JP2744326B2 - Transfer molding method by fixing pot position and multi-plunger mold - Google Patents

Description

Description: BACKGROUND OF THE INVENTION (Industrial Application Field) The present invention relates to a transfer molding method by fixing a pot position to a plurality of types of lead frames and molding the same, and a multi-plunger die used for the method.

(Prior Art) FIG. 3 shows a schematic configuration of a conventional method of molding a lead frame by a transfer molding method.

In a transfer molding machine using a multi-plunger mold, the lead frame 12 is set on the mold with the pot 10 sandwiched therebetween, and the resin tablet contained in the pot 10 is melted.
The molten resin is extruded into the cavity to mold the lead frame 12.

The pots 10 are arranged one by one with respect to the package portions 14 facing each other, and are connected to the cavities of the lead frames 12 on both sides via the runners 16 from the pot 10.

Therefore, when the pitch of the package portions 14 of the lead frame 12 changes, the arrangement interval of the pots 10 also changes. FIG. 4 shows an example of a lead frame in which the pitch of the package portions 14 is narrower than that of FIG. 3. As the pitch becomes narrower, the arrangement interval of the pots 10 becomes narrower.

Since various sizes of products are provided for the lead frame 12 and the pitch of the package portion 14 and the like are also different, when molding these, the arrangement of the pots is set according to each lead frame, and the metal is arranged. Designing the mold.

(Problems to be Solved by the Invention) When a different type of lead frame is mounted on a conventional transfer molding machine, as described above, the pot arrangement and the like are different, so it is necessary to change the mold and the pot portion. is there.

Since the pot is provided with a plunger mechanism for extruding the resin, these mechanisms must be changed according to the pot arrangement.

In recent years, transfer molding machines have been increasingly automated, and the supply of resin tablets to the mold or the supply of lead frames to the mold has been fully automated. When a different type of lead frame is mounted, it is necessary to reassemble the entire surface including the transfer mechanism.

Therefore, there is a problem that when transferring different types of products to the transfer mold machine, the operation is very complicated and time-consuming.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a transformer with a fixed pot position that can be molded without changing the pot arrangement even when molding different types of lead frames. An object of the present invention is to provide a frame molding method and a multi-plunger die used for the method.

(Means for Solving the Problems) The present invention has the following configuration to achieve the above object.

In other words, in the transfer molding method in which a lead frame is set in a molding die and a resin tablet is supplied to a plurality of pots and molded, different pot frames having different pitches of a package portion are molded with a common pot position. While sharing the pot, supply the resin tablet only to the necessary pot,
It is characterized in that a mold for providing a resin path such as a runner or a branch path from a pot for supplying the resin tablet to the cavity is separately prepared and molded for different types of lead frames.

Further, in a multi-plunger mold for transfer molding having a mold for setting a lead frame and a pot for accommodating a resin tablet, the arrangement of the pot is common to different types of lead frames having different package unit pitches. A resin path such as a runner or a branch path from a pot for supplying a resin tablet is connected to the cavity in the molding die.

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

FIG. 1 is an explanatory view showing a method of molding a lead frame by a transfer molding method with a fixed pot position according to the present invention.

FIG. 1 shows a method of molding lead frames having different pitches of the package portions 14 while keeping the arrangement of the pots 10 the same.

That is, in the embodiment, molding is performed with the pitch D of the pot 10 being the same in both the case of FIG. 1 (a) and the case of FIG. 1 (b). The lead frame 20 shown in FIG. 1 (a) has a wider pitch of the package portion 14 than the lead frame 22 shown in FIG. 1 (b), and the pot 10 matches the lead frame 20 shown in FIG. 1 (a). To set the spacing.

Therefore, the package portions 14 correspond to the lead frames 20 one by one, but in the case of the lead frame 22 shown in FIG.
And the package unit 14 do not correspond one-to-one, and the package unit
The number of pots 10 is less than the number of 14.

In the lead frame shown in FIG. 1 (b), the runner 16 connected to the pot 10 is branched into two on the way and connected to the two package portions 14 through the branch path 16a to compensate for the shortage of the number of pots. .

The length of the resin path such as the runner 16 and the branch path 16a may differ depending on the pot 10 depending on the positional relationship between the pot 10 and the package portion 14. Since the same size resin tablets are used, if the length of the resin path such as the runner 16 is different, the injection volume of the molten resin is different. Therefore, in this case, the volume of the cull portion is changed so that the injection volume becomes constant.

In the case of the embodiment, four pots 14 are filled with resin from one pot 10, but it is not necessary to connect all the pots 10 and the package 14 in relation to the position and the number of arrangements of the package 14. In that case, an empty pot 10a that does not communicate with the cavity is provided. When supplying the resin tablet to the pot, the resin tablet is not supplied to the empty pot 10a.

