JP4568258B2 - Mold and molding method - Google Patents

Description

  The present invention relates to a mold, and more particularly to a mold having a movable cavity structure.

  Conventionally, a resin sealing device 1 shown in FIG. 4 is known (see Patent Document 1).

  The resin sealing device 1 is a device that seals the molded product 20 with resin in a cavity 30 formed by combining the upper mold 2 and the lower mold 3.

  The upper mold 2 of the resin sealing device 1 is configured to include an upper mold body composed of an upper mold chase block 5 and an upper mold frame block 6 and an upper mold cavity block 4. Further, the upper die cavity block 4 is arranged so as to be movable (vertical movement in FIG. 4) with respect to the upper die chase block by a disc spring 7, and has a so-called “movable cavity structure”. Such a movable cavity structure appropriately absorbs a thickness error (overall and partial thickness errors) of the molded product 20, and an excessive clamping pressure is applied to the molded product 20, or the clamping pressure is increased. Used to prevent resin leakage due to shortage.

Japanese Patent Laid-Open No. 11-16932

  When the movable cavity structure as described above is configured, a slight gap G is formed between the two so that the upper mold cavity block 4 can move relative to the upper mold block 6. . However, the presence of the gap G may cause the upper mold cavity block 4 to tilt during the molding operation. That is, when sealing resin or the like enters the gap G by repeated sealing operations, the sliding state with respect to the upper mold block 6 of the upper mold cavity block 4 deteriorates, and the upper mold cavity block 4 is inclined. End up. Referring to FIG. 5, the upper mold cavity block 4 remains along the line (the upper mold cavity block 4 is along the line B-B with respect to the molded product 20 arranged along the line AA. When the mold is clamped, a high clamping pressure is applied only to a part of the molded product 20 (arrow indicated HP section). On the other hand, the clamping pressure is not sufficiently applied to other portions. As a result, there is a bias in the clamp balance with respect to the molded product 20 during mold clamping, causing damage to the molded product 20 or resin leakage. This makes it impossible to take advantage of the movable cavity structure.

  Therefore, an object of the present invention is to provide a mold that can be clamped after correcting the inclination of the movable cavity block at the time of mold clamping while adopting the movable cavity structure.

The present invention provides a mold having a movable cavity structure in which a cavity formed by combining a first mold and a second mold, wherein the movable cavity block constituting the movable cavity structure is the first mold. The movable body block is movably disposed through an elastic body, and at least one of the second mold side surface of the movable cavity block and the movable cavity block side surface of the second mold is contacted with the mating surface. A protrusion for correcting the inclination of the movable cavity block by contact, and the height of the protrusion of the protrusion when the movable cavity block is clamped with the movable cavity block tilted. The protrusion can be brought into contact with the mating surface and tilted before it comes into contact with the workpiece placed in the cavity. When it is clamping the stomach condition is to solve the above problems by setting the height of the protrusion does not abut against the mating surface.

By adopting such a configuration, even when the movable cavity block is tilted, it is possible to perform mold clamping after correcting the tilt. As a result, the clamp balance for the molded product is equalized. Further, it is possible to sufficiently exhibit the “movable” effect of the movable cavity block that is movably disposed via the elastic body. And reliable tilt correction can be realized without obstructing normal clamping.

  In addition, the “tilt correction mechanism” can be realized with a simple configuration such as a protrusion, and the overall cost of the apparatus can be prevented from being increased due to the provision of the mechanism. Moreover, since the mechanism itself is simple, the reliability of the mechanism can be maintained high over a long period of time.

  Further, if a plurality of the protrusions are arranged as a pair, it becomes possible to cope with the inclination of the movable cavity block in various directions.

  In addition, if the protrusion is configured to be replaceable as an independent part, it can be flexibly adapted to the type of the molding target to be sealed.

