JP2004284151A - Method and apparatus for molding matter made of synthetic resin having bottomed groove and method for judging depth of bottomed groove - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To judge the depth of a bottomed groove by a simple method in a molding technique for molding matter made of a synthetic resin having the bottomed groove. <P>SOLUTION: A pressure member 20 driven by a cylinder 28 is housed in the slide hole 16, which is provided on the fixed mold 12 of a mold 10, in a slidable manner, and a groove molding member 22, which is movable along the guide groove 141 bored in the fixed mold 12, and a moving member 24 movable along the communication hole 142 bored in the fixed mold 12 are erected on the pressure member 20. After a molten synthetic resin is sealed in a cavity 18, the groove molding member 22 is protruded into the synthetic resin by driving the cylinder 28 to form the bottomed groove 76 becoming a breaking part 74 and it is observed whether the projection formed by a moving member 24, of which the vertical part 242 is set so as to become flush with the inner surface 182 of the cavity 18 when the groove molding member 22 protrudes into the cavity 18 by normal dimension, is present in a groove depth confirming part 78 to judge the depth of the bottomed groove 76. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a molding technique for molding a synthetic resin object having a groove with a bottom, and in particular, by visually checking the synthetic resin object after molding to determine whether or not the depth of the groove with a bottom has a predetermined dimension. The present invention relates to a molding technique that enables determination.
[0002]
[Prior art]
A typical example of a synthetic resin object having a groove with a bottom is an airbag door provided on an instrument panel of an automobile. The airbag door is provided with a groove with a bottom on the back of the instrument panel so that the airbag installed inside the instrument panel is easily broken when deployed. It is molded integrally with the instrument panel so as not to be noticed (so as not to cause sink marks during molding).
A method for manufacturing a synthetic resin object having a groove with a bottom is disclosed as a “pad manufacturing method” described in JP-A-8-268205 (hereinafter referred to as “Patent Document 1”).
[0003]
In the molding die 23 of the pad 10 described in Patent Literature 1, a plurality of fitting holes 25b are formed in a formation portion of a notch portion 14 formed in the planned breaking portion 12, and each fitting hole 25b has a notch. A forming member 26 is slidably disposed. (See “0026” in Patent Document 1 and FIG. 1)
When the pad 10 is molded by using the molding die 23, the molding material M of the pad 10 is first injected into the cavity 23a by clamping. At this time, the notch forming member 26 is kept on standby so as not to protrude from the mold surface 25a of the split mold 25. Then, when the injection of the molding material M is completed, the notch forming member 26 is raised, and thereafter, the split dies 24 and 25 are cooled to cure the molding material M. When the molding material M is cured, the mold is opened and released, and the production of the pad 10 is completed. (See “0028” to “0030” of Patent Document 1 and FIG. 1)
[0004]
The thickness t1 of the notch portion 14 is set such that no sink marks or the like of the breakable portion 12 or the notch portion 14 occur on the outer peripheral surface side of the ceiling wall portion 11 and the airbag 2 can be broken when inflated. The thickness t0 of the general part 13 other than the notch part 14 of the part to be broken 12 is about 0.8 to 2.0 mm. (See “0021” in Patent Document 1)
[0005]
Also, Japanese Patent Application Laid-Open No. 63-302013 (hereinafter referred to as “Patent Document 2”) discloses that when the block 9 is advanced into the cavity space 4, the resin 25 injected into the cavity space 4 is excessive. The closing bar 40 is interlocked with the block 9 to form the resin escape space 26 so that the excess resin 25 is discharged to the resin escape space 26 so as not to be filled. A "method and apparatus for injection molding of a partially thin resin molded article" is disclosed (see FIGS. 4 and 5 of Patent Document 2).
[0006]
[Patent Document 1]
JP-A-8-268205 [Patent Document 2]
JP-A-63-302013
[Problems to be solved by the invention]
By the way, in Patent Document 1, since the fitting hole 25b is opened in the cavity 23a of the molding die 23, the molten molding material M is fitted as shown in the examples of FIGS. There is a case where the molding is completed before the notch forming member 26 is not sufficiently lifted by being engaged between the mating hole 25b and the notch forming member 26, and in this case, the thickness t1 of the notch portion 14 ("T0" in FIG. 10). Is formed thicker than a predetermined thickness, which has a problem that the opening of the airbag door is affected when the airbag is deployed.
