JP2003117945A - Split molding method in injection molding machine and split mold assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that the strength of a welded part becomes low because the temperature of a resin in a mold lowers during filling in a method for filling the mold with materials at the same time from a plurality of gates to fuse the materials in an unsolidified state and strong mold clamping force is required in the case of a large-sized molded article because the mold is filled with a resin under high pressure at the time of injection and a mold clamping device becomes large-sized. SOLUTION: In an injection molding method for injecting a resin in cavities 15 in a split state from a plurality of branch runner 17, 18 and 19 and a plurality of gates 7 and 8 to integrally mold the same, the injection of the resin in one cavity among the cavities cut off by a plurality of on-off gate cores 11 from the branch runner and the resin is injected in the other cavity cut off by one of the on-off gate cores from the separate branch runner so as to delay timing from the previous injection timing and the space formed by the retreat of the on-off gate core is subsequently filled with the resin injected from the branch runner communicating with the space and the peripheries of the on-off gate cores are heated to hold the boundary parts of the resins to a molten state to fuse the resins before the fused resin is cooled and solidified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for injection molding into a mold such as an injection molding machine, and in particular, a weld having a low strength at the boundary of molding even when cavity division injection molding is performed at a different timing. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split molding method in which no part is generated and a mold device used for this molding method.

[0002]

2. Description of the Related Art For injection molding a long molded product, or for injecting a plurality of different color resins from a plurality of injection cylinders into a single mold to color the molded product with a plurality of colors. Adopts an injection molding method in which a resin passage is branched so that molten resin is filled into the mold cavity from a plurality of gates at the same time, and a conventional example thereof will be introduced below. The conventional example disclosed in Japanese Unexamined Patent Publication No. 8-20040 is to divide a cavity by providing an openable / closable shut-off core that shuts off a resin passage of a mold cavity, and each of the divided cavities has a molding material of a different color. The injection molding is performed at the same time, and before the solidification of the molten resin immediately before the completion of injection, the blocking core is pulled to release the blocking of the passage to complete the injection, and an integrally molded product with clear coloring boundaries. Can be obtained.

Further, in the injection molding method disclosed in Japanese Patent Application Laid-Open No. 7-246633, each resin passage for injecting two (plural) kinds of resins into a mold cavity and a gate for blocking each resin passage are provided. The mold is provided with a core to be inserted into the mold cavity. With the core inserted, a resin of the first type is injected to fill the space of the cavity, and the core is solidified to a certain degree at a timing. This is an injection molding method in which the gate for the second type of resin is opened at the same time as the removal, and the second type of resin is injected into the space after the core is removed.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
When injection molding a long molded product, the method of injecting the molding material into the divided cavities from multiple runner gates at the same time and opening the resin passage while the resin is not solidified to fuse the molding material is Since the resin temperature in the mold decreases during filling, the weld strength between the resin and the resin weakens, and since the molten resin is filled at a high pressure during injection, internal pressure is applied to the entire mold. In the case of a molded product having a large projected area of the mold cavity, a strong mold clamping force is required for the mold, and the mold clamping device inevitably becomes large. The present invention provides an injection molding method and a metal mold capable of maintaining the adhesive strength of a weld portion between resins under the injection conditions as described above and not requiring a large mold clamping force with respect to a mold. It is an object to provide a mold device.

[0005]

In order to solve the above problems, the present invention aims to solve the problems by means having the characteristics described in the following items. (1) In an injection molding method in which molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold and integrally molded, in a mold cavity blocked by a plurality of open / close gate cores. Injection from a branch runner that communicates with one of the cavities is performed, and the timing is delayed from the injection from another branch runner that communicates with another cavity that is blocked by one of the open / close gate cores. After injection, the space formed by the retreat of the opening / closing gate core is injected from the branch runner communicating with it to fill the molten resin,
A divided injection molding method, characterized in that the periphery of the opening / closing gate core is heated to fuse and fuse the boundary portions of the sequentially injected resin in a molten state, followed by cooling and solidification. (2) In an injection molding method in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a mold runner and integrally molded, a mold cavity that is cut in half by an open / close gate core is used. After performing the primary injection from the first branch runner to one side and performing the secondary injection from the second branch runner to the other half of the cavity with a timing later than the primary injection, the opening / closing gate core is opened. A third injection is performed from the third branch runner to fill the molten resin, and the periphery of the opening / closing gate core is heated so that the boundary portion between the primary, secondary and tertiary injection resins is melted. A split injection molding method in which the materials are kept and fused and then cooled and solidified. (3) In the split injection molding method according to the above (1) and (2), after sequentially injecting the resin, the boundary portion of the resin is melted and fused, and then the resin boundary portion is partially added by the opening / closing gate core. A split injection molding method characterized by applying pressure.

