JP2008229868A - Injection molding machine and molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine which can produce a high accuracy molding by precisely clamping a fixed mold and a movable mold and a molding method using the injection molding machine. <P>SOLUTION: When an ejector 50 is operated during mold closing, by vibration generated from a Y movement part 53 and an X movement part 54, a fixed platen 31 and a movable platen 33 are vibrated so that the mold matching accuracy between the fixed mold 61 and the movable mold 63 is apt to decline. When a mold is closed while the Y movement part 53 is held at the stock position of a dotted line, the mold matching accuracy between the fixed mold 61 and the movable mold 63 declines largely. For this season, during mold closing, the Y movement part 53 is held at a fundamental position just above the middle of the fixed platen 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an injection molding apparatus for molding an optical component or the like using a mold and a molding method using the injection molding apparatus.

There is an injection molding apparatus that clamps a fixed mold and a movable mold between a fixed platen and a movable platen (for example, see Patent Document 1).
JP 2006-272558 A

  In the injection molding apparatus as described above, in order to take out the molded product remaining in one of the molds after the mold is opened, a take-out device having a hand for gripping the molded product is usually provided. Such a take-out device is generally fixed to the upper part of the fixed platen from the viewpoint of workability and stability.

  However, the present inventor has found that the operation of the take-out device as described above has an influence on the shape accuracy of the molded product based on examinations on experiments, trial manufacture, and the like. That is, the take-out device can hold the molded product and move it three-dimensionally, so that the movable part has a considerable weight. For this reason, when the molded product is conveyed to an external stocker, the position of the center of gravity in the horizontal direction largely moves due to the movement of the movable part, and the fixed platen and thus the fixed mold are slightly rotated around the horizontal axis. As a result, a minute shift occurs between the fixed mold and the movable mold, and the shape accuracy of the molded product is lowered.

  Therefore, the present invention provides an injection molding apparatus capable of manufacturing a highly accurate molded product by mold clamping in which a fixed mold and a movable mold are precisely aligned, and a molding method using the injection molding apparatus. For the purpose.

  In order to solve the above-described problems, an injection molding apparatus according to the present invention includes (a) a fixed platen to which a fixed mold is attached and a movable platen to which a movable mold is attached, and between the fixed platen and the movable platen during molding. A molding apparatus main body that clamps the fixed mold and the movable mold by sandwiching the fixed mold and the movable mold, and (b) a movable portion that is attached to the molding apparatus main body and performs an operation of carrying a molded product molded by the molding apparatus main body. The accessory device, and (c) a drive that controls the operation of the molding device main body and the accessory device to cause the accessory device to hold the position of the center of gravity in the horizontal direction of the accessory device when the movable platen is operated to close the mold. And a control device. Here, the mold closing means that the movable platen is operated so as to join the fixed mold and the movable mold, and the fixed mold and the movable mold are joined at the necessary pressure from the time when the mold starts to close. This means until mold matching is completed, and does not include a state where mold closing is completed and the mold clamping state is continued.

  In the above injection molding apparatus, when the drive control device operates the movable platen to close the mold, the auxiliary device maintains the position of the center of gravity in the horizontal direction, so that the left and right weight balance of the auxiliary device is substantially maintained. The stationary platen and the movable platen can be prevented from being displaced relative to each other by the influence of the accessory device, that is, from being misaligned. In other words, the fixed mold and the movable mold can be prevented from being misaligned with the operation of the accessory device at the time of mold closing, and the mold alignment at the time of mold closing can be made highly accurate. Shape accuracy can also be improved.

  According to a specific aspect or aspect of the present invention, in the injection molding apparatus, when the drive control device opens the mold by operating the movable platen and when closing the mold by operating the movable platen. The center-of-gravity position in the horizontal direction of the accessory device is matched. Here, the mold opening means from the time when the mold clamping state is finished to the time when the mold is opened to the time when the operation for separating the fixed mold from the movable mold is completed. Does not include the state of continuing. In this case, when the mold is opened, the fixed mold and the movable mold can be prevented from being displaced due to the operation of the accessory device. Misalignment can be prevented when closing.