The present invention also relates to a molding method using a mold in which a cavity formed by combining the first mold and the second mold has a movable cavity structure, and a movable cavity block constituting the movable cavity structure. When the mold is clamped in a tilted state, the second cavity side surface and the second mold side of the movable cavity block before the movable cavity block comes into contact with the molded product arranged in the cavity. As a molding method characterized in that a protrusion provided on at least one of the movable cavity block side surface of the mold is brought into contact with the mating surface, thereby correcting the inclination of the movable cavity block and then clamping the mold. It is also possible to capture.

  By applying the present invention, the function of the movable cavity structure can be sufficiently exerted, and damage to the molded product and resin leakage can be prevented.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a side sectional view of a mold 100 that is an example of an embodiment of the present invention. FIG. 2 is an enlarged view around the protrusion (tilt correction mechanism) in FIG.

  The mold 100 is composed of an upper mold (first mold) 110 and a lower mold (second mold) 130. The mold 100 has a die set, a press mechanism, and the like (not shown), and the upper mold 110 and the lower mold 130 can be brought into contact with and separated from each other at a predetermined timing. Has been.

  The lower mold 130 includes a lower mold cavity block 135 on which a molded product 150 conveyed by a conveyance mechanism (not shown) is placed, a lower mold block 133 disposed around the lower mold cavity block 135, The lower mold cavity block 135 and the lower mold chase block 132 are arranged below the lower mold block 133 (lower side in FIG. 1). The lower mold cavity block 135, the lower mold frame block 133, and the lower mold chase block 132 are integrated as a whole.

  On the other hand, the upper mold 110 includes an upper mold cavity block (movable cavity block) 115 constituting the cavity 140, an upper mold second frame block 114 disposed around the upper mold cavity block 115, and the upper mold first. A configuration having an upper mold first frame block 113 disposed further outside the two-frame block 114 and an upper mold chase block 112 disposed above each block 113, 114, 115 (upper side in FIG. 1); Has been. The upper mold chase block 112, the upper mold first frame block 113, and the upper mold second frame block 114 constitute an upper mold main body 110A.

  The upper mold cavity block 115 is movably disposed with respect to the upper chase block 112 via a disc spring (elastic body) 117, and is configured by adopting a so-called “movable cavity structure”.

  Here, the movable cavity structure will be described. The upper chase block 112 is provided with a plurality of pin holes 113A. A pin 119 is inserted into each of the pin holes 113A. The head 119A of the pin 119 is set to have a larger diameter than the diameter of the pin hole 113A, and the pin 119 is prevented from falling off. On the other hand, the tip end side (lower side in FIG. 1) of the pin 119 is connected to the upper surface (upper surface in FIG. 1) of the upper mold cavity block 115, and the pin 119 and the upper mold cavity block 115 are integrated. . In other words, the upper mold cavity block 115 is suspended by the pins 119. Further, when the pin 119 is in the lowest position (that is, the head 119A of the pin 119 is in contact with the upper die chase block 112), the lower surface of the upper die chase block 112 and the upper die cavity block The length of the pin 119 is set so that a predetermined gap G3 is generated between the upper surface of 115. A presser block 116 is disposed between the upper die chase block 112 and the upper die cavity block 115. The presser block 116 is provided with a disc spring storage hole 116A at a position corresponding to the pin hole 113A described above. A disc spring (elastic body) 117 is disposed in the disc spring storage hole 116 </ b> A, and a pin 119 passes through the center of the disc spring 117. That is, the disc cavity 117 constantly biases the so-called suspended upper mold cavity block 115 downward (lower side in FIG. 1). With such a structure, when a large pressure is applied to the upper mold cavity block 115 from the lower mold 130 side during mold clamping, the disc spring 117 is compressed, so that the upper mold cavity block 115 is It will move to the upper chase block 112 side. The upper mold cavity block 115 can be moved until the upper mold cavity block 115 comes into contact with the surface of the presser block 116 at the maximum. In the present embodiment, the disc spring 117 is employed as the elastic body, but the present invention is not limited to this, and a coil spring, rubber, and the like can also be widely used.

