JP3629996B2 - Injection molding method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection molding method and apparatus, and more particularly to an injection molding method and apparatus suitable for molding an insert molded product, for example, a small rotor with a built-in magnet.
[0002]
[Prior art]
Generally, a small rotor for a watch is obtained as an injection molded product. The process of the injection method of this type of insert product is as follows. First, a magnet material is loaded into a lower mold cavity in a mold opening with respect to a mold in which a plurality of cavities are formed by a lower mold and an upper mold. Thereafter, the mold is clamped and the resin is injected and injected. After a predetermined time, the mold is opened and the product is extruded and taken out. Since the runner resin remains in one mold, the runner is removed from the mold and the next injection process is started. Therefore, a plurality of molded products are obtained at a time by one injection operation, and a multi-cavity of 6 or more is common.
[0003]
[Problems to be solved by the invention]
However, in the conventional injection molding method, since it is intended to increase the work efficiency by taking a large number of pieces at a time, the size of the apparatus is unavoidable, and the mold clamping load increases as the number of picks increases. In other words, there was a problem that a clamping force of about 15 tons was required for 6 pieces. In addition, as described above, until the product is taken out, a series of processes such as loading of the insert part into the cavity, resin injection into the mold-clamped cavity, product taking out, and runner removal must be performed. This cycle time is currently required to be 10 to 11 seconds, and since it takes a little less than 2 seconds to obtain one product, it is desired to further shorten this cycle time.
[0004]
A rotary type injection molding machine is known as a device for speeding up injection work (Japanese Patent Laid-Open No. 8-281696). This corresponds to two or more lower molds corresponding to one upper mold, and is configured such that a plurality of lower molds are arranged around the rotary table, and mold clamping injection on one lower mold side In accordance with the work, an injection product is taken out on the other lower mold side to shorten the cycle time. However, even with this method, there is a limit to shortening the cycle time.
[0005]
An object of the present invention is to provide an injection molding method and apparatus capable of significantly reducing the molding cycle time of an insert molded product, paying attention to the above-mentioned conventional problems.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an injection molding method according to the present invention circulates a lower mold located simultaneously on a plurality of stages including an injection stage, and alternately moves a mold clamping position and a retracted position on the injection stage. Molding is performed by repeatedly performing mold clamping injection on one of the pair of upper molds made possible and removing the runner generated by the previous injection from the other upper mold by using the lifting operation for mold clamping. It was configured as follows.
[0007]
The injection molding apparatus according to the present invention includes a plurality of lower molds attached to a plurality of stages including an injection stage so as to be able to circulate, and a pair of upper molds arranged on the injection stage. The mold clamping position and the retreat position can be moved alternately, and supported so as to be able to move up and down for mold clamping. A runner chuck means is provided at the retreat position of the upper mold, and the runner chuck means is the upper mold The runner attached to the mold can be grasped at the time of raising and lowering the mold clamping operation and can be removed from the mold.
[0008]
More specifically, a plurality of stages including an injection stage are set around the rotary table, and the lower mold is attached to the rotary table by attaching a lower mold to the plurality of locations and rotating the table. The first upper mold that is clamped to the lower mold that has reached the injection stage and the second mold that is clamped to the next arrival mold are alternately moved laterally to the clamping position. The first and second upper molds are supported in such a manner that they can be moved up and down when the mold is clamped, and runner chuck means are provided at a retracted position from the mold clamping position of the first and second upper molds. The remaining runner can be gripped, and the runner can be removed from the upper mold by using the up-and-down movement of the upper mold.
[0009]
By comprising in this way, a runner can be removed from the upper mold | type currently retracted sideways using the raising / lowering operation | movement of the upper mold | die of one injection | pouring operation | movement. Therefore, the runner removal work from the upper mold, which cannot be clamped for the next injection unless it is removed for the next injection, is performed between the other upper mold and the lower mold that has reached the injection stage. This can be done during the injection molding operation. As a result, preparation for the next injection is completed, so it is not necessary to set a waiting time for runner removal, and the overall molding cycle time can be reduced.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of an injection molding method and apparatus according to the present invention will be described in detail with reference to the drawings.
