JP2011062864A - Structure of gas entrainment suppressing nozzle of molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure which is simple in structure, reduces costs, and removes gas contained in a molten thermoplastic injection molding material efficiently before the thermoplastic injection molding material is molded in the structure of the gas entrainment suppressing nozzle of a molding machine. <P>SOLUTION: In the injection nozzle 16, a channel 29 for a material comprising a flow-in channel 30 having a prescribed inner diameter D1 at a side to which the molten thermoplastic injection molding material flows, a tapered channel 32 which communicates with the flow-in channel 30 and is formed in a tapered shape, and a channel 33 for injection which communicates with the tapered channel 32, is formed to have an inner diameter D2 smaller than the inner diameter D1 of the flow-in channel 30, and injects the thermoplastic injection molding material into a mold 10 is formed, and a porous property part 34 for drawing out gas contained in the molten thermoplastic injection molding material to the outside in a place corresponding to the tapered channel 32 is provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas entrainment suppression nozzle structure of a molding machine, and more particularly to a gas entrainment suppression nozzle structure of a molding machine that removes gas contained in a molten thermoplastic injection molding material to the outside.

As a molding machine, for example, a thermoplastic injection molding machine melts (plasticizes) and flows a thermoplastic injection molding material (resin), and injection-fills (pours) into a cavity in a mold from an injection nozzle. The molded product is made by cooling and solidifying in this mold. A thermoplastic injection molding material is produced by adding a reinforcing agent, a filler or the like to a base resin, and melts when heated from a solid state, and becomes solid when cooled from this molten state.
Moreover, for example, an extruder as a molding machine includes one that causes a thermoplastic injection molding material (resin) to flow and is extruded as a molded product from an extrusion hole of a molding nozzle.

JP, 11-170320, A The injection device concerning patent documents 1 is ahead from the position where fusion (plasticization) of a thermoplastic injection molding material is completed in order to vent gas (gas) contained in a thermoplastic injection molding material. In this part, a porous degassing member is separately provided.

However, in the past, for example, in a thermoplastic injection molding machine, the point where the gas (gas) generated by the chemical component contained in the base resin of the thermoplastic injection molding material was removed was not the tip of the injection nozzle, so At the time of injection filling, the gas contained in the molten thermoplastic injection molding material is compressed before passing through the injection nozzle and stays at the tip, and the gas is injected and filled into the mold in a state where the gas stays. The gas is entrained in the mold and enters the formed product. For this reason, the occurrence of defects in the molded product increases due to short shots, blisters (convex parts), sink marks (concave parts), uneven gloss, etc., and productivity decreases. At the same time, there is a problem in that the mold corrosion is induced and the mold maintenance cycle is shortened.
Further, the extruder also has a problem that a molded product contains a large amount of gas.
In order to eliminate this problem, in order to vent the gas contained in the molten thermoplastic injection molding material, if a separate venting member is provided, the configuration is complicated and the cost is increased. .

  In addition, in a structure that vents the gas contained in the thermoplastic injection molding material by installing a gas vent in the material flow path of the thermoplastic injection molding material or by installing an air vent at the filling end of the molded product shape (cavity). A gas such as air or gas is extruded from an air vent by a filled thermoplastic injection molding material. Since this air vent is formed by a gap between components of an injection nozzle, the thermoplastic injection molding material is If it enters, post-finishing will be required due to the occurrence of burrs, surplus shapes, etc., leading to inefficiency in productivity and inducing corrosion in the mold, shortening the mold maintenance cycle. Furthermore, the gas contained in the filled thermoplastic injection molding material is compressed between the outer wall of the large diameter screw head and the inner wall of the small diameter injection nozzle. However, there is also a part that is driven to the inner wall side of the injection nozzle with a small diameter, but eventually it is caught in the mold from the injection nozzle, and as a result, the removal of gas is entrusted only from the air vent, Gas removal was insufficient and improvements were desired.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to remove gas contained in a thermoplastic injection molding material having a simple structure at a low cost and efficiently before the thermoplastic injection molding material is molded (inhibition of gas entrainment). An object of the present invention is to provide a gas entrainment suppressing nozzle structure for a molding machine that can be used.

