Injection molding machine

Abstract

To provide an injection molding machine that can prevent vent-up without reducing productivity, and can also prevent clogging of the vent opening, thereby stabilizing product quality. [Solution] The injection molding machine 1 comprises a screw 10, a barrel 20 having an inlet 22 for feeding resin material 2 into a cylinder 21, a vent port 23 provided in the supply section 21a of the cylinder 21 where the resin material 2 is in an unmelted state, and a gas inlet 24 provided downstream of the vent port 23, an air supply device 30 that constantly supplies air supply gas G to the gas inlet 24 during continuous molding, and a ventilation member 40 that prevents resin material 2 from entering the gas inlet 24 from the cylinder 21 of the barrel 20. The barrel 20 is configured to exhaust the generated vapor V produced when the resin material 2 is melted in the cylinder 21 by utilizing the gas flow F when the air supply gas G flows to the vent port 23.

Description

Technical Field

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[0001] The present invention relates to an injection molding machine.

Background Art

[0002] The following Patent Document 1 discloses a conventional vent type injection molding machine. This vent type injection molding machine includes a screw provided in a cylinder and a vent portion. The vent portion is provided in a compression melting portion which is the second stage of the screw, and has a vent port formed to open upward. According to this vent portion, water vapor and volatile components generated from the molten resin material can be discharged from the vent port.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above injection molding machine, when the supply amount of the resin material to the cylinder becomes too large or the back pressure of the cylinder rises, a phenomenon occurs in which the molten resin overflows from the vent port provided in the compression melting portion, so - called "vent up". Due to vent up, the adjustment of molding conditions for improving product quality such as product dimensions and appearance is restricted. In order to prevent the occurrence of vent up, if the supply amount of the resin material to the cylinder is reduced, then the productivity will decrease as the molding cycle extends.

[0005] Therefore, in the design of this type of injection molding machine, there is a need for technology that can prevent vent-up without reducing productivity. For example, if a structure is adopted in which a vent is provided in the supply section upstream of the compression and melting section (the part where the resin material exists in an unmelted state), vent-up caused by molten resin can be prevented, and there is no need to reduce the amount of resin material supplied to the cylinder. However, if a structure is adopted in which a vent is provided in the supply section, resin residue and other materials may clog the vent, and a problem may arise in which product quality deteriorates due to the clogging of the vent.

[0006] This invention has been made in view of the above problems, and aims to provide an injection molding machine that can prevent vent-up without reducing productivity and prevent clogging of the vent opening, thereby stabilizing product quality. [Means for solving the problem]

[0007] One aspect of the present invention is, An injection molding machine that heats and melts resin material and injects it, A screw having spiral-shaped flights on the outer circumference of the shaft and rotating around the axis of rotation, A barrel having a cylinder through which the screw is inserted, an inlet for feeding the resin material into the cylinder, a vent in the supply section of the cylinder where the resin material is in an unmelted state, and a gas inlet located downstream of the vent in the cylinder, A gas supply unit that continuously supplies air to the gas inlet of the barrel during continuous molding, A ventilation member that has breathability and prevents the resin material from entering the gas inlet from the cylinder of the barrel, Equipped with, The barrel is configured to exhaust the generated vapor produced when the resin material is melted in the cylinder from the vent port by utilizing the gas flow when the supplied gas flows to the vent port, in an injection molding machine. It is located there. [Effects of the Invention]

[0008] In the injection molding machine according to the above embodiment, the barrel is provided with a vent port in the supply section of the cylinder through which the screw is inserted, and a gas inlet is provided downstream of the vent port in the cylinder. Here, the supply section is the part that supplies the resin material fed into the cylinder from the input port in an unmelted state to the compression section downstream. Since the barrel's vent port is open in the supply section, it is possible to prevent vent-up, where molten resin material overflows from the vent port due to the internal pressure of the resin. Therefore, it is not necessary to take measures to reduce the amount of resin material supplied to the cylinder in anticipation of vent-up, and a decrease in productivity can be prevented.