  Further, in another aspect of the present invention, in a state where the drive control device applies pressure to the movable platen and clamps the fixed mold and the movable mold, the movable portion of the auxiliary apparatus is connected to the auxiliary apparatus. The center of gravity in the horizontal direction is moved. In this case, since both the molds are not easily affected by the operation of the accessory device by clamping the fixed die and the movable die, the accuracy of mold matching is hardly deteriorated even if the position of the center of gravity of the accessory device moves.

  In yet another aspect of the present invention, the drive control device moves the movable part of the auxiliary device to move up and down during the period from the completion of mold opening to the start of mold closing. In this case, since the auxiliary device is allowed to move up and down during the period excluding mold clamping, the auxiliary device can be used effectively during this period.

  In yet another aspect of the present invention, the accessory device has a hand for gripping a molded product, is fixed on a fixed platen, and remains on the fixed mold side or the movable mold side when the mold is opened or after the mold is opened. Is a take-out device for taking out the outside. In this case, it is possible to prevent the fixed platen from rotating around, for example, the horizontal axis in accordance with the operation of the take-out device, and it is possible to prevent the accuracy of the molded product from being lowered due to the operation of the take-out device.

  A molding method according to the present invention includes a molding apparatus main body that clamps a fixed mold and a movable mold between a fixed platen and a movable platen during molding, and a molding apparatus main body that is attached to the molding apparatus main body. A molding method using an injection molding apparatus including an accessory device having a movable part that performs an operation of carrying a molded product molded by the method, wherein when the mold is closed by moving the movable platen, the horizontal direction of the accessory device The center of gravity position is maintained.

  In the above molding method, when the mold is closed by moving the movable platen, the center of gravity position of the auxiliary device in the horizontal direction is held, so that the weight balance between the left and right of the auxiliary device is substantially maintained, and the fixed platen is affected by the influence of the auxiliary device. It is possible to prevent the movable platen from being displaced relative to each other, that is, from being misaligned. Thereby, it is possible to increase the accuracy of mold matching when closing the mold, and it is possible to improve the shape accuracy of the molded product.

  According to a specific aspect of the present invention, in the molding method described above, the center of gravity in the horizontal direction of the accessory device is moved during mold clamping.

  An injection molding apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view illustrating the injection molding apparatus according to the present embodiment, and FIG. 2 is a view taken along the line AA of the injection molding apparatus of FIG.

  The injection molding apparatus 10 includes a support frame 20, a fixed platen 31, a movable platen 33, a rear platen 35, an opening / closing drive device 40, a take-out device 50, and an injection device 70. Among these, the support frame 20, the fixed platen 31, the movable platen 33, the rear platen 35, and the opening / closing drive device 40 are disposed between the fixed platen 31 and the movable platen 33. Is formed into a molding apparatus main body that enables molding by clamping the molds 61 and 63 together. Further, the take-out device 50 is an incidental device that performs operations related to molding in association with the molding device main body.

  In the injection molding apparatus 10, the support frame 20 is a pedestal for supporting each part of the injection molding apparatus 10, and a fixed platen 31 and a rear platen 35 are precisely placed on the upper portion thereof by a fixing device (not shown). It is positioned and supported and fixed with vibrations suppressed.

  The fixed platen 31 is fixed to the upper surface on the center side of the support frame 20 with a strength capable of withstanding mold clamping (that is, lock-up) during molding, and supports the take-out device 50 on the upper portion thereof. An inner side 31 a of the fixed platen 31 detachably supports the fixed mold 61 and faces the inner side 33 a of the movable platen 33.

  The movable platen 33 is supported by a slide guide 41, which will be described later, so as to be reciprocally movable in the ± X directions. The inner side 33 a of the movable platen 33 supports the movable mold 63 so as to be detachable, and faces the inner side 31 a of the fixed platen 31.

  The rear platen 35 is fixed to the upper surface on the end side of the support frame 20 with a strength that can withstand mold clamping (ie, lock-up) during molding. However, the position of the rear platen 35 can be adjusted in the ± X directions. The interval between the movable platen 31 and the movable platen 33 can be adjusted. The rear platen 35 supports the movable platen 33 from behind via a toggle mechanism 45 of the opening / closing drive device 40 during mold clamping.

