JP2007090790A - Resin molding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin molding apparatus capable of improving a clamping precision of a mold even with a low clamping force. <P>SOLUTION: The resin molding apparatus comprises a movable side platen 35 for holding the movable side mold 30 for a fixed side platen 25 for holding a fixed side mold 20 being connected through a tie-bar 40. A locating ring 61 and 62 are respectively mounted at the fixed side mold 20 and the movable side mold 30 and the locating ring 61 and 62 are engaged with a locating hole 26 and 36 which are set up respectively at the fixed side platen 25 and the movable side platen 35. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin molding apparatus, and more particularly to a resin molding apparatus suitable for molding small optical components such as lenses.

  Usually, an apparatus for injection molding a small part has a clamping force of about 30 to 50 tons. The present inventors have examined an injection molding apparatus that operates with a clamping force of about 5 to 15 tons for injection molding of minute optical components such as microlenses. If the clamping force is reduced, the resin injection pressure can be reduced, the mold can be reduced, and the amount of resin discarded per molding is reduced, which is advantageous in terms of cost. However, it is necessary to increase the mold clamping accuracy of the mold. For example, it is necessary to suppress the axial displacement between the molds and to minimize the displacement and deformation of the molding space due to temperature fluctuation.

  By the way, since the mold deteriorates as the molding cycle increases, it is necessary to replace it periodically. Conventionally, as described in Patent Document 1, only the fixed side platen is provided with a locate hole and a locate ring. At the time of mold setup, the mold was attached using the locate ring as a guide, and the four corners of the mold were screwed to the platen.

However, in the conventional resin molding equipment, the inner diameter of the locate hole is set with a large tolerance considering the workability of setup, so the mold clamping accuracy is low, and the fixed side mold and the movable side mold This is incompatible with injection molding of minute optical components with a low clamping force. In addition, since the four corners of the mold are bolted to the platen, when the mold temperature fluctuates due to continuous molding or the like, the deformation of the mold also increases.
JP 2005-199651 A

  Therefore, an object of the present invention is to provide a resin molding apparatus that can improve the mold clamping accuracy of a mold even with a low mold clamping force.

  In order to achieve the above object, the present invention provides a resin molding apparatus in which a movable platen holding a movable mold is connected to a fixed platen holding a fixed mold via a tie bar. A locating member is provided in each of the mold and the movable side mold, and the locating member is fitted in a locating hole provided in each of the fixed side platen and the movable side platen.

  In the resin molding apparatus according to the present invention, the locating member is provided on the stationary mold, the locating member is also provided on the movable mold, and the locating members are provided in the locating holes provided on the stationary platen and the movable platen. Since each is fitted, the mounting accuracy at the time of mold setup is improved, the shaft misalignment is extremely small, and a fine molded product with good quality can be obtained even with a low clamping force.

  In the resin molding apparatus according to the present invention, it is preferable that each locating member is provided at the center of the fixed side mold and the movable side mold. During continuous molding, the mold temperature also varies due to variations in ambient temperature, and a slight deformation shift occurs in the molding space in the mold. By providing the locating member at the center of each of the fixed-side and movable-side molds, it is possible to effectively suppress the deformation deviation of the molding space due to the temperature variation of the mold.

  The inner diameter tolerance of each locate hole is preferably 0.01 mm or less, and more preferably 0.005 to 0.01 mm. Further, the coaxiality of the fixed side locate hole and the movable side locate hole is preferably 0.05 mm or less.

  Moreover, it is preferable to provide a member that restricts rotation of the fixed side mold and the movable side mold with respect to the fixed side platen and the movable side platen. For example, if a knock pin is inserted from each mold into a hole provided in each platen, each mold can be effectively prevented from rotating.

  Furthermore, the inner peripheral surface of the locate hole and the outer peripheral surface of the locate member may be tapered surfaces. According to the fitting of the tapered surfaces, workability at the time of setup is improved. In this case, a gasket may be inserted between the locate hole and the locate member. By interposing the gasket, workability and positioning accuracy during setup can be improved.

  It is preferable that the fixed side platen and the fixed side mold, and the movable side platen and the movable side mold are fixed, respectively. For example, each may be coupled by magnetic force. Alternatively, each locating member may be fixed to the fixed side platen and the movable side platen by a nut screwed to a screw formed on the outer peripheral surface thereof.

