JP2012125925A - Injection molding method and injection molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding method and an injection molding machine capable of molding a resin molding product which is made of a plurality of cavities in different shapes with consistent quality without increasing a clamping force.SOLUTION: The injection molding method using a hot runner system mold which performs injection molding using a mold having a plurality of cavities in different shapes injects a resin material in one desired cavity in such state that a resin passage in communication with the other cavity of the closed molding is closed, supplies the resin material as much as the volume of the next desired cavity to the inside of the injection cylinder in communication with each of the resin passage in such state that the resin passage in communication with one desired cavity, injects the resin material corresponding to the capacity of the desired cavity in such state that the resin passage in communication with the desired cavity is opened, injects the resin material to the plurality of cavities with time differences, and opens the mold after the resin material injected in the plurality of desired cavities is solidified and removes the molding product at the same time.

Description

  The present invention relates to a resin product injection molding method and an injection molding apparatus.

  Conventionally, resin products are processed into a predetermined shape by various molding methods such as extrusion molding, blow molding, and injection molding.

  Among these molding methods, injection molding can be formed in various resin products because it can form a relatively complicated cross-sectional shape.

  This injection molding is known as a processing method in which a heat-melted resin material is injected into a closed mold at a predetermined clamping pressure, cooled and solidified, and the mold is opened and taken out to obtain a desired resin molded product. (For example, refer to Patent Document 1).

JP 2003-039496 A

  However, in the conventional injection molding, since the molten resin material is simultaneously injected into all the plurality of cavities provided in the mold, the sum of the projected areas of the molded products molded in the plurality of cavities becomes large. A large clamping force is required.

  Therefore, a large-sized injection molding machine corresponding to this mold clamping force is required, which increases the installation space for the molding machine and the installation cost of the molding machine. As a result, the manufacturing cost of the resin molded product increases. It was supposed to be done.

  Also, when multiple cavities formed in the mold are of different shapes, if resin material is injected into each cavity at the same time, the pressure applied to each cavity will be different, resulting in non-uniform molded products was there.

  The present invention has been made in view of such circumstances, and is capable of molding a resin molded product having a good quality in a plurality of differently shaped cavities without increasing the clamping force. A method and injection molding machine are provided.

  In order to solve the above-described conventional problems, in the injection molding method according to claim 1, an injection molding method using a hot runner mold that performs injection molding using a mold having a plurality of cavities having different shapes. In the state where the resin flow path leading to the other cavity of the closed mold is closed, the resin material is injected into the desired single cavity, and then the resin flow path leading to the desired single cavity is closed Then, while retreating the piston of the injection cylinder communicating with each resin flow path, the resin material corresponding to the capacity of the next desired cavity is supplied into the injection cylinder via the screw conveyor formed on the piston rod, and then the desired With the resin flow path leading to the cavity open, a resin material corresponding to the desired internal volume of the cavity is supplied from the injection cylinder, and there is a time difference. Performs the supply of the resin material into the plurality of cavities, it was decided to remove simultaneously the mold by opening the mold the molded product after solidification of the resin material injected into the desired plurality of cavities.

  In the injection molding apparatus according to claim 2, a fixed mold and a movable mold are respectively mounted on the fixed side platen and the movable side platen of the injection molding machine, and a plurality of cavities having different shapes are formed by these molds. Forming a plurality of gates for injecting a resin material into a plurality of differently shaped cavities in a fixed mold attached to the fixed side platen, and branching from a connection portion with the nozzle of the injection cylinder A plurality of on-off valves for opening and closing the gates communicating with a plurality of differently shaped cavities with a time difference are provided. When the piston having the screw conveyor function moves backward after the second injection operation, the second injection resin material is supplied into the injection cylinder.