[0011]
1 to 3 show an overall perspective view, a front view, and a side view of an injection molding apparatus. As shown in these drawings, in the injection molding apparatus, a rotary table 12 is arranged at a substantially central position of a base 10, and a lower molding die 14 is formed at four positions on the peripheral edge of the rotary table 12. At an equiangular position of 90 degrees. The details of the rotary table 12 equipped with the molding lower die 14 are shown in FIGS. 4 to 5, and a roller gear mounted on the base 10 using a motor 16 attached to the lower part of the base 10 as a drive source. It is attached to the cam unit 18 and supported so as to rotate intermittently by 90 degrees in one direction. A slit cam photo sensor 20 is attached to the roller gear cam unit 18 so that the rotation stop position can be accurately detected. As shown in FIG. 5, the lower mold 14 disposed at four locations around the rotary table 12 is fixed to a mold base 24 that is guided up and down by a lift guide 22 fixed to the rotary table 12. The mold base 24 is lifted from the turntable 12 by raising the mold base 24 and is matched with a molding upper mold 26 described later.
[0012]
As shown in FIG. 6, an injection stage 28 </ b> A (see FIG. 6) that discharges resin to the upper and lower molds clamped is provided around the outer periphery of the rotary table 12 provided with four such lower molds 14. Middle (1)), material removal stage 28B for removing the molded product from the mold (2 in the figure), insert member supply stage 28C for loading magnet material as an insert member into the lower mold 14 (▲ in the figure) 3)) and four stages of detection stages 28D ((4) in the figure) for detecting whether or not the insert member is raised from the lower mold 14 and whether or not it is loaded are set. The rotary table 12 is rotationally driven and controlled so that each of the mounted lower molds 14 rotates at intervals of 90 degrees corresponding to the four stages and stops. Accordingly, the lower molds 14 mounted on the four positions of the rotary table 12 are simultaneously positioned on the respective stages 28A to 28D, and circulate and move through the respective stages 28A to 28D by rotation. Work, material supply work, and magnet material detection work can be performed. By such a rotary system, the injection molding of the insert member can be performed efficiently.
[0013]
By the way, a pair of upper molds 26A and 26B are disposed on the injection stage 28A, corresponding to the lower mold 14 that has been moved to the injection stage 28A by the rotary table 12. The pair of upper molds 26A and 26B are supported so as to be able to reciprocate laterally so that the mold clamping position and the retracting position can be alternately moved, and are supported so as to be able to move up and down for mold clamping. That is, as shown in FIGS. 2 and 7 to 8, a vertically movable plate 34 that is pushed up by a clamping pin described later and can be lowered by a lifting cylinder 32 with respect to a frame 30 erected on the base 10. A slider 36 that is movable reciprocally to the side is attached to the upper part of the vertical movable plate 34. A pair of upper molds 26A and 26B are fixed to the front surface of the slider 36, and one upper mold 26A (26B) corresponds to the lower mold 14 that has moved to the injection stage 28A and the position where the mold can be clamped, The other upper mold 26B (26A) corresponds to the side mold clamping standby position. Thus, the upper molds 26A and 26B can be moved alternately between the mold clamping position and the retracted position by driving the slider 36. And the runner chuck | zipper means 38 (38A, 38B) which removes the runner produced by the last injection from an upper metal mold | die is provided in the stand-by position set on both sides of the mold clamping position.
[0014]
A specific configuration of the runner chuck means 38 is shown in FIGS. A support plate 40 that can be moved up and down by a lifting cylinder 39 is disposed in parallel with the transverse movement line of the upper mold 26 (26A, 26B), and is directed to the standby position of the upper mold 26 at both left and right ends of the support plate 40. Arm 42 (42A, 42B) is provided. A chuck 46 capable of holding a runner 44 protruding from the upper surface of the upper mold 26 that has reached the standby position is provided at the lower end of the tip of the arms 42A, 42B, and a sensor 48 for detecting the presence or absence of the runner 44. Is attached. Such runner chuck means 38A, 38B are used when one upper mold 26A (or 26B) enters a clamping operation with respect to the lower mold 14 located on the injection stage 28A. The runner 44 of 26B (or 26A) is gripped, and the runner 44 is removed from the upper mold 26 by using the operation of lowering the lower mold 14 for releasing the mold. In the embodiment, the support plate 40 is simultaneously lifted when the lower die 14 is lowered, and the runner 44 is forcibly pulled up. Below these runner chuck means, runner chutes 50 (50A, 50B) are arranged (see FIGS. 7 and 8), and the upper die 26 with the runner 44 removed is moved to the injection position, and there are no obstacles below. Sometimes, the chuck 46 is opened, and the runner is discarded due to natural fall.