  Further, on the surface of the upper mold cavity block 115 (the surface on the lower mold 130 side), a protrusion 118 is provided as an “inclination correction mechanism”. In the present embodiment, the protruding portion 118 is made of the same member as the members constituting the upper mold 110 and the lower mold 130 (hereinafter referred to as mold constituent members), but slightly more than the mold constituent members. If it is made of a member having a small elastic coefficient, it is possible to reduce the impact caused by the contact. Further, the protrusions 118 are formed as a pair, and are on a straight line on the surface passing through the center O (see FIG. 3) of the surface of the movable mold block 115 on the lower mold 130 side, and from the center O. Arranged at equidistant positions. In FIG. 3, a total of four protrusions 118 are arranged, and it is possible to cope with the inclination of the upper mold cavity block 115 in various directions. The function of “correcting” can be exhibited. In addition, the function of “correcting the inclination” itself is not necessary even if the pair of protrusions are not necessarily arranged on the straight line passing through the center O (for example, even if arranged at a position deviated from the linear shape). obtain.

  Further, the protrusion height H of the protrusion 118 is such that when the mold is clamped with the cavity block 115 tilted, the protrusion 118 has a lower mold before the upper mold cavity block 115 abuts the product 150. It is possible to abut the surface of the lower mold 130 so that the projection 118 does not abut the surface of the lower mold 130 (details will be described later). Is set. In this embodiment, since the mounting surface P1 of the molded product 150 in the lower mold cavity block 135 and the contact surface P2 of the projection 118 are on the same plane, the projection height H is determined by the molded product. The thickness is set to 150 or less (see FIG. 2). Of course, even if the placement surface P1 of the molded product 150 and the contact surface P2 of the projection 118 in the lower mold cavity block 135 are not on the same plane, it is sufficient to design accordingly.

  The position of the protrusion 118 may be any position as long as the inclination of the movable cavity block (the upper mold cavity block 115 in the present embodiment) can be corrected, but the following positions are more effective.

  If the shape of the entire product to be molded (for example, the shape of a lead frame including a plurality of semiconductor chips) is not square and there are a longitudinal direction and a short direction, the protrusion 118 is formed along the longitudinal direction. It is desirable to arrange. This is because as the distance between the protrusions 118 forming the pair increases, the inclination can be forced with a smaller reaction force (reaction force received when the protrusion 118 abuts against the lower mold 130). .

Further, in order to allow the upper mold cavity block 115 to slide (up and down) with respect to the upper mold second frame block 114, there is a slight gap between the upper mold cavity block 115 and the upper mold second frame block 114. Is formed. Therefore, when the thickness of the upper mold cavity block 115 is L1 and the gap amount is G1, the maximum inclination angle θ of the upper mold cavity block 115 is
θ = arctan (G1 / L1) (1)
It becomes.

  In the present embodiment, the protrusion height H should not be set to be equal to or greater than the thickness D of the molded product (see FIG. 2). This is because it is difficult to clamp normally if the projection height H is equal to or greater than the thickness D of the molded product.

Accordingly, the projection height H is set to the same height as the thickness D of the molded product, and a margin gap G2 is set between the upper cavity block 115 and the molded product 150 in a tilted state as a safety margin. In this case, the distance L2 (see FIG. 2) between the end of the molded product 150 and the end of the protrusion 118 is
L2 ≧ G2 / sin θ (2)
Set to. Actually, as described above, since the projection height H is set lower than the thickness D of the molded product, the following equation is further derived.

  L2 ≧ {G2 + (HD)} / sin θ (3)

  By setting the arrangement and the height of the protrusions 118 under such conditions, it is possible to expect a reliable operation of the inclination correction mechanism.

  Further, the protrusion 118 is fixed as an independent part so as to be replaceable. For example, the upper mold cavity block 115 may be simply fitted into the upper mold cavity block 115, or may be replaceable by screwing. With such a configuration, it is possible to adjust the height of the projecting portion according to the type of the molded product using, for example, shims and spacers.

  Next, the operation of the mold 100 will be described.

