JP4412613B2 - Cooling mechanism of disk injection molding machine - Google Patents

Description

  The present invention relates to a cooling mechanism for an injection molding machine for a disk that injects and molds a molten resin material from the lateral direction with an injection device.

  For molding optical disk molded products such as CDs and DVDs, a disk injection molding machine is used in which a molten resin material is injected from an injection device and molded by applying a clamping pressure at a mold part. In such a disk injection molding machine, a synthetic resin material having a high temperature (about 300 ° C. to 400 ° C.) is injected from the injection device during the disk molding and flows into the mold part, so that the mold part is thermally expanded. As a result, the molding accuracy is lowered, and there is a possibility that variations in quality occur in molded products molded under the same conditions.

  Therefore, in a conventional disk injection molding machine, a heat insulating plate is disposed between a mold part and a fixed platen and a movable platen on which the mold part is arranged, or a cooling medium is provided in a main part of the mold part. A cooling mechanism that suppresses the temperature rise of the mold part is provided by a method such as forming a temperature-controlling means that controls the temperature by forming a flow path that can circulate (see, for example, Patent Document 1).

  By the way, in the cooling mechanism of the conventional disk injection molding machine as described above, even when the temperature rise of the mold part is suppressed by the heat insulating plate or the temperature control means, the mold part is discharged to the outside. Heat and heat generated from peripheral equipment, etc. are transmitted to the fixed plate, movable plate, multiple tie bars, etc., and the temperature of the fixed plate, movable plate, each tie bar etc. rises and thermally expands. As a result, there is a case where the molding accuracy is deteriorated. In particular, the fixed plate and the movable plate have different directions of thermal expansion (the fixed plate thermally expands upward, whereas the movable plate thermally expands in the vertical direction). In other words, the thermal expansion due to the temperature rise of each tie bar is not always uniform due to various external factors, so that the shift of the eccentric position (ECC) of the transfer with respect to the center hole of the disk to be formed becomes large. There was a problem.

On the other hand, it is also possible to suppress the temperature rise of the movable platen by providing a temperature control means for controlling the temperature by forming a cooling channel through which the cooling medium can flow in the movable platen, fixed platen, tie bar, etc. Although it is possible, in the case of such a configuration, it is necessary to form a cooling passage in the entire injection molding machine, resulting in a very complicated configuration. Moreover, since the opening part in which the injection device can be inserted is formed in the fixed platen, there is a problem in terms of strength.
JP 2003-31798 A

  The present invention has been made in view of the above points, and for a disc that suppresses a decrease in molding accuracy due to a temperature rise during molding of a fixed platen or a movable platen and has a simple configuration and excellent strength. A cooling mechanism for an injection molding machine is provided.

That is, the invention of claim 1 is a cooling mechanism of a disk injection molding machine for injecting and molding a molten resin material from the lateral direction by an injection device, and is vertically arranged, and the injection device is provided at a substantially central portion. And a fixed platen in which a plurality of tie bars are horizontally arranged vertically, and a movable plate that is arranged opposite to the fixed plate and advances and retreats with respect to the fixed plate along the plurality of tie bars. And a mold part composed of a fixed mold disposed on the fixed plate and a movable mold disposed on the movable plate, and an integral part of the fixed mold on the fixed plate side via a heat insulating plate A flat portion disposed between the fixed mold and the fixed plate to be in contact with the fixed plate; a cooling passage through which a coolant flows; and a locating ring on the flat portion on the fixed plate side Fixed platen side cooling system with through-holes that can be inserted through And a plane portion that is integrally formed on the movable plate side of the movable mold via a heat insulating plate, and is disposed between the movable mold and the movable plate so as to contact the movable plate. An injection molding machine for a disc having a cooling passage through which a coolant flows, and a movable plate side cooling plate in which a through hole into which a drive mechanism can be inserted is formed in a flat portion on the movable plate side . It relates to the cooling mechanism.

The invention according to claim 2 relates to the cooling mechanism of the disk injection molding machine according to claim 1, wherein each of the cooling plates is made of martensitic stainless steel and has a thickness of 12 mm to 20 mm .

