JP3208758B2 - Injection compression molding method and injection compression molding die apparatus used in this method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection compression molding method used for molding, for example, a thermoplastic resin, and a mold apparatus for injection compression molding used in this method.

[0002]

FIG. 5 shows a main body of an IC card P which is an example of a thin product formed of resin. The IC card P has a substantially rectangular flat shape with a thickness of about 1.2 mm, and has one surface flat and the other surface formed with a recessed IC chip mounting portion P1. ing. A recess P2 is further formed at the center of the IC chip mounting portion P1. Therefore, in the IC card P, the IC chip mounting portion P1 has a thinner portion than other portions, and the concave portion P2 has a thinner portion. The thickness of the IC card P in the recess P2 is about 0.16 mm.

[0003] In molding a thin product such as the IC card P, problems such as poor filling and poor precision are likely to occur, so that injection compression molding is sometimes used. In this injection compression molding, as shown by a solid line in FIG. 6, for example, a molten thermoplastic resin as a molding material is injected into a cavity 3 formed between a closed fixed mold 1 and a movable mold 2. After filling (filling step), as shown by the dashed line,
And the movable mold 2 are further closed to compress the resin in the cavity 3 to be the IC card P (compression step). The cavity 3 having a larger volume than the final product shape in this way
Filling the inside with resin prevents poor filling, and then compresses the resin in the cavity 3 to improve accuracy. In FIG. 6, 4
Is a nest for forming an IC chip mounting portion P1, and a protrusion 5 for forming a recess P2 is provided on the distal end surface of the nest 4.
Are formed. And in the conventional mold device,
The insert 4 was fixed to the movable mold 2.

When the molten thermoplastic resin is filled in the cavity 3, the surface layer of the resin in contact with the wall surface of the cavity 3 cools quickly and becomes hard, forming a so-called skin layer. However, since the portion of the IC card P having the concave portion P2 is very thin, the ratio of the skin layer to the total thickness becomes high, and the whole becomes hard before the compression step. Therefore, compression is hindered by the skin layer of the concave portion P2, and there is a problem that the molded IC card P becomes thicker than the standard.

The present invention is intended to solve such a problem. In injection compression molding of a product having a thin portion such as an IC card, a molding material filled in a portion corresponding to the thin portion is used. It is intended to prevent compression from being hindered.

[0006]

According to a first aspect of the present invention, there is provided a mold apparatus having a plurality of molds which are opened and closed with each other and form a product-shaped cavity therebetween when the mold is closed. And filling the cavity with a molding material, and then compressing the molding material in the cavity by reducing the volume of the cavity, wherein the first mold of the plurality of molds is A movable nest that moves toward and away from the other second mold body and forms a thin portion of the product is movably assembled to the body, and the movable nest is close to the second mold body and the cavity is closed. After filling the molding material into the cavity, the pressure of the resin in the cavity 13 is regulated to a constant value.
Is regulated and regulated, and then the second mold is applied to the first mold body.
The mold is finally closed and the excess resin in the cavity is
Return and measure the amount of resin remaining in the cavity.
Then, the movable insert is separated from the second mold body, and the resin in the cavity is compressed.

As a result, the portion corresponding to the thin portion of the product in the cavity is filled with the molding material later than the other portions, and the molding material in the portion corresponding to the thin portion is still soft while the resin in the cavity is still soft. Is compressed. Therefore, the compression is smoothly performed without being hindered by the molding material in the portion corresponding to the thin portion.

According to a second aspect of the present invention, there is provided an injection compression molding die apparatus used in the injection compression molding method according to the first aspect of the present invention, wherein a plurality of cavities having a product shape are formed therebetween when the mold is closed. And a movable insert that moves closer to and away from the other second mold to form a thin portion of the product is movably assembled to the first mold of the plurality of molds. When the movable insert is urged toward the second mold body by a spring and the spring biases the movable insert, when the molding material is filled in the cavity, the movable insert is used as the movable insert. The state close to the second body is maintained, and
When the molding material in the cavity is compressed, the movable insert is set to a size that is separated from the second mold by the pressure of the molding material , and the first mold of the second mold is removed.
The movable body can be moved to the mold side by a predetermined range in the mold opening and closing direction.
While supporting, the moving body is biased toward the first mold body.
It has been done.

Therefore, when the cavity is empty,
The movable insert is close to the second mold body due to the force of the spring, and in this state, the molding material is filled in the cavity. After that, the molding material in the cavity is compressed,
Accordingly, when the pressure of the molding material in the cavity increases, the movable insert inserts into the second position against the force of the spring due to the pressure.
The molding material is filled in the cavity corresponding to the thin portion of the product in the cavity.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. In this embodiment, high pressure injection molding (in-mold measurement compression molding), which is a kind of injection compression molding, is taken as an example, and the product to be molded is the above-described IC card P. In the drawings,
For clarity, the thickness of the IC card P is exaggerated.

