JP3034721B2 - Injection molding die and injection molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an injection mold and an injection mold.
It relates out molding method, particularly to those that form mirror surface in the molded article by transferring the molten molding material transfer surface formed on the molding surface was injected and filled into the cavity.

[0002]

2. Description of the Related Art Conventionally, a molding surface defining a cavity having a predetermined volume, a transfer surface formed on the molding surface and transferring a mirror surface to a molded product, and a gate having a predetermined area opening on the molding surface are provided. , it is injected and filled through a gate the molten resin into the cavity cooled and the molded article, for example a mirror, lens or injection molding of a plastic optical element such as a prism molded with high precision, are known.

[0003] injection molding of this kind, although the uniformity of high-precision mirror surface and the refractive index in the optical element is required, the sink marks in the mirror required surface accuracy due to shrinkage when the molten resin is solidified There was a problem that it would occur. Therefore, in recent years, various improvements such as an injection molding method, an injection mold, a resin material, and an injection molding machine have been performed. In the molding method, an injection filling compression method for improving transferability of a transfer surface,
In addition, a uniform temperature / pressure control method for alleviating distortion in a molded article has been proposed. In addition, in an injection mold, a mold material and a mold structure that enable uniform cooling and a mold structure that enables pressure control have been proposed. However, it is possible to prevent sink marks by injecting and filling the molten resin at high pressure to improve surface accuracy and to prevent internal distortion by temperature control.However, delicate temperature and pressure control in mass production is difficult. However, it is difficult to maintain a high level of yield due to the deformation and the difference in shrinkage due to the residual internal strain due to the molding.

[0004] In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 3-128218 and Japanese Patent Application Laid-Open No. 3-151
No. 218 or JP-A-3-281213 (hereinafter also referred to as a first conventional example).
There is. In this injection molding die, the molding surface facing the transfer surface is roughened, injection is stopped immediately before completion of filling of the molten resin into the cavity, and the molten resin is cooled and solidified without applying holding pressure to form the molten resin. A sink is generated on the rough surface side due to a difference in adhesion between the transfer surface and the rough surface, thereby preventing a sink from occurring on the mirror surface.

In Japanese Patent Application Laid-Open No. 3-151218, the molding surface facing the transfer surface is roughened, and an overflow portion into which excess molten resin flows is provided outside the cavity, and filling of the overflow portion is started. An injection molding die (hereinafter referred to as a second conventional method) in which injection is stopped at a point in time and solidified by cooling without applying a holding pressure, thereby causing sink marks on the rough surface side due to a difference in adhesion between the molten resin and the transfer surface and the rough surface. (Also referred to as an example). The injection molding die allows the variation of the stop timing and the change of the resin material and the molding condition by the overflow portion.

[0006] An injection mold capable of uniform cooling is described in JP-A-63-286308.

[0007]

However, in such a conventional example, an optical element (for example, a mirror) which requires only one mirror surface in order to roughen the molding surface facing the transfer surface of the mold. Can be formed, but the position and the number of mirror surfaces are limited, and it is impossible to form an optical element such as a lens or a prism. Further, depending on the material constituting the transfer surface and the rough surface and the material of the molten resin, there has been a problem that the adhesive force is reversed and the mirror surface is sinker.

In the first conventional example, it is very difficult to stop the injection immediately before the completion of the filling, and if the timing of the stop is shifted, the adhesion between the transfer surface and the rough surface is reversed and the mirror surface is indented. Or shortage of molten resin. Further, in the second conventional example, it is possible to widen the time range of the timing of stopping the filling of the molten resin,
Since the overflow portion is integrally formed with the molded product, a step of removing the overflow portion is required, which increases the cost. In addition, if the opening area of the gate through which the molten resin flows into the overflow portion is too small, the transfer surface and the rough surface However, there has been a problem that the adhesion force is reversed to cause sink marks on the mirror surface, and if it is too large, the molten resin becomes insufficient.