(4) In a die unit of an injection molding machine, in which a molten resin is dividedly injected into a die cavity from a plurality of branch runners and gates branched from a runner of the die and integrally molded, the die cavity is branched. At least one opening / closing gate core provided with an actuator for opening / closing operation so as to divide the cavity at the same time as closing the runner, a heater provided at the tip of the opening / closing gate core, and the opening / closing gate core of the mold cavity. A plurality of branch runners leading to each of the cavities, and a controller for controlling the operation of the opening / closing gate core, the gate operation of the runner, and the heating timing of the heater of the opening / closing gate core. ) To (3), the mold device is characterized in that it is divided and injection-molded. (5) In an injection molding method in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a mold runner and integrally molded, the mold is blocked by at least one opening / closing gate core. Injecting into one of the cavities, delaying the timing to release the blocking of the mold cavity by the gate core, or at the same time as before releasing the blocking, the cavity divided by the opening / closing gate core and the injection is performed. It is characterized by performing injection into other adjacent cavities and heating the periphery of the boundary of the injection resin that has been performed sequentially, keeping the boundary of the injection resin in a molten state and fusing it, and then cooling and solidifying. Injection molding method.

(6) In an injection molding method in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a mold runner and integrally molded, a metal that is cut in half by an opening / closing gate core. The primary injection is performed to one side of the mold cavity, the timing is delayed to release the blocking of the mold cavity by the gate core, and at the same time the secondary injection is performed to the remaining half of the cavity to perform the primary injection and the first injection. An injection molding method in which the boundary portion between the primary and secondary injection resins is fused in a molten state by fusing the periphery of the boundary of the secondary injection, followed by cooling and solidification.

(7) In the split injection molding method described in the above (5) and (6), after the resin is sequentially injected, the boundary portion of the resin is melted while being fused, and then the opening / closing gate core is used to partially cover the resin boundary portion. The method of divided injection molding, characterized in that the pressure is applied selectively. (8) In a mold device of an injection molding machine that divides and injections molten resin into a mold cavity from a plurality of branch runners and gates branched from a mold runner and integrally molds the mold cavity, the mold cavity is divided and cut off. At least one opening / closing gate core having an actuator for opening / closing operation, and a heater provided at the tip of the opening / closing gate core, respectively.
A gate provided in each branch runner leading to each of the mold cavities divided by the opening / closing gate core; and a control device for controlling the operation of the opening / closing gate core, the gate operation of the branch runner, and the heating timing of the heater of the opening / closing gate core. And a molding apparatus, which is injection molded by the method according to any one of (5) to (7) above. (9) In an injection molding method in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a mold runner and integrally molded, the center part and the outer part are blocked from the mold cavity. A pair of open / close gate cores that are divided into three parts are operated to the closed side, the primary injection is performed to the central mold cavity through the central branch runner, and the opening / closing gate core is operated to the open side with a delayed timing after the primary injection. At the same time, a second injection is performed from a pair of outer branch runners to inject to both outside parts of the mold cavity for molding, and the periphery of the boundary between the primary injection resin and the secondary injection resin is injected. The injection molding method is characterized in that the first and second injection resins are heated and heated to fuse the boundary portions of the injection resin while being melted, and then cooled and solidified.

(10) In the split injection molding method described in (9) above, after the boundary portions of the sequentially injected resin are fused while being fused, the resin boundary portions are partially pressed by the open / close gate core. A divided injection molding method characterized by the above.

(11) In a mold apparatus of an injection molding machine, in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold and integrally molded, the center of the mold cavity is used. A pair of open / close gate cores equipped with an actuator that shuts off the outer and outer parts, a heater provided at the tip of the open / close gate core, a gate provided in a central branch runner leading to the central portion of the mold cavity, and a mold A gate provided to each of a pair of branch runners leading to both outer side portions of the cavity, and a controller for controlling the operation of the gate core, the operation of the gate of each branch runner, and the heating timing of the heater of the gate core. And a molding apparatus for an injection molding machine, which is injection-molded by the method described in (9) and (10) above.

(12) A plurality of injection units and a plurality of runners are provided for the same mold cavity, and the mold cavity is divided with the separable open / close gate core having the mold cavity provided in the middle part on the closing side. In the injection molding method in which different or different colored molten resins are injected from a plurality of injection units and the gate core is opened and molded integrally at the end of the injection process, to one side of the mold cavity that is cut in half by the opening / closing gate core. Injection from the first injection unit, the timing is delayed to release the block of the mold cavity by the gate core, and then the second half of the cavity and the gap left by the gate core are injection-filled and molded from the second injection unit. By heating the periphery of the boundary between the primary injection and the secondary injection, the boundary between the primary and secondary injection resins is melted. An injection molding method, characterized in that after being held and fused, it is cooled and solidified.

(13) In the split injection molding method according to the above (12), after sequentially injecting resin, the boundary portion of the resin is melted while being fused, and then the opening / closing gate core partially presses the resin boundary portion. A divided injection molding method characterized by the above.

