JP3160877B2 - Mold equipment for injection molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold apparatus for injection molding a molding material such as a resin.

[0002]

2. Description of the Related Art For example, in injection molding of a thermoplastic resin, a product is formed by filling a molten resin into a product-shaped cavity formed in a mold, and cooling and solidifying the resin. I have to.

In conventional injection molding, a molding machine performs a measuring step, a filling step, and a pressure-holding step. Taking an in-line screw molding machine as an example, in a heating cylinder device, a predetermined amount of melted resin is accumulated at a tip side in a cylinder body while a rotating screw is retracted (a measuring step). Next, the screw is advanced to inject the resin into the mold from the nozzle at the tip of the cylinder body, and the cavity is filled with the resin (filling step). Thereafter, an appropriate pressure is applied to the resin in the cylinder body by a screw to replenish the resin in an amount corresponding to the shrinkage due to cooling into the cavity (pressure keeping step).

On the other hand, the volume of a cavity in a mold is constant. Therefore, the pressure and amount of the resin filled in the cavity are basically determined by the control of the molding machine. Therefore, if there is an error in the control on the molding machine side, an error will occur in the pressure or amount of the resin filled in the cavity. In order to eliminate this error, it is conceivable to precisely control the screw and the like of the molding machine. However, the cause of the error is various such as temperature, variation in properties of the resin itself, and the like. For example, there is a long resin path from the screw to the cavity, but if there is an error that occurs in this resin path, even if the screw is precisely controlled, an error will occur in the pressure and amount of the resin filled in the cavity. Will be. That is, it is difficult to eliminate the error generated in the cavity only by controlling the molding machine.

In the conventional injection compression molding, for example, as described in JP-A-6-71698, after a resin is filled in a cavity, some components of a mold are removed. By reducing the volume of the cavity itself by moving it or switching the mold clamping force,
The resin in the cavity is compressed. However, compressing the resin by reducing the volume of the cavity does not have the effect of eliminating errors in the pressure and amount of the resin filled in the cavity.

In the case of performing compression after closing a gate from a resin passage to a cavity in injection compression molding, in a conventional mold apparatus, a means for closing the gate and a means for compression are separated. Was. On the other hand, in the mold apparatus described in JP-A-6-71698, means for closing the gate and means for compression are shared. As a configuration for this, a sleeve is movably incorporated in the fixed mold plate in the mold opening and closing direction, and this sleeve is pushed toward the movable mold by the buffer, and the cavity is formed between the concave mold of the fixed mold plate and the movable mold plate. It is formed so as to have a convex shape. First, the mold is closed with a weak mold clamping force, and the movable mold plate and the sleeve abut, but the fixed mold plate and the movable mold plate are slightly open, and the concave mold and the convex mold are fitted. Fill the cavity with resin without any. Next, when the fixed mold plate and the movable mold plate are closed by increasing the mold clamping force, the gate is closed by the fitting of the concave mold and the convex mold, and the compression is performed.

However, in the mold apparatus described in the above publication,
Since the resin passage to the cavity is formed by the gap between the fixed mold plate and the movable mold plate, the resin in the resin passage is closed with closing the fixed mold plate and the movable mold plate. , It must either enter the cavity while being compressed or return to the molding machine. Even if the resin in the resin passage can return to the molding machine side, the resin in the resin passage is compressed around the cavity by the fixed mold plate and the movable mold plate. And the pressure are unstable.

[0008]

As described above, in the conventional injection molding method, the pressure and amount of the molding material such as resin filled in the cavity are controlled by controlling the material supply device such as a heating cylinder device. Therefore, there is a problem that it is difficult to accurately control the pressure and amount of the molding material. Also, as a mold apparatus for injection compression molding, JP-A-6-71698 discloses that a means for closing a gate and a means for compression are commonly used. In the mold apparatus described in (1), the volume of the resin passage, which is a material passage, is also reduced along with the compression operation, so that there is a problem that the amount and pressure of the final molding material in the cavity become unstable. there were.

