JP2006150815A - Injection mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mold uniform molded products in respective cavities at the same time without increasing a mold cost, in an injection mold constituted so as to inject and charge a molten material in the cavities respectively formed between at least three mold members in a mold on-off direction to mold the molded products. <P>SOLUTION: The injection mold 11 is composed of the cavity parts 22, 32 and 41 and gate parts 23, 33 and 42 respectively formed to the opposed surfaces 19, 31 and 40 of at least three mold members 13, 15 and 16 provided in the mold on-off direction and the runner parts 24 and 43 respectively individually communicating with the gate parts 23, 33 and 42 and having a main runner R formed thereto linearly. Runner ejection rods 38 are moved within the runner parts 24 and 43 so as to advance and retreat. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an injection mold for molding a molded product by injecting and filling a molten material into cavities formed between at least three mold members provided in the mold opening and closing direction.

  Patent Documents 1 and 2 describe injection molds for molding a molded product by injecting and filling a molten material into cavities formed between at least three mold members provided in the mold opening and closing direction. Is known. In Patent Document 1, a plurality of mold plates that are loosely fitted with vertically long hot sprue bushes are provided, and resin is injected into the cavities between the mold plates that are closed at the time of mold clamping, and then the mold plates are used. A multi-stage injection thin plate molding die is described in which a molded product is taken out at a distance. However, the molding die disclosed in Patent Document 1 has a problem that the molten material may enter the clearance formed between the hot sprue bush and the template, and it is difficult to adjust the clearance. In addition, a mold for molding using a hot sprue bush has a complicated structure, leading to an increase in cost. Further, Patent Document 2 has a problem that the molten material deteriorates when it stays in the hot sprue bush. In particular, in the case of a resin material for a fuel cell separator, there is a problem that carbon and binder may be separated in the hot sprue bush, resulting in non-uniform conductivity of the molded product.

In Patent Document 2, two or more cavities having a direct gate structure are coaxially arranged in series with respect to the inflow direction to the molten plastic resin mold. However, in Patent Document 2, because of the above configuration, there is a large difference in the time for completing the injection filling and the injection filling pressure between the cavity near the injection nozzle and the cavity far from the injection nozzle, and as a result, uniform in each cavity. It was difficult to mold a molded product.
JP-A-60-63120 (Claim 1, FIG. 2) JP 63-104810 A (Claim 1, FIG. 2)

  The present invention has been made in view of the above problems, and is an injection for molding a molded product by injecting and filling molten material into cavities formed between at least three mold members provided in the mold opening and closing direction. An object of the present invention is to provide an injection mold that can form a uniform molded product simultaneously in each cavity without increasing the cost of the mold.

  According to a first aspect of the present invention, there is provided an injection mold in which a molten material is injected and filled into cavities respectively formed between at least three mold members provided in the mold opening and closing direction, thereby molding a molded product. The molding die includes a cavity portion and a gate portion formed on opposite surfaces of the mold member, and a runner portion that is individually connected to the gate portion and has a main runner formed linearly. A runner-projecting rod is moved forward and backward in the interior.

  The injection mold according to claim 2 of the present invention is characterized in that, in claim 1, the runner portion is separated along with the movement of the mold member when the mold is opened, and linearly connected when the mold is clamped. To do.

  The injection mold according to claim 3 of the present invention is the injection mold according to claim 1 or 2, wherein only the main runner is taken out from the material introduction portion of the runner portion by the advancement of the runner projection rod. It is characterized by.

  The injection mold according to claim 4 of the present invention is the injection mold according to claim 1 or 2, wherein only the main runner is inserted from the material introducing portion of the runner portion into the injection device by the advance of the rod for projecting the runner. It is characterized by that.

  The injection mold according to claim 5 of the present invention is the injection mold according to any one of claims 1 to 4, characterized in that the advancement of the runner protruding rod is started during the pressure-holding step. .