The present invention relates to a gas entrainment suppression nozzle nozzle structure of a molding machine in which a thermoplastic injection molding material is melted and fluidized, injected into a mold from an injection nozzle, and cooled and solidified in the mold. A flow path for material for circulating the molten thermoplastic injection molding material is formed, and the flow path for material is a flow path for inflow having a predetermined inner diameter on the side into which the thermoplastic injection molding material flows. A taper-shaped tapered flow path communicating with the flow path, and an inner diameter smaller than the inner diameter of the inflow flow path communicating with the tapered flow path, and injecting the thermoplastic injection molding material into the mold The injection nozzle is provided with a porous part for extracting the gas contained in the thermoplastic injection molding material to the outside at a position corresponding to the tapered flow path. To do.
Further, in the gas entrainment suppressing nozzle structure of the molding machine that flows the thermoplastic injection molding material and extrudes it as a molded product from the extrusion hole of the molding nozzle, the molding nozzle is included in the thermoplastic injection molding material around the extrusion hole. It is characterized by providing a porous part for extracting gas to the outside.

  The gas entrainment suppressing nozzle structure of the molding machine according to the present invention efficiently removes the gas contained in the thermoplastic injection molding material melted by the nozzle before the thermoplastic injection molding material is molded, and has a simple structure. Cost can be lowered.

FIG. 1 is a cross-sectional view of a tip of an injection nozzle. Example 1 FIG. 2 is a front view of the tip of the injection nozzle. Example 1 FIG. 3 is a sectional view of the main body of the injection nozzle. Example 1 FIG. 4 is a front view of the main body of the injection nozzle. Example 1 FIG. 5 is a sectional view of the entire injection nozzle at the time of injection of the thermoplastic injection molding material. Example 1 FIG. 6 is a schematic configuration diagram of a thermoplastic injection molding machine. Example 1 FIG. 7 is an explanatory view at the time of plasticizing the thermoplastic injection molding material. Example 1 FIG. 8 is an explanatory view at the time of injection of the thermoplastic injection molding material. Example 1 FIG. 9 is an explanatory view when the injection of the thermoplastic injection molding material is completed. Example 1 FIG. 10 is an explanatory view when the injection screw moves backward. Example 1 FIG. 11 is an explanatory view when the mold is opened and the molded product is taken out. Example 1 FIG. 12 is a schematic configuration diagram of the extruder. (Example 2) FIG. 13 is a front view of the forming nozzle of the extruder. (Example 2) FIG. 14 is a sectional view in which the extrusion hole of the forming nozzle is tapered. (Example 2)

  The purpose of this invention is to make the nozzle porous so as to efficiently remove the gas contained in the thermoplastic injection molding material having a simple structure and low cost before the thermoplastic injection molding material is molded. This is realized by providing a section.

1 to 11 show Embodiment 1 of the present invention.
In FIG. 6, reference numeral 1 denotes a thermoplastic injection molding machine as a molding machine. The thermoplastic injection molding machine 1 includes a supply zone 2, a compression zone 3, and a metering zone 4, and also includes a plasticizing device 5 that constitutes the supply zone 2, and a compression zone 3 and a metering zone 4. The injection device 6, the mold clamping device 7, the power control unit 8, and the electric control unit 9 are arranged. The mold 10 is arranged in the mold clamping device 7, and the thermoplastic injection molding material (resin) Is melted (plasticized) and fluidized and injected and filled (cast) into a cavity (not shown) in the mold 10 from the injection device 6, and cooled and solidified in the mold 10 to produce a molded product. is there.