(14) A plurality of injection units and a plurality of runners are provided for the same mold cavity, and the mold cavity is divided with the opening / closing gate core capable of dividing the middle part of the mold cavity on the closed side. In the mold device of the injection molding machine, in which different or different colored molten resins are injected from the injection unit, and the gate core is opened and molded integrally at the end of the injection process, the mold cavity is divided into two parts at the center to open and close. An opening / closing gate core provided with an actuator for operation, a heater provided at the tip of the opening / closing gate core, a runner that directly communicates from each injection unit to the mold cavity, injection timing of the injection unit, and operation of the gate core. And a control device for controlling the heating timing of the heater of the gate core.
A mold apparatus, which is injection-molded by the method described in 3). (15) In the above (4), (8), (11), and (14), the molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from the mold runner and integrally molded. In the mold device, a high-frequency current induction heater is used as a means for heating the mold surface around the gate core that blocks the mold cavity, and the temperature detection sensor and the temperature control device control the resin temperature and the heating timing. It would be a better option.

[0014]

DETAILED DESCRIPTION OF THE INVENTION

[First Embodiment] In the split molding method according to the first embodiment of the present invention, a mold cavity is divided into two parts by a gate core, and a runner branched from a single injection cylinder gives a timing difference to perform the separate molding. FIG. 1- (II), FIG. 1- (II), and FIG. 1- (II) are sectional views of the molding die device.
I) and FIG. 5 will be described with reference to the timing chart of the injection process.

In the figure, reference numeral 1 is an injection cylinder, in which the injection screw 2 rotates. Molten resin 10
Is injected into the mold cavity 15 through the runner 16. 5 is a fixed mold attached to the fixed die plate 3,
A movable die 6 is attached to the movable die plate 4. Clamping pressure is applied to the molds 5 and 6 by the fixed die plate 3 and the movable die plate 4. Runner 16
Branch to runners 17, 18 and 19 and branch runner 1
7 is opened and closed by a gate (valve) A7, and a branch runner 1
8 is opened and closed by a gate (valve) B8. Reference numeral 11 is a gate core that slides in the movable mold 6.
Is an actuator 1 attached to a movable die plate 4.
3, the resin passage of the cavity 15 is opened and closed. Reference numeral 12 is a heater provided at the tip of the gate core 11. The heater 12 heats and cools the molten resin 10 in the cavity 15 at an appropriate timing. Reference numeral 43 is a pressure detection sensor for detecting the mold internal pressure. Reference numeral 44 denotes a temperature sensor that detects the tip temperature of the heater 12. The tip temperature of the heater 12 is controlled by a control device (not shown) that receives the detection signal of the temperature sensor 44, and the heating timing of the heater 12 is also controlled. It is controlled by a control device (not shown).

A method of injecting and filling the mold with the molten resin 10 will be described with reference to the timing of the injection process shown in FIGS. The injection screw 2 rotates in the injection cylinder 1 to plasticize and melt while feeding the resin material, and a fixed amount of the molten resin 10 is accumulated at the tip of the injection screw 2 in the injection cylinder 1 and then the injection screw 2 The rotation is stopped, and the molten resin 10 is advanced and injected into the mold cavity 15 through the runner 16. At this time, the gate core 11 closes the resin passage in the center of the cavity 15 to close the gate (valve).
With B8 closed, the gate (valve) A7 is opened, and the injection screw 2 performs the primary injection of about half of the total injection amount (FIG. 1- (I)).

Then, the gate (valve) A7 is closed, the gate (valve) B8 is opened, and the second half injection is performed in the remaining half cavity (FIG. 1- (II)), and then the mold internal pressure is maintained for a while. The gate (valve) B8 is closed, the gate core 11 is pulled out, the passage of the cavity 15 is opened, and at the same time, the central branch runner 19 is opened to perform the third injection (FIG. 1- (III)). At this time earlier than this, the heater 12 is caused to generate heat to raise the temperature of the gate core 11 to raise the temperature of the resin which has started to solidify, and the first, second, third
The boundary of the resin for the next injection is heated so that the resin is fused while being kept in a molten state, so that the adhesion of the weld between the resins is improved and the adhesion strength is improved. Then, stop the heat generation of the heater 12,
(Cooling) The temperature is controlled to be the same as that of the mold 6, and the pressure of the resin is maintained and the process proceeds to the cooling process.

FIG. 5 (1) shows the timing of injection and pressure holding when the molten resin is injected and filled from one runner gate at a time in a normal injection molding machine. FIG. 5- (2) shows the timing of injection and pressure holding when the molten resin is injected and filled simultaneously from the two runner gates. If the molds 5 and 6 shown in FIG. 1 are used, the gate A7 and the gate B8 are simultaneously opened while the gate core 11 is pulled to keep the resin passage of the cavity 15 open, and the molten resin 10 is placed in the cavity 15. Injection fill. FIG. 5- (3) shows the timing of injection and pressure holding when the molten resin is injected and filled with the timing shifted from the two runner gates. If the mold shown in FIG. 1 is used, the gate core 11 is extruded and the cavity 1
The resin passage of 5 is closed, the gates A7 and B8 are opened at a shifted timing, and at the same time, the gate core 11 is opened and the molten resin 10 is sequentially injected and filled into the cavity 15.