  An injection mold according to a sixth aspect of the present invention is the injection mold according to any one of the first to fifth aspects, wherein the second mold member farthest from the first mold member having the material introduction portion is a runner. The standby position of the rod for projecting the runner at the start of injection is farther from the material introduction part by a predetermined distance than the branch part with the gate part of the second mold member inside the runner part of the second mold member. It is a position.

  The injection mold according to the present invention has a cavity portion and a gate portion respectively formed on opposing surfaces of mold members provided at least three or more in the mold opening / closing direction, and communicates with the gate portion individually. The runner part is composed of a runner part in which the main runner is linearly connected, and the runner protrusion rod is moved forward and backward in the runner part, so that it is uniform in each cavity simultaneously without increasing the cost of the mold. A molded product can be formed. Also, in the cold runner injection mold, the runner can be easily taken out.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a partial cross-sectional view of an injection mold according to the present embodiment, and shows a state where a molten material is injected into a cavity. FIG. 2 is a partial cross-sectional view of the injection mold according to this embodiment, and shows a state in which only the main runner is taken out of the mold. FIG. 3 is a partial cross-sectional view of the injection mold according to the present embodiment, showing a state where the mold member is opened and the molded product is taken out. FIG. 4 is a view taken along the line AA in FIG.

  As shown in FIGS. 1 to 3, an injection molding die 11 for molding a fuel cell separator is a first mold member 13 attached to a stationary platen 12 of an injection molding machine and a first die member 13 attached to a movable platen 14. It consists of a two-die member 15 and an intermediate die member 16 sandwiched between the first die member 13 and the second die member 15. In the present invention, the injection mold is composed of at least three mold members, ie, the first mold member, the second mold member, and the intermediate mold member provided in the mold opening / closing direction.

  The first mold member 13 includes a main body portion 17 and a mounting plate 18, and a portion of the mounting plate 18 is fixed to the stationary platen 12 by a bolt or the like (not shown). One side surface of the main body portion 17 is an opposing surface 19 that is matched with the intermediate mold member 16. The other side of the mounting plate 18 is a fixed plate mounting surface, and an injection hole 20 as a material introducing portion is also formed on the fixed plate mounting surface. As shown in FIG. 4, a cavity portion 22 and a gate portion 23 communicating with the cavity portion 22 are formed on the opposing surface 19 of the main body portion 17. In the present embodiment, the gate portion 23 is a film gate that communicates with the upper end surface of the cavity, and the width of the portion connected to the cavity portion 22 is the same as the width of the cavity portion 22 and the width of the gate portion 23. The cavity 22 is formed with a groove and a protrusion corresponding to the fuel cell separator.

  A runner portion 24 is formed in the main body portion 17 and the mounting plate 18 of the first mold member 13 so as to penetrate the main body portion 17 and the mounting plate 18. The runner portion 24 communicates with a portion where the width of the gate portion 23 is narrowed. In addition to the above, a branch runner portion individually connected to the main runner portion may be formed by a groove formed on the opposing surface, and the branch runner portion may be communicated with the gate portion. Further, a bush may be provided on the main body and the mounting plate, and a runner may be formed inside the bush. The runner portion 24 in the present embodiment is for forming a cold runner, and a pipe for a temperature control medium (not shown) for cooling the main runner R and the like is formed around the runner portion 24. Yes. The injection hole 20 is formed on the other side of the runner portion 24 so as to face the other side of the mounting plate 18, and the surface around it is a nozzle touch surface 26. Therefore, when the first mold member 13 is attached to the fixed platen 12, the nozzle 27 of the injection device 21 of the injection molding machine can come into contact with the nozzle touch surface 26 through the hole 25 formed in the fixed platen 12. It has become.

  A pipe for a temperature control medium (not shown) for cooling the molded product P is formed inside the main body portion 17. Similarly, an ejector mechanism (not shown) is disposed in the cavity portion 22 of the main body portion 17. Further, guide rods 28 having a predetermined length are fixed in parallel toward the one side near the four corners of the main body portion 17 of the first mold member 13. As shown in FIG. 3, the length of the guide rod 28 is such that the guide rod 28 does not separate from the second mold member 15 even when the injection mold 11 is opened. Therefore, as shown in FIGS. 1 and 2, the guide rod 28 penetrates the second mold member 15 and the movable platen 14 and further protrudes in one side direction during mold clamping.