  Further, in the injection molding apparatus according to claim 3, in the injection molding apparatus according to claim 2, the fixed mold includes a mounting plate in which an opening for receiving a resin material injected from an injection cylinder is formed, and the resin A manifold plate having a material flow path formed therein and a cavity plate constituting one side of the cavity, and the open / close valve includes a rod that closes the gate with a sharp tip, and the pressure by the rod The needle valve is composed of an advancing / retreating mechanism for advancing / retreating the rod, and the advancing / retreating mechanism is provided in the manifold plate.

  According to the present invention, it is possible to provide an injection molding method and an injection molding machine capable of molding a resin molded product having a good quality in a plurality of cavities of different shapes without increasing the mold clamping force. .

It is explanatory drawing which showed the structure of the injection molding apparatus in this embodiment. It is explanatory drawing which showed the metal mold | die apparatus of the injection molding apparatus which concerns on this embodiment. It is the flow which showed the flow of the injection molding method which concerns on this embodiment. It is explanatory drawing which showed typically the molding process by the injection molding method which concerns on this embodiment. It is explanatory drawing which showed typically the molding process by the injection molding method which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing the appearance of an injection molding apparatus A in the present embodiment.

  The injection molding apparatus A includes an injection unit 1 that injects a resin material J in a molten state, and a molding unit that receives a molten resin (hereinafter also referred to as a molten resin) in a pressurized mold and molds a resin product. It consists of two.

  An injection cylinder 21 that plasticizes the supplied resin material J by heating is provided inside the injection unit 1, and the injection cylinder 21 has an injection nozzle 23 at the front end. Further, a piston 50 as an injection member is disposed in the injection cylinder 21 so as to be rotatable and movable back and forth.

  The piston 50 is provided with a screw head 50 a at the front end of a piston rod 51 that extends backward in the injection cylinder 21, and a helical screw conveyor 53 is formed on the outer peripheral surface of the piston rod 51. The

  Then, when the metering motor 52 linked to the piston 50 is driven and the piston 50 is rotated, the resin material J is supplied into the injection cylinder 21 from the hopper 20 disposed at the rear portion of the injection cylinder 21. It is advanced along the screw conveyor 53. Along with this, the piston 50 is retracted, and the heated and melted resin is stored in front of the screw head 50a.

  Further, when the injection motor is driven during the injection process and the piston 50 is advanced without rotating, the molten resin stored in front of the screw head 50a is injected from the injection nozzle 23 into the mold part 5 (described later). The resin product is then molded.

  The molding unit 2 includes a mold clamping unit 4 disposed on the base unit 3 and a mold unit 5 that receives the molten resin press-fitted from the injection unit 1 while being pressed by the mold clamping unit 4. ing.

  The mold clamping unit 4 includes a fixed platen 6 erected on the base unit 3 and a toggle support 7 erected at a distance from the fixed platen 6, and between the fixed platen 6 and the toggle support 7. Four tie bars 8 (only two of the tie bars 8 are shown in the figure) are installed as guide members for the movable platen 9.

  The movable platen 9 is configured to be slidable along the tie bars 8 (in the left-right direction in FIG. 1) with the four tie bars 8 inserted therethrough.

  Further, a toggle mechanism 13 for moving the movable platen 9 along the tie bar 8 is interposed between the toggle support 7 and the movable platen 9.

  The toggle mechanism 13 includes a cross head 15 as an advancing / retracting member, a toggle lever 16 supported to be swingable with respect to the cross head 15, a toggle lever 17 supported to be swingable with respect to the toggle support 7, and A toggle arm 18 that is swingably supported with respect to the movable platen 9 is provided, between the crosshead 15 and the toggle lever 16, between the toggle support 7 and the toggle lever 17, and between the movable platen 9 and the toggle arm 18. Between the toggle lever 16 and the toggle lever 17 and between the toggle lever 17 and the toggle arm 18 are linked. In addition, a mold clamping motor 14 as a mold clamping drive unit is attached to substantially the center of the rear end surface (left end surface in the drawing) of the toggle support 7.

  The mold clamping motor 14 is linked to the crosshead 15 described above, and the toggle mechanism 13 can be operated by driving the mold clamping motor 14 and moving the crosshead 15 forward and backward.