FIG. 5 (4) shows that when the molten resin is injected and filled with the timing shifted from the two runner gates, it is held for a while after the first injection, the gate core is opened, and the second core is opened.
The timing of injection and pressure holding at the time of the next injection is shown. If the mold shown in FIG. 1 is used, the gate core 11 is pushed out to close the resin passage of the cavity 15,
Open the gate A7 and put molten resin 1 in half of the cavity 15.
After injecting and filling 0, the gate A7 was closed and held for a while, and it was confirmed that the mold internal pressure detection signal of the mold internal pressure sensor 43 became low, the gate core 11 was opened, the gate B8 was opened, and the other half of the cavity 15 was opened. Then, the molten resin 10 is injected and filled. The mold apparatus according to the first embodiment is similar to that shown in FIG.
The injection filling method of (2) to FIG. 5- (4) is possible, and at the time of this injection filling, the heater 12 attached to the gate core 11 heats and merges the merging portion of the resin flow to reduce the decrease in the strength of the weld. I am trying to do it.

FIG. 6 shows a flow state of molten resin (second figure from the top) when a long molded product (for example, a bumper of an automobile) is subjected to normal one-stage injection molding, and the injection timing is shifted to the two-stage injection. Shows the flow state of the molten resin (part 1 upper diagram) and the distribution state of the mold internal pressure during injection and filling (bottom diagram) when partial connection molding is performed by The internal pressure is shown, and the thick solid line shows the internal pressure of the mold on one side during the partial connection molding. The hatched portion of the vertical line in FIG. 6 shows a change state of the mold pressure due to the frictional resistance of the molten resin during the injection filling in the normal one-step injection molding.

In the normal one-step injection molding, since the distance from the cavity inlet of the molten resin to both ends is long, friction between the passage in the cavity and the molten resin is large, and when the flow velocity of the molten resin is the same, Since the pressure loss during injection molding is larger than that during partial connection molding, and the pressing force for injection also increases, it is unavoidable to slow down the injection speed, but if the injection speed slows, The molten resin easily cools in the middle of the resin passage, and a larger injection pressure is required for the resin to reach the terminals. In addition, if the mold internal pressure increases in this way, the mold clamping force that holds down the surface of the mold cavity also inevitably increases.

As described above, if the partial connection molding is performed, the internal pressure of the mold becomes low, so that the mold clamping force for pressing the entire surface of the cavity is small. In other words, if the mold internal pressure is the same, the injection speed can be increased. Further, as shown in FIG. 5- (4), the resin passage of the cavity 15 is divided by the gate core 11, and the molten resin 10 is injection-filled by shifting the timing to each half of the cavity 15, and the resin on one side is cooled and the mold is cooled. If the molten resin 10 is injected and filled into the cavity 15 for the latter half when the internal pressure is reduced, the mold clamping force can be further halved.
In addition, the strength of the molded product can be improved even with a low mold clamping force by partially pressurizing the resin confluence portion by the gate core 11 to cause the resin to flow. In this embodiment, the case where one gate core is used has been described.
It is also possible to perform molding using a plurality of gate cores.

[0023]

[Second Embodiment] As in the first embodiment, the split molding method according to the second embodiment of the present invention divides the mold cavity into two parts by a gate core and branches from a single injection cylinder. FIG. 2 (I) is a cross-sectional view of a molding die device, in which a runner is used to perform differential molding at different timings.
This will be described with reference to FIGS. 2- (II) and FIG. 5 showing the timing of the injection process. The difference from the first embodiment is that
The central branch runner 1 provided in the first embodiment
9 is omitted. Therefore, the structure is the same as that of the first embodiment except for the fixed side mold having the branch runner, and the description of the same structure is omitted.

The molten resin 10 is injected into the mold cavity 15 through the runner 22. At this time, the gate core 1
1 is a state in which the resin passage in the center of the cavity 15 is closed and the gate (valve) B 28 is closed, and the gate (valve) A is
27, open the injection screw 2 to about half of the total injection volume
Next injection is performed (FIG. 2- (I)). Next, the gate (valve) A27 is closed and held for a while, and the mold pressure sensor 43
After confirming that the in-mold pressure detection signal has decreased, the gate core 11 is pulled out, the gate (valve) B28 is opened, and the second injection is performed into the remaining half of the cavity. At this time earlier, the heater 12 is caused to generate heat to raise the temperature of the gate core 11 to raise the temperature of the resin which has started to solidify to heat the boundary between the resins of the primary injection and the secondary injection, thereby making a molten state. By keeping them to fuse together, the adhesion of the weld between the resins is improved and the adhesive strength is improved. Also, the gate core 11
Further strength improvement can be achieved by partially pressurizing the resin boundary portion by using to cause the resin to flow. Then the heater 1
The heat generation of No. 2 is stopped, (cooling) is performed, the temperature is controlled to the same as that of the mold 6, and the pressure of the resin is maintained and the process proceeds to the cooling process.

