Injection molding machine and injection molding method

Abstract

The present invention provides an injection molding machine capable of appropriately changing the position of a supply hole for resin raw material in a cylinder. The injection molding machine according to the present invention includes a supply hole formed in a side wall portion of a cylinder to supply resin raw material to the inside of the cylinder, and a closing portion that closes the supply hole in conjunction with movement of a torpedo-shaped piston to the other end portion side of the cylinder when the torpedo-shaped piston moves to plasticize the resin raw material.

Description

TECHNICAL FIELD

[0001] The present application relates to an injection molding machine and an injection molding method. BACKGROUND

[0002] Japanese Patent Application Publication No. 2017-132039 discloses an injection molding machine that includes a cylinder that forms an injection port at a front end portion, a hopper that is connected to the cylinder, a torpedo-shaped piston that moves within the cylinder and has an end portion of a rod fixed, and a plunger that is disposed on the open port side of the cylinder and allows the rod to pass through.

[0003] In a case where such an injection molding machine is used to inject a molten resin, first, the plunger is moved to the opposite side with respect to the injection port side of the cylinder in a state where the plunger is fixed to the rod, and the connection port of the cylinder and the hopper (i.e., a supply hole of a resin raw material) is opened, and a resin raw material is supplied from the supply hole to a space on the plunger side with respect to the torpedo-shaped piston within the cylinder.

[0004] Next, the fixed state of the plunger and the rod is released, and the plunger is moved to the injection port side of the cylinder, and the torpedo-shaped piston is moved within the cylinder to the opposite side with respect to the injection port side of the cylinder via the rod in a state where the supply hole of the cylinder is closed by the plunger and the open port of the cylinder is closed.

[0005] At this time, the resin raw material passes through the groove portion of the torpedo-shaped piston, and the resin raw material is plasticized to become a molten resin, and the molten resin flows into the space on the injection port side of the torpedo-shaped piston within the cylinder. Then, the torpedo-shaped piston is moved to the injection port side of the cylinder, and the molten resin is injected from the injection port. SUMMARY

[0006] The present application applicant has found the following problem. The injection molding machine of Japanese Patent Application Publication No. 2017-132039 is configured to block the supply hole of the cylinder by the plunger. In such a configuration, for example, in a case where the position of the supply hole is changed to the injection port side, the amount of protrusion of the plunger toward the inside of the torpedo-shaped piston within the cylinder becomes large. Therefore, in the injection molding machine of Japanese Patent Application Publication No. 2017-132039, it is not realistic to appropriately change the position of the supply hole of the resin raw material.

[0007] The present application is completed in view of such a problem point, and achieves an injection molding machine and an injection molding method that can appropriately change the position of a supply hole of a resin raw material in a cylinder.

[0008] An injection molding machine according to an aspect includes:

[0009] a cylinder that accommodates a resin raw material;

[0010] a torpedo-shaped piston that plasticizes the aforementioned resin raw material by moving inside the aforementioned cylinder to thereby form a molten resin and extrudes the aforementioned molten resin; and

[0011] an injection portion that is provided at one end portion of the aforementioned cylinder and injects the aforementioned molten resin,

[0012] The aforementioned injection molding machine further includes:

[0013] a supply hole that is formed in a side wall portion of the aforementioned cylinder and supplies the aforementioned resin raw material to the inside of the aforementioned cylinder; and

[0014] a closing portion that closes the aforementioned supply hole in conjunction with the movement of the aforementioned torpedo-shaped piston when the aforementioned torpedo-shaped piston moves to the other end portion side of the aforementioned cylinder in order to plasticize the aforementioned resin raw material.

[0015] In the aforementioned injection molding machine, it is preferable that the aforementioned closing portion plug the aforementioned supply hole in such a manner that softened aforementioned resin raw material or the aforementioned molten resin does not flow back from the aforementioned supply hole.

[0016] In the aforementioned injection molding machine, it is preferable that the aforementioned supply hole be provided at a position that satisfies (St - x) / St ≤ γ,

[0017] where St is the stroke amount from the bottom dead center to the top dead center of the aforementioned torpedo-shaped piston, γ is the fill rate of the aforementioned resin raw material that is set in advance, and x is the distance from the other end portion of the aforementioned cylinder to the center position of the aforementioned supply hole.

[0018] In the aforementioned injection molding machine, it is preferable that the aforementioned closing portion be formed in the side surface of the aforementioned torpedo-shaped piston.

[0019] In the aforementioned injection molding machine, it is preferable that the aforementioned closing portion be provided at the other end portion side of the aforementioned cylinder with respect to the aforementioned torpedo-shaped piston.

[0020] In the aforementioned injection molding machine, it is preferable that the other end portion of the aforementioned cylinder be open,

[0021] a plunger that presses the aforementioned resin raw material supplied to the inside of the aforementioned cylinder via the other end portion of the aforementioned cylinder.

[0022] The aforementioned injection molding machine preferably includes:

[0023] an exhaust hole that communicates the space on the other end portion side of the aforementioned cylinder with respect to the aforementioned torpedo-shaped piston with the outside of the aforementioned cylinder; and

[0024] an insertion portion that is in conjunction with the movement of the aforementioned torpedo-shaped piston and plugs the aforementioned exhaust hole when the aforementioned supply hole is closed by the aforementioned closing portion.

[0025] In the above injection molding machine, it is preferable that the aforementioned resin raw material be a material having a lower glass transition point relative to polycarbonate.

[0026] In the above injection molding machine, it is preferable that the aforementioned resin raw material be a material having a higher glass transition point relative to polypropylene.

[0027] The injection molding method according to one embodiment of the present application is an injection molding method in which a torpedo-shaped piston is moved inside a cylinder, a resin raw material is plasticized, a molten resin is formed, and the molten resin is injected,

[0028] When the aforementioned resin raw material is plasticized, the aforementioned supply hole of the resin raw material formed in the side wall portion of the cylinder is closed by a closing portion that moves in conjunction with the movement of the aforementioned torpedo-shaped piston.

[0029] In the above injection molding method, it is preferable that the aforementioned closing portion plug the aforementioned supply hole in such a manner that softened resin raw material or the aforementioned molten resin does not flow backward from the supply hole.

[0030] According to the present application, an injection molding machine and an injection molding method that can appropriately change the position of a supply hole of a resin raw material in a cylinder can be realized.

[0031] The above and other objects, features and advantages of the present application will become more fully understood from the following detailed description and appended claims taken in conjunction with the accompanying drawings, which are shown by way of illustration only, and thus are not to be considered as limiting the present application. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a cross-sectional view schematically showing an injection molding machine according to Embodiment 1.

