JP4237678B2 - Injection molding machine and injection molding method - Google Patents

Description

  The present invention relates to an injection molding machine and an injection molding method.

  Conventionally, in an injection molding machine for molding a disk substrate as a molded product, resin melted in a heating cylinder is filled in a cavity space in a disk molding die, and the inside of the cavity space is filled. The disk substrate is obtained by cooling and solidifying in FIG.

  For this purpose, the injection molding machine includes a disk-molding mold comprising a fixed-side mold assembly and a movable-side mold assembly, an injection device for filling the cavity space with the resin, and a movable-side mold assembly. A mold clamping device for bringing the mold assembly into and out of contact with the stationary-side mold assembly is provided. Then, the mold assembly on the movable side is advanced and retracted by the mold clamping device to perform mold closing, mold clamping and mold opening of the disk molding mold, and at the time of mold closing and clamping, the fixed mold assembly A cavity space is formed between the disk plate and the disk plate of the movable mold assembly.

  The injection device includes a heating cylinder, an injection nozzle attached to the front end of the heating cylinder, and a screw that is rotatably and reciprocally disposed within the heating cylinder.

  In the measuring step, the screw is rotated, the resin is melted and stored in front of the screw, and the screw is retracted accordingly. During this period, the disk mold is closed and clamped. Is done. Subsequently, in the injection step, the screw is advanced, and the resin stored in front of the screw is injected from the injection nozzle to fill the cavity space. In the pressure holding / cooling step, the resin in the cavity space is cooled, drilled, and a disk substrate is formed. Subsequently, mold opening is performed, and the disk substrate is taken out.

  By the way, in order to perform the drilling process, a die having a concave portion is formed at the front end of the sprue bush disposed in the fixed-side mold assembly so as to face the cavity space. A cut punch having a front end having a shape corresponding to the die is disposed on the movable die assembly so as to face the sprue bush. A hole can be made in the resin cooled in the cavity space by advancing the cut punch and fitting the front end into the die (see, for example, Patent Document 1).

In this case, the cut punch is advanced from the advance start position to the target position by speed control, reaches the target position, and then protrudes while maintaining the cut punch at the target position by pressure control. And when the predetermined time elapses, the vehicle is moved backward.
JP-A-8-187752

  However, in the conventional injection molding machine, when the resin in the cavity space shrinks with cooling, the movable platen to which the movable mold assembly is attached gradually moves forward. Since the cut punch is kept at the target position and the pressure is kept constant, the cut punch is also advanced in the same way, and the amount of protrusion increases, and as a result, gate cut flash occurs on the disk substrate. End up.

  An object of the present invention is to provide an injection molding machine and an injection molding method capable of solving the problems of the conventional injection molding machine and preventing the occurrence of gate cut flash on a molded product.

  For this purpose, in the injection molding machine of the present invention, a first support member, a first mold assembly attached to the first support member and having a die formed at a front end thereof, and the first mold A second support member disposed opposite to the support member; a second support member provided with the second support member; and a cut punch attached to the second support member and disposed to move forward and backward with respect to the second support member. A die assembly, a drive unit for drilling processing for advancing and retracting the cut punch, and driving the drive unit to advance the cut punch, and inserting the front end of the cut punch into the die, Advance processing means for performing an opening process, and after the drilling process has been performed, the drive unit is driven to retract the cut punch in accordance with the advance of the second support member as the molding material contracts Retreat processing means.

  According to the present invention, in an injection molding machine, a first support member, a first mold assembly attached to the first support member and having a die formed at a front end thereof, and the first mold A second support member disposed opposite to the support member; a second support member provided with the second support member; and a cut punch attached to the second support member and disposed to move forward and backward with respect to the second support member. A die assembly, a drive unit for drilling processing for advancing and retracting the cut punch, and driving the drive unit to advance the cut punch, and inserting the front end of the cut punch into the die, Advance processing means for performing opening processing, and retreat for driving the drive unit after the drilling processing is performed and retracting the cut punch in accordance with the advance of the second support member as the molding material contracts And processing means.

  In this case, after the cut punch is advanced, the front end of the cut punch is fitted into the die and drilling is performed, and then the second support member is advanced as the molding material contracts. Since the cut punch is retracted, it is possible to prevent the gate cut from occurring in the molded product.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a cross-sectional view of the disk-molding mold according to the first embodiment of the present invention.