  Hereinafter, embodiments of a resin molding apparatus according to the present invention will be described with reference to the accompanying drawings.

(Refer to the first embodiment, FIGS. 1 and 2)
FIG. 1 shows a resin molding apparatus 1A according to the first embodiment of the present invention. The resin molding apparatus 1 </ b> A fixes a fixed platen 25 that holds a fixed mold 20 on a base 10, and a tie bar 40 that moves a movable platen 35 that holds a movable mold 30 relative to the fixed platen 25. Are provided so as to be movable in the horizontal direction (arrow A, A ′ direction). The tie bars 40 are set at the four corners of the platens 25 and 35.

  The movable platen 35 can be moved in the horizontal direction by a drive mechanism (not shown). The molds 20 and 30 are clamped by moving in the direction of arrow A, and the mold is opened by moving in the direction of arrow A ′. In the first embodiment, the clamping force is assumed to be about 5 to 15 tons.

  As shown in FIG. 2, the internal structure of each mold 20, 30 includes a base mold 21, 31, cavities 22, 32, and a core, respectively. For example, eight micro optical parts (resin lenses) can be molded in one injection cycle. Here, the member in which the transfer portion of the optical surface of the resin lens is formed is referred to as a core, and the member in which the transfer portion of the flange portion is formed is referred to as a cavity.

  A runner 52 communicates with the molding space 51 through a gate 53. An injection unit (not shown) enters the back portion of the fixed mold 20 from the inside of the locate ring 61 described below from the direction of arrow X, and the molten resin injected from the injection unit enters the molding space 51 from the runner 52 through the gate 53. Filled.

  On the other hand, locating rings 61 and 62 are respectively provided in the center portions on the vertical surfaces of the fixed side mold 20 and the movable side mold 30, and the fixed side platen 25 and the movable side platen 35 are respectively provided with locating holes 26 and 36. Is provided. The locating rings 61 and 62 are fitted in the locating holes 26 and 36, respectively.

  As described above, the locating ring 61 is provided on the fixed mold 20, the locating ring 62 is also provided on the movable mold 30, and the locating rings 61 and 62 are provided on the fixed platen 25 and the movable platen 35. Since it is fitted to the locating holes 26 and 36 respectively, the mounting accuracy at the time of mold setup is improved, the shaft misalignment of both molds 20 and 30 is extremely small, and fine molding with good quality even with a low clamping force. Goods can be obtained.

  By the way, at the time of continuous molding, the mold temperature rises as the ambient temperature rises, and the amount of misalignment of the molds 20 and 30 varies. In the resin molding apparatus 1A, the locating rings 61 and 62 are provided at the central portions of the fixed mold 20 and the movable mold 30, so that the starting point of linear expansion due to temperature fluctuations of the molds 20 and 30 is the center. It becomes a part (namely, locating ring 61,62), and the deformation | transformation and deviation | shift of the shaping | molding space part 51 arrange | positioned radially from this center part are canceled.

  The inner diameter tolerance of each of the locate holes 26 and 36 is preferably 0 to 0.01 mm in consideration of suppressing the amount of axial deviation and workability when fitting the locate rings 61 and 62. More preferably, it is 005 to 0.01 mm. For example, when locating rings 61 and 62 having a clearance of 0.01 mm are fitted to such locating holes 26 and 36, a maximum axial displacement of 0.02 mm occurs during continuous molding. become. Therefore, it is preferable to use a high linear expansion material for the locating rings 61 and 62. Since the molds 20 and 30 are set up at room temperature, the fitting workability can be ensured. On the other hand, when the temperature rises, the locating rings 61 and 62 are greatly expanded, so that the clearance is clogged, and the shaft deviation hardly occurs.

  In addition, the coaxiality of the fixed locating hole 26 and the movable locating hole 36 is preferably zero from the viewpoint of preventing axial misalignment. However, when the molds 20 and 30 are assembled, a shaft exceeding 0.05 mm is used. The deviation is allowed, and the axial deviation in the initial state is suppressed to 0.05 mm or less by adjusting the molds 20 and 30 after assembling.

  In the present resin molding apparatus 1A, it is necessary to regulate the rotation of the fixed mold 20 and the movable mold 30 with respect to the fixed platen 25 and the movable platen 35 around the locating rings 61 and 62. For example, if a knock pin is inserted from the base molds 21 and 31 of the molds 20 and 30 into the holes provided in the platens 25 and 35, the molds 20 and 30 can be effectively prevented from rotating.