First, the configuration of a mold apparatus for injection compression molding will be described. Reference numeral 11 denotes a fixed mold as the second mold, and 12 denotes a movable mold as the first mold.
Moves vertically in the figure to open and close each other, and when the mold is closed, a plurality of product-shaped cavities 13 are formed therebetween. The thickness direction of the product IC card P is fixed type.
The mold opening and closing directions of the movable mold 11 and the movable mold 12 are matched.

The fixed die 11 includes a fixed mounting plate 16 mounted on a fixed platen (not shown) of the injection molding machine, and a fixed mounting plate 16 fixed to a surface of the fixed mounting plate 16 on the movable mold 12 side. And a side receiving plate 17. A locate ring 18 and a sprue bush 19 are fixed to the fixed-side mounting plate 16. This sprue bush 19
Is connected to a nozzle 20 of a heating cylinder device, which is a material supply device provided in the injection molding machine, and has a sprue 21 as a material passage therein, and a fixed receiving plate 17.
And protrudes to the movable mold 12 side.

On the movable mold 12 side of the fixed-side receiving plate 17,
A moving plate 26 as a moving body is supported so as to be movable in a predetermined range in the mold opening and closing direction. A sleeve 30 fixed by bolts 29 together with a stopper 28 on the movable mold 12 side of the fixed-side receiving plate 17 slidably penetrates the movable plate 26. The stopper 28 comes into contact with the movable plate 26 from the movable die 12 side, so that the movable plate 26 and the fixed-side receiving plate 17 of the fixed die 11 are fixed.
And the maximum gap between them, that is, the maximum opening amount. The movable plate 26 is urged toward the movable mold 12 with respect to the fixed-side mounting plate 16 by a spring 31 sandwiched between the fixed-side mounting plate 16 and the moving plate 26 in a compressed state. The tip of the sprue bush 19 is
It is slidably fitted in a through hole 32 formed in 26.

Further, a cylindrical cavity insert 36 is fixed to the fixed mold 11 by being sandwiched between a fixed side mounting plate 16 and a fixed side receiving plate 17. The cavity insert 36 forming a projection penetrates through the fixed-side receiving plate 17 and protrudes toward the movable mold 12, and slidably penetrates a through-hole 37 formed in the movable plate 26.

The movable die 12 has a movable mounting plate (not shown) mounted on a movable platen of an injection molding machine, and a movable receiving plate fixed to a surface of the movable mounting plate on the fixed mold 11 side. Fixed type of plate 41 and movable side receiving plate 41
And a movable mold plate 42 fixed to the surface on the 11th side. The movable mold plate 42 abuts against the movable plate 26 on the fixed mold 11 side and closes.The movable mold plate 42 and the movable plate 26 are guided by the movable plate 26 to guide each other. The insert 43 is fixed, and the guide insert is
A through-hole 44 into which the 43 is slidably fitted is formed.
The movable mold plate 42 is formed with a concave portion 45 into which the cavity insert 36 of the fixed mold 11 is slidably and detachably fitted. The fitting surface between the cavity insert 36 and the concave portion 45 forms a columnar surface parallel to the mold opening and closing direction.
The cavity 13 having the final product shape is formed by the cavity insert 36 and the concave portion 45. That is, the leading end surface of the cavity insert 36 forms one surface of the IC card P, the bottom surface of the concave portion 45 forms the other surface of the IC card P, and the inner peripheral surface of the concave portion 45 faces the side surface of the IC card P. To form.

Further, between the closed moving plate 26 and the movable mold plate 42, a runner 46 which is a material passage leading to the sprue 21 and a gate from the runner 46 to the cavity 13 are provided.
47 are formed. This gate 47
The cavity insert 36 and the recess 45 are closed by fitting each other. The spring 31 is a moving plate
The urging force is set to a force that keeps the movable plate 26 and the movable mold 12 closed against the pressure of the resin R in the runner 46.