[0009] On the other hand, by providing a gas supply unit that constantly supplies aeration gas to the barrel's gas inlet during continuous molding, the aeration gas introduced into the cylinder through the gas inlet can be continuously flowed to the vent. By utilizing this continuous gas flow, the generated vapor produced from the resin material during melting in the cylinder can be flowed together with the aeration gas to the vent and forcibly exhausted from the vent. This prevents low-boiling point hydrocarbons contained in the generated vapor from condensing and clogging the vent with resin residue, thus preventing deterioration of product quality due to vent clogging. Furthermore, by providing a ventilation member that prevents resin material from entering the gas inlet from the barrel's cylinder, clogging of the gas inlet can be prevented, and the continuous supply of aeration gas to the cylinder can be maintained.

[0010] According to the above-described embodiment, it becomes possible to provide an injection molding machine that can prevent vent-up without reducing productivity and prevent clogging of the vent opening, thereby stabilizing product quality. [Brief explanation of the drawing]

[0011] [Figure 1] Cross-sectional view of the injection molding machine of Embodiment 1. [Figure 2] A cross-sectional view showing an enlarged view of section A of the injection molding machine in Figure 1. [Figure 3] Cross-sectional view for explaining the relationship between the arrangement region of the gas inlet and the displacement region at the boundary between the supply part and the compression part in FIG. 2. [Figure 4] Cross-sectional view of the injection molding machine of Embodiment 2. [Figure 5] Cross-sectional view of the injection molding machine of Embodiment 3.

MODE FOR CARRYING OUT THE INVENTION

[0012] Preferred embodiments of the above aspects will be described below.

[0013] In the injection molding machine of the above aspect, it is preferable that the vent port of the barrel is provided at an arbitrary intermediate position excluding the inlet between the inlet and the gas inlet in the supply part of the cylinder.

[0014] According to this injection molding machine, by providing the vent port of the barrel at an arbitrary intermediate position excluding the inlet between the inlet and the gas inlet, it is possible to exhaust from the vent port under conditions where the generated vapor generated during melting from the resin material in the cylinder is difficult to condense.

[0015] In the injection molding machine of the above aspect, a cooling device for cooling the resin material introduced into the supply part of the cylinder is provided near the inlet of the barrel, and it is preferable that the vent port of the barrel is provided at a position that does not overlap with the cooling device in the radial direction of the screw.

[0016] According to this injection molding machine, considering that the temperature of the part near the inlet of the barrel becomes low due to the cooling effect of the cooling device and the generated vapor is likely to condense, by providing the vent port at a position that does not overlap with the cooling device in the radial direction of the screw, it is possible to exhaust from the vent port under conditions where the generated vapor generated during melting from the resin material in the cylinder is difficult to condense.

[0017] In the injection molding machine of the above aspect, it is preferable that the vent port of the barrel has a diameter that blocks the passage of the resin material.

[0018] According to this injection molding machine, since the diameter of the vent port is a diameter that blocks the passage of the resin material and there is no need to provide a dedicated structure to prevent the resin material from entering the vent port, the structure of the vent port can be simplified.

[0019] In the injection molding machine of the above aspect, the screw has a compression part that compresses the resin material supplied from the supply part of the cylinder, and the boundary part between the supply part and the compression part is configured to be displaced in the axial direction of the screw as the screw moves during continuous molding. The barrel is configured such that a plurality of gas inlets are arranged at intervals in the axial direction, and the arrangement region of the gas inlets preferably overlaps with part or all of the displacement region of the boundary part when viewed from the radial direction of the screw.

[0020] According to this injection molding machine, considering that the boundary part between the supply part and the compression part of the cylinder is displaced in the axial direction as the screw moves during continuous molding, by making the arrangement region of the gas inlets overlap with part or all of the displacement region of the boundary part, the supply gas can always be introduced through the gas inlets near the compression part regardless of the displacement of the boundary part in the axial direction. Thereby, the generated vapor generated during melting from the resin material in the cylinder can be surely flowed to the vent port together with the supply gas.