  The second mold member 15 is a mold member farthest from the first mold member 13, and includes a main body portion 29 and a mounting plate 30. The portion of the mounting plate 30 of the second mold member 15 is fixed to the movable platen 14 with a bolt or the like (not shown). The other side surface of the main body portion 29 of the second mold member 15 is a facing surface 31 to be mated with the intermediate mold member 16, and one side surface of the mounting plate 30 is a movable plate mounting surface. The facing surface 31 of the main body 29 is substantially flat. A cavity portion 32 constituting a cavity and a gate portion 33 communicating with the cavity portion 32 are formed on the substantially flat surface. The cavity 32 is formed with a groove and a protrusion corresponding to the fuel cell separator. A runner portion 34 is formed in the main body portion 29 so as to penetrate the main body portion 29. The runner portion 34 communicates with a portion where the width of the gate portion 33 is narrowed. A pipe for a temperature control medium (not shown) for cooling the molded product P is formed inside the main body 29. The second mold member 15 has guide holes 39 formed in the vicinity of the four corners through which the guide rods 28 fixed to the first mold member 13 are inserted.

  A through-hole 35 is formed in the mounting plate 30 of the second mold member 15 at the same position as the runner portion 34 (same position in the plane orthogonal to the mold opening / closing direction). In the movable platen 14, a through hole 36 is formed at the same position as the through hole 35 of the mounting plate 30. A hydraulic cylinder 37, which is a runner protruding mechanism, is fixed to the movable plate 14 on the side opposite to the mold. The rod of the hydraulic cylinder 37 can move forward and backward within the movable plate 14 and the through holes 36 and 35 of the mounting plate 30 and the runner portion 34 as a runner protruding rod 38. The runner protrusion mechanism may be provided as a part of the injection mold inside or outside the mold, or may be provided as a part of the injection molding machine attached to the movable platen.

  The intermediate mold member 16 is composed of four mold members having the same shape in the present embodiment, but the number of the intermediate mold members 16 is not limited, and may be 5 to 10 as an example. The intermediate mold member 16 has opposing surfaces 40, 40 on which one side and the other side are mated with any of the other first mold member 13, second mold member 15, and intermediate mold member 16. A cavity portion 41 and a gate portion 42 communicating with the cavity portion 41 are formed on the facing surface 40 of the intermediate mold member 16. The shape of the cavity portion 41 and the like on one side surface of the intermediate mold member 16 is substantially the same as the cavity portion 22 and the like of the first mold member 13 shown in FIG. The shape of the cavity portion 41 and the like on the other side surface of the intermediate mold member 16 is substantially the same as the cavity portion 32 and the like of the second mold member 15. A runner portion 43 is formed in the intermediate mold member 16 so as to penetrate the intermediate mold member 16. The runner portion 43 communicates with a portion where the width of the gate portion 42 is narrowed. The runner portion 43 is for forming a cold runner, and a conduit for a temperature control medium (not shown) for cooling the main runner R and the like is formed around the runner portion 43. In addition, a pipe for a temperature control medium (not shown) for cooling the molded product P is formed inside the intermediate mold member 16. Similarly, an ejector mechanism (not shown) is disposed in the cavity portion 41 of the intermediate mold member 16. Each intermediate mold member 16 is formed with guide holes 44 through which the guide rods 28 fixed to the first mold member 13 are inserted at the same positions near the four corners.