The movable mold 12 is provided with a movable insert 51 for forming an IC chip mounting portion P1 and a concave portion P2 of the IC card P so as to be movable within a predetermined range in the mold opening and closing direction. The movable insert 51 moves with respect to the movable-side receiving plate 41 and the movable-side mold plate 42 in a state where the fixed mold 11 and the movable mold 12 are closed, so that the cavity insert 36 of the fixed mold 11 is moved.
It opens and closes with respect to. In order to assemble the movable insert 51, a through-hole 52 is formed in the movable-side mold plate 42, and a surface of the movable-side receiving plate 41 closer to the movable-side mold plate 42 has an opening area larger than that of the through-hole 52. Is formed. The bottom surface of the concave portion 53 forms a stopper surface 54.
The movable insert 51 is slidably fitted in the through hole 52 of the movable mold plate 42, and a flange formed at an end of the movable receiving plate 41 of the movable insert 51. 55 is movable side receiving plate 41
Is slidably fitted in the concave portion 53 of the second member. The movable insert 51 has its flange 55 abutted against the movable mold plate 42 or the stopper surface 54 of the concave portion 53 so that the movable range is restricted. Along with this, the movable nest 51
It is constantly urged toward the fixed mold 11 by a spring 56 as a spring assembled in the movable side receiving plate 41. The force by which the spring 56 urges the movable insert 51 is maintained such that the movable insert 51 abuts against the cavity insert 36 during a filling process described later in detail, and the resin in the cavity 13 during the compression process. The movable insert 51 is set to be large enough to be separated from the cavity insert 36 by the pressure of (1). As described above, the movable insert 51 has a distal end projecting into the concave portion 45 of the movable mold plate 42, and the distal end surface of the movable insert 51 has a convex portion forming the concave portion P 2 of the IC card P. 57 are formed.

Next, an injection compression molding method using the mold apparatus will be described. A mold clamping device (not shown) of the injection molding machine first closes the fixed mold 11 and the movable mold 12 with a relatively weak constant clamping force. At this time, as shown in FIG.
The movable plate 26 of the fixed mold 11 and the movable mold plate 42 of the movable mold 12 abut and close. On the other hand, the fixed-side receiving plate 17 and the moving plate 26 of the fixed mold 11 are opened with a predetermined opening amount A1. That is, the mold clamping force and the force of the spring 31 are balanced.
And the cavity insert 36 of the fixed mold 11 is
45 is not fitted and runner 46
And the cavity 13 communicate with each other. Also, movable type
The 12 movable inserts 51 abut against the distal end surface of the cavity insert 36 due to the bias of the spring 56, and are brought into a closed state.

In this state, the nozzle of the heating cylinder device
A molten thermoplastic resin as a molding material is injected from 20 to a sprue 21. This resin is supplied from sprue 21 to runner 46
And the cavity 47 is filled through the gate 47 (filling step). When the cavity 13 is filled with the resin as described above, the opening amount between the fixed-side receiving plate 17 and the movable plate 26 is appropriately increased according to the amount of the resin, and the volume of the cavity 13 is increased. This opening amount depends on the clamping force and the spring.
31 and the pressure of the resin in the cavity 13. Thereby, the pressure of the resin in the cavity 13 is adjusted to be constant (pressure adjustment step). On the other hand, during the filling process including the pressure adjusting process, the movable insert 51 is kept in a state of abutting against the cavity insert 36 by the bias of the spring 56. As described above, as the opening amount between the fixed-side receiving plate 17 and the moving plate 26 changes, the movable insert 51 becomes
It slides with respect to the movable side receiving plate 41.

After the completion of the filling step, the mold clamping device increases the mold clamping force, and the fixed mold 11 and the movable mold 12 are finally closed. At that time, the fixed-side receiving plate 17 and the moving plate 26 of the fixed mold 11 are closed. Along with this, the volume of the cavity 13 decreases, excess resin in the cavity 13 returns to the runner 46 from the gate 47 that is still open, and resin in the mold apparatus returns to the heating cylinder device. Then, as shown in FIG. 2, when the cavity insert 36 starts to fit into the concave portion 45 of the movable mold plate 42, the gate 47 closes, and at this time, a certain amount of resin remains in the cavity 13 (a measuring step). ). Note that, also in this measuring step, the movable insert 51 is kept in a state of abutting against the cavity insert 36 by the bias of the spring 56.

Thereafter, as shown in FIG. 3, the fixed-side receiving plate 17 and the moving plate 26 are closed until they abut against each other, and the resin in the cavity 13 is pressurized and compressed accordingly (compression step). The compression amount is equal to the opening amount A2 between the fixed-side receiving plate 17 and the moving plate 26 at the end of the measuring process. Further, in the compression step, when the pressure of the resin in the cavity 13 increases, the pressure is applied to the distal end surface of the movable insert 51 excluding the convex portion 57, thereby resisting the force of the spring 56,
The movable insert 51 moves and separates from the cavity insert 36. As described above, once the movable nest 51 separates from the cavity nest 36, pressure is also applied to the distal end surface of the convex portion 57 of the movable nest 51, and the movable nest 51 moves reliably, and finally moves. Nest 51
Abuts against the stopper surface 54 of the movable-side receiving plate 42. As a result, the position of the movable insert 51 is regulated to a predetermined position. The gap formed between the movable insert 51 and the cavity insert 36, that is, the IC chip mounting portion of the IC card P
Resin is filled in a portion corresponding to the concave portion P2 of P1. By the above-mentioned compression step, the density of the product is increased, and shrinkage accompanying the solidification due to cooling of the resin is compensated.

