JPS5852106Y2 - Transfer molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer molding machine, and more particularly to a device for shortening the curing time of the cull portion of a molded product.

The prior art will be explained using FIGS. 1 and 2.

First, a resin tablet 1 is put into a pot 2 as shown in FIG.

Then, the resin tablet 1 is heated and softened by heaters built into the upper mold 4 and the lower mold 5, and is lowered from outside the mold and inserted into the pot 2 so as to be fit into the upper mold 4. ．． The runner 6° cavity 7 formed by the lower die 5 is filled with the runner, resulting in a state as shown in FIG.

Note that a plunger drive section (not shown) is installed on the upper frame 8.

Upper mold 4. The lower mold 5 is maintained at a temperature at which the resin is cured (the mold temperature is 150 to 200° C.) by a built-in heater, a thermocouple, and an external temperature controller (not shown).

Therefore, the resin in the cavity 7 and runner 6 is cured after a certain period of time.

However, since the plunger 3 does not have a heat source, in the elevated state as shown in FIG. 1, the room temperature is 100° C. or more lower than the mold temperature, so it is cooled by the outside air.

In order to insert the resin tablet 1 and clean the molds 4 and 5, the plunger 3 must be left out of the pot 2 as shown in Figure 1 for usually 1 to 2 minutes, and the temperature of the bottom surface 9 of the plunger is lower than the mold temperature. It is about 20℃ lower.

Therefore, when curing the resin in the state shown in Figure 2, the molded product cull 10 is in contact with the low-temperature plunger bottom 9, so curing is poor, and a long curing time is required to fully cure the cull portion 10, resulting in molding. The drawback was that it was less efficient.

An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a transfer molding machine that can cure the cull of a molded product in a shorter time and shorten the curing time.

In order to achieve the above object, the present invention provides a heat cylinder that heats the bottom of the plunger at the raised position of the plunger, thereby preventing the temperature of the bottom of the plunger from being cooled by the outside air and accelerating the hardening of the cal. This is what I did.

Hereinafter, the present invention will be illustrated by an embodiment shown in FIG. 3 (with the plunger raised) and FIG. 4 (with the plunger lowered).

In each figure, the same numbers as in FIG. 1 indicate the same parts.

Reference numeral 11 denotes a heating cylinder with a built-in heater and thermocouple, and is connected to a temperature regulator 13 by a lead wire 12, and the heating cylinder 1 can be maintained at about the mold temperature (150 to 250°C). , is fixed to the upper frame 8.

The inner diameter of the heating cylinder 1 and the outer diameter (usually 40 to 5 Q mm) of the plunger lower part 9 are designed to fit together movably.

In addition, the heat cylinder 1 and the plunger 3 are connected to each other by the heat insulator 14.
This prevents the heat from affecting the hydraulic drive unit (not shown).

The upper mold 4 and the lower mold 5 have built-in heaters and thermocouples, and are maintained at the mold temperature by an external temperature controller (not shown), so that the resin filled in the runner 6 and cavity 7 is cured. ing.

According to this embodiment, even if the plunger 3 is raised to clean the pot 2 or to put the resin tablet 1 into the pot 2, the lower part 9 of the plunger 3 is inside the heat cylinder 1, so that it is exposed to outside air. It is not cooled, and the temperature of the bottom surface 9 of the plunger is approximately the mold temperature.

Therefore, put resin tablet 1 into pot 2,
When the plunger 3 that fits into the pot 2 is inserted from outside the mold and the plunger 3 fills the runner 6 and cavity 7 with resin, that is, when the state as shown in FIG. is cavity 6, runner 7
Because it is surrounded by walls kept at the mold temperature, that is, the surface of the upper mold 4, the surface of the lower mold 5, and the plunger bottom surface 9,
The cull part 10 also hardens in about the same time as the resin in the runner part and cavity part.

That is, the conventional problem that the cull 10 hardens more slowly than the resin in the cavity and runner parts is eliminated, the curing time can be shortened, and the molding efficiency can be improved.

For example, in the case of acid-curing resin A, the mold temperature is 170
Conventionally, it took 150 seconds to harden the cull at 170 DEG C., but by using the present invention and keeping the heat cylinder at 170 DEG C., it now takes only 80 seconds to harden the cull.

In other words, the curing time was reduced to 70 seconds.

As explained in detail above, according to the present invention, a temperature-controlled heat cylinder for keeping the lower part of the plunger warm is provided.
Since the plunger is arranged in a raised position, the cull part of the molded product in transfer molding can be cured quickly, the curing time can be shortened, and the molding efficiency of transfer molding can be improved, so it can be used for transfer molding such as resin molded semiconductors. It is effective in improving the productivity of manufactured products and reducing costs.

Furthermore, according to the present invention, even if the transfer molding cycle is accelerated, the cull is reliably cured, uncured resin adheres to the bottom of the plunger and inside the pot, and enters the sliding surface of the pot and plunger, reducing resistance. This has the effect of preventing the occurrence of unfilling, pinholes, etc. due to insufficient injection pressure due to increase in the amount of resin or entering into the runners and gates, thereby making it possible to seal the IC with resin with high reliability.

[Brief explanation of drawings]

FIGS. 1 and 1 are diagrams showing parts related to resin curing of a conventional transfer molding machine, in which FIG. 1 shows a state in which the plunger is raised, and FIG. 2 shows a state in which the plunger is lowered. 3 and 4 are views showing one embodiment of the transfer molding machine of the present invention, in which FIG. 3 shows a state in which the plunger is raised, and FIG. 4 shows a state in which the plunger is lowered. 3...Plunger, 9...Bottom of plunger, 10...Cal, 11...
・Heat cylinder.

Claims (1)

[Scope of utility model registration request] A plunger is placed above the mold to fit into the pot of the upper mold, and after the resin tablet is put into the pot of the upper mold, the plunger is fitted into the pot of the upper mold from outside the mold. By lowering the
This is a transfer molding machine that heats and softens a resin tablet placed in a pot, and injects the softened resin into each cavity through a runner in a mold. The plunger is fixedly disposed, the plunger is insulated by a hydraulic drive unit and a heat insulator, and the heat cylinder and the lower part of the plunger are in contact with each other, so that heat is conducted to the lower part of the plunger to keep it warm. Transfer molding machine.