  The opening / closing drive device 40 includes a slide guide 41, tie bars 43 a and 43 b, a toggle mechanism 45, and an actuator 47.

  In the opening / closing drive device 40, the slide guide 41 is provided on the support frame 20 and directly below the movable platen 33, and supports the movable platen 33 and allows the movable platen 33 to smoothly reciprocate in the ± X directions. It is possible.

  The upper tie bar 43a and the lower tie bar 43b are installed between the fixed platen 31 and the rear platen 35, respectively. There are actually two upper tie bars 43a and two lower tie bars 43b, which are supported by the four corners of the fixed platen 31 and the rear platen 35 and extend in the X direction in parallel with each other. At the four corners of the movable platen 33, through holes for penetrating the tie bars 43a and 43b are formed, and guide bushes 33d are provided in these through holes. The movable platen 33 is slidable with respect to the tie bars 43a and 43b, and is reciprocated in the ± X directions while being guided by the slide guide 41 and the tie bars 43a and 43b.

  The toggle mechanism 45 includes first and second toggle portions 45a and 45b each formed of a member such as a toggle link 45d, and is spanned between the movable platen 33 and the rear platen 35. The first and second toggle portions 45 a and 45 b expand and contract in response to the driving force from the actuator 47. That is, the movable platen 33 can be moved toward and away from the rear platen 35 so that the movable platen 33 can be pressed toward the fixed platen 31 with a desired pressure. Thereby, the movable platen 33 and the fixed platen 31 can be tightened so as to be close to each other, and the fixed mold 61 and the movable mold 63 sandwiched between them can be closed, or the movable platen 33 can be closed. The fixed mold 61 and the movable mold 63 that are sandwiched between the fixed platen 31 and the fixed platen 31 can be opened. Furthermore, when the mold is closed, the movable platen 33 can be pressed against the fixed platen 31 by driving the actuator 47 with an extremely large pressure, and the fixed mold 61 and the movable mold 63 can be clamped with sufficient force. it can. The actuator 47 is configured by a mechanical mechanism type drive device such as a motor or a ball screw, or a hydraulic cylinder, and operates at a desired timing in accordance with a control signal from a control unit (not shown). Further, the toggle mechanism 45 can be omitted, and the movable platen 33 can be directly operated by the actuator 47.

  The take-out device 50 includes a base 51, a Y moving unit 53, an X moving unit 54, and a hand 55. Among these, the Y moving unit 53, the X moving unit 54, the hand 55, and the like constitute a movable unit of the take-out device 50.

  In the take-out device 50, the base 51 has a fixed portion 51 a and a guide rail 51 b, and serves as a portion for fixing and supporting the take-out device 50 on the fixed platen 31. Specifically, the fixed portion 51a is fixed to the upper surface 31c of the fixed platen 31, and the guide rail 51b is supported on the fixed portion 51a so as to extend in the Y direction, that is, in the horizontal direction.

  The Y moving portion 53 is supported by the guide rail 51b of the base portion 51, can be smoothly slid in the ± Y direction along the guide rail 51b, and supports the guide rail 53b extending in the X direction.

  The X moving part 54 is supported by a guide rail 53b extending from the Y moving part 53 and can advance and retreat in the ± X direction. As a result, the X moving part 54 can move two-dimensionally to an arbitrary position in the XY plane. Yes. In addition, the X moving unit 54 can move the support bar 55 a extending from the hand 55 up and down.

  The hand 55 is supported by the lower end of the support bar 55a of the X moving part 54, and can move to an arbitrary position three-dimensionally. Further, the hand 55 can hold the molded product MP between a pair of arm members 55b and 55b that open and close at a necessary timing. In the case where the molded product MP is an optical element, an undesired portion, such as a sprue portion or a runner portion, which is formed accompanying the molding is gripped by the hand 55 so as not to damage the optical surface.

  The injection device 70 includes a cylinder, a hopper, a screw, a screw driving unit, a heater, and the like, and can discharge a desired molten resin from the injection end 71. The injection device 70 can detachably connect the injection end 71 to the fixed platen 31, and is formed in a state where the fixed mold 61 and the movable mold 63 are clamped via the fixed platen 31. Molten resin can be supplied into the cavity at a desired timing.