After the resin in the cavity 13 is sufficiently cooled and solidified, the fixed mold 11 and the movable mold 12 are
Is opened. Accordingly, the resin in the cavity 13, that is, the molded IC card P and the resin R solidified in the sprue 21 and the runner 46, first separate from the fixed mold 11. Next, a runner ejecting pin (not shown) provided on the movable mold 12 side ejects the resin R solidified in the sprue 21 and the runner 46 to release the resin R from the movable mold 12 and a diagram provided on the movable mold 12 side. A product ejecting pin (not shown) ejects the IC card P and releases it from the movable mold 12. Further, after the resin R and the product P solidified in the sprue 21 and the runner 46 are taken out, the mold is closed again, and the above steps are repeated.

As described above, according to the configuration of the above embodiment, the pressure adjustment process absorbs the error in the amount of the resin supplied from the injection molding machine, and performs the in-mold measurement in the subsequent measurement process. As a result, the amount of resin filled in the cavity 13 can be accurately controlled, and in combination with the subsequent compression step of compressing the resin in the cavity 13,
A highly accurate IC card P with stable quality can be formed.

Further, for the operation of the movable insert 51, the IC chip mounting portion P1 of the IC card P in the cavity 13 is provided.
And the portion corresponding to the concave portion P2, that is, the portion corresponding to the thin portion, is filled with the resin later than the other portions, so that the resin corresponding to the thin portion is still soft within the cavity 13 while still soft. The resin is compressed. Therefore, the compression is smoothly performed without being hindered by the resin corresponding to the thin portion. Thereby, the dimensional accuracy of the formed IC card P is also improved, and the thickness of the IC card P can be made as specified.

Moreover, since the movable insert 51 is operated by the balance between the force of the spring 56 and the pressure of the resin in the cavity 13, the structure for operating the movable insert 51 is simple, and The mold can be manufactured easily and inexpensively.

Next, a second embodiment of the present invention will be described with reference to FIG. Since the injection compression molding method and the injection compression molding die apparatus of the second embodiment have substantially the same configuration as that of the first embodiment, parts corresponding to those of the first embodiment are denoted by the same reference numerals. And description thereof is omitted. In the second embodiment, in the movable mold 12, the movable insert 51 is driven by a hydraulic actuator 61 as a driving means. The hydraulic actuator 61 includes a fixed type 11 and a movable type, which are controlled by a control means 62 including a hydraulic circuit and a computer.
It is controlled in conjunction with the opening and closing of twelve. In addition, as the driving means, in addition to the hydraulic actuator 61,
Any suitable device such as an electric motor can be used.

At the time of molding, during the filling step including the pressure adjusting step, as shown by a chain line in FIG.
The movable insert 51 abuts against the cavity insert 36 of the fixed mold 11 and is closed by the drive of the hydraulic actuator 61 controlled by the hydraulic actuator 61. Thereafter, at an appropriate time such as during the measuring step or at the start of the compression step, the movable insert 51 moves and separates from the cavity insert 36 by driving of the hydraulic actuator 61 as shown by a solid line. Only at this stage, a portion of the cavity 13 corresponding to the thin portion of the IC card P is filled with resin. Accordingly, similarly to the first embodiment, the compression is smoothly performed without being hindered by the resin corresponding to the thin portion.

Further, in the second embodiment, since the movable insert 51 is driven by the hydraulic actuator 61 irrespective of the pressure of the resin in the cavity 13, the movable insert 51 can be reliably operated. . With this, movable nesting 51
Operation timing can be arbitrarily set. That is, the movable insert 51 is separated from the cavity insert 36 at an appropriate time such as during the filling step or the measuring step, not only during the compression step, but also at a portion corresponding to the thin portion of the IC card P in the cavity 13. Can be filled.

