JP2009262362A - Mold for injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a hot runner housing in which a glass bush is joined integrally to the inner surface of a housing bush. <P>SOLUTION: An injection molding mold 4 includes the hot runner housing 30 having the housing bush 52 which surrounds the peripheral surface of a hot runner nozzle 18 and keeps an injection gate part 50 installed on the side of the chip of the hot runner nozzle 18 and the glass bush 54 which is joined integrally to the inner surface of the housing bush 52 and made of a glass material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection mold having a hot runner nozzle for injecting a kneaded molten resin.

  An injection mold using a hot runner nozzle is one in which a resin melted by heating from a hole at the tip of the hot runner nozzle is injected and injected into the mold through a gate, and cooled and solidified to obtain a molded product.

  In this case, since the resin passage of the gate is a small hole or ring-shaped narrow area for cutting the gate, clogging occurs due to cooling of the resin during injection unless the resin is always heated to a predetermined temperature. In some cases, problems such as injection filling may occur.

Also, if the resin is heated too much to reduce the viscosity of the resin and improve injection filling, the resin does not solidify at the gate, causing stringing or problems such as resin burns.
Conventionally, in order to solve this problem, for example, in Patent Document 1, by inserting a nozzle tip having a low thermal conductivity into an opening formed at a tip portion of a hot runner nozzle, the heat on the hot runner side is injected into a mold inlet. A technology that prevents transmission to the side has been proposed.

This is because when the heat on the hot runner nozzle side is transferred to the injection port side of the mold and the mold is heated, resin stringing occurs at the time of mold release, making it difficult to tear the resin properly. It is intended to block heat transfer with the nozzle tip.
JP 2004-25812 A

  However, in Patent Document 1, a nozzle tip made of a low thermal conductivity metal is slidably inserted into the nozzle tip, but the thermal conductivity is not significantly different from that of other mold members. Therefore, although there is an effect of suppressing the occurrence of stringing due to some heat insulation effect, there is no effect of reducing the temperature of the resin to be injected or suppressing the occurrence of clogging due to a rapid temperature decrease of the resin.

  In Patent Document 1, since a low thermal conductivity metal (titanium alloy or the like) is used as the nozzle tip, the thermal expansion coefficient is small with respect to the surrounding mold material. It is difficult to fix using the linear expansion coefficient difference.

  Even if it is attempted to fix by means such as welding, thermal deformation occurs, and precise machining becomes difficult. Furthermore, in order to join the nozzle tip having a low thermal conductivity to the nozzle tip without using welding means, a separate part is required. In this case, the number of parts increases and the mold becomes large.

For this reason, it is advantageous if a nozzle tip having a low thermal conductivity can be integrally joined to the hot runner nozzle.
The present invention has been made to solve such a problem, and an object thereof is to provide an injection mold including a hot runner housing in which a glass bush made of a glass material is integrally joined to an inner surface of a housing bush. To do.

In order to achieve the object, the invention according to claim 1
In an injection mold for injecting a kneaded molten resin from a hot runner nozzle,
A housing bushing that surrounds the outer peripheral surface of the hot runner nozzle and is provided with an injection gate on the tip side of the hot runner nozzle;
A hot runner housing having a glass bush made of a glass material integrally joined to the inner surface of the housing bush is provided.

The invention according to claim 2 is the injection mold according to claim 1,
The housing bush is made of a metal member.
The invention according to claim 3 is the injection mold according to claim 1 or 2,
The glass bush has a flow path that guides the molten resin injected from the hot runner nozzle to the injection gate portion.

The invention according to claim 4 is the injection mold according to claim 3,
The flow path is formed by grinding the housing bush.
The invention according to claim 5 is the injection mold according to claim 3,
The flow path is formed substantially simultaneously with the transfer of the housing bush by a mold.

The invention according to claim 6 is the injection mold according to claims 3 to 5,
The flow path is formed on an inclined surface that is inclined with a small diameter toward the injection gate portion.