(Refer to the second embodiment, FIG. 3)
FIG. 3 shows a resin molding apparatus 1B according to the second embodiment of the present invention. This resin molding apparatus 1B basically has the same configuration as that of the first embodiment. Therefore, in FIG. 3, the same members as those in FIG.

  In the second embodiment, one end of each locating ring 61, 62 is extended outward to form screws 61a, 62a on the outer peripheral surface thereof, and nuts 63, 64 screwed to the screws 61a, 62a respectively. The molds 20 and 30 are fixed to the platens 25 and 35, respectively. As described above, by using both the positioning by the locating rings 61 and 62 and the fixing method not using the bolting for the respective molds 20 and 30, the distortion of the molds 20 and 30 due to the temperature rise can be eliminated as much as possible. .

  In order to fix the molds 20 and 30 to the platens 25 and 35 without using bolts, various methods other than using the nuts 63 and 64 can be used. For example, the platens 25 and 35 can be used. The base molds 21 and 31 may be coupled by magnetic force.

(Refer to the third embodiment, FIG. 4)
FIG. 4 shows a resin molding apparatus 1C according to a third embodiment of the present invention. This resin molding apparatus 1C basically has the same configuration as that of the first embodiment. Therefore, in FIG. 4, the same members as those in FIG.

  In the third embodiment, tapered surfaces having the same angle are formed on the inner peripheral surfaces of the locate holes 27 and 37 and the outer peripheral surfaces of the locate rings 71 and 72, respectively, and are fitted through the gaskets 28 and 38. ing. According to the fitting by the tapered surface, workability at the time of setup is improved. Further, by interposing the gaskets 28 and 38, it is possible to improve workability and positioning accuracy during setup.

(Other examples)
The resin molding apparatus according to the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist. For example, the details of the configuration of the fixed side and movable side molds and the configuration of each platen are arbitrary.

It is the elevation which cut off a part which shows 1st Example of the resin molding apparatus which concerns on this invention. It is sectional drawing which shows the principal part of the internal structure of a metal mold | die. It is the elevation which cut off a part which shows 2nd Example of the resin molding apparatus which concerns on this invention. It is the elevation which cut off a part which shows 3rd Example of the resin molding apparatus which concerns on this invention.

Explanation of symbols

1A, 1B, 1C ... resin molding device 20 ... fixed side mold 25 ... fixed side platen 26,27 ... locating hole 28 ... gasket 30 ... movable side mold 35 ... movable side platen 36, 37 ... locating hole 38 ... gasket 40 ... Tie bar 61,62,71,72 ... Locating ring 63,64 ... Nut

Claims (9)

In a resin molding apparatus in which a movable platen holding a movable mold is connected to a fixed platen holding a fixed mold via a tie bar,
A locating member is provided for each of the fixed side mold and the movable side mold,
The locating member is fitted in a locating hole provided in each of the fixed side platen and the movable side platen;
A resin molding device.   2. The resin molding apparatus according to claim 1, wherein each of the locating members is provided at a center portion of the fixed mold and the movable mold. 3.   The resin molding apparatus according to claim 1 or 2, wherein an inner diameter tolerance of each locating hole is 0.01 mm or less.   4. The resin molding apparatus according to claim 1, wherein the coaxiality of the fixed side locate hole and the movable side locate hole is 0.05 mm or less.   The member according to any one of claims 1 to 4, further comprising a member that restricts rotation of the fixed-side mold and the movable-side mold with respect to the fixed-side platen and the movable-side platen. The resin molding apparatus as described.   The resin molding apparatus according to claim 1, wherein an inner peripheral surface of the locate hole and an outer peripheral surface of the locate member are respectively tapered surfaces.   The resin molding apparatus according to claim 6, wherein a gasket is inserted between the locate hole and the locate member.   8. The resin molding according to claim 1, wherein the fixed side platen and the fixed side mold, and the movable side platen and the movable side mold are coupled by magnetic force. apparatus. 8. Each of the locating members is fixed to the stationary platen and the movable platen by a nut screwed to a screw formed on an outer peripheral surface thereof. The resin molding apparatus described in 1.

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