is reached and the sprue-bush 2 is not reached, so there is no risk of resin clogging.

Further, by forming the nozzle piece 2 from a Be-Cu alloy having good thermal conductivity, the resin in the gap is brought into a semi-molten state, and even if it is solidified, it is easy to break through the resin layer during molding. It has been done.

[0012]

As described above, according to the present invention, the presence of the gap causes the molten resin to be in a semi-molten state in this gap, and accordingly, the molten resin drips toward the sprue-bushtail side. The nozzle piece is formed of a Be-Cu alloy having good thermal conductivity so as to break through the resin layer solidified in the gap at the time of molding, while eliminating the possibility of causing clogging that hinders the molding work. The effect of being easy is also obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a conventional example.

[Explanation of symbols] 1 Hot runner-nozzle bush 2 Nozzle piece 3 Sprue-bush 4 Heat insulating ring 5 Band heater g Gap

Claims (2)

[Claims] 1. A nozzle part structure in a hot runner type injection molding die, wherein a minute gap is provided between a hot runner nozzle bush and a sprue bush by providing a heat insulating ring. 2. A nozzle in a hot-runner-type injection molding die according to claim 1, wherein the nozzle piece at the tip of said hot-runner-nozzle bush is formed of a Be-Cu alloy having good thermal conductivity. Part structure.