[0021] Hereinafter, a specific example of an embodiment of the injection molding machine of the above aspect will be described while referring to the drawings.

[0022] In the drawings used in the description of this embodiment, unless otherwise specified, the axial direction of the screw constituting the injection molding machine is indicated by arrow X, and the radial direction of this screw is indicated by arrow Y.

[0023] (Embodiment 1) The injection molding machine 1 of Embodiment 1, shown in Figure 1, is a device for heating, melting (plasticizing), and injecting granular or pelletized resin material 2. This injection molding machine 1 comprises a screw 10, a barrel 20, an air supply device 30, a ventilation member 40, a heating device 50, and a cooling device 60. This injection molding machine 1 is used with the screw 10 positioned horizontally. The resin material 2 is a material that generates high-boiling-point volatile gases when melted.

[0024] 1. Structure of Screw 10 As shown in Figure 1, the screw 10 has a helical flight 12 on the outer circumference of the shaft portion 11. The shaft portion 11 extends linearly in the axial direction X. The flight 12 extends helically. This forms a groove between the shaft portion 11 and the flight 12 that extends in the helical direction, through which the resin material 2 moves. One end of the shaft portion 11 (the right end in Figure 1) is a coupling 11a connected to a drive device (not shown). The screw 10 becomes rotatable around the rotation axis L and reciprocating along the rotation axis L when the coupling 11a of the shaft portion 11 is connected to the drive device.

[0025] 2. Structure of the barrel 20 As shown in Figure 1, the barrel 20 has a cylinder 21, an inlet 22, a vent 23, and a gas inlet 24. The cylinder 21 of the barrel 20 is an internal space through which the screw 10 is inserted in the axial direction X. The screw 10 is housed in this cylinder 21 so as to be rotatable about the axis of rotation L and so as to be able to reciprocate along the axis of rotation L.

[0026] In this configuration of cylinder 21, the resin material 2 is fed from the input port 22 side in the material feeding direction D as the screw 10 moves. Therefore, the input port 22 side of cylinder 21 (right side in Figure 1) is the upstream side in the material feeding direction D, and the opposite side (left side in Figure 1) is the downstream side in the material feeding direction D.

[0027] Here, the cylinder 21 has a supply section 21a, a compression section 21b, and a metering section 21c. The compression section 21b is formed downstream of the supply section 21a in the material feeding direction D, and the metering section 21c is formed downstream of the compression section 21b in the material feeding direction D (the furthest downstream of the screw 10). Note that each of these sections is formed between the cylinder 21 and the screw 10 that is inserted through it. Therefore, it can also be said that the screw 10 has each of these sections (supply section 21a, compression section 21b, and metering section 21c).

[0028] The supply section 21a is the upstreammost part of the cylinder 21 in the material feeding direction D. In this supply section 21a, the unmolten resin material 2, which is fed into the cylinder 21 from the inlet 22 of the barrel 20, is supplied quantitatively and continuously to the compression section 21b by the rotation of the screw 10 around its rotation axis L. In addition, in this supply section 21a, because the resin material 2 is unmolten and bulky, the outer diameter of the shaft portion 11 of the screw 10 is narrower than that of the compression section 21b (i.e., the groove depth of the screw 10 is deeper).

[0029] Furthermore, in order to maintain the unmelted state of the resin material 2, the temperature conditions of the supply unit 21a are set to be below the melting temperature of the resin material 2. With such temperature conditions, only water, which has a lower boiling point than volatile gases, is generated from the unmelted resin material 2 in the supply unit 21a. As the unmelted resin material 2 passes through the supply unit 21a, deformation progresses. At this time, shear heat is imparted to the resin material 2, and the surface area of ​​the resin material 2 increases due to its deformation. This promotes the discharge of water from the resin material 2. Alternatively, by adjusting molding conditions such as the supply rate of the resin material 2, the temperature conditions may be set to be above the melting temperature.