  In the drawing, reference numeral 12 denotes a fixed-side mold assembly as a first mold assembly that is attached to a fixed platen (not shown) as a first support member (not shown) by a bolt (not shown) via a mounting plate 13. The mold assembly 12 includes a base plate 15 as a first support plate, a disk plate 16 as a first mirror plate attached to the base plate 15 with a bolt (not shown), and a fixed platen side in the mounting plate 13. And a locating ring 23 for positioning the mold assembly 12 with respect to the stationary platen, and a sprue bushing 24 disposed adjacent to the locating ring 23. At the front end (left end in the figure) of the sprue bushing 24, a die 28 comprising a concave portion is formed so as to face the cavity space C. The sprue 26 through which the resin passes is formed. The injection apparatus includes a heating cylinder (not shown), the injection nozzle attached to the front end of the heating cylinder, and a screw that is rotatably and reciprocally disposed in the heating cylinder.

  The disc plate 16 is provided with a stamper (not shown) for forming a fine pattern having irregularities on the information surface of a disc substrate (not shown) as a molded product, and the front half of the sprue bushing 24 (the left half in the figure). A stamper presser bush 14 for pressing the inner peripheral edge of the stamper is disposed on the radially outer side of the part. The mold assembly 12 is also provided with an air probe or the like (not shown).

  An annular abutment ring 18 is attached to the outer peripheral edge of the disc plate 16 by a bolt b1, and an annular first outer peripheral ring 19 is formed on the base plate radially outward from the disc plate 16 and the abutment ring 18. 15 is attached.

  On the other hand, 32 is a movable side mold assembly as a second mold assembly which is attached to a movable platen (not shown) as a second support member by a bolt (not shown). A base plate 35, an intermediate plate 40 as a second support plate attached to the base plate 35 with bolts b2, a disk plate 36 as a second mirror surface plate attached to the intermediate plate 40 with bolts b3, and the base plate 35 The guide member 44 is disposed so as to face the movable platen and is attached to the intermediate plate 40 by bolts b4, and is opposed to the sprue bush 24. The cut punch 48 is arranged freely, and the cut punch 48 is It has a shape in which the end (right end in the drawing) corresponding to the die 28.

  An annular cab ring 37 is disposed on the outer peripheral edge of the disc plate 36 so as to be movable with respect to the disc plate 36 and opposed to the abutting ring 18, and the disc plate 36 and the cab ring. An annular second outer peripheral ring 38 is attached to the intermediate plate 40 so as to face the first outer peripheral ring 19 radially outward from 37. The cavity ring 37 is attached to the rod 41 by a bolt b5 and is movably disposed with respect to the intermediate plate 40 via the rod 41. A spring 63 as an urging member is disposed at the rear end (left end in the figure) of the rod 41 in order to urge the cavity ring 37 toward the fixed side. Reference numeral 39 denotes a cavity ring presser attached to the second guide ring 38 with a bolt (not shown). The cavity ring presser 39 is locked to the outer peripheral edge of the cavity ring 37. The cavity ring 37 is protruded from the front end surface (right end surface in the figure) of the disk plate 36, and the outer peripheral edge of the disk substrate is formed by the inner peripheral surface of the cavity ring 37.

  A flange 51 formed integrally with the cut punch 48 is disposed in the guide member 44 so as to be movable back and forth along the guide member 44, and a rear end 51 a of the flange 51 is received by the guide member 44. Further, a cut punch return spring 52 is disposed in front of the flange 51 (right side in the figure), and the flange 51 is biased rearward (left side in the figure) by the cut punch return spring 52. Behind the cut punch 48, a drilling motor (not shown) as a driving unit for drilling is provided, and the cut punch 48 can be advanced and retracted by driving the drilling motor. For this purpose, a drive rod (not shown) is disposed behind the cut punch 48, and the rotational motion generated by driving the drilling motor is linearly moved between the drive rod and the drilling motor. For example, a ball screw is provided as a first movement direction conversion unit for converting into the first movement direction. It should be noted that a hydraulic cylinder can be used instead of the drilling motor as the driving unit for drilling.