  The plasticizing apparatus 5 melts a necessary solid thermoplastic injection molding material. A hopper 11 into which a pellet-shaped thermoplastic injection molding material is charged, and a pellet-shaped thermoplastic injection molding material in the hopper 11. And a cylindrical heating cylinder (heating cylinder) 12 that melts upon receiving the gas. The cylinder 12 includes a cylinder chamber 13 inside, and a band heater 14 serving as a heat source for melting the internal pellet-like thermoplastic injection molding material is wound around the outer peripheral surface. Thermoplastic injection molding materials are produced by adding various necessary materials such as reinforcing agents and fillers to the base resin, melting when heated from the solid state, and becoming solid when cooled from this molten state There is.

As shown in FIG. 6, the injection device 6 is arranged in the cylinder chamber 13 of the cylinder 12 to measure the molten injection molding material 15 and the injection screw 15 for conveying the molten thermoplastic injection molding material. And an injection nozzle 16 for injecting.
The injection screw 15 includes a screw head 17 at the tip, and for example, a thermoplastic injection molding material melted by a hydraulic or electric drive unit 18 is agitated and plasticized, and is also melted by rotating and moving forward. The plastic injection molding material is pressed and compressed to flow toward the injection nozzle 16 side. The screw head 17 extrudes the molten thermoplastic injection molding material to the injection nozzle 16 side.
The injection nozzle 16 has a main body (cylinder head) 19 attached to the tip of the cylinder 12 so as to face the screw head 17, and a melt that is attached to the main body 19 and enters next during cooling in the mold 10. And a tip 20 that weighs the injected thermoplastic injection molding material and injects it into the mold 10, and prevents deformation of the nozzle touch (connection between the outlet of the chip 20 and the inlet of the mold 10), or thermoplasticity. In order to prevent wear due to filling of the injection molding material, it is made of a material having a required hardness.

  The main body 19 is formed of a steel material, and as shown in FIGS. 3 and 4, a main body side material passage 21 penetrating on the axial center, a hexagonal main body side outer shape portion 22 at an intermediate portion, and the main body outer shape portion 22. Three bolt holes 23, 23, 23 formed radially from the outside, one main body outer spline 24 attached to the end of the cylinder 12, and the other end on the shaft center so that the tip 20 can be inserted. And an inner spline 25 formed in a recess. The bolt hole 23 is provided with a fixing bolt (not shown) for fixing the end of the cylinder 12.

As shown in FIGS. 1 and 2, the tip 20 includes a tip outer spline 26 that fits into the inner spline 25 of the main body 19, a hexagonal tip side outer portion 27 at an intermediate portion, and a tapered tip gradient portion having an angle θ. 28.
Further, the chip 20 is formed with a material flow path 29 for circulating a molten thermoplastic injection molding material that penetrates on the axis and communicates with the main body side material passage 21.
The material flow path 29 is connected to the inflow path 30 having a predetermined inner diameter D1 on the side into which the molten thermoplastic injection molding material flows, and the inner wall surface 31 communicates with the inflow path 30 at an angle α. A tapered conical tapered channel 32 with a tapered surface and a molten thermoplastic injection molding material formed in an inner diameter D2 communicating with the tapered channel 32 and having an inner diameter D2 smaller than the inner diameter D1 of the inflow channel 30. 10 and an injection flow path 33 for injecting the gas into the gas. This injection flow path 33 serves as an outlet (connection port) to the mold 10, and the tip is connected to the inlet of the mold 10 (nozzle touch).

The chip 20 is formed by employing, for example, a metal stereolithography combined processing method.
In this metal stereolithography composite processing method, a metal powder is laminated to a predetermined thickness, laser is irradiated to sinter, a new metal powder is laminated on the sintered metal layer to a predetermined thickness, It is an innovative manufacturing method that can sinter by irradiating a laser and produce breathable metal parts by repeating high-speed cutting with a small diameter end mill multiple times.
The tip gradient portion 28 of the tip 20 has a porous portion (venting portion: Pocera hole) for removing a gas (gas) contained in the thermoplastic injection molding material melted at a location corresponding to the internal tapered flow path 32. ) 34 is provided.
The gas contained in the molten thermoplastic injection molding material is mainly generated from the chemical components contained in the base resin, which causes defects in the molded product and induces corrosion of the mold. .

