JPS5842101Y2 - Floating structure of lower runner plate in mold die - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a floating structure of a lower runner plate in a mold.

As shown in FIG. 1, the lower runner plate 1 in a conventional molding die is tightly fixed in the longitudinal direction of the upper surface of the lower heat platen 2 by tightening bolts 3 or the like on both sides thereof.

Here, on both longitudinal sides of the lower runner plate 1, I
A lower mold chess block 5 in which a cavity 4 such as a C-mold is bored is supported on its lower surface by a floating bar 6 made of a hollow rod-shaped body, and is placed above the lower mold heat platen 2 with a slight gap 7 to form a floating structure. It is designed so that it can be moved up and down or tilted left and right to some extent.

The reason why the lower chess block 5 has a floating structure is because of the thickness of the lead frame such as an IC mold that is fitted between the lower chess block 5 and the upper chess block 8 clamped above it. Since there is uneven thickness, the difference in thickness of each lower chess block 5 is absorbed within the range of the above-mentioned gap 7, so that a specified pressing pressure is applied evenly to all the lower chess blocks in the mold. This is for the purpose of

In this case, the thickness of the lower runner plate 1 becomes a problem, but conventionally, the average value of the thickness of the lead frame described above for each loft is taken, and this average value is calculated from the thickness of the lower chess block 5. Based on the relationship, the thickness of the lower runner plate 1 was determined and so-called level adjustment was performed, such as by scraping off the bottom part.

If the level adjustment of this lower runner plate 1 is appropriate, the first
As shown in the figure, the lower chess block 5 and the upper chess block 8 and the lower runner plate 1 and the upper runner plate 9 are in close contact with each other, and a prescribed pressing pressure is applied to each lower chess block 5.

However, if the above level adjustment is incorrect, for example, if the thickness of the lower runner plate 1 is excessive, the specified press pressure will not be applied to each lower chess block 5, and an IC mold of desired quality will not be obtained. If the thickness of the lower runner plate 1 is small, or as shown in FIG. 2, a gap 10 is formed between the lower runner plate 1 and the upper runner plate 9, and the cavity is In some cases, the molding resin that should have flowed into the lower runner plate 4 leaked over the entire upper surface of the lower runner plate 1.

In any of the above cases, it was necessary to once remove the lower runner plate 1 from the lower heat platen 2 and adjust the level by scraping the bottom of the lower runner plate 1 or inserting a spacer.

The present invention was made to eliminate the above-mentioned drawbacks.
An object of the present invention is to provide a floating structure of a lower runner plate in a semiconductor encapsulation mold that does not require level adjustment of the lower runner plate.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the mold according to the present invention, as shown in FIG. Chess blocks 8 are arranged in two rows with their inner end surfaces in contact with both longitudinal sides of the upper runner plate 9.

A lower runner plate 1' is provided on the upper surface of the lower mold heat platen 2, which is provided opposite to the upper mold heat platen 11, corresponding to the position of the upper runner plate 9. A groove 12 is cut on the upper surface for feeding resin for molding an IC mold or the like into a cavity 4 formed in the upper surface of a lower chess block 5, which will be described later.

On both sides of the lower runner plate 1', there are lower chess blocks 5 with their inner end surfaces in contact with both longitudinal sides of the lower runner plate 1' and corresponding to the positions of the upper chess blocks 8. arranged in columns.

A plurality of cavities 4 for molding, such as an IC mold, are bored in the upper surface of the lower mold chess block 5, and a lower mold mounting plate 14 is formed on the lower surface thereof, passing through the lower mold heat platen 2 and the lower eject plate 13. It is supported by a floating cover 6.6, which is a hollow rod-shaped body interposed between.

This floating bar 6 is made slightly longer than the distance from the upper surface of the lower mold mounting plate 14 to the upper surface of the lower mold heat platen 3. Therefore, the lower mold chess block 5 is placed slightly above the lower mold heat platen 2. Gap 7 (see Figure 4)
It has a floating structure with an opening.

