JP2009034851A - Resin molding method and die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently prevent a clearance formed between a cavity bottom face member and a fittingly mounting part of a cavity holder member in a cavity block of a resin molding die (both upper and lower molds). <P>SOLUTION: This resin molding method comprises forming the cavity bottom face member 12 and the cavity holder member 13 of die materials with different thermal expansion coefficients, e.g., forming the cavity bottom face member 12 of a ceramic material and the cavity holder member 13 of an iron-based metallic material, and providing the cavity bottom face member 12 with an inclined face of a required angle θ. When a die temperature is raised by heating to a required molding temperature (e.g., 180°C) from a room temperature (e.g., 20°C), the cavity bottom face member 12 falls and slides by its own weight due to the difference of the thermal expansion coefficients. The cavity bottom face member 12 can thereby be fittingly mounted into the fittingly mounting part 14 of the cavity holder member 13 efficiently in terms of shape. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin molding method for molding a molded product with a resin material in a mold cavity for resin molding and an improvement of the mold.

  Conventionally, for example, using a resin molding die (resin sealing molding die for electronic parts), a resin molded body (molded product) corresponding to the shape of the mold cavity in the mold cavity with a resin material. ) Is performed, and this method is performed as follows.

For example, by using a transfer molding method, an electronic component (molded product) such as an IC mounted on a substrate (or a lead frame) is sealed with a resin material, and a resin molded body corresponding to the shape of a mold cavity (Molded product) is molded.
That is, by using a resin molding die (resin sealing molding die for electronic parts), first, the mold (both upper and lower molds) is heated to a molding temperature (for example, 180 ° C.), and the upper mold The board with the electronic components mounted on the board set part is set with the electronic parts facing downward, and the mold is clamped to place the electronic parts in the lower mold cavity. In addition, the resin material heated and melted in the pot is pressurized with a plunger to inject and fill the resin material (molten resin) heat-melted into the lower mold cavity.
Therefore, an electronic component is resin-sealed and molded in a resin molded body (molded product) corresponding to the shape of the cavity in the lower mold cavity.
After the curing time necessary for curing elapses, the mold (both upper and lower molds) is opened to release the resin molded body from the lower mold cavity.

Japanese Patent Laying-Open No. 2003-236843 [see FIG. 1 (1)]

By the way, the lower mold is provided with a cavity block having a cavity, and the cavity block is composed of a cavity bottom member and a cavity holder member for detachably fitting the cavity bottom member.
Accordingly, the cavity block is assembled by fitting the cavity bottom member to the fitting portion of the cavity holder member at room temperature.

However, since the mold materials forming the cavity bottom member and the cavity holder member are different, when the mold (both upper and lower molds) is heated to a molding temperature (for example, 180 ° C.), two mold materials Due to the difference in thermal expansion coefficient, a gap is likely to be generated between the cavity bottom member and the cavity holder member fitting portion.
For example, in the example illustrated in FIGS. 4A and 4B, the cavity bottom member 61 is formed of a ceramic material, and the cavity holder member 62 is formed of an iron-based metal material.
4 (1) and 4 (2), there is a cavity block 63 including a cavity bottom member 61 and a cavity holder member 62 having a fitting portion 64 on which the cavity bottom member 62 is detachably fitted. It is shown in the figure.
That is, as shown in FIG. 4 (1), in the cavity block 63 assembled at room temperature, no gap is formed between the cavity bottom surface member 61 and the fitting portion 64 of the cavity holder member 62.
However, as shown in FIG. 4 (2), when the cavity block 63 is heated to a molding temperature (for example, 180 ° C.), the bottom surface of the cavity where the coefficient of thermal expansion of the cavity holder member 62 is fitted to the fitting portion. Since the coefficient of thermal expansion of the member 61 is larger, a gap 65 is formed between the cavity bottom surface member 61 and the fitting portion 64 of the cavity holder member 62 due to the difference between the thermal expansion coefficients of both 61 and 62. The molten resin entered the gap 65 and hardened, causing the following adverse effects.
That is, when a resin material heated and melted is injected into the mold cavity and a molded product is molded in the mold cavity, the molten resin penetrates into the gap 65 and cures. There is an adverse effect that appearance defects (quality defects) occur in the molded product by being transferred to the molded product.
Further, since the molten resin penetrates into the gap 65 and is cured, the resin cured in the gap 65 is separated from the molded product and becomes a resin flash 66 and remains on the mold cavity surface 67.