Since the porous portion 34 is difficult to be evenly arranged on the already formed chip by simple drilling, for example, the tip gradient portion 28 is formed at a position corresponding to the tapered flow path 32 by a metal stereolithography combined processing method. Is formed to have a width W around the entire circumference of the tip gradient portion 28.
The porous portion 34 does not allow the molten thermoplastic injection molding material to pass through, but has a property of allowing the gas contained in the thermoplastic injection molding material to pass therethrough. On the other hand, the portion other than the porous portion 34 of the chip 20 has such a property that not only the molten thermoplastic injection molding material itself but also gas contained in the molten thermoplastic injection molding material does not pass through. . That is, in the chip 20, the air permeability of the porous portion 34 is higher than the air permeability of other portions.
In the porous portion 34, a tapered flow passage is used to vent a large amount of gas on the tip side (injection flow passage 33 side) of the tip gradient portion 28 that is the largest pressure of the molten thermoplastic injection molding material. It is also possible to gradually increase the air permeability from the upstream side (screw head 17 side) of 32 to the downstream side (injection flow path 33 side).
In providing the porous portion 34 in the chip 20, first, the entire chip 20 is formed, and a hole corresponding to the porous portion 34 is provided in the chip 20 at a desired location. It is also possible to provide the porous portion 34 by a metal stereolithography composite processing method or other methods.

  The mold clamping device 7 includes a pair of mold holding portions 35 and 35, and closes the one-side mold 10-1 and the other-side mold 10-2 as the mold 10 and clamps them at high pressure, and thermoplastic injection molding. The one side mold 10-1 and the other side mold 10-2 are prevented from opening by the filling pressure of the material, the filled thermoplastic injection molding material is cooled and shaped, and the molded product is taken out. Therefore, the one side mold 10-1 and the other side mold 10-2 are separated.

  The power control unit 8 uses a hydraulic pump or an electric motor as a drive source, and operates each of the above-described devices by this drive source, and the shape and shape of the thermoplastic injection molding material entering the mold 10 depending on pressure and speed. For example, in the plasticizing apparatus 5, as shown in FIG. 8, when the thermoplastic injection molding material is injected, the injection screw 15 is moved forward while rotating, and after the completion of the injection, it is shown in FIG. Thus, the injection screw 15 is moved backward.

  The electric control unit 9 operates according to a program for the operation of each of the above devices. Depending on the molding conditions for shaping the molded product, adjustment of pressure level, speed adjustment, position adjustment, etc. To control each device so as to meet the molding conditions for shaping the molded product.

Next, the effect | action of this Example 1 is demonstrated based on FIGS.
In the production of a molded article by the thermoplastic injection molding machine 1, first, as shown in FIG. 7, when a pellet-shaped thermoplastic injection molding material is introduced from the hopper 11, the thermoplastic injection molding material is heated in the cylinder 12. And melted (plasticization).
As shown in FIG. 8, when the injection screw 15 moves forward while rotating, the molten thermoplastic injection molding material is pressed by the screw head 17 of the injection screw 15 and injected from the injection nozzle 16 to the mold 10. The
At this time, the molten thermoplastic injection molding material in the tapered flow path 32 immediately before filling the mold 10 is pressed by the screw head 17 of the injection screw 15 to form the tapered flow path 32 and the taper of the tip gradient portion 28. It is squeezed by the inner wall surface 31 of the tapered flow path 32 and retains as a large pressure.
The molten thermoplastic injection molding material is compressed by a large pressure between the outer wall portion of the large diameter screw head 16 and the inner wall surface 31 of the tapered flow path 32 of the tip gradient portion 28 of the small diameter injection nozzle 16. As shown in FIG. 5, the gas (gas) that is repelled to the inner wall 31 side of the tapered flow path 32 of the tip gradient portion 28 is passed through the porous portion 34 to the outside (atmosphere) of the injection nozzle 16. (Shown by a two-dot chain line in FIG. 5). However, at this time, the porous portion 34 passes only the gas, but does not allow the molten thermoplastic injection molding material itself to pass.
After that, as shown in FIG. 9, when the injection into the mold 10 is completed, the injection screw 15 is moved backward as shown in FIG. 10, and the mold is opened as shown in FIG. The molded product 36 is taken out.