However, it is not easy to measure the thickness t1 of the notch portion 14 easily and accurately after the molding because the groove of the notch portion 14 is small.
[0008]
Therefore, an object of the present invention is to provide a technique capable of molding a synthetic resin object capable of determining the depth of a bottomed groove by a simple method in order to solve such a problem.
[0009]
[Means for Solving the Problems]
An apparatus for molding a synthetic resin object having a bottomed groove according to claim 1 of the present invention moves to a molding die having a cavity, a projecting position projecting into the cavity, and a retreating position retreating from the cavity. And a groove forming member provided in the molding die so that the synthetic resin in a molten state is sealed in the cavity, and then the groove forming member is moved to the projecting position to remove the synthetic resin. A molding apparatus for molding a synthetic resin object having a bottomed groove in a portion corresponding to the groove molding member by solidifying, a communication hole formed in the molding die such that one end communicates with the cavity. And, provided so as to move with the movement of the groove forming member in the communication hole, when the groove forming member is at a regular protruding position, the tip end surface on the cavity side is the When the position of the groove forming member is shifted to the retreat position side with respect to a regular projecting position, the distal end surface is positioned at the same surface as the inner surface of the cavity. A moving member disposed at a position shifted toward the other end of the communication hole.
[0010]
Therefore, since the moving member is provided so as to move with the movement of the groove forming member, the amount of protrusion of the groove forming member into the cavity is reflected on the amount of movement of the moving member, and the groove forming member has a regular protrusion. When it is in the position, since the tip end surface on the cavity side of the moving member is disposed at a position flush with the inner surface of the cavity, the presence or absence of a projection formed on the synthetic resin object by the moving member, The moving amount of the groove forming member can be grasped, and the depth of the bottomed groove of the synthetic resin object having the bottomed groove formed by this molding device can be easily known.
[0011]
A molding method for molding a synthetic resin object having a groove with a bottom according to claim 2 of the present invention includes a sealing step of sealing a synthetic resin in a molten state in a cavity of a molding die, and a groove provided in the molding die. A synthetic resin having a bottomed groove, comprising: a projecting step of moving a molding member to a projecting position projecting into the cavity; and a retreating step of retreating the groove molding member from the cavity after the synthetic resin is solidified. In the method of molding an object, a communication hole formed in the molding die such that one end thereof communicates with the cavity, and when the groove forming member is at a regular protruding position, the front end surface of the cavity side is When the position of the groove forming member is shifted to the retreat position side with respect to a regular projecting position, the distal end surface is positioned at the same surface as the inner surface of the cavity. Against In the projecting step, the moving member is moved along with the movement of the groove forming member by using a mold having a moving member that moves so as to be disposed at a position shifted to the other end side of the communication hole. It is characterized in that it moves within the communication hole.
Therefore, the movement amount of the groove forming member can be grasped by the presence or absence of the projection formed on the synthetic resin object by the moving member, and the depth of the bottomed groove of the synthetic resin object having the bottomed groove formed by this molding method can be determined. Can be easily known.
[0012]
According to a third aspect of the present invention, there is provided a method for determining the depth of a bottomed groove of a synthetic resin object having a bottomed groove, comprising the step of forming a synthetic resin having a bottomed groove formed by the molding apparatus according to the first aspect. A method for determining the depth of a bottomed groove of a resin object, wherein the depth of the bottomed groove is a regular dimension based on the presence or absence of a protrusion formed by flowing a synthetic resin into the communication hole. Is determined.
Therefore, it is possible to determine whether or not the depth of the bottomed groove is a regular dimension only by touching the presence or absence of a protrusion on the inner surface of the cavity formed by the moving member, and to select only a product of a regular dimension, It is possible to prevent the outflow of a synthetic resin object having a bottomed groove having insufficient groove depth from the market.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, one embodiment of a molding apparatus and a molding method of a synthetic resin object having a bottomed groove and a method of determining a depth of the bottomed groove according to the present invention will be described below with reference to the drawings. The molding apparatus and the molding method of the synthetic resin object having the bottomed groove and the method of determining the depth of the bottomed groove according to the present embodiment are applied to the molding of an instrument panel of an automobile.
Here, FIG. 1 is a sectional view of a molding die for molding the instrument panel, and FIG. 2 is a partial perspective view of the molded instrument panel.