Accordingly, an object of the present invention is to efficiently prevent a gap generated between a cavity bottom surface member and a fitting portion of a cavity holder member during resin molding.
In addition, the present invention can efficiently prevent a gap generated between the cavity bottom member and the fitting portion of the cavity holder member, effectively preventing a quality defect of the molded product and remaining on the mold cavity surface. It aims at preventing the resin flash which adheres efficiently.

  The resin molding method according to the present invention for solving the technical problem described above uses a resin molding die to heat the above-described die to a required temperature and to provide a resin provided in the above-described die. A resin molding method in which a molded product is resin-molded in a mold cavity for molding, wherein a cavity block having the above-described mold cavity is fitted with a cavity bottom member having a required inclined surface and the above-described cavity bottom member. A step of forming a cavity holder member having a fitting portion, a step of forming the cavity bottom member and the cavity holder member with mold materials having different thermal expansion coefficients, and a fitting portion of the cavity holder member. A step of fitting the above-mentioned cavity bottom member into the above-described mold cavity side in a state protruding at a predetermined distance, and the above-mentioned mold to a required temperature. The above-mentioned cavity bottom member is opposite to the above-mentioned mold cavity side due to the difference in thermal expansion coefficient between the above-mentioned cavity bottom member and the cavity holder member when the above-mentioned mold is heated. And the above-mentioned cavity bottom member is fitted to the above-mentioned cavity bottom member fitting portion by eliminating the gap between the above-mentioned cavity bottom surface member and the cavity holder member fitting portion when the above-mentioned cavity bottom surface slides. And a step of fitting to.

  In addition, a resin molding die according to the present invention for solving the above technical problem is a cavity formed from a cavity bottom member and a cavity holder member having a fitting portion for fitting the cavity bottom member. A resin molding die having a block and at least a heating means for heating the above-described mold cavity block, wherein the above-described cavity bottom member is provided with a required inclined surface, and the above-described cavity bottom member and cavity holder member Are formed of mold materials having different thermal expansion coefficients.

  In addition, the resin molding die according to the present invention for solving the technical problem described above is formed by forming the cavity bottom member from a ceramic material and using a metal as the cavity holder member for fitting the cavity bottom member. It is made of a material.

According to the present invention, there is an excellent effect that it is possible to efficiently prevent a gap generated between the cavity bottom surface member and the cavity holder member fitting portion during resin molding.
In addition, according to the present invention, it is possible to efficiently prevent a gap generated between the cavity bottom surface member and the cavity holder member fitting portion, thereby efficiently preventing a quality defect of the molded product and at the same time on the mold cavity surface. There is an excellent effect that it is possible to efficiently prevent the remaining resin burrs.

Embodiments according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 shows a resin molding die (resin sealing molding die for electronic parts) according to the present invention.
FIG. 2 (1) and FIG. 2 (2) are cavity blocks provided in the mold shown in FIG.
FIG. 3 (1) and FIG. 3 (2) are explanatory views for explaining a mold (cavity block) according to the present invention.

(Regarding the structure of the resin mold)
That is, as shown in FIG. 1, a resin molding die (resin sealing molding die for electronic parts) 1 according to the present invention is composed of a fixed upper die 2 and a movable lower die 3 disposed opposite to the upper die 2. And the upper and lower molds 2 and 3 are each provided with a heating means 4 separately.
Further, a substrate supply unit for supplying and setting a substrate 6 (or a lead frame) on which an electronic component (molded product) 5 such as an IC is mounted on the mold surface of the upper die 2 with the electronic component 5 facing downward. 7 is provided, and a lower mold cavity 8 for resin molding is provided on the mold surface of the lower mold 3.
In addition, the lower mold 3 includes a cavity block 9 having a lower mold cavity 8 and a lower mold base 10 on which the cavity block 9 is detachably fitted, and the cavity block 9 includes a cavity bottom surface 11. And a cavity holder member 13 for fitting the cavity bottom member 12 is provided.
The resin molding cavity 8 can be formed by the cavity bottom surface 11 of the cavity bottom surface member 12 and the cavity side surface 20 of the cavity holder member 13 at the time of resin molding by the mold 1 (2 · 3). ing.
Although not shown, the mold 1 is connected to a resin material supply pot for supplying a resin material, a resin pressurizing plunger fitted in the pot, and a pot and a cavity. Resin passages (cals, runners, gates, etc.) are provided.

