JPH0525653B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a multi-plunger type transfer molding die used for sealing molding of electronic parts, and particularly to a molding pressure adjustment mechanism thereof.

[Conventional technology]

In a transfer mold, a pot for charging the molding material is formed on the upper surface of the lower mold, and the molding inside the pot is moved upward by a transfer plunger provided through the lower mold. Molding can be carried out by pressurizing the material to transfer and fill the molding material from the pot through the runner into each cavity.
In such transfer molding molds, if there is variation in the amount of molding material charged into the pot, there will be variation in the amount of molding material filled into the cavity, especially if the amount of molding material charged is excessive. If this is the case, excessive molding pressure will be applied to sensitive electronic components set in the cavity for sealing, and there is a risk that the electronic components will be damaged. Therefore, it has been considered to provide a molding pressure adjustment mechanism so that the molding pressure remains constant even if the amount of molding material input into the pot is excessive. 60-214916. In these devices, a molding pressure adjustment valve is provided in the upper mold at a position corresponding to the pot, and the molding pressure adjustment mechanism is activated by biasing the molding pressure adjustment valve with a predetermined pressure using a spring, oil pressure, etc. I'm trying to form it. When the amount of molding material input into the pot is excessive, the molding pressure adjustment valve moves back when the transfer plunger applies pressure, absorbing the excessive molding pressure and adjusting the molding pressure to a constant level. It is becoming more and more like this.

[Problem to be solved by the invention]

However, the above-mentioned Japanese Patent Application Laid-Open No. 60-149423 and
60-214916 is a device in which a molding pressure adjustment mechanism is formed in the upper mold by installing a molding pressure adjustment valve in the upper mold, and it is generally simple. There was a problem in that the structure of the upper mold, which can be formed into a similar structure, became complicated. The present invention has been made in view of the above points, and it is an object of the present invention to provide a transfer molding die in which a molding pressure adjustment mechanism can be provided without the need for complicating the structure of the upper mold. It is.

[Means to solve the problem]

The present invention provides a structure in which a transfer plunger 3 for pressurizing molding material is installed in a vertical hole 2 provided in a lower mold 1, and a portion of the vertical hole 1 above the upper end surface of the transfer plunger 3 is communicated with a cavity 4 for molding material. In a transfer molding mold formed as a charging pot 5, a resin reservoir 6 communicating with the pot 5 is provided in the lower mold 1, and a pressure adjustment hole 7 whose tip is open in the resin reservoir 6 is provided in the lower mold 1. It is characterized in that a molding pressure adjusting plunger 8 is installed in the mold 1 and in the molding pressure adjusting hole 7, and the molding pressure adjusting plunger 8 is urged toward the resin reservoir 6 side with a predetermined pressure. .

[Effect]

In the present invention, the lower mold 1 is provided with a resin reservoir 6 that communicates with the pot 5, and the lower mold 1 is provided with a molding pressure adjustment hole 7 whose tip is open in the resin reservoir 6. Since the molding pressure adjustment plunger 8 is installed in the adjustment hole 7,
A molding pressure adjustment mechanism consisting of a resin reservoir 6, a molding pressure adjustment hole 7, and a molding pressure adjustment plunger 8 can be incorporated into the lower mold 1, and the molding pressure adjustment mechanism can be attached to the upper mold 9. There will be no need.