The invention of claim 1 is a cooling mechanism of a disk injection molding machine for injecting and molding a molten resin material from the lateral direction by an injection device, which is erected in the vertical direction, and the injection device is fitted in a substantially central portion. A fixed platen having an insertable opening and a plurality of tie bars arranged horizontally above and below, a movable plate placed opposite to the fixed plate and moving forward and backward with respect to the fixed plate along the plurality of tie bars; A mold part composed of a fixed mold disposed on the fixed plate and a movable mold disposed on the movable plate, and a fixed plate side of the fixed mold are integrally formed via a heat insulating plate. A flat portion disposed between the fixed mold and the fixed plate so as to contact the fixed plate and a cooling passage through which a coolant flows, and a locating ring is inserted into the flat portion on the fixed plate side. A stationary platen side cooling plate in which possible through holes are formed; The cooling liquid circulates between a plane part that is integrally formed on the movable plate side of the movable mold via a heat insulating plate and is disposed between the movable mold and the movable plate so as to contact the movable plate. And a movable plate side cooling plate in which a through-hole through which the drive mechanism can be inserted is formed in the plane portion on the movable plate side, so that the cooling effect can be improved with a very simple configuration. In addition, it is possible to suppress a decrease in molding accuracy due to a temperature rise during molding of the fixed plate , the movable plate , the tie bar, and the like , and it is possible to improve the strength of the fixed plate and the movable plate.

According to a second aspect of the present invention, in the first aspect, since each of the cooling plates is made of martensitic stainless steel and has a thickness of 12 mm to 20 mm, the strength of the fixed plate and the movable plate is further improved. Can do.

The present invention will be described in detail with reference to the accompanying drawings.
1 is a perspective view of a cooling mechanism of a disk injection molding machine, FIG. 2 is a cross-sectional view of the main part of the cooling mechanism of the disk injection molding machine of FIG. 1, FIG. 3 is a front view of a cooling plate, and FIG. FIG. 5 is a plot diagram comparing the ECC of the present invention and the prior art.

As shown in FIGS. 1 and 2, the cooling mechanism 10 of the disk injection molding machine is for injecting and molding a molten resin material from the lateral direction by an injection device 11, and includes a stationary platen 20 and a movable platen 30. And a mold part 40 and a cooling plate 50. In the figure, reference numeral 12 denotes a heating cylinder of the injection device 11, 13 denotes a nozzle of the injection device 11, and 15 denotes a mold clamping mechanism including a known cylinder device for applying a mold clamping pressure when forming a disk. The mold clamping mechanism 15 may use a toggle mechanism.

  The fixed platen 20 is erected in the vertical direction, and has an opening 21 into which the injection device 11 can be fitted and inserted into a substantially central portion on the injection device 11 side, and a plurality (four in this example) of tie bars 22 (upper tie bars 22A). , 22B and lower tie bars 22C, 22D) are arranged horizontally vertically.

  The movable platen 30 is disposed opposite to the fixed platen 20, and advances and retreats with respect to the fixed platen 20 along a plurality of tie bars 22A, 22B, 22C, and 22D. The movable platen 30 according to the embodiment is operated by the mold clamping mechanism 15.

The mold part 40 includes a fixed mold 41 disposed on the fixed platen 20 and a movable mold 46 disposed on the movable platen 30. The mold part 40 in this example is a known disk molding mold, which is made of martensitic stainless steel (SUS420J2) or the like, and is placed on the stationary platen 20 side of the stationary mold 41 and the nozzle 13 of the injection device 11 during disk molding. A locating ring 42 into which is inserted is projected. The mold part 40 is configured to be detachable from the fixed platen 20 and the movable platen 30, and the locating ring 42 is positioned by engaging with the hole 21 a of the opening 21 of the fixed platen 20. Is done.

The cooling plate 50 is disposed between the mold part 40 and the fixed platen 20 and the movable platen 30 and has a flat part 51 larger than the mold part 40. By disposing the cooling plate 50 having the flat portion 51 on both the fixed platen 20 and the movable platen 30, the displacement between the molds caused by the thermal expansion of the fixed platen 20 and the movable platen 30 is prevented. While reducing, the intensity | strength of the said fixed board 20 and the movable board 30 can be reinforced. In particular, the strength of the thin-walled portion 21b formed by the opening 21 of the fixed platen 20 can be reinforced. The cooling plate 50 in this example is made of martensitic stainless steel (SUS420J2) or the like similar to the mold part. Further, as shown in FIG. 3, a through hole 52 of an appropriate size is formed in the approximate center of the flat portion 51 of the cooling plate 50. When the cooling plate 50 is disposed on the fixed platen 20 side, the locating ring 42 is inserted. In the case where it is arranged on the movable platen 30 side, a drive mechanism such as an ejector or a punch (not shown) can be inserted. In the cooling plate 50, the thickness of the flat surface portion 51 is appropriately set depending on the advanceable position of the nozzle 13 of the injection device 11, and is configured to be 12 mm to 20 mm in this example.