  According to the present invention, it is possible to obtain an injection mold having a hot runner housing in which a glass bush made of a glass material is integrally joined to the inner surface of the housing bush.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Configuration of injection mold]
FIG. 1 is a diagram showing a configuration of an injection molding apparatus.

  The injection molding apparatus 1 includes an injection unit 2 and an injection mold 4. The injection unit 2 plasticizes the resin and performs transfer, kneading, melting and the like to inject a predetermined amount into the injection mold 4. The injection mold 4 is for molding the injection-filled molten resin into a desired shape, and is opened and closed in a mold opening / closing direction (AA direction) by a mold clamping mechanism (not shown).

  The injection unit 2 has a hopper 6 and a unit body 8. In the hopper 6, granular resin 10 (for example, polycarbonate) is accommodated in a kneaded state. The unit body 8 has a horizontal hole 12 extending in the mold opening / closing direction (AA direction) along the mold center axis, and a vertical hole 14 extending in a direction orthogonal to the horizontal hole 12 (vertical direction). And are formed.

  One end of the vertical hole 14 communicates with the hopper 6 and the other end communicates with a storage chamber 15 (described later) formed in a part of the horizontal hole 12. The resin 10 from the hopper 6 is movable toward the vertical hole 14 extending in the vertical direction by gravity.

  The vertical hole 14 contains a plasticizing screw 13 that can be rotated by a drive device (not shown). A heater (not shown) is disposed around the plasticizing screw 13. The plasticizing screw 13 sends out the resin 10 plasticized by a heater (not shown) toward a storage chamber 15 (described later).

  The lateral hole 12 is provided with a storage chamber 15 for the plasticized resin 10 in the middle in the longitudinal direction. The storage chamber 15 communicates with the discharge side of the resin 10 by the plasticizing screw 13. A plunger 16 is slidably provided on one side of the lateral hole 12 with the storage chamber 15 interposed therebetween. Further, a hot runner nozzle 18 is attached to the other side of the lateral hole 12.

  The hot runner nozzle 18 is formed with a nozzle hole 22 through which the resin 10 is led out along its central axis. In addition, a heater 20 is disposed around the periphery. Thus, the molten resin 10 led out of the nozzle hole 22 is heated to a predetermined temperature by the heater 20 and injected from the tip.

  The injection molding die 4 has a fixed side mold plate 24 and a movable side mold plate 26 which are arranged to face each other across the parting line PL. The fixed-side template 24 is fixed to the above-described unit body 8 via the heat insulating plate 28.

  The fixed-side template 24 is provided with a hot runner housing 30 so as to surround the tip end side of the hot runner nozzle 18. The hot runner housing 30 is arranged coaxially with the hot runner nozzle 18. The details of the hot runner housing 30 will be described later. Further, around the hot runner housing 30, fixed molds 32 (two in the figure) are arranged substantially symmetrically.

  A center piece 34 is arranged on the movable side mold plate 26 coaxially with the hot runner nozzle 18. One end of the center piece 34 faces the parting line PL, and the other end protrudes and is fixed to the plate 36. In addition, around the center piece 34, movable molds 38 (two in the drawing) are arranged substantially symmetrically.

  The movable mold 38 is disposed to face the fixed mold 32. Further, eject pins 40 are arranged approximately symmetrically around the inner diameter side of the movable piece 38 of the center piece 34. One end of the eject pin 40 faces the parting line PL, and the other end protrudes and is fixed to the plate 36.

A cavity 42 (two in the figure) is formed between the fixed mold 32 and the movable mold 38 with the parting line PL interposed therebetween. The cavity 42 communicates with an injection gate portion 50 (see FIG. 2) at the tip of the hot runner housing 30 via a gate 44 and a runner 46.
[Configuration of Hot Runner Housing 30]
Next, the configuration of the hot runner housing 30 will be described with reference to FIG.

  The hot runner housing 30 includes a housing bush 52 made of a metal such as stainless steel (SUS) and a glass bush 54 made of a glass material. The housing bush 52 and the glass bush 54 are assembled together.

