JPH0525652B2 - - 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 to keep the molding pressure constant even if the amount of molding material input into the pot is excessive.
It is provided in Publication No. 149423 and Japanese Patent Application Laid-open No. 60-214916. These products are equipped with a molding pressure regulating valve in the upper mold at a position corresponding to the pot.
A molding pressure adjustment mechanism is formed by biasing the molding pressure adjustment valve with a predetermined pressure using a spring, oil pressure, or the like. 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 has a molding pressure adjustment mechanism formed in the upper mold, which has the problem of complicating the structure of the upper mold, and it cannot be used with existing molds. There was a problem in that it was difficult to modify the mold and provide a molding pressure adjustment mechanism. The present invention has been made in view of the above points, and provides a transfer molding mold that does not make the mold structure complicated and that makes it easy to provide a molding pressure adjustment mechanism to an existing mold. The purpose is to

[Means to solve the problem]

The present invention is characterized in that a transfer plunger 3 for pressurizing the molding material that is moved up and down with respect to the lower mold 1 is installed in a vertical hole 2 provided in a lower mold 1, and a In a transfer molding mold in which the upper part is formed as a molding material injection pot 5 that communicates with the cavity 4, a vertical hole 6 for molding pressure adjustment that opens at the upper end surface of the transfer plunger 3 is inserted into the transfer plunger 3 along its axis. The molding pressure adjusting plunger 7 is vertically movably mounted in the vertical hole 6 for molding pressure adjustment, and the molding pressure adjusting plunger 7 is urged upward with a predetermined pressure. It is something.

[Effect]

In the present invention, a molding pressure adjustment vertical hole 6 is formed in the transfer plunger 3 for pressurizing the molding material 8 charged into the pot 5, and a molding pressure adjustment plunger is formed in the molding pressure adjustment vertical hole 6. 7, the molding pressure adjustment mechanism can be incorporated into the transfer plunger 3, and in order to form the molding pressure adjustment mechanism, the mold, especially the upper mold, has a complicated structure. There is no need to do this.

【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. In addition, the transfer plunger 3 has a vertical hole 6 for adjusting molding pressure which is opened vertically through the center of the axis of the transfer plunger 3.
is formed, and a molding pressure adjustment plunger 7 is installed in the vertical hole 6 for molding pressure adjustment. While the locking flange 25 formed at the rear end of the molding pressure adjustment plunger 7 is locked to the step 26a of the biasing tool storage chamber 26 formed at the rear end of the molding pressure adjustment vertical hole 6, the molding pressure is adjusted. The tip surface of the head portion 7a at the tip of the adjustment plunger 7 is flush with the tip surface of the head portion 3a of the transfer plunger 3. An elastic body 27 such as a spring is installed in the biasing device storage chamber 26 as a biasing means, and presses the rear end of the plunger 7 with a predetermined pressure to elastically bias the plunger 7 toward the pot 5 side. be. As a 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 mold in this manner, the upper surface opening of the pot 5 is closed by the lower surface of the upper mold 9, and the cavity recess 19 is closed.
The cavity 4 is formed in this portion. 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 8 is poured into each pot 5, and then the mold is clamped, and the plunger drive plate 17 is connected to the hydraulic device using a connecting rod 28 or the like.
When the transfer plunger 3 is moved upward as shown in FIG. The filling of the molding material 8 is started. Then, the transfer plunger 3 is further moved upward to further transfer the molding material 8, and the molding material 8 is filled into the cavity 4 as shown in FIG. At this time, if the amount of molding material 8 charged into pot 5 is too large, the molding pressure will exceed a predetermined pressure, but if this pressure exceeds the elastic force of elastic body 27, the effect of this pressure will cause The molding pressure adjusting plunger 7 retreats while compressing the elastic body 27, and the excess molding material 8 is absorbed into the molding pressure adjusting vertical hole 6 as shown in FIG. 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. The molding pressure adjustment mechanism formed by the molding pressure adjustment plunger 7 and the like is incorporated in the transfer plunger 3 provided in the lower mold 1 in order to pressurize and transfer the molding material 8 in the pot 5. Therefore, a molding pressure adjustment mechanism can be provided in the transfer molding die without the need for major modification of the transfer molding die (particularly the upper mold 9). 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, a vertical hole for adjusting molding pressure that opens at the upper end surface of the transfer plunger is formed in the transfer plunger along its axial direction, and a vertical hole for adjusting molding pressure is formed in the vertical hole for adjusting molding pressure. The plunger is attached so that it can move up and down, and the molding pressure adjustment plunger is biased upward at a predetermined pressure, so if too much molding material is put into the pot and the molding pressure exceeds the predetermined pressure, Due to the action of this pressure, the molding pressure adjustment plunger retreats and excess molding material is absorbed into the molding pressure adjustment vertical hole, thereby preventing abnormal molding pressure from being applied within the cavity. Moreover, the molding pressure adjustment mechanism formed by a molding pressure adjustment plunger, etc. is provided in a transfer plunger attached to the lower mold to pressurize and transfer the molding material in the pot, A molding pressure adjustment mechanism can be provided in a molding die using a transfer plunger without complicating the structure of the mold.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is a plan view of a part of the lower mold of the same as above, Figs.
The figure is a sectional view of the same molded state as above. 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 molding pressure adjustment vertical hole, 7 is a molding pressure adjustment plunger, 8 is a molding material, 9 is an upper mold It is.

Claims (1)

[Claims] 1 A molding device in which a transfer plunger for pressurizing the molding material that is moved up and down with respect to the lower mold is installed in a vertical hole provided in the lower mold, and a portion above the upper end surface of the transfer plunger in the vertical hole is communicated with the cavity. In a transfer molding mold formed as a material input pot, a vertical hole for adjusting molding pressure that opens at the upper end surface of the transfer plunger is formed in the transfer plunger along its axial direction, and a vertical hole for adjusting molding pressure is formed in the transfer plunger along its axial direction. A transfer molding die characterized in that a molding pressure adjusting plunger is attached to the molding pressure adjusting plunger so as to be movable up and down, and the molding pressure adjusting plunger is biased upward with a predetermined pressure.