Direct molding screws, injection molding equipment, and kneading pieces

Abstract

To provide a screw for direct molding capable of kneading a molten resin transported from the upstream side and an additive material introduced from the middle and more uniformly dispersing the additive material.SOLUTION: The present invention relates to a direct molding screw 18 which transfers a thermoplastic resin supplied from the upstream side to the downstream side while melting it, and kneads the transferred molten resin with an additive fed from the middle, the direct molding screw includes a screw body 60 and a kneading piece body 70, the screw body includes a first stage S1 and a second stage S2, wherein the outer peripheral surface of the first stage is provided with a helical main flight, and the outer peripheral surface of the second stage is provided with multiple helical flights, and wherein the outer peripheral surface of the kneading piece body is provided with multiple helical flights, and at least one notch is formed in the middle of the flight provided on the kneading piece.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a screw for direct molding, an injection molding apparatus, and a kneaded piece.

Background Art

[0002] A thermoplastic resin (a plurality of resin pellets) supplied from the upstream side (hopper) is melted by heat transfer from a heating cylinder and shear heat generation due to the rotation of a screw, and is transferred to the downstream side. The molten resin thus transferred and a reinforcing fiber as an additive introduced from the middle (from a fiber inlet formed in the heating cylinder) are kneaded, and a molded product is molded (directly molded) by injecting the molten resin in which the reinforcing fiber is kneaded into a mold (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, there is no mention at all about uniformly dispersing an additive in the process of kneading the molten resin transferred from the upstream side and the additive introduced from the middle, and there is room for improvement in this regard.

[0005] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

Means for Solving the Problems

[0006] A direct molding screw according to one embodiment is a direct molding screw that melts a thermoplastic resin supplied from the upstream side and transports it to the downstream side, and kneads the transported molten resin with an additive that is introduced midway, comprising a screw body and a kneading piece body detachably attached to the downstream end of the screw body, wherein the screw body includes a first stage located on the upstream side and a second stage located on the downstream side, the outer circumferential surface of the first stage is provided with a helical main flight, the outer circumferential surface of the second stage is provided with a plurality of helical flights, the outer circumferential surface of the kneading piece body is provided with a plurality of helical flights, and at least one notch is formed in the middle of the flights provided on the kneading piece. [Effects of the Invention]

[0007] According to the above embodiment, it is possible to provide a direct molding screw that can knead molten resin being transported from the upstream side with additives being added midway through the process, thereby dispersing the additives more uniformly. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the overall configuration of the injection molding apparatus 1 according to the embodiment. [Figure 2] This is a perspective view of the heating cylinder 17. [Figure 3] This is a side view of screw 18. [Figure 4] This is an enlarged view of Stage 1, S1. [Figure 5] This diagram (viewed from the direction of arrow AR1 in Figure 4) shows how the solid resin in the flight groove 62 gradually decreases as it melts. [Figure 6] This diagram (viewed from the direction of arrow AR1 in Figure 4) shows how the solid resin between the sub-flight 63 and the main flight 61 is pushed towards the main flight 61 and raised due to the action of the sub-flight 63. [Figure 7] This is an enlarged view of Stage 2, S2. [Figure 8] This graph shows the weighing time when two flights 65 and 66 are provided (embodiment) and the weighing time when only one flight is provided (comparative example). [Figure 9] This is a magnified view of the 70th mixing piece. [Figure 10] This is a magnified view of the mixed piece 70 (modified version). [Figure 11] This is a perspective view of screw 18. [Modes for carrying out the invention]

[0009] The following describes specific embodiments in detail with reference to the drawings. However, the invention is not limited to the embodiments described below. Also, for clarity, the following descriptions and drawings have been simplified as appropriate. <Overall configuration of injection molding equipment> First, with reference to Figure 1, the overall configuration of the injection molding apparatus 1 (injection molding machine) according to the embodiment will be described. Figure 1 is a diagram showing the overall configuration of the injection molding apparatus 1 according to the embodiment.