  When the molded product 150 is transported to the surface of the lower mold 130 by a transport mechanism (not shown), the upper mold 110 and the lower mold 130 start to be closed by a press mechanism (not shown). At this time, since the protrusion height H and position of the protrusion 118 are set to the height and position described above, if the upper mold cavity block 115 is inclined, the upper mold cavity is clamped by clamping. Before the block 115 comes into contact with the molded product 150, the protrusion 118 comes into contact with the lower mold 130 (the surface of the lower mold cavity block 135). By this contact, the inclination of the upper mold cavity block 115 is corrected, and thereafter, the mold clamping is performed. As a result, the clamping pressure does not partially concentrate on the molded product 150, and the molded product 150 can be prevented from being damaged. At the same time, there is no partial pressure shortage in the molded product 150, and leakage of the sealing resin to be introduced can be prevented. In other words, the presence of the protrusion 118, which is an inclination correction mechanism, allows the “movable cavity structure” to function sufficiently, and the function of the movable cavity structure (the function of absorbing the thickness error of the molded product) is sufficient. It is possible to make it appear.

  On the other hand, when the upper mold cavity block 115 is not inclined, the projection does not hinder the clamping even when the mold is clamped, and normal clamping can be realized.

  In the embodiment shown in FIGS. 1 to 3, the so-called “movable cavity” is provided on the upper mold 110 side. However, the present invention is not limited to this, and the lower mold 130 side (that is, the side) The upper and lower molds may be reversed).

  In the above-described embodiment, all the protrusions are provided on the so-called “movable cavity” side. However, the present invention is not limited to this. (2 molds) side may be provided.

  The present invention can be widely applied not only to a transfer type resin sealing device but also to a compression molding type resin sealing device.

Side sectional view of a mold as an example of an embodiment of the present invention Enlarged view around arrow II in Fig. 1 View of the upper mold cavity block (movable cavity block) from the lower mold side Sectional drawing of the resin sealing device disclosed in Patent Document 1 Enlarged view around arrow V in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Mold die 110 ... Upper die 112 ... Upper die chase block 113 ... Upper die first frame block 114 ... Upper die second frame block 115 ... Upper die cavity block (movable cavity block)
DESCRIPTION OF SYMBOLS 116 ... Presser block 116A ... Disc spring storing hole 117 ... Disc spring 118 ... Protruding part 119 ... Pin 130 ... Lower mold 132 ... Lower mold chase block 133 ... Lower mold block 135 ... Lower mold cavity block 150 ... Molded article

Claims (5)

A mold mold in which a cavity formed by combining the first mold and the second mold has a movable cavity structure,
A movable cavity block constituting the movable cavity structure is movably disposed from the main body of the first mold via an elastic body; and
A protrusion for correcting the inclination of the movable cavity block by contacting at least one of the second mold side surface of the movable cavity block and the movable cavity block side surface of the second mold by contacting the other side surface. Part is provided ,
When the movable cavity block is clamped with the movable cavity block tilted, the protrusion height of the protrusion is determined so that the protrusion is in contact with the molded product placed in the cavity before the movable cavity block comes into contact with the molded product. A mold metal that is capable of abutting against the mating surface and is set to a height that prevents the projection from abutting against the mating surface when the mold is clamped without tilting. Type. In claim 1,
The mold is characterized in that the projections are arranged in pairs on the surface of the movable cavity block on the second mold side. In claim 2,
A plurality of the protrusions are arranged in a mold. In any one of Claims 1 thru | or 3 ,
The mold is characterized in that the protrusion is configured to be replaceable as an independent part. A mold method using a mold in which a cavity formed by combining a first mold and a second mold has a movable cavity structure,
When the movable cavity block constituting the movable cavity structure is clamped in a tilted state, the movable cavity block before the movable cavity block comes into contact with a workpiece placed in the cavity, 2 After the protrusions provided on at least one of the mold side surface and the movable cavity block side surface of the second mold are in contact with the mating surface, the inclination of the movable cavity block is corrected, A molding method characterized by tightening.

Images