  The housing bush 52 surrounds the outer peripheral surface of the hot runner nozzle 18, and an injection gate portion 50 is provided on the front end side of the hot runner nozzle 18. The injection gate portion 50 is provided on a bottom portion 53 on one side of the housing bush 52 in the resin injection direction. Further, a flange portion 48 is provided on the other side (opening 55 side) in the resin injection direction.

  The outer diameter of the housing bush 52 is processed with high accuracy so as to be precisely attached to the stationary side template 24. Further, the housing bush 52 is attached to the fixed-side template 24 by the flange portion 48 so that the position can be maintained.

  In the present embodiment, the injection gate portion 50 is formed with a small diameter of 0.7 to 1.0 mm. If the diameter of the injection gate portion 50 is too small, it is difficult to inject the molten resin. Therefore, it is necessary to increase the heating temperature of the resin 10 to improve the fluidity. On the other hand, if the heating temperature of the resin 10 is raised too much, oxidation of the surface of the resin 10 is promoted and there is a possibility that foreign matter or resin burns may occur.

  If the diameter of the injection gate portion 50 is too large, the heating temperature of the resin 10 may be low, but the cooling of the molten resin injected from the injection gate portion 50 is delayed. For this reason, the malfunction which produces stringing at the time of mold release occurs. Therefore, there is a demand for making the diameter of the injection gate portion 50 as small as possible while keeping the heating temperature of the resin 10 low.

  For this reason, in this embodiment, the glass bush 54 having a relatively low thermal conductivity compared to metal is used for the hot runner housing 30. Thereby, the heating temperature of the resin 10 can be kept low while making the injection gate portion 50 small in diameter.

  This is because the glass bush 54 having a low thermal conductivity is used, and the temperature inside does not escape to the injection mold 4 side. For this reason, the temperature of the resin 10 injected from the hot runner nozzle 18 can be kept substantially constant. On the other hand, the resin 10 injected from the glass bush 54 is quickly cooled by the injection mold 4.

  Thereby, even if the heating temperature of the resin 10 is lowered as much as possible, the molten resin can be injected from the injection gate portion 50 having a small diameter. In addition, the molten resin injected from the injection gate portion 50 is rapidly cooled by a low mold temperature and does not cause stringing at the time of mold release.

  Incidentally, since the injection pressure of the molten resin from the hot runner nozzle 18 acts on the hot runner housing 30, it is necessary to reinforce the strength of the glass bush 54. Therefore, in this embodiment, the housing bush 52 is formed in a substantially bottomed cylindrical shape, and the injection gate portion 50 is formed in the bottom portion 53 thereof. That is, the strength of the glass bush 54 is reinforced at the bottom 53 of the housing bush 52.

The material of the housing bush 52 is stainless steel (SUS) or prehardened steel (NUK material).
The glass bush 54 is integrally joined to the inner surface of the housing bush 52. As shown in FIG. 2, the glass bushing 54 has a flow path 56 that guides the molten resin injected from the tip of the hot runner nozzle 18 to the injection gate 50.

  In the present embodiment, the flow path 56 has a conical surface 54a that is inclined so as to have a small diameter toward the injection gate portion 50, and a cylindrical surface 54b that follows the conical surface 54a. And the front-end | tip part of the hot runner nozzle 18 is fitted by this cylindrical surface 54b.

  2 shows a state in which a predetermined gap is formed between the tip of the hot runner nozzle 18 and the cylindrical surface 54b of the glass bush 54. However, this gap is not necessarily required.

  For example, if there is no gap, the resin injected from the hot runner nozzle 18 can be directly injected from the injection gate 50 to the runner 46. However, if there is no gap, the tip of the hot runner nozzle 18 comes into contact with the inner surface of the glass bush 54. In this case, the glass bush 54 may be damaged.

