Multi-plunger type transfer molding machine

Abstract

This multi-plunger type transfer molding machine 1 comprises: individual support parts 131; a main drive part 116; individual drive parts 132-1, 132-2; individual thrust detectors 137; and individual control parts 150 for performing, on the individual drive parts 132-1, 132-2, feedback control for exerting thrust for making a plurality of plungers 1363 advance in a predetermined direction with respect to the individual support parts 131 or feedback control for exerting thrust for making the plungers retreat in a predetermined direction with respect to the individual drive parts 132-1, 132-2, the feedback control being performed on the basis of the value of the thrust from the individual thrust detectors 137 so that the difference in the thrust applied to the plurality of plungers 1363 is eliminated or the difference in the thrust applied to the plurality of plungers 1363 increases.

Description

Multi-plunger transfer molding machine

[0001] The present invention relates to a multi-plunger type transfer molding machine.

[0002] Conventionally, so-called multi-plunger transfer molding machines have been known in which resin material is simultaneously injected into multiple cavities formed by multiple slots in a mold through a sprue, runner, and gate to perform molding (see, for example, Patent Documents 1 and 2).

[0003] JP-A No. 8-156011 JP-A No. 11-291282

[0004] In a multi-plunger transfer molding machine, it is required that each plunger fills each cavity with resin material at an equal pressure. For example, the conventional multi-plunger transfer molding machine described in Patent Document 1 uses a plunger pressure equalization device that introduces pressurized fluid into a cylinder portion in which the piston of each plunger is fitted and then discharges a portion of the pressurized fluid to the outside of the cylinder portion. Furthermore, the conventional multi-plunger transfer molding machine described in Patent Document 2 uses a pressure equalization unit that absorbs variations in the pressing action of the plungers and adjusts them to be uniform by the flow of liquid sealed in a hydraulic closed circuit formed to communicate between multiple piston rods to which plungers can be attached.

[0005] When a fluid is used in this way, a fluid flow path must be formed, which complicates the configuration of the multi-plunger transfer molding machine. Furthermore, when a multi-plunger transfer molding machine is used to fill multiple locations in a single cavity with resin material, some locations in the cavity have narrow and some have wide shapes. Therefore, if the resin material is filled at equal pressure into multiple locations in a single cavity, it may be possible to fill the wide-shaped portions with resin material, but not the narrow-shaped portions.

[0006] The present invention aims to provide a multi-plunger type transfer molding machine that can avoid the configuration of the multi-plunger type transfer molding machine becoming complicated and that can fill resin material into cavities with high precision using each plunger.

[0007] The present invention relates to a multi-plunger type transfer molding machine having a plurality of plungers that can pump resin into a cavity through a sprue, runner, and gate of a mold, and the machine includes: individual support units that support the plurality of plungers so that they can simultaneously advance and retreat in a predetermined direction; a main drive unit that moves the individual support units forward and backward in the predetermined direction; a plurality of individual drive units that individually move each of the plungers forward and backward in the predetermined direction relative to the individual support units; individual thrust detectors that are provided on the individual support units and detect the value of thrust applied to each of the plungers in the forward direction in the predetermined direction; and an individual control unit that performs feedback control on each of the individual drive units so that the plurality of individual drive units apply thrust that advances the plurality of plungers in the predetermined direction relative to the individual support units or applies thrust that retreats the plurality of plungers in the predetermined direction based on the thrust values ​​from the individual thrust detectors, so that differences in thrust applied to the plurality of plungers are eliminated.

[0008] Preferably, the individual thrust detector is provided for each of the plungers, the individual drive unit is configured by a servo motor, and the individual thrust detector is configured by a load cell.

[0009] It is also preferable that the individual support section is provided with a main thrust detector that detects the value of thrust applied from the main drive section to the individual support section in the forward direction in the predetermined direction, and the individual control section performs feedback control to adjust the value of thrust applied from the main drive section to the individual support section based on the thrust value from the main thrust detector.

[0010] Furthermore, it is preferable that the plurality of plungers are capable of pumping resin into a plurality of cavities through a sprue, runner, and gate of the mold, and that the individual control unit performs feedback control on each of the individual drive units to apply a thrust that advances the plurality of plungers in the predetermined direction relative to the individual support units, or a feedback control to apply a thrust that retreats the plurality of plungers in the predetermined direction, based on the thrust value from the individual thrust detector, so that there is no difference in the thrust applied to the plurality of plungers.