Further, as shown in FIGS. 2 and 3, it is recommended that the cooling plate 50 be formed with a cooling passage 55 through which the coolant flows. And the cooling effect by this cooling plate 50 can be improved by distribute | circulating a cooling fluid in the cooling plate 50 using the well-known chiller (cooling water circulation apparatus) which is not shown in figure. In addition, although the water cooled to about 15 degreeC-20 degreeC with the chiller is used as a cooling liquid, you may use the temperature adjustment water of about 20 degreeC-35 degreeC by a well-known temperature control apparatus. In this figure, reference numeral 56 represents an inflow path of the cooling passage 55, and 57 represents an outflow path of the cooling passage 55.

In addition, the cooling plate 50 is preferably formed with a receiving portion 58 for supporting the fixed mold 41 or the movable mold 46 at the lower portion as shown in the figure . In the cooling plate 50 of the embodiment, the receiving portion 58 is formed to protrude below the flat portion 51 so as to be substantially L-shaped in side view. Since the flat portion 51 is thin as described above, the receiving portion 58 protrudes below the flat portion 51 so that the temperature control device can be operated when connecting the inflow passage 56 and the outflow passage 57 of the cooling passage 55. It becomes easy to do. Further, when the cooling plate 50 is disposed on the movable platen 20 and the fixed platen 30, the receiving portions 58, 58 are arranged to face each other, and the mold portion 40 is placed on the receiving portions 58, 58.

  Here, the attachment of the mold part 40 of the cooling mechanism 10 of the disk injection molding machine will be described. First, the distance between the fixed platen 20 and the movable platen 30 is sufficiently larger than the thickness of the mold part 40. The movable platen 30 is moved backward. Subsequently, the plate-like member P is passed over the tie bars 22C and 22D between the receiving portions 58 and 58 so as to be flush with the receiving portions 58 and 58 of the cooling plate 50, and the mold portion 40 is transferred to the plate-like member. It mounts on P and the receiving parts 58 and 58, and slides from the side of the said cooling mechanism 10 to an attachment position. Then, the locating ring 42 formed on the fixed mold 41 of the mold part 40 is engaged with the hole 21 a of the opening 21 of the fixed platen 20 to advance the movable platen 30, and then the mold unit 40 is appropriately used. Is fixed. Thus, by forming the receiving portion 58 on the cooling plate 50, positioning when the mold portion 40 is disposed on the fixed platen 20 and the movable platen 30 becomes easy.

Further, in the cooling mechanism 10 of the disk for the injection molding machine of the present invention, it is recommended preferable to dispose the heat insulating plate 60 between the mold member 40 and the cooling plate 50. In the example shown in FIGS. 1 and 2, heat insulating plates 60 are attached to the side of the fixed mold 41 that contacts the cooling plate 50 and the side of the movable mold 46 that contacts the cooling plate 50. Further, the heat insulating plate 50 is made of a known member, and is constituted by a plate-like member having a size substantially equal to the mold contact surface of the mold part 40. By disposing the heat insulating plate 60 in this way, heat released from the mold part 40 to the outside can be suppressed, and the cooling effect can be improved .

  Next, the cooling effect by the cooling mechanism 10 of the disk injection molding machine will be described with reference to FIGS. The plot shown in FIG. 4 shows the temperature change (h) for each of the fixed platen 20, the movable platen 30 and the tie bar 22 in the cooling mechanism 10 of the present invention and the fixed platen, the movable platen and the tie bar in the conventional cooling mechanism. ° C). Further, the plot shown in FIG. 5 shows a change in the deviation (μm) of the eccentric position (ECC) of the transfer with respect to the center hole of the disk for each time (h) between the cooling mechanism 10 of the present invention and the conventional cooling mechanism. It is a thing.

As shown in FIG. 4, in the conventional cooling mechanism, each temperature of the fixed platen, the movable platen, and the tie bar increases with time (in the illustrated example, the temperature that was around 25 ° C. at the start is about 3 hours) After that, the temperature rises to about 45-50 ° C.). On the other hand , in the cooling mechanism 10, as shown in FIG. 3, the fixed platen 20 and the movable platen 30 are cooled by the cooling plates 50, 50, thereby suppressing the temperature rise of the fixed platen 20 and the movable platen 30. It can be controlled to a substantially constant temperature regardless of the passage of time. Further, since the temperature of the fixed platen 20 and the movable platen 30 is controlled below the temperature of the tie bar 22, the temperature rise and thermal expansion of the tie bar 22 can be suppressed without providing a separate cooling member or the like on the tie bar 22. .