[0033] Figure 2 is a cross-sectional view of II-II of Figure 1

[0034] Figure 3 is an exploded view showing a piston in the injection molding machine according to Embodiment 1.

[0035] Figure 4 is a perspective view showing a torpedo-shaped piston in the injection molding machine according to Embodiment 1.

[0036] Figure 5 is a view showing the torpedo-shaped piston in the injection molding machine according to Embodiment 1, as viewed from the Z-axis + side.

[0037] Figure 6 is a cross-sectional view showing an operation for plasticizing a resin raw material in the injection molding machine according to Embodiment 1.

[0038] ​Figure 7 is a sectional view showing an operation for plasticizing a resin material in the injection molding machine of Embodiment 1.

[0039] Figure 8 is a sectional view schematically showing the injection molding machine of Embodiment 2.

[0040] Figure 9 is a sectional view schematically showing the injection molding machine of Embodiment 3.

[0041] Figure 10 is a perspective view showing a rod, a piston, and a closure portion in the injection molding machine of Embodiment 3.

[0042] Figure 11 is a perspective view showing a periphery of the closure portion in the injection molding machine of Embodiment 3.

[0043] Figure 12 is a perspective view showing the closure portion in the injection molding machine of Embodiment 3.

[0044] Figure 13 is a sectional view showing an operation for plasticizing a resin material in the injection molding machine of Embodiment 3.

[0045] Figure 14 is a sectional view showing an operation for plasticizing a resin material in the injection molding machine of Embodiment 3.

[0046] Figure 15 is a partial sectional view schematically showing the injection molding machine of Embodiment 4.

[0047] Figure 16 is a different partial sectional view schematically showing the injection molding machine of Embodiment 4.

[0048] Figure 17 is a perspective view showing a closure portion in the injection molding machine of Embodiment 4. DETAILED DESCRIPTION

[0049] Hereinafter, a specific embodiment to which the present application is applied will be described in detail with reference to the drawings. However, the present application is not limited to the following embodiment. In addition, the following description and drawings are appropriately simplified for clear description.

[0050] <Embodiment 1>

[0051] First, the structure of the injection molding machine of the present embodiment will be described. With regard to the injection molding machine of the present embodiment, it is preferable, for example, when a work is layered molded using a resin material having a lower glass transition point than ABS, polycarbonate (PC), or the like (such as polypropylene (PP), polyamide (PA), or the like).

[0052] Figure 1 is a cross-sectional view schematically showing the injection molding machine of the present embodiment, showing a state in which a resin raw material is supplied to the inside of the cylinder. Figure 2 is Figure 1 II-II cross-sectional view. Also, in the following description, for the sake of clear description, description is made using a three-dimensional (XYZ) coordinate system. Here, in Figure 1 and the like, the resin raw material supplied to the inside of the cylinder is schematically shown.

[0053] As shown in Figure 1 , the injection molding machine 1 is provided with a cylinder 11, an injection portion 12, a piston 13, a first heating portion 14, and a second heating portion 15. The cylinder 11 extends in the Z-axis direction, and has a top cylinder shape in which the end portion on the Z-axis + side is closed.

[0054] That is, the cylinder 11 is provided with a closed portion 11a disposed on the Z-axis + side, and a cylindrical side wall portion 11b continuous with the peripheral portion of the closed portion 11a and extending from the closed portion 11a toward the Z-axis - side, and the end portion of the cylinder 11 on the Z-axis - side is open. At this time, the surface on the Z-axis - side of the closed portion 11a of the cylinder 11 can be an inclined surface inclined toward the Z-axis - side as it goes from the center of the cylinder 11 toward the peripheral portion.

[0055] In the closed portion 11a of the cylinder 11, a through hole 11c is formed that penetrates the closed portion 11a in the Z-axis direction. In the side wall portion 11b of the cylinder 11, a supply hole 11d is formed, and a hopper that houses a resin raw material M is connected to the supply hole 11d.

[0056] Here, the configuration of the supply hole 11d is described later. In the end portion on the Z-axis - side in the side wall portion 11b of the cylinder 11, a flange portion 11e is formed that protrudes to the radial direction outside of the cylinder 11.

[0057] The injection portion 12 is disposed on the Z-axis - side with respect to the cylinder 11 in a manner that enables injection of the molten resin extruded from the cylinder 11. The injection portion 12 has an injection port 12a that injects the molten resin, and a communication path 12b that guides the molten resin to the injection port 12a.

[0058] Such an injection portion 12 is fixed to the flange portion 11e of the cylinder 11 via a lock nut 16. At this time, as shown in Figure 1 , the end portion on the Z-axis + side of the communication path 12b is in communication with the inside of the cylinder 11.

[0059] Here, the injection portion 12 is divided into a first plate 12c that forms the injection port 12a, and a second plate 12d that forms the communication path 12b, and the detailed functions are described later, but the second plate 12d can also be composed of a material excellent in heat conductivity such as a ceramic plate.

[0060] The piston 13 is disposed inside the cylinder 11 in a manner so as to be movable inside the cylinder 11. Figure 3 is an exploded view showing the piston in the injection molding machine of the present embodiment. Figure 4 is a perspective view showing the torpedo-shaped piston in the injection molding machine of the present embodiment. Figure 5 is a view showing the torpedo-shaped piston in the injection molding machine of the present embodiment as viewed from the Z-axis + side.

[0061] As shown in Figure 3 , the piston 13 is provided with a torpedo-shaped piston 13a, a check ring 13b, a stopper 13c, a pressurizing piston 13d, and a force applying member 13e. The torpedo-shaped piston 13a has a roughly equal outer peripheral shape to the inner peripheral shape of the cylinder 11 as a basic form based on a top-closed cylindrical shape with the end portion on the Z-axis + side being closed.

[0062] That is, the torpedo-shaped piston 13a is provided with a closed portion 13f disposed on the Z-axis + side, and a cylindrical side wall portion 13g continuous with the peripheral portion of the closed portion 13f and extending from the closed portion 13f toward the Z-axis - side, and the end portion on the Z-axis - side of the torpedo-shaped piston 13a is open.

[0063] As shown in Figure 4 , in the closed portion 13f of the torpedo-shaped piston 13a, a through-hole 13h is formed which penetrates the closed portion 13f in the Z-axis direction. At this time, with respect to the surface on the Z-axis + side of the closed portion 13f, an inclined surface is provided which inclines toward the Z-axis - side as it goes from the center toward the peripheral portion of the torpedo-shaped piston 13a in a manner corresponding to the shape of the surface on the Z-axis - side of the closed portion 11a of the cylinder 11.