  A disk molding die is constituted by the mold assemblies 12, 32, and a mold clamping device (not shown) is provided to bring the mold assembly 32 into and out of contact with the mold assembly 12. Then, a mold clamping motor as a mold clamping drive unit of the mold clamping device is driven and the mold assembly 32 is advanced and retracted, whereby the disk molding mold is closed, clamped and opened. The cavity space C is formed between the disk plates 16 and 36 during mold clamping. For this purpose, a toggle mechanism (not shown) is provided behind the movable platen, and the rotary motion generated by driving the mold clamping motor is changed between the toggle mechanism and the mold clamping motor into a linear motion. For example, a ball screw is provided as a second movement direction conversion unit for conversion. Note that a mold clamping cylinder may be used as the mold clamping drive unit instead of the mold clamping motor.

  On the radially outer side of the front half (right half in the figure) of the cut punch 48, an eject tab 62 for projecting the disk substrate is disposed so as to be able to advance and retreat, and radially outward from the eject tab 62. An air probe 47 for releasing the disk substrate from the disk plate 36 by blowing compressed air onto the disk substrate is disposed.

  First and second temperature control channels 93 and 94 are formed in the disk plates 16 and 36, respectively. The first and second temperature control channels 93 and 94 are used for temperature control of water, oil, air, and the like. By supplying the medium, the disk plates 16 and 36 are cooled.

  In the measuring step, the screw is rotated, the resin is melted and stored in front of the screw, and the screw is retracted accordingly. During this period, the disk mold is closed and clamped. Is done. Subsequently, in the injection step, the screw is advanced, and the resin stored in front of the screw is injected from the injection nozzle, passes through the sprue 26, and is filled into the cavity space C.

  Then, in the pressure holding / cooling step, the pressure of the resin in the cavity space C is kept constant, and during that time, the resin in the cavity space C is cooled and solidified to form a prototype substrate that is a prototype of the disk substrate. However, before the resin is completely solidified, a drilling process is performed on the original substrate, the drilling motor is driven, and the cut punch 48 is moved forward (moved to the right in the drawing). . At this time, the front end of the cut punch 48 is fitted into the die 28, a hole is made in the original substrate, and a disk substrate is formed. Subsequently, the mold is opened, and the disk substrate is ejected by the eject tabs 62 and the compressed air and taken out by a take-out device (not shown).

Next, a control device for performing drilling in the injection molding machine configured as described above will be described.
FIG. 1 is a block diagram showing a control device for an injection molding machine according to a first embodiment of the present invention, and FIG. 3 is a first diagram showing a state of a cut punch according to the first embodiment of the present invention. FIG. 5 is a second view showing the state of the cut punch in the first embodiment of the present invention, FIG. 5 is a third view showing the state of the cut punch in the first embodiment of the present invention, and FIG. It is a time chart which shows the operation | movement of the cut punch in the 1st Embodiment of invention. For convenience of explanation, in FIGS. 3 to 5, the stamper presser bush 14 (FIG. 1), the eject tab 62 and the air probe 47 are omitted.

  In FIG. 1, 55 is a control unit, 56 is a setting device, 57 is a drilling motor, 58 is an encoder as a first position detection unit for detecting the position of the rotor of the drilling motor 57, 59 is A position sensor as a second position detection unit for detecting the position of the movable platen relative to the fixed platen, 61 is a pressure sensor as a pressure detection unit for detecting a protruding pressure for protruding the cut punch 48, and 65 is It is a memory as a recording device. As the position sensor 59, a position sensor that is disposed on a frame of an injection molding machine and directly detects the position of the movable platen can be used. Further, a load cell can be used as the pressure sensor 61. In the case where a hydraulic cylinder is used instead of the hole forming motor 57, a hydraulic sensor can be used as the pressure sensor 61. 3 to 5, 16 and 36 are disk plates, 24 is a sprue bush, and 26 is a sprue.

  A first position detection processing unit (not shown) of the control unit 55 performs a first position detection process, reads the position of the rotor detected by the encoder 58, and determines the movement of the cut punch 48 from the advance start position. The position of the cut punch 48 shown, that is, the cut punch position Sc is detected. In the present embodiment, the advance start position is such that the front end (right end in FIGS. 3 to 5) of the cut punch 48 is the same position as the front end of the disk plate 36 or slightly forward (right in FIGS. 3 to 5). It is set as a relative position to the movable platen to be placed.