FIG. 2 is an explanatory diagram showing a method of supplying the resin tablet 30 to the pot 10. The resin tablet is set in a mold together with the lead frame. The resin tablet and lead frame are aligned in advance on the supply side and gripped by the transfer unit in accordance with the mold pot arrangement and lead frame arrangement, and the transfer unit is moved parallel to the mold as it is and Supply lead frame.

Reference numeral 40 denotes a supporting portion for supporting the resin tablet 30 by the transfer portion. The supporting portion 40 is provided with a pocket 42 for accommodating the resin tablet 30 in conformity with the arrangement of the pot 10. Reference numeral 44 denotes a shutter that locks the bottom of the resin tablet 30 inserted into the pocket 42 and holds the resin tablet 30 from falling from the pocket 42. The resin tablet 30 is pushed up into the pocket 42 by the pusher, and is stored in the pocket 42 by closing the shutter 44.

With the resin tablet 30 stored in the pocket 42, the resin tablet 30 is carried along with the lead frame onto the mold, and after positioning, the lead frame is set on the mold and the resin tablet 30 is dropped into the pot 10. It is.

FIG. 2 (a) shows a case where the resin tablet 30 is stored in all the pockets 42 of the transfer section and the resin tablet is supplied to each of the pots 10; FIG. 2 (b) shows an empty pot 10a.
In this case, the resin tablet is supplied only to the necessary pot 10 without supplying the resin tablet 30. In the case of FIG. 2 (b), when inserting the resin tablet 30 into the pocket of the transfer portion, the resin tablet is controlled not to be inserted into the pocket 42a so that the resin tablet is not supplied to the empty pot 10a. I have to. In the example of FIG. 2A, four resin tablets are supplied, and in FIG. 2B, three resin tablets are supplied.

The method shown in FIG. 2 has the advantage that the arrangement of the pots 10 can be completely the same as that of the transfer section. By this method, the pot arrangement can be made common even when molding different types of lead frames, and a resin tablet can be appropriately supplied to the pot.

In this way, when resin-molding lead frames having different pitches of the package portion 14, it is possible to work with the pot arrangement and the transfer portion of the resin tablet in common.

A mold for resin-molding the lead frame is separately manufactured because it is necessary to form a cavity, a runner, and a gate in accordance with each lead frame. In this case, as described above, pot 10
Therefore, it is necessary to provide a design corresponding to each lead frame, such as providing a branch path in the runner.

In this way, if a mold with a common pot arrangement is manufactured, when switching to a different product, it is possible to easily switch by simply changing the mold and changing the control system. It can be simplified.

As mentioned above, in recent transfer molding machines, preheating of the resin tablet, alignment for supplying the resin tablet to the mold, etc. are all automated, and preheating etc. are also performed with the resin tablet aligned. The arrangement of pots in the mold has all affected the configuration of each part of the apparatus. The points that can be shared by the transfer molding machine by sharing the pot arrangement are as follows.

Common use of parts feeders for supplying resin tablets Common use of resin tablet alignment equipment Common use of resin tablet pre-heating equipment Common use of resin tablet transfer equipment Common use of cull check mechanism Common use of plunger Plunger equal pressure Common use of mechanisms As described above, common use of the pot arrangement allows common use of each part of the transformer frame molding machine, thereby greatly reducing the work required for product switching. The time can be shortened, and there is no need to prepare various kinds of parts for switching, and the cost is greatly improved.

As described above, the present invention has been described variously with reference to the preferred embodiments. However, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. That is.

(Effect of the Invention) According to the transfer molding method and the multi-plunger mold according to the present invention in which the pot position is fixed, it is possible to perform molding while keeping the pot position fixed for different types of lead frames. The trouble of replacing parts can be eliminated, and the switching operation can be performed very efficiently. Further, the versatility of the apparatus is improved, the number of parts for switching can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a transfer molding method by fixing a pot position according to the present invention, FIG. 2 is an explanatory view showing a transfer method of a resin tablet, and FIG. 3 and FIG. 4 are conventional lead frame molding methods. FIG. 10 ... pot, 10a ... empty pot, 12 ... lead frame, 14 ... package, 16 ... runner, 20, 22 ...
... lead frame, 30 ... resin tablet, 40 ... support, 42 ... pocket, 44 ... shutter.

Claims (2)

(57) [Claims] In a transfer molding method in which a lead frame is set in a mold and a resin tablet is supplied to a plurality of pots and molded, different types of lead frames having different pitches in a package portion are molded in a pot position. In addition to sharing a pot with a common pot, a resin tablet is supplied only to a necessary pot, and a resin mold such as a runner or a branch path is connected to a cavity from the pot to supply the resin tablet, and a mold provided with a different type is used. A transfer molding method by fixing a pot position, which is separately prepared and molded for a lead frame. 2. A multi-plunger mold for transfer molding having a mold for setting a lead frame and a pot for accommodating a resin tablet, wherein the pots are arranged for different types of lead frames having different package pitches. A multi-plunger mold, wherein a resin path such as a runner or a branch path is connected to a cavity from a pot for supplying a resin tablet to the mold.