Like the mold of the first embodiment, the mold apparatus of the second embodiment also has the injection and pressure holding timings shown in FIGS. 5- (2) to 5- (4). The molten resin can be injected and filled simultaneously or sequentially from two runner gates. Therefore, even during this injection filling, the gate core 1
(1) The joining portion of the resin flow is heated and fused by the attached heater 12 to reduce the decrease in the strength of the weld, and a long molded product is partially coupled by two-stage injection by shifting the injection timing. As a result, the same effect as the first embodiment can be obtained. In this embodiment, the case where one gate core is used has been described, but it is also possible to perform molding using a plurality of gate cores.

[0026]

[Third Embodiment] In the split molding method according to the third embodiment of the present invention, a mold cavity is divided into three parts by a pair of gate cores, and a runner branched from a single injection cylinder is used to make a difference in timing. This is divided molding, and will be described with reference to the cross-sectional views of the molding die device, FIG. 3- (I), and FIG. 3- (II). The difference from the first embodiment is that the mold cavity is divided into three parts by a pair of gate cores, and injection filling into the cavities in the center is delayed and injection filling is performed into the cavities on both sides. Except for this configuration, the configuration is the same as that of the first embodiment, and the description of the same configuration is omitted.

Reference numeral 35 is a fixed die attached to the fixed die plate 3, and 36 is a movable die attached to the movable die plate 34. The runner 32 is a branch runner 33, 39,
41, and the branch runner 33 is a gate (valve) C4.
Open and close from 0, branch runner 39 gate (valve) A3
7, the branch runner 41 is a gate (valve) B
It opens and closes by 38. 11A and 11B are gate cores that slide in the movable mold 36.
B opens and closes the resin passage of the cavity 31 by the actuators 13A and 13B attached to the movable die plate 34. Reference numerals 12A and 12B denote heaters provided at the respective tips of the gate cores 11A and 11B. The heaters 12A and 12B heat and cool the molten resin 10 in the cavity 31 at appropriate timings. Reference numeral 43 is a pressure detection sensor for detecting the mold internal pressure. Further, 44A and 44B are temperature sensors that detect the tip temperatures of the heaters 12A and 12B, and the tip temperatures of the heaters 12A and 12B are the temperature sensors 4.
The control device (not shown) that receives the detection signals of 4A and 44B controls the heating timing of the heaters 12A and 12B.

The molten resin 10 is injected into the mold cavity 31 through the runner 32. At this time, the gate core 1
In 1A and 11B, the resin passages on both sides of the center of the cavity 31 are closed, and a gate (valve) A37 and a gate (valve) B3 are provided.
8, the gate (valve) C40 is opened in the closed state, and the injection screw 2 performs the primary injection of about 1/3 of the total injection amount (FIG. 3- (I)). Next, the gate (valve) C40 is closed and held for a while, and it is confirmed that the mold internal pressure detection signal of the mold internal pressure sensor 43 becomes low, and the gate cores 11A, 1
1B is pulled out, the gate (valve) A37 and the gate (valve) B38 are simultaneously opened, and the secondary injection is performed into the remaining cavity. Heater 12A, 1
2B is heated to raise the temperature of the gate cores 11A and 11B to raise the temperature of the resin which has started to solidify and heat the boundary between the resins of the primary and secondary injections so that the molten state is maintained and fused. And improve the adhesion of the weld between the resin,
Improves adhesive strength. In addition, the gate cores 11A and 11A
By using B to partially press the resin boundary portion to flow the resin, the strength can be further improved. Then, the heat generation of the heaters 12A and 12B is stopped, and (cooling) the temperature is controlled to be the same as that of the mold 36, and the process of holding the pressure of the resin and cooling is performed.

Similarly to the molds of the first and second embodiments, the mold device of the third embodiment is also shown in FIGS.
At the timing of injection and pressure retention shown in (4), the molten resin can be injected and filled simultaneously or sequentially from the three runner gates. Therefore, even during this injection and filling, the heaters 12A and 12B attached to the gate cores 11A and 11B heat the fusion portions of the resin flows to fuse them together so as to reduce the decrease in the strength of the weld. By performing the partial connection molding by the two-stage injection while shifting the timing of 1, the same effect as that of the first embodiment can be obtained.