[0010] The injection molding apparatus 1 is a device that melts thermoplastic resin (multiple resin pellets) supplied from the upstream side (hopper 20) by heat transfer from the heating cylinder 17 and shear heat generated by the rotation of the direct molding screw 18, and transfers it to the downstream side. The molten resin being transferred is mixed with an additive that is introduced midway (from the additive inlet 17b formed in the heating cylinder 17), and this molten resin mixed with the additive is injected into a mold (a fixed mold 21 and a movable mold 25 that are clamped together) to form a molded product (a molded product in which the additive is uniformly dispersed) (direct molding).

[0011] Hereinafter, an example of using reinforcing fibers such as glass fibers and carbon fibers as additives will be described. Note that the reinforcing fibers fed into the injection molding apparatus 1 midway may be continuous reinforcing fibers like rovings, or may be reinforcing fibers (plural) obtained by previously cutting continuous reinforcing fibers like rovings into a predetermined length. Note that the additives are not limited to reinforcing fibers such as glass fibers and carbon fibers, and additives other than reinforcing fibers such as glass fibers and carbon fibers may also be used.

[0012] As shown in FIG. 1, the injection molding apparatus 1 includes a plasticizing unit 12 (injection device) and a mold clamping unit 13. <Configuration of plasticizing unit> The plasticizing unit 12 mainly includes a heating cylinder 17, a direct molding screw 18 provided inside the heating cylinder 17 (hereinafter simply referred to as screw 18), and a hopper 20 for supplying thermoplastic resin (a plurality of resin pellets).

[0013] FIG. 2 is a perspective view of the heating cylinder 17.

[0014] As shown in FIG. 2, the heating cylinder 17 is a cylindrical cylinder. A resin inlet 17a for injecting thermoplastic resin (a plurality of resin pellets) is formed on the upstream side of the heating cylinder 17, and an additive inlet 17b for injecting additives is formed in an intermediate portion between the upstream side and the downstream side of the heating cylinder 17. Further, an injection nozzle 19 for injecting the molten resin in which the additives are kneaded is provided at the end portion on the downstream side of the heating cylinder 17.

[0015] As shown in Fig. 1, the plasticizing unit 12 includes a mechanism part 16 containing an injection servo motor or the like that controls the rotation and axial movement of the screw 18, and a control device 30 that controls the mechanism part 16 (such as injection control and pressure holding control in the injection process, back pressure control in the metering process, etc.). The control device 30 also controls the mold clamping cylinder 23 (hydraulic device) and the mold opening / closing servo motor 28 described later. In Fig. 1, reference numeral 14 indicates the bed on which the plasticizing unit 12 and the mold clamping unit are installed. Reference numeral 15 indicates the base installed on the bed 14. The mechanism part 16 is installed on the base 15. <Configuration of Mold Clamping Unit 13> As shown in Fig. 1, the mold clamping unit 13 includes a fixed platen 22 to which the fixed mold 21 is attached, and a movable platen 26 to which the movable mold 25 is attached. Mold clamping cylinders 23 are arranged near the four corners of the fixed platen 22, and a tie bar 24 is formed by the rod of the mold clamping cylinder 23. A groove-shaped half nut locking part 24a is formed from the middle part to the tip of the outer periphery of the tie bar 24. The mold clamping cylinder 23 is connected to a hydraulic device (not shown), and the hydraulic pressure of the hydraulic oil sent to the mold clamping cylinder 23 is detected by a pressure sensor provided in the pipeline to control the mold clamping force.

