KR19980023216A - Injection molding apparatus and injection molding mold and injection molding method used in the injection molding apparatus - Google Patents

Abstract

An object of the present invention is to precisely control the pressure and the amount of thermoplastic resin filled in a cavity to obtain a high-precision product with stable quality.

In the mold apparatus used in the present invention, the stationary die includes a base and a movable body that closes and collides with a movable die supported so as to be movable in the opening and closing directions of the stationary and movable dies, the spring being moved in the direction of the movable die. Hold down. The base has a convex portion penetrating the moving body, and the concave portion to which the convex portion is coupled is movable, and a cavity is formed between the convex portion and the concave portion. Runners and gates are formed in the cavity between the movable and movable types.

At the time of molding, the mold is closed by the clamping force, the movable body and the movable mold are closed, and the resin is filled into the cavity while the movable body and the gas are slightly open. At this time, the opening amount of the movable body and the gas is increased by the pressure of the resin, and the pressure of the resin in the cavity is kept constant. Thereafter, the clamping force is strengthened to close the moving body and the gas. During this time, the resin in the cavity returns to the runner, and a certain amount of resin remains in the cavity when the convex portion is joined to the recess and the gate is closed. Thereafter, the resin in the cavity is compressed.

Description

Injection molding apparatus and injection molding mold and injection molding method used in the injection molding apparatus

The present invention relates to, for example, an injection molding apparatus for molding materials such as resin, a mold apparatus used for the injection molding apparatus, and an injection molding method, in particular, for blocking the gate and compressing the molding material in the cavity. .

For example, in injection molding of thermoplastic resins, a molten resin is filled into a cavity of a product form formed in a mold apparatus, cooled, and solidified to form a product.

In the conventional injection molding, a molding machine performs a metering step and a pressure holding step. If an inline screw type molding machine is adopted as an example, the rotating screw is retracted in the heating cylinder device, and the molten resin is contained at a front end side in the cylinder body (measurement step). Next, the screw is advanced, the resin is injected into the mold apparatus from the nozzle of the tip of the cylinder body, and the resin is discharged into the cavity (charging step). Thereafter, an appropriate pressure is added to the resin in the cylinder body by a screw, and the resin of the shrinkage by cooling is replenished in the cavity (pressure holding step).

On the other hand, the volume of the cavity in the mold apparatus is constant. As a result, the pressure and the amount of the resin to be filled in the cavity are basically determined by the control on the molding machine side. For this reason, if there exists an error in the control of the molding machine side, an error will arise in the pressure or quantity of resin filled in the cavity at that time. In order to eliminate this error, it is considered to precisely control the screw of the molding machine and the like, but the causes of the error are various, such as changes in temperature and the properties of the resin itself. For example, although there is a long resin passage from the screw to the cavity, if there is an error occurring in the resin passage, even if the screw is temporarily controlled precisely, an error may occur in the pressure or amount of the resin filled in the cavity. It becomes. As a result, it is difficult to solve the error which arises in a cavity only by control of a molding machine.

In the injection molding compression that has been conventionally performed, for example, as described in Japanese Patent Laid-Open No. 6-71698, after filling a cavity with a resin, a part of the mold apparatus is moved, The resin in the cavity is compressed by reducing the volume of the cavity itself by switching the clamping force. However, compressing the resin by reducing the volume of the cavity does not have the effect of eliminating the error of the pressure and the amount of the resin filled in the cavity.

By the way, when compression is performed by closing the gate from the resin passage to the cavity in the injection molding compression, the conventional mold apparatus separates the means for closing the gate from the means for compression. On the other hand, in the mold apparatus described in JP-A-6-71698, the means for closing the gate and the means for compression are shared. In this configuration, the sleeve is pushed to the stationary side plate in the mold opening and closing direction, and the sleeve is pushed in the direction of the movable die by a spring, and the cavity is formed by the convex portion of the stationary side plate and the recess of the plate. To form. Then, the weak mold clamping force is closed, and the movable side plate and the sleeve collide, but when the fixed side plate and the movable side plate are closed, the gate is closed and the compression is performed by engaging the concave and convex parts.

However, in the mold apparatus described in the above publication, since the resin path to the cavity is formed by the gap between the fixed side plate and the movable side plate, the fixed side plate and the movable side plate are closed. The resin in one resin passage enters the cavity while being compressed, but must return to the molding machine side. Even if the resin in the resin passage returns to the molding machine side, since the resin in the resin passage is compressed by the fixed side plate and the movable side plate around the cavity, the final amount and pressure of the resin in the cavity are unstable. do.

In addition, the above publication discloses nothing about the means for sealing the resin passage formed between the fixed side plate and the movable side plate from the outside. Although the guess is limited from the description of drawings, in the mold apparatus described in the above publication, the resin in the resin passage leaks outward.

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

In order to achieve the above object, the present invention includes a first body and a second body having cavities therebetween at the time of closing and closing each other, wherein the first body is a gas and the base described above. A movable body which is in contact with and closed by the above-mentioned second body, which is movably supported in the opening and closing direction of the first body and the second body, and spring means for pushing the body in the direction of the above-mentioned second body with respect to the gas. The volume of the cavity is changed by the opening and closing of the moving body and the gas in the form where the second body and the moving body are closed, and the moving body and the gas are closed. A mold apparatus is used in which the gate from the material passage to the cavity is closed.