  As shown in FIG. 1, the positions of the runner portions 24, 34, and 43 in the first mold member 13, the second mold member 15, and the intermediate mold member 16 are the same positions (on the plane perpendicular to the mold opening / closing direction). The same position). Therefore, the runner portions 24, 34, and 43 are continuously provided at the time of mold clamping, and the main runner R is linearly formed from the injection hole 20 side that is the material introduction portion to the runner portion 34 of the second mold member 15. It is like that. The runner portions 24, 34, 43 are separated as the mold members 15, 16 are moved when the mold is opened. In addition, when each mold member 13, 15, 16 has a branch runner portion, each branch runner is branched from the main runner formed linearly during injection filling. Link mechanisms 45 that are mold interval adjusting members are disposed on both outer side surfaces of the first mold member 13, the second mold member 15, and the intermediate mold member 16. The link mechanism 45 is bent when the mold is clamped as shown in FIGS. 1 and 2, and is extended when the mold is opened as shown in FIG. 3, so that the distance between the mold members 13, 15, and 16 is kept constant. It has become.

  Next, molding of a fuel cell separator using the injection mold 11 of this embodiment will be described. The resin material used in the present embodiment contains 50% to 90% carbon, contains a thermoplastic resin as a binder, and has poor flowability when melted. First, the mold opening / closing device (including the mold clamping device) of the injection molding machine (not shown) is operated to move the movable platen 14 and the injection molding die 11 is clamped. The mold 11 for injection molding is clamped between the cavity part 22 and the cavity part 41, between the cavity part 32 and the cavity part 41, and between the cavity part 41 and the cavity part 41 of each of the mold members 13, 15, and 16. A cavity is formed in each. Gates are formed between the gate part 23 and the gate part 42, between the gate part 33 and the gate part 42, and between the gate part 42 and the gate part 42, respectively. The main runner R can be linearly formed by the runner portions 24, 34, and 43 formed in contact with and continuous with the mold members 13, 15, and 16.

  The standby position of the runner protrusion rod 38 at the start of injection is the same as the position shown in FIG. 1, and is further inside the runner portion 34 than the branch portion 46 with the gate portion 33 of the second mold member 15. It waits at a position far from the injection hole 20 by a predetermined distance. A cold slug well is formed by the front surface of the runner protruding rod 38 and the recess 47 formed by the runner portion 34. The second mold member may not be provided with a runner portion, but the front surface of the runner protruding rod may be kept on the same plane as the gate portion of the second mold member. In that case, at the time of mold clamping, a runner portion in which the main runner is linearly formed is provided continuously only in the first mold member and the intermediate mold member, and either a cold slug well is not formed or the runner protrudes The front surface of the rod may be concave to form a cold slug well.

  Before and after the injection mold 11 is clamped, the nozzle 27 of the injection device 21 is brought into contact with the nozzle touch surface 26 of the injection mold 11. Then, the screw 49 of the injection device 21 is advanced, and the molten material is injected and filled into the injection mold 11 through the injection hole 20. In this embodiment, high-speed injection is performed at the time of injection filling, and in the injection molding die 11, each gate is individually provided from the main runner R formed by the linear runner portions 24, 34, and 43 having a relatively large diameter. Since each branch is branched, there is almost no time difference between the cavity closest to the injection hole 20 and the cavity farthest from the injection hole 20, and the molten material is injected and filled. In addition, since the direct gate is not employed in the present invention, only the cavity near the nozzle is not filled with the injection filling extremely quickly. If there is still a difference in the time to completion of injection filling between the cavities and the molded product is affected, the sectional area of the gate in each gate part may be changed or the temperature of each gate part may be adjusted individually. Good.