[0015]
Here, the mold clamping mechanism for performing the injection operation is configured as follows. As shown in FIGS. 2 to 3, an AC servo motor 52 is arranged at the lower part of the base 10, and a pair of left and right ball screws 56 are projected above the base 10 by the conductive belt 54 wound around the motor 52. I am letting. In the upper part of the base 10, an elevating base 58 is disposed on the lower surface side of the rotary table 12, and the elevating base 58 is screwed to the ball screw 56. Therefore, the lift base 58 can be moved up and down by the operation of the servo motor 52. A mold clamping pin 60 protrudes from an intermediate portion of the elevating base 58 sandwiched by a screwed portion with the ball screw 56, and the pin position is set so that it matches the injection center in the injection stage 28A. The mold clamping pin 60 pushes up the mold base 24 of the rotary table 12 described above, causes the lower mold 14 to be aligned with the upper mold 26 that is waiting at the mold clamping center position, and then further raised. Thus, the mold is clamped by coming into contact with the injection unit 62 disposed above the upper mold 26. Therefore, by operating the mold clamping pin 60 by the servo motor 52 of the lower drive source, as shown in FIG. 5, from the mold opening position ((1) in the same figure), the upper mold 26 of the lower mold 14 After the mold matching operation, the mold clamping operation ((2) in FIG. 2) is performed continuously by pressing the molds 14 and 26 thus matched together against the injection unit 62 to obtain a mold clamping force.
[0016]
In order to clamp the mold, the injection unit 62 is attached to an injection unit fixing frame 64 that is overhanging directly above the injection stage 28A, and receives the clamping force at the injection unit fixing frame 64. ing. That is, the unit mounting base 66 is horizontally disposed on the fixed frame 64, and is suspended from the mounting base 66 so that the nozzle center of the injection unit 62 coincides with the mold clamping center.
[0017]
The injection molding method of the embodiment configured as described above is as follows. By rotating the rotary table 12 intermittently by 90 degrees by the slit cam photosensor 20, the lower mold 14 of the rotary table 12 is simultaneously positioned on a plurality of stages 28A to 28D including the injection stage 28A, and each stage 28A. Cycle through ~ 28D. As shown in FIG. 11, the working mode after the lower mold 14 reaches the injection stage 28A is as follows. The mold clamping pin 60 is in the lower position, one upper mold 26A is located at the mold clamping center, and the other The upper mold 26B is in the side standby position on the right side in the figure (A in the figure). The standby position is located on the left and right of the mold clamping position, but the runner chuck means 38A removes the runner 44 removed from the upper mold 26A at the left standby position in the drawing. From this state, the mold clamping pin 60 is pushed up to enter a mold clamping operation (FIG. B). The mold clamping pin 60 pushes up the lower mold 14 to align with the upper mold 26 </ b> A, and further rises and presses against the nozzle of the injection unit 62 to perform mold clamping. At this time, the upper mold 26A and the other upper mold 26B adjacent to the upper mold 26A are attached to a common slider 36, and the slider 36 enters the ascending mode by the elevating cylinder 34 by the vertical movable plate 34. The runner 44 attached to the upper mold 26B at the standby position is in a state where it can be gripped by the runner chuck means 38B. Then, the runner chuck means 38B clamps the runner 44 remaining in the upper mold 26B on the right side by the previous injection (FIG. C). During this time, injection is performed, and resin is filled in a cavity formed between the lower mold 14 and the upper mold 26A.
[0018]
After such an injection operation and clamping of the runner 44 are performed, the mold clamping pin 60 is lowered and the mold is opened (D in the figure). The upper mold 26A is lowered to the initial height position by this mold opening operation, and the runner 44 is removed from the nozzle by moving away from the injection nozzle. At this time, since the upper mold 26B in the standby position is also lowered simultaneously, the runner 44 held by the runner chuck means 38B is removed from the standby mold 26B. By this operation, the upper mold 26B in the standby position becomes ready for molding, and the runner 44 remains in the upper mold 26A subjected to injection molding, so that the pair of upper molds 26A and 26B is moved to the slider 36. As a result, the whole moves to the left (Fig. E), and the upper die 26 is replaced. Then, the runner chuck means 3 is lowered and the presence or absence of the runner 44 of the upper mold 26A moved to the standby position is detected by the sensor 48, and the chucking posture is entered (F in FIG. 5).
[0019]
Thereafter, the state is the same as that shown in FIG. 11A, the rotary table 12 is rotated 90 degrees, the next lower mold 14 is moved to the injection stage 28A, and the runner gripped by the runner chuck means 38B. 44 is released and discarded through the runner chute 50. Thereafter, the same mode is repeated with the lower mold 14 replaced and the upper mold 26B replaced. And by rotation of the turntable 12, in each stage 28A-28D, injection | emission, product taking-out, loading of the magnetic material which is an insert member, the presence or absence of a magnetic material, and a float detection are performed.
[0020]
FIG. 12 is a time chart of the above-described operation, and the operation mode of each element described above can be understood from the same drawing.