  In addition, since the glass bush 54 consists of glass materials, it is easy to chip. For this reason, in order to form the flow path 56, it is preferable to use means by grinding using a grindstone or the like, or transfer using a mold.

Next, a method for manufacturing the hot runner housing 30 will be described.
[Method for Manufacturing Hot Runner Housing 30]
(Manufacturing method 1)
3A to 3E show the manufacturing process of the hot runner housing 30.

  3A, the housing bush 52 is placed on a pedestal (not shown) with the opening 53 at one end facing upward. Next, a thin disk-shaped first glass member 58 is inserted from the opening 55. Further, the cylindrical second glass member 60 is inserted from the opening 55. These first and second glass members 58 and 60 have different thermal characteristics. That is, the melting temperature of the first glass member 58 is lower than the melting temperature of the second glass member 60.

  For example, the yield point (At point) of the first glass member 58 is approximately 470 ° C. The transition point (Tg point) of the second glass member 60 is high and is approximately 550 ° C. The first glass member 58 is melted by heating and serves to integrally join the bottom 53 of the housing bushing 52 and the second glass member 60.

  Next, as shown in FIG. 3B, the first and second glass members 58 and 60 are sequentially inserted into the inner surface of the housing bush 52. In this state, the whole including the housing bush 52 is heated to approximately 600 ° C. Next, the second glass member 60 is pressed at a predetermined pressure from above the second glass member 60 using the press die 92. The details of the joining apparatus 70 provided with the press die 92 will be described later with reference to FIG.

  At this time, the first glass member 58 is heated to 600 ° C. and becomes fluid. Then, the molten first glass member 58 goes around between the inner surface of the housing bush 52 and the side surface of the second glass member 60. Thus, the bottom 53 of the housing bush 52 and the second glass member 60 are integrally joined. In this case, since the second glass member 60 has a high melting temperature, it maintains the original shape.

  In the present embodiment, the case where the first glass member 58 wraps around and joins between the inner surface of the housing bush 52 and the side surface of the second glass member 60 has been described, but the present invention is not limited thereto. For example, the first glass member 58 may not wrap around the side surface, and the bottom 53 of the housing bush 52 and the bottom of the second glass member 60 may be joined.

  Thus, as shown in FIG. 3C, the housing bush 52 and the second glass member 60 are joined and cooled, and the press die 92 is retracted. Thereby, the housing bush 52 and the 2nd glass member 60 are joined integrally.

  Next, as shown in FIG. 3D, the second glass member 60 is ground using a grinding wheel 62. Since the second glass member 60 is easily chipped, it is carefully processed so as not to give an impact.

  Thus, as shown in FIG. 3E, the second glass member 60 is ground into a desired shape to form a glass bush 54. At this time, the conical surface 54a of the glass bush 54 is a surface through which the injected resin flows, and is finished to a mirror surface. Moreover, since the cylindrical surface 54b is a surface to which the hot runner nozzle 18 is fitted, it is preferably ground to a mirror surface.

  Finally, a small injection gate portion 50 is formed at the bottom 53 of the housing bush 52 to complete the hot runner housing 30. The injection gate portion 50 may be formed on the bottom portion 53 of the housing bush 52 before the first and second glass members 58 and 60 are heated and pressurized. Furthermore, although the glass bush 54 has the conical surface 54a in FIG. 3E, it is not restricted to this, For example, it is good also as a hemispherical surface.

According to this manufacturing method, after the glass bush 54 is integrally joined to the housing bush 52, the inner surface is formed by grinding, so that the hot runner housing 30 having a highly accurate dimension can be obtained.
(Manufacturing method 2)
4A to 4E show another manufacturing process of the hot runner housing 30. In this manufacturing method, the inner surface of the glass bush 54 is formed by a forming means using a mold.

In FIG. 4A, the first and second glass members 58 and 60 are inserted from the opening 55 of the housing bush 52 as in the manufacturing method 1.
The first and second glass members 58 and 60 have different thermal characteristics, and the melting temperature of the first glass member 58 is lower than the melting temperature of the second glass member 60.