Note that the reference numerals used in the present embodiment are irrelevant to the reference numerals used in the above-described conventional example.
[0014]
(Configuration) First, a schematic configuration of the instrument panel 70 will be described. As shown in FIG. 2, an airbag door 72 is formed in the instrument panel 70 of the vehicle. When the airbag is deployed, a “day” shaped broken portion (groove with a bottom) 74 of the airbag door 72 is formed. It is required to form easily so as to break open from the surface and to make the broken portion 74 inconspicuous from the surface.
The break portion 74 is formed by a tapered groove forming member 22 described later from the back surface to the front surface of the instrument panel 70, and a bottomed groove 76 having a depth such that it does not penetrate the surface of the instrument panel 70 is formed at a slight interval. And a large number of them are formed in dotted lines.
[0015]
Next, the configuration of a mold for molding an instrument panel (synthetic resin object) of a vehicle will be described. As shown in FIG. 1, a molding die 10 for molding an instrument panel 70 as a synthetic resin object includes a fixed die 12 fixed to an injection molding device (not shown), The movable mold 14 is supported so as to be able to open the mold, the cylinder 28 is accommodated in the fixed mold 12, a shaft 26 is connected to the cylinder 28, and the cylinder 26 is attached to the tip of the shaft 26. It comprises a pressing member 20 driven by 28 and a control device 30 for controlling the driving of the cylinder 28.
A cavity 18 is formed between the fixed mold 12 and the movable mold 14. A synthetic resin is sealed in the cavity 18 to form an instrument panel 70.
[0016]
As shown in FIG. 3, a plurality of guide grooves 141 communicating with the cavity 18 are arranged in a “day” shape corresponding to the break portion 74 at predetermined portions of the fixed mold 12 forming the airbag door 72. , A communication hole 142 provided near the four corners of the break portion 74 and also communicating with the cavity 18.
On the side opposite to the cavity 18 of the fixed die 12 in which the guide groove 141 and the communication hole 142 are formed, a sliding hole 16 in which the pressing member 20 is slidably provided is provided. On the surface opposite to the shaft 26, a large number of groove forming members 22 and four moving members 24 are erected toward the cavity 18 with a height difference described later.
[0017]
That is, as shown in the partial enlarged cross-sectional view of FIG. 3, the surface of the pressing member 20 opposite to the shaft 26 connected to the shaft 26 includes Is formed upright.
Although only one groove forming member 22 is shown in the figure, a large number of the broken portions 74 are actually erected on the pressing member 20 in the figure.
[0018]
Further, at the position corresponding to the groove depth confirmation portion 78 of the instrument panel 70 on the surface on which the groove forming member 22 of the pressing member 20 is erected, a main body portion 241 and a flat top 242 at the tip are formed. A columnar moving member 24 is provided upright.
That is, the groove forming member 22 is slidable and movable in the guide groove 141 formed in the fixed die 12 by the main body 221 so that the tip end portion 222 faces the cavity 18. The top part 242 is slidably moved by the main body part 241 so as to face the cavity 18 in the communication hole 142 formed in the fixed die 12 so as to be movably set up on the pressing member 20.
[0019]
The height of the tip of the groove forming member 22 and the height of the tip of the moving member 24 are, as shown in FIG. 5, the height of the groove forming member 22 protruding into the cavity 18 and the height of the leading end 222 of the groove forming member 22. When the gap between the movable mold 14 and the outer surface 181 of the cavity 18 moves to a predetermined (regular) gap T1 and moves from the inner surface 182 of the cavity 18 of the fixed mold 12 by L1, as shown in FIG. The top 242 of the moving member 24 is set to be flush with the inner surface 182 of the cavity 18 of the fixed mold 12.
That is, as shown in FIG. 5, when the tip of the tip 222 of the groove forming member 22 is at the same position as the inner surface 182 of the cavity 18, the top 242 of the moving member 24 retreats by L2 from the inner surface 182 of the cavity 18. And set so that L1 = L2.
[0020]
A control device 30 is connected to the hydraulic cylinder 28, and the cylinder 28 is driven by a command of the control device 30 to move the pressing member 20 via the shaft 26, and the movement of the pressing member 20 causes the groove forming member 22 and The moving member 24 is configured to move to the projecting position and the retreating position with respect to the cavity 18.