Moreover, the material supply apparatus which supplies a plastic-form molding material to the said material path | pass of the said mold apparatus, the said 1st body form and the said 2nd body form of the said mold apparatus can be opened and closed, and a clamping force can be adjusted. Use the clamping device.

Then, the first body and the second body are closed by the weak clamping force, the movable body and the second body are closed, while the movable body and the gas are closed. By this, the molding material is supplied to the material passage of the mold apparatus and filled in the cavity (filling step). At this time, by the balance of the pressure of the molding material in the mold apparatus and the clamping force, the movable body and the second mold body with respect to the gas are displaced, and the pressure of the molding material in the cavity is adjusted ( Pressure adjustment process).

After the supply stop of the molding material in the material supply device, the clamping force is strengthened to close the gas and the moving body. In the meantime, the above-mentioned molding material on the cavity side returns to the above-mentioned material supply device side, and a certain amount of the molding material remains in the above cavity at the time when the gate is closed (measurement step). The gas and the moving body are closed until they collide with each other, and the molding material in the cavity is compressed (compression step).

By the above compression process, even if there is an error in the amount of molding material supplied by the material supply device, the error is absorbed by the displacement of the moving body and the second body with respect to the gas, and the pressure of the molding material in the cavity is constant. Done. On the other hand, at the time when the pressure adjusting step is completed, the amount of the molding material on the cavity side becomes constant as the gas and the mobile body are closed, but in the subsequent metering step, the molding on the cavity side as the gas and the mobile body is closed When the material returns to the material supply device side and the gate is closed, a certain amount of molding material remains in the cavity side. In this way, the pressure and the pressure of the molding material to be filled to the cavity side are easily and accurately controlled by the pressure adjusting step and the metering step. As a result, a high quality product with stable quality can be obtained. In addition, after the gate is closed, the molding material in the cavity is compressed, so that shrinkage is compensated for by the solidification of the molding material, and for this compensation, it is not necessary to perform pressure holding control on the material supply device side.

As a specific form by the above-mentioned metal mold | die apparatus, the following are possible. For example, the base body integrally holds the recessed portion, and the second body has a convex portion in which the recessed portion of the first body is freely coupled, and the cavity described above is formed by these recessed portions and the convex portion. Is formed, and the gate is closed by the convex portion coupled to the concave portion. The material passage is formed between the movable body and the second body. Further, the force for pushing the movable member by the spring member made of a spring or the like is set to a force that maintains the closed form of the movable body and the second mold body in response to the pressure of the molding material in the material passage. do.

In this way, if the material passage is formed between the movable body and the second body, in addition to the gas, the pressure of the molding material related to the pressure is added to the gas only in the cavity, and the pressure is adjusted based on the cavity. . On the other hand, the pressure of the molding material in the material passage acts to close the movable body and the second mold body, but the spring means resists the pressure, and the movable body and the second mold body are kept in the closed form. In addition, in the metering step, since the volume of the material passage does not change, the molding material in the cavity smoothly returns to the material passage, and the pressure of the molding material in the cavity is kept constant. As a result, coordination and metering can be made more accurate.

In addition, the above-mentioned mold apparatus may hold the overflow portion cut off from the above-mentioned cavity over approximately the entire circumference of the above-mentioned cavity when the above-mentioned convex portion engages the above-mentioned concave portion. For this purpose, for example, a periphery which surrounds the convex portion and forms the overflow portion together with the material passage and the gate may be formed in the movable body through which the concave portion slides smoothly.

If there is such an overflow part, the gas and the molding material flow out from the periphery of the cavity to the overflow part during the filling process, thereby improving the fluidity of the molding material in the periphery of the cavity, and smoothly to the periphery of the cavity. And also preferably the molding material is filled. Thereby, characteristics, such as a dimension in the periphery of the product to be shape | molded, can be improved. Thereafter, in the metering step, the molding material in the cavity returns to the material passage through the gate or flows out to the overflow part. After the gate is closed and the overflow portion and the cavity are blocked from each other, the molding material in the cavity is compressed.

Moreover, by the overflow part, the molding material is cooled in the peripheral part of a cavity. As a result, the molding material flows more smoothly from the cavity into the material passage or the overflow portion at the time of the metering step, and the mold closing operation for performing the compression step can be also performed quickly.

Fig. 1 is a sectional view of a part of a mold apparatus used in the first embodiment to which the present invention is applied to molding a roller, and shows a filling process.

FIG. 2 is a cross-sectional view of a part of the same metal mold as in FIG. 1, showing a pressure adjusting step. FIG.

FIG. 3 is a cross-sectional view of a part of the same mold as in FIG. 1, showing a metering step. FIG.

4 is a cross-sectional view of a part of the same mold as in FIG. 1, showing a compression step.

FIG. 5 is an enlarged view of the vicinity of the cavity of the mold apparatus of FIG. 4.

FIG. 6 is a bottom view of the vicinity of the protruding portion of the mold apparatus of FIG. 4.