[0011] Furthermore, it is preferable that the multiple plungers are capable of pumping resin to multiple locations in one cavity through the sprue, runner, and gate of the mold, and that the individual control unit performs feedback control on each of the individual drive units to apply a thrust that moves the multiple plungers forward in the specified direction relative to the individual support units, or a feedback control to apply a thrust that moves the multiple plungers backward in the specified direction, based on the thrust value from the individual thrust detector, so that the difference in thrust applied to the multiple plungers becomes greater.

[0012] According to the present invention, it is possible to provide a multi-plunger type transfer molding machine that can avoid the configuration of the multi-plunger type transfer molding machine becoming complicated and that can fill resin material into a cavity with high precision using each plunger.

[0013] The present invention relates to a transfer molding machine, a transfer molding machine for molding a molded article ...

[0014] A transfer molding machine 1 according to this embodiment will be described below with reference to the drawings. For convenience of explanation, the up-down direction in FIG. 1, which coincides with the vertical direction, is defined as the up-down direction.

[0015] The transfer molding machine 1 is a so-called multi-plunger type transfer molding machine that simultaneously fills a thermosetting resin material into a plurality of cavities formed by a plurality of slots in a mold to perform molding.

[0016] As shown in FIG. 1, the transfer molding machine 1 includes a base 111, an individual support section 131, a main transfer servo motor 116 (hereinafter referred to as the "main motor 116") as the main drive section, a main transfer load cell 121 (hereinafter referred to as the "main load cell 121") as the main thrust detector, multi-plunger servo motors 132-1 and 132-2 (hereinafter referred to as the "multi-motors 132-1 and 132-2") as individual drive sections, a multi-plunger load cell 137 (hereinafter referred to as the "multi-load cell 137") as an individual thrust detector, a control device 150 as an individual control section, a plunger 1363, and a mold (not shown).

[0017] The base 111 is disposed above the mold and supports the entire device that drives the plunger 1363 in the up and down direction. A through-hole is formed in the center of the base 111, allowing the plunger 1363 to move up and down. The lower end of a support pillar 112 is fixedly provided at a portion closer to the periphery of the base 111 than the through-hole, and the lower end of a drive pillar 113 is rotatably supported relative to the base 111. The support pillar 112 and the drive pillar 113 each extend upward from the base 111.

[0018] A main motor support part 115 is fixed to the upper end of the support pillar 112. The upper end of the drive pillar 113 passes through the main motor support part 115 and is supported by the main motor support part 115 so as to be rotatable relative to the main motor support part 115. A pulley 117 is provided above the main motor support part 115 at the upper end of the drive pillar 113, coaxially positioned with the drive pillar 113, so as to be rotatable integrally with the drive pillar 113.

[0019] A main motor 116 is fixed to the main motor support part 115. The output shaft of the main motor 116 extends upward. An endless belt 118 is provided between the upper end of the output shaft and the pulley 117, looping them together. The rotational force of the main motor 116 is transmitted to the pulley 117 and the drive support 113 via the belt 118, causing the pulley 117 and the drive support 113 to rotate.

[0020] A vertical drive unit 114 is provided below the main motor support unit 115. A support pillar 112 slidably passes through an upper plate constituting the vertical drive unit 114, and the drive pillar 113 passes through a through-hole formed with an internal thread that screws into a male thread formed on the outer circumferential surface of the drive pillar 113 while the drive pillar 113 is threadedly engaged with the female thread. The vertical drive unit 114 is configured to move up and down as the drive pillar 113 rotates.

[0021] The upper plate of the vertical drive unit 114 is connected to the lower plate via the main load cell 121, and a member extends downward from the vertical drive unit 114 and is connected to the individual support unit 131. With this configuration, when the drive support column 113 is rotated by the rotational force of the main motor 116, the individual support unit 131 moves forward and backward together with the vertical drive unit 114 in the vertical direction, which is a predetermined direction.

[0022] A main load cell 121 is provided at the center of the upper and lower plates of the vertical drive unit 114. The main load cell 121 detects the value of the thrust force that is applied to the individual support unit 131 by the rotational force from the main motor 116 via the vertical drive unit 114 in the downward direction, which is the forward movement direction when the vertical drive unit 114 moves forward downward.

[0023] A plurality of rod-shaped members extend downward from the portion of the lower plate near the periphery toward the individual support portion 131 connected to the vertical drive portion 114, and rotatably support a pulley 134 having a rotation shaft 1361. A plurality of multi-motors 132-1, 132-2 are fixed to the individual support portion 131 connected to the vertical drive portion 114.