【Example】

The present invention will be explained in detail below using examples. As shown in FIG. 1, the lower mold 1 is mounted on a lower mounting plate 16 via a spacer block 15, and vertical holes 2 are formed therein at a plurality of locations to penetrate vertically. A head portion 3a of a transfer plunger 3 is inserted into and attached to the vertical hole 2, and the lower end portion of the transfer plunger 3, which projects downward from the lower mold 1, is connected and fixed to a plunger drive plate 17. The upper part of the vertical hole 2, that is, the upper side of the upper end surface of the transfer plunger 3 is formed as a pot 5 that opens at the upper surface of the lower mold 1.
As shown in the figure, each pot 5 has runners 18, 18
It is arranged to communicate with a plurality of cavity recesses 19, 19, . . . via.... Also this runner 1
Ejector pins 20, 20... are provided through the lower mold 1 to correspond to the cavity recesses 19 and 8, and the lower ends of each ejector pins 20, 20... are connected and fixed to the ejector plate 21. It has been done. Further, the lower mold 1 is formed with a resin reservoir 6 that is open at the top and communicates with the pot 5 via a dummy runner 29, and a molding pressure adjustment hole 7 that is open at the bottom of the resin reservoir 6. It is bored in the lower mold 1. The lower part of the molding pressure adjustment hole 7 is formed as a biasing tool storage chamber 26, and by attaching the lower plate 30 to the lower surface of the lower mold 1, the lower end of the biasing tool storage chamber 26 is opened. It is set to close. A molding pressure adjustment plunger 8 is installed in the molding pressure adjustment hole 7, and a locking flange 25 formed at the rear end of the molding pressure adjustment plunger 8 is locked to the step 26a of the biasing tool storage chamber 26. It's like this. In addition, an elastic body 27 such as a spring is installed in the biasing device storage chamber 26 as a biasing means, and pushes the rear end of the molding pressure adjustment plunger 8 with a predetermined pressure to push the molding pressure adjustment plunger toward the resin reservoir 6 side. 8 is energized. As the biasing means, in addition to the elastic body 27 such as a spring, hydraulic pressure, pneumatic pressure, etc. can also be used. On the other hand, the upper mold 9 is attached to the upper mounting plate 22 and disposed above the lower mold 1, and the guide pin 23 protruding downward is inserted into the guide hole 2 of the lower mold 1.
The upper mold 9 and the lower mold 1 are clamped by being inserted into the upper mold 9 and the lower mold 1. By clamping the molds in this manner, the upper surface opening of the pot 5 and the upper surface opening of the resin reservoir 6 are closed on the lower surface of the upper mold 9, and a cavity 4 is formed in the cavity recess 19. be. By moving one or both of the lower mold 1 and the upper mold 9 up and down, the mold can be clamped and opened. In the transfer molding mold formed as described above, the mold is opened and the molding material 10 is poured into each pot 5, and then the mold is clamped, and the plunger drive plate 1 is connected to the hydraulic device using a connecting rod 28 or the like.
7 to move the transfer plunger 3 upward as shown in FIG.
0 is pressurized by the transfer plunger 3 and moves to the runner 1
8 to the cavities 4, and filling of each cavity 4 with the molding material 10 is started. At this time, a part of the molding material 10 in the pot 5 also flows into the resin reservoir 6 through the dummy runner 29. Then, the transfer plunger 3 is further moved upward to further transfer the molding material 10, and the molding material 10 is filled into the cavity 4 as shown in FIG. At this time, if the amount of molding material 10 charged into the pot 5 is too large, the molding pressure will exceed a predetermined pressure. It also affects. When this pressure exceeds the elastic force of the elastic body 27, the molding pressure adjustment plunger 8 retreats while compressing the elastic body 27, and the excess molding material 10 flows into the molding pressure adjustment hole 7. It is absorbed as shown in Figure 4. Therefore, it is possible to prevent abnormal molding pressure from being applied to each cavity 4, and prevent excessive molding from being applied to sensitive electronic components set in the cavity 4, such as when sealing electronic components. This can prevent damage caused by pressure. After the molding is completed, the mold is opened and the ejector plate 21 is operated to move the ejector pin 20 upward, and the molded product is ejected from the cavity recess 19 of the lower mold 1 and removed from the mold. I can do it.

【Effect of the invention】

As described above, in the present invention, the lower mold is provided with a resin reservoir that communicates with the pot, and the lower mold is provided with a molding pressure adjustment hole whose tip is open in the resin reservoir. A molding pressure adjustment plunger is attached inside the mold, and the molding pressure adjustment plunger is biased toward the resin reservoir with a predetermined pressure.By providing the resin reservoir and molding pressure adjustment hole in the lower mold, The molding pressure adjustment plunger can be installed in the lower mold, and the molding pressure adjustment mechanism can be incorporated in the lower mold,
There is no need to attach a molding pressure adjustment mechanism to the upper mold, and the structure of the upper mold can be simplified.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an embodiment of the present invention taken along line A-A in Fig. 2, Fig. 2 is a plan view of a part of the lower mold of the same, Figs. is A in Figure 2.
It is a cross-sectional view of the molded state of the same as the above cut along the line A. 1 is a lower mold, 2 is a vertical hole, 3 is a transfer plunger, 4 is a cavity, 5 is a pot, 6 is a resin reservoir, 7 is a molding pressure adjustment hole, 8 is a molding pressure adjustment plunger, 9 is an upper mold The mold 10 is a molding material.

Claims (1)

[Claims] 1. A transfer plunger for pressurizing the molding material is installed in the vertical hole provided in the lower mold, and a transfer plunger is formed in which the portion of the vertical hole above the upper end surface of the transfer plunger is formed as a pot for introducing the molding material into communication with the cavity. In the molding mold, a resin reservoir part communicating with the pot is provided in the lower mold, a pressure adjustment hole whose tip is open in the resin reservoir part is provided in the lower mold, and a molding pressure adjustment plunger is provided in the molding pressure adjustment hole. A transfer molding die characterized in that a plunger for adjusting the molding pressure is biased toward the resin reservoir side at a predetermined pressure.