[0030] In the compression section 21b, the resin material 2 supplied from the supply section 21a of the cylinder 21 is heated and compressed, causing it to melt. Therefore, this compression section 21b is also called the "compression melting section." This compression section 21b is a zone where the outer diameter of the shaft portion 11 of the screw 10, which continues from the supply section 21a, gradually expands (i.e., the groove depth of the screw 10 gradually becomes shallower). In order to melt the resin material 2, the temperature conditions in the compression section 21b are set to exceed the melting temperature of the resin material 2.

[0031] In the metering section 21c, the resin material 2 that has been melted in the compression section 21b of the cylinder 21 is measured. This metering section 21c is a zone where the outer diameter of the shaft portion 11 of the screw 10, which continues from the compression section 21b, is constant (i.e., the groove depth of the screw 10 is constant).

[0032] The input port 22 is an opening provided through the barrel 20 for feeding the resin material 2 into the supply section 21a of the cylinder 21. A hopper (not shown) to which the resin material 2 is supplied is connected to the top of this input port 22. The resin material 2 supplied to the hopper is fed into the supply section 21a of the cylinder 21 through the input port 22 by gravity.

[0033] The vent port 23 is provided in the supply section 21a of the cylinder 21. In this embodiment, the vent port 23 is provided at any intermediate position P of the supply section 21a of the cylinder 21, between the inlet port 22 and the gas inlet port 24, excluding the inlet port 22. The intermediate position P is also a position that does not overlap with the cooling device 60 in the radial direction Y. This vent port 23 is an opening provided through the barrel 20. This vent port 23 is opened so as to connect the supply section 21a of the cylinder 21 to the outside. In the figure, this vent port 23 is shown opening upwards, but it does not necessarily have to be upwards. This vent port 23 is a through-hole with a circular cross-sectional shape and a diameter d1 that prevents the resin material 2 from passing through. The diameter d1 is sized to be less than the minimum particle size of the unmelted resin material 2. This prevents the resin material 2 from entering the vent port 23 from the supply section 21a of the cylinder 21 and escaping to the outside.

[0034] The gas inlet 24 is located downstream of the vent port 23 in the supply section 21a of the cylinder 21 (in Figure 1, it is located to the left of the vent port 23). Similar to the vent port 23, the gas inlet 24 is a through-hole in the barrel 20. In this embodiment, four gas inlets 24 are provided. The four gas inlets 24 are located in the supply section 21a of the cylinder 21, similar to the vent port 23, and are spaced apart in the axial direction X. The four gas inlets 24 are circular through-holes with the same cross-sectional dimensions and a diameter d2. In this embodiment, the diameter d2 of the gas inlet 24 only needs to ensure sufficient airflow to prevent clogging, and is sized to be smaller than the diameter d1 of the vent port 23. Note that the number of gas inlets 24 is not limited to four; an appropriate number can be used as needed.

[0035] Although not specifically shown in the diagram, the tip of the barrel 20 (the leftmost part in Figure 1) is provided with a nozzle for injecting the molten resin material 2 into a mold located outside the cylinder 21.

[0036] 3. Structure of the air supply device 30 As shown in Figure 1, the air supply device 30 is a gas supply unit that constantly supplies air, which is the supply gas G, to the four gas inlets 24 of the barrel 20 during continuous molding. The air supply device 30 is connected to each of the four gas inlets 24 of the barrel 20 via each of the four connecting pipes 31. Therefore, the supply gas G supplied from the air supply device 30 flows into each gas inlet 24 through each connecting pipe 31. The supply gas G then flows through each gas inlet 24 and is introduced into the supply unit 21a of the cylinder 21.