Here, the mirror surface transfer of the transfer surface to the molded product is performed in a temperature region where the molten resin is solidified. If the internal pressure of the resin in the cavity in the temperature region is high, internal distortion occurs in the molded product and the molding is performed. The mirror surface accuracy of the product is reduced and the refractive index becomes non-uniform. The internal strain of the molded product is determined by the relationship between the pressure P, the specific volume V, and the temperature T of the physical properties of the resin during the cooling process. It is opened to try to reach a specific volume according to its temperature and pressure. However, since the resin is solidified and has a small degree of freedom, internal strain increases. If the resin internal pressure is too high, the mirror surface accuracy is reduced and the refractive index is non-uniform. Further, the resistance at the time of releasing the molded product from the mold is increased, so that the deformation easily occurs.

On the other hand, when the internal pressure of the resin is too low, the transfer of the transfer surface to the molded product is not sufficiently performed, and sink occurs to reduce the mirror surface accuracy. At this time, however, the internal distortion is small because the internal pressure of the resin is so low that the sink occurs. Tend to be. in short,
It is possible to obtain an optical element having a high-precision mirror surface without internal distortion by generating sink marks in places where the optical characteristics are not affected.

Accordingly, the present invention provides a method for generating sink marks outside the mirror surface of a molded product without strict control of the filling amount of the molding material by generating an air pressure difference between the mirror surface portion of the molding material and a predetermined portion. Injection mold and injection molding capable of forming a molded product having a highly accurate mirror surface without internal distortion
The aim is to provide a method .

[0012]

In order to achieve the above object, an invention according to claim 1 is characterized in that a molding surface defining a cavity having a predetermined volume, and at least one or more molding surfaces formed on the molding surface have a mirror surface on a molding. A transfer surface to be transferred, and a gate which is opened on the molding surface and injection-filled with a molten molding material in a cavity,
In the injection molding mold, which is formed by injection-filling a molten molding material into a cavity through a gate and cooling and molding a molded product, the molding material has a predetermined area outside the transfer surface of the molding surface. At least one or more ventilation holes that are open, and at least one or more communication holes that communicate with the ventilation holes and apply a predetermined air pressure to the molding material are provided, and a ventilation is provided with a mirror surface portion corresponding to a mirror surface of the molding material. It is characterized in that a pressure difference is generated between a vent and a vent corresponding to the mouth to cause sink in the vent.

According to a second aspect of the present invention, the vent is provided at a position separated by a predetermined distance from the transfer surface. , And a plurality thereof are provided so as to be distributed within a predetermined range outside the mirror surface. The invention according to claim 4 is characterized in that the communication hole is formed so as to communicate the cavity and the outside of the mold through the vent.

According to a fifth aspect of the present invention, a plurality of the vents are provided, and the communication hole is formed so as to communicate with the plurality of the vents. At least one of the vents is separated from the gate on the molding surface and provided near the position where the molding material finally reaches at the end of injection filling.

According to a seventh aspect of the present invention, the communication hole is formed so as to be connectable to a compression device that feeds air to apply a predetermined air pressure to the ventilation port of the molding material through the ventilation port. It is a feature. Claim 8
The described invention is characterized in that the vent hole and the communication hole are formed on a parting surface so as to be defined when the mold is clamped.

According to a ninth aspect of the present invention, the vent and the communication hole are formed inside the mold so as not to be exposed on the parting surface. Claim 1
0 described invention, the opening width of the vent, 0.001 to
It is characterized by being formed to 0.5 mm. Sa
Further, the invention according to claim 11 provides a cavity having a predetermined volume.
And a molding surface defining at least one or more
A transfer surface for transferring a mirror surface to a formed product,
Injects and fills the opening with molten molding material in the cavity
A gate and an opening with a predetermined area outside the transfer surface of the molding surface
At least one or more air vents, and
At least one or more for providing a predetermined air pressure to the shaped material
Preparation for preparing a pair of injection molds having communication holes
Process and a filling process for injecting and filling a molding material from the gate
And communicating with the vent of the molding material corresponding to the vent.
The injection filling is performed while applying a predetermined air pressure through the hole.
And a cooling step of cooling the molding material.
Between the mirror surface corresponding to
Generating a pressure difference to cause sinkage in the vent.
Features.