Fig. 7 is a side view showing, in cross section, a portion showing an outline of the entire apparatus used in the first embodiment of the present invention.

8 is a cross-sectional view of a part of a mold apparatus used in the second embodiment in which the present invention is applied to molding a lens.

Fig. 9 is a sectional view of a part of a mold apparatus used in the third embodiment in which the present invention is applied to the molding of a substrate of an IC card.

FIG. 10 is a perspective view showing an IC card molded by the mold apparatus shown in FIG.

Fig. 11 is a sectional view of a part of the mold apparatus used in the fourth embodiment applied to the molding of the roller holder, showing the time of filling processing.

FIG. 12 is a cross-sectional view of a part of the same mold apparatus as in FIG. 11 and shows the measurement process.

FIG. 13 is a cross-sectional view of a part of the same mold apparatus as in FIG. 11, showing a compression process, and the cross section is different from that of FIG. 11 and FIG.

FIG. 14: is a front view which shows the roller holder shape | molded by the metal mold | die apparatus shown in FIGS. 11-13, and is made into bisected cross section.

FIG. 15 is a side view of the roller holder shown in FIG. 14, and has a bisected cross section.

1 to 7 show a first embodiment of the present invention. This embodiment is applied to injection molding using thermoplastic resin as a molding material, and uses an in-line screw injection molding machine as shown in FIG. In Fig. 7, reference numeral 1 denotes a heating cylinder device in the material supply device. This heating cylinder device 1 has a substantially cylindrical cylinder body 2. In the cylinder body 2, the heater 3 for heating is provided on the outer periphery, and the nozzle 4 is provided in the front-end | tip part (shown on the left side of a figure). Moreover, the hopper 5 is provided in the upper part upper side of the cylinder main body 2. As shown in FIG. In the cylinder body 2, the screw 6 is rotatably housed in the axial direction (shown in the right direction of the drawing). On the rear side of this screw 6, the piston rod 12 of the hydraulic cylinder 11 is fixed and connected. In other words, the hydraulic cylinder 11 drives the screw 6 in the axial direction. The screw 6 is pivotally driven by the electric servomotor 13.

In order to transmit rotation from this servomotor 13 to the screw 6, the rotation transmission gear 15 is spline-coupled to the spline cylinder 14 fixed to the outer periphery of the piston rod 12. As shown in FIG. That is, the gear 15 is prevented from rotating relative to the screw 6, but moves freely in the axial direction.

Reference numeral 21 is a direct pressure clamping device, which holds the fixed side platen 22 and the movable side platen 23. This movable side platen 23 is movable along the tie bar 24 in the right direction shown in the drawing, and is provided by the hydraulic cylinder 25 via the mold ram 26. It is driven. In this hydraulic cylinder 25, the drive is controlled by the drive control device 27 which consists of a servo valve etc., and it is possible to adjust a clamp force. The same movable die 33 is attached to the fixed side platen 22. In addition, the mold clamping device 21 and the heating cylinder device 1 are controlled integrally by a control device such as a computer.

In addition, the structure of the metal mold | die 31 is demonstrated in detail based on FIG. In addition, in FIG. 1 thru | or 6, it is resin represented by the hatching of a thick line. The fixed die 32, which is the first die, and the movable die 33, which is the second die, open and close to each other by the movement of the movable side platen 23, and form a product-shaped cavity 34 between each other at the time of mold closing. It is. Moreover, the product to be shape | molded is the cylindrical roller 101, The axial direction is matched in the mold opening-closing direction of the stationary die 32 and the movable die 33. As shown in FIG.

The stationary die 32 is a stationary side attachment plate 36 attached to the movable side platen 23 and a stationary side support fixed to the surface of the stationary die 33 side of the stationary side attachment plate 36. The plate 37 is held, and the substrate 38 is constituted by the fixed side attachment plate 36 and the fixed side support plate 37. Also, a location ring 39 and a quadrilateral bush 40 are fixed to the fixed side attachment plate 36. The quadrilateral bush 40 is connected to the nozzle 4 of the heating cylinder device 1, is a spool 41 having a material passage inside, and moves through the fixed side support plate 37. It protrudes toward the mold 33 side.

The movable chain moving plate 46 is supported on the movable mold 33 side of the fixed side support plate 37 so as to be movable in a predetermined range in the mold opening and closing direction. For this support, the sleeve 50 is fixed to the movable mold 33 side of the fixed side support plate 37 and the sleeve 50 fixed by the bolt 49 freely slides the movable plate 46. Penetrating to move. In addition, the stopper 48 contacts the movable plate 46 from the movable die 33 side to regulate the maximum gap between the movable plate 46 and the base 38, that is, the maximum opening amount. will be. In addition, the movable plate 46 is pushed against the base 38 in the direction of the movable die 33 by the spring 51 sandwiched between the fixed side attachment plate 36 and the movable plate 46 in a compressed form. I put it. In addition, the tip portion of the quadrilateral bush 40 is freely slidably coupled to the through hole 52 formed in the movable plate 46.

