JPH09155910A - Resin molding machine using motor driven press mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the mechanism by constituting a mold clamping mechanism and plunger driving mechanism by electric motor driven type, and constituting an isostatic unit by the drive of a hydraulic mechanism, thereby making it possible to accurately mold a resin. SOLUTION: A nut 52 is engaged with a threaded shaft 44, and is vertically moved by the rotation of the shaft 44 by a servo motor 40. Link plates 54a, 54b for connecting a base 34 and a movable platen 22 are engaged with the nut 52. The platen 22 is elevated by the vertical movements of the nut 52 to switch a mold. The driving mechanism of a plunger 16 is elevated together with the platen 22. A nut 62 is rotated by a servo motor 42, a threaded shaft 60 is vertically moved to lift the plunger 116 via a isostatic unit 80 and to squeeze pump the resin of a pot 12. A piston rod 82 is communicated by hydraulic oil, and respective plungers 16 are lifted by isostatic pressure. The unit 80 can be mounted from this side of the platen 22. Accordingly, accurate resin can be molded with a compact constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding device using an electric pressing mechanism.

[0002]

2. Description of the Related Art In a resin molding apparatus used for resin molding such as a lead frame used for electronic products, an automatic machine by transfer molding is widely used. The transfer molding apparatus clamps a lead frame of a molding target with a molding die, and pumps molten resin from the pot into the cavity with a plunger for resin molding.
The resin pressure by the plunger is high, and therefore the transfer molding apparatus is provided with a press mechanism for securely clamping the molded product so that resin leakage does not occur when the resin is pressure-fed.

As such a press mechanism, a hydraulic press mechanism has been widely used in the related art because a considerably high pressure is required, but in a clean room (class 10000 or so) since high precision electronic parts are handled. Therefore, an electric pressing mechanism that does not use hydraulic pressure has come to be used. A pressing device using an electric pressing mechanism having a servomotor or the like as a drive source may be driven by a lower mold in which a lower mold is movable or may be driven by an upper mold in which an upper mold is movable. FIG. 17 shows a conventional example of a resin molding apparatus using an electric press mechanism in which a lower die is movable (Japanese Patent Laid-Open No. 5-84766).

[0004]

As described above, the resin molding apparatus using the electric pressing mechanism has the advantage of not contaminating the working environment, and the resin injection speed can be controlled more easily than in the case of using hydraulic pressure. There is an advantage that the resin pressure can be accurately controlled. However, in the conventional example (for example, No. Kaikai 1-446208) that is configured by electric pressing in a resin molding device that uses a multi-pot type molding die that is widely used for manufacturing semiconductor devices, when the resin is pressure-fed from each pot. In order to equalize the resin pressure of, the spring pressure is used. However, in the method of utilizing the uniform pressure of the spring, when the resin amount of the resin tablet supplied to the pot varies, the resin pressure at the time of pumping the resin from each pot is different, which causes the cavity not to be filled or the resin pressure to be increased. There is a problem in that it is too high to cause flash and wire flow. On the other hand, the method of providing an equal pressure unit that equalizes the resin pressure sent from the pot by hydraulic pressure is completely equalized by the hydraulic pressure even if the resin amount of the resin tablets supplied to the pot varies. It is useful in that it is done.

As described above, in the resin molding apparatus, it is important to appropriately control the resin pressure at the time of resin molding to enable more accurate resin molding without voids, and at the same time, after resin molding, It is also important to properly release the resin molded product from the molding die so that it can be carried out. Especially in the case of products such as the recent resin mold type semiconductor devices where the thickness of the resin molding part is extremely thin, defects are more likely to occur due to improper release operation. More precise control is required for the mold release operation.

It should be noted that resin mold type semiconductor devices tend to be thinned, the amount of resin used is reduced, a high quality resin mold free from voids is required, and mass productivity is required. In a resin molding apparatus used for manufacturing a product, a lower plunger method in which a plunger is installed in a lower die is used and a multi-pot type molding die (called a lower multi-plunger method) is generally used. In the device that arranges the plunger in the upper mold, it is necessary to pull out the plunger upward from the pot every time the resin is pumped from the pot, so that it is easy for air to be trapped in the pot and a void is easily generated. However, there is a problem that the cycle time of the resin mold cannot be shortened due to cooling.

The present invention has been made in order to solve the above-mentioned problems in a resin molding apparatus using such a lower multi-plunger system, and prevents the resin pressure from varying due to the pot during resin molding, thus providing a stable resin. In addition to enabling molding to enable high-precision resin molding, the form of the press mechanism can be made compact and a large mold clamping force can be easily obtained.
An object of the present invention is to provide a resin molding device using an electric pressing mechanism that enables an efficient configuration as a resin molding device.