  FIG. 3 is a block diagram illustrating a control system of the injection molding apparatus 10 shown in FIGS. 1 and 2. This control system includes a toggle drive unit 81, a take-out device drive unit 83, an injection device drive unit 85, and a control unit 87.

  The toggle drive unit 81 operates the toggle mechanism 45 via the actuator 47. At this time, the toggle drive unit 81 operates the toggle mechanism 45 while monitoring detection outputs of a position sensor, a pressure sensor and the like attached to the opening / closing drive device 40. The take-out device driving unit 83 operates the take-out device 50 to move the hand 55 three-dimensionally and causes the hand 55 to hold the molded product MP. At this time, the take-out device driving unit 83 operates the take-out device 50 while monitoring the detection output of a position sensor or the like attached to the take-out device 50. The injection device driving unit 85 controls the operation of the injection device 70 and adjusts the supply timing and supply pressure of the resin to the fixed platen 31.

  The control unit 87 is a drive control device for controlling the injection operation and the molding operation by the injection molding device 10, and comprehensively controls the operations of the toggle drive unit 81, the take-out device drive unit 83, and the injection device drive unit 85. is doing. That is, the control unit 87 operates the opening / closing drive device 40 via the toggle drive unit 81 to perform mold closing and mold clamping using the movable platen 33 and the fixed platen 31, and the injection device drive unit. By operating the injection device 70 through 85, the molten resin is supplied between the molds 61 and 63 at a necessary timing. Then, after the molding is completed, the control unit 87 operates the opening / closing driving device 40 via the toggle driving unit 81 to open the molds 61 and 63 and also via the take-out device driving unit 83. By operating the take-out device 50, the molded product MP is taken out from between the platens 33 and 31 and conveyed to the external stocker ST.

  FIG. 4 is a flowchart conceptually illustrating the operation of the injection molding apparatus 10 shown in FIGS. 1 and 2. 4A mainly explains the operation of the molding apparatus main body including the support frame 20, the fixed platen 31, the movable platen 33, the opening / closing drive device 40, and the like. FIG. The operation will be mainly described.

  First, the control unit 87 confirms the state of the take-out device 50 via the take-out device drive unit 83 (step S11). Specifically, it is determined whether or not the take-out device 50 has returned to the basic position. If the take-out device 50 has not returned to the basic position, the take-out device 50 is returned to the basic position. Here, that the take-out device 50 is in the basic position means that the take-out device 50 is in the position indicated by the alternate long and short dash line in FIG. That is, it means that the hand 55 is disposed above the center of the fixed platen 31.

  Next, the control unit 87 operates the opening / closing drive device 40 via the toggle drive unit 81 to start mold closing to move the movable platen 33 to the + X side (step S12). The control unit 87 operates the opening / closing drive device 40 as it is to move the movable platen 33 to the fixed platen 31 side to the mold contact position where the fixed mold 61 and the movable mold 63 come into contact with each other, and then the toggle drive unit 81. Is further operated to clamp the fixed mold 61 and the movable mold 63 with a necessary pressure. With the start of such a mold clamping state, the mold closing by the movable platen 33 and the fixed platen 31 is completed (step S13).

  In parallel with the mold closing as described above, the control unit 87 restricts the operation of the take-out device 50 via the take-out device drive unit 83. That is, the control unit 87 stops the operation of the take-out device 50 from the start of mold closing in step S12 to the completion of mold closing in step S13 (step S21), and stops the Y moving unit 53 and the hand 55. Keep in state.