[0064] As shown in Figures 3 to 5 , in the side wall portion 13g of the torpedo-shaped piston 13a, a closing portion 13i and a groove portion 13j are formed. The closing portion 13i closes the supply hole 11d of the cylinder 11 during a prescribed range in the Z-axis direction in which the piston 13 is disposed inside the cylinder 11.

[0065] As shown in Figure 2 , as viewed in the Z-axis direction, the closing portion 13i is disposed in the region of the side wall portion 13g of the torpedo-shaped piston 13a corresponding to the supply hole 11d of the cylinder 11. Also, the outer peripheral shape (i.e., the side surface) of the closing portion 13i corresponds to the inner peripheral shape (i.e., the side surface) of the cylinder 11. Such a closing portion 13i extends in the Z-axis direction, and for example, can be disposed in substantially the entire region in the Z-axis direction of the side wall portion 13g of the torpedo-shaped piston 13a.

[0066] The groove portion 13j extends in the Z-axis direction and is disposed at substantially equal intervals in the peripheral direction of the torpedo-shaped piston 13a in a region other than the region in which the closing portion 13i is formed in the side wall portion 13g of the torpedo-shaped piston 13a.

[0067] However, as described later, as long as the groove portion 13j is shaped and arranged so that the resin raw material M supplied to the first space S1 (see FIG. 2) on the Z-axis + side of the piston 13 in the cylinder 11 passes through the groove portion 13j, the resin raw material M can be plasticized to become a molten resin, and the molten resin can flow into the second space S2 on the Z-axis - side of the piston 13 in the cylinder 11. Figure 1 ) passes through the groove portion 13j, the resin raw material M can be plasticized to become a molten resin, and the molten resin can flow into the second space S2 on the Z-axis - side of the piston 13 in the cylinder 11.

[0068] As shown in FIG. 3, the check ring 13b is annular in shape and has an outer peripheral shape that is substantially equal to the inner peripheral shape of the cylinder 11. Also, the width dimension of the check ring 13b in the radial direction has a length that is greater than the depth of the groove portion 13j. Such a check ring 13b is arranged on the Z-axis - side of the torpedo-shaped piston 13a. Figure 3 The stopper 13c holds the check ring 13b at the end portion on the Z-axis - side of the torpedo-shaped piston 13a. In detail, the stopper 13c has a ring portion 13k and a hook portion 13l, as shown in FIG. 4, for example.

[0069] Figure 3 The ring portion 13k has an outer peripheral shape that is substantially equal to the inner peripheral shape of the torpedo-shaped piston 13a. The hook portion 13l is substantially L-shaped when viewed from a direction orthogonal to the Z-axis, and the end portion on the Z-axis + side of the vertical portion of the hook portion 13l is fixed to the ring portion 13k.

[0070] The ring portion 13k has an outer peripheral shape that is substantially equal to the inner peripheral shape of the torpedo-shaped piston 13a. The hook portion 13l is substantially L-shaped when viewed from a direction orthogonal to the Z-axis, and the end portion on the Z-axis + side of the vertical portion of the hook portion 13l is fixed to the ring portion 13k.

[0071] As shown in FIG. 5, the horizontal portion of the hook portion 13l protrudes outward from the ring portion 13k from the end portion on the Z-axis - side of the vertical portion of the hook portion 13l. The hook portions 13l are arranged at substantially equal intervals in the circumferential direction of the ring portion 13k. Figure 3 In a state in which the through hole of the check ring 13b passes through the vertical portion of the ring portion 13k and the hook portion 13l, the ring portion 13k is fitted to the open mouth of the end portion on the Z-axis - side of the torpedo-shaped piston 13a. Thus, the check ring 13b is held at the end portion on the Z-axis - side of the torpedo-shaped piston 13a via the stopper 13c.

[0072] At this time, the length of the vertical portion of the hook portion 13l in the Z-axis direction is longer than the thickness of the check ring 13b in the Z-axis direction. Thus, the check ring 13b can move in the Z-axis direction between the end portion on the Z-axis - side of the cylinder 11 and the horizontal portion of the hook portion 13l. However, the stopper 13c is a structure that can hold the check ring 13b so as to be movable in the Z-axis direction at the end portion on the Z-axis - side of the cylinder 11.

[0073] As shown in FIG. 6, the check ring 13b is held at the end portion on the Z-axis - side of the torpedo-shaped piston 13a via the stopper 13c.

[0074] Figure 3 ​​As shown, the pressurizing piston 13d is a bottomed cylindrical shape in which the Z-axis-side end portion of the pressurizing piston 13d is closed, for example, the Z-axis-side end surface of the pressurizing piston 13d is a substantially flat surface parallel to the XY plane. Also, the outer peripheral shape of the pressurizing piston 13d is substantially equal to the inner peripheral shape of the torpedo-shaped piston 13a.

[0075] The pressurizing piston 13d is movably inserted into the inside of the torpedo-shaped piston 13a in a state in which the pressurizing piston 13d is plugged by the sealing member 13m between the torpedo-shaped piston 13a and the pressurizing piston 13d. Therefore, by moving the pressurizing piston 13d relative to the torpedo-shaped piston 13a in the Z-axis direction, the amount of protrusion of the torpedo-shaped piston 13a toward the second space S2 is changed.

[0076] At this time, the detailed function will be described later, but as Figure 3 shown, an intrusion portion 13n in which molten resin intrudes can also be formed on the Z-axis-side end surface of the pressurizing piston 13d. The intrusion portion 13n is, for example, a groove portion formed on the Z-axis-side end surface of the pressurizing piston 13d, which extends in a direction orthogonal to the Z-axis.

[0077] However, the intrusion portion 13n is only a shape that enables molten resin to intrude between the Z-axis-side end surface of the pressurizing piston 13d and the Z-axis+side end portion of the injection portion 12 in a state in which the Z-axis-side end surface of the pressurizing piston 13d is in contact with the Z-axis+side end portion of the injection portion 12.

[0078] The urging member 13e urges the pressurizing piston 13d relative to the torpedo-shaped piston 13a toward the second space S2 side of the cylinder 11. The urging member 13e is, for example, an elastic member such as a coil spring, as Figure 3 shown.

[0079] The urging member 13e is disposed inside the pressurizing piston 13d, the Z-axis+side end portion of the urging member 13e is in contact with the Z-axis+side end portion of the torpedo-shaped piston 13a, and the Z-axis-side end portion of the urging member 13e is in contact with the Z-axis-side end portion of the pressurizing piston 13d.