  Next, as shown in FIG. 4B, first and second glass members 58 and 60 are inserted into the housing bush 52 in order. In this state, the whole including the housing bush 52 is heated to approximately 600 ° C. Next, the second glass member 60 is pressed with a predetermined pressure from above the second glass member 60 using a press die 93 having a conical tip.

  As a result, as shown in FIG. 4C, the first glass member 58 is melted to join the housing bush 52 and the second glass member 60, and at the same time, the glass having the conical conical surface 54a and the cylindrical surface 54b. A bush 54 is formed.

  4C shows the case where the glass bush 54 has a conical surface 54a, the present invention is not limited to this and may be a hemispherical surface. As a result, the conical surface 54a and the cylindrical surface 54b can be simultaneously formed on the glass bush 54, and these surfaces can be mirror-finished.

  Next, as shown in FIG. 4D, the injection gate portion 50 is processed with a grindstone 64 on the bottom portion 53 of the housing bush 52. The injection gate 50 may be formed in advance on the bottom 53 of the housing bush 52 before the glass material is integrally formed on the housing bush 52.

In this way, as shown in FIG. 4E, the hot runner housing 30 in which the glass bush 54 is integrally joined to the housing bush 52 can be obtained.
According to this manufacturing method, the internal shape of the housing bushing 52 which is difficult to process as compared with the manufacturing method 1 can be transferred once by the forming means. In addition, the surface roughness of the conical surface 54a and the cylindrical surface 54b of the glass bush 54 can be mirror-finished only by transfer. As a result, the resin 10 can be injected at a low temperature. In addition, the time required for manufacturing can be greatly reduced.
(Configuration of joining device)
FIG. 5 is a diagram illustrating a configuration of the joining device 70.

  The joining device 70 includes a lower base 72 and an upper base 73, and the lower base 72 and the upper base 73 are connected by two slide shafts 74. The two slide shafts 74 are connected to each other via a slide bush 75a and a slide bush 76a by a press shaft base 75 provided at the upper portion and a heating furnace base 76 provided at the lower portion.

A pedestal 77 for placing the housing bushing 52 is provided at the center of the upper surface of the lower base 72.
The press shaft base 75 is connected to a press cylinder 82 attached to the upper base 73 via a floating joint 81 at the center of the upper surface thereof. A press shaft 83 is attached to the center of the lower surface of the press shaft base 75. The press shaft 83 can press the second glass member 60 by moving the press die 92 (93) downward in the drawing.

  On the other hand, the heating furnace base 76 is provided with a reflector 85 to which a cylindrical glass tube 84 and a lamp heater 86 are attached. Thus, the molding chamber 88 is defined in the glass tube 84. Further, a heating furnace lid 87 having a hole 87a in which a press shaft 83 is slidable is formed at the center of the molding chamber 88. The heating furnace lid 87 has a structure that does not let the heat in the molding chamber 88 escape.

  The molding chamber 88 has a structure that can replace the oxidizing atmosphere with a non-oxidizing atmosphere. Further, the fitting portion between the heating furnace lid 87 and the press shaft 83 is provided with a seal (not shown) capable of maintaining internal airtightness.

  As described above, after the forming chamber 88 is purged with nitrogen, it is heated to 600 ° C. and the press cylinder 82 is driven. And it presses by the downward movement of the press die 92 (93). After that, the housing bush 52 and the second glass member 60 are integrally joined by holding at 545 ° C. for a certain time during cooling and then cooling.

According to this embodiment, by molding in a non-oxidizing atmosphere, the housing bush 52 and the glass member 60 can be integrally joined while preventing oxidation.
[Operation of injection mold]
Next, the operation of the injection molding apparatus 1 will be described with reference to FIGS.

FIG. 6 is a diagram showing a weighing process of the resin 10.
In addition, control of a heater not shown, the plasticizing screw 13, the plunger 16, etc. is performed by a control device not shown.