  As a result, when the molten plastic injection material is injected into the mold 10, the gas contained in the thermoplastic injection molding material is greatly removed immediately before the molten thermoplastic injection molding material is injected and filled into the mold 10. As a result (inhibition of gas entrainment), the occurrence of defects in the molded product can be prevented to improve productivity, and the maintenance cycle of the mold 10 can be lengthened.

12 to 14 show a second embodiment of the present invention.
The features of the second embodiment are as follows. That is, as shown in FIG. 12, an extruder 101 as a molding machine is attached to a cylinder 103 provided with a screw 102 inside, a charging hopper 104 provided in the cylinder 103, and a tip of the cylinder 103. A molding nozzle 105 and a drive unit 106 that drives the screw 102 are provided.
The extruder 101 flows a thermoplastic injection molding material and extrudes it as a molded product from the extrusion hole 107 of the molding nozzle 105.
As shown in FIG. 13, the molding nozzle 105 is provided with a porous portion 108 for extracting gas contained in the thermoplastic injection molding material around the extrusion hole 107.
Since the porous portion 108 has the same properties as the porous portion 34 shown in the first embodiment, detailed description thereof is omitted here.
In the structure of the second embodiment, when the thermoplastic injection molding material is pushed toward the molding nozzle 105 by the screw 102 in the cylinder 103, the gas contained in the thermoplastic injection molding material is released from the porous portion 108. Since it is extracted outside, it is possible to efficiently suppress the gas contained in the molded product extruded from the extrusion hole 107 of the molding nozzle 105.
In the second embodiment, as shown in FIG. 14, it is possible to remove gas more effectively by forming a tapered surface 109 that gradually narrows from the inside to the outside in the extrusion hole 107. is there.

  The gas entrainment suppressing nozzle structure of the molding machine according to the present invention can be applied to other devices.

DESCRIPTION OF SYMBOLS 1 Thermoplastic injection molding machine 5 Plasticization apparatus 6 Injection apparatus 7 Clamping apparatus 8 Power control part 9 Electric control part 10 Mold 12 Cylinder 15 Injection screw 16 Injection nozzle 19 Main body 20 Tip 28 Tip gradient part 29 Material flow path 30 Inflow channel 31 Inner wall surface 32 Tapered channel 33 Injection channel 34 Porous part

Claims (3)

  In a gas entrainment suppression nozzle structure of a molding machine in which a thermoplastic injection molding material is melted and fluidized and injected from an injection nozzle into a mold and cooled and solidified in the mold, the injection nozzle has a molten thermoplastic injection. A material flow path is formed for the flow of the molding material, and the material flow path communicates with the inflow path having a predetermined inner diameter and the inflow path on the side where the thermoplastic injection molding material flows. A tapered tapered channel and an injection channel communicating with the tapered channel and having an inner diameter smaller than the inner diameter of the inflow channel and injecting the thermoplastic injection molding material into the mold; A gas for a molding machine comprising the injection nozzle provided with a porous portion for extracting gas contained in the thermoplastic injection molding material to the outside at a location corresponding to the tapered flow path. Entrainment suppression nozzle structure .   The porous part is provided in a tip at the tip of the injection nozzle, and has a property of allowing gas contained in the thermoplastic injection molding material to pass therethrough but not allowing the thermoplastic injection molding material itself to pass through. The gas entrainment suppressing nozzle structure of the molding machine according to claim 1.   In a gas entrainment suppression nozzle structure of a molding machine that flows a thermoplastic injection molding material and extrudes it as a molded product from an extrusion hole of a molding nozzle, the molding nozzle receives a gas contained in the thermoplastic injection molding material around the extrusion hole. A gas entrainment suppression nozzle structure for a molding machine, comprising a porous portion for extraction to the outside.

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