In this way, the temperatures of the fixed platen 20, the movable platen 30, and the tie bar 22 are controlled to be constant, and the cooling plate 50 is disposed on the fixed platen 20 and the movable platen 30 as described above, so that the fixed platen 20 is disposed. Further, as shown in FIG. 5, the conventional cooling mechanism is accompanied with the temperature rise of the fixed platen, the movable platen, and the tie bar by reducing the positional shift due to the difference in the thermal expansion direction of the movable platen 30 and the thermal expansion of the tie bar 22. While the ECC value tends to increase , the cooling mechanism 10 is controlled to be substantially constant at a low ECC value.

  As described above, in the cooling mechanism 10 of the disk injection molding machine, the cooling having the flat portion 51 larger than the mold portion 49 between the mold portion 40 and the fixed plate 20 and the movable plate 30. By arranging the plates 50, 50, it is possible to suppress a temperature rise during molding of the fixed plate 20, the movable plate 30, and the tie bar 22 without forming a cooling passage in the entire injection molding machine. The strength of the fixed plate 20 and the movable plate 30 can also be reinforced, and the deflection of the fixed plate 20 and the movable plate 30 during mold clamping and injection can be reduced. Accordingly, it is possible to suppress a decrease in molding accuracy due to temperature rise during molding of the fixed platen 20, the movable platen 30, and the tie bar 22 with an extremely simple configuration, and to improve the strength of the fixed platen 20 and the movable platen 30. be able to.

In the cooling mechanism of the disc for an injection molding machine, for example, a stopper is provided at an end portion of one side of the receiving part of the cooling plate, so as to allow regulation of the transverse direction when positioning the mold portions It may be configured.

  Further, in order to more efficiently attach the mold part, a resin plate having a low friction coefficient may be attached to at least one of the lower surface of the mold part or the receiving part of the cooling plate.

Further , although the mold part and the cooling plate are separately formed and arranged, the mold part and the cooling plate may be integrally formed. Further, in the case of integrally forming the cooling plate mold section also may be disposed a heat insulating plate between the mold portion and the cooling plate.

It is a perspective view of the cooling mechanism of the injection molding machine for disks. It is a side view of the cooling mechanism of the injection molding machine for disks of FIG. It is a front view of a cooling plate. It is the plot figure which compared the temperature change of the fixed board of this invention and a prior art, a movable board, and a tie bar. It is the plot figure which compared ECC of this invention and a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cooling mechanism of disk injection molding machine 11 Injection device 12 Heating cylinder 13 Nozzle 15 Mold clamping mechanism 20 Fixed plate 21 Opening 22 Tie bar 30 Movable plate 40 Mold part 41 Fixed die 42 Locating ring 46 Movable die 50 Cooling plate 51 Plane portion 55 Cooling passage 58 Receiving portion 60 Thermal insulation plate

Claims (2)

A cooling mechanism of a disk injection molding machine for injecting and molding a molten resin material from the lateral direction by an injection device,
A fixed plate that is erected in a vertical direction and has an opening into which the injection device can be fitted and inserted in a substantially central portion, and a plurality of tie bars are horizontally arranged vertically;
A movable plate that is disposed opposite to the fixed plate and moves forward and backward with respect to the fixed plate along the plurality of tie bars;
A mold part comprising a fixed mold disposed on the fixed plate and a movable mold disposed on the movable plate;
A cooling liquid circulates between a flat portion that is integrally formed on the fixed plate side of the fixed mold via a heat insulating plate and is disposed between the fixed mold and the fixed plate so as to contact the fixed plate. A stationary platen-side cooling plate having a through hole into which a locating ring can be inserted in the flat portion on the stationary platen side,
A cooling liquid circulates between the movable mold and the movable plate that is integrally formed on the movable platen side through a heat insulating plate and disposed between the movable die and the movable plate so as to contact the movable plate. And a movable platen side cooling plate having a through hole through which a driving mechanism can be inserted in the flat portion on the movable platen side . The cooling mechanism of the disk injection molding machine according to claim 1, wherein each cooling plate is made of martensitic stainless steel and has a thickness of 12 mm to 20 mm .

Images