[0021]
(Operation) Next, a molding method for molding the instrument panel (synthetic resin object) 70 using the molding die 10 configured as described above will be described.
First, the movable mold 14 is clamped to the fixed mold 12 to form the cavity 18, and at the same time, the control device 30 drives the cylinder 28 to pull the pressing member 20 toward the cylinder 28, as shown in FIG. The groove forming member 22 and the moving member 24 are moved to an initial position where the groove forming member 22 and the moving member 24 withdraw from the cavity 18.
[0022]
The synthetic resin in a molten state is injected into the cavity 18 in this state from an injection molding device (not shown), and the synthetic resin in the molten state is sealed in the cavity 18 (enclosing step).
The molten synthetic resin sealed in the cavity 18 also flows into the guide groove 141 and the communication hole 142 communicating with the cavity 18, and contacts the tip 222 of the groove forming member 22 and the top 242 of the moving member 24. (See FIG. 5).
[0023]
When the synthetic resin is sealed in the cavity 18, a force to open the movable mold 14 acts on the fixed mold 12 due to the pressure of the synthetic resin. Is fixed (pressure keeping step).
During this pressure-holding step, the cylinder 28 is driven by the control device 30 to press the pressing member 20, and the groove forming member 22 attached thereto is guided by the guide groove 141 provided in the fixed mold 12, and the cavity 18 is moved. It is moved to a protruding position that protrudes inward (protruding step).
[0024]
FIG. 4 shows an intermediate stage of the projecting step, and FIG. 3 shows a state in which the groove forming member 22 has reached a regular projecting position.
During the pressure holding step, the synthetic resin is in a soft state in which the synthetic resin is gradually hardening from the molten state, so that the groove forming member 22 can protrude into the synthetic resin in the cavity 18. .
[0025]
At the same time that the groove forming member 22 attached to the pressing member 20 projects into the cavity 18 by driving the cylinder 28, the moving member 24 also attached to the pressing member 20 also removes the synthetic resin contacting the top 242 thereof. It moves toward the cavity 18 while pressing.
When the groove forming member 22 reaches the regular projecting position shown in FIG. 3, the top portion 242 of the distal end of the moving member 24 is disposed at a position flush with the inner surface 182 of the cavity 18.
[0026]
As described above, the groove forming member 22 protrudes to the regular protruding position, and the top portion 242 of the moving member 24 is maintained at a position flush with the inner surface 182 of the cavity 18 to cool the forming die 10. Then, the encapsulated synthetic resin is solidified.
After the synthetic resin is solidified, the cylinder 28 is driven in the opposite direction to that described above by a command from the control device 30, and the groove forming member 22 is retracted from the cavity 18 along the guide groove 141. At this time, the moving member 24 also retreats along the communication hole 142 and returns to the initial position (retreating step) (see FIG. 6).
[0027]
When the groove forming member 22 retreats from the cavity 18 and the moving member 24 returns to the initial position, a bottomed groove 76 is formed in the synthetic resin in the cavity 18. When the groove forming member 22 is arranged at the regular projecting position, the groove depth confirmation portion 78 is flush with the inner surface 182 of the cavity 18 and nothing is formed.
[0028]
When the groove forming member 22 is not arranged at the regular projecting position, as shown by the dotted line in FIG. 6, a bottomed groove 76 having a depth smaller than the regular dimension is formed in the synthetic resin. At the same time, a projection 79 is also formed on the groove depth confirmation portion 78.
The height of the protrusion 79 from the inner surface 182 of the cavity, that is, the inner surface of the synthetic resin object 70 is the same as the difference between the depth of the bottomed groove 76 having a depth smaller than the regular size and the regular size. That is, the depth of the bottomed groove 76 is formed to be shallower than the regular dimension by the height of the projection 79.
[0029]
Thereafter, the movable mold 14 is moved relative to the fixed mold 12 in the opening direction to open the mold, and the molded synthetic resin object (instrument panel) 70 is removed from the mold 10. Then, by visually checking the groove depth confirmation unit 78 on the back surface of the instrument panel 70, it is determined whether the groove depth confirmation unit 78 has the protrusion 79.
[0030]
Next, a method of determining the depth of the bottomed groove of the synthetic resin object having the bottomed groove formed as described above will be described.