  The reason for stopping the operation of the take-out device 50 during mold closing will be described. That is, when the take-out device 50 is operated while the mold is closed, the fixed platen 31 and the movable platen 33 are vibrated by vibrations generated from the Y moving unit 53 and the X moving unit 54, and the fixed mold 61 and the movable mold 63 are driven. There is a tendency that the mold matching accuracy decreases. In particular, when the molded product MP is a high-precision optical element or the like, the optical performance of the molded product MP deteriorates due to a decrease in mold matching accuracy, leading to a decrease in yield. Further, since the Y moving portion 53 supports the X moving portion 54 and has a considerable weight, the present inventor explained that the Y moving portion 53 is moved to the stock position indicated by the dotted line in FIG. 2 as described above. It has been found that if the mold is closed properly, the processing accuracy of the molded product MP decreases. That is, the Y moving portion 53 at the stock position indicated by the dotted line gives a large rotational moment to the guide rail 51b, and further gives a rotational force around the X axis to the fixed platen 31 via the fixed portion 51a. . When the Y moving portion 53 is held at the dotted stock position and the mold is closed as described above, the accuracy of mold alignment between the fixed mold 61 and the movable mold 63 is greatly reduced, and the processing accuracy of the molded product MP is reduced. A tendency to decrease was confirmed. Such a tendency occurs even if the Y moving part 53 does not move to the stock position indicated by the dotted line if the Y moving part 53 is displaced to some extent from directly above the center of the fixed platen 31. For this reason, the Y moving portion 53 is held at the basic position above the center of the fixed platen 31 during mold closing. That is, during the mold closing operation, the position of the center of gravity of the take-out device 50 in the horizontal direction, that is, the ± Y direction is held.

  Next, when the control unit 87 operates the take-out device 50 via the take-out device drive unit 83 and the hand 55 holds the molded product MP molded in the previous process, the control unit 87 keeps the molded product MP in the hand 55. Until the horizontal movement to the + Y side is started (step S22). Thus, the molded product MP held by the hand 55 can be moved to the stocker ST and arranged there. At this time, in the take-out device 50, the position of the center of gravity in the horizontal direction changes due to the movement of the movable part such as the Y moving part 53. After the mold closing is completed and the mold is clamped, the fixed mold 61 and the movable mold 63 are clamped to each other with sufficient pressure, and mold displacement is unlikely to occur. Even if it is moved to the dotted stock position, the fixed platen 31 is hardly vibrated or misaligned, and the processing accuracy of the molded product MP is not lowered.

  Next, the control unit 87 operates the injection device 70 via the injection device driving unit 85, and puts resin at a necessary pressure into the cavity between the fixed mold 61 and the movable mold 63 that are clamped. Injection for injection is performed (step S14). Then, the control unit 87 gradually cools the resin in the cavity and waits for the completion of molding (step S15).

  In parallel with this, the control unit 87 continues the operation of the take-out device 50 via the take-out device driving unit 83, and places the molded product MP on the stocker ST so that the hand 55 emptied on the guide rail 51b. While raising to a height, the horizontal movement to -Y side is started (step S23). That is, the Y moving unit 53 starts returning to the basic position above the center of the fixed platen 31.

  On the other hand, with respect to the operation of the opening / closing drive device 40, the control unit 87 waits for the completion of conveyance in which the hand 55 is disposed above the center of the fixed platen 31 and the take-out device 50 returns to the basic position (step S16). On the other hand, if the molding by the fixed mold 61 and the movable mold 63 is not completed even after the take-out device 50 completes the conveyance, the control unit 87 puts the take-out device 50 in a standby state until the molding is completed (Step S87). S24). Thereby, it is possible to avoid the Y moving portion 53 of the take-out device 50 from moving sideways when the mold is opened, and the center of gravity position of the take-out apparatus 50 in the horizontal direction, that is, the ± Y direction can be held during the mold opening operation. . As a result, the fixed mold 61 and the movable mold 63 can be prevented from being misaligned when the mold is opened, and both the molds 61 and 63 are relatively displaced immediately before the separation, and the next mold is closed. Misalignment can be prevented.

  Next, the control unit 87 confirms the completion of conveyance and the completion of molding, operates the opening / closing drive device 40 via the toggle drive unit 81, and starts mold opening to move the movable platen 33 to the -X side (step). S17). The controller 87 operates the opening / closing drive device 40 as it is, and retracts the movable platen 33 until the fixed mold 61 and the movable mold 63 are farthest from each other, thereby completing the mold opening (step S18).