[0037] 4. Structure of the ventilation member 40 As shown in Figure 1, the ventilation member 40 is built into the cylinder 21 side of each gas inlet 24. This ventilation member 40 has permeability and is configured to prevent the resin material 2 from entering the gas inlet 24 from the supply section 21a of the cylinder 21 of the barrel 20. With this ventilation member 40, it is possible to allow the supplied gas G to be introduced into the supply section 21a of the cylinder 21 through each gas inlet 24, while preventing the resin material 2 from entering from the supply section 21a of the cylinder 21. For example, a filter member made of stainless steel or ceramic material can be used as the ventilation member 40.

[0038] 5. Structure of the heating device 50 As shown in Figure 1, the heating device 50 is a heater provided on the outer circumference of the barrel 20. Multiple heating devices 50 are provided in the radially outward region of the cylinder 21, corresponding to the supply section 21a, compression section 21b, and metering section 21c of the barrel 20, respectively. With this heating device 50, the supply section 21a, compression section 21b, and metering section 21c of the barrel 20 can be heated by the heat generated from the heater.

[0039] Note that the location where the heating device 50 is installed is not limited to that shown in Figure 1, and can be changed as needed. The heating device 50 installed at the position corresponding to the supply section 21a of the barrel 20 is preferably controlled to maintain the resin material 2 in the supply section 21a in an unmelted state. The heating device 50 may be omitted if necessary.

[0040] 6. Structure of the cooling device 60 As shown in Figure 1, the cooling device 60 is located near the inlet 22 of the barrel 20. This cooling device 60 has the function of cooling the resin material 2 that is fed into the supply section 21a of the cylinder 21. In this embodiment, the cooling device 60 has a refrigerant flow path 61 through which a cooling medium flows, and is configured as a jacket-type cooler that cools the area near the inlet 22 by heat exchange with this cooling medium. This cooling device 60 can suppress the formation of bridges by solidifying the resin material 2 near the inlet 22. If necessary, a structure other than a jacket-type cooler may be adopted for the structure of the cooling device 60.

[0041] 7. Exhaust treatment Next, the exhaust treatment in the cylinder 21 of the barrel 20 will be described with reference to Figures 2 and 3.

[0042] As shown in Figure 2, during continuous molding by the injection molding machine 1, air supply gas G is constantly supplied from the air supply device 30 to the four gas inlets 24 of the barrel 20. As a result, air supply gas G is constantly introduced into the cylinder 21 of the barrel 20 through each gas inlet 24. At this time, the air supply gas G is introduced into the cylinder 21 in a heated state through heat exchange with the barrel 20, which is heated by the heating device 50. In this embodiment, since each gas inlet 24 has a built-in ventilation member 40, the air supply gas G can be continuously introduced into the cylinder 21 without allowing the resin material 2 from the cylinder 21 to enter each gas inlet 24.

[0043] The supplied gas G introduced into cylinder 21 flows upstream (to the right in Figure 2). This is because the packing density of the resin material 2 gradually decreases as it approaches the inlet 22 located upstream in cylinder 21. Therefore, the supplied gas G flows through cylinder 21 to the vent port 23 on the upstream side. At this time, the gas flow F of the supplied gas G not only directly pushes the generated vapor V produced from the resin material 2 in the compression section 21b toward the vent port 23, but also draws the generated vapor V toward the vent port 23.

[0044] Thus, by utilizing the gas flow F of the supplied gas G, the generated steam V is carried to the vent port 23 and exhausted from the vent port 23. The generated steam V is the steam generated when the resin material 2 melts in the compression section 21b. This generated steam V contains water and volatile substances. In addition, the water generated in the supply section 21a of the cylinder 21 is also exhausted from the vent port 23 according to the gas flow F of the supplied gas G. By discharging water to the outside from the cylinder 21, the drying process of the resin material 2 can be efficiently carried out in the barrel 20. As a result, a pre-drying process to dry the resin material 2 before introducing it into the input port 22 is unnecessary, and the energy required for the drying process can be kept low.