[0008]

The present invention has the following constitution in order to achieve the above object. That is, a mold clamping mechanism by a lower mold drive for clamping the molded product, a plunger drive mechanism by a lower multi-plunger system for pumping the resin supplied to the pot, and an equal pressure to the plunger when pumping the resin. In the resin molding apparatus having an adding equal pressure unit, the mold clamping mechanism and the drive mechanism of the plunger are driven by an electric motor, and the equal pressure unit is driven by a hydraulic mechanism. Further, the mold clamping mechanism is constituted by a toggle mechanism driven by an electric motor. In addition, a drive mechanism for the plunger supports a screw shaft that supports an equal pressure unit arranged below the lower pot, a nut that engages with the screw shaft, and the nut is rotated to move the screw shaft up and down. It is characterized by comprising an electric motor for driving. Further, the equal pressure unit is installed in the movable platen. Further, the equal pressure unit is mounted in the movable platen so as to be insertable and removable from a side surface thereof.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. FIG. 1 is a plan view showing the overall configuration of a lead frame transfer molding apparatus as an embodiment of a resin molding apparatus using an electric press according to the present invention. This transfer molding apparatus is a lower multi-plunger apparatus, and is an apparatus for automatically resin-molding by supplying a lead frame on which a semiconductor chip is mounted and a resin tablet.

In the figure, the portion A is a portion for supplying a lead frame on which a semiconductor chip is mounted, the portion B is a portion for setting the lead frames in parallel and setting them so as to face each other, and C
The portion is a portion for supplying the resin tablet, the portion D is a portion for arranging the resin tablets in alignment, the portion E is a portion for resin-molding the lead frame, and the portion F is for unnecessary resin adhered to the lead frame after the resin molding. The digating portion and the G portion are portions for accommodating and accommodating the lead frames after the digging.

In the resin molding apparatus of this embodiment, an electric press mechanism using a servo motor as a drive source is adopted as a mold clamping mechanism at the E portion where the lead frame is clamped and resin-molded. In the figure, 10 is a molding die mounted on the press machine, and 12 is a pot provided on the lower die 10a of the molding die 10. This resin molding device is a pot 12
It is a device for taking four sheets in which two rows are arranged. In order to supply the lead frame and the resin tablet to the molding die 10, the resin tablet and the lead frame are chucked by the in-loader at the portion B, the in-loader is moved in parallel on the molding die, and the lead frame is set on the lower die 10a. Is performed by setting a resin tablet in the pot 12. Therefore, in the portion B, the resin tablet is arranged in the same arrangement as the pot 12 of the molding die 10, and the lead frame is arranged in the same arrangement as the set portion of the lead frame in the molding die 10.

After the lead frame and the resin tablet are set, the lead frame is clamped by the molding die 10 by the pressing mechanism, and the resin melted in the pot 12 is pressure-fed to the cavity by the plunger to mold the resin. After resin molding, the mold is opened, the unloader is advanced from the F side onto the molding die 10, and the lead frame after resin molding is chucked and returned to the F side.
After degating, the molded product is stored in the G part. In this way, the lead frame can be supplied from the A portion and the resin tablet can be supplied from the C portion to continuously and automatically perform resin molding.

FIG. 2 shows the state of the press mechanism of the E portion as seen from the front side, and FIG. 3 shows the state as seen from the right side. The present press mechanism is a lower die driving press device in which the upper die side is fixed and the lower die side is movable. 20 is a fixed platen, 22 is a movable platen, and 24 is a base. The upper die 10b is fixed to the fixed platen 20, and the lower die 10a is fixed to the movable platen 22. Reference numeral 80 denotes an equal pressure unit for equalizing the resin pressure fed from each pot. The equal pressure unit 80 has a communication passage through which pressure oil is fed and a piston rod on which hydraulic pressure acts. FIG. 2 shows that the piston rod projects upward. A portion H indicates a hydraulic mechanism that communicates with the constant pressure unit.

In FIG. 3, reference numeral 40 is a servomotor for clamping the mold for moving the movable platen 22 up and down, and 42 is a servomotor for pushing the plunger. As shown in the figure, the servomotor 40 for clamping the mold is arranged on the back side of the press machine, and the servomotor 42 for pushing the plunger is arranged on the right side surface of the press machine. As described above, the resin molding apparatus according to the present embodiment is characterized in that the drive mechanism for clamping the press mechanism and the electric motor as the drive source for pushing the plunger are used, and the hydraulic mechanism is used for the equal pressure unit. .