[0016] The tie bar 24 is inserted into through holes formed near the four corners of the movable platen 26. Half nuts 27 are respectively provided around the through holes on the back side of the movable platen 26 through which the tie bar 24 is inserted. Further, a mold opening / closing mechanism 29 including a mold opening / closing servo motor 28 and a ball screw mechanism is provided on the bed 14, and the movable platen 26 can move in the mold opening / closing direction on the bed 14 by the mold opening / closing mechanism 29. In Fig. 1, reference numeral 31 indicates the operating device, reference numeral 32 indicates the display device of the operating device 31, reference numeral 40 indicates various operation keys, reference numeral 41 indicates various switches, reference numeral 44 indicates each screen of the display device 32, and reference numeral 53 indicates the operation part. <Operation of Mold Clamping Unit> First, the movable platen 26 is moved by controlling the mold opening / closing servo motor 28 to bring the fixed mold 21 into contact with the movable mold 25. Next, the movable platen 26 is fixed to the tie bar 24 by engaging the half-nut locking portion 24a and the half-nut 27 of the tie bar 24. Next, the fixed mold 21 and the movable mold 25 are tightened by controlling the mold clamping cylinder 23. After the mold clamping is performed in this manner, molten resin (molten resin mixed with additives) is injected from the plasticizing unit 12 into the cavity of the mold (the clamped fixed mold 21 and movable mold 25) to form a molded product (a molded product in which the additives are uniformly dispersed). <Screw configuration> Next, the configuration of screw 18 will be described with reference to Figure 3.

[0017] Figure 3 is a side view of screw 18.

[0018] The screw 18 is a direct molding screw that melts and transfers thermoplastic resin (resin pellets) supplied from the upstream side (hopper 20) to the downstream side, and mixes the molten resin being transferred with additives that are introduced midway (from the additive inlet 17b formed in the heating cylinder 17). The screw 18 is rotatably mounted inside the heating cylinder 17 and is capable of moving back and forth in the axial direction. As shown in Figure 3, the screw 18 comprises a screw body 60 and a mixing piece 70 that is detachably attached to the downstream end of the screw body 60.

[0019] The screw body 60 includes a first stage S1 located on the upstream side and a second stage S2 located on the downstream side. <Structure of Stage 1> Figure 4 is an enlarged view of the first stage, S1.

[0020] The first stage S1 is a stage for melting resin. As shown in Figure 4, a spiral main flight 61 is provided on the outer circumferential surface of the first stage S1. The main flight 61 is provided in the range from the upstream end to the downstream end of the first stage S1. In addition, a spiral groove 62 (hereinafter referred to as flight groove 62) is formed on the outer circumferential surface of the first stage S1, defined by the main flight 61.

[0021] The first stage S1 includes a supply section A1, a compression section A2, and a metering section A3 arranged from upstream to downstream. A spiral-shaped sub-flight 63 is provided on the outer surface of the first stage S1. The sub-flight 63 branches off from the main flight 61 at the boundary between the compression section A2 and the metering section A3 and rejoins the main flight 61 at the downstream end of the first stage S1. The sub-flight 63 is provided such that the distance between it and the main flight 61 narrows as it moves downstream.

[0022] Thermoplastic resin (multiple resin pellets) is supplied from the hopper 20 to the supply unit A1 via a resin inlet 17a formed in the heating cylinder 17, and is transferred downstream from the supply unit A1 by a rotationally driven screw 18. In this process, the thermoplastic resin melts mainly due to heat transfer from the heating cylinder 17, becoming a semi-molten resin state in which molten resin and solid resin are mixed.

[0023] In the compression section A2, the groove depth of the flight groove 62 gradually decreases toward the downstream end of the first stage S1, so the semi-molten resin being transported from the supply section A1 is gradually compressed. During this process, the semi-molten resin is further melted by heat transfer from the heating cylinder 17 and shear heat generated between the heating cylinder 17 and the other components.

[0024] Figure 5 shows how the solid resin in the flight groove 62 gradually decreases as it melts (viewed from the direction of arrow AR1 in Figure 4). Figure 6 shows how the solid resin between the sub-flight 63 and the main flight 61 is pushed towards the main flight 61 and raised due to the action of the sub-flight 63 (viewed from the direction of arrow AR1 in Figure 4).

[0025] As shown in Figure 5, the amount of solid resin gradually decreases as it melts, and the distance L1 between the solid resin and the inner wall 17c of the heating cylinder 17 increases.

[0026] However, as shown in Figure 6, in the metering section A3, the sub-flight 63 is provided such that the distance L2 between it and the main flight 61 narrows as it moves downstream. As a result, the solid resin between the sub-flight 63 and the main flight 61 is pushed towards the main flight 61 and raised, shortening the distance L1 between the solid resin between the sub-flight 63 and the main flight 61 and the inner wall 17c of the heating cylinder 17. This promotes the melting of the thermoplastic resin due to heat transfer from the heating cylinder 17 and shear heat generated between the heating cylinder 17 and the inner wall 17c, etc., compared to the case where the sub-flight 63 is not provided.