[0045] The properties of the supplied gas G from the air supply device 30 are preferably high temperature and highly dry, based on conditions such as the dew point of the generated vapor V. This allows the generated vapor V to be removed from the cylinder 21 while remaining in gaseous form and minimizing condensation.

[0046] As shown in Figure 3, the barrel 20 in this embodiment is configured such that the boundary portion 25 between the supply portion 21a and the compression portion 21b is displaced axially in accordance with the movement of the screw 10 (movement of one cycle) during continuous molding by the injection molding machine 1. Furthermore, the barrel 20 is configured such that the arrangement area R1 of the four gas inlets 24 overlaps with a part of the displacement area R2 of the boundary portion 25 when viewed from the radial direction Y. If necessary, the arrangement area R1 of the four gas inlets 24 may be made to overlap with the entire displacement area R2 of the boundary portion 25.

[0047] With this configuration, even though the boundary 25 between the supply section 21a and the compression section 21b of the cylinder 21 is displaced in the axial direction X due to the movement of the screw 10 during continuous molding by the injection molding machine 1, the supply gas G can be continuously introduced near the compression section 21b through the gas inlet 24. As a result, the generated vapor V produced from the resin material 2 during melting in the cylinder 21 can be reliably flowed to the vent port 23 together with the supply gas G.

[0048] 8. Effects According to Embodiment 1 described above, the following effects and advantages can be obtained.

[0049] In the injection molding machine 1 of Embodiment 1, the barrel 20 is provided with a vent port 23 in the supply section 21a of the cylinder 21 through which the screw 10 is inserted, and a gas inlet 24 is provided in the cylinder 21 downstream of the vent port 23. Here, the supply section 21a is the part that supplies the resin material 2, which is fed into the cylinder 21 from the input port 22, to the downstream compression section 21b in an unmelted state. Since the vent port 23 of the barrel 20 is open in the supply section 21a, it is possible to prevent vent-up, where the molten resin material 2 overflows from the vent port 23 due to the internal pressure of the resin. Therefore, it is not necessary to take measures to reduce the amount of resin material 2 supplied to the cylinder 21 in anticipation of vent-up, and a decrease in productivity can be prevented.

[0050] On the other hand, by providing an air supply device 30 that constantly supplies air supply gas G to the gas inlet 24 of the barrel 20 during continuous molding by the injection molding machine 1, the air supply gas G introduced into the cylinder 21 through the gas inlet 24 can be continuously flowed to the vent port 23. By utilizing the continuous gas flow F of the air supply gas G at this time, the generated vapor V produced from the resin material 2 during melting in the cylinder 21 can be flowed together with the air supply gas G to the vent port 23 and forcibly exhausted from the vent port 23. This prevents the low-boiling point hydrocarbons contained in the generated vapor V from condensing and clogging the vent port 23 with resin residue, thus preventing deterioration of product quality due to clogging of the vent port 23. In addition, by providing a ventilation member 40 that prevents the resin material 2 from entering the gas inlet 24 from the cylinder 21 of the barrel 20, clogging of the gas inlet 24 can be prevented and the continuous introduction of air supply gas G to the cylinder 21 can be maintained.

[0051] Therefore, according to Embodiment 1, it is possible to provide an injection molding machine 1 that can prevent vent-up without reducing productivity and prevent clogging of the vent port 23, thereby stabilizing product quality.

[0052] According to the injection molding machine 1, the back pressure of the cylinder 21 of the barrel 20 can be maintained at a high level by preventing vent-up. This improves the kneadability of the resin material 2 in the compression section 21b and reduces variations in the density of the resin material 2. Furthermore, by reducing variations in the density of the resin material 2, it becomes possible to ensure the desired dimensional accuracy and appearance quality of the product.