Further, in this measuring step, the fixed side mold plate 24 and the movable side mold plate 26 are clamped with the parting line PL interposed therebetween.
In FIG. 6, when the resin 10 (polycarbonate) in the hopper 6 is supplied to the plasticizing screw 13, the resin 10 is heated and plasticized by a heater (not shown) in the plasticizing screw 13. A predetermined amount of the resin 10 is supplied to the storage chamber 15 by rotating the plasticizing screw 13.

  At this time, the plunger 16 moves by a predetermined stroke in the direction away from the hot runner nozzle 18 (in the direction of arrow B in FIG. 6) due to the resin pressure. The plunger 16 may be moved in advance by a predetermined stroke so that the storage chamber 15 has a desired volume. By detecting the stroke amount of the plunger 16, the volume in the storage chamber 15 can be measured. Thus, the resin 10 injected into the injection mold 4 at one time is measured and stored in the storage chamber 15.

FIG. 7 shows the injection process.
In this injection process, the plunger 16 is moved in the direction close to the hot runner nozzle 18. Further, the resin 10 in the storage chamber 15 is injected from the tip of the hot runner nozzle 18 toward the injection mold 4. At this time, the hot runner nozzle 18 is heated to a temperature of about 300 ° C. by the heater 20. This is to improve the fluidity of the resin 10.

  Then, the molten resin 10 passes through the nozzle hole 22 of the hot runner nozzle 18 and is injected from its tip into the flow path 56 in the hot runner housing 30 (see FIG. 2). As a result, the injected resin 10 is filled into the cavity 42 from the injection gate portion 50 through the runner 46 and the gate 44.

After the filling, a predetermined holding pressure is applied to the resin in the cavity 42 by the injection pressure. This is to prevent sink marks or the like from occurring in the molded product.
According to the present embodiment, the resin 10 injected from the tip of the hot runner nozzle 18 is received by the conical surface 54 a on the inner surface of the glass bush 54. Subsequently, it flows along the conical surface 54 a and is guided to the injection gate unit 50.

  Since the conical surface 54a of the glass bush 54 is made of glass having low thermal conductivity, the temperature of the resin 10 injected from the hot runner nozzle 18 (for example, 290 ° C.) does not escape to the injection mold 4 and is not cooled. Fluidity is maintained. At this time, the temperature of the injection mold 4 is heated to about 130 ° C.

  As described above, since the heat of the resin 10 in the glass bush 54 does not escape easily, the temperature of the injected resin 10 is also kept substantially constant, and the fluidity of the resin 10 is ensured. For this reason, the diameter of the injection gate portion 50 can be designed to be as small as possible.

  The resin 10 injected from the injection gate portion 50 into the injection mold 4 is filled into the cavity 42 through the runner 46 and the gate 44. Thus, the resin 10 injected from the injection gate portion 50 is cooled in a short time by the low-temperature injection mold 4 (approximately 130 ° C.).

For this reason, the resin 10 is appropriately cut without causing stringing at the injection gate portion 50 at the time of mold release (pin gate cutting).
FIG. 8 is a view showing a mold release process.

After the injection process, the mold is released through a cooling process after holding pressure.
In this mold release step, the movable side mold plate 26 is released from the fixed side mold plate 24 along the parting line PL by a mold clamping mechanism (not shown). At this time, as described above, the resin 10 is so-called pin gate cut at the injection gate portion 50 without causing stringing. Further, the ejection plate 36 is pushed in the direction C in FIG. 8, the eject pin 40 projects and the molded product 90 is taken out. This molded product 90 is a concave lens as an optical element.

  In the present embodiment, the case where polycarbonate is used as the resin 10 has been described, but the present invention is not limited to this. For example, other thermosetting resins or thermoplastic resins may be used. Also, the molding conditions are not limited to those described above.