[0027] As described above, when the thermoplastic resin melts, in the range from just before the compression section A2 to the downstream end of the first stage S1, the thermoplastic resin exists in a semi-molten state with solid resin remaining. Therefore, the pressure applied to the semi-molten resin fluctuates (varies) depending on the axial position of the heating cylinder 17, which can cause the screw 18 to run out (eccentric rotation of the screw 18). (As a result, the top of the main flight 61 may come into contact with the inner wall 17c of the heating cylinder 17, causing wear on the top of the main flight 61, etc.)

[0028] To suppress this wobbling, as shown in the "AA cross-sectional view" in Figure 6, a stepped portion 64 into which molten resin enters is formed at the top of the main flight 61 by cutting out the downstream portion of the top of the main flight 61. The stepped portion 64 is formed in the range where the pressure applied to the molten resin (semi-molten resin) fluctuates, in this case, from just before the compression section A2 to the downstream end of the first stage S1.

[0029] Pressurized molten resin enters the space between the top of the main flight 61 (stepped portion 64) and the inner wall 17c of the heating cylinder 17. This molten resin generates a greater lubrication pressure between the top of the main flight 61 and the inner wall 17c of the heating cylinder 17 compared to the case where the stepped portion 64 is not formed on the top of the main flight 61. This suppresses the runout of the screw 18. As a result, wear on the top of the main flight 61 and other parts caused by the runout of the screw 18, which would otherwise come into contact with the inner wall 17c of the heating cylinder 17, is suppressed. <Structure of Stage 2> Figure 7 is an enlarged view of the second stage, S2.

[0030] The second stage S2 is a multi-start screw-shaped stage for mixing additives and molten resin. As shown in Figure 11, the second stage S2 includes a supply section A5, a compression section A6, and a metering section A7 arranged from upstream to downstream. Figure 11 is a perspective view of the screw 18. The inventors have found that in direct molding, the transfer capacity (transfer amount, transfer speed, etc.) for transferring the molten resin mixed with additives is more stable and less prone to variation when multiple (e.g., two) flights are provided on the outer surface of the second stage S2 compared to when only one flight is provided on the outer surface of the second stage S2. Based on this finding, as shown in Figure 7, two spiral flights 65 and 66 are provided on the outer surface of the second stage S2.

[0031] Each of the flights 65 and 66 is positioned within the range from the upstream end to the downstream end of the second stage S2. One flight 65 is positioned circumferentially offset by 180° from the other flight 66. The number of flights provided in the second stage S2 is not limited to two; there may be three or more, but considering the strength of the flights, around three is preferable.

[0032] In the second stage S2, the molten resin transferred from the first stage S1 is mixed with the additive introduced through the additive inlet 17b formed in the heating cylinder 17 by a rotating screw 18 and transferred downstream.

[0033] In this case, by providing two flights 65 and 66 in the second stage S2, the amount of molten resin mixed with additives that can be transferred can be increased (the transfer speed can be increased) compared to the case where only one flight is provided. This effect will be explained in comparison with the screw of the comparative example. The screw 1 of this embodiment includes (1) a stepped portion 64 formed at the top of the main flight 61 of the first stage S1, (2) a sub-flight 63 provided in the first stage S1, (3) two flights 65 and 66 provided in the second stage S2, and (4) a kneading piece 70 attached to the downstream end of the screw body 60. On the other hand, the screw of the comparative example has the same configuration as the screw 1 of this embodiment, except that there is one flight provided in the second stage S2.