[0024] Although only two of the multiple multi-purpose motors 132-1, 132-2 are shown in Figure 1, eight are actually provided. Accordingly, eight plungers 1363, which are individually driven by these multi-purpose motors 132-1, 132-2, etc., are also provided and arranged in a ring shape when viewed from the axial direction of the plungers 1363. The sprues, runners, and gates 201 (see Figure 2) of the mold, into which the eight plungers 1363 are inserted one by one, are also arranged in a ring shape when viewed from the axial direction of the plungers 1363.

[0025] Due to the shape of the sprue, runner, and gate 201, the cull (hardened material) 301 (see Figure 3) formed in the sprue, runner, and gate 201 is smaller and shorter than the cull formed in a conventional sprue, runner, and gate.

[0026] 3, the cull 301 has a disk-shaped portion at the top and a conical portion at the bottom, and eight of these are molded, one for each plunger 1363, sprue, runner, and gate 201. By moving forward downward, the plunger 1363 can pump resin through the sprue, runner, and gate 201 into multiple cavities (not shown) of the mold.

[0027] The output shafts of the multi-purpose motors 132-1, 132-2 extend upward and pass through the individual support parts 131. A pulley 133 is provided at the upper ends of the multi-purpose motors 132-1, 132-2 in a coaxial positional relationship with the output shafts of the multi-purpose motors 132-1, 132-2 so as to be rotatable integrally with the output shafts of the multi-purpose motors 132-1, 132-2.

[0028] An endless belt 138 is provided to loop around the pulley 133, the upper end, and the pulley 134. The rotational force of the multi-motors 132-1 and 132-2 is transmitted to the pulley 134 and the rotary shaft 1361 via the belt 138, causing the pulley 134 and the rotary shaft 1361 to rotate.

[0029] A plunger support portion 1362 is provided below the individual support portion 131. A through hole is formed in the plunger support portion 1362 and has a female thread that screws onto a male thread formed on the outer circumferential surface of the rotating shaft 1361. The rotating shaft 1361 passes through the through hole and the male thread screws onto the female thread. The plunger support portion 1362 is configured to move up and down as the rotating shaft 1361 rotates.

[0030] Each of the plurality of plunger support portions 1362 is provided with a plunger 1363. The plunger 1363 is fixed to and supported by the plunger support portion 1362 so that the axis of the plunger 1363 is offset from the axis of the rotating shaft 1361.

[0031] With this configuration, as described above, the individual support section 131 moves up and down as the drive column 113 rotates due to the rotational force of the main motor 116, thereby supporting the plurality of plungers 1363 so that they can simultaneously move up and down. Furthermore, the rotational forces of the multi-motors 132-1 and 132-2 rotate the rotation shafts 1361, so that the plurality of plungers 1363 move up and down individually together with the plunger support section 1362.

[0032] A multi-purpose load cell 137 is provided at each connection portion where the plurality of plungers 1363 are connected and fixed one by one to the plunger support portion 1362. The multi-purpose load cell 137 detects the value of the thrust applied to the plunger 1363 via the plunger support portion 1362 by the rotational force from the multi-purpose motors 132-1 and 132-2 in the downward direction, which is the forward movement direction when the plunger support portion 1362 is moving downward.

[0033] The control device 150 is electrically connected to the main motor 116, the multi-motors 132-1 and 132-2, the main load cell 121, and the multi-load cell 137. For ease of explanation, Fig. 1 shows solid lines indicating that the control device 150 is electrically connected to the main motor 116 and the multi-motors 132-1 and 132-2, but does not show that the control device 150 is electrically connected to the main load cell 121 and the multi-load cell 137.

[0034] The control device 150 inputs from the main load cell 121 the value of the thrust that is imparted in the vertical direction by the rotational force from the main motor 116 to the individual support unit 131 via the vertical drive unit 114. The control device 150 also inputs from the multi-load cell 137 the value of the thrust that is imparted in the vertical direction by the rotational force from the multi-motors 132-1 and 132-2 to the plunger 1363 via the plunger support unit 1362. The control device 150 also controls the driving of the main motor 116 and the multi-motors 132-1 and 132-2.