  A second position detection processing unit (not shown) of the control unit 55 performs a second position detection process, reads the sensor output of the position sensor 59, and detects the position of the movable platen, that is, the movable platen position Sp. To do. The platen distance sensor is used to detect the movable platen position Sp by detecting the distance between the fixed platen and the movable platen, or the rotor position of the mold clamping motor is detected. The movable platen position Sp can be detected based on the position. Further, in an injection molding machine having a mold clamping device provided with a toggle mechanism, the position of the crosshead can be detected by a predetermined position sensor, and the movable platen position Sp can be detected based on the position of the crosshead.

  A rotation speed detection processing unit (not shown) of the control unit 55 performs a rotation speed detection process, reads the position of the rotor, differentiates it, and detects the rotation speed of the drilling motor 57, that is, the motor rotation speed NM.

  Then, when the pressure holding / cooling process is started, the forward processing means (not shown) of the control unit 55 performs the forward processing, drives the drilling motor 57 at a predetermined timing t1, and the cut punch 48 is The vehicle is moved forward (moved rightward in FIGS. 3 to 5) in the direction of arrow A from the advance start position to the target arrival position Sc1. As shown in FIG. 3, the target reaching position Sc1 is set so that the front end of the cut punch 48 is inserted into the die 28 by a distance ρ, and the appropriate target reaching position Sc1 causes a gate cut flash. It is calculated in advance by an experiment or the like so that it can be prevented.

In the advance processing, the speed control of the hole drilling motor 57 is performed. For this purpose, the speed control processing means of the forward processing means performs speed control processing, and reads the motor target rotational speed NM ^* representing the target value of the motor rotational speed NM set by the setting device 56 and recorded in the memory 65. The PI control is performed based on the speed deviation ΔNM between the motor target rotational speed NM ^* and the motor rotational speed NM detected by the rotational speed detection processing means.

  Meanwhile, the forward processing means reads the cut punch position Sc detected by the first position detection processing means, and determines whether the cut punch 48 has reached the target arrival position Sc1 based on the cut punch position Sc. If the cut punch 48 reaches the target arrival position Sc1 at the timing t2, the forward process is terminated.

In the speed control process, if the motor rotation speed NM is excessively high, a gate cut beam is generated. Therefore, an appropriate motor rotation speed NM is calculated in advance by trial molding, experiment, etc., and is used as the motor target rotation speed NM ^*. Is set.

In the forward process, pressure control can be performed in addition to the speed control of the drilling motor 57. In that case, a set value of the protruding pressure of the cut punch 48 is set in advance by the setting device 56 and recorded in the memory 65, and the forward processing means detects the set value and the protruding pressure detected by the pressure sensor 61. The motor target rotational speed NM ^* is set in correspondence with the deviation. Therefore, the protruding pressure of the cut punch 48 can be kept constant.

Subsequently, the pressure holding processing unit (not shown) of the control unit 55 performs pressure holding processing, reads the set value of the protruding pressure from the memory 65, and the deviation between the set value and the protruding pressure detected by the pressure sensor 61. And the motor target rotational speed NM ^* is set in correspondence with the deviation. As a result, as shown in FIG. 4, the cut punch 48 is slightly retracted (moved leftward in FIGS. 3 to 5) from the target arrival position Sc1 in the arrow B direction, and at the timing t3, the pressure holding position Sc2. Placed in. At the pressure holding position Sc2, the set value of the protruding pressure is set so that the front end of the cut punch 48 does not come out of the die 28 completely.

  By the way, after the cut punch 48 is placed at the pressure holding position Sc2, the resin in the cavity space C contracts with cooling, and when the movable platen advances by that amount, the cut punch 48 is also advanced in the same manner. The protrusion amount of the punch 48 increases, and accordingly, a gate cut flash occurs.

  Therefore, the position adjustment processing means (not shown) of the control unit 55 performs the position adjustment processing, and even if the resin in the cavity space C contracts with cooling and the movable platen moves forward, the cut punch 48 is not assembled into the mold. The cut punch position Sc is adjusted so that it does not move relative to the solid 12.

First, the standby processing means of the position adjustment processing means performs standby processing and performs pressure control and speed control of the hole forming motor 57. Therefore, when the cut punch 48 is placed at the pressure holding position Sc2 at the timing t3, the standby processing means sets the motor target rotational speed NM ^* to zero (0) and sets the protruding pressure to a predetermined value for a predetermined time τ1. Then, it waits until the change in the movable platen position immediately after the resin filling is finished.