An object of the present invention is to solve such a problem, and it is an object of the present invention to accurately control the pressure and amount of a molding material filled in a cavity.

[0010]

In order to achieve the above object, the injection molding die apparatus of the present invention opens and closes each other and communicates with each other through a gate through a material passage and the material passage when the mold is closed. A pair of molds forming a cavity are provided. One of the molds is a base, a movable body that is supported by the base in the opening and closing direction of the two molds and abuts against and closes the other mold. And a projection integrally provided on the base and slidably penetrating the moving body. The other mold has a concave portion into which the convex portion of the one mold is removably fitted. And a configuration in which the cavity is formed by the concave portion and the convex portion, the material passage is formed between the moving body and the other mold, and the gate is closed by the convex portion fitted into the concave portion. I do. Further, the moving body is provided with a concave portion surrounding the convex portion and forming the material passage and the gate.

[0011]

In the injection molding die apparatus of the present invention, first, a pair of molds are closed with a weak mold clamping force, and the moving body of one mold and the other mold are closed, and the one mold is closed. In a state where the moving body and the base are open, a filling step of supplying the molding material to the material passage and filling the cavity is performed.

Subsequent to the filling step, the supply of the molding material to the mold apparatus is continued, and the movable body and the other mold body are displaced with respect to the base of one mold body, so that the molding material in the mold apparatus is displaced. A pressure adjustment step is performed to adjust the pressure of the molding material in the cavity by balancing the pressure and the mold clamping force. That is, in this pressure regulation step, the base of one mold, the moving body and the other mold are opened against the mold clamping force by the pressure of the molding material in the mold apparatus. Is determined by the balance between the pressure of the molding material in the mold apparatus and the clamping force, and becomes larger as more molding material is supplied into the mold apparatus. In other words, even if there is an error in the amount of the molding material supplied from the material supply device, the error is absorbed by the change in the opening amount, and the pressure of the molding material in the cavity becomes constant.

After this pressure adjustment step, the mold clamping force is increased to close the base of one mold and the moving body, and the molding material in the cavity is returned to the material supply device side. Perform a metering step of leaving a fixed amount of molding material in the cavity when the gates are closed by fitting with each other. That is, when the pressure adjustment step is completed, the amount of the molding material in the cavity is not constant, but the amount of the molding material in the cavity is made constant by the subsequent measurement step. Thus, the pressure adjustment step and the metering step accurately control the pressure and amount of the molding material filled in the cavity.

After this measuring step, that is, after the gate is closed, the base of one mold and the moving body are closed until they abut against each other, and a compression step of compressing the molding material in the cavity is performed. Thereby, the shrinkage accompanying the solidification of the molding material is compensated, and it is not necessary to perform a pressure-holding step on the material supply device side for this compensation.

By the way, since the material passage to the cavity is formed between the moving body of one mold and the other mold, the pressure of the molding material applied to the base of one mold and involved in pressure regulation is reduced. The pressure is applied to the substrate in the cavity, and the pressure is adjusted based on the cavity. In the measuring step, since the volume of the material passage does not change, the molding material in the cavity returns to the material passage smoothly, and the pressure of the molding material in the cavity is kept constant. Further, the cooling of the molding material in the vicinity of the gate is delayed due to the material passage and the recess forming the gate formed around the protrusion on the moving body. This allows the molding material to return more smoothly from the cavity to the material passage during the metering process.