(Mold Clamping Mechanism) FIGS. 4 and 5 show a mold clamping mechanism in the press machine. FIG. 4 shows the press apparatus as seen from the front side, and FIG. 5 shows the state as seen from the right side. FIG. 5 shows the mold open state on the left side of the center line and the mold clamped state on the right side. FIG. 4 corresponds to the mold clamped state. The press mechanism of the present embodiment is configured such that the base 24 and the movable platen 22 are linked by a link (toggle mechanism), and the link is driven by the servo motor 40 to open and close the mold.

As shown in FIG. 5, the servomotor 40 and the screw shaft 44 rotatably erected in the center of the base 24 are a pulley 46 fixed to the lower end of the screw shaft 44 and an output shaft 48 of the servomotor 40. Belt 50 is put between them and they are connected. A nut 52 is screwed onto the screw shaft 44, and the screw shaft 44 moves up and down by rotating around the axis. A link connecting the base 24 and the movable platen 22 is engaged with the nut 52, and the movable platen 22 is moved up and down as the nut 52 moves up and down, thereby opening and closing the mold.

In this embodiment, the link connecting the base 24 and the movable platen 22 has the first, second and third links.
It is composed of one link plate 54a, 54b, 54c. These first, second, and third link plates 54a, 54b, and 54c are arranged in pairs in parallel when viewed from the front as shown in FIG. 4, and at a symmetrical position sandwiching the screw shaft 44 as shown in FIG. To do. The second link plate 54b is attached to the base 24 by the shaft 55.
One end of the third link plate 54c is pivotally supported by the movable platen 22 by the shaft 56, and the second plate 5 is supported.
The other end of 4b and the other end of the third link plate 54c are axially supported by a shaft 57. As a result, the shaft 57 serves as a fulcrum
The link plate 54b and the third link plate 54c can be bent.

The first link plate 54a has a nut 52 at one end.
And is pivotally supported by the second link plate 54b at the other end. The second link plate 54b of the first link plate 54a
The shaft support position at is an intermediate position between the shaft 55 and the shaft 57. The first link plate 54a acts as a drive link that transmits the driving force due to the vertical movement of the nut 52 to the second link plate 54b and the third link plate 54c. Thus, by rotating the screw shaft 44 by the servo motor 40, the nut 52
And the first, second, and third link plates 54a, 54b, 5
The movable platen 22 moves up and down via 4c to open and close the mold.

FIG. 6 shows the movable platen 22 as viewed from above. As shown in the figure, the link of this embodiment pivotally supports the third link plate 54c by the shaft 56 at a substantially central portion in the width direction of the movable platen 22, so that the mold clamping force is applied to the mold die 10.
There is an advantage in that the left and right chase set to can be surely acted in a well-balanced manner and the molded product can be reliably clamped and resin-molded. In addition, since the toggle mechanism is used in the present embodiment, a large pressing force can be obtained with a small motor, and the present invention can be suitably applied to a resin molding apparatus that requires high output.
Further, the mold can be clamped at high speed without increasing the output of the motor, the entire device can be made compact, and the mold clamping mechanism is configured to push both ends of the movable platen 22, so that the center of the lower part of the movable platen 22 can be reduced. It has an effect that a drive transmission system can be arranged in the section.

As a pressing device using an electric pressing mechanism, there is an example in which a screw press is used as a conventional example (actual cutting flatness).
1-46208). The screw press has high accuracy of stop position when opening the mold, the pressure is constant regardless of the height position,
Although it has advantages such as high holding force, it has a slow speed, a motor with a large output must be used, the surface pressure on the screw thread is high, and the screw is easily worn. There is a problem that the parallel balance of the movable platen is poor. Comparing a pressing device using a toggle mechanism with a pressing device using a screw press, there is a problem that the mold clamping force varies when the height position of the movable platen changes during mold clamping. In this respect, in the pressing device of the present embodiment, the mold thickness of the mold to be mounted on the movable platen 22 is set to be common to different kinds of products, and the mold clamping position is not changed when the kinds are switched. Thereby, a constant mold clamping force can be always obtained by using the toggle mechanism. When the mold clamping mechanism is configured by the electric press mechanism in this way, the pressure detected by the servo motor is actually detected by using a sensor such as a load cell, and the detected value is fed back to the servo motor for high speed and real time operation. It becomes possible to control speed and pressure.

(Plunger drive mechanism) As described above, after the mold is clamped, the plunger for pumping the molten resin from the pot to the cavity is driven by a servomotor different from the servomotor 40 for clamping. By the motor 42.
7 and 8 show the drive mechanism of the plunger driven by the servo motor 42. The plunger drive mechanism moves up and down together with the movable platen 22 when the movable platen 22 moves up and down by the mold clamping mechanism, and pushes the plunger in the mold clamped state to pump the resin. The figure shows the movable platen 22 and the drive mechanism portion of the plunger attached thereto.