In addition, although the sleeve 56 is fixed to the base body 38 by the fixed side attachment plate 36 and the fixed side support plate 37, the sleeve 56 has a fixed side support. It protrudes through the plate 37 to the movable die 33 side, and the front end side of the sleeve 56 is freely slidably coupled to the through hole 57 formed in the movable plate 46. The tip end of the sleeve 56 does not have a recess 58 that protrudes toward the movable die 33 side from the movable plate 46.

The movable die 33 is provided with a spacer plate 62 on the movable side attaching plate 61 attached to the movable side platen 23 and the surface of the movable die attaching plate 61 on the fixed mold 32 side. The movable side support plate 63 fixed through it and the movable side plate 64 fixed to the surface by the side of the stationary die 32 of this movable side support plate 63 are hold | maintained. The movable side plate 64 is in contact with the movable plate 46 of the stationary die 32 described above and closes, but the movable side plate 64 and the movable plate 46 are moved to guide each other. A guide pin 66 is fixed to the plate 46, and a through hole 67 is formed in the movable side plate 64 to which the guide pin 66 slides freely.

In the movable side plate 64, a convex portion 71 into which the concave portion 58 of the fixed mold 32 is coupled is inserted. Moreover, the pin part 73 formed in the core 72 embedded in the movable side plate 64 and being fixed protrudes coaxially in the convex part 71. The pin portion 73 is inserted into and detached from the sleeve 56 forming the concave portion 58 of the fixed mold 32 described above. The mating surface of the concave portion 58 and the convex portion 71 and the mating surface of the pin portion 73 and the sleeve 56 do not have a main surface parallel to the mold opening and closing direction and are formed. There is little gap between each other so that burr does not generate | occur | produce in the roller 101. FIG. The cavity 34 of the final product form is formed by the concave portion 58 and the convex portion 71. That is, the front end surface of the concave portion 58 forms one end surface of the roller 101, the bottom surface of the convex portion 71 forms the other end surface of the roller 101, and the inner circumferential surface of the convex portion 71 is the roller. An outer circumferential surface of 101 is formed, and the pin portion 73 forms an inner circumferential surface of the roller 101.

In addition, the runner which is a material passage which communicates the above-mentioned spool 41 to the cavity 34 between the movable plate 46 of the closed fixed mold 32 and the movable side plate 64 of the movable mold 33 ( 76 and gate 77 are formed. On the surface of the movable plate 46 on the movable die 33 side, a circular periphery surrounding the recess 58 is formed, whereby an overflow portion (a) along the entire circumference of the cavity 34 is formed. 78) is formed. The overflow portion 78 communicates with the runner 76 described above, and may form a part of the runner 76 and a gate 77 from the runner 76 to the cavity 34. . The gate 77 is closed by engaging the concave portion 58 of the stationary die 32 with the convex portion 71 of the movable die 33. Moreover, the force which the spring 51 pushes the moving plate 46 is set to the force which keeps the moving plate 46 and the fixed form 33 closed in response to the pressure of resin in the runner 76. As shown in FIG.

Furthermore, an injector plate (not shown) is supported between the movable side attaching plate 61 and the movable side support plate 63 so as to be movable in the mold opening and closing direction. The injector plate 82 which protrudes the molded roller 101 and the runner injector pin 83 which protrude the resin solidified in the runner 76 are being fixed to this injector plate.

The heating cylinder device 1, the mold clamping device 21, and the mold device 31 having the above-described configuration, together with a control device such as a computer, charge control means for carrying out the charging step described below, and a pressure adjusting step A pressure control step for carrying out, a weighing step for carrying out the weighing step, and a compression control means for carrying out the compression step are constituted.

In addition, the injection molding method will be described. In the heating cylinder device 1, the plasticization process and the injection process are repeatedly performed. In the plasticization 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 rotation of the screw 6. Simultaneously with this plasticization, resin is sent forward by the rotation of the screw 6 and is contained in the front end side in the cylinder body 1. As a result, the screw 6 is retracted by the pressure of the resin. In addition, during the plasticization step, a suitable back pressure forward is applied to the screw 6 by the compression cylinder 11. When it is detected that the screw 6 has been retracted to a predetermined position, the screw 6 is retracted by the driving of the compression cylinder 11, and the resin in the cylinder body 1 is injected from the nozzle 4, and the mold apparatus ( 31 is supplied to the spool 41. When it is detected that the screw 6 has advanced to a predetermined position or when the screw has advanced to the mechanical advance limit, the plasticization step is again performed.

The clamping device 21 first closes the stationary die 32 and the movable die 33 with a weak constant clamping force. At this time, as shown in FIG. 1, the movable plate 46 of the stationary die 32 and the movable die 33 contact and close. On the other hand, although the base 38 and the movable plate 46 of the fixed mold 32 are opened with the initial closing amount A1, the stopper 48 does not contact the movable plate 46. That is, the clamping force and the force of the spring 51 is coupled. The concave portion 58 of the stationary die 32 is not coupled to the convex portion 71 of the movable die 33. The runner 76 and the cavity 34 communicate with each other by the closed gate 77. have. In this state, resin is injected into the spool 41 from the heating cylinder device 1. This resin is filled in the cavity 34 from the spool 41 via the runner 76 and the gate 77 (charging step).