The floating structure of the lower runner plate 1' in the semiconductor encapsulation mold constructed as described above is as follows.
As shown in the figure, coaxially located through holes (L15 and 16) are drilled at appropriate locations below the lower runner plate 1' of the lower mold heat platen 2 and the lower eject plate 13.
Through the through holes 15 and 16, a floating bar 17, which is a hollow rod-like body that is slightly longer than the distance from the upper surface of the lower mold mounting plate 14 to the upper surface of the lower mold heat platen 2, is attached to the upper surface of the lower mold mounting plate 14 with its lower end surface. It is placed and inserted, and its upper end surface supports the lower surface of the lower runner plate 1'.

Here, since the upper end of the floating bar 17 slightly protrudes above the lower heat platen 2, a gap 18 is formed between the upper surface of the lower heat platen 2 and the lower surface of the lower runner plate 1'. It has a floating structure.

Therefore, the lower runner plate 1' can move vertically or tilt horizontally within this gap 18 to some extent.

In order to prevent the lower runner plate 1' from coming off upward, a stop bolt 20 is inserted into the through hole 19 penetrated through the plate thickness at an appropriate location, and the stepped portion at the lower end is inserted into the lower mold. It is screwed onto the top surface of heat platen 2.

Note that the reference numeral 21 is a disc spring installed in the bolt head of the stop bolt 20.

Since the present invention is constructed as described above, the lower runner plate 1' is also supported by the floating bar 17 in the same way as the lower chess block 5, so that it has a floating structure.
The lower runner plate 1' can also be moved up and down to some extent or tilted left and right within the gap 18 between it and the upper surface of the lower mold heat platen 2, and there is some variation in the level between the left and right lower mold chess blocks 5, 5. Even if there is, it can be absorbed and adhere well to the upper runner plate 9.

Therefore, the troublesome level adjustment of the lower runner plate, which is conventional, can be eliminated.

Further, since it is in close contact with the upper runner plate 9, resin can be prevented from leaking from the groove 12 onto the upper surface of the lower runner plate 1'.

Furthermore, the lower runner board 1' is the upper and lower chess block 5,
Since the adhesion of the lower chess blocks 8 to each other is not hindered, a specified pressing pressure is applied to each lower mold chess block 5, and an IC mold etc. of desired constant quality can be obtained.

Furthermore, the lower runner plate 1' has a floating bar 1
7, and tighten the stop bolts 2 at appropriate locations.
Since it is only latched at 0, the above stop bolt 20
It can be easily removed, replaced, and maintained by simply loosening it.

[Brief explanation of the drawing]

Figures 1 and 2 are side views of the main parts showing the mounting state of the conventional lower runner plate, Figure 3 is a cutaway perspective view of the main parts showing the molding die according to the present invention, and Figure 4 is the lower runner plate according to the present invention. FIG. 3 is a sectional view of a main part showing a floating structure of a runner plate. 1.1'...Lower runner plate, 2...Lower heat platen, 5...Lower chess block, 6.17...Floating bar, 7,18
...Gap, 8...Upper chess block, 9...Upper runner plate, 11...Upper heat platen, 13... Lower eject plate, 1
4...Lower mold mounting plate, 15.16...Through hole.

Claims (1)

[Scope of utility model registration request] an upper runner plate provided on the lower surface of the upper heat platen; upper chess blocks arranged in two rows with their inner end surfaces touching both longitudinal sides of the upper runner plate;
a lower runner plate for feeding molded resin provided on the upper surface of the lower mold heat platen corresponding to the position of the upper runner plate;
The inner end surfaces of the lower runner plates are in contact with both longitudinal sides of the lower runner plates, and are arranged in two rows corresponding to the positions of the upper chess blocks, and are supported by floating bars of hollow rod-like bodies, and are connected to the lower heat platen. In a mold having a lower chess block with a floating structure with a slight gap above, a floating bar is installed between the upper surface of the lower mold mounting plate and the lower surface of the lower runner plate to connect the lower heat platen and the lower ejector. A floating structure of a lower runner plate in a mold die, characterized in that the lower runner plate is supported by penetrating the plate and leaving a gap between the upper surface of the lower mold heat platen and the lower surface of the lower runner plate. .