The lower die 10a is fixed to the movable platen 22, and the pot 12 and the chase 14 provided with a recess for setting the molding target are mounted on the lower die 10a. The top of the plunger 16 is inserted into the pot 12 so that the plunger 16 is vertically movable in the pot 12. The resin molding apparatus of this embodiment is a four-piece type in which two chase 14 are set on the lower mold 10a. Therefore, it is necessary to provide a plunger drive mechanism for each chase 14.

Since a plurality of pots 12 are provided in the chase 14 in the multi-pot type resin molding apparatus, one plunger 16 is provided for each chase 14 in each pot 12.
When the cavity is mounted and the cavity is filled with the resin, these plungers 16 are pushed to pressure-feed the resin from all the pots 12. The above-mentioned equal pressure unit is a mechanism that allows the resin to be filled with a uniform resin pressure when the resin is pressure-fed by the plurality of plungers 16 as described above, even if the resin amount of each resin tablet varies. 80 in FIGS.
Indicates this isobaric unit. In this embodiment, the constant pressure unit 80 equalizes the resin pressure by hydraulic pressure, and the plunger 16 is supported by the piston rod 82 extending from the constant pressure unit 80.

The plunger 16 is driven by the plunger 1
This is done by pushing the pressure equalizing unit 80 that supports 6. As described above, in this embodiment, the chase 14 is used.
As shown in FIG. 7, the equal pressure unit 80 is attached to each chase 14 and the resin is filled. As a method of driving the plunger 16 up and down, that is, a method of driving the equal pressure unit 80 up and down, in the present embodiment, a screw shaft 60 is provided at the bottom of each equal pressure unit 80, and a nut 62 is screwed onto the screw shaft 60. Then, a configuration is adopted in which the nut 62 is rotated by the servo motor 42.

The connection between the servo motor 42 and the nut 62 is made by passing a belt 66 between the output shaft 64 of the servo motor 42 and the nut 62. A tension roller 68 adjusts the tension of the belt 66. FIG. 6 shows a plan view in which the belt 66 is hooked between the output shaft 64 and the nut 62.

A screw shaft 60 and a nut 62 are provided for each chase 14 as shown in FIGS.
By rotating the nut 62 by the screw shaft 60
Moves up and down, which drives the plunger 16 via the equal pressure unit 80. The resin molding operation is performed by clamping the product to be molded by the mold clamping mechanism, and then pushing up the plunger 16 by driving the servo motor 42 to pressure-feed the resin supplied to the pot 12.

The drive mechanism of the plunger of this embodiment is provided with a drive unit such as a screw shaft 60 and a nut 62 for each chase 14. When the drive mechanism is provided for each chase 14 as described above, the resin for each chase 14 is provided. There is an advantage that the pumping is reliable. For example, if the plunger 16 of each chase 14 is pushed up in common by one screw shaft, the pushing force is biased to one side. In this respect, in this embodiment, the chase 1 on one side is used when the production is reduced.
Even when resin molding is performed with only 4 or when different types of products are resin molded with the left and right chase 14, reliable resin molding is possible. In this embodiment, one servo motor 42
Although the nuts 62 and 62 are commonly driven by the above, separate servo motors may be used for each nut 62. Also,
The hydraulic circuit of the equal pressure unit 80 that obtains a uniform pressure by the hydraulic pressure described later may be independently provided for each chase.

Reference numeral 70 in FIG. 8 indicates an ejector rod. The ejector rod 70 is for ejecting the ejector pin from the inner surface of the cavity when the mold is opened.
When the mold is opened, it abuts on the lower surface of the ejector pin plate arranged in the lower mold 10a. Reference numeral 72 is a rod mounting plate, which is fixed in advance at a predetermined height position of the pressing device. The ejector rod 70 is mounted so as to penetrate the movable platen 22 in the mold opening / closing direction. When the movable platen 22 descends as the mold is opened, the lower surface of the ejector pin plate abuts the ejector rod 70, and the movable platen 22 further moves.
Is moved downward, the upper end surface of the ejector rod 70 projects from the upper surface of the movable platen 22 and acts to push up the ejector pin plate.

(Replacement Structure of Isobaric Unit) The isobar unit is for pushing up the plunger 16 by a uniform pressure when pushing up the plunger 16 by the drive mechanism of the plunger. 9 shows a sectional view of the equal pressure unit, FIG. 10 shows a perspective view of the equal pressure unit, and FIG. 11 shows an assembled perspective view of the equal pressure unit. As described above, the equal pressure unit 80 of the present embodiment obtains a uniform pressure. It uses hydraulic pressure for this. FIG.
Reference numeral 84 is a multi-block for feeding pressure oil, and reference numeral 82a is a piston head slidably mounted in the multi-block 84. FIG. 12 is a cross-sectional view showing the internal structure of the multi-block 84, showing how the piston rod 12 is communicated with the pressure oil. Since the piston rod 12 is communicated with the pressure oil, each plunger 16 is pushed up by a uniform pressure when the equal pressure unit 80 is pushed up by the drive mechanism of the plunger.