  Next, the control unit 87 confirms the completion of mold opening, operates the take-out device 50 via the take-out device drive unit 83, and starts taking out the molded product MP with the hand 55 (step S25). As a result, the hand 55 moves in the −Z direction and grips an appropriate position of the molded product MP remaining in either the fixed mold 61 or the movable mold 63, and the molded product MP is transferred from both the molds 61 and 63. Is pulled back to the position where interference is avoided, and then moved in the + Z direction to complete the return to the basic position (step S26). In other words, the hand 55 returns to the same basic position in a state where the Y moving portion 53 is at the basic position above the center of the fixed platen 31. At this time, the position of the center of gravity of the take-out device 50 in the horizontal direction does not change.

  Thereafter, the process returns to step S11 and the like, and the same processing as described above is performed. That is, the mold closing is performed while holding the unloading device 50 in the basic position, and the molded product MP is transported in the horizontal direction by the unloading device 50 in a state where the mold is not displaced due to the completion of the mold closing.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications are possible. For example, the mold closing or mold opening may not be performed when the movable part of the auxiliary device other than the take-out device 50 moves in the horizontal direction.

It is a front view explaining the injection molding device of an embodiment. It is an AA arrow line view of the injection molding apparatus of FIG. It is a block diagram explaining the control system of the injection molding apparatus shown in FIG.1 and FIG.2. (A), (B) is a flowchart explaining operation | movement of an injection molding apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Injection molding apparatus, 20 ... Support frame, 31 ... Fixed platen, 33 ... Movable platen, 35 ... Rear platen, 40 ... Opening / closing drive device, 41 ... Slide guide, 43a, 43b ... Tie bar, 45 ... Toggle mechanism, 47 ... Actuator, 50 ... take-out device, 51 ... base, 51a ... fixed part, 51b ... guide rail, 53 ... Y moving part, 54 ... X moving part, 55 ... hand, 55a ... support rod, 61 ... fixed mold, 63 ... Movable mold, 70 ... Injection device, 81 ... Toggle drive unit, 83 ... Extraction device drive unit, 85 ... Injection device drive unit, 87 ... Control unit, MP ... Molded product, ST ... Stocker

Claims (7)

A fixed platen for attaching a fixed mold and a movable platen for attaching a movable mold, and clamping the mold by sandwiching the fixed mold and the movable mold between the fixed platen and the movable platen during molding A molding apparatus body for performing
Attached apparatus having a movable part attached to the molding apparatus main body and performing an operation of carrying a molded product molded by the molding apparatus main body,
By controlling the operations of the molding apparatus main body and the auxiliary device, the drive control device causes the auxiliary device to hold the center of gravity in the horizontal direction of the auxiliary device when the movable platen is operated to perform mold closing. When,
An injection molding apparatus comprising:   The drive control device matches the position of the center of gravity in the horizontal direction of the auxiliary device when the mold is opened by operating the movable platen and when the mold is closed by operating the movable platen. The injection molding apparatus according to claim 1.   The drive control device causes the movable portion of the auxiliary device to move in the horizontal direction of the auxiliary device in a state where the movable platen is pressurized and the fixed mold and the movable die are clamped. The injection molding apparatus according to any one of claims 1 and 2, wherein the operation is performed so that the position of the center of gravity moves.   The drive control device moves the movable part of the auxiliary device so as to move up and down during a period from the completion of the mold opening to the start of the mold closing. The injection molding apparatus according to any one of the above.   The accessory device has a hand for holding a molded product, is fixed on the fixed platen, and takes out the molded product remaining on the fixed mold side or the movable mold side when the mold is opened or after the mold is opened. The injection molding apparatus according to any one of claims 1 to 4, wherein A molding apparatus body that clamps a fixed mold and a movable mold between a fixed platen and a movable platen during molding, and a molded product that is attached to the molding apparatus body and molded by the molding apparatus body A molding method using an injection molding apparatus including an accessory device having a movable part that performs an operation of carrying
A molding method characterized in that when the mold is closed by moving the movable platen, the position of the center of gravity of the auxiliary device in the horizontal direction is maintained.   The molding method according to claim 6, wherein the center of gravity in the horizontal direction of the auxiliary device is moved during clamping of the fixed mold and the movable mold.

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