  Conventionally, for example, when the resin is injected into the mold cavity 42 from the tip of the hot runner nozzle 18, if the cross-sectional area of the injection gate portion 50 (nozzle hole) is reduced, the temperature of the hot runner nozzle 18 is increased and the resin flows. It was necessary to improve the sex. For this reason, the oxidation of the resin heated to a high temperature is promoted, and this oxidized resin may be mixed into the cavity 42 as a foreign substance.

  On the other hand, if the cross-sectional area of the injection gate portion 50 (nozzle hole) is increased so that the resin can be injected even at a low temperature, the oxidation of the resin is prevented and the generation of foreign matter is eliminated, but the injection gate portion 50 ( There was a risk that threading would occur at the nozzle holes) and take-out errors would occur.

  On the other hand, according to the present embodiment, by using the hot runner housing 30 in which the glass bush 54 is integrally joined to the inner surface of the housing bush 52, the resin 10 injected from the hot runner nozzle 18 is abruptly near the nozzle tip. Therefore, the molten resin 10 can be stably injected from the injection gate portion 50 having a small cross-sectional area even with the resin 10 having a relatively low temperature.

  That is, according to this embodiment, since the glass bush 54 is integrally attached to the inner surface of the housing bush 52, the temperature of the hot runner nozzle 18 can be increased even if the cross-sectional area of the injection gate portion 50 (nozzle hole) is reduced. Without raising, it was possible to prevent the occurrence of stringing at the time of mold release.

It is a figure which shows the structure of an injection molding apparatus. It is a figure which shows the structure of a hot runner housing. It is a figure which shows the manufacturing process of the hot runner housing of the manufacturing method 1. FIG. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the manufacturing process of the hot runner housing of the manufacturing method 2. FIG. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the manufacturing process of a hot runner housing same as the above. It is a figure which shows the structure of a joining apparatus. It is a figure which shows the measurement process of resin in an injection molding apparatus. It is a figure which shows the injection process same as the above. It is a figure which shows a mold release process same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection molding apparatus 2 Injection unit 4 Injection mold 6 Hopper 8 Unit main body 10 Resin 12 Horizontal hole 13 Plasticizing screw 14 Vertical hole 15 Reservoir 16 Plunger 18 Hot runner nozzle 20 Heater 22 Nozzle hole 24 Fixed side mold plate 26 Movable side plate 28 Heat insulating plate 30 Hot runner housing 32 Fixed die 34 Center piece 36 Extrusion plate 38 Movable die 40 Eject pin 42 Cavity 44 Gate 46 Runner 48 Flange portion 50 Injection gate portion 52 Housing bush 53 Bottom portion 54 Glass bush 54a Conical surface 54b Cylindrical surface 56 Channel 58 First glass member 60 Second glass member 62 Grinding wheel 64 Grinding wheel 70 Joining device 72 Lower base 73 Upper base 74 Slide shaft 75 Press shaft base 75a Slide bush 76 Heating furnace base 7 a slide bush 77 pedestal 81 floating joint 82 press cylinders 83 press shaft 84 glass tube 85 a reflector 86 the lamp heater 87 heating furnace lid 87a holes 88 forming chamber 90 moldings 92 press die 93 press dies

Claims (6)

In an injection mold for injecting a kneaded molten resin from a hot runner nozzle,
A housing bushing that surrounds the outer peripheral surface of the hot runner nozzle and is provided with an injection gate on the tip side of the hot runner nozzle;
An injection mold comprising: a hot runner housing having a glass bush made of a glass material integrally joined to an inner surface of the housing bush. The mold for injection molding according to claim 1, wherein the housing bush is made of a metal member. 3. The injection mold according to claim 1, wherein the glass bush has a flow path that guides the molten resin injected from the hot runner nozzle to the injection gate portion. 4. The injection mold according to claim 3, wherein the flow path is formed by grinding the housing bush. The injection mold according to claim 3, wherein the flow path is formed substantially simultaneously with transfer of the housing bush by a mold. The injection mold according to any one of claims 3 to 5, wherein the flow path is formed on an inclined surface inclined in a small diameter toward the injection gate portion.