Since the equalizing unit 80 sets the plunger 16 according to the arrangement of the pots 12 in the molding die 10, it is separately manufactured corresponding to the molding die 10. Therefore, when the product type is switched by the resin molding device, the isostatic unit 80 must be replaced as a set together with the chase of the molding die 10, especially the chase.
Since the equal pressure unit 80 is arranged inside the movable platen 22 below the plunger 16, the replacement of the equal pressure unit 80 at the time of changing the type becomes a very complicated work.

As described above, the equal pressure unit 80 of the present embodiment does not disassemble the device inside the movable platen 22 in order to facilitate the replacement work at the time of switching the product type, and the equal pressure is applied from the front side of the movable platen 22. It is characterized in that the unit 80 can be inserted and removed to be mounted. 4 and 7 show the state in which the movable platen 22 is viewed from the front side of the front side. As shown in the figure, the movable platen 22 is attached with an equal pressure unit 80 in accordance with the position of the plunger 16 attached to the molding die 10. Mounting holes 90, 90 for penetrating in the front-rear direction, and the equal pressure unit 80 is mounted in the mounting hole 9
It was constructed so that it could be attached and detached by inserting into and removing from within 0 and 90.

Inside the mounting holes 90, 90, a multi-plate 85 for inserting and removing the equal pressure unit 80 is fixed to the upper part of the screw shaft 60 in parallel with the longitudinal direction of the mounting hole 90. The mounting holes 90, 90 ensure a space in the vertical direction so that the multi-plate 85 can be moved up and down by the driving mechanism of the plunger. Since the equal pressure unit 80 is positioned and mounted on the multi plate 85 by inserting and removing, the groove 84a is provided on the outer surface of the multi block 84, and the T groove 85a provided on the upper surface of the multi plate 85 is engaged with the groove 84a. The block 84 can be engaged. FIG.
0 shows the state where the multi-block 84 is engaged with the multi-plate 85.

Since hydraulic pressure is required to communicate with the multi-block 84 and the multi-block 84 is fixed to the multi-plate 85, in the present embodiment, as shown in FIG. The bracket 86 was fixed, and the hydraulic communication bracket 87 was fixed to the front part of the multi-block 84. FIG. 11 shows the fixing bracket 8
6 shows the assembly of 6 and the hydraulic communication bracket 87. The fixing bracket 86 is simply fixed to the front part of the multi-plate 85, and the hydraulic communication bracket 87 is fixed by being communicated with the hydraulic hole 84b provided in the multi-block 84. To attach the multi-block 84 to the multi-plate 85, the multi-block 8 is inserted into the T groove 85a of the multi-plate 85 with the hydraulic communication bracket 87 fixed to the multi-block 84.
4 is inserted.

Multi block 84 on multi plate 85
Is inserted, the position of the multi-block 84 in the width direction and the vertical direction is regulated. Positioning of the hydraulic communication bracket 87 and the multi-block 84 is performed by inserting the positioning pin 87a between the hydraulic communication bracket 87 and the fixing bracket 86 in a state where the multi-block 84 is mounted on the multi-plate 85. Multi block 8
Whether or not No. 4 has been set to the regular position is confirmed by confirming this positioning pin by the sensor 89. An oil feed pipe 88 is connected to the hydraulic communication bracket 87 via a one-touch coupler to connect the equal pressure unit 80 and the hydraulic mechanism. In FIG. 11, reference numeral 86a is an escape hole for passing the ejector rod 70 described above.

In FIG. 13, the multi-block 84, the multi-plate 85, and the fixing bracket 8 in the movable platen 22.
6. A multi-block 84, which shows a plan view of a state in which the hydraulic fluid communication bracket 87 is attached, enters the central portion of the movable platen 22 and is attached on the multi-plate 85.
The hydraulic communication bracket 87 is fixed to the front portion of the multi-block 84, the hydraulic communication bracket 87 is positionally regulated in the front-rear direction by a positioning pin 87a, and the multi-block 84 has a groove 84a and a multi-plate 85 has a T groove 85a. The lateral direction of 84 is regulated and positioned.