  For example, when the toggle mechanism 13 is operated by driving the mold clamping motor 14 in the forward direction and moving the cross head 15 forward (moving in the right direction in the figure), the movable platen 9 is moved forward, and the mold part 5 mold closing can be performed.

  When the mold clamping motor 14 is further driven in the forward direction, the toggle mechanism 13 generates a mold clamping force obtained by multiplying the propulsive force generated by the mold clamping motor 14 by the toggle magnification. Therefore, mold clamping is performed by the mold clamping force, and a cavity space is formed in the mold part 5.

  In this state, when the mold clamping motor 14 is driven in the reverse direction, the cross head 15 is moved backward (moved leftward in the drawing) and the toggle mechanism 13 is operated, the movable platen 9 is moved backward, and the mold Part 5 is opened.

  The mold part 5 includes a fixed mold 10 attached to the fixed platen 6 in a state where a surface constituting the cavity (hereinafter also referred to as a cavity surface) faces the movable platen 9 side, and the cavity surface on the fixed platen 6 side. And a movable mold 11 attached to the movable platen 9 in a state of facing toward.

  Specifically, as shown in FIG. 2, the fixed mold 10 includes a connection port 40 with the injection unit 1, and a fixed side mounting plate 41 for mounting the entire fixed mold 10 to the fixed platen 6. A manifold plate 42 having runners 26 for guiding the injected molten resin to the cavities C1 and C2, and a fixed cavity plate 43 in which the shape of one side surface of the resin product to be molded is formed. ing. In the present embodiment, for ease of explanation, resin molding is performed using two cavities C1 and C2 having different shapes. However, the present invention is not limited to this, and a further cavity is provided. Of course, it may be.

  The fixed side mounting plate 41 is a plate for clamping the manifold plate 42, the ejector plate 45, and the cavity plates 43 and 46 together with the movable side mounting plate 44 described later.

  A connection port 40 to which the injection cylinder 21 of the injection unit 1 is connected is formed at a substantially central portion of the fixed side mounting plate 41, and the tip of the connection port 40 is connected to the runner 26 of the manifold plate 42. It is communicated. That is, the molten resin injected into the connection port 40 by the injection unit 1 is introduced into the runner 26.

  On the stationary side cavity plate 43, runners 26 are formed for guiding the introduced molten resin to the respective cavities. Specifically, the runner 26 includes an inflow runner 27 that receives the molten resin from the injection unit 1, and a first branch runway 28 that branches from the inflow runner 27 and guides the molten resin to the first cavity C1. The second branch runner 29 is branched from the inflow runner 27 and guides the molten resin to the second cavity C2.

  The manifold plate 42 has a built-in heating means for heating the periphery of the runner 26, so-called runnerless mold (hot runner type) that can maintain the molten state of the molten resin flowing in the runner 26. ).

  In addition, on the downstream side of the first branch runner 28 and the second branch runner 29, the first gate valve 30 and the first gate valve 30 that can inject and stop the molten resin independently for each of the cavities C1 and C2. A two-gate valve 31 is provided.

  Each of the gate valves 30 and 31 is provided with a cylindrical body 34 capable of keeping the molten resin flowing inside and maintaining a molten state, and the cavity side end of the cylindrical body 34. An injection opening 35 that injects into C1 and C2 and a sharp rod 37 that is configured to freely advance and retract within the cylindrical body 34 and close the injection opening 35 are provided.

  Further, a rod advancing / retracting mechanism 38 for advancing / retreating the rod 37 disposed in the cylindrical body 34 by hydraulic pressure is provided at an end portion of each rod 37 on the fixed side mounting plate 41 side.