  When the injection process in which the molten material is injected and filled in each cavity is completed, the process proceeds to the pressure holding process. In the present embodiment, during the pressure-holding step, the hydraulic cylinder 37 is operated in parallel with the application of pressure from the injection device 21 side, and the runner protruding rod 38 is advanced in the runner portion 34 (or runner portion 43). Compress the main runner R that has not yet been completely cooled and solidified. The reason for compressing the main runner R by the runner projecting rod 38 is that the runner projecting rod 38 on the side closest to the cavity farthest from the injection hole 20 is advanced and pressure is applied to each cavity, so that each cavity is substantially compressed. This is because the pressure can be applied evenly. On the other hand, during the pressure holding process in a general injection mold, pressure is applied only from the nozzle side, so the cavity farthest from the resin injection hole is more susceptible to pressure loss, and the pressure is evenly distributed to each cavity. It has a problem that it cannot be applied. Then, when the predetermined pressure has elapsed, the pressure holding process is completed, and when the main runner R inside the runner portions 24, 34, 43 provided in series is cooled and solidified, the injection device 21 is changed as shown in FIG. The nozzle 27 is retracted to open the injection hole 20. Next, the hydraulic cylinder 37 is further advanced, and the cooled and solidified main runner R protrudes from the injection hole 20 serving as the material introduction portion toward the injection device 21. Therefore, in this embodiment, the removal process from the mold of the main runner R can be easily performed. In the formation of the separator for the fuel cell, since the plate thickness is thin, the cooling and solidification of the molded product P inside the cavity is performed simultaneously with the cooling and solidification of the main runner R inside the runner portions 24, 34, and 43. Product P completes faster. However, when molding a molded product having a large plate thickness, the runner may be projected when the gate is cooled and solidified even if the molded product is not completely cooled and solidified.

  Next, a mold opening / closing device (not shown) is operated, the movable platen 14 is moved, and the mold 11 for injection molding is opened so that predetermined intervals are formed between the mold members 13, 15, 16. At this time, the intermediate mold member 16 is pulled and moved in the mold opening direction one by one by the link mechanism 45 along with the movement of the movable platen 14. At this time, the intermediate die member 16 is guided and moved by the guide rod 28 disposed on the first die member 13, so that the opposing surfaces 19, 31, 40 of the die members 13, 15, 16 are always parallel. To be kept. When the mold opening is completed, the molded product P in the cavity is released by the ejector mechanism disposed in the first mold member 13 and the intermediate mold member 16. The molded product P which has been released falls to a lower receiving member (not shown) and is carried out to the next process. In addition, since the runner parts 24, 34, and 43 are respectively disposed and divided in the mold members 13, 15, and 16 in the injection mold 11, maintenance work can be easily performed.

  Next, another main runner R processing method shown in FIG. 5 will be described. As shown in FIG. 5, the linear main runner R projecting from the runner portions 24, 34, 43 continuously provided by the runner projecting rod 38 is not projected from the injection hole 20 to the outside. You may make it insert in the injection apparatus 21 from the nozzle hole 48 of the nozzle 27. FIG. In that case, the diameter of the injection hole 20 of the runner portion 24 and the diameter of the nozzle hole 48 of the nozzle 27 are the same or the diameter of the nozzle hole 48 is slightly larger. The heating cylinder front portion of the injection device has a large heater capacity in order to remelt the inserted main runner R. The main runner R is inserted into the injection device 21 before the cooling and solidification of the main runner R in the runner portions 24, 34, and 43 is completed and before the weighing process in the injection device 21 is completed. Is called. By treating the main runner R in this way, the runner R can be recycled without providing a separate runner crushing / refeeding device.

  Moreover, although this embodiment demonstrated the injection mold 11 for the separator for fuel cells which uses a thermoplastic resin material as a binder, it is for injection molding for the separator for fuel cells which uses a thermosetting resin material as a binder. It may be a mold. In this case, each mold member is provided with a heater, and the injection-filled molten material is heated to a predetermined temperature and thermally cured. And the main runner heat-cured in the runner part of the injection mold is taken out by the same procedure as that of either of the above two examples. The material used for molding is not limited to a resin material, and may be a metal material or a ceramic material. The molded product is preferably a thin plate such as a light guide plate or a light diffusing plate, but there is no particular limitation. Not.