FIG. 14 shows a state in which the equal pressure unit 80 mounted on the movable platen 22 is viewed from the front side. The hydraulic communication bracket 87 is mounted on the fixing bracket 86, whereby the multi-block 84 is fixedly supported. The figure shows a state in which the equal pressure unit 80 is in a lower position and a state in which it is in an upper position (phantom line). 89 is a positioning pin 8
7a is properly set, and the hydraulic communication bracket 87, that is, the equal pressure unit 80 is attached to the mounting hole 9
It is detected whether or not it is set to the regular position within 0.
If the multi-block 84 is not in the proper position, the molding die may be damaged, so that it is provided to prevent an erroneous operation.

The equal pressure unit 80 is the molding die 1
Finally, the attachment is completed by connecting with the plunger 16 of 0. When inserting / removing the equal pressure unit 80, the piston rod 8
2 is performed without mounting the plunger 16. That is,
The connection between the constant pressure unit 80 and the plunger 16 is performed by setting the constant pressure unit 80 at a predetermined position of the movable platen 22 and setting the lower die 10a at a predetermined position of the movable platen 22, and then setting the plunger 16 from above the pot 12 into a pot. 12
It is done by inserting it inside.

The plunger 16 is connected to the tip of the piston rod 82 of the equal pressure unit 80 as shown in FIG.
This connection method is based on a conventionally known method (actual Kaihei 3-26519).
issue). As shown in FIG. 9, a holder 92 for connecting the plunger 18 by key engagement is provided at the tip of the piston rod 82.
Is provided, and the lower end of the plunger 16 is inserted into the holder 92 and the plunger 16 is rotated around the axis to immovably engage the plunger 16 and the piston rod 82 in the axial direction. When the plunger 16 is removed from the holder 92, the key engagement can be released by rotating the plunger 16 in the opposite direction to that when the plunger 16 is installed, and the plunger 16 can be pulled out and removed. To attach and detach the plunger 16, move the isobaric unit 80 to the uppermost position,
It is performed with the upper end of the plunger 16 protruding from the pot 12.

Since the piston rod 82 and the plunger 16 of the equal pressure unit 80 are detachably attached as described above, the equal pressure unit 80 can be inserted into and removed from the mounting hole 90 from the side surface of the front portion of the movable platen 22. It becomes possible to set it in a predetermined position. The suction holes 90 have a purpose of reducing the weight of the movable platen 22 while making the movable platen 22 thick in order to prevent the movable platen 22 from warping. The equal pressure unit 80 can be mounted on the movable platen 22 using the mounting hole 90. As described above, according to the resin molding apparatus of the present embodiment, the isobaric unit 80 can be replaced very easily, and the work for changing the product type, which has conventionally been complicated, can be facilitated.

As described above, the resin molding apparatus of this embodiment uses the electric pressing mechanism by the servomotor as the mold clamping mechanism and the driving mechanism of the plunger, and the resin pressure when the resin is pressure-fed from each pot is as follows. It uses the uniform pressure by hydraulic pressure, and by appropriately utilizing the advantages of the electric press mechanism and the hydraulic mechanism, it is possible to obtain the highest molding conditions at present as the whole device. The mold clamping and plunger drive mechanism can be controlled with higher accuracy and speed than with hydraulic pressure, and can be controlled without shock when changing pressure or speed, and the equal pressure mechanism can use hydraulic mechanism to obtain perfect equal pressure. I have to.

In the equal pressure unit 80, the resin pressure can be made uniform, and the resin pressure can be easily set by adjusting the oil pressure, so that the resin pressure can be easily controlled while the plunger is operating. You can Normally, the hydraulic pressure set by the equal pressure unit 80 is set to a high pressure at the time of starting the resin injection, causing the plunger to act like a rigid body and quickly melting the resin tablet to optimize the injection speed when the resin passes through the gate. Control. Then, just before the cavity is filled with the resin, the uniform pressure is changed to a highly accurate molding pressure (low pressure) so that water hammer is prevented and light flash does not occur.

Generally, the uniform pressure by the constant pressure unit 80 is set to be lower than the main transfer pressure. The magnitude of the pressure applied to the equal pressure unit 80 and the switching timing of the pressure are set individually for each product. At that time, the product is actually resin-molded and the wire flow, voids, etc. are checked and optimally controlled. To do so. Even when different kinds of products are resin-molded, the equal pressure unit 80 can be commonly used when the intervals between the pots of the molding die and the number of the plungers are the same, and it is possible to deal with them only by changing the setting of the uniform pressure. .

The resin molding apparatus of the present embodiment enables extremely high precision resin molding at the time of molding, as described above, but it is also possible to control the mold releasing operation after molding with high precision as described below. Therefore, more accurate resin molding becomes possible. The mold release of the product after resin molding is performed by protruding the ejector pin from the bottom surface of the cavity as described above. At this time, in the pot 12 portion, the resin remaining in the pot 12 is simultaneously pushed up by the plunger 16 in the pot 12 portion. FIG. 15 is an enlarged view of an operating portion for releasing the resin after molding. 100 is a molded product such as a lead frame, 102 is a resin molded product, 104 is a cull, and 110 is an ejector pin.