  By driving the rod advancing / retreating mechanism 38, the sharpened rod 37 is moved so that the injection opening 35 can be closed or opened. That is, the gate valves 30 and 31 are so-called needle valves. Each rod advance / retreat mechanism 38 is connected to a hydraulic pipe 38a, and can be driven independently by the pressure of hydraulic oil supplied by a hydraulic supply device (not shown). In FIG. 2, the first gate valve 30 is in an open state (a state in which molten resin can flow into the first cavity C1), and a second gate valve 31 is in a closed state (the molten resin flows into the second cavity C2). Impossible state).

  Further, as described above, the rod advance / retreat mechanism 38 is provided in the manifold plate 42. Therefore, for example, the length of the rod 37 can be shortened as much as possible as compared with the case where the rod advance / retreat mechanism 38 is disposed on the fixed-side mounting plate 41, and a problem due to deformation of the rod 37 can be prevented, The durability of the rod 37 can be improved.

  In the fixed cavity plate 43, a first cavity C1a constituting the first cavity C1 is formed at the position of the injection opening 35 of the first gate valve 30, and the position of the injection opening 35 of the second gate valve 31 is formed. In addition, a second cavity portion C2a constituting the second cavity C2 is formed.

  These cavity portions C1a and C2a are combined with a core portion formed on a movable-side cavity plate 46 described later to form a first cavity C1 and a second cavity C2.

  The cavity portions C1a and C2a are formed with gate ports 36 for allowing the molten resin to flow in through the injection openings 35 of the first gate valve 30 and the second gate valve 31, respectively. That is, the first gate valve 30 and the second gate valve 31 serve as a plurality of on-off valves having a function of opening and closing the gate ports 36 communicating with the plurality of differently shaped cavities with a time difference.

  On the other hand, the movable mold 11 includes a movable side mounting plate 44 for mounting the entire movable mold 11 on the movable platen 9 and a removing mechanism (not shown) for removing the molded resin molded product from the cavities C1 and C2. ) And a movable cavity plate 46 in which the shape of the other side surface of the resin product to be molded is formed.

  The movable side mounting plate 44 is a plate for clamping the manifold plate 42, the ejector plate 45, and the cavity plates 43 and 46 together with the above-described fixed side mounting plate 41.

  The ejector plate 45 is filled with molten resin into the cavities C1 and C2 and solidified, and then is opened from the movable side cavity plate 46 of each resin molded product when the mold is opened to take out the resin molded product. It is the plate provided with the removal mechanism which performs.

  The movable cavity plate 46 is formed with a first core part C1b and a second core part C2b at positions facing the cavity parts C1a and C2a, respectively. A second cavity C2 is formed. In the present embodiment, the projected area of the first cavity C1 has a different shape that is three times the projected area of the second cavity C2.

  The core C1b and C2b of the movable-side cavity plate 46 is exposed to a protruding piece that appears and disappears by the ejector plate 45 removal mechanism described above, and the protruding piece protrudes when the resin molded product is taken out. Thus, the removal assistance of the resin molded product from the movable side cavity plate 46 is performed.

  In the injection molding apparatus A having the above-described configuration, in the injection molding method according to the present embodiment, the resin material J is not injected simultaneously into the plurality of cavities C1 and C2, but sequentially injected while providing a time difference. It has the characteristics. Therefore, an injection molding method according to the present embodiment will be described with reference to FIGS. FIG. 3 is a flow showing the flow of the injection molding method according to the present embodiment, and FIGS. 4 and 5 are explanatory views schematically showing the molding process by the injection molding method according to the present embodiment. Since the flow of FIG. 3 is repeatedly performed, in the following description, the first step S11 to the last step S22 are collectively referred to as “one cycle”, and the next cycle is referred to as “next cycle”. ”, The cycle performed before is expressed as“ previous cycle ”. 4 and 5 show only the mold part 5 and the injection part 1 in a simplified manner for easy explanation.

  In the injection molding method according to the present embodiment, the movable platen 9 is first brought close to the fixed platen 6 by the mold clamping unit 4 to superpose the fixed mold 10 and the movable mold 11 as shown in FIG. The mold is closed (step S11).