[0030]

[Fourth Embodiment] In the split molding method according to the fourth embodiment of the present invention, a mold cavity is divided into two parts by a gate core, and a pair of injection cylinders are separately formed by different runner timings. This is described with reference to the sectional views of the molding die device, FIG. 4- (I), and FIG. 4- (II). The difference from the first embodiment is that two injection cylinders are installed, and the injection cylinders perform injection filling at the same time or at different timings, and the branching of the central portion provided in the first embodiment is performed. The runner 19 is unnecessary. Except for this configuration, the configuration is almost the same as that of the first embodiment, so description of the same configuration will be omitted.

Reference numeral 52 is a fixed mold attached to the fixed die plate 51, and 6 is a movable mold attached to the movable die plate 4. Two runners 53, 54 of fixed mold 52
Nozzles of two injection cylinders 1A and 1B are crimped to the entrances of the two. The runners 53, 54 are connected to a single cavity 55. The gate core 11 is fitted into a through hole formed in the center of the movable mold 6, and the gate core 11 is
Actuator 13 mounted on movable die plate 4
Thus, the resin passage at the center of the cavity 55 is reciprocally slid so as to block the passage. 12 is the gate core 1
It is a heater provided at the tip of 1. Reference numeral 43 is a pressure detection sensor for detecting the mold internal pressure, 44 is a temperature sensor for detecting the tip temperature of the heater 12, and the temperature of the heater 12 is controlled by a control device (not shown) that receives the detection signal of the temperature sensor 44 to heat the heater 12. The heating timing of the container 12 is also controlled by a controller (not shown).

The two injection cylinders 1A and 1B can respectively inject the same kind, different kinds or different colors of resin materials. In FIG. 4, the injection cylinder 1A is a resin A50,
The injection cylinder 1B is adapted to inject the resin B50. Further, the injection screws 2A and 2B of the injection cylinders 1A and 1B are separately driven for injection. The gate core 11 is projected to close the resin passage in the center of the cavity 55, and first, the injection screw 2A is driven to perform the primary injection of about half of the total injection amount (FIG. 4- (I)).

After keeping the state as it is for a while, after the mold pressure sensor 43 confirms that the mold pressure of the resin A50 has become low, the gate core 11 is pulled to open the passage of the cavity 55, and the injection screw 2B is driven for injection. Then, the second half of the total injection amount is subjected to the second injection (FIG. 4- (II)). At this time earlier, the heater 12 is caused to generate heat to raise the temperature of the gate core 11 to raise the temperature of the resin that has started to solidify to heat the boundary between the resins of the primary and secondary injections, and the molten state By keeping them to fuse together, the adhesion of the weld between the resins is improved and the adhesive strength is improved. Further, the strength of the resin can be further improved by partially pressurizing the resin boundary portion using the gate core 11 to cause the resin to flow. Then, the heat generation of the heater 12 is stopped, and the temperature is controlled (cooled) to the same temperature as that of the mold 6, and the process proceeds to the process of maintaining the pressure of the resin and cooling.

Like the molds of the first and second embodiments, the mold device of the fourth embodiment is also shown in FIGS.
At the timing of injection and pressure holding shown in (4), the molten resin can be injected and filled from the two injection cylinders 1A and 1B simultaneously or sequentially. Therefore, even at the time of this injection filling, the heater 12 attached to the gate core 11 heats and merges the joining portion of the resin flow to reduce the decrease in the strength of the weld, and the injection timing of a long molded product is shifted. By performing partial connection molding by two-stage injection, the same effect as that of the first embodiment can be obtained. In addition, this mold device can also perform connection molding of connection molded products of different materials and connection molded products of different color materials.

[0035]

INDUSTRIAL APPLICABILITY According to the present invention, in a mold device of an injection molding machine, a gate core for dividing a mold cavity is provided, a plurality of branch passages and a gate valve are provided on a runner of the mold, and the mold cavity is divided. When the molten resin is injected into the mold cavities that are opened by opening the gate at different timings, the gate core that divides the mold cavities is opened and molded integrally before the next injection or at the same time. Is heated and fused by a heater provided at the tip of the gate core, which has the effect of reducing the decrease in the strength of the weld at the resin merging portion, and further effects can be expected if the resin merging portion is pressurized. . Moreover, since the internal pressure of the mold is reduced by performing the partial connection molding, the mold clamping force for pressing the entire surface of the cavity can be small. Therefore, the pressing mechanism of the mold clamping device can be downsized and the manufacturing cost can be reduced. It will be possible. In other words, if the in-mold pressure is the same, the injection speed can be increased and the molding capacity can be improved. Furthermore, if the cavity is divided by the gate core and the divided cavities are staggered for injection filling with molten resin, the mold clamping force can be further reduced, especially when injection-filling a long molded product. It is very cost effective (claims 1-8).