At the end of resin molding, a little resin remains in the pot 12, and the resin is in contact with the upper end surface of the plunger 16 (in FIG. 15, the plunger 16 is in contact with the cull 104). Therefore, the plunger 16
When pushing up 4, the plunger 16 is once lowered to separate the resin from the plunger 16, and the plunger 16 is pushed up again to push out the cull 104.
The operation of the plunger 16 is based on the driving mechanism of the plunger driven by the servo motor 42.
When lowering 6, the position (upper position) where the plunger 16 was in contact with the resin is stored, and after the plunger 16 is returned to this storage position, the resin molded product 102 is pushed out simultaneously with the cull 104. Control. The plunger drive mechanism moves the equal pressure unit 80 up and down to push the plunger 16, and storing the upper position of the plunger 16 actually means storing the upper position of the equal pressure unit 80.

During the operation of lowering the plunger 16 once, at the same time, the mold opening by the mold clamping mechanism is performed, and the mold opening is stopped once the mold is almost fully opened and the lower mold 10a is opened.
A discharge hand is inserted between the upper mold 10b and the upper mold 10b. In this state, the plunger 16 returns to the upper position, and the mold is opened again to the final lowered position. By the mold opening at this time, the ejector pin 110 is projected from the inner surface of the cavity of the lower mold 10a, and at the same time, the cull 104 is projected by the plunger 16.

The operation of operating the plunger 16 can be controlled much more accurately because it is performed by the servo motor 42 than when hydraulic pressure is used, and the mold clamping mechanism is also driven by the electric motor, so that the operation of pushing out the plunger 16 is completely timed. It is possible to project the ejector pin 110 by making them coincide with each other. In particular, in the present embodiment, the equal pressure unit 80 is made to have a uniform pressure by hydraulic pressure, so that when the plungers 16 are returned to the upper position, the plungers 16 in the respective pots 12 correspond to the amount of resin remaining in the pots 12. Will return to the original position. That is, when the constant pressure unit 80 is returned to the upper position by the drive mechanism of the plunger, the plunger 16 automatically returns to the upper position according to the resin amount of each pot 12 by the uniform hydraulic pressure.

Comparing the mold releasing operation according to the present embodiment with the method of using the uniform pressure by the spring for the equal pressure unit, when the spring uniform pressure is used, the flexure of the spring is different if the amount of resin remaining in the pot is different. Therefore, the pushing force from the pot varies, and the timing of pushing the cull out of the pot is displaced.On the other hand, when an equal pressure unit with uniform hydraulic pressure is used, the pushing force from the pot can be made uniform. This has the advantage that the timings can be perfectly matched. Plunger 1
Extrusion of cull 104 by 6 and ejector pin 110
If the timing of extruding the resin molded product 102 due to the deviation occurs, the problem that the cured resin breaks at portions other than the gate portion occurs, and the problem that excess resin remains in the resin molded product 102 occurs, so it is extremely useful as a releasing operation. is important.

In the actual device, the lower mold 10a and the upper mold 1
0b is provided with a holding jig for holding the cull 104 and the resin molded product 102 on the lower die 10a from above, and the plunger 16 and the ejector pin 110 are used for releasing the die. The cull 104 and the resin molded product 102 are released while being pressed. This is because if the amount of cull 104 remaining in the pot 12 varies,
Although the push-out start timing by the plunger 16 is the same, the push-out end timing from the pot 12 is shifted by the pot 12 and the release of the pot 1 is completed.
This is to prevent the mold release resistance from disappearing and the plunger 16 to be projected as it is.

In the above releasing operation, the ejector pin 110 is arranged at the cavity position when the resin molded product 102 is released from the cavity, and the resin molded portion is ejected by the ejector pin 110.
However, if it is not appropriate to eject the resin-molded portion with the ejector pin, such as when molding a very thin package with resin, place the ejector pin 110 on the molding target 100 such as a lead frame. It may touch and stick out. FIG. 16 shows a configuration in the case where the ejector pin 110 is brought into contact with the article to be molded 100 and is released. The protrusion operation of the plunger 16 and the ejector pin 110 is exactly the same as that described above. In the figure, the plunger 16 is once lowered and the cull 104 and the plunger 16 are separated.