  Specifically, the mold clamping motor 14 shown in FIG. 1 is driven in the forward direction, the crosshead 15 is moved forward (moved rightward in FIG. 1), the toggle mechanism 13 is operated, and the movable platen 9 is moved. It advances and the mold part 5 is closed. FIG. 4A shows a state in which the mold closing is not completely completed, and the cavities C1 and C2 are not yet formed by the cavities C1a and C2a and the cores C1b and C2b. . At this time, as shown in FIG. 4A, the injection section 1 is already in a state where the plasticizing step has been performed in the previous cycle.

  Thereafter, pressure is further applied to both molds 10 and 11 by the toggle mechanism 13 (step S12), and cavities C1 and C2 are formed between the fixed mold 10 and the movable mold 11.

  Next, a first cavity injection filling process for injecting the molten resin into the first cavity C1 is performed (step S13). In this step, as shown in FIG. 4B, the injection opening 35 of the first gate valve 30 is opened (hereinafter referred to as the open state), and the injection opening 35 of the second gate valve 31 is closed. (Hereinafter referred to as a closed state) and the piston 50 is advanced in the injection cylinder 21 to fill the inside of the first cavity C1 with the molten resin via the first branch runner 28. In the drawing, the open / closed states of the gate valves 30 and 31 are indicated by shaded open states and closed states by white lines, but this is for ease of understanding. It does not indicate the presence or absence of molten resin in the valves 30 and 31.

  At this time, a force in a direction away from the fixed mold 10 is generated with respect to the movable mold 11 by the molten resin press-fitted into the first cavity C1. Therefore, in order to resist this force, the toggle mechanism 13 applies a force in the direction in which the movable mold 11 is brought close to the fixed mold 10. In the present embodiment, P is the magnitude of the force required at this time.

  Next, a first cavity pressure-holding process is performed to hold the molten resin filled in the first cavity C1 (step S14). In this process, the pressure in the first cavity C1 is maintained by closing the first gate valve 30 that has been opened in step S13.

  Next, as shown in FIG. 4 (c), the second cavity filling plasticization is performed to replenish the injection cylinder 21 with the resin material J which is insufficient for molding in the second cavity C2 by injection into the first cavity C1. A process is performed (step S15). Specifically, a resin material J corresponding to the capacity of the second cavity C <b> 2 is supplied to the hopper 20, and the molten resin is stored in the injection cylinder 21. The gate valves 30 and 31 both have the injection opening 35 closed.

  At this time, the first cavity C1 is filled in the first cavity C1 by circulating a cooling medium (for example, water) through a cooling water passage (not shown) formed in the fixed-side cavity plate 43 and the movable-side cavity plate 46. A first cavity cooling step for cooling and solidifying the resin is performed (step S16).

  Next, a second cavity injection filling process for injecting the molten resin into the second cavity C2 is performed (step S17). In this step, as shown in FIG. 5A, the injection opening 35 of the first gate valve 30 is closed, the second gate valve 31 is opened, and the piston 50 is advanced in the injection cylinder 21. The molten resin is filled into the second cavity C2 through the second branch runner 29.

  At this time, as in the first cavity injection filling step (step S13), the force in the direction away from the fixed mold 10 is applied to the movable mold 11 by the molten resin press-fitted into the second cavity C2. Occurs. Therefore, in order to resist this force, the toggle mechanism 13 applies a force to the movable mold 11 in a direction in which the movable mold 11 is brought close to the fixed mold 10, but the projected area of the second cavity C2 is Since it is 1/3 of the projected area of one cavity C1, the force required at this time is one third of the force required in the first cavity injection filling step, that is, 1 / 3P.

  Accordingly, since the mold clamping pressure required at the time of filling is small, compared with the case where the same mold clamping pressure (P) required in the first cavity injection filling process is applied in the second cavity injection filling process. Thus, the electric power required for the mold clamping motor 14 can be reduced, and the production cost can be reduced.