[0016]

Hereinafter, an embodiment of the present invention will be described.
This will be described with reference to the drawings. The present embodiment is applied to injection molding using a thermoplastic resin as a molding material, and uses an in-line screw type injection molding machine as shown in FIG. In FIG. 6, reference numeral 1 denotes a heating cylinder device which is a material supply device. The heating cylinder device 1 has a substantially cylindrical cylinder body 2.
In the cylinder body 2, a heater 3 for heating is provided on the outer periphery, and a nozzle 4 is provided at a tip portion (left portion in the figure). A hopper 5 is provided on the rear upper side of the cylinder body 2. The screw 6 is accommodated in the cylinder main body 2 so as to be rotatable and movable in the axial direction (left and right directions in the drawing). A piston rod 12 of a hydraulic cylinder 11 is fixedly connected to the rear side of the screw 6. That is, the hydraulic cylinder 11 drives the screw 6 in the axial direction. The screw 6 is connected to the electric servomotor 13
Is driven to rotate. In order to transmit rotation from the servo motor 13 to the screw 6, a spline cylinder 14 fixed to the outer periphery of the piston rod 12
A gear 15 for transmitting rotation is spline-fitted. That is, the gear 15 is prevented from rotating with respect to the screw 6, but can move freely in the axial direction.

Reference numeral 21 denotes a direct-pressure type mold clamping device. The mold clamping device 21 has a fixed platen 22 and a movable platen 23. The movable platen 23 is movable in the horizontal direction in the figure along the tie bar 24 and is driven by a hydraulic cylinder 25 via a mold clamping ram 26. The drive of the hydraulic cylinder 25 is controlled by a drive control device 27 including a servo valve and the like, so that the mold clamping force can be adjusted. The fixed mold 32 of the mold apparatus 31 is attached to the fixed platen 22, and the movable platen
The movable mold 33 is attached to 23. The mold clamping device 21 and the heating cylinder device 1 are comprehensively controlled by a control device such as a computer.

Next, the structure of the mold apparatus 31 will be described with reference to FIGS.
It will be described in detail based on. Note that FIGS. 1 and 3 for describing the operation are simplified for simplicity and may not correspond to the other drawings. 1 to 3
In the above, the resin is indicated by thick lines with hatching. The fixed mold 32, which is one mold, and the movable mold 33, which is the other mold, are opened and closed by the movement of the movable platen 23, and form a product-shaped cavity 34 therebetween when the mold is closed. Note that the product P to be molded is a lens, and the axial direction of the product P coincides with the opening and closing directions of the fixed mold 32 and the movable mold 33.

The fixed mold 32 has a fixed mounting plate 36 mounted on the fixed platen 22 and a fixed receiving plate 37 fixed to the surface of the fixed mounting plate 36 on the movable mold 33 side. The fixed-side mounting plate 36 and the fixed-side receiving plate 37 constitute a base 38. A locate ring 39 and a sprue bush 40 are fixed to the fixed-side mounting plate 36. The sprue bush 40, to which the nozzle 4 of the heating cylinder device 1 is connected, has a sprue 41 as a material passage inside, and protrudes toward the movable mold 33 through the fixed-side receiving plate 37. .

On the movable mold 33 side of the fixed-side receiving plate 37,
A moving plate 46 as a moving body is supported so as to be movable in a predetermined range in the mold opening / closing direction. For this support, guide pins 47 fixed to the fixed-side mounting plate 36 and the fixed-side receiving plate 37 and protruding toward the movable die 33 penetrate the movable plate 46 in a slidable manner. Along with this, a sleeve fixed to the movable mold 33 side of the fixed-side receiving plate 37 together with the stopper 48 by the bolt 49
50 slidably penetrates the moving plate 46. The stopper 48 limits the maximum gap between the movable plate 46 and the base body 38, that is, the maximum opening amount by hitting the movable plate 46 from the movable mold 33 side. Further, the movable plate 46 is urged toward the movable mold 33 with respect to the base body 38 by a spring 51 which is an urging means sandwiched between the fixed-side mounting plate 36 and the movable plate 46 in a compressed state. I have. The tip of the sprue bush 40 is slidably fitted in a through hole 52 formed in the movable plate 46. Note that the moving plate 46 is
a and a block 46b fixed inside the frame 46a.

The base 38 has a fixed mounting plate.
The pin 56 is fixed by being sandwiched between the fixed side receiving plate 37 and the fixed side receiving plate 37.The pin 56 penetrates through the fixed side receiving plate 37 and protrudes toward the movable mold 33. , Moving plate 46
Is slidably fitted in a through hole 57 formed in the hole. The distal end of the pin 56 forms a protrusion 58 that can protrude toward the movable mold 33 from the movable plate 46.