  Subsequently, the reverse processing means of the position adjustment processing means performs the reverse processing, and when the time τ1 has elapsed and the fluctuation of the movable platen position is settled at timing t4, the cut punch 48 is associated with the reverse of the movable platen. Starts to move in the direction of arrow B.

Therefore, the setting device 56 sets in advance the elapsed time from the start to the end of the retraction of the cut punch 48 and the target cut punch position Sc ^* representing the target value of the cut punch position Sc ^. , And recorded in the memory 65 as a position pattern.

  Further, the movement amount calculation processing means of the position adjustment processing means performs a movement amount calculation process, reads the movable platen position Sp detected by the position sensor 59 as an initial position at timing t4, and then starts from the initial position. The amount of movement of the movable platen is calculated.

Then, the backward processing means controls the position of the hole punching motor 57, reads the elapsed time from the timing t4, reads the target cut punch position Sc ^* corresponding to the elapsed time from the memory 65, and the cut punch. The position Sc is read, and PI control is performed based on the position deviation ΔSc between the target cut punch position Sc ^* and the cut punch position Sc.

  In the present embodiment, as shown in FIG. 6, the position pattern includes a cut punch as the time passes so that the cut punch 48 is retracted from the pressure holding position Sc2 by the amount of advance of the movable platen. The position Sc is reduced with a predetermined inclination. In this case, the pressure holding position Sc2 is a position at which the cut punch 48 starts to retreat, that is, a retreat start position, but is substantially the same as the cut punch position Sc when the fluctuation of the movable platen position Sp is settled at the timing t4. Are the same.

  When the pressure holding / cooling process is completed at timing t5, the backward processing means further retracts the cut punch 48 and places it at the forward start position. In this case, the retraction speed of the cut punch 48 is increased in order to shorten the molding cycle.

  As described above, when the resin in the cavity space C contracts as it cools, and the movable platen advances, for example, by the distance ε, the cut punch 48 moves to the pressure holding position Sc2 as shown in FIG. Therefore, the cut punch 48 is placed at the same pressure holding position Sc2 in the die 28. In this way, the position of the cut punch 48 with respect to the mold assembly 12 is adjusted and the cut punch 48 is prevented from moving forward, so that it is possible to prevent the gate cut from being generated on the disk substrate.

  Next, a second embodiment of the present invention will be described.

  FIG. 7 is a time chart showing the operation of the cut punch in the second embodiment of the present invention.

  In this case, as shown in the figure, the setter 56 (FIG. 1) causes the amount of movement of the cut punch 48 (FIG. 3) from the pressure holding position Sc2 to be stepwise corresponding to the elapsed time from the timing t4. And is recorded in the memory 65 as a position pattern. The amount of movement of the cut punch 48 at this time is set by experiments to sufficiently prevent the occurrence of gate cut flash.

  When the pressure holding / cooling process is started, the forward processing means of the control unit 55 performs forward processing, and drives a drilling motor 57 as a driving source for drilling at a predetermined timing t1. The cut punch 48 is advanced from the advance start position to the target arrival position Sc1. Therefore, the forward processing means reads the cut punch position Sc detected by the first position detection processing means, and whether or not the cut punch 48 has reached the target arrival position Sc1 based on the cut punch position Sc. When the cut punch 48 reaches the target arrival position Sc1 at the timing t2, the forward movement process is terminated.

Next, the pressure holding processing means of the control unit 55 performs pressure holding processing, reads the set value of the protruding pressure of the cut punch 48 from the memory 65, and sets the set value and the protruding pressure detected by the pressure sensor 61. The motor target rotational speed NM ^* is set in correspondence with the deviation. As a result, the cut punch 48 is slightly retracted from the target arrival position Sc1 in the direction of arrow B, and is placed at the pressure holding position Sc2 at timing t3.

  Subsequently, the position adjustment processing means of the control unit 55 performs position adjustment processing, even if the resin in the cavity space C contracts with cooling and the movable platen as the second support member advances, The position of the cut punch 48 is adjusted so that the cut punch 48 does not move forward.

First, the standby processing means of the position adjustment processing means performs standby processing and performs pressure control and speed control of the hole forming motor 57. For this reason, the waiting processing means sets the motor target rotation speed NM ^* to zero, sets the protruding pressure to a predetermined value for a predetermined time τ1, and the fluctuation of the movable platen position immediately after the resin filling is completed is settled. Wait.