Even after the cavity 34 is filled with resin, in the heating cylinder device 1, the injection is performed until the detection of the advancement of the screw 6 to the predetermined position or the advancement of the screw 6 to the advance limit. The process continues, and the supply of resin to the mold apparatus 31 is still continued up to the heating cylinder 1. Meanwhile, the clamping force remains weak. Therefore, due to the pressure of the resin in the mold apparatus 31, as shown in FIG. 2, the inlet / outlet in the hydraulic cylinder 25 is not stopped and the clamping force applied by the mold clamping apparatus 21 is fixed. The movable plate 46 and the movable die 33 with respect to the base 38 of the 32 are displaced in the opening direction.

The enlarged opening amount 42 between the base 38 and the moving plate 46 is determined by the balance between the pressure of the resin in the mold apparatus 31 and the clamping force. More specifically, the opening amount 42 is determined by the combination of the clamping force and the force of the spring 51 and the force of the resin in the mold apparatus 31 to retract the movable plate 46 and the movable mold 33. do. This opening amount 42 is increased so that more resin is supplied into the mold apparatus 31. 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 above-described change in the amount of opening, and the pressure of the resin in the cavity 34 is adjusted to be constant (regulation pressure). fair). In this way, the pressure of the resin in the cavity 34 can be accurately controlled.

In addition, as the opening amounts A1 to A2 are increased, the force of the spring 51 is slightly weakened, and the pressure cylinder 26 is returned by returning the mold ram 26 together with the movable mold 33. The clamping force given by 25) also changes slightly, but the force of these springs 51 and the change of the clamping force are small in the range not seen. That is, the scattering of the pressure of the resin coupled with the force or the clamping force of the spring 51 which changes in response to the displacement of the movable plate 46 and the movable die 33 is filled with a different amount of resin in a cavity of a constant volume. It is very small compared to the dispersion of pressure generated at one time.

In the pressure adjusting step, the pressure of the resin acting to open the base 38, the movable plate 46, and the movable mold 33 of the fixed mold 32 is in the mold opening and closing direction with respect to the fixed mold 32. This is the pressure acting on the gas 38 in the direction parallel to. This is the pressure with respect to the pressure. In contrast, in the mold apparatus 31 of the above-described embodiment, the runner 76 is formed between the movable plate 46 of the stationary die 32 and the movable die 33, and moves with the base 38. The pressure of the resin acting to open the plate 46 and the movable mold 33 acts on the gas 38 only in the cavity 34 (exactly including the quadrilateral bush 40). . As a result, the pressure is set based on the cavity 34. On the other hand, while the pressure of the resin of the runner 76 acts to open the movable plate 46 and the movable mold 33, the force of the spring 51 opposes the pressure of the resin in the runner 76, and the movable plate The 46 and the movable die 33 remain closed. This is the same also in the next measurement process.

After completion of the pressure adjusting step, the clamping device 21 strengthens the clamping force. As a result, the base 38 and the movable plate 46 of the stationary die 32 are closed. As a result, the remaining resin in the cavity 34 returns to the runner 76 from the gate 77 which is kept open, or flows out to the overflow portion 78 and the resin in the mold apparatus 31. Returns to the cylinder body 2 of the heating cylinder 1. This part, the screw 6, returns. As shown in FIG. 3, the concave portion 58 of the stationary die 32 is joined to the convex portion 71 of the movable die 33 and the gate 77 is opened at the same time. The cavity 34 is cut off, and at this point, a certain amount of resin remains in the cavity 34 (measurement step).

After the metering step, as shown in FIG. 4, the base 38 of the stationary mold 32 and the movable plate 46 are closed until they come into contact with each other, whereby the resin in the cavity 34 is pressed and compressed. (Compression process). This compression amount B is equal to the opening amount A3 between the gas 38 and the moving plate 46 at the end of the metering step.

At the time when the above-mentioned pressure adjusting step is completed, the volume of the cavity 34, that is, the amount of resin in the cavity 34 is not constant. However, in the subsequent metering process, as described above, the resin in the cavity 34 returns to the runner 76, and at the moment when the gate 77 is closed, a certain amount of resin remains in the cavity 34. In this manner, the pressure and the amount of the resin filled in the cavity 34 are precisely controlled by the pressure adjusting step and the metering step.

As a result, in the mold apparatus 31, the runner 76 is formed between the movable plate 46 of the stationary die 32 and the movable die 33, so that the runner 76 is in the weighing process. The volume does not change. Therefore, resin returns smoothly from the cavity 34 whose volume is small to the runner 76, and the pressure of resin in the cavity 34 is kept exactly constant. At the same time, the mold lung can be operated quickly.

In addition, an overflow portion 78 is formed on the movable plate 46 to form a part of the runner 76 and the gate 77 by surrounding the recess 58. Cooling of the periphery of the cavity 34 is delayed, whereby the resin returns more smoothly from the cavity 34 to the runner 76 at the time of the metering process. On the other hand, if there is no overflow portion 78, the gate becomes a simple side gate, and in general, the cooling and fixing of the resin in the cavity cause the position near the periphery of the cavity to be advanced more quickly. There is a fear that the resin may not return smoothly from the cavity to the runner. Moreover, in order to fully exhibit the effect of the above-mentioned overflow part 78, it is necessary to make the overflow part 78 size suitable for the thickness of the roller 101. FIG.