[0080] At the Z-axis+side end portion of such a piston 13, as Figure 1 shown, the Z-axis-side end portion of the rod 17 is connected. On the rod 17, a through-hole 17a that penetrates the rod 17 in the Z-axis direction is formed, and the through-hole 13h of the torpedo-shaped piston 13a communicates with the through-hole 17a of the rod 17.

[0081] The rod 17 is a structural component of a drive device for driving the piston 13, and passes through the through-hole 11c of the cylinder 11. Also, the rod 17 is connected to, for example, a slider of a ball screw that is a structural component of the drive device, and moves in the Z-axis direction via the slider by rotating a threaded shaft of the ball screw by a motor. However, the means for moving the rod 17 in the Z-axis direction is not limited.

[0082] The first heating portion 14 has, for example, a heater or the like, and is wound around a Z-axis-side portion of the side wall portion 11b of the cylinder 11. However, the first heating portion 14 is only required to be a structure that can heat the resin material inside the cylinder 11 and that can keep the molten resin warm.

[0083] The second heating portion 15 has, for example, a heating wire or the like, and is provided on the second plate 12d of the injection portion 12. However, the second heating portion 15 is only required to be a structure that can heat the molten resin injected from the injection portion 12 to a temperature within a range set in advance.

[0084] Next, the position in the Z-axis direction of the supply hole 11d of the cylinder 11 in the injection molding machine 1 of the present embodiment will be described. The supply hole 11d of the cylinder 11 is disposed at a position that can be closed by the closing portion 13i of the piston 13 in such a manner that softened resin (resin that has become an elastomer or a semi-molten body, for example), molten resin does not flow backward from the supply hole 11d of the cylinder 11 when the resin material M is plasticized in the first space S1 of the cylinder 11.

[0085] For example, the supply hole 11d of the cylinder 11 can be disposed at a position in the Z-axis direction of the cylinder 11 that satisfies the following <Equation 1>.

[0086] <Equation 1> (St - x) / St ≤ γ

[0087] where St is the stroke amount from the position at which the torpedo-shaped piston 13a is disposed at the most Z-axis- side (i.e., the bottom dead center) to the position at which the torpedo-shaped piston 13a is disposed at the most Z-axis+ side (i.e., the top dead center), γ is a fill rate of the resin material M that is set in advance, and x is the distance from the Z-axis- side end of the closing portion 11a of the cylinder 11 to the center position of the supply hole 11d.

[0088] At this time, the fill rate γ can be set, for example, in accordance with the volume of the first space S1 of the cylinder 11 in a state in which the piston 13 is disposed at the most Z-axis- side, and the volume of the resin material M supplied to the first space S1 of the cylinder 11 in this state.

[0089] For example, in a case where polypropylene, polyamide, or the like is used as the resin material M, and the filling rate γ is set to 0.5 (i.e., 50%), when the position of the piston 13 in the Z-axis direction reaches a position at which the stroke amount St of the piston 13 is halved, the resin material M is compressed by the piston 13 and starts to soften by the heating of the first heating portion 14, and thus the supply hole lid is provided at a position below the half of the stroke amount of the piston 13 toward the + side of the Z-axis.

[0090] Thus, the supply hole lid is closed by the closing portion 13i of the torpedo-shaped piston 13a before the piston 13 moves to the + side of the Z-axis and the filling rate of the resin material M becomes 1 (i.e., 100%). Thus, the backflow of the softened resin from the supply hole lid of the cylinder 11 can be suppressed.

[0091] Next, the flow of molding a workpiece using the injection molding machine 1 of the present embodiment will be described. Figure 6 and Figure 7 is a sectional view showing the operation for plasticizing the resin material in the injection molding machine of the present embodiment. First, the piston 13 is disposed at the most + side of the Z-axis, and the piston 13 is moved to the - side of the Z-axis via the rod 17, and at the same time, the granular resin material M is supplied from the supply hole lid lid of the cylinder 11 to the first space S1 of the cylinder 11.

[0092] Then, as shown in Figure 1 , when the piston 13 reaches the most - side of the Z-axis, the supply of the resin material M is stopped. At this time, the resin material M is supplied to the first space S1 of the cylinder 11 at the above-described filling rate γ. In addition, the pressurizing piston 13d of the piston 13 is in a state of being pressed into the inside of the torpedo-shaped piston 13a in contact with the injection portion 12, and at the same time, the force applying member 13e is in a compressed state.

[0093] Next, the piston 13 is moved to the + side of the Z-axis via the rod 17. At this time, in a state where the filling rate of the resin material M in the first space S1 reaches 100%, the resin material M is compressed by the piston 13, the closing portion 11a of the cylinder 11, and the side wall portion lib of the cylinder 11, and is softened by the heating of the first heating portion 14.

[0094] Then, in a state where the filling rate of the resin material M in the first space S1 reaches 100%, as shown in Figure 6 , the closing portion 13i of the piston 13 reaches the supply hole lid lid of the cylinder 11, and the closing portion 13i closes the supply hole lid lid. Thus, the backflow of the softened resin from the supply hole lid lid can be suppressed.

[0095] When the resin material M in the first space S1 reaches 100% of the filling rate, as the piston 13 further moves to the Z-axis + side, the resin material M passes through the groove portion 13j of the piston 13, and at the same time, is plasticized to become a molten resin, and flows into the second space S2 of the cylinder 11.

[0096] At this time, the check ring 13b of the piston 13 is pushed to the Z-axis - side, and via the gap between the Z-axis - side end of the torpedo-shaped piston 13a and the check ring 13b, the molten resin can be made to flow well from the through hole of the check ring 13b into the second space S2 of the cylinder 11.

[0097] Further, in the case where the Z-axis + side surface of the torpedo-shaped piston 13a of the piston 13 is formed as an inclined surface that inclines to the Z-axis - side as it goes from the center of the torpedo-shaped piston 13a toward the peripheral portion, when the piston 13 moves to the Z-axis + side, the resin material M can be guided well to the groove portion 13j of the torpedo-shaped piston 13a of the piston 13.

[0098] Here, as the piston 13 moves to the Z-axis + side, the pressurizing piston 13d protrudes from the torpedo-shaped piston 13a under the action of the urging of the urging member 13e. At this time, the shape of the pressurizing piston 13d, the urging of the urging member 13e, and the like can be set in such a way that as the piston 13 moves to the Z-axis + side, the amount of decrease in the volume of the first space S1 of the cylinder 11 becomes more than the amount of increase in the volume of the second space S2. Thereby, when the piston 13 moves to the Z-axis + side, the inflow of gas into the second space S2 of the cylinder 11 can be suppressed.