  Further, as described above, since the first cavity injection filling process and the second cavity injection filling process are performed separately, each cavity C1 is compared with the case where the resin material is simultaneously injected into each cavity C1, C2. , C2 have different shapes, the pressure applied to the cavities C1, C2 can be made constant, so that a uniform molded product can be formed. In addition, each cavity C1, C2 can be set to apply different pressures.

  Furthermore, since the second cavity injection filling process is performed after the first cavity injection filling process, and then the second cavity injection filling process is performed, even with the injection molding apparatus A having a small injection cylinder capacity, A plurality of resin molded products having different shapes can be formed.

  In other words, if the injection cylinder has a capacity capable of filling a maximum capacity cavity among a plurality of differently shaped cavities, a plurality of differently shaped resin molded products can be molded in one cycle.

  Next, a second cavity pressure holding process for holding the molten resin filled in the second cavity C2 is performed (step S18). In this process, the pressure in the second cavity C2 is maintained by closing the second gate valve 31 that has been opened in step S17.

  Next, as shown in FIG. 5B, a first cavity filling plasticizing process is performed in which the resin material J necessary for filling the first cavity C1 is supplied to the injection cylinder 21 in the next cycle (step). S19). Specifically, an amount of resin material J corresponding to the capacity of the first cavity C1 is supplied to the hopper 20, the screw conveyor 53 formed on the piston rod 51 of the injection cylinder 21 is rotated, and the resin material J is heated. The molten resin is fed toward the tip of the injection cylinder 21. At this time, as the molten resin increases at the tip of the injection cylinder 21, the piston 50 gradually moves backward. Note that when this plasticizing step is performed, the gate valves 30 and 31 are both closed.

  At this time, the second cavity C2 is filled in the second cavity C2 by circulating a cooling medium (for example, water) through a cooling water passage (not shown) formed in the fixed cavity plate 43 and the movable cavity plate 46. A second cavity cooling step for cooling and solidifying the resin is performed (step S20).

  Then, the mold clamping motor 14 shown in FIG. 1 is driven in the reverse direction, the crosshead 15 is moved backward (moved leftward in FIG. 1), the toggle mechanism 13 is operated, and the movable platen 9 is moved backward, As shown in FIG. 5C, the mold part 5 is opened (step S21).

  Thereafter, a removal mechanism (not shown) provided on the ejector plate 45 of the movable mold 11 is driven, and the resin molded product 60 formed by the first cavity C1 from the movable mold 11 and the second cavity C2. A removal step of removing the formed resin molded product 61 from the movable mold 11 is performed (step S22). At this time, if it is necessary for the work, the downtime of the injection molding apparatus A can be taken.

  When one cycle is completed in this way, the process returns to step S11 again to start the next cycle, and the resin molded products 60 and 61 are repeatedly manufactured.

  As described above, according to the injection molding method according to the present embodiment, the hot runner mold that performs injection molding using the mold part 5 having a plurality of cavities C1 and C2 having different shapes is used. In the injection molding method, a desired one piece in a state where a resin flow path leading to another cavity (for example, the second cavity C2) of the closed mold part 5 is closed (for example, the second gate valve 31 is closed). The resin material is injected into the cavity (for example, the first cavity C1), and then the resin flow path leading to the desired single cavity (for example, the first cavity C1) is closed (for example, the first gate valve 30 is Screw conveyor 5 formed on piston rod 51 while retreating piston 50 of injection cylinder 21 communicating with each resin flow path (for example, runner 26) in the closed state) The resin material corresponding to the capacity of the next desired cavity (for example, the second cavity C2) is supplied into the injection cylinder 21 through the resin 3, and then the resin flow path leads to the desired cavity (for example, the second cavity C2). In a state where the valve is opened (for example, the second gate valve 31 is opened), a resin material corresponding to the content of a desired cavity (for example, the second cavity C2) is supplied from the injection cylinder 21, and a plurality of cavities are timed. Since the resin material is supplied to C1 and C2, and the resin material injected into the desired plurality of cavities C1 and C2 is solidified, the mold part 5 is opened and the resin molded products 60 and 61 are simultaneously removed from the mold. It is possible to provide an injection molding method capable of molding a resin product with high quality in a plurality of cavities of different shapes without increasing the clamping force. That.