Further, the movable insert 51 using the pressure of the resin is used.
In order to operate the movable insert 51, a portion that receives the pressure of the resin in the mold opening / closing direction is necessary, and the movable insert 51 may be abutted against the fixed mold 11 depending on the shape of the thin portion of the product. Can not. On the other hand, if the movable insert 51 is driven by the hydraulic actuator 61 as in the second embodiment, there is no restriction due to the shape of the thin portion.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
In the above embodiment, before the compression step, the movable insert 51 is caused to abut the cavity insert 36 of the fixed mold 11, but the movable insert does not necessarily have to abut the fixed mold, and the movable insert and the fixed There may be gaps between them. Further, in the above-described embodiment, the movable nest 51 that forms the thin portion of the product is assembled to the movable die 12, but the movable nest that forms the thin portion of the product can be assembled to the fixed type. . In the above-described embodiment, the product to be molded is an IC card.
INDUSTRIAL APPLICABILITY The present invention can be used for general molding of products having a thin portion thinner than other portions, in addition to an IC card. Further, in the above embodiment, high pressure injection molding has been described as an example, but the present invention can be used for injection compression molding other than high pressure injection molding.

[0031]

According to the injection compression molding method of the first aspect of the present invention, the first mold of a plurality of molds that open and close to each other approaches and separates from the other second mold. A movable insert for forming a thin portion of the product is assembled, and after the movable insert is filled with the molding material in the cavity in a state of approaching the second mold, the pressure of the resin in the cavity 13 is adjusted to be constant. Sa
And the pressure is adjusted. Then, the second mold is attached to the first mold.
Finally close, the excess resin in the cavity will return
A certain amount of resin remains in the cavity and is measured,
Thereafter, the movable insert is separated from the second mold body, and the resin in the cavity is compressed, so that the resin in the cavity can be compressed while the molding material of the portion corresponding to the thin portion is still soft. The compression can be prevented from being hindered by the molding material filled in the portion corresponding to the portion, and the dimensional accuracy of the molded product can be improved.

According to the injection compression molding die apparatus of the second aspect of the present invention, the movable insert is urged toward the second mold by the spring, and the spring biases the movable insert. When the molding material is filled in the cavity, the movable nest is kept close to the second mold body, and when the molding material in the cavity is compressed, the movable nest is moved by the pressure of the molding material.
And the second mold
Move the moving body on the side of the first mold body in the mold opening / closing direction
The movable body is supported so as to be movable in a range, and
Since it is biased toward the mold, the method according to the first aspect of the present invention can be carried out. Further, by utilizing the pressure of the molding material, the structure for operating the movable insert can be simplified, and The mold can be manufactured easily and inexpensively.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a mold apparatus for injection compression molding according to the present invention during a filling step.

FIG. 2 is a sectional view at the time of a weighing step.

FIG. 3 is a cross-sectional view at the time of a compression step of the same.

FIG. 4 is a sectional view showing a second embodiment of the injection compression molding die apparatus of the present invention.

FIG. 5 is a perspective view of an IC card as a product to be molded.

FIG. 6 is a cross-sectional view showing an example of a conventional injection compression molding die apparatus.

[Explanation of symbols]

11 Fixed mold (second mold) 12 Movable mold (first mold) 13 Cavity 26 Moving plate (moving body) 51 Movable insert 56 Spring (spring) P IC card (product) P1 IC that forms thin part Tip mounting part P2 Concave part forming thin part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/26-45/37

Claims (2)

(57) [Claims] After filling a molding material into a cavity by using a mold device having a plurality of molds that open and close to each other and form a product-shaped cavity therebetween when the mold is closed, the volume of the cavity is reduced. In the injection compression molding method of compressing the molding material in this cavity by making it smaller,
A movable nest that forms a thin portion of a product that approaches and separates from the other second dies and forms a thin portion of the product is movably assembled to a first one of the plurality of dies. After filling the molding material into the cavity while approaching the second mold, the pressure of the resin in the cavity is adjusted to be constant.
The pressure is adjusted, and then the second mold is applied to the first mold.
Finally closed, the excess resin in the cavity will return
A certain amount of resin remains in the cavity and is measured.
It causes separating the rear the movable insert from the second mold body, injection compression molding method characterized by compressing the resin in the cavity. 2. An injection compression molding die apparatus used in the injection compression molding method according to claim 1, comprising a plurality of molds that open and close with each other and form a product-shaped cavity therebetween when the mold is closed. A movable nest forming a thin portion of a product which moves closer to or away from the other second dies to the first one of the plurality of dies is movably assembled. When the cavity is filled with a molding material, the movable insert inserts into the second mold unit by urging the second mold unit with a spring. Closed state is maintained, and when compressing the molding material in the cavity, the movable insert is set to a size separated from the second mold by the pressure of the molding material ,
And moving a moving body on the first mold side of the second mold.
Supports movement in a specified range in the mold opening and closing direction and moves
A mold apparatus for injection compression molding wherein the body is biased toward said first mold body .