[0099] Next, as shown in FIG. 6, when the piston 13 reaches the most Z-axis + side, the piston 13 is moved to the Z-axis - side via the rod 17. Thereby, the molten resin R is pressed in by the piston 13, and the molten resin R is injected via the communication path 12b and the injection port 12a of the injection portion 12. Figure 7

[0100] Here, as the piston 13 moves to the Z-axis - side, the pressure of the second space S2 of the cylinder 11 rises, the molten resin R intrudes into the intrusion portion 13n of the pressurizing piston 13d, and the pressurizing piston 13d moves to the Z-axis + side, and is pressed into the inside of the torpedo-shaped piston 13a.

[0101] At this time, the gas inside the torpedo-shaped piston 13a can be discharged to the outside of the injection molding machine 1 via the through hole 13h of the torpedo-shaped piston 13a and the through hole 17a of the rod 17, and the pressurizing piston 13d can be made to move smoothly.

[0102] ​Further, when the piston 13 moves to the Z-axis - side, the check ring 13b of the piston 13 is pushed to the Z-axis + side, and the groove portion 13j of the torpedo-shaped piston 13a is blocked by the check ring 13b, so that the backflow of the molten resin R to the first space S1 of the cylinder 11 via the groove portion 13j of the torpedo-shaped piston 13a can be suppressed.

[0103] Further, when the piston 13 moves to the Z-axis - side, the check ring 13b of the piston 13 is pushed to the Z-axis + side, and the groove portion 13j of the torpedo-shaped piston 13a is blocked by the check ring 13b, so that the backflow of the molten resin R to the first space S1 of the cylinder 11 via the groove portion 13j of the torpedo-shaped piston 13a can be suppressed.

[0104] Further, in the case where the second plate 12d is made of a material excellent in heat conductivity such as a ceramic plate, the heat of the second heating portion 15 can be efficiently transmitted to the molten resin. Further, in the case where the second heating portion 15 is damaged, the second plate 12d can be replaced when the lock nut 16 is loosened, and the replacement work of the second heating portion 15 is easy.

[0105] The plasticization of the resin material M and the injection of the molten resin R are repeatedly performed, and at the same time, for example, the injection molding machine 1 is moved, and the work table disposed on the Z-axis - side with respect to the injection molding machine 1 is moved, so that a workpiece required for the layer molding can be molded.

[0106] Thus, the injection molding machine 1 and the injection molding method of the present embodiment are provided with the blocking portion 13i which blocks the supply hole 11d of the cylinder 11 in conjunction with the movement of the torpedo-shaped piston 13a when the torpedo-shaped piston 13a moves to the Z-axis + side in order to plasticize the resin material M. Therefore, the backflow of the softened resin from the supply hole 11d of the cylinder 11 can be suppressed, and the resin material M can be favorably supplied to the first space S1 of the cylinder 11.

[0107] At this time, since the blocking portion 13i is in conjunction with the movement of the torpedo-shaped piston 13a, the position of the supply hole 11d of the cylinder 11 can be appropriately changed so that the supply hole 11d of the cylinder 11 is blocked by the blocking portion 13i when the resin material M is softened.

[0108] For example, by setting the position of the supply hole 11d as described above, the supply hole 11d can be blocked by the blocking portion 13i in a state where the piston 13 moves to the Z-axis + side and the filling rate of the resin material M becomes 100%. Therefore, in the case where a material having a low glass transition point is used as the resin material M, the backflow of the resin softened by the heating of the first heating portion 14 from the supply hole 11d of the cylinder 11 can be suppressed.

[0109] Further, in the present embodiment, since the closing portion 13i is formed on the side wall portion 13g of the torpedo-shaped piston 13a, the closing portion 13i can be arranged in the Z-axis direction between the supply hole 11d of the cylinder 11 and the second space S2 when the molten resin R in the second space S2 is extruded by the cylinder 11. Therefore, the molten resin R can be suppressed from flowing backward to the first space S1 of the cylinder 11, as a result of which the molten resin R can be suppressed from flowing backward from the supply hole 11d of the cylinder 11.

[0110] <Embodiment Two>

[0111] Figure 8 is a cross-sectional view schematically showing an injection molding machine of the present embodiment. Since the injection molding machine 21 of the present embodiment is substantially the same structure as the injection molding machine 1 of Embodiment One, the repeated explanation is omitted and the same components are explained using the same symbols.

[0112] As shown in Figure 8 , the injection molding machine 21 of the present embodiment is configured such that the end portion of the Z-axis + side of the cylinder 22 is open, and the plunger 23 presses the resin material M supplied to the first space S1 into the Z-axis - side via the open port 22a of the cylinder 22, and the resin material M can be compressed by the piston 13 and the plunger 23.

[0113] The plunger 23 has a columnar shape as a basic form. Also, a through hole 23a that penetrates in the Z-axis direction is formed in the center of the plunger 23, and the rod 17 passes through the through hole 23a. At this time, the face of the Z-axis - side of the plunger 23 can be formed as an inclined face corresponding to the shape of the end portion of the Z-axis + side of the torpedo-shaped piston 13a.

[0114] Such an injection molding machine 21 can compress the resin material M not only by the piston 13 but also by the piston 13 and the plunger 23. Therefore, even in the case where a material having a low filling rate in the first space S1 of the cylinder 22 is used as the resin material M, the resin material M can be well plasticized.

[0115] <Embodiment Three>

[0116] Figure 9 is a cross-sectional view schematically showing an injection molding machine of the present embodiment, showing a state where a resin material is supplied to the inside of a cylinder. Figure 10 is a perspective view showing a rod, a piston, and a closing portion in an injection molding machine of the present embodiment. Figure 11 is an enlarged perspective view showing the periphery of a closing portion in an injection molding machine of the present embodiment. Figure 12 is a perspective view showing a closing portion in an injection molding machine of the present embodiment.

[0117] Since the injection molding machine 31 of the present embodiment is substantially the same structure as the injection molding machine 1 of Embodiment 1, the repeated explanation is omitted, and the same symbol is used for the same parts. The injection molding machine 31 of the present embodiment is preferable, for example, when using a resin material having a higher glass transition point than polypropylene or polyamide (such as ABS, polycarbonate, or the like) to layer mold a workpiece.

[0118] Therefore, the resin material M supplied to the first space S1 of the cylinder 11 is difficult to soften due to heating of the first heating section 14 or the like, and is substantially softened only by shearing when passing through the groove section 32b of the torpedo-shaped piston 32a in the piston 32, and therefore, the supply hole 11d is formed near the end portion of the side wall section 11b of the cylinder 11 on the Z-axis + side, so that the resin material M is favorably supplied to the first space S1.