The movable mold 33 has a movable mounting plate 61 attached to the movable platen 23, and a movable receiving plate fixed to a surface of the movable mounting plate 61 on the fixed mold 32 side via a spacer block 62. 63, and a movable mold plate 64 fixed to the surface of the movable receiving plate 63 on the fixed mold 32 side. The movable mold plate 64 includes a frame 64a and a block 64b fixed inside the frame 64a. Also,
The movable die 33 is provided with a guide bush 65 through which the guide pin 47 of the fixed die 32 slidably penetrates. Also,
The movable mold plate 64 abuts against the movable plate 46 of the fixed mold 32 and closes.However, for the purpose of mutual guidance between the movable mold plate 64 and the movable plate 46, the movable plate 46 has guide pins 66.
Are fixed, and the movable mold plate 64 is formed with a through hole 67 into which the guide pin 66 is slidably fitted.

The movable mold plate 64 includes the fixed mold 32.
A concave portion 71 is formed in which the convex portion 58 is removably fitted. The bottom surface of the concave portion 71 is formed by a nest 72 embedded and fixed in the movable mold plate 64. The fitting surface between the convex portion 58 and the concave portion 71 forms a columnar surface parallel to the mold opening / closing direction, and there is almost no gap between them so that the product P does not have burrs. Then, the cavity 34 having the final product shape is formed by the convex portion 58 and the concave portion 71. That is, the tip surface of the convex portion 58 forms one end surface of the product P, the bottom surface of the concave portion 71 forms the other end surface of the product P, and the inner peripheral surface of the concave portion 71 forms the outer peripheral surface of the product P. .

The movable plate 46 of the fixed mold 32 and the movable mold
A runner 76 and a gate 77, which are material passages for connecting the sprue 41 to the cavity 34, are formed between the movable mold plate 64 and the movable mold plate 64. An annular concave portion 78 surrounding the convex portion 58 is formed on the surface of the movable plate 46 on the movable mold 33 side. The recess 78 communicates with the runner 76, and forms a part of the runner 76 and a gate 77 from the runner 76 to the cavity 34. The gate 77 is closed by fitting the projection 58 of the fixed mold 32 into the recess 71 of the movable mold 33. The force by which the spring 51 urges the movable plate 46 is set to a force that keeps the movable plate 46 and the movable mold 33 closed against the pressure of the resin in the runner 76.

Further, a projecting plate 81 is supported between the movable mounting plate 61 and the movable receiving plate 63 so as to be movable in the mold opening and closing direction. The protruding plate 81 has a product protruding pin 82 for protruding the formed product P and a runner 76.
A runner protruding pin 83 that protrudes the resin solidified therein is fixed.

Next, the injection molding method will be described. In the heating cylinder device 1, the plasticizing step and the injection step are repeatedly performed. In the plasticizing step, the thermoplastic resin supplied from the hopper 5 into the cylinder body 1 is melted and plasticized by heating by the heater 3 and kneading by the rotation of the screw 6. Along with this plasticization, the resin is sent forward by the rotation of the screw 6 and is accumulated at the tip side in the cylinder body 1. Accordingly, the screw 6 is retracted by the pressure of the resin. During the plasticizing process, the hydraulic cylinder 11
An appropriate back pressure is applied to the screw 6 in the forward direction. When it is detected that the screw 6 has retreated to a predetermined position, the screw 6 moves forward by driving the hydraulic cylinder 11, and the resin on the tip side in the cylinder main body 1 becomes the nozzle 4.
And is supplied to the sprue 41 of the mold apparatus 31.
When it is detected that the screw 6 has advanced to the predetermined position, or when the screw 6 has advanced to the advance limit,
The plasticizing step is performed again.