[0035] Furthermore, the control device 150 can perform feedback control on each of the multi-motors 132-1, 132-2, in which the multi-load cell 137 applies a thrust that moves the multiple plungers 1363 forward in a downward direction relative to the individual support unit 131, and a feedback control that moves the multiple plungers 1363 backward in an upward direction, so as to eliminate differences in the thrust applied to the multiple plungers 1363, based on the thrust value from the multi-load cell 137. Furthermore, the control device 150 can perform feedback control on the main motor 116, in which the value of the thrust applied from the main motor 116 to the individual support unit 131 is adjusted, based on the thrust value from the main load cell 121.

[0036] Next, the control of the control device 150 will be described. First, the control device 150 drives the main motor 116 to rotate the drive support 113, thereby advancing the parts below the vertical drive unit 114 downward, specifically, the vertical drive unit 114, the individual support unit 131, the multi-motors 132-1 and 132-2, the plunger support unit 1362, the plunger 1363, etc., as shown by arrow A in FIG. 1. This causes the plunger 1363 to pump the resin material through the sprue, runner, and gate 201 into multiple cavities (not shown) of the mold. While the main motor 116 is being driven, the control device 150 performs feedback control to adjust the value of the thrust applied from the main motor 116 to the individual support unit 131 to an appropriate value based on the thrust value from the main load cell 121.

[0037] Furthermore, while plunger 1363 is pumping resin material through sprue, runner, and gate 201 to multiple cavities (not shown) of the mold in this manner, control device 150 performs feedback control to eliminate differences in thrust applied to multiple plungers 1363 based on thrust values ​​from multiple multi-purpose load cells 137. Specifically, control device 150 performs feedback control (see arrows B1 and B2 in FIG. 1 ) to apply thrust that causes multi-purpose motors 132-1 and 132-2 to move multiple plungers 1363 forward in the downward direction relative to individual support portion 131, and feedback control to apply thrust that causes multiple plungers 1363 to move backward in the downward direction, so that differences in thrust applied to multiple plungers 1363 are eliminated.

[0038] More specifically, when thrust is applied to the multiple plungers 1363, if the thrust exceeds a predetermined value in any of the multiple multi-load cells 137, the control device 150 performs feedback control to retract the plunger 1363 that has exceeded the predetermined thrust, thereby keeping the thrust below the predetermined value.

[0039] Conversely, when thrust is applied to multiple plungers 1363, if the thrust in any of the multiple multi-load cells 137 is significantly smaller than the predetermined thrust, the control device 150 performs feedback control to move the plunger 1363 that is exerting a thrust significantly smaller than the predetermined thrust forward more than the other plungers 1363, so that the thrust becomes closer to the predetermined thrust value.

[0040] According to the transfer molding machine 1 according to this embodiment having the above-described configuration, the following effects can be obtained.

[0041] The transfer molding machine 1 according to this embodiment includes an individual support section 131 that supports a plurality of plungers 1363 so that the plungers 1363 can simultaneously advance and retreat in a predetermined vertical direction, a main motor 116 as a main driving section that moves the individual support section 131 forward and retreat in the vertical direction, multi-motors 132-1 and 132-2 as a plurality of individual driving sections that individually move each plunger 1363 forward and retreat in the vertical direction relative to the individual support section 131, and a multi-motor 132-1, 132-2 that is provided on the individual support section 131 and detects the value of the thrust given to each plunger 1363 in the downward direction, which is the forward direction in the vertical direction. and a control device 150 as an individual control section that performs feedback control on each of the multi-motors 132-1, 132-2 to apply a thrust that moves the multiple plungers 1363 forward in the vertical direction relative to the individual support section 131 or a feedback control that moves the multiple plungers 1363 backward in the vertical direction based on the thrust value from the multi-load cell 137 so that there is no difference in the thrust applied to the multiple plungers 1363.

[0042] As a result, the multi-plunger type transfer molding machine 1 is realized using the multi-use motors 132-1, 132-2, the multi-use load cell 137, etc., and it becomes possible to fill each cavity with resin material at a uniform pressure with high precision in each plunger 1363. In particular, it becomes possible to fill each cavity with resin material at a uniform pressure with high precision without being affected by the measurement accuracy of materials such as resin material injected into the mold. It is also possible to prevent the configuration of the multi-plunger type transfer molding machine 1 from becoming too complicated.

[0043] Furthermore, by using a multi-plunger system for the transfer molding machine 1, the sprue, runner, and gate 201 can be made extremely small and simple, allowing for the size of the cull 301 molded therein. As a result, it is possible to reduce resin material loss, enabling material costs during mass production and disposal costs to be reduced. Furthermore, complex processing is no longer required to form the sprue, runner, and gate 201 in the mold, simplifying the mold structure. Furthermore, it is possible to simultaneously mold multiple parts with different amounts of resin using a single mold (cavity surface).