[0034] Figure 8 is a graph showing the metering time when direct molding is performed using the screw 1 of this embodiment and the metering time when direct molding is performed using the screw of the comparative example. Metering time refers to the time from the start of screw rotation until the required amount of molten resin accumulates at the tip of the screw (screw body 60). Referring to Figure 8, the metering time when using the screw 1 of this embodiment, which has two flights 65 and 66, is 25.7 seconds, and the metering time when using the screw of the comparative example, which has one flight, is 73.0 seconds. In other words, it can be seen that the metering time is shorter when using the screw 1 of this embodiment, which has two flights 65 and 66, compared to when using the screw of the comparative example, which has one flight. This is because by providing two flights 65 and 66, the amount of molten resin (molten resin mixed with additives) transferred in the second stage S2 can be increased (the transfer speed can be increased) compared to when only one flight is provided.

[0035] Furthermore, in the second stage S2, by providing two flights 65 and 66, it is possible to perform the same amount of mixing per rotation of screw 18 as would be for two rotations of a screw with only one flight.

[0036] As described above, in the second stage S2, by providing two flights 65 and 66, the molten resin and additive can be mixed efficiently and dispersed in a shorter time compared to the case where only one flight is provided. Furthermore, because mixing and dispersion can be performed in a short time, it is possible to suppress the additive (reinforcement fiber) from breaking more than necessary in the second stage S2.

[0037] In the second stage S2, if the heating cylinder 17 is filled with molten resin, the additive cannot be introduced through the additive inlet 17b. Therefore, by making the molten resin transfer capacity (transfer amount, transfer speed, etc.) in the second stage S2 greater than that in the first stage S1, the pressure applied to the molten resin directly below the additive inlet 17b is reduced, thereby creating a space directly below the additive inlet 17b where there is no molten resin and it is suitable for introducing the additive (starvation zone A4; see Figure 3). Furthermore, the molten resin transfer capacity (transfer volume, transfer speed, etc.) in the second stage S2 can be increased compared to the molten resin transfer capacity in the first stage S1 by making the depth of the flight grooves in the second stage S2 (helical grooves defined by two flights 65 and 66; hereinafter referred to as flight grooves 67; see Figure 8) deeper than the depth of the flight grooves 62 in the first stage S1 (or by making the pitch of flights 65 and 66 in the second stage S2 greater than the pitch of the main flight 61 in the first stage S1).

[0038] Furthermore, the outer diameter of the tops of flights 65 and 66 of the second stage S2 may be recut by 0.05 to 0.2 mm in diameter. The range in which the outer diameter of the tops of flights 65 and 66 of the second stage S2 is recut is the range indicated by symbol A8 between positions P1 and P2 in Figure 11 (a range shorter than the supply section A5 of the second stage S2). Position P1 is the position directly below the additive inlet 17b when the screw 18 is in its furthest forward position. Position P2 is the position directly below the additive inlet 17b when the screw 18 is retracted by its maximum stroke during the metering operation.

[0039] By recutting the outer diameter of the tops of flights 65 and 66 in the second stage S2 by 0.05 to 0.2 mm in diameter, a gap can be secured between the inner wall 17c of the heating cylinder 17 and the tops of flights 65 and 66 in the second stage S2. This reduces the shearing force on the additive, making it more difficult for the additive to be cut, and allowing the additive (fiber roving) to be stably wound by the screw rotation. <Composition of the kneaded pieces> Figure 9 is a magnified view of the kneading piece 70. Figure 10 is a magnified view of the kneading piece 70 (modified version).

[0040] The mixing piece 70 is a multi-start threaded section that further mixes the molten resin (molten resin mixed with additives) that is transferred from the second stage S2.

[0041] As shown in Figure 9, the kneading piece 70 comprises a kneading piece body 71 and a threaded portion 72. The axial length of the kneading piece body 71 is shorter than the axial length of the second stage S2. The kneading piece body 71 is detachably attached to the downstream end of the screw body 60 by screwing the threaded portion 72 into a threaded hole (not shown) formed at the downstream end of the screw body 60 (see Figure 3). Alternatively, as shown in Figure 10, the threaded portion 72 may be provided at the downstream end of the screw body 60, and a threaded hole (not shown) into which the threaded portion 72 is screwed may be formed in the kneading piece body 71.