The mold clamping device 21 first closes the fixed mold 32 and the movable mold 32 with a weak and constant mold clamping force F1. At this time, FIG.
As shown in (a), the movable plate 46 of the fixed die 32 and the movable die 33 abut and close. On the other hand, the base body 38 of the fixed mold 32 and the moving plate 46 are opened with the initial opening amount A1, but the stopper 48 does not hit the moving plate 46. That is, mold clamping force
F1 and the force G of the spring 51 are balanced. Also, the convex portion 58 of the fixed die 32 is not fitted to the concave portion 71 of the movable die 33,
The open gate 77 allows the runner 76 and the cavity 34 to communicate with each other. In this state, the resin is injected from the heating cylinder device 1 to the sprue 41. This resin is filled into the cavity 34 from the sprue 41 through the runner 76 and the gate 77 (filling step).

Subsequently to the filling step, the screw 6 is set in the heating cylinder device 1 while the mold clamping force is maintained at F1.
The injection process is continued until it is detected that has advanced to the predetermined position, or until the screw 6 has advanced to the advance limit. That is, while the supply of the resin from the heating cylinder device 1 to the mold device 31 continues, the oil pressure is closed by the pressure of the resin in the mold device 31 as shown in FIG. The movable plate 46 against the base body 38 of the fixed mold 32 against the mold clamping force F1 given by the mold clamping device 21.
And the movable mold 33 is displaced in the opening direction. Thereby, the generated internal pressure is released. The enlarged opening amount A2 between the base body 38 and the moving plate 46 is determined by the balance between the pressure of the resin in the mold apparatus 31 and the mold clamping force. More specifically, mold clamping force
The opening amount A2 is determined by the balance between F1 and the force G of the spring 51 and the force H that causes the resin in the mold apparatus 31 to retreat the movable plate 46 and the movable mold 33. This opening amount A2 is determined by the mold
The larger the amount of resin supplied within 31, the larger the size. In other words, even if there is an error in the amount of resin supplied from the heating cylinder device 1, the error is absorbed by the change in the opening amount, and the pressure of the resin in the cavity 34 is adjusted to be constant (pressure adjustment). Process). Thus, the pressure of the resin in the cavity 34 can be accurately controlled.

As the opening amount increases from A1 to A2, the force G of the spring 51 becomes slightly weaker. Further, when the mold clamping ram 26 is pushed back together with the movable mold 33, the mold clamping force given by the hydraulic cylinder 25 also increases. Although it may change slightly, the change in the force G of the spring 51 and the change in the mold clamping force are negligibly small. That is, the pressure G of the resin that balances with the force G of the spring 51 and the mold clamping force, which varies according to the displacement of the movable plate 46 and the movable mold 33, occurs when the cavity having a fixed volume is filled with different amounts of resin. It is much smaller than the pressure variation.

In the pressure adjusting step, the pressure of the resin acting to open the base 38 of the fixed mold 32, the movable plate 46 and the movable mold 33 is applied to the fixed mold 32 in a direction parallel to the mold opening and closing direction. Is the pressure applied to the substrate 38. This is the pressure involved in pressure regulation. On the other hand, in the mold apparatus 31 of the embodiment, since the runner 76 is formed between the movable plate 46 of the fixed mold 32 and the movable mold 33, the base 38, the movable plate 46 and the movable mold 33 are opened. The pressure of the resin acting on the base 38 substantially only in the cavity 34 (to be precise, including the sprue bush 40). Therefore, the pressure is adjusted based on the cavity 34. On the other hand, the pressure of the resin in the runner 76 acts to open the moving plate 46 and the movable mold 33, but the pressure of the resin in the runner 76
The movable plate 46 and the movable mold 33 are kept closed. This is the same in the next measuring step.

After the pressure adjusting step is completed, the mold clamping device 21 increases the mold clamping force to F2. Thereby, the base 38 of the fixed mold 32 and the moving plate
46 closes. Accordingly, excess resin in the cavity 34 returns to the runner 76 from the gate 77 which is still open, and resin in the mold apparatus 31 returns to the cylinder body 2 of the heating cylinder apparatus 1. The screw 6 retreats accordingly. Then, as shown in FIG. 2A, when the convex portion 58 of the fixed mold 32 starts to be fitted into the concave portion 71 of the movable mold 33, the gate 77 closes, and at this time, a certain amount of resin is filled in the cavity 34. It will remain (weighing process).