After the gate 77 is closed due to mold closing, the process is a compression process, and the resin in the cavity 34 is compressed. However, in the metering process, a certain amount of pressure remains in the cavity 34, thereby compressing the resin. Is also carried out smoothly. By compression, shrinkage due to solidification by cooling of the resin is compensated for. As a result, for this compensation, it is not necessary to perform the pressure holding step toward the heating cylinder device 1 side. Of course, the compression also has the effect of allowing the solidification of the resin in the cavity 34 to be accelerated.

After the resin in the cavity 34 is sufficiently cooled and solidified, the stationary die 32 and the movable die 33 are closed by the mold clamping device 21. Accordingly, the resin in the cavity 34, that is, the resin solidified in the roller 101, the runner 76, and the spool 41, is first separated from the fixed mold 32. Subsequently, it is driven by an injector device not shown in the drawing provided on the mold clamping device 21 side, and the runner injector pin 83 protrudes the solidified resin in the runner 76 and the spool 41 to move the mold. Simultaneously with the release from 33, the product injector pin 82 protrudes from the roller 101 to release from the movable die 33. Further, after the solidified resin and the roller 101 in the runner 76 and the spool 41 are taken out, mold closing is performed again, and the above steps are repeated.

In the above embodiment, the molded product is a roller 101, but the present invention can be applied to molding various products. The second embodiment shown in FIG. 8 applies the present invention to the molding of a maniscus optical lens 102, and the third embodiment shown in FIG. 9 shows the substrate 103 of the IC card. This invention is applied to shaping | molding. In addition, the same code | symbol is attached | subjected to the part corresponding to the metal mold | die apparatus of 1st Example shown in FIG. 1 thru | or 7 mentioned above, and the description is abbreviate | omitted. 8 and 9, only the vicinity of the cavity 34 is described, but the configuration of the entire mold apparatus is the same as the mold apparatus of the first embodiment. 10, the board | substrate 103 of the IC card shape | molded is shown. The substrate 103 of the IC card has a thin flat plate shape, and a recessed IC chip mounting portion 104 is formed on one surface thereof.

Since the lens 102 and the substrate 103 of the IC card do not have through holes, the sleeve 56 of the mold apparatus of the first embodiment is solid in the mold apparatus of the second and third embodiments. Instead of one pin-shaped or block-shaped particle 86, the particle 86 and the core 72 of the movable type 33 do not bond with each other. The molding method is also the same as in the first embodiment. 8 and 9 show a state in which the gate 77 is closed by the convex portion 58 of the tip portion of the particle 86 bonded to the concave portion 71 of the movable die 33 after the compression process is completed. Although shown in FIG. 8 and FIG. 9, the dashed-dotted line shows the position of the particle | grains 86 when the gate 77 is enclosed by the filling process, the pressure regulation process, or the measurement process.

Industrial Applicability The present invention is suitable for molding a product such as the lens 102 that requires high precision, and also improves the optical characteristics of the lens 102. In addition, the overflow portion 78 is particularly effective for relatively thin products such as the lens 102 and the substrate 103 of the IC card. In normal injection molding, when the resin is filled in the cavity from the gate, the filling of the resin is deteriorated because execution is stopped at the periphery of the cavity. In addition, the front end of the flow of the resin may be rapidly solidified by cooling, and the product characteristics may deteriorate due to distortion of residual stress or the like even without insufficient filling. For example, a defect may occur such that the thickness of the peripheral portion of the product becomes slightly thicker than the thickness of other portions.

Moreover, in injection molding, the gas (air and gas of the resin) in the cavity has to be extracted as the resin is filled with the resin in the cavity, so that a gas vent is applied to the contact surface between the fixed mold and the movable mold. Although a small gap is formed, a burr is generated when the gas band is set with a large interstitial dimension to pass. On the other hand, a burr occurs when a small interstitial dimension is set to pass. In contrast, in the present invention, when the filling process is performed, gas and resin flow out of the cavity 34 from the cavity 34 to the overflow portion 78, whereby a gas vane is reliably generated, and the cavity 34 is formed. By improving the fluidity of the resin in the periphery of the resin, the resin is satisfactorily filled to the periphery of the cavity 34. Thereby, distortion of the residual stress of the peripheral part of a product can be reduced, and characteristics, such as the dimension of the peripheral part of a product, can be improved. In addition, the overflow portion 78 is finally blocked from the cavity 34 by engaging the convex portion 58 of the fixed mold 32 to the recessed portion 71 of the movable mold 33. It is not intended to produce burrs in the product.

Further, the fourth embodiment shown in Figs. 11 to 15 applies the present invention to a roller holder 106 used as a prepayment of a roller pen of stationery. As shown in FIG. 14 and FIG. 15, the roller holder 106 holds a cylindrical main body 107 in the lower portion and has a stepped portion bent inward in the radial direction from the upper end of the main body 107. 108 is held, and a thin cylindrical tapered portion 109 protruding upward from the inner circumference of the step portion 108 is held. Moreover, inside the taper part 109, the branch part 110 which transverses this in the axial direction is hold | maintained.