[0017]

According to the first aspect of the present invention, there is provided a vent having a predetermined area outside the transfer surface of the molding surface defining the cavity of the mold, and a communication hole communicating with the vent to apply a predetermined air pressure to the molding material. Are formed at least one each. Then, when molding the molded product, a predetermined air pressure is applied to the ventilation port corresponding to the ventilation port of the molding material injected and filled into the cavity of the mold by the communication hole. Therefore, no air pressure is applied to the mirror surface portion corresponding to the mirror surface of the molding material, so that a pressure difference is generated between the mirror surface portion and the vent.
Also, during the cooling process, the cooling effect of the vent is reduced due to contact with air, and the solidification is delayed.

Here, sink is caused by separation of the molding material from the molding surface. However, as long as the molding material does not solidify slowly, the resin internal pressure is low, or air or the like does not enter between the surfaces. Since the air layer must be separated against the negative pressure, the air layer is likely to be generated at a location where the air layer exists and a location where the vacuum is easily broken. Therefore, the solidification of the vent is delayed and a predetermined air pressure is applied, so that the sink is selectively generated in the vent and the transfer surface of the mold is high without causing sink in the mirror surface. Transferred to precision.

According to the second aspect of the present invention, the vent is provided at a position separated from the transfer surface by a predetermined distance. Therefore, the influence of sink marks on the mirror surface is prevented. According to the third aspect of the present invention, a plurality of vents are provided so as to be distributed within a predetermined range outside the transfer surface. Therefore,
The locations where sink marks occur are dispersed and the influence of sink marks is reduced.

Further, in the invention according to the fourth aspect, the communication hole is formed so as to communicate the cavity and the outside of the mold through the vent. Therefore, a pressure difference between the mirror surface portion of the molding material and the outside air is given to the vent portion, and the transfer surface of the mold is transferred with high accuracy. According to the fifth aspect of the present invention, a plurality of vents are provided, and a communication hole formed to communicate each of the vents is provided. Therefore, the air in the cavity at the time of injection filling of the molding material is compressed and filled into the communication hole, and the air pressure is applied to the vent of the molding material, so that the pressure difference between the mirror surface of the molding material and the vent is increased. Is efficiently generated.

According to the sixth aspect of the present invention, at least one or more vents are provided on the molding surface separated from the gate to which the molding material reaches at the end of injection filling. Therefore, the air in the cavity is compressed and filled into the communication hole without remaining, and a pressure difference is more efficiently generated between the mirror surface portion of the molding material and the vent portion. In the invention according to claim 7, the communication hole is formed so as to be connectable to the compression device. Accordingly, a predetermined air pressure can be applied to the vent of the molding material through the communication hole and the vent by the compression device, and a pressure difference is arbitrarily generated between the mirror surface of the molding material and the vent. You.

In the invention according to claim 8, the vent and the communication hole are formed in the parting surface. Therefore, even if the molding material enters a part of the vent, the mold is easily released. According to the ninth aspect of the present invention, the ventilation hole and the communication hole are formed inside the mold so as not to be exposed on the parting surface. Therefore, the airtightness does not decrease on the parting surface, and the degree of freedom of the arrangement of the ventilation holes and the communication holes is improved.

According to the tenth aspect of the present invention, the vent is formed to have an opening width of 0.001 to 0.5 mm. Therefore, intrusion of the molten molding material into the inside of the ventilation hole is prevented. Further, according to the eleventh aspect of the present invention, out of the transfer surface
Ventilation opening and molding material communicating with the ventilation opening
Of injection molding die with communication hole to apply air pressure to
Injection molding material into the cavity and vent
A predetermined hole is formed by a communication hole at the vent of the molding material corresponding to
Since the molding material is cooled while applying air pressure,
No air pressure is applied to the mirror surface corresponding to the mirror surface,
During the cooling process, a pressure difference is created between the surface and the vent
Because the cooling effect of the vent is in contact with air
Lowering and slowing down solidification. Therefore, claim 1
In the same way as in the invention of the first aspect, the sink is selectively generated in the vent and the mirror is formed.
Mold transfer surface with high precision without sink marks on the surface
Transcribed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 show an injection mold and an injection mold according to the present invention.
FIG. 1A is a view showing an entire configuration of a first embodiment of a molding method , and FIG. 1A is a plan view of a parting surface of an injection molding die ;
2 (b) is a sectional view taken along line AA, and FIG. 2 (c) is a sectional view taken along line BB. FIGS. 2 (a) to 2 (c) illustrate the flow of the molten resin and the air in the cavity during the injection and filling. FIG. In this embodiment, claims 1, 3, 5, 6, 8, 1
This corresponds to the inventions described in 0 and 11 .