After the weighing step, as shown in FIG.
The base 38 of the fixed mold 32 and the moving plate 46 are closed until they abut against each other, and accordingly, the resin in the cavity 34 is pressurized and compressed (compression step). The compression amount B is equal to the opening amount A3 between the base 38 and the moving plate 46 at the end of the measuring step.

At the end of the pressure regulation step, the volume of the cavity 34, that is, the amount of resin in the cavity 34 is not constant. However, in the subsequent measurement process, the resin in the cavity 34 returns to the runner 76 as described above, and a certain amount of resin remains in the cavity 34 at the moment when the gate 77 is closed. Thus, by the pressure adjustment process and the measurement process,
The pressure and amount of the resin filled in the cavity 34 will be accurately controlled.

Incidentally, in the mold apparatus 31, the runner
By forming the 76 between the movable plate 46 of the fixed mold 32 and the movable mold 33, the volume of the runner 76 does not change in the measuring step. Therefore, the resin smoothly returns from the cavity 34 whose volume decreases to the runner 76, and the pressure of the resin in the cavity 34 is reliably kept constant. At the same time, the closing operation of the mold can be accelerated.

Further, since a part of the runner 76 and a concave portion 78 forming the gate 77 are formed on the movable plate 46 so as to surround the convex portion 58, the cooling of the resin near the gate 77 is delayed. During the process, the resin returns more smoothly from the cavity 34 to the runner 76. On the other hand, if the recess 78 is not provided and the gate is merely a side gate, the cooling of the resin in the cavity generally proceeds faster at a position close to the dividing surface between the fixed mold and the movable mold. To
Since the cooling and solidification of the resin near the gate also proceeds relatively quickly, there is a possibility that the resin may not return smoothly from the cavity to the runner. In order to sufficiently obtain the effect of the recess 78, it is necessary to make the recess 78 large enough to match the thickness of the product P.

After the gate 77 is closed with the closing of the mold, a compression step is performed, and the resin in the cavity 34 is compressed. However, in the measurement step, a fixed amount of resin is left in the cavity 34 at a constant pressure. Thereby, the compression is performed smoothly.
The compression compensates for shrinkage due to solidification due to cooling of the resin. Therefore, it is not necessary to perform the pressure holding step on the side of the heating cylinder device 1 for this compensation. Of course, compression also has the effect that the cooling time in the mold apparatus 31 can be shortened.

After the resin in the cavity 34 is sufficiently cooled and solidified, the fixed mold 32 and the movable mold
33 is opened. Accordingly, the resin in the cavity 34, that is, the product P, the resin solidified in the runner 76 and the sprue 41, first leaves the fixed mold 32. Next, a projecting rod (not shown) provided on the mold clamping device 21 pushes the projecting plate 81 toward the fixed mold 32, and the runner projecting pin 83 projects the resin solidified in the runner 76 and the sprue 41. The product is released from the movable mold 33, and the product ejecting pin 82 projects the product P to move the movable mold 33.
Release from mold. In addition, runner 76 and sprue 41
After the solidified resin and the product P 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 and amount of the resin filled in the cavity 34 can be easily and accurately determined by the pressure adjusting step and the measuring step performed in the mold apparatus 31. The product P can be controlled and, therefore, a high-precision product P with stable quality can be obtained.

Further, in the mold apparatus 31, since the runner 76 is formed between the movable plate 46 of the fixed mold 32 and the movable mold 33, the pressure is adjusted based on the cavity 34. By smoothly returning the resin in the cavity 34 to the runner 76, the pressure and amount of the resin filled in the cavity 34 can be controlled more accurately.