Therefore, the upper and lower molds 2 and 3 are first heated by the heating means 4 to raise the upper and lower molds 2 and 3 from room temperature to a required molding temperature (for example, 180 ° C.), and then The substrate 6 having the electronic component 5 mounted on the substrate supply portion 7 of the mold 2 is set by supplying and setting the electronic component 5 with the electronic component 5 facing downward, and the upper and lower molds 2 and 3 are clamped to form the lower mold cavity 8. The electronic component 5 is fitted and set inside.
Next, the resin material (molten resin) heated and melted in the pot is pressurized with a plunger to be injected and filled into the lower mold cavity 8 through the resin passage.
After the time required for curing has elapsed, both the upper and lower molds 2 and 3 are opened so that an electronic component is formed in the resin molded body (molded product) 21 corresponding to the shape of the lower mold cavity 8 in the lower mold cavity 8. It is comprised so that 5 can be sealingly molded.

(Cavity bottom member)
As described above, the cavity block 9 includes the cavity bottom member 12 and the cavity holder member 13, and the cavity block 9 (cavity bottom member 12 and The cavity holder member 13) can be heated from room temperature (for example, 20 ° C.) to a required molding temperature (for example, 180 ° C.).
Further, as shown in FIGS. 2A and 2B, at a required position of the cavity holder member 13, a fitting portion 14 (a recess or a through hole) for detachably fitting the cavity bottom surface member 12 is provided. The cavity bottom member 12 can be detachably fitted to the fitting portion 14 while being provided.
The cavity bottom member 12 (outside sidewall surface) is provided with an inclined surface 15 having a required angle θ with respect to the cavity bottom surface 11, and the cavity holder member 13 has a fitting portion 14 (inside of the fitting portion 14). On the side wall surface, an inclined surface 16 having a required angle corresponding to the inclined surface 15 is formed.
That is, in the cavity block 9 of the lower mold 3, the inclined surface 15 of the cavity bottom surface member 12 is expanded in a direction from the inner lower side of the fitting portion 14 toward the cavity bottom surface 11, and is in a so-called forward tapered shape. It is provided and configured.
Therefore, for example, the required angle θ between the cavity bottom surface 11 and the side surface of the cavity bottom surface member 12 is an acute angle.
For example, when the shape of the cavity bottom surface 11 (the shape on the cavity bottom surface side of the cavity bottom surface member 12) is a square shape, the cavity bottom surface member 12 itself is formed in the shape of a quadrangular pyramid.

(About mold materials with different thermal expansion coefficients)
The cavity bottom member 12 and the cavity holder member 13 constituting the cavity block 9 are formed of mold materials having different thermal expansion coefficients, and the thermal expansion coefficient of the mold material forming the cavity holder member 13 is Typically, the coefficient of thermal expansion of the mold material forming the bottom member 12 is greater.
That is, the cavity holder member 13 is formed of an iron-based metal material, and the cavity bottom member 12 is formed of a ceramic material.
For example, SKD11 (thermal expansion coefficient: 11.2 × 10 ⁻⁶ / ° C.) can be cited as an iron-based metal material, and alumina ceramics (thermal expansion coefficient: 7 × 10 ⁻⁶ / ° C.), zirconia can be cited as ceramic materials. Ceramics (thermal expansion coefficient: 9.5 × 10 ⁻⁶ / ° C.) can be mentioned.
The measurement of the thermal expansion coefficient is based on JIS standard R1618.
Therefore, when the cavity block 9 is heated from room temperature to the molding temperature by the heating means 4, the thermal expansion of the cavity holder member 13 is larger than the thermal expansion of the cavity bottom member 12, so that the heat of the cavity bottom member 12 is increased. The space part of the fitting part 14 will expand greatly from expansion | swelling.

(Fitting of cavity bottom member)
Next, the operation of the cavity bottom member 12 will be described with reference to FIGS. 2 (1), 2 (2), 3 (1), and 3 (2).
3 (1) and FIG. 3 (2) are simplified illustrations of FIG. 2 (1) and FIG. 2 (2) in order to explain the principle of the present invention. 3A is a diagram corresponding to FIG. 2A, and FIG. 3B is a diagram corresponding to FIG.