In addition to the above-mentioned effects, the one obtained by dividing the mold cavity into three and adopting the above-mentioned division molding method is suitable for a mold of a long molded product (claims 9, 10, 11).
The method and apparatus for supplying the molten resin by using a plurality of injection cylinders and performing the above-described split molding can integrally mold different-type and different-color resins, and can achieve the same effect as described above. , 13, 14). If an induction heating method is used for the heater, rapid heating is easy, so it is suitable as a heating method for the tip of the gate core of this mold device.
5).

[Brief description of drawings]

FIG. 1 is a sectional view (I), (II), (II) of a molding die apparatus for explaining a split molding method according to a first embodiment of the present invention.
I).

FIG. 2 is cross-sectional views (I) and (II) of a molding die apparatus for explaining a split molding method according to a second embodiment of the present invention.

FIG. 3 is sectional views (I) and (II) of a molding die device for explaining a split molding method according to a third embodiment of the present invention.

FIG. 4 is sectional views (I) and (II) of a molding die device for explaining a split molding method according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing timings of an injection process in various injection filling methods.

FIG. 6 is a diagram comparing an internal mold pressure distribution state in a normal single runner injection filling method and a mold injection pressure distribution state in split injection filling molding.

[Explanation of symbols]

1 Injection Cylinder 2 Injection Screws 5, 25, 52 Fixed Mold 6 Movable Movable 7, 27 Gate A 8, 28 Gate B 10 Molten Resin 11 Gate Core 12 Heater 15, 31 Cavity 16, 22, 32, 53, 54 Runner 17 , 18, 19, 23, 24, 39, 41, branch runner 50 molten resin A 60 molten resin B

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Fumio Inayoshi             1 Takamichi, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi               Mitsubishi Heavy Industries, Ltd., Industrial Equipment Division (72) Inventor Yukio Tamura             60, Kyutansho, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi             1 Churyo Engineering Co., Ltd. F-term (reference) 4F202 AK01 AM36 AP02 AR06 AR11                       CA11 CB22 CK02 CK06 CK07                       CK17 CK42 CK52 CN01 CN05                 4F206 AK01 AM36 AP024 AR064                       AR11 JA07 JB22 JL02 JN12                       JN13 JN14 JN22 JQ81 JT01

Claims (15)