[0021]
As described above, in the present embodiment, in the injection stage 28A, the pair of upper molds 26 is arranged with respect to the lower mold 14 that is sequentially moved by the rotary table 12, and one of them is a mold clamping operation for injection. Since the runner 44 is removed from the other upper mold 26 during the entry, the mold clamping to the lower mold 14 that arrives one after another can be performed in a short cycle time. Therefore, it is necessary to take out before entering the injection while simultaneously performing the operations necessary for molding in the respective stages 28A to 28D in which a plurality of lower molds 14 provided on the periphery of the rotary table 12 are arranged in the periphery. Since the runner 44 is removed by using the mold clamping operation, the rotary injection device can be operated in a shorter cycle. In the case of the embodiment, a manufacturing cycle for obtaining one product can be realized in one second while a single cavity is formed by upper and lower molds. As a result, the product manufacturing cycle time can be substantially halved compared to the conventional rotary injection device.
[0022]
【The invention's effect】
As described above, according to the present invention, a plurality of lower molds attached to a plurality of stages including an injection stage so as to be able to circulate, and a pair of upper molds arranged on the injection stage, the pair of upper molds are arranged. The mold is supported so that it can be moved up and down for mold clamping while allowing the mold clamping position and the retracting position to move alternately. A runner chuck means is provided at the retracting position of the upper mold, and the runner chuck means The runner attached to the mold can be grasped when lifting and lowering the mold clamping operation so that it can be removed and removed from the mold. On the injection stage, the mold clamping position and the retracted position can be moved alternately. In addition to making injection, the runner generated by the previous injection is removed from the other upper mold by using the lifting and lowering operation for clamping, greatly increasing the molding cycle time of insert molded products. Excellent effect can be shortened can be obtained.
[Brief description of the drawings]
FIG. 1 is an overall perspective view of an injection molding apparatus according to an embodiment.
FIG. 2 is a front view of the injection molding apparatus according to the embodiment.
FIG. 3 is a side view of the injection molding apparatus according to the embodiment.
FIG. 4 is a plan view and a side view of a rotary table portion.
FIG. 5 is a cross-sectional view showing a mold open state and a mold clamp state of a mold.
FIG. 6 is an explanatory schematic diagram of a stage around a rotary table.
FIG. 7 is a side view of the apparatus showing the lifting mechanism portion of the upper mold.
FIG. 8 is a front view of FIG. 7;
FIG. 9 is a plan view and a front view of a runner chuck means.
FIG. 10 is a side view of the runner chuck means.
FIG. 11 is an explanatory diagram of a mold operation in an injection stage.
FIG. 12 is a time chart showing the operation of each element in the injection stage.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Base 12 Turntable 14 Molding lower mold 16 Motor 18 Roller gear cam unit 20 Slit cam photo sensor 22 Lifting guide 24 Mold base 26 Molding upper mold 28A Injection stage 28B Material removal stage 28C Insert member supply stage 28D Detection stage 30 Frame 32 Elevating cylinder 34 Vertical movable plate 36 Slider 38 Runner chuck means 39 Lifting cylinder 40 Support plate 42 Arm 44 Runner 46 Chuck 48 Runner sensor 50 Runner chute 52 AC servo motor 54 Wrap conductive belt 56 Ball screw 58 Elevating base 60 Mold clamping pin 62 Injection unit 64 Injection unit fixing frame

Claims (3)

The lower mold simultaneously located on a plurality of stages including the injection stage is circulated and moved, and the mold clamping injection is performed on one of a pair of upper molds that can alternately move the mold clamping position and the retracted position on the injection stage. An injection molding method characterized by repeatedly molding the runner generated by the previous injection from the other upper mold by using an elevating operation for mold clamping. A plurality of lower molds that are mounted so that a plurality of stages including the injection stage can be circulated and a pair of upper molds are arranged on the injection stage, and the pair of upper molds are alternately moved between a clamping position and a retracted position. The runner chuck means is provided at the retracted position of the upper mold, and the runner chuck means lifts and lowers the runner attached to the upper mold in the mold clamping operation. An injection molding device characterized in that it can be sometimes grasped and removed from a mold. A plurality of stages including an injection stage are set around the rotary table, and a lower mold is attached to the rotary table at a plurality of locations to rotate the table so that the lower mold can be circulated and moved to the stage. At the injection stage, a first upper mold that is clamped to the lower mold that has reached and a second mold that is clamped to the next arrival mold are alternately mounted to the clamping position so that they can be laterally moved and clamped The runner chuck means is provided at the retracted position from the clamping position of the first and second upper molds so that the runner remaining in the upper mold can be gripped by the previous injection. An injection molding apparatus characterized in that the runner can be removed from the upper mold by using the up-and-down movement of the upper mold.

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