2 (1) [FIG. 3 (1)] is a mold (cavity block 9) at room temperature (for example, 20 ° C.), and FIG. 2 (2) [FIG. 3 (2)] is a molding. This is a mold (cavity block 9) in a temperature (for example, 180 ° C.) state.
That is, as shown in FIG. 2 (1), in the cavity block 9 set to room temperature, the position of the cavity bottom surface 11 of the cavity bottom surface member 12 is “required position 17 during resin molding” shown in FIG. ”At a required height 18 (with a small distance 18 from the original required position 17).
At this time, a gap (clearance) 19 is formed between the cavity bottom surface member 12 and the fitting portion 14 of the cavity holder member 13.
Further, as shown in FIG. 2 (2), in the cavity block 9 set to the molding temperature, the cavity bottom member 12 is fitted to the fitting portion 14 of the cavity holder member 13 with no gap. ing.
At this time, the position of the cavity bottom surface 11 in the cavity bottom surface member 12 is “a required position 17 during resin molding”.
At this time, the cavity bottom surface member 12 and the cavity holder are configured so that the cavity bottom surface member 12 can be efficiently and geometrically fitted to the fitting portion 14 of the cavity holder member 13 (accurately fit). It is comprised so that a clearance gap may not be formed between the fitting parts 14 of the member 13 (a clearance gap may be eliminated).
Therefore, as shown in FIG. 2 (2), the cavity bottom surface 11 of the cavity bottom surface member 12 and the cavity side surface 20 of the cavity holder member 13 can be configured to form a resin molding cavity 8 having a required shape. Yes.

That is, when the cavity block 9 (cavity bottom member 12 and cavity holder member 13) in the room temperature state shown in FIG. Larger thermal expansion.
For this reason, as shown in FIG. 2 (2), the cavity bottom member 12 slides (becomes slid) downward due to its own weight, so that the cavity bottom member 12 is attached to the fitting portion 14. It is configured so that it can be fitted efficiently in terms of shape.
Therefore, the bottom surface member 12 of the cavity is configured in a state where the bottom surface 11 protrudes into the cavity 8 at a required height (distance) 18 at room temperature. Since the bottom surface member 12 is efficiently fitted into the fitting portion 14 of the cavity holder member 13, the cavity bottom surface 11 of the cavity bottom surface member 12 and the cavity side surface 20 of the cavity holder member 13 have a required shape for resin molding. 8 can be configured.
At this time, it is possible to efficiently prevent a gap from being formed between the cavity bottom surface member 12 and the fitting portion 14 of the cavity holder member 13 by sliding the cavity bottom surface member 12 by its own weight.
Further, in this state (with no gap between the cavity bottom member 12 and the fitting portion 14 of the cavity holder member 13), the resin is molded in the lower mold cavity 8 to be molded in the cavity 8. It is possible to efficiently prevent the quality of the resin molded body (molded product) 21 (deteriorated appearance) and the occurrence of resin flash remaining on the mold cavity bottom surface 11.
When the cavity block 9 is cooled from the molding temperature state shown in FIG. 2B to the room temperature state, the bottom surface 11 of the cavity bottom surface member 12 is formed into the cavity 8 by the cooling contraction force by the side wall surface of the fitting portion 14. It protrudes to the side at a required height (distance) 18.

Therefore, according to the present invention, it is possible to efficiently prevent a gap generated between the cavity bottom surface member 12 and the fitting portion 14 of the cavity holder member 13 during resin molding.
In addition, according to the present invention, it is possible to efficiently prevent a gap generated between the cavity bottom surface member 12 and the fitting portion 14 of the cavity holder member 13, and efficiently prevent a quality defect of the molded product 21, Resin flash remaining on the surface of the mold cavity 8 can be efficiently prevented.

  The present invention is not limited to the above-described embodiments, and can be arbitrarily changed and selected as needed within a range not departing from the gist of the present invention.

In the above-described embodiments, the cavity bottom member 12 formed of a ceramic material and the cavity holder member 13 formed of a metal material have been described. However, the present invention is applicable to other materials having different thermal expansion coefficients. The resin molding die 1 according to the above can be formed.
The above-described embodiment shows a case where the thermal expansion coefficient of the mold material forming the cavity holder member 13 is made larger than the thermal expansion coefficient of the mold material forming the cavity bottom member 12.