[0042] Multiple spiral flights 73 are provided on the outer surface of the kneading piece body 71. The flights 73 are provided in the range from the upstream end to the downstream end of the kneading piece body 71. In addition, spiral grooves (hereinafter referred to as flight grooves 74) defined by the flights 73 are formed on the outer surface of the kneading piece body 71. The number of flights 73 provided on the kneading piece body 71 is greater than the number of flights provided in the second stage S2 (here, two flights 65 and 66). Specifically, it is desirable that the number of flights 73 provided on the kneading piece body 71 be 2 to 10 times the number of flights provided in the second stage S2.

[0043] The lead angle θ1 of the flight 73 provided on the mixing piece body 71 is greater than the lead angle θ2 of the flights 65 and 66 provided on the second stage S2. A lead angle θ1 of 30° to 60° and a lead angle θ2 of 10° to 25° are desirable. By changing the processing capacity [kg / hr] on the upstream side (depending on θ2) and the processing capacity [kg / hr] of the downstream mixing piece 70 (depending on θ1), the pressure of the mixing piece 70 is changed, and the mixing action (force on the molten resin × time) is adjusted. The groove depth of the flight groove 74 defined by the flight 73 provided on the mixing piece body 71 is slightly shallower than the groove depth of the flight groove 67 defined by the flights 65 and 66 provided on the second stage.

[0044] In the middle of each flight 73, a first notch 75 and a second notch 76 are formed to merge molten resin (molten resin mixed with additives) passing through separate flight grooves 74. The first notch 75 is arranged in a ring shape in the circumferential direction. Similarly, the second notch 76 is also arranged in a ring shape in the circumferential direction. Note that there may be one or more notches, not just two.

[0045] The molten resin (molten resin mixed with additives) transferred from the second stage S2 is mixed and transferred downstream by a mixing piece 70 which is rotated together with the screw body 60.

[0046] In this case, the number of flights 73 on the mixing piece body 71 is greater than the number of flights in the second stage S2 (here, two flights 65 and 66), so more mixing can be performed per rotation of the screw 18 than in the second stage S2. Also, since the axial length of the mixing piece body 71 is shorter than the axial length of the second stage S2, the molten resin (molten resin with additives mixed in) can be mixed more efficiently and in a shorter time, and the additives can be dispersed, compared to the second stage S2. Furthermore, since the groove depth of the flight grooves 74 on the mixing piece body 71 is slightly shallower than the groove depth of the flight grooves 67 on the second stage S2, the pressure applied to the molten resin is greater than the pressure applied to the molten resin in the second stage S2. As a result, the molten resin (molten resin with additives mixed in) can be mixed even more efficiently and in a shorter time, and the additives can be dispersed, compared to the second stage S2.

[0047] Furthermore, the molten resin (molten resin mixed with additives) transferred from the second stage S2 passes through the upstream flight groove (flight groove 74 in the range indicated by the symbol A5 in Figure 9), merges at the first notch 75, is distributed to the intermediate flight groove (flight groove 74 in the range indicated by the symbol A6 in Figure 9), passes through the intermediate flight groove, merges at the second notch 76, is distributed to the downstream flight groove (flight groove 74 in the range indicated by the symbol A7 in Figure 9), and is then transferred downstream by passing through the downstream flight groove.

[0048] Thus, in the mixing piece 70, the molten resin (molten resin with additives mixed in) transferred from the second stage S2 merges and is distributed each time it passes through the first notch 75 and the second notch 76, allowing the molten resin (molten resin with additives mixed in) to be mixed more efficiently in a shorter time and the additives to be dispersed.

[0049] As described above, in the mixing piece 70, compared to the second stage S2, the molten resin and additive can be mixed efficiently and in a short time, and the additive can be dispersed. Furthermore, because mixing and dispersion can be performed in a short time, it is possible to suppress the additive (reinforcement resin) from breaking more than necessary in the mixing piece 70.

[0050] The inventors confirmed that using a screw 18 with a kneading piece 70 attached results in a more uniform dispersion of the additive compared to using a screw 18 without a kneading piece 70.

[0051] As described above, according to the embodiment, it is possible to provide a direct molding screw that can knead the molten resin being transported from the upstream side with the additive that is introduced midway through (from the additive inlet 17b formed in the heating cylinder 17) and disperse the additive (reinforcing fiber) more uniformly.