First, the structure of the injection mold will be described. In FIG. 1, reference numeral 10 denotes an injection molding die.
Consists of a pair of mold bases 11 and 12,
A nest 14, 15 having a mirror-finished transfer surface 13 for transferring a mirror surface to a molded product is mounted inside, and mold bases (hereinafter, also simply referred to as bases) 11, 12 have side surfaces 11a,
A molding surface defining a cavity 16 having a predetermined volume is formed by the transfer surface 13 and the transfer surface 13.

The injection mold 10 is used as a base when the mold is clamped.
Between the parting surfaces 11b and 12b of the parts 11 and 12, the resin (molding material) R which communicates with the outside and opens at a predetermined area on the side surface 11a is injected into the cavity 16 by a known injection filling machine (not shown). A gate 17 to be filled, a plurality of vents 18 opening to the side surface 11a with a predetermined area, and a bypass (communication hole) 19 having a predetermined volume formed to communicate the plurality of vents 18 are defined. Parting surface 11 of base 11
A groove is engraved on the b side. This vent 18 is made of molten resin R
Depth (t) 0.005-0.5mm, width (l) to prevent penetration
Is formed so as to be evenly distributed on the side of the transfer surface 13, and a ventilation hole 18a is formed at a position separated from and facing the gate 17. Also,
When the cavity 19 is filled with the molten resin R and the internal air is compressed and filled therein, the bypass 19 is provided with the vents 18 and 18a.
A predetermined air pressure (compression pressure) is applied to the molten resin R via the.

Next, the operation of the injection molding method will be described with reference to FIG.
Will be described. First, prepare the injection mold 10 (preparation
Step), the gate of the resin R which is melted from the injection filling machine 17
Injected via the starts filling into the cavity 16. This
At this time, as shown in FIG. 2A, the air in the cavity 16 is compressed toward the ventilation port 18a and the ventilation ports 18, 18a
And is filled into the bypass 19 and compressed.

Then, the molten resin R having substantially the same volume as the volume of the cavity 16 is filled in the cavity 16 and the injection of the injection filling machine is stopped (filling step). At this time, FIG.
The air is compressed and filled into the bypass 19 as shown in FIG.
The air contacts the resin portion (vent portion) r 'corresponding to the vents 18 and 18a of the resin R, and the vents 18 and 18a
A predetermined air pressure compressed and filled in the bypass 19 is uniformly applied to the resin portion (mirror surface portion) r corresponding to the molding surface including the transfer surface 13 of the resin R, so that no air pressure is applied to the resin portion r. A pressure difference is generated between the part r and the resin part r ′.

Next, the mold 10 is cooled at a predetermined cooling rate.
Te cooling the resin R in the cavity 16. (Cooling step).
At this time, since the resin portion r 'is in contact with the air and has a lower cooling effect than the resin portion r, the cooling rate is slowed and the solidification is slowed. Then, when the molten resin R starts to be solidified and contracts, shrinkage occurs in either the resin part r or the resin part r ′. However, in order to separate the resin part r from the molding surface, a vacuum in the space is required. While the resin part r 'must be separated against the pressure, the air pressure is
The air is easily applied by the air, and the solidification is slowed, so that the resin portion r 'is sink-marked.

Therefore, the transfer surface 13 is transferred with high precision without causing sink marks on the resin portion r, and a mirror surface is formed. In addition, since the resin R has substantially the same capacity as the capacity of the cavity 16, the internal pressure of the resin is not increased, and no distortion occurs inside the resin R. Further, the sink is selectively performed by the resin portion r '.
Therefore, management of control of the injection filling amount of the resin R can be simplified.

As described above, in the present embodiment, when the molten resin R is injected and filled in the cavity 16, the air in the cavity 16 is compressed and filled in the bypass 19, and the resin port r '
Since air comes into contact with the air at a predetermined pressure via 18a, sink of a predetermined size is generated in the resin portion r '. Therefore,
The sink is prevented from occurring in the resin portion r, and the transfer surface 13 is transferred with high accuracy. In addition, since the sink is selectively generated in the resin portion r ′, the control of the injection filling amount of the resin R can be easily managed, and the occurrence of internal distortion can be prevented. Therefore, for example, when molding an optical element such as a lens, a molded article having a highly accurate mirror surface and a uniform refractive index without internal distortion is molded.