  Further, according to the injection molding apparatus according to the present embodiment, the fixed mold 10 and the movable mold 11 are respectively mounted on the fixed platen 6 and the movable platen 9 of the injection molding machine (for example, the molding unit 2). A plurality of differently shaped cavities (for example, cavities C1 and C2) are formed by the molds 10 and 11, and a plurality of differently shaped cavities (for example, cavity C1) are formed in the fixed mold 10 mounted on the fixed platen 6. , C2) are formed with a plurality of gates (for example, gate ports 36) for injecting the resin material, and further branched from the connection portion of the injection cylinder 21 with the nozzle (injection nozzle 23) to form a plurality of gates (for example, , A resin material flow path (for example, an inflow runner 27, a first branch runway 28, a second branch runway 29) communicating with the gate port 36) and a plurality of differently shaped cavities (examples) For example, a plurality of on-off valves (for example, gate valves 30, 31) for opening and closing the gate (for example, the gate port 36) communicating with the cavities C1, C2) with a time difference are provided. Since the second injection resin material is supplied into the injection cylinder 21 when the piston rod 51 having the screw conveyor 53 function moves backward after the first injection operation, the mold clamping force is increased. Therefore, it is possible to provide an injection molding machine capable of molding a resin product having a good quality with a plurality of cavities having different shapes.

  Furthermore, in the injection molding apparatus according to the present embodiment, the fixed mold 10 has a mounting plate (for example, fixed side mounting) in which a receiving opening (for example, the connection port 40) of a resin material injected from the injection cylinder 21 is formed. Plate 41), a manifold plate 42 in which the resin material flow path (for example, runner 26) is formed, and a cavity plate (for example, fixed side cavity plate 43) that constitutes one side of the cavities C1 and C2. The on-off valve (for example, the gate valves 30, 31) includes a rod 37 that closes the gate (for example, the gate port 36) with a sharpened tip, and the rod by pressure (for example, hydraulic pressure). The needle valve is composed of an advancing / retreating mechanism (for example, a rod advancing / retreating mechanism 38) for advancing / retreating 37, and the advancing / retreating mechanism (for example, a rod) Since the retracting mechanism 38) is provided in the manifold plate 42, the length of the rod 37 is made as short as possible as compared with, for example, the case where the rod advancing / retracting mechanism 38 is disposed on the fixed side mounting plate 41. It is possible to prevent problems caused by deformation of the rod 37 and improve the durability of the rod 37.

  Finally, the description of each embodiment described above is an example of the present invention, and the present invention is not limited to the above-described embodiment. For this reason, it is a matter of course that various modifications can be made in accordance with the design and the like as long as they do not depart from the technical idea according to the present invention other than the embodiments described above.

  For example, in the present embodiment, a mold clamping motor 14 is used as a mold clamping drive unit, but a mold clamping cylinder is used instead of the mold clamping motor 14 as a mold clamping drive unit. The crosshead 15 can be directly advanced and retracted by using the mold and driving the clamping cylinder. Further, in the present embodiment, the mold clamping force is generated by operating the toggle mechanism 13, but the mold clamping or the like is performed by a so-called hydraulic type without using the toggle mechanism 13. You may do it.

  Further, in this embodiment, since there are two cavities formed in the mold part 5, as a rough flow, the first cavity injection filling process → second cavity filling plasticizing process → second cavity injection filling process → first The cavity filling plasticization step → (return) is repeated, but the present invention is not limited to this.

  For example, when three cavities are provided, the first cavity injection filling process → the second cavity filling plasticizing process → the second cavity injection filling process → the third cavity filling plasticizing process → the third cavity injection filling process → Plasticizing process for filling first cavity → Repeating (returning) can similarly obtain a resin molded product.