  Further, the number of cavities formed between the opposing surfaces of the mold members in the injection mold is not limited to one surface. For example, the film gate portion may be provided on both sides of the runner portion, and the cavity portions may be formed on both sides of the film gate portion. Furthermore, there may be a thin portion radially extending in four directions around the runner portion, and a cavity portion provided continuously with the thin portion. In this case, four cavity portions are formed between the opposing surfaces of the mold members. In the case described above, the runner portions are not in direct contact with each other even during mold clamping. Furthermore, a branch runner portion in which a plurality of tubular runners are formed from the main runner portion may be branched, and two or more cavity portions may be communicated with each branch runner portion via a gate portion.

  Further, the number of runner portions where the main runner of the injection mold is formed is not limited to one, and two or more runner portions may be formed on the injection mold. In that case, all the two or more runner portions may be communicated with each cavity, or only one runner portion may be communicated with each cavity. The number of injection devices may be the same as the number connected to each runner, and is not limited to one. Furthermore, the material introduction part from which the main runner protrudes does not necessarily have to be a resin injection hole formed in the nozzle touch surface. For example, an injection mold in which the space between the manifold block and the first mold member opens at a predetermined interval or more, and the main runner protrudes from the material introduction portion of the runner portion of the first mold member connected to the manifold block. It may be. Moreover, the runner part which forms a main runner may not be divided | segmented into each type | mold member. Further, the main runner may be taken out by being bent or cut in the middle of the protrusion. Furthermore, the injection mold may be a mold for a vertical injection molding machine that is opened and closed in the vertical direction.

  Further, the present invention is not enumerated one by one, but is not limited to that of the above-described embodiment, and it goes without saying that the present invention can be applied to those modified by a person skilled in the art based on the gist of the present invention. That is.

It is a partial cross section figure of the injection mold of this embodiment, Comprising: It is a figure which shows the state by which the molten material was inject | emitted in the cavity. It is a partial cross section figure of the injection mold of this embodiment, Comprising: It is a figure which shows the state from which only the main runner was taken out of the metal mold | die. It is a partial cross section figure of the injection mold of this embodiment, Comprising: It is a figure which shows the state by which the mold member was opened and the molded product was taken out. It is an arrow line view in the AA line in FIG. It is a figure which shows the processing method of another main runner by the injection die of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Injection mold 12 Fixed board 13 1st mold member 14 Movable board 15 2nd mold member 16 Intermediate mold member 17, 29 Main-body part 18, 30 Mounting plate 19, 31, 40 Opposite surface 20 Injection hole 21 Injection apparatus 22 , 32, 41 Cavity part 23, 33, 42 Gate part 24, 34, 43 Runner part 25 Hole 26 Nozzle touch surface 27 Nozzle 28 Guide rod 35, 36 Through hole 37 Hydraulic cylinder 38 Runner protruding rod 39, 44 Guide hole 45 Link mechanism 46 Branching portion 47 Recessed portion 48 Nozzle hole 49 Screw P Molded product R Runner

Claims (6)

In an injection mold for molding a molded product by injecting and filling a molten material into cavities formed between at least three mold members provided in the mold opening and closing direction,
A cavity portion and a gate portion respectively formed on opposing surfaces of the mold member;
Each of the gate portions is individually connected to the runner portion, and the main runner is linearly formed.
An injection mold, wherein a runner protruding rod is moved forward and backward in the runner portion.   The injection mold according to claim 1, wherein the runner portion is separated along with the movement of the mold member when the mold is opened, and is linearly provided when the mold is clamped.   3. The injection mold according to claim 1, wherein only the main runner is taken out from the material introducing portion of the runner portion by the advancement of the rod for projecting the runner.   The injection mold according to claim 1 or 2, wherein only the main runner is inserted into the injection device from the material introducing portion of the runner portion by advancement of the runner protruding rod.   The injection mold according to any one of claims 1 to 4, wherein the advancement of the runner protruding rod is started during a pressure-holding step.   A runner portion is formed in the second die member farthest from the first die member having the material introduction portion, and the standby position of the runner protruding rod at the start of injection is the interior of the runner portion of the second die member. The injection mold according to any one of claims 1 to 5, wherein the mold is further away from the material introduction portion by a predetermined distance than a branch portion with the gate portion of the second mold member.

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