Further, since the vents 18 are distributed at equal intervals on the side surface 11a and are spaced from the gate 17, the vents 18a are formed and the bypasses 19 are formed so as to communicate the vents 18, 18a, respectively. , Air pressure is vent hole 18, 18a
And the sink is generated in the resin portion r '. Therefore, the mirror surface of the resin portion r to which the transfer surface 13 is transferred is not affected.

Further, a vent 1 having an opening width of 0.005 to 0.5 mm
8, 18a and bypass 19 are parting surfaces 11b, 12b
Therefore, the vents 18, 18a and the bypass 19 can be easily formed in the mold 10. Further, the resin R is prevented from entering the ventilation holes 18 and 18a. In addition, since the mold can be easily released even if it enters, the molded product is prevented from undercut and biting.

Next, the injection-molding die contact according to Figure 3 the present invention
It is a longitudinal cross-sectional view showing the whole configuration of a second embodiment of the injection molding method and the injection molding method , and this embodiment is claimed in claims 1 to 3, 5, 6, 9 to 11.
It corresponds to the described invention. In this embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 20 denotes an injection molding die, and the injection molding die 20 is formed inside the bases 11 and 12 so that the ventilation port 28 and the bypass (communication hole) 29 are not exposed to the parting surfaces 11b and 12b. . Vent 28 is on the side 11 of the base 11, 12
a, 12a are formed in a predetermined area along the shape of the transfer surface 13 so as to be opened at a predetermined area and separated from the transfer surface 13 at a predetermined interval, and the ventilation hole 28 has a width so that the molten resin does not enter. It is formed to 0.005 to 0.5 mm. Also, bypass 29
Are formed so as to allow each of the ventilation ports 28 to communicate with each other.

In this embodiment, in addition to the functions and effects of the above-described first embodiment, the ventilation port 28 and the communication hole 29
Since it is formed inside the bases 11 and 12 so as not to be exposed to the b and 12b, the airtightness does not decrease between the parting surfaces 11b and 12b. In addition, the ventilation port 28 and the communication hole 29 can be freely arranged in accordance with the molding surface, and the ventilation port 28 is formed so as to be separated from the transfer surface 13 at a predetermined interval. Never give.

Next, the injection mold contact 4 according to the present invention
Is a plan view showing the overall configuration of a third embodiment of the pre-injection molding method, the present embodiment according to claim 1,3,4,8, 10, 11
It corresponds to the described invention. In this embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 30 denotes an injection molding die. The injection molding die 30 has a bypass (communication hole) 39 opened to the outside, and a ventilation port.
The cavity 16 is formed so as to communicate with the outside of the mold via an 18. The injection molding die 30 is configured to generate sink marks in the resin part r 'by allowing outside air (air) to come into contact with the resin part r' through the vent hole 18 at an external pressure. Note that only the base 11 is shown in the figure.

In this embodiment, in addition to the functions and effects of the above-described first embodiment, since only the bypass 39 is opened to the outside, the injection mold 30 can be easily manufactured at low cost. Next, FIG. 5 shows an injection mold and an injection molding method according to the present invention.
Is a plan view showing the overall configuration of a fourth embodiment of the method, this embodiment corresponds to claim 1,3,7,8, 10,11 invention described. In this embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, reference numeral 40 denotes an injection mold,
The injection molding die 40 is formed so that a bypass (communication hole) 49 can be connected to a compression device 44 for feeding air. The injection molding die 40 is connected to the compression device 44 via the vent 18 and the bypass 49.
Air of a predetermined pressure is applied from 44 to cause sink in the resin portion r '. Note that only the base 11 is shown in the figure.

In this embodiment, in addition to the functions and effects of the above-described first embodiment, a predetermined air pressure can be applied to the resin portion r 'through the ventilation port 18 and the bypass 49 by the compression device 44.
The pressure can be adjusted. Therefore, sink marks generated in the resin portion r 'can be adjusted, and a higher quality molded product can be molded .