If the groove depth confirmation portion 78 has a protrusion 79 projecting from the back surface of the instrument panel 70, the amount of protrusion of the groove forming member 22 into the cavity 18 is less than normal, and as a result, It is determined that the depth of the bottomed groove 76 is insufficient, and the thickness T1 of the fractured portion 74 is larger than the regular thickness, and the instrument panel 70 is disposed of as a product with the insufficient bottomed groove depth.
[0031]
When the groove depth confirmation portion 78 is flush with the back surface of the instrument panel 70 and the projection 79 is not formed, the amount of protrusion of the groove forming member 22 into the cavity 18 is normal, and as a result, The bottom groove 76 is formed to have a regular depth, and it is determined that the thickness T1 of the break portion 74 is the regular thickness, and the instrument panel 70 is conveyed to a subsequent process as a passable product.
[0032]
As described above, in the present embodiment, the pressing member 20 driven by the cylinder 28 is slidably housed in the sliding hole 16 provided in the fixed die 12 of the molding die 10, and is fixed to the pressing member 20. A groove forming member 22 movable along a guide groove 141 formed in the mold 12 and a moving member 24 movable along a communication hole 142 also formed in the fixed mold 12 are erected and are combined. After sealing the resin in the cavity 18, the cylinder 28 is driven to project the groove forming member 22 into the synthetic resin to form the bottomed groove 76 which becomes the break portion 74, and the groove forming member 22 has a regular size. It is determined whether or not the protrusion formed by the moving member 24 set such that the top portion 242 is flush with the inner surface 182 of the cavity 18 when protruding only into the cavity 18 exists in the groove depth confirmation portion 78. Look, have Since the depth of the groove 76 can be determined, it can be easily determined in a short time whether or not the depth of the bottomed groove of the synthetic resin object having the bottomed groove is formed to a regular size. .
[0033]
Further, in the present invention, as another embodiment, a monitoring device for monitoring the forming state of the bottomed groove 76 by the groove forming member 22 can be provided.
That is, as shown in FIG. 7, on the side wall of the fixed mold 12, a guide groove 141 formed by drilling an imaging device 80 represented by a CCD camera so as to open on the inner surface 182 of the cavity 18 can be photographed. A monitoring device is installed so that the image is displayed on an image display device such as a personal computer (not shown) so as not to interfere when tightened.
[0034]
Then, in the molding process described above, after molding, after the mold is opened and the synthetic resin object 70 is taken out of the molding die 10, the cylinder 28 is driven again to move the pressing member 20 toward the cavity 18, As shown in FIG. 8, the distal ends 222 of all the groove forming members 22 are made to protrude from the guide grooves 141.
The protruding state of the tip 222 is photographed by the above-described imaging device 80, and the image is compared with an image of the regular tip 222 displayed in advance to monitor whether there is a shortage of the tip 222. .
[0035]
If there is no missing part completely coincident with the regular image, the synthetic resin object 70 is conveyed to the next step as an acceptable product.
If there is an insufficiency, it is determined that the groove forming member 22 is damaged by some influence and the tip 222 is chipped, and if the tip 222 is chipped, the bottomed groove 76 of that portion is formed to a regular depth. However, since the entire broken portion 74 is not properly formed, the synthetic resin object 70 is excluded as a defective product.
In this manner, according to the molding method of the second embodiment, the molding state of the broken portion 74 of the airbag door 72 can be easily monitored and determined in a short time. It no longer flows to the market.
[0036]
Note that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention.
For example, in the above-described embodiment, the shape of the broken portion of the airbag door has been described as a “Japanese” shape. However, the present invention is not limited to this, and an “H” shape or an “I” shape is also possible. .
Further, in the above embodiment, the cylinder, the pressing member, and the groove forming member are described as being provided on the fixed mold side, but the side provided with these may be a movable mold.