Further, the movable plate 46 is formed with a recess 78 for forming a part of the runner 76 and the gate 77 so as to surround the convex portion 58, so that the resin in the cavity 34 can be more smoothly removed during the measuring process. Return to runner 76.

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, the case where an in-line screw type injection molding machine is used has been described as an example, but various types of molding machines such as a plunger type may be used. As the mold clamping device, various types such as a toggle type and a direct pressure type as in the above embodiment can be used. The drive source of the mold clamping device is not limited to the hydraulic cylinder, but may be an electric motor or the like. Further, the mold apparatus is not limited to the one in the above embodiment. For example, as the urging means for urging the moving body, an air cylinder or the like can be used in addition to a spring. The product to be molded is not limited to a lens, and the present invention can be applied to molding of products of various shapes.

In the above embodiments, the injection molding of a thermoplastic resin was described as an example. However, the present invention is not limited to the injection molding of ceramics using a thermoplastic resin as a binder, the injection molding powder metallurgy method, or the thermoforming method. It is applicable to injection molding of various molding materials such as injection molding of curable resin.

[0043]

According to the present invention, the movable body and the other mold body are displaced with respect to the base of one mold body, and the pressure adjusting step and the measuring step are performed in the mold apparatus, whereby the cavity is formed. The pressure and the amount of the molding material to be filled can be easily and accurately controlled, and therefore, a high quality product with stable quality can be obtained. In addition, since the material passage to the cavity is formed between the moving body and the other mold, the pressure is adjusted based on the cavity, and the molding material in the cavity smoothly flows to the material passage in the measuring step. Returning allows more precise control of the pressure and amount of molding material that fills the cavity. Further, the movable body surrounds a projection integrally formed with the base forming the cavity by being fitted into the recess of the other mold,
Since the recess forming the material passage and the gate was formed,
By delaying the cooling of the molding material in the vicinity of the gate, the molding material in the cavity can be more smoothly returned to the material passage during the weighing process, and the closing operation of the mold including the compression process can be accelerated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a part of an injection molding die apparatus showing one embodiment of the present invention, wherein (a) shows a filling step and (b) shows a pressure regulating step.

FIG. 2 is a cross-sectional view of a part of the injection molding die apparatus,
(A) shows the time of the measuring step, and (b) shows the time of the compressing step.

FIG. 3 is an enlarged view of the vicinity of the cavity in FIG. 2B.

FIG. 4 is a front view of a part of a fixed mold of the injection molding die apparatus.

FIG. 5 is a cross-sectional view of a movable mold of the injection molding die apparatus.

FIG. 6 is a side view, partially in section, showing the entire apparatus used for injection molding;

[Explanation of symbols]

 31 Mold device 32 Fixed mold (one mold) 33 Movable mold (the other mold) 34 Cavity 38 Base 46 Moving plate (moving body) 51 Spring (biasing means) 58 Convex part 71 Concave part 76 Runner (material passage) ) 77 gate 78 recess

Continuation of the front page (56) References JP-A-63-111023 (JP, A) JP-A-2-1392111 (JP, A) JP-A-3-193428 (JP, A) JP-A-3-203616 (JP) , A) JP-A-4-41217 (JP, A) JP-A-6-71698 (JP, A) JP-A-62-172028 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB Name) B29C 45/26-45/44 B29C 45/56

Claims (1)

(57) [Claims] A pair of molds that open and close to each other and form a material passage and a cavity communicating with the material passage via a gate between the molds when the mold is closed; A movable body that is movably supported in the opening and closing direction of the two mold bodies and abuts against and closes the other mold body; biasing means for biasing the movable body toward the other mold body with respect to the base; A protrusion that is provided integrally and slidably penetrates the moving body; and the other mold has a recess into which the protrusion of the one mold is removably fitted. Forming the cavity by the concave portion and the convex portion, forming the material passage between the moving body and the other mold, the gate is closed by a convex portion fitted in the concave portion, The moving body surrounds the convex portion, and is provided with the material passage and the game passage. Injection mold apparatus characterized by forming the recess to form a.