[0119] Furthermore, the piston 32 of the present embodiment adopts substantially the same structure as the piston 13 of Embodiment 1, but the groove section 32b is formed on the entire circumference of the side wall section of the torpedo-shaped piston 32a. Therefore, the groove section 32b of the torpedo-shaped piston 32a does not reach the supply hole 11d of the cylinder 11, and the closure section 33 is arranged on the Z-axis + side with respect to the piston 32 in a manner that the supply hole 11d is closed by the closure section 33.

[0120] As shown in FIG. 6, the closure section 33 is configured by a different member from the piston 32. As shown in FIG. 7, the closure section 33 has a closure wall 33a, a ring section 33b, and an engagement piece 33c. The closure wall 33a is in a form of a plate body having a thickness, and extends in the Z-axis direction. Furthermore, the outer peripheral shape (i.e., the side surface) of the closure wall 33a corresponds to the inner peripheral shape (i.e., the side surface) of the cylinder 11. Figures 9 to 11 Figure 12 As shown in FIG. 7, the closure wall 33a has a closure wall 33a, a ring section 33b, and an engagement piece 33c. The closure wall 33a is in a form of a plate body having a thickness, and extends in the Z-axis direction. Furthermore, the outer peripheral shape (i.e., the side surface) of the closure wall 33a corresponds to the inner peripheral shape (i.e., the side surface) of the cylinder 11.

[0121] The height of the closure wall 33a in the Z-axis direction is longer than the height of the supply hole 11d of the cylinder 11 in the Z-axis direction. That is, the outer peripheral surface of the closure wall 33a is formed in a shape capable of covering the entire area of the supply hole 11d along the inner peripheral surface of the cylinder 11.

[0122] The surface of the closure wall 33a on the Z-axis - side is formed as an inclined surface corresponding to the shape of the end portion on the Z-axis + side of the torpedo-shaped piston 32a. At this time, the end portion on the Z-axis + side of the closure wall 33a can have an inclined surface that inclines toward the Z-axis - side as it goes toward one side of the clockwise or counterclockwise direction in the circumferential direction of the piston 32.

[0123] ​The ring portion 33b is fixed to the end of the closing wall 33a on the Y-axis side. The ring portion 33b has a through portion that penetrates in the Z-axis direction, and the inner peripheral shape (i.e., inner periphery) of the through portion is slightly larger than the outer peripheral shape (i.e., outer periphery) of the rod 17. The engaging piece 33c protrudes from the closing wall 33a toward the Z-axis side, and is formed in a shape that can be engaged with the groove portion 32b of the torpedo-shaped piston 32a.

[0124] In the case where such a closing portion 33 is fixed to the piston 32, the ring portion 33b is passed through the rod 17, the closing wall 33a is placed on the torpedo-shaped piston 32a, and the engaging piece 33c is engaged with the groove portion 32b of the torpedo-shaped piston 32a.

[0125] Further, for example, in the case where the Z-axis side portion of the rod 17 is formed with a male screw, the closing portion 33 can be fixed to the piston 32 by screwing a nut 34 that passes through the rod 17 into the male screw of the rod 17, with the nut 34 and the torpedo-shaped piston 32a sandwiching the ring portion 33b. However, the fixing means is not limited as long as the closing portion 33 can be fixed to the piston 32 on the Z-axis + side.

[0126] Next, the flow of molding a workpiece using the injection molding machine 31 of the present embodiment will be described. Figure 13 and Figure 14 is a sectional view showing the operation for plasticizing the resin raw material in the injection molding machine of the present embodiment.

[0127] First, from a state where the piston 32 is disposed on the Z-axis + side most, the piston 32 is moved to the Z-axis - side via the rod 17, and at the same time, the resin raw material M is supplied from the supply hole 11d of the cylinder 11 to the first space S1 of the cylinder 11.

[0128] Then, as shown in Figure 9 , when the piston 32 reaches the Z-axis - side most, the supply of the resin raw material M is stopped. Next, as shown in Figure 13 , the piston 32 is moved to the Z-axis + side via the rod 17.

[0129] Thus, the resin raw material M is compressed by the piston 32, the obturator portion 11a of the cylinder 11, and the side wall portion 11b of the cylinder 11, and at the same time, is plasticized to become a molten resin R by passing through the groove portion 32b of the torpedo-shaped piston 32a, and flows into the second space S2 of the cylinder 11. Here, in the case where the Z-axis + side face of the closing wall 33a of the closing portion 33 is provided with an inclined face, the resin raw material M can be guided well into the groove portion 32b of the torpedo-shaped piston 32a.

[0130] At this time, as described above, the resin raw material M of the present embodiment is softened substantially only by shearing when passing through the groove portion 32b of the torpedo-shaped piston 32a, and thus is difficult to soften by heating or the like based on the first heating portion 14. Therefore, in the case where the resin raw material M is softened by heating or the like based on the first heating portion 14, the resin raw material M can be softened by the shearing when passing through the groove portion 32b of the torpedo-shaped piston 32a, and thus the resin raw material M can be plasticized more efficiently.Figure 13 In this state, the softened molten resin R does not substantially flow back from the supply hole 11d of the cylinder 11.

[0131] Further, when the piston 32 is moved to the Z-axis + side via the rod 17, as shown in Figure 14 the piston 32 does not reach the supply hole 11d of the cylinder 11, but the blocking portion 33 reaches the supply hole 11d, and the blocking portion 33 blocks the supply hole 11d.

[0132] Thus, since the piston 32 does not reach the supply hole 11d of the cylinder 11, but the blocking portion 33 blocks the supply hole 11d, the molten resin R that is plasticized by the resin raw material M passing through the groove portion 32b of the torpedo-shaped piston 32a can be inhibited from flowing back from the supply hole 11d.

[0133] Next, when the piston 32 is moved to the Z-axis - side via the rod 17 while the piston 32 is positioned at the Z-axis + side, the molten resin R is pressed by the piston 32, and the molten resin R is injected via the communication path 12b and the injection port 12a of the injection portion 12.

[0134] At this time, when the piston 32 is moved to the Z-axis - side, the engaging piece 33c of the blocking portion 33 engages with the groove portion 32b of the torpedo-shaped piston 32a between the supply hole 11d of the cylinder 11 and the second space S2 in the Z-axis direction, and thus the molten resin R can be inhibited from flowing back to the first space S1 of the cylinder 11.

