JP3198131B2 - Molding device with centering mechanism for resin tablet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus having a centering mechanism for a resin tablet.

[0002]

2. Description of the Related Art A transfer molding apparatus is used for manufacturing a resin mold type IC product. This transfer molding device sets the lead frame at a predetermined position on the molding die, supplies a resin tablet, which is a resin material for molding, into the molding die pot, heats and melts the resin tablet in the pot, and melts it with a plunger. The resin is molded by forcing the resin into the cavity. A commonly used resin tablet is obtained by solidifying a resin in a small columnar shape, and is supplied into a pot by being gripped by a chuck. The diameter and the like of the resin tablet are set according to the amount of resin required for resin molding.

[0003]

By the way, when supplying a resin tablet to a pot, the resin tablet is gripped to the pot position and then dropped into the pot. Also 1mm
~ 2mm smaller for easier loading. in this way,
As a result of making the resin tablet smaller in diameter than the pot diameter, when the resin tablet is supplied into the pot, the resin tablet may shift in the pot by the clearance between the pot and the resin tablet.

FIG. 4 shows a state in which a lead frame is being transfer-molded and is being filled with resin. In the figure, 10 and 11 are lead frames, 12 is a pot for extruding the resin, and 13 is a resin filled in the cavity. In this example, the resin is filled into the lead frames on both sides from one pot. Looking at portions A and B in the figure, there is a large difference in the degree of resin filling into the cavity between the portions A and B. ing. One cause of the difference in the degree of filling of the resin into the cavity is that when the resin tablet is set in the pot, the resin tablet is not correctly set at the center position, but is set off from the center.

[0005] In recent years, since packages have become thinner, molding conditions for lead frames have become considerably strict, and conditions for uniform molding have become narrower. For this reason,
When the resin tablet is displaced in the pot as described above, there is a problem that a molding failure occurs or a condition varies every molding, so that a non-defective product cannot always be manufactured under a constant condition. Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to enable a resin tablet to be accurately set at the center of a pot in a transfer molding machine, thereby reducing molding conditions. An object of the present invention is to provide a molding apparatus having a centering mechanism for a resin tablet, which can be made uniform and can produce good products under a certain condition.

[0006]

To solve the above-mentioned problems, the present invention has the following arrangement. That is, a resin tablet is supplied to the pot, and the resin tablet is pressed and melted by a plunger, and the resin is fed into the cavity by pressure.
In the molding machine performed , the resin tablet is
Insert the outer shape of the resin tablet into the
Upright to support the resin tablet
A concave portion, and a resin tablet on the outer peripheral edge of the concave portion inside the concave portion.
And a taper guide set at the center position.
It is characterized by that. Also, set the resin tablet
The resin placed on the cull portion in the concave portion of the lower cull portion
A projection that fits into the fitting recess provided on the end face of the tablet
Is provided . Furthermore, a resin tab
The resin tab is provided on the pressing end face of the plunger for pressing the let.
A projection that fits into the fitting recess provided on the end face of the
Vignetting wherein the are. It is also installed on the lower mold
The resin tablet is supplied to the pot, and the resin tablet is
The resin is pressed and melted with a plunger, and the resin is pressed into the cavity.
In a molding device where resin is sent to
Pressing end face of plunger that receives resin tablet in slot
Into the fitting recess provided on the end face of the resin tablet
The protrusion is provided . Also,
The tablet is supplied with a resin tablet.
The resin is pressed and melted by the plunger, and the resin is pumped into the cavity.
Plunge in a molding machine where resin molding is performed
Press the spherical resin tablet on the pressing end face of the
Receiving hemispherical recess is formed.
You .

[0007]

When the resin tablet is set in the pot by providing a setting mechanism for the resin tablet in the molding die or the plunger of the molding apparatus, the resin tablet is set at the center of the pot. By positioning the resin tablet at the center of the pot, when filling the cavity with the resin, the resin is filled evenly to one side, and uniform resin filling is performed. As a result, the molding conditions are made uniform, and a good product can be manufactured effectively.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an example in which a setting mechanism for positioning a resin tablet at the center of a pot is provided on a cull portion of a molding die. In the figure, reference numeral 20 denotes a cull portion of the mold, and a concave portion 24 for positioning the resin tablet 22 is provided on the upper surface of the mold. Resin tablet 2
2 is a generally used cylindrical shape, and the concave portion 24 has the same outer diameter and size as the resin tablet 22, and has a circular planar shape. The upper peripheral portion of the concave portion 24 is notched obliquely to provide a tapered guide portion 26 for guiding and receiving the resin tablet 22 into the concave portion 24. The cross-sectional shape of the cull portion of the molding die is, therefore, a straight portion 24 that supports the outer periphery of the resin tablet 22 from the inner bottom surface of the concave portion 24.
a rises and becomes a shape spread by the tapered guide portion 26 at the edge portion.

In the case of the molding apparatus of this embodiment, the resin tablet 24 is guided by a taper guide 26 by dropping the resin tablet 24 from above the cull portion 20 into a molding die, and the lower portion of the resin tablet 22 enters the recess 24. And the center of the resin tablet 22 can be aligned with the center of the pot. By accurately positioning the resin tablet 22, when the plunger 28 feeds the molten resin, the resin can be uniformly pumped, and each cavity can be uniformly filled with the resin. When the corners of the resin tablet 22 are chamfered as shown in FIG. The method for setting the resin tablet of the present embodiment can be used as it is without changing the shape of the conventional resin tablet, and it is only necessary to form a concave portion in the cull portion of the mold on the molding device side, and to change the plunger and the like. There is an advantage that there is no need.