  Further, the number of cavities to be filled in each cavity injection filling process is not necessarily one. For example, two cavities (second cavity and third cavity) having a capacity smaller than half the capacity of the first cavity in the first cavity injection filling process and filling the first cavity in the second cavity injection filling process. You may make it fill with. At this time, it is more preferable that the second cavity and the third cavity have the same shape or the same projected area.

  In this embodiment, the rod advance / retreat mechanism 38 is configured to advance and retract the rod 37 with the pressure of hydraulic oil supplied by a hydraulic supply device (not shown). For example, the rod advance / retreat mechanism 38 is configured to advance and retract the rod 37 with air pressure. May be.

  In the present embodiment, the pressure supply to the rod advance / retreat mechanism 38 is performed via the connection member 38b provided on the manifold plate 42. However, the present invention is not limited to this. For example, the connection member 38b Alternatively, the fixed side mounting plate 41 may be provided.

  In the present embodiment, one resin molded product (for example, the resin molded product 60) is formed from one cavity (for example, the cavity C1). However, the present invention is not limited to this. A plurality of smaller cavities may be formed in one cavity, and a plurality of resin molded products may be obtained.

DESCRIPTION OF SYMBOLS 1 Injection part 2 Molding part 4 Mold clamping part 5 Mold part 6 Fixed platen 9 Movable platen 10 Fixed mold 11 Movable mold 13 Toggle mechanism 21 Injection cylinder 23 Injection nozzle 26 Runway 30 1st gate valve 31 2nd gate valve 35 Injection opening 37 Rod 38 Rod advance / retreat mechanism 38a Hydraulic piping 40 Connection port 41 Fixed side mounting plate 42 Manifold plate 43 Fixed side cavity plate 50 Piston 51 Piston rod 53 Screw conveyor A Injection molding device C1 1st cavity C2 2nd cavity J Resin material

Claims (3)

In an injection molding method using a hot runner mold that performs injection molding using a mold having a plurality of cavities made of different shapes,
With the resin flow path leading to the other cavity of the closed mold closed, the resin material is injected into a desired single cavity, and then the resin flow path leading to the desired single cavity closed. While retreating the piston of the injection cylinder communicated with each resin flow path, a resin material corresponding to the capacity of the next desired cavity is supplied into the injection cylinder through a screw conveyor formed on the piston rod,
Next, in a state where the resin flow path leading to the desired cavity is opened, a resin material corresponding to the content of the desired cavity is supplied from the injection cylinder, and the resin material is supplied to a plurality of cavities with a time difference,
An injection molding method comprising: opening a mold after solidifying a resin material injected into a plurality of desired cavities and simultaneously removing a molded product.   A fixed mold and a movable mold are mounted on the fixed side platen and the movable side platen of the injection molding machine, respectively, and a plurality of cavities of different shapes are formed by these molds, and the fixed mounted on the fixed side platen. A plurality of gates for injecting a resin material into a plurality of differently shaped cavities are formed in the mold, and a resin material flow path that branches from a connection portion with the nozzle of the injection cylinder and communicates with the plurality of gates. And a plurality of on-off valves for opening and closing the gates connected to a plurality of differently shaped cavities with a time difference from each other, and the injection cylinder is a piston having a screw conveyor function after the first injection operation An injection molding apparatus characterized in that the second injection resin material is supplied into the injection cylinder when the cylinder moves backward.   The fixed mold includes a mounting plate in which an opening for receiving a resin material injected from an injection cylinder is formed, a manifold plate in which the resin material flow path is formed, and a cavity plate that constitutes one side of the cavity. The open / close valve is a needle valve comprising a rod that closes the gate with a sharp tip and an advance / retreat mechanism that advances and retracts the rod by pressure, and the advance / retreat mechanism is provided in the manifold plate. The injection molding apparatus according to claim 2, wherein

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