[0052] Furthermore, according to this embodiment, the kneading piece 70 is detachably attached to the downstream end of the screw body 60, so the kneading piece 70 can be replaced with another kneading piece as needed. For example, if the pressure generated by the kneading piece 70 causes the additive to agglomerate and disperse poorly, the kneading piece 70 can be removed and replaced with another kneading piece (not shown) in the shape of a round bar (cylindrical) that omits the flight 73 to reduce pressure loss.

[0053] The present invention has been described in detail above based on embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0054] 1...Injection molding equipment 12 plasticizing units 13… Clamping Unit 14... Bed 15…Base 16... Mechanism section 17…Heating cylinder 17a…Resin inlet 17b…Additive material inlet 17c…Inner wall 18…Molding screw 19…Injection nozzle 20... Hoppa 21… Fixed mold 22…Fixed plate 23... Clamping Cylinder 24...Taiba 24a... Half nut locking part 25…Movable mold 26…Movable plate 27... Half nut 28-type servo motor for opening and closing 29…Mold opening / closing mechanism 30...Control device 31...Operating device 32...Display device 60... Screw body 61…Main Flight 62… Flight groove 63... Secondary Flight 64... Step section Flights 65, 66… 67… Flight groove 70… Mixed pieces 71... Mixing Piece Main Body 72... Threaded part 73... Flight 74… Flight groove 75...First notch 76...Second notch A1…Supply section A2... Compression section A3...Measuring part A4…Hunger Zone S1…Stage 1 S2…Stage 2 θ1…Lead angle θ2…Lead angle

Claims

1. A direct molding screw that melts a thermoplastic resin supplied from the upstream side and transfers it to the downstream side, and kneads the molten resin being transferred with an additive that is added along the way, The screw body and The screw body is detachably attached to the downstream end, and comprises a kneading piece body, The screw body includes a first stage located on the upstream side and a second stage located on the downstream side. The outer surface of the first stage is provided with a spiral main flight, Multiple spiral-shaped flights are provided on the outer surface of the second stage. The outer surface of the kneading piece body is provided with multiple spiral-shaped flights. A direct molding screw having at least one notch formed in the middle of the flight provided on the kneading piece body.

2. The direct forming screw according to claim 1, wherein the notches are arranged in an annular manner in the circumferential direction.

3. The direct molding screw according to claim 1 or 2, wherein a stepped portion is formed at the top of the main flight by cutting out the downstream portion of the top of the main flight, allowing molten resin to enter.

4. The outer surface of the first stage is further provided with spiral-shaped secondary flights. The direct forming screw according to any one of claims 1 to 3, wherein the sub-flight branches off from the main flight and rejoins the main flight at the downstream end of the first stage.

5. The direct molding screw according to any one of claims 1 to 4, wherein the axial length of the kneading piece body is shorter than the axial length of the screw body.

6. The direct molding screw according to any one of claims 1 to 5, wherein the number of flights provided on the kneading piece body is greater than the number of flights provided on the second stage.

7. The direct molding screw according to any one of claims 1 to 6, wherein the lead angle of the flight provided on the kneading piece body is greater than the lead angle of the flight provided on the second stage.

8. The direct molding screw according to any one of claims 1 to 7, wherein the groove depth of the flight groove defined by the flight provided on the kneading piece body is shallower than the groove depth of the flight groove defined by the flight provided on the second stage.

9. An injection molding apparatus comprising a direct molding screw according to any one of claims 1 to 8.

10. The device includes a mixing piece body that is detachably attached to the downstream end of a direct molding screw that melts and transports thermoplastic resin supplied from the upstream side to the downstream side, and mixes the transported molten resin with additives added along the way. The outer surface of the kneading piece body is provided with multiple spiral-shaped flights. A kneading piece having at least one notch formed in the middle of the flight provided on the kneading piece body.

11. The kneading piece according to claim 10, further comprising a threaded portion that is screwed into a threaded hole formed at the downstream end of the screw body.

12. An injection molding apparatus comprising a direct molding screw, the kneading piece according to claim 10 or 11, which is detachably attached to the downstream end.

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