FIG. 2 shows a method of aligning the resin tablet with the center of the pot by providing fitting recesses 22a and 22b on both end surfaces of the resin tablet 22.
a, 22b and projections 20a provided on the cull portion 20 of the mold
This is an example in which projections 28a provided on the pressing end surface of the plunger 28 are fitted to each other to perform positioning. The protrusions 20a, 28a and the fitting recesses 22a, 22b are provided in the same shape so as to fit into the concave and convex, and when the resin tablet 22 is set, the fitting recesses 22a, 22b and the projections 20a,
The resin tablet 22 is positioned by fitting 28a. At the time of resin molding, the resin tablet 22 is transferred so that one end surface of the resin tablet 22 is placed on the cull portion 20 of the molding die as shown in the figure, and the fitting concave portion 22a and the projection 20a are fitted to raise the resin tablet 22 upright. Let the plunger 28
The resin is filled by pressing the other end surface of the resin tablet 22 with.

Also in this embodiment, since the resin tablet is positioned at the center of the pot, uniform resin filling is possible. Although the embodiment shown in FIG. 2 is an example in which the plunger is arranged in the upper mold, the same applies to the case where the plunger is arranged in the lower mold. In this case, when the resin tablet is stored in the pot, the protrusion 28a provided on the pressing end surface of the plunger is fitted into the fitting concave portion of the resin tablet 22 so that the resin tablet can be set at the center of the pot. Note that FIG.
In the case of the type shown in FIG.
There is an advantage that when the resin is filled with the fitting concave portion 22a of the resin tablet 22, the air is less entangled and the resin can be suitably filled.

FIG. 3 shows an example in which a resin tablet is centered in a pot by using a spherical resin tablet 22 to perform resin molding. Spherical resin tablet 2
In order to center 2, the pressing end surface of the plunger 28 is formed in a hemispherical shape according to the curvature of the resin tablet 22, and the cull portion 20 is formed in a hemispherical shape. When the resin tablet 22 is dropped into the pot, it is supported by the center of the plunger 28 and automatically aligned. In the case of this embodiment, the resin can be uniformly filled by receiving the resin tablet at the center of the pot, and the resin tablet 22 is tightly stored in the plunger 28 and the cull portion 20 so that the air at the time of filling the resin is improved. There is an advantage that the entanglement is reduced and that the pressing force applied to the resin tablet 22 during resin filling is uniformly applied.

[0013]

According to the molding apparatus with a centering mechanism for a resin tablet according to the present invention, as described above, the resin tablet is set at the center of the pot when the resin tablet is supplied to the pot during resin molding. Since the resin is filled, it is possible to prevent the resin from being unevenly filled in the cavity, and it is possible to manufacture a high quality product by uniformly filling the resin. In addition, the quality of the product can be made constant, and it becomes easy to use a resin or the like under severe molding conditions. In addition, by making the resin filling uniform, it is possible to absorb errors such as variations in the weight of the resin tablet, etc.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a method of setting a resin tablet in a molding device.

FIG. 2 is an explanatory view showing another method for setting a resin tablet in a molding device.

FIG. 3 is an explanatory view showing still another method of setting a resin tablet in a molding device.

FIG. 4 is an explanatory view showing a state in which a lead frame is filled with resin.

[Explanation of symbols]

 10, 11 Lead frame 12 Pot 20 Cull part 20a Projection 22 Resin tablet 22a, 22b Fitting recess 24 Recess 24a Straight portion 26 Taper guide 28 Plunger

Claims (5)

(57) [Claims] 1. A molding apparatus in which a resin tablet is supplied to a pot, and the resin tablet is pressed and melted by a plunger, and the resin is pressed into a cavity to perform resin molding. In the cull part of the mold ,
The resin formed according to the external size of the resin tablet
A recess for supporting the tablet in an upright position;
Set the tablet to the center position in the recess.
A molding device with a centering mechanism for a resin tablet, characterized in that the molding device is provided with a guide portion . 2. A lower mold for setting said resin tablet.
The resin tablet placed on the cull
Projections that fit into the fitting recesses on the end face of the
2. The molding device according to claim 1, wherein the resin tablet has a centering mechanism. 3. A plunge for pressing said resin tablet.
Provided on the end face of the resin tablet.
3. The molding device with a centering mechanism for a resin tablet according to claim 2, wherein a projection fitted into the fitting recess is provided . 4. A resin tablet in a pot provided in a lower mold.
And the resin tablet is pressed and melted with a plunger.
The resin is melted and the resin is fed into the cavity to perform resin molding.
Of the plunger that receives the resin tablet in the pot
On the pressure end face, the fitting recess provided on the end face of the resin tablet
A molding device with a centering mechanism for a resin tablet, characterized in that a projection is provided which fits into the molding device. 5. A resin tablet is supplied to a pot, and
Pressing and melting a resin tablet with a plunger
Molding equipment where the resin is pressure-fed to form the resin
In addition , a spherical resin tablet is provided on the pressing end face of the plunger.
A hemispherical recess for receiving
A molding device with a centering mechanism for a resin tablet.