  In the above-described embodiment, the resin molding die (resin sealing molding die for electronic parts) has been described as an example. However, for example, the present invention can also be applied to an injection molding die and a compression molding die. Is something that can be done.

Further, according to the present invention, the cavity block 9 in the above-described mold is composed of a cavity holder member 13 made of an iron-based metal material and a cavity bottom member 12 made of a ceramic material, and the cavity bottom member 12 made of a ceramic material. It can be configured to have a large number of fine communication holes.
In this case, compressed air can be pumped into the cavity 8 through a large number of fine communication holes, or air can be forcibly sucked and discharged from the cavity 8.
For example, the resin molded body 21 can be protruded and released from the cavity 8 by pumping compressed air through a large number of fine communication holes to the resin molded body 21 molded in the cavity 8. ing.
In addition, for example, the release film can be covered along the shape of the cavity 8 by forcibly sucking and discharging air from the cavity 8.

FIG. 1 is a schematic longitudinal cross-sectional view schematically showing a resin molding die (resin sealing molding die for electronic parts) according to the present invention, and shows a fitted state of a cavity bottom member at room temperature. ing. 2 (1) and 2 (2) are enlarged schematic longitudinal sectional views schematically showing an enlarged main part (cavity block) of the mold shown in FIG. 1, and FIG. 2 (1) is a diagram. 1 shows a fitting state of the cavity bottom member at room temperature, and FIG. 2B shows a fitting state of the cavity bottom member at the molding temperature. 3 (1) and 3 (2) are explanatory views (schematic longitudinal sectional views) for explaining the principle according to the present invention. FIG. 3 (1) corresponds to FIG. 2 (1), and FIG. (2) corresponds to FIG. 2 (2). 4 (1) and 4 (2) are explanatory views (schematic longitudinal sectional views) for explaining a conventional example. FIG. 4 (1) corresponds to FIG. 3 (1), and FIG. Corresponds to FIG. 3 (2).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold for resin molding 2 Fixed upper mold | type 3 Movable lower mold | type 4 Heating means 5 Electronic component 6 Board | substrate 7 Board | substrate supply part 8 Lower mold cavity 9 Cavity block 10 Lower mold base 11 Cavity bottom face 12 Cavity bottom face member 13 Cavity holder member 14 Fit Mounting part 15 Inclined surface of cavity bottom member 16 Inclined surface of fitting part 17 Cavity bottom surface position during resin molding 18 Height (distance)
19 Clearance 20 Cavity Side 21 Resin Molded Body θ Angle

Claims (3)

This is a resin molding method in which the above-mentioned mold is heated to a required temperature using a resin molding mold, and the molded product is resin-molded in a mold cavity for resin molding provided in the above-mentioned mold. And
Forming a cavity block having the above-described mold cavity from a cavity bottom member having a required inclined surface and a cavity holder member having a fitting portion for fitting the cavity bottom member;
Forming the cavity bottom member and the cavity holder member with mold materials having different thermal expansion coefficients;
A step of fitting the cavity bottom member described above into the fitting portion of the cavity holder member described above in a state of protruding at a predetermined distance on the mold cavity side;
Heating the aforementioned mold to a required temperature;
A step of sliding the cavity bottom member in a direction opposite to the mold cavity side due to a difference in thermal expansion coefficient between the cavity bottom member and the cavity holder member when the mold is heated. When,
A step of fitting the above-described cavity bottom member into the above-described fitting portion of the above-mentioned cavity holder member by eliminating the gap between the above-described cavity bottom-surface member and the fitting portion of the cavity holder member when the above-described cavity bottom surface slides. The resin molding method characterized by the above-mentioned.   A mold for resin molding comprising a cavity block formed from a cavity bottom member and a cavity holder member having a fitting portion for fitting the above-described cavity bottom member, and at least a heating means for heating the above-described mold cavity block The above-described cavity bottom member is provided with a required inclined surface, and the cavity bottom member and the cavity holder member are formed of mold materials having different thermal expansion coefficients. Type.   5. The mold for resin molding according to claim 4, wherein the cavity bottom member is formed of a ceramic material, and the cavity holder member into which the cavity bottom member is fitted is formed of a metal material.

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