[0037]
【The invention's effect】
The present invention provides a molding die, a groove forming member movable to a position protruding into the cavity and a position retracted from the cavity, and provided so as to move with a movement of the groove forming member in a communication hole communicating with the cavity. When the groove forming member is at the regular projecting position, the front end surface on the cavity side is arranged at a flush position substantially flush with the inner surface of the cavity, and the position of the groove forming member is relative to the regular projecting position. When it is shifted to the retreat position side, a forming device including a moving member whose tip end surface is shifted to the other end side of the communication hole with respect to the flush position is configured, and using this forming device The synthetic resin is sealed in the cavity, and the groove forming member is protruded into the cavity. When the groove forming member is at a regular protruding position, the front end surface on the cavity side is substantially the same as the inner surface of the cavity. Placed in When the position of the forming member is shifted to the retreat position side with respect to the regular projecting position, the moving member arranged at the position where the front end surface is shifted to the other end side of the communication hole with respect to the flush surface is moved. By molding a synthetic resin object having a bottomed groove, it is determined whether or not the depth of the bottomed groove is a regular dimension based on the presence or absence of the protrusion formed by the flow of the synthetic resin into the communication hole. Therefore, the depth of the bottomed groove can be easily determined in a short time by touching the protrusion.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a molding die for a synthetic resin object according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a synthetic resin object (instrument panel) according to one embodiment of the present invention.
FIG. 3 is a partially enlarged cross-sectional view of a molding die for a synthetic resin object according to one embodiment of the present invention, showing a state in which a groove molding member has completely protruded.
FIG. 4 is a partially enlarged cross-sectional view of a molding die for a synthetic resin object according to one embodiment of the present invention, showing a groove forming member being protruded.
FIG. 5 is a partially enlarged sectional view of a molding die for a synthetic resin object according to one embodiment of the present invention, showing an initial state of a groove molding member.
FIG. 6 is a partially enlarged cross-sectional view of a molding die of a synthetic resin object according to one embodiment of the present invention, showing a state in which a groove forming member has completely retreated.
FIG. 7 is a perspective view showing a monitoring state of a synthetic resin object according to another embodiment of the present invention, showing a state immediately after the mold is opened.
FIG. 8 is a perspective view showing a state of monitoring a synthetic resin object according to another embodiment of the present invention, showing a state where the groove forming member is again projected after the mold is opened.
FIG. 9 is a perspective view showing a part of a conventional groove forming member.
FIG. 10 is a sectional view showing a part of a conventional groove forming member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Molding apparatus 10 Molding die 12 Fixed die 14 Movable die 142 Communication hole 18 Cavity 22 Groove forming member 24 Moving member 242 Top part 70 Synthetic resin object 76 Bottom groove

Claims (3)

A mold having a cavity, a groove forming member provided in the mold so as to be able to move to a protruding position protruding into the cavity and a retreat position retracted from the cavity, and provided in the cavity. After enclosing the synthetic resin in a molten state, by moving the groove forming member to the projecting position and solidifying the synthetic resin, a synthetic resin object having a bottomed groove in a portion corresponding to the groove forming member is formed. A molding device for molding,
A communication hole formed in the mold so that one end communicates with the cavity;
The groove-forming member is provided in the communication hole so as to move with the movement of the groove-forming member, and when the groove-forming member is at a regular projecting position, the tip surface on the cavity side is substantially flush with the inner surface of the cavity. When the position of the groove forming member is shifted to the retreat position side with respect to a regular protruding position, the tip end surface is other than the communication hole with respect to the flat surface position. A moving member arranged at a position shifted to the end side,
An apparatus for molding a synthetic resin object having a bottomed groove. An encapsulating step of sealing the synthetic resin in a molten state in a cavity of a mold, a projecting step of moving a groove forming member provided in the mold to a projecting position projecting into the cavity, and after the synthetic resin is solidified, A retreating step of retreating the groove forming member from the inside of the cavity, comprising:
A communication hole formed in the mold so that one end communicates with the cavity, and when the groove forming member is at a regular protruding position, the tip surface on the cavity side is substantially flush with the inner surface of the cavity. When the position of the groove forming member is shifted to the retreat position side with respect to a regular projecting position, the other end of the communication hole is positioned with respect to the flat surface. Using a mold having a moving member that moves so as to be arranged at a position shifted to the side,
The method of molding a synthetic resin object having a bottomed groove, wherein in the projecting step, the moving member moves in the communication hole as the groove forming member moves. A method for determining the depth of a bottomed groove of a synthetic resin object having a bottomed groove formed by the molding apparatus according to claim 1,
The presence or absence of a protrusion formed by the flow of the synthetic resin into the communication hole determines whether or not the depth of the bottomed groove is a regular dimension. Depth determination method.

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