[0040]

According to the first aspect of the present invention, air is brought into contact with the molding material transferred outside the mirror surface by the transfer surface through the ventilation hole and the communication hole to reduce the cooling rate and to ventilate the predetermined air pressure. Since a predetermined pressure difference is generated between the mirror surface portion of the molding material and the vent portion by applying to the mouth portion, sink marks can be selectively generated in the vent portion, and sink marks can be generated in the mirror surface portion. And the transfer surface of the mold can be transferred with high precision. Also, since sink marks are selectively generated in the vent, the control of the filling amount of the molding material into the cavity can be simplified, and the molded article can be molded without generating internal distortion. As a result, it is possible to provide an injection mold capable of easily molding a molded product having a highly accurate mirror surface without internal distortion.

According to the second aspect of the present invention, since the ventilation port is provided at a position separated from the transfer surface by a predetermined distance, the mirror surface can be formed with high accuracy without the influence of sink on the mirror surface. According to the third aspect of the present invention, since a plurality of ventilation holes are provided so as to be distributed within a predetermined range outside the transfer surface, the location where sink marks occur can be dispersed to reduce the influence of sink marks, and a higher height can be achieved. A mirror surface can be formed with high accuracy.

According to the fourth aspect of the present invention, since the cavity and the outside of the mold communicate with each other through the ventilation hole and the communication hole, the space between the mirror surface portion of the molding material and the ventilation hole portion is kept open. The pressure difference can cause sink marks in the vents, and the transfer surface of the mold can be transferred with high accuracy. In addition, a mold can be easily manufactured. According to the fifth aspect of the present invention, since the communication hole is formed so as to communicate with the plurality of vents, when the molding material is injected and filled, the air in the cavity is compression-filled into the communication hole to fill the molding material. Efficiently generate a predetermined pressure difference between the mirror surface and the vent,
A sink can be generated in the vent. In addition, by forming the volume of the communication hole in consideration of the cavity volume and the molding material so that the air pressure applied to the air vent portion applied through the air vent becomes a predetermined pressure, a higher pressure can be obtained without causing internal distortion. A mirror surface can be formed with high accuracy.

According to the sixth aspect of the present invention, since the ventilation port is provided on the molding surface separated from the gate to which the molding material reaches at the end of injection filling, the air in the cavity can be used without remaining. It is possible to more efficiently generate a pressure difference between the mirror surface portion of the molding material and the vent, and to cause sink in the vent. Further, it is possible to prevent the formation of an air layer between the transfer surface and the molding material, and it is possible to improve the reliability of preventing sinking of the mirror surface portion.

According to the seventh aspect of the present invention, since the communication hole is formed so as to be connectable to the compression device, the compression device can arbitrarily generate an air pressure difference between the mirror surface of the molding material and the vent. In addition, sink marks can be generated in the ventilation holes. In addition, the pressure difference can be easily adjusted, and a mirror surface can be formed with higher accuracy without causing internal distortion.

According to the eighth aspect of the present invention, since the ventilation port and the communication hole are formed on the parting surface, the mold can be easily manufactured. Further, even if the molding material enters a part of the ventilation hole, the molded product can be easily released from the mold, and undercut or biting of the molded product can be prevented. According to the ninth aspect of the present invention, since the air vent and the communication hole are formed inside the mold so as not to be exposed on the parting surface, the airtightness does not decrease on the parting surface. In addition, the degree of freedom in the arrangement of the ventilation holes and the communication holes can be improved.

According to the tenth aspect of the present invention, since the opening width of the vent is formed to be 0.001 to 0.5 mm, it is possible to prevent the molten resin from entering the vent. Burrs can be prevented from occurring in the product. Further, according to the eleventh aspect , the preparation
Injection molding and cooling using the injection mold
The mirror surface transferred by the transfer surface
Air is in contact with the molding material through vents and communication holes.
To reduce the cooling rate and
A predetermined pressure between the mirror surface of the molding material and the vent.
Since a force difference is generated, the same effect as in the first aspect of the present invention is obtained.
As possible out is possible to obtain the results. Therefore, high without internal distortion
Injection molding that can easily mold molded products with accurate mirror surfaces
A method can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of an injection mold and an injection mold according to the present invention, wherein (a) shows the injection mold.
FIG. 2 is a plan view of a parting surface showing the entire configuration of the mold, FIG. 2B is a cross-sectional view taken along line AA, and FIG.