[0135] Thus, as with the injection molding machine 1 and the injection molding method of Embodiment One, the injection molding machine 31 and the injection molding method of the present embodiment are also such that, when the torpedo-shaped piston 32a is moved to the Z-axis + side in order to plasticize the resin raw material M, the blocking portion 33 is linked with the movement of the torpedo-shaped piston 32a, and thus the position of the supply hole 11d of the cylinder 11 can be appropriately changed so that the supply hole 11d of the cylinder 11 is blocked by the blocking portion 33 when the resin raw material M is softened.

[0136] Further, in the present embodiment, a configuration in which the blocking portion 33 is disposed on the Z-axis + side with respect to the piston 32 is described, but the same can also be implemented using the piston 13 of Embodiment One.

[0137] <Embodiment Four>

[0138] Figure 15 is a partial cross-sectional view that schematically shows the injection molding machine of the present embodiment, and shows a state before the insertion portion blocks the exhaust hole of the cylinder. Figure 16 is a partial cross-sectional view that schematically shows the injection molding machine of the present embodiment, and shows a state after the insertion portion blocks the exhaust hole of the cylinder. Figure 17 is a perspective view that shows the blocking portion of the injection molding machine of the present embodiment.

[0139] Since the injection molding machine 41 of this embodiment has a structure that is substantially the same as that of the injection molding machine 31 of Embodiment 3, repeated descriptions are omitted, and the same reference numerals are used to describe the same parts. Regarding the injection molding machine 41 of this embodiment, it is preferable, for example, to supply the resin raw material M with a glass transition point lower than that of ABS, polycarbonate, etc. (such as polypropylene, polyamide, etc.) to the first space S1 of cylinder 11 by airflow.

[0140] For example, when resin raw material M is supplied to the first space S1 of cylinder 11 by airflow, it is necessary to discharge gas from the first space S1 of cylinder 11. On the other hand, it is necessary to prevent the softened resin from being discharged along with the exhaust gas.

[0141] Furthermore, in order to properly supply the resin material M to the first space S1, when the supply hole 11d is formed near the Z-axis+ side end in the side wall portion 11b of the cylinder 11, it is necessary to close the supply hole 11d when the filling rate of the resin material M in the first space S1 reaches 100%.

[0142] Therefore, the injection molding machine 41 of this embodiment has a structure that satisfies the above-described elements, including the cylinder 11 and the sealing section 42. Figure 15 and Figure 16 As shown, cylinder 11 adopts a structure that is substantially the same as that of cylinder 11 of injection molding machine 31 in embodiment 3, but an exhaust hole 11f is formed on the blocking part 11a that passes through the blocking part 11a of cylinder 11 in the Z-axis direction.

[0143] like Figure 17 As shown, the closing part 42 includes a closing wall 42a, a guide part 42b, a ring part 42c, and a locking piece 42d. The closing wall 42a is based on a plate with thickness and extends in the Z-axis direction.

[0144] The outer peripheral shape (i.e., side surface) of the sealing wall 42a corresponds to the inner peripheral shape (i.e., side surface) of the cylinder 11. Moreover, when viewed from the Z-axis direction, the sealing wall 42a is positioned at a location where the exhaust port 11f of the cylinder 11 can be inserted, and has a peripheral shape that is approximately equal to the peripheral shape of the exhaust port 11f.

[0145] Regarding the height of the sealing wall 42a in the Z-axis direction, for example, it has the height to be able to close the supply hole 11d before the piston 43 moves from the piston 43 toward the Z-axis+ side and the filling rate of the resin raw material M in the first space S1 of the cylinder 11 reaches 100% until the piston 43 reaches the position closest to the Z-axis+ side, and the height to which the sealing wall 42a can be inserted into the exhaust hole 11f of the cylinder 11 after a predetermined period (e.g., immediately thereafter) has been passed after closing the supply hole 11d.

[0146] Here, as Figure 15As shown, the piston 43 of the present embodiment has a torpedo-shaped piston 43a, a check ring 43b, and a stopper 43c. The torpedo-shaped piston 43a has a cylindrical shape as a basic form, and the Z-axis + side end portion of the torpedo-shaped piston 43a is fixed to the Z-axis - side end portion of the rod 44. Here, the rod 44 can omit the through-hole corresponding to the through-hole 17a of the rod 17 of Embodiment 1.

[0147] A groove portion 43d is formed on the peripheral surface of the torpedo-shaped piston 43a. The groove portion 43d extends in the Z-axis direction and is arranged at substantially equal intervals in the peripheral direction of the torpedo-shaped piston 43a.

[0148] The check ring 43b is annular and has an outer peripheral shape substantially equal to the inner peripheral shape of the cylinder 11, and is arranged on the Z-axis - side with respect to the torpedo-shaped piston 43a. The stopper 43c holds the check ring 43b at the Z-axis - side end portion of the torpedo-shaped piston 43a.

[0149] The stopper 43c has, for example, a columnar portion 43e protruding from the Z-axis - side end portion of the torpedo-shaped piston 43a, and branch portions 43f branching radially from the Z-axis - side end portion of the columnar portion 43e with the columnar portion 43e as a center.

[0150] Further, the check ring 43b is arranged between the Z-axis - side end portion of the torpedo-shaped piston 43a and the branch portions 43f in a state where the columnar portion 43e passes through the through-hole of the check ring 43b. At this time, the length of the columnar portion 43e in the Z-axis direction is longer than the thickness of the check ring 43b in the Z-axis direction, so that the check ring 43b can move in the Z-axis direction.

[0151] The guide portion 42b guides the resin raw material M of the first space S1 of the cylinder 11 to the groove portion 32b of the torpedo-shaped piston 32a. As shown, Figure 17 The guide portion 42b has a discontinuous cylindrical shape as a basic form, which is formed integrally with the Z-axis - side portion of the closing wall 42a. The outer peripheral shape (i.e., the side surface) of the guide portion 42b corresponds to the inner peripheral shape (i.e., the side surface) of the cylinder 11.

[0152] The Z-axis + side surface of the guide portion 42b has an inclined surface that is inclined in a spiral shape toward the Z-axis - side as it goes toward the counterclockwise (but can be clockwise) side in the peripheral direction of the piston 32. Further, the Z-axis - side surface of the guide portion 42b is formed as an inclined surface corresponding to the shape of the Z-axis + side end portion of the torpedo-shaped piston 32a.

[0153] The Z-axis + side portion of the closing wall 42a protrudes from the Z-axis + side surface of such a guide portion 42b toward the Z-axis + side, and functions as an insertion portion that plugs the exhaust hole 11f of the cylinder 11 in a state of being inserted into the exhaust hole 11f.