  Subsequently, the reverse processing means of the position adjustment processing means performs the reverse processing, and when the time τ1 has elapsed and the fluctuation of the movable platen position is settled at timing t4, the cut punch 48 is associated with the reverse of the movable platen. Start retreating. The movement amount calculation processing means of the position adjustment processing means performs a movement amount calculation process, reads the movable platen position Sp detected by the position sensor 59 as an initial position at timing t3, and then reads from the initial position. The amount of movement of the movable platen is calculated.

  Then, the backward processing means controls the position of the punching motor 57, reads the elapsed time from the timing t4, reads the movement amount of the cut punch 48 corresponding to the elapsed time, and moves the cut punch 48 backward.

  Then, when the pressure holding / cooling process is completed at timing t5, the retreat processing means rapidly retreats the cut punch 48.

  In each of the above embodiments, when the cut punch 48 reaches the target arrival position Sc1, the pressure holding process is performed, the cut punch 48 is placed at the pressure holding position Sc2, and then the standby process is performed at the pressure holding position Sc2. However, when the cut punch 48 reaches the target arrival position Sc1, standby processing can be performed at the target arrival position Sc1.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

It is a block diagram which shows the control apparatus of the injection molding machine in the 1st Embodiment of this invention. It is sectional drawing of the metal mold | die for disk formation in the 1st Embodiment of this invention. It is a 1st figure which shows the state of the cut punch in the 1st Embodiment of this invention. It is a 2nd figure which shows the state of the cut punch in the 1st Embodiment of this invention. It is a 3rd figure which shows the state of the cut punch in the 1st Embodiment of this invention. It is a time chart which shows the operation | movement of the cut punch in the 1st Embodiment of this invention. It is a time chart which shows the operation | movement of the cut punch in the 2nd Embodiment of this invention.

Explanation of symbols

12, 32 Mold assembly 28 Die 48 Cut punch 55 Control unit 57 Motor for drilling 58 Encoder 59 Position sensor

Claims (10)

(A) a first support member;
(B) a first mold assembly attached to the first support member and having a die formed at the front end;
(C) a second support member disposed to face the first support member;
(D) a second mold assembly provided with a cut punch attached to the second support member and disposed so as to be movable forward and backward with respect to the second support member;
(E) a drive unit for drilling for advancing and retracting the cut punch;
(F) by driving the drive unit to advance the cut punch, by fitting the front end of the mosquito Ttopanchi to the die, a forward processing means for boring,
(G) after said boring is performed to drive the driving unit, and a backward process means to retract said cut punch in association with the advance of the second support member with the shrinkage of the molding material An injection molding machine characterized by that. (A) having a position detector for detecting the position of the cut punch relative to the second support member;
(B) The injection molding machine according to claim 1, wherein the backward processing means includes position adjustment processing means for adjusting the position of the cut punch by driving the driving unit.   The injection molding machine according to claim 2, wherein the position adjustment processing means holds the position of the cut punch with respect to the first mold assembly. (A) having a position detector for detecting the position of the second support member relative to the first support member;
(B) The injection molding machine according to claim 2, wherein the position adjustment processing means adjusts the position of the cut punch in correspondence with the position of the second support member.   2. The injection molding machine according to claim 1, further comprising a standby processing unit configured to wait for the retraction of the cut punch for a predetermined time after the drilling is performed.   The injection molding machine according to claim 2, wherein the position adjustment processing unit performs speed control of the drive unit.   The injection molding machine according to claim 2, wherein the position adjustment processing unit performs pressure control of the driving unit.   The injection molding machine according to claim 4, wherein the position adjustment processing means continuously changes the position of the cut punch.   The injection molding machine according to claim 4, wherein the position adjustment processing unit changes the position of the cut punch stepwise. A first support member, a first mold assembly attached to the first support member and having a die formed at a front end thereof, and a second support disposed to face the first support member In an injection molding method of an injection molding machine having a member and a second mold assembly that is attached to the second support member and includes a cut punch that is disposed so as to be movable forward and backward with respect to the second support member ,
(A) said to advance the cut punch, the front end of the mosquitoes Ttopanchi by fitting the die performs drilling,
(B) An injection molding method, wherein after the perforating process is performed, the cut punch is retracted in accordance with the advance of the second support member accompanying the shrinkage of the molding material.

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