[Claims] 1. An injection molding method in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold to integrally mold the mold, and the mold is interrupted by a plurality of open / close gate cores. Injection from a branch runner that communicates with one of the cavities and from another branch runner that communicates with another cavity that is blocked by one of the open / close gate cores. After the injection is delayed, the space created by the retraction of the opening / closing gate core,
Injection is performed from a branch runner that communicates with this to fill the molten resin, and the periphery of the opening / closing gate core is heated so that the boundary portions of the sequentially injected resin are held in a molten state and fused, and then cooled and solidified. A divided injection molding method characterized by the above. 2. An injection molding method in which a molten resin is separately injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold to integrally mold the mold, and the mold is cut in half by an opening / closing gate core. The primary injection is performed from the first branch runner to one side of the cavity, and the secondary injection is performed from the second branch runner to the other half of the cavity with a timing later than the primary injection, and then the opening / closing gate core Is opened and the third injection is performed from the third branch runner to fill the molten resin, and the periphery of the opening / closing gate core is heated to melt the boundary portion of the primary, secondary and tertiary injection resins. A divided injection molding method, characterized in that after fusion is performed while maintaining the state, the material is cooled and solidified. 3. The split injection molding method according to claim 1, wherein after sequentially injecting the resin, the boundary portions of the resin are melted while being fused, and then the opening / closing gate core partially presses the resin boundary portion. A divided injection molding method characterized by the above. 4. A mold runner of a mold cavity, comprising: a plurality of branch runners branched from a runner of a mold and a gate of a mold cavity of an injection molding machine for separately injecting a molten resin into a mold cavity for integral molding. At least one opening / closing gate core equipped with an actuator for opening / closing operation so as to divide the cavity at the same time, a heater provided at the tip of the opening / closing gate core, and the opening / closing gate core of the mold cavity. The control device for controlling the timing of the operation of the opening / closing gate core, the operation of the gate of the runner, and the heating of the heater of the opening / closing gate core, the gates being provided in each of the plurality of branch runners leading to each of the cavities. A mold apparatus characterized in that it is divided and injection-molded by the method of 3. 5. In an injection molding method in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold and integrally molded, at least one opening / closing gate core is cut off. Injection is performed into one of the mold cavities, and the timing is delayed to release the blocking of the mold cavity by the gate core, or at the same time as before the blocking is released, the injection is divided by the opening / closing gate core. After injecting into another cavity adjacent to the cavity and heating the periphery of the boundary of the injection resin performed sequentially, after melting the boundary portion of the injection resin in a molten state, after fusion,
An injection molding method characterized by being cooled and solidified. 6. An injection molding method in which a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold to integrally mold the mold, and the mold is cut in half by an opening / closing gate core. The first injection is performed to one side of the cavity, the timing is delayed to release the block of the mold cavity by the gate core, and at the same time the second injection is performed to the remaining half of the cavity to perform the first injection and the second injection. An injection molding method, characterized in that by heating the periphery of the boundary of the next injection, the boundary parts of the primary and secondary injection resins are kept in a molten state and fused, and then cooled and solidified. . 7. The split injection molding method according to claim 5, wherein after sequentially injecting the resin, the boundary portions of the resin are fused while being fused, and then the opening / closing gate core partially presses the resin boundary portion. A divided injection molding method characterized by the above. 8. A mold apparatus of an injection molding machine, wherein a plurality of branch runners branched from a runner of a mold and a gate divide and inject a molten resin into a mold cavity to integrally mold the divided mold cavity. At least one opening / closing gate core equipped with an actuator for opening / closing operation, a heater provided at the tip of the opening / closing gate core, and a branch runner communicating with each of the mold cavities divided by the opening / closing gate core. The injection molding is performed by the method according to claim 5, which is configured by a gate provided respectively and a control device for controlling the timing of the operation of the opening / closing gate core, the gate operation of the branch runner, and the heating of the heater of the opening / closing gate core. A mold apparatus characterized by the above. 9. An injection molding method in which a molten resin is separately injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold to integrally mold the resin, and a central portion and an outer portion are formed in the mold cavity. A pair of open / close gate cores that are cut off and divided into three parts are operated to the close side, the primary injection is performed to the central mold cavity through the central branch runner, and the timing is delayed after the primary injection to open and close the open / close gate core. To the second at the same time it operates from a pair of outer branch runners.
Next injection is performed to both outside parts of the mold cavity to perform molding, and the periphery of the boundary between the primary injection resin and the secondary injection resin is heated to produce the primary and secondary injection. The injection molding method is characterized in that the boundary portion of the injection resin is melted while being kept in a molten state, and then cooled and solidified. 10. The split injection molding method according to claim 9, wherein the resin boundary portions that have been sequentially injected are melted while being held in a molten state, and then the opening / closing gate core partially presses the resin boundary portion. Characteristic split injection molding method. 11. A mold device of an injection molding machine, wherein a molten resin is dividedly injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold and integrally molded, in a central part of the mold cavity. And a pair of open / close gate cores equipped with an actuator that shuts off the outer part, a heater provided at the tip of the open / close gate core, a gate provided in a central branch runner leading to the central part of the mold cavity, and a mold cavity A gate provided in each of a pair of branch runners leading to both outer parts of the, and a controller for controlling the operation of the gate core, the operation of the gate of each branch runner, and the heating timing of the heater of the gate core. A mold apparatus for an injection molding machine, which is injection-molded by the method according to claim 9. 12. A mold cavity is divided into a plurality of injection units and a plurality of runners for the same mold cavity, and a separable open / close gate core provided in the middle of the mold cavity is closed. In the injection molding method of injecting different or different colored molten resins from a plurality of injection units and opening the gate core at the end of the injection process to integrally mold the resin, one side of the mold cavity cut in half by the opening / closing gate core Injection is performed from the first injection unit, the timing is delayed to release the blocking of the mold cavity by the gate core, and then the second half of the cavity and the gap left by the gate core are injection-filled and molded from the second injection unit, By heating the periphery of the boundary between the primary injection and the secondary injection, the boundary between the primary and secondary injection resins is kept in a molten state. An injection molding method characterized in that after fusion, they are cooled and solidified. 13. The split injection molding method according to claim 12, wherein after the resin is sequentially injected, a boundary portion of the resin is melted while being fused, and then the opening / closing gate core partially pressurizes the resin boundary portion. Characteristic split injection molding method. 14. A plurality of injection units and a plurality of runners are provided for the same mold cavity, and the mold cavity is divided with the opening / closing gate core capable of dividing the middle part of the mold cavity being closed to divide the mold cavity. In a mold device of an injection molding machine in which different or different colored molten resins are injected from an injection unit and the gate core is opened and integrally molded at the end of the injection process, the mold cavity is divided into two at the center to open and close. Opening / closing gate core equipped with an actuator for heating, a heater provided at the tip of the opening / closing gate core, a runner that directly communicates from each injection unit to the mold cavity, injection timing of the injection unit, operation of the gate core, and gate core And a control device for controlling the timing of heating of the heating device, and the injection is performed by the method according to claim 12 or 13. Mold device characterized by molding. 15. The mold apparatus according to claim 4, 8, 11 or 14, wherein molten resin is separately injected into a mold cavity from a plurality of branch runners and gates branched from a runner of the mold to integrally mold the resin. A high-frequency current induction heater is used as a means for heating the mold surface around the gate core that shuts off the mold cavity, and the resin temperature and the heating timing are controlled by a temperature detection sensor and a temperature control device. Injection molding machine.