In the case where the roller holder 106 having such a shape is molded by ordinary injection molding, in particular, a thin taper portion 109 or the like causes a filling failure. In addition, due to shrinkage due to cooling, a sink mark may occur on the outer surface of the tapered portion 109, particularly in a portion where the bridge portion 110 is screwed. Such a problem can be solved by applying the present invention.

The mold apparatus of the fourth embodiment for forming the roller holder 106 basically has the same configuration as the mold apparatus of the first embodiment described above, and the corresponding parts are given the same reference numerals, and the description thereof will be described. Omit. In the mold apparatus of the fourth embodiment, a product forming surface 91 is formed inside the tip portion of the sleeve 56 to form the outer surface of the tapered portion 109 of the roller holder 106. In the inner surface of the sleeve 56, a hole portion 92 continuous to the product forming surface 91 is formed. Furthermore, the pin 93 is fixed to the base 38 by the fixed side attachment plate 36 and the sleeve 56. And although the protrusion piece 94 is formed in the front-end | tip part of this pin 93, this protrusion piece 94 is inserted in the hole part 92 of the sleeve 56 mentioned above.

On the other hand, the core 72 of the movable die 33 is provided with a protrusion 96 that coaxially penetrates the inside of the recess 71 and protrudes in the direction of the stationary die 32. The protruding portion 96 forms an inner surface of the roller holder 106 including the tapered portion 109 by its outer surface. The distal end of the protruding portion 96 is an engaging portion 97 that is engaged with the hole 92 of the sleeve 56 of the fixed mold 32 as described above. Moreover, the slitting part 98 is formed in the front-end | tip side of the protrusion part 96 containing this engaging part 97. As shown in FIG. This slit part 98 is pulled out by a pair of side surface and front end surface of the protrusion part 96, and the protrusion part 94 of the pin 93 of the fixed mold | type 32 mentioned above engages at the time of mold closing. In this way, the above-described protruding portion 96 penetrates into the tapered portion 109 of the roller holder 106 to be formed and protrudes from the tip opening of the tapered portion 109. The engaging surface of the convex portion 71, the engaging surface of the hole portion 92 and the engaging portion 97, and the engaging surface of the protrusion piece 94 and the slit portion 98 are parallel to the mold opening and closing direction. There is little gap between each other so as not to retain the main surface and to generate burrs in the roller holder 106 to be formed.

The injection molding method using this mold apparatus is also basically the same as in the first embodiment. That is, first, the mold is closed by a relatively weak clamping force and charged. However, at this time, as shown in FIG. 11, the convex portion 58 of the fixed mold 32 is opened without engaging the movable recess 71. Resin is filled into the cavity 34 from the gate 77. After the completion of the filling process including the pressure adjusting step, when the clamping force is strengthened, the base 38 and the moving plate 46 of the fixed mold 32 are closed. Accordingly, the remaining resin in the cavity 34 is runner 76. 12, and as shown in FIG. 12, after the convex part 58 is engaged and the gate 77 is closed, resin of the cavity 34 is compressed.

In this molding, the product forming surface 91 of the sleeve 56 of the fixed mold 32 forms the upper surface of the stepped portion 108 of the roller holder 106 and the outer surface of the tapered portion 109, The protrusion piece 94 of the pin 93 of 32 forms the upper edge of the bridge part 110, forms the outer surface of the movable die 33, and the protrusion 96 of the movable die 33 is a roller holder. An inner surface of the 106 and a pair of side and bottom edges of the bridge portion 110 are formed.

The taper portion 109 of the roller holder 106 is inclined with respect to the mold opening and closing direction, and even though the taper portion 109 finally formed is thin, in the filling step and the pressure adjusting step, the fixed die 32 and The surfaces forming the tapered portion 109 in the movable die 33 are largely separated from each other. As a result, the resin smoothly flows into the portion formed of the tapered portion 109 in the cavity 34. There is nothing to cause a charging failure. In this process, in the compression step, the sleeve 56 compresses the tapered portion 109 so that the thin tapered portion 109 can be reliably formed without failure, and the bridge portion 110 is screwed. There is no such thing as to generate a sync mark on the outer surface of the tapered portion 109 in the combined portion. As a result, a stronger compression is applied to the tapered portion 109 inclined with respect to the mold opening and closing direction than the main body portion 107. In addition, the movable die 33 includes a protrusion 96 penetrating the inside of the tapered portion 109 and a slit portion 98 for lowering and enclosing the bridge portion 110. The fixed die 32 includes the base 38. ), A hole portion 92 to which the protrusion 96 is coupled, and a protrusion piece 94 to be coupled to the slit portion 98 are provided. The tapered portion 109 including the bridge portion 110 is provided. ) To compress the whole.