[0044] Furthermore, the multi-motors 132-1 and 132-2 serving as individual thrust detectors of the transfer molding machine 1 according to this embodiment are provided one for each of the plungers 1363. This makes it possible to easily realize a configuration in which each plunger 1363 is driven individually.

[0045] Furthermore, the multi-motors 132-1 and 132-2 serving as individual drive units of the transfer molding machine 1 according to this embodiment are configured by servo motors, which enable each individually driven plunger 1363 to be advanced and retreated with high precision.

[0046] Furthermore, the individual thrust detector of the transfer molding machine 1 according to this embodiment is configured with a load cell. This makes it possible to easily perform feedback control on the multi-motors 132-1 and 132-2 to apply a thrust that moves the multiple plungers 1363 forward in the vertical direction relative to the individual support part 131, or a feedback control to apply a thrust that moves the multiple plungers 1363 backward in the vertical direction, so that there is no difference in the thrust applied to the multiple plungers 1363.

[0047] Furthermore, the transfer molding machine 1 according to this embodiment is provided with a main load cell 121 as a main thrust detector that is provided on the individual support part 131 and detects the value of the thrust applied from the main motor 116, which serves as the main drive part, to the individual support part 131 in the forward direction in the vertical direction, and the control device 150, which serves as an individual control part, performs feedback control to adjust the value of the thrust applied from the main motor 116 to the individual support part 131 based on the thrust value from the main load cell 121.

[0048] This allows feedback control by the main motor 116 and the main load cell 121 in addition to feedback control by the multi-motors 132-1, 132-2 and the multi-load cell 137, making it possible for each plunger 1363 to fill each cavity with resin material at equal pressure with high precision.

[0049] The present invention is not limited to the above-described embodiment, and modifications are possible within the technical scope set forth in the claims. For example, the configuration of each part of the transfer molding machine is not limited to the configuration of the transfer molding machine 1 in this embodiment. Specifically, the individual support unit, main drive unit, individual drive unit, individual thrust detector, individual control unit, and main thrust detector are not limited to the individual support unit 131, main motor 116, multi-motor 132-1, 132-2, multi-load cell 137, control device 150, and main load cell 121 in this embodiment.

[0050] Furthermore, in this embodiment, eight plungers 1363 are provided, but this configuration is not limited thereto, and the number of plungers 1363 may be more or less than eight, as long as there are two or more. Furthermore, in this embodiment, feedback control is performed by the main motor 116 and the main load cell 121, but this is not limited thereto, and the main motor 116 may advance or retreat the vertical drive unit 114 and the individual support unit 131 downward or upward at a constant speed without performing feedback control. In this case, the main load cell 121 may not be provided.

[0051] Furthermore, in this embodiment, the transfer molding machine 1 is a multi-plunger type transfer molding machine 1 that simultaneously fills a thermosetting resin material into multiple cavities formed by multiple slots in a mold to perform molding, but the transfer molding machine 1 may also be a multi-plunger type transfer molding machine 1 that fills a thermosetting resin material into multiple locations in a single cavity to perform molding.

[0052] Specifically, the gate may be connected to multiple locations in one cavity, and by advancing downward, plunger 1363 may be able to pump resin through the sprue, runner, and gate to multiple locations in one cavity (not shown) of the mold.

[0053] In this case, in controlling the control device 150, the control device 150 first drives the main motor 116 to rotate the drive support 113, thereby advancing downward the parts below the vertical drive unit 114, specifically the vertical drive unit 114, the individual support unit 131, the multi-motors 132-1 and 132-2, the plunger support unit 1362, the plunger 1363, etc., as shown by arrow A in Figure 1.

[0054] As a result, each plunger 1363 pressurizes the resin material through the sprue, runner, and gate to multiple locations in one cavity (not shown) of the mold. While the main motor 116 is being driven, the control device 150 performs feedback control to adjust the value of the thrust applied from the main motor 116 to the individual support part 131 to an appropriate value based on the thrust value from the main load cell 121.

[0055] Furthermore, while plunger 1363 is pumping the resin material through the sprue, runner, and gate to multiple locations in one cavity (not shown) of the mold, control device 150 performs feedback control based on the thrust values ​​from multiple multi-load cells 137 so that a large difference occurs in the thrust applied to multiple plungers 1363.