FIGS. 2A and 2B are explanatory views for explaining a molding material and a flow of air in a cavity when a molded article is molded by the injection molding method, wherein FIG.
FIG. 3C is a diagram showing a state at the time of filling completion, and FIG.

FIG. 3 is a longitudinal sectional view showing an entire configuration of a second embodiment of an injection mold and an injection mold according to the present invention.

FIG. 4 is a plan view showing the overall configuration of a third embodiment of the injection mold and the injection mold according to the present invention.

FIG. 5 is a plan view showing an entire configuration of a fourth embodiment of an injection mold and an injection mold according to the present invention.

[Explanation of Signs] 10, 20, 30, 40 Injection Mold 11, 12 Mold Base 13 Transfer Surface 14, 15 Nest 16 Cavity 17 Gate 18, 28 Vent Port 19, 29, 39, 49 Bypass (Communication Hole) ) 44 compression equipment

Continuation of the front page (56) References JP-A-58-3767 (JP, A) JP-A-62-145737 (JP, A) JP-A-3-39218 (JP, A) JP-A-3-236923 (JP) , A) Japanese Utility Model Application 51-54167 (JP, U) Japanese Utility Model Application Hei 3-90924 (JP, U) Japanese Utility Model Application 58-168411 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB Name) B29C 45/26-45/44 B29C 33/00-33/76

Claims (11)

(57) [Claims] 1. A molding surface defining a cavity having a predetermined volume, a transfer surface formed on at least one of the molding surfaces and transferring a mirror surface to a molded product, and a molding opening in the molding surface and being melted in the cavity. A gate for injecting and filling a material, comprising a pair of molds, wherein the molding material melted in the cavity is injected and cooled through the gate and cooled to form a molded product. Outside the transfer surface, at least one or more vents opening in a predetermined area, and at least one or more communication holes communicating with the vents and applying a predetermined air pressure to the molding material are provided. An injection molding die, wherein a pressure difference is generated between a mirror surface portion corresponding to a mirror surface and a vent hole corresponding to a vent to cause sink in the vent. 2. The injection mold according to claim 1, wherein said vent is provided at a position separated from said transfer surface by a predetermined distance. 3. An injection mold according to claim 1, wherein a plurality of said vents are provided so as to be distributed within a predetermined range outside said mirror surface. 4. The injection molding die according to claim 1, wherein the communication hole is formed so as to communicate the cavity and the outside of the die through the vent. 5. The injection mold according to claim 1, wherein a plurality of said vents are provided, and said communication holes are formed so as to communicate with the plurality of vents. 6. A method according to claim 1, wherein at least one of said vents is
6. The injection molding die according to claim 5, wherein the molding surface is separated from a gate of the molding surface and provided near a position where the molding material finally reaches at the time of completion of injection filling. 7. The communication device according to claim 1, wherein the communication hole is formed so as to be connectable to a compression device that feeds air to apply a predetermined air pressure to the ventilation port of the molding material through the ventilation port. Injection molding die as described. 8. The injection molding die according to claim 1, wherein the vent and the communication hole are formed on a parting surface so as to be defined when the die is clamped. 9. The injection molding die according to claim 1, wherein said vent and the communication hole are formed inside the die so as not to be exposed on the parting surface. 10. The opening width of the vent is 0.001 to 0.001.
2. The injection mold according to claim 1, wherein the injection mold is formed to have a thickness of 0.5 mm. 11. A molding surface defining a cavity of a predetermined volume.
And at least one or more mirrors formed on the molding surface
A transfer surface for transferring a surface, and a cavity opened on the molding surface.
A gate for injecting and filling a molten molding material into the inside;
At least one opening with a predetermined area outside the transfer surface of the shape surface
A predetermined empty space in the molding material in communication with the upper vent.
And at least one or more communication holes for providing air pressure.
A step of preparing a pair of injection molding dies, a filling step of injecting and filling a molding material from the gate , and a communicating hole formed in a vent of the molding material corresponding to the vent.
Molding material injected and filled while applying a predetermined air pressure
And a cooling step of cooling the mirror.
A pressure difference is created between the air vent and the air vent, causing sink marks.
An injection molding method characterized by being produced.