[0154] The ring portion 42c is fixed inside the guide portion 42b. The ring portion 42c has a through portion that penetrates in the Z-axis direction, and the inner peripheral shape (i.e., inner periphery) of the through portion is slightly larger than the outer peripheral shape (i.e., outer periphery) of the rod 17. The engaging piece 42d protrudes from the closing wall 42a toward the Z-axis- side, and is formed in a shape that can be engaged with the groove portion 43d of the torpedo-shaped piston 43a.

[0155] In the case where the closing portion 42 of the above-described structure is fixed to the piston 43, the ring portion 42c is passed through the rod 17, the guide portion 42b is placed on the torpedo-shaped piston 43a, and the engaging piece 42d is engaged with the groove portion 43d of the torpedo-shaped piston 43a. Also, by fixing the ring portion 42c to the rod 17, the closing portion 42 can be fixed to the piston 43. However, the means of fixing the closing portion 42 to the piston 43 on the Z-axis+ side is not limited.

[0156] In the case where the injection molding machine 41 of such a structure is used to inject the molten resin R, when the piston 43 is moved to the Z-axis+ side to a state before the filling rate of the resin raw material M in the first space S1 reaches 100%, the closing wall 42a closes the supply hole 1 Id. Thereby, backflow of the softened resin from the supply hole 1 Id can be suppressed.

[0157] At this time, from the start of the movement of the piston 43 to the Z-axis+ side until the supply hole 1 Id based on the closing wall 42a is closed for a predetermined period of time, since the exhaust hole 1 If of the cylinder 11 is open, the gas that flows into the first space S1 in order to supply the resin raw material M to the first space S1 can be favorably exhausted.

[0158] Then, when the piston 43 is further moved to the Z-axis+ side, the portion of the closing wall 42a on the Z-axis+ side, i.e., the insertion portion, is inserted into and blocks the exhaust hole 1 If of the cylinder 11. Thereby, the discharge of the softened resin from the exhaust hole 1 If can be suppressed.

[0159] Then, when the piston 43 is moved to the Z-axis- side, the molten resin R is pressed by the piston 43, and the molten resin R is injected via the communication path 12b and the injection port 12a of the injection portion 12. At this time, the closing wall 42a is removed from the exhaust hole 1 If of the cylinder 11.

[0160] By thus reciprocating the piston 43 in the Z-axis direction, the plasticization of the resin raw material M and the injection of the molten resin R can be repeatedly performed as described above, and the insertion and removal of the closing wall 42a to and from the exhaust hole 1 If of the cylinder 11 are performed each time. Therefore, the exhaust hole 1 If of the cylinder 11 can be suppressed from being blocked by the hardened resin.

[0161] Further, in the present embodiment, the exhaust hole 11f is formed in the closed portion 11a of the cylinder 11, but can be formed in the plunger 23 of Embodiment 2. Further, in the present embodiment, the insertion portion is formed by the closed wall 42a, but can be provided so as to protrude toward the + side of the Z axis from the torpedo-shaped piston 13a of Embodiment 1.

[0162] The present application is not limited to the above-described embodiments, and can be appropriately changed within the scope of the gist thereof.

[0163] For example, the injection molding machine of the above-described embodiments is provided with one cylinder and plunger, but can be provided with a plurality of cylinders and plungers.

[0164] For example, the injection molding machine of the above-described embodiments is provided with the first heating portion 14 and the second heating portion 15, but can be omitted. Further, for example, the pressurizing piston 13d and the like can be omitted.

[0165] For example, the position of the resin raw material supply hole and the shape and arrangement of the closed portion are not limited to the above-described, and in general, as long as the structure is such that the closed portion moves in conjunction with the movement of the torpedo-shaped piston and is capable of closing the supply hole so that softened resin raw material and molten resin do not flow backward from the supply hole.

[0166] It will be apparent to those skilled in the art that various modifications can be made to the embodiments of the disclosure described above with reference to the disclosure. These modifications should not be considered to be outside the scope of the present application, and it will be apparent to those skilled in the art that all such modifications are intended to be included within the scope of the appended claims.

Claims

1. An injection molding machine, comprising: A cylinder, which contains resin raw materials; A torpedo-shaped piston, which plasticizes the resin raw material by moving inside the cylinder to form molten resin, and then extrudes the molten resin; and An injection unit, disposed at one end of the cylinder, injects the molten resin. The injection molding machine also features: A supply hole is formed in the side wall of the cylinder to supply the resin raw material into the interior of the cylinder; The sealing section, when the torpedo-shaped piston moves to the other end of the cylinder in order to plasticize the resin raw material, is linked to the movement of the torpedo-shaped piston and simultaneously closes the supply hole. An exhaust port that communicates the space on one end of the cylinder, opposite to the torpedo-shaped piston, with the outside; and The insertion part is linked to the movement of the torpedo-shaped piston, and when the supply hole is closed by the sealing part, it is inserted into the exhaust hole to block the exhaust hole.

2. The injection molding machine according to claim 1, characterized in that, The sealing portion blocks the supply hole in such a way that the softened resin raw material or the molten resin does not flow back from the supply hole.

3. The injection molding machine according to claim 1, characterized in that, The supply hole is positioned such that (St-x) / St≤γ. Where St is the stroke from the bottom dead center to the top dead center of the torpedo-shaped piston, γ is the pre-set filling rate of the resin raw material, and x is the distance from the other end of the cylinder to the center of the supply hole.

4. The injection molding machine according to any one of claims 1 to 3, characterized in that, The closure is formed on the side of the torpedo-shaped piston.

5. The injection molding machine according to claim 1 or 2, characterized in that, The closure is positioned on one side of the opposite end of the cylinder relative to the torpedo-shaped piston.

6. The injection molding machine according to any one of claims 1 to 3, characterized in that, The other end of the cylinder is open. The injection molding machine also includes a plunger that presses the resin material supplied to the interior of the cylinder through the other end of the cylinder.

7. The injection molding machine according to any one of claims 1 to 3, characterized in that, The resin raw material is a material with a lower glass transition point compared to polycarbonate.

8. The injection molding machine according to any one of claims 1 to 3, characterized in that, The resin raw material is a material with a higher glass transition point than polypropylene.

9. An injection molding method comprising using an injection molding machine according to any one of claims 1 to 8, moving a torpedo-shaped piston inside a cylinder to plasticize a resin raw material to form a molten resin, and injecting the molten resin therein. During the plasticization of the resin raw material, a sealing part that is linked to the movement of the torpedo-shaped piston seals the resin raw material supply hole formed on the side wall of the cylinder.

10. The injection molding method according to claim 9, characterized in that, The sealing portion blocks the supply hole in such a way that the softened resin raw material or the molten resin does not flow back from the supply hole.

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