As described above, when the ejector pin 110 is directly contacted with the article to be molded 100 in a thin package and released from the mold, the installation position of the ejector pin 110 is determined by the length accuracy of the ejector pin 110. It is set at a position slightly lower than the lower surface of the product 100 (about 0.5 mm). Therefore, the pushing operation by the ejector pin 110 needs to be accurately controlled in consideration of the installation position of the ejector pin 110.
Since the extrusion is controlled by, the mold release operation requires considerably high precision control. Such control can be reliably performed by using a mold clamping mechanism driven by an electric motor and a drive mechanism of a plunger, as compared with a hydraulic mold clamping mechanism, and by using an equal pressure unit utilizing uniform hydraulic pressure. It will be possible to do it more completely.

[0051]

As described above, according to the resin molding apparatus using the electric pressing mechanism according to the present invention, it is possible to easily obtain the resin molding apparatus having a large mold clamping force in the apparatus having a compact structure. In addition, the mold clamping mechanism and the drive mechanism of the plunger are driven by an electric motor,
By driving the equal pressure unit with a hydraulic mechanism,
By combining the advantages of electric drive and hydraulic drive, it is possible to enable highly accurate resin molding. Further, since the equal pressure unit can be inserted and removed from the side surface of the movable platen to be mounted, the work of exchanging the molding die and the equal pressure unit can be facilitated and the workability can be improved when the product type is changed. It is very effective.

[Brief description of the drawings]

FIG. 1 is a plan view showing an overall configuration of a resin molding device according to the present invention.

FIG. 2 is a front view of a pressing mechanism of a resin molding device.

FIG. 3 is a right side view of a pressing mechanism of the resin molding device.

FIG. 4 is a front view of a mold clamping mechanism of the press mechanism.

FIG. 5 is a side view of a mold clamping mechanism of the press mechanism.

FIG. 6 is a plan view of a mold clamping mechanism and a drive mechanism of a plunger.

FIG. 7 is a front sectional view showing a drive mechanism of a plunger.

FIG. 8 is a side sectional view of a drive mechanism of the plunger.

FIG. 9 is a sectional view of an equal pressure unit.

FIG. 10 is a perspective view showing a state in which an equal pressure unit is mounted on a multi plate or the like.

FIG. 11 is an assembled perspective view of mounting the equal pressure unit on a multi-plate or the like.

FIG. 12 is a cross-sectional view showing a configuration inside a multi-block.

FIG. 13 is a plan view of the movable platen in which an equal pressure unit is mounted.

FIG. 14 is a side view of the movable platen in which an equal pressure unit is mounted.

FIG. 15 is a cross-sectional view showing an operation of releasing a resin molded product and cull by a resin molding device.

FIG. 16 is a cross-sectional view showing a releasing operation of a resin molded product and cull by a resin molding device.

FIG. 17 is a partial cross-sectional view showing the configuration of a conventional example of a resin molding device using an electric motor.

[Explanation of symbols]

 10 Mold Die 10a Lower Die 10b Upper Die 12 Pot 14 Chase 16 Plunger 20 Fixed Platen 22 Movable Platen 24 Base 40 Servo Motor 42 Servo Motor 44 Screw Shaft 50 Belt 52 Nut 54a First Link Plate 54b Second Link Plate 54c Third link plate 60 Screw shaft 62 Nut 66 Belt 70 Ejector rod 80 Equal pressure unit 82 Piston rod 84 Multi block 84a Groove 85 Multi plate 85a T groove 86 Fixing bracket 87 Hydraulic connecting bracket 87a Positioning pin 88 Oil pipe 90 Mounting Hole 92 Holder 100 Molded product 102 Resin molded product 104 Cull 110 Ejector pin

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication // B29L 31:34

Claims (5)

[Claims] 1. A mold clamping mechanism by a lower mold drive for clamping a molded product, and a plunger drive mechanism of a lower multi-plunger system for pressure-feeding resin supplied to a pot.
In a resin molding apparatus having an equal pressure unit that applies uniform pressure to the plunger when pressure-feeding resin, the mold clamping mechanism and the drive mechanism of the plunger are driven by an electric motor, and the equal pressure unit is driven by a hydraulic mechanism. A resin molding device using an electric pressing mechanism. 2. The resin molding apparatus using the electric pressing mechanism according to claim 1, wherein the mold clamping mechanism is a toggle mechanism driven by an electric motor. 3. A drive mechanism of a plunger, a screw shaft supporting an equal pressure unit disposed below a pot of a lower mold, a nut screwed to the screw shaft, and the screw shaft rotating the nut. 3. A resin molding apparatus using an electric press mechanism according to claim 1, further comprising: an electric motor for driving up and down. 4. A resin molding apparatus using an electric pressing mechanism according to claim 1, 2 or 3, wherein the equal pressure unit is installed in a movable platen. 5. A resin module using an electric press mechanism according to claim 4, wherein the equal pressure unit is mounted in the movable platen so that the side surface of the unit can be inserted and removed.