JPH09141705A - Injection molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress emboss transfer insufficiency of the surface of a mold while improving gas gloss inferiority by forcibly excluding a gas component. SOLUTION: A thermoplastic resin is injected from a gate to flow through a mold and the difference between the time when the resin passes the first pressure sensor 21 preliminarily provided in the mold along the flow of the resin and the time when the resin passes the next second pressure sensor 22 is measured by a count means 4 and numerically processed to calculate flow velocity. Thereafter, when the resin passes the first and second pressure sensors 21, 22 at the numerically processed flow velocity, the gas in the mold is removed within a numerically processed time by a suction means 5 through the gas venting groove 33 arranged to the outer periphery of the gas venting piece 32 preliminarily provided in the vicinity of the second pressure sensor 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding apparatus, and more particularly to an injection molding apparatus for performing appearance molding on unpainted products such as display devices.

[0002]

2. Description of the Related Art The conventional degassing structure of an injection molding apparatus is
Predicting the flow of resin, from the processed surface of the mold, (A) of Fig. 2
As shown in FIG. 2, a method of forming the rib 132 with a piece structure and removing it from the gas release groove 133 provided at the end of the entire piece, and an ejector used when releasing the molded product shown in FIG. 2B from the mold A method of venting gas from the outer peripheral surface of the protruding pin called pin 232, and a gas venting gap 333 (3 / 100-
It is common to degas from about 4/100).

[0003]

As described above, in the conventional degassing method for the injection molding apparatus, the "gas degassing" is arranged in the mold, but it is not a forced expulsion method. Due to the effect, most of the "gas release" is generally "gas release" from the parting line, so "gas release" from the middle stage of molding and filling is insufficient, and turbulent flow containing gas Occurs and gloss occurs.

Therefore, an object of the present invention is to perform injection molding in which the gas component is forcibly removed from the mold while the gas component is not mixed so as to suppress the insufficient grain transfer on the mold surface and to improve the gas gloss defect. Provide a device.

[0005]

In order to solve the above-mentioned problems, the injection molding apparatus of the present invention has a first pressure sensor provided in a mold and a predetermined distance from the first pressure sensor. The second pressure sensor provided in the mold and the tip of the molten thermoplastic resin injected into the mold detect the time difference between the first pressure sensor and the second pressure sensor and count the flow velocity. Counting means, a degassing portion that is degassed by the flow velocity counted by the counting means, and a suction means that degass the degassing portion at a predetermined flow velocity based on the flow velocity counted by the counting means. It is characterized by being configured.

In order to solve the above-mentioned problems, in the injection molding apparatus of the present invention, the time difference for the tip of the molten thermoplastic resin to pass from the first pressure sensor to the second pressure sensor is set to a numerical value. Based on the counting means for counting with the processed electric signal and the electric signal counted by the counting means,
It is characterized by comprising the above-mentioned suction means for degassing at a predetermined flow velocity.

[0007]

Next, an injection molding apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a degassing die of an injection molding apparatus according to an embodiment of the present invention.

As shown in FIG. 1, an injection molding apparatus according to an embodiment of the present invention has a first pressure sensor 21 provided in a mold and a predetermined distance from the first pressure sensor 21. The second pressure sensor 22 provided and the tip of the molten thermoplastic resin injected into the mold are connected to each other by the first pressure sensor 2
A counting means 4 for detecting the time difference between the first pressure sensor 22 and the second pressure sensor 22 to count the flow velocity, and a degassing space 31, a degassing piece 32, and a gas that are degassed by the flow velocity counted by the counting means 4. A gas vent having a vent groove 33,
Based on the flow velocity counted by the counting unit 4, the suction unit 5 degasses the gas venting unit at a predetermined flow velocity.

Further, the counting means 4 of the injection molding apparatus of the present invention
Is counted by an electric signal obtained by numerically processing the time difference for the tip of the molten thermoplastic resin to pass from the first pressure sensor 21 to the second pressure sensor 22, and the suction means 5 is counted by the counting means 4. Gas is degassed at a predetermined flow rate based on the electric signal.

Next, the operation of the injection molding apparatus according to one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the operation of the injection molding apparatus according to the embodiment of the present invention is such that the thermoplastic resin is injected from the gate 11 of the core 1 and flows through the mold, and along the flow of this resin. Then, the counting means 4 measures the difference between the time when the first pressure sensor 21 previously provided in the mold is passed and the time when the second pressure sensor 22 is passed next. Ask.

Thereafter, when the resin passes through the first pressure sensor 21 and the second pressure sensor 22 due to this flow velocity, the gas installed on the outer periphery of the degassing piece 32 provided in the vicinity of the second pressure sensor 22 in advance. The gas vent space 31 is passed through the vent groove 33 so that the gas can be forcibly sucked into the mold.
By operating the suction means 5 such as an accumulator connected to the connection port through the electric signal with the electric signal obtained by numerically processing the above-mentioned time difference, the gas component is completely removed from the inside of the mold, and the appearance is the same as in the short shot. It is possible to obtain a clean molded product without gas content.

[0014]

As described above, the gas component from the molten resin mixed in the resin during the molding process can be surely removed, and the gas component is forcibly removed from the mold before the gas component is mixed. It has the effect of suppressing the insufficient transfer of grain on the surface of the mold by discharging the amount and improving the gas gloss defect.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a degassing mold of an injection molding apparatus according to an embodiment of the present invention.

FIG. 2 shows a conventional method of degassing a rib portion (A), a method of venting gas from an ejector pin portion (B), and a method of venting gas (C) installed on the outer peripheral surface of a product by a degassing method of an injection molding apparatus is there.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold (core) 4 Counting means 5 Suction means 11 Mold (gate) 21 First pressure sensor 22 Second pressure sensor 31 Gas venting part (gas venting space) 32 Gas venting part (gas venting piece) 33 Gas Venting part (gas venting groove)

Claims (2)

[Claims] 1. A first pressure sensor provided in a mold, a second pressure sensor provided at a predetermined distance from the first pressure sensor, and molten heat injected into the mold. A counting unit that counts the flow velocity by detecting the time difference when the tip of the plastic resin passes from the first pressure sensor to the second pressure sensor, and a degassing unit that degass by the flow velocity counted by the counting unit. An injection molding apparatus comprising: a suction unit configured to degas the degassing unit at a predetermined flow rate based on the flow rate counted by the counting unit. 2. The counting means for counting the time difference between the first pressure sensor and the second pressure sensor when the tip of the molten thermoplastic resin passes through the second pressure sensor, and the counting means, and the counting means. The injection molding apparatus according to claim 1, wherein the injection molding apparatus is configured with the suction means that degasses at a predetermined flow rate based on the generated electric signal.