In addition, the present invention can be suitably used for molding various products such as mechanical pencils in advance. Moreover, various modifications can be made to the present invention without being limited to the above-described embodiments. For example, in the above-described embodiment, the case where an in-line screw injection molding machine is used is described as an example, but various things such as a plunger type can be used for the molding machine. In addition, although the clamping apparatus is a thing of the direct pressure type same as the above-mentioned embodiment, various things, such as a toggle type thing, can be employ | adopted. The driving source of the clamping device is not limited to the hydraulic cylinder, but may be an electric motor or the like. Moreover, the mold apparatus is also not limited to that of the above-described embodiment. For example, in addition to the spring, an injector or the like may be used as the spring means for pushing the movable body. Incidentally, in the above embodiment, injection molding of thermoplastic resin is employed as an example, but the present invention is an injection molding, injection molding powder coating method of ceramics used as a finder, or injection molding of thermosetting resin. Applicable to injection molding of various molding materials.

According to the present invention, it is possible to accurately control the pressure and the amount of the molding material to be filled in the cavity.

Claims (7)

And a first body and a second body that open and close to each other to form a cavity between each other when closing the mold, wherein the first body moves in the opening and closing direction of the gas and the first body and the second body described above. And a spring member for pushing the movable body in contact with and closing the second body which is possibly supported, and for pushing the movable body in the direction of the second body with respect to the base body. The volume of the cavity is changed by opening and closing the movable body and the gas in the closed state, and the gate from the material passage to the cavity is closed as the movable body and the gas are closed. Mold device, A material supply device for supplying a plasticized molding material to the material passage described above; A clamping device capable of opening and closing the first shaped body and the second shaped body of the mold apparatus and adjusting the clamping force; With the weak clamping force, the first body and the second body are closed, and the movable body and the second body are closed, while the movable body and the gas are open, by the material supply apparatus. Charge control means for supplying a molding material to the material passage of the mold apparatus and filling it into the cavity; During the filling by the filling control means, the moving body and the second mold body are displaced with respect to the gas by the balance between the pressure of the molding material in the mold apparatus and the clamping force, thereby forming the mold in the cavity. Regulating means for adjusting the pressure of the material, After the pressure adjustment by the pressure adjusting means, the clamping force is strengthened to close the gas and the moving body, and the molding material on the cavity side is returned to the material supply device side, and the above-mentioned point is closed when the gate is closed. Weighing control means for leaving a certain amount of molding material to the cavity side; And a compression control means for closing the gas and the movable body until they come into contact with each other after the weighing control by the metering control means, and compressing the molding material in the cavity. A first body and a second body of claim 1, further comprising: a first body and a second body that form a cavity for communicating with each other via a gate in the material passage when the mold is opened and closed. The first body includes a body, a movable body which contacts and closes the second body which is movably supported in the opening and closing direction of the first body and the second body, and the body of the body described above. Spring means for pushing in the direction of the second body with respect to the above-mentioned, and a convex part integrally provided with said body, The second body has a recess in which the convex portion of the first body is freely coupled, The above-mentioned cavity is formed by these convex portions and the concave portion, and the gate is closed by the convex portion coupled to the concave portion, and the material passage is the moving body and the second body and And a force formed by the spring means to push the movement 첵 is set to a force that maintains the closed state of the second body in response to the pressure of the molding material in the material passage. Injection Molding Mold Device 3. The injection molding die apparatus according to claim 2, wherein an overflow portion, which is blocked from the cavity when the convex portion is coupled to the concave portion, is held over approximately the entire circumference of the cavity. The said convex part slides freely through the said moving body freely, and surrounds the said convex part in this moving body, and forms the said overflow part in addition to the said material path and the said gate. Injection mold apparatus characterized in that the peripheral portion is formed. 3. The injection molding die apparatus according to claim 2, wherein the first mold is a fixed mold and the second mold is a movable mold. The injection molding die apparatus according to claim 2, wherein the spring means is a spring. And a first body and a second body that form cavities therebetween at the time of closing and closing each other, wherein the first body moves in the opening and closing direction of the body and the first body and the second body described above. And a spring means for pushing the movable body in contact with and closing the second body which is possibly supported, and pushing the movable body in the direction of the second body with respect to the body. The volume of the cavity is changed by opening and closing the movable body and the gas in the closed state, and the gate from the material passage to the cavity is closed as the movable body and the gas are closed. Mold device, A material supply device for supplying a plastic material in a plastic state to the material passage of the mold apparatus; Using a mold clamping device which opens and closes the first mold body and the second mold body of the above-mentioned mold apparatus and adjusts the clamping force, With the weak clamping force, the first body and the second body are closed, and the moving body and the second body are closed, while the moving body and the gas are open, the material passage is made by the material supply device. Supplying the molding material into the above-mentioned cavity, At this time, by the balance between the pressure of the molding material in the mold apparatus and the clamping force, the moving body and the second body with respect to the gas are displaced to adjust the pressure of the molding material in the cavity. , After stopping supply of the molding material from the material supply device, the clamping force is strengthened to close the gas and the moving body, In the meantime, first, the above-mentioned cavity-side molding material is returned to the above-described material supply apparatus, and a certain amount of the above-mentioned molding material is left on the cavity side at the time when the gate is closed, and then the above-mentioned gas and the above-mentioned An injection molding method, characterized in that the molding materials in the cavity are compressed by closing the moving bodies until they come into contact with each other.