[0056] Depending on the location of one cavity (not shown) of the mold, there are some areas that have a narrow shape and some areas that have a wide shape. When the area to be filled with resin material has a narrow shape, a higher thrust must be applied to the plunger 1363 when filling the resin material compared to when the area has a wide shape. This is because it is more difficult for the resin material to flow into and fill a narrow shape than a wide shape.

[0057] For this reason, specifically, the control device 150 increases the thrust applied to the plunger 1363 among the multiple plungers 1363 that fills the portion of the cavity having a narrow shape, and decreases the thrust applied to the plunger 1363 among the multiple plungers 1363 that fills the portion of the cavity having a wide shape.

[0058] In this way, in order to increase the difference in thrust applied to the multiple plungers 1363 and achieve a predetermined difference in thrust, the multi-motors 132-1 and 132-2 perform feedback control (see arrows B1 and B2 in Figure 1) to apply thrust that moves the multiple plungers 1363 forward in a downward direction relative to the individual support parts 131, and feedback control to apply thrust that moves them forward or backward in a downward direction.

[0059] Here, the "predetermined difference in thrust" means a difference in thrust that allows the resin material to be filled with high precision into both the narrow and wide portions of the cavity. The above configuration makes it possible to fill with high precision the resin material into both the narrow and wide portions of the cavity.

[0060] DESCRIPTION OF SYMBOLS 1 Transfer molding machine 116 Main motor (main drive unit) 121 Main load cell (main thrust detector) 131 Individual support unit 132-1, 132-2 Multi-motor (individual drive unit) 137 Multi-load cell (individual thrust detector) 150 Control device (individual control unit) 201 Sprue, runner, and gate 1363 Plunger

Claims

1. A multi-plunger type transfer molding machine having a plurality of plungers capable of pumping resin into a cavity through a sprue, runner, and gate of a mold, comprising: individual support parts supporting the plurality of plungers so that the plurality of plungers can be advanced and retreated simultaneously in a predetermined direction; a main drive part moving the individual support parts forward and backward in the predetermined direction; a plurality of individual drive parts moving each of the plungers individually forward and backward in the predetermined direction relative to the individual support parts; an individual thrust detector provided on the individual support parts and detecting the value of thrust applied to each of the plungers in the forward direction in the predetermined direction; and an individual control part performing feedback control on each of the individual drive parts so that the plurality of individual drive parts apply thrust to advance the plurality of plungers in the predetermined direction relative to the individual support parts or apply thrust to retreat the plurality of plungers in the predetermined direction based on the thrust value from the individual thrust detector, so that the difference in thrust applied to the plurality of plungers is eliminated or the difference in thrust applied to the plurality of plungers is increased.

2. A multi-plunger type transfer molding machine as claimed in claim 1, wherein said individual thrust detector is provided for each of said plurality of plungers.

3. A multi-plunger type transfer molding machine as described in claim 1, wherein said individual drive units are constituted by servo motors.

4. A multi-plunger type transfer molding machine as described in claim 1, wherein the individual thrust detector is constituted by a load cell.

5. A multi-plunger type transfer molding machine as described in claim 1, further comprising a main thrust detector provided on said individual support section for detecting the value of thrust applied from said main drive section to said individual support section in the forward direction in said predetermined direction, and said individual control section performs feedback control to adjust the value of thrust applied from said main drive section to said individual support section based on the thrust value from said main thrust detector.

6. A multi-plunger type transfer molding machine as described in claim 1, wherein the multiple plungers are capable of pumping resin into multiple cavities through a sprue, runner, and gate of a mold, and the individual control unit performs feedback control on each of the individual drive units to provide a thrust that advances the multiple plungers in the specified direction relative to the individual support units, or a feedback control to provide a thrust that retreats the multiple plungers in the specified direction, based on the thrust value from the individual thrust detector, so that there is no difference in thrust provided to the multiple plungers.

7. A multi-plunger type transfer molding machine as described in claim 1, wherein the multiple plungers are capable of pumping resin to multiple locations in one cavity through a sprue, runner, and gate of a mold, and the individual control unit performs feedback control on each of the individual drive units to provide a thrust that advances the multiple plungers in the specified direction relative to the individual support units, or a feedback control to provide a thrust that retreats the multiple plungers in the specified direction, based on the thrust value from the individual thrust detector, so that the difference in thrust provided to the multiple plungers becomes greater.

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