[0053] In the injection molding machine 1, the position of the vent port 23 of the barrel 20 is set to an arbitrary intermediate position P between the inlet port 22 and the gas inlet port 24, excluding the inlet port 22. Furthermore, considering that the temperature of the part of the barrel 20 near the inlet port 22 becomes lower due to the cooling effect of the cooling device 60, creating conditions where the generated vapor V is more likely to condense, the intermediate position P is set to a position that does not overlap with the cooling device 60 in the radial direction Y. This makes it possible to exhaust the generated vapor V generated from the resin material 2 during melting in the cylinder 21 through the vent port 23 under conditions where condensation is less likely.

[0054] According to the injection molding machine 1, the diameter d1 of the vent opening 23 is such that it prevents the resin material 2 from passing through, and there is no need to provide a special structure to prevent the resin material 2 from entering the vent opening 23, thus simplifying the structure of the vent opening 23.

[0055] Next, other embodiments related to Embodiment 1 described above will be explained with reference to the drawings. In the other embodiments, elements identical to those in Embodiment 1 are denoted by the same reference numerals, and the explanation of such identical elements will be omitted.

[0056] (Embodiment 2) The injection molding machine 1A of Embodiment 2, shown in Figure 4, differs from the injection molding machine 1 of Embodiment 1 in that a gas inlet 24 is provided in the compression section 21b of the cylinder 21.

[0057] The other structural features are the same as those of Embodiment 1.

[0058] In the injection molding machine 1A of Embodiment 2, by providing a gas inlet 24 in the compression section 21b, which is at a higher temperature than the supply section 21a, the generated vapor V that comes into contact with the ventilation member 40 built into the gas inlet 24 is less likely to condense. This suppresses the condensation of low-boiling point hydrocarbons contained in the generated vapor V, which can clog the ventilation member 40 with resin residue. Furthermore, by providing a gas inlet 24 in the compression section 21b, the function of directly pushing the generated vapor V toward the vent port 23 by the supplied gas G can be enhanced.

[0059] Furthermore, it exhibits the same effects and advantages as in Embodiment 1.

[0060] (Embodiment 3) The barrel 20 of the injection molding machine 1B of Embodiment 3, shown in Figure 5, differs from the structure of the injection molding machine 1 of Embodiment 1 in that the function of the vent port 23 of the cylinder 21 is also served by the inlet port 22. In this configuration, the generated steam V produced from the resin material 2 in the compression section 21b is carried to the inlet port 22 and exhausted from the inlet port 22.

[0061] The other structural features are the same as those of Embodiment 1.

[0062] According to the injection molding machine 1B of Embodiment 3, there is no need to provide a dedicated vent port 23 in the barrel 20, and the structure of the barrel 20 can be simplified accordingly.

[0063] Furthermore, it exhibits the same effects and advantages as in Embodiment 1.

[0064] As a particularly relevant modification to Embodiment 3, a gas inlet 24 may be provided in the compression section 21b of the cylinder 21, as in Embodiment 2.

[0065] 9. Other forms The present invention is not limited to the typical embodiments described above, and various applications and modifications are conceivable as long as they do not depart from the purpose of the invention. For example, the following embodiments can be implemented by applying the embodiments described above.

[0066] In the above-described configuration, the example shown was the use of air as the supplying gas G. However, the supplying gas G is not limited to air, and other gases may be used as needed. For example, when using a resin material 2 that is sensitive to oxidation, an inert gas such as nitrogen can be used instead of air. [Explanation of Symbols]

[0067] 1,1A,1B…Injection molding machine, 2…Resin material, 10…Screw, 11…Shaft, 12…Flight, 21…Cylinder, 21a…Supply unit, 21b…Compression unit, 22…Inlet, 23…Vent, 24…Gas inlet, 25…Boundary, 30…Air supply device (gas supply unit), 40…Ventilation member, 60…Cooling device, d1…Port diameter, F…Gas flow, G…Supply gas, L…Rotation axis, P…Intermediate position, R1…Placement area, R2…Displacement area, V…Generated vapor, X…Axial direction, Y…Radial direction

Claims

1. An injection molding machine that heats and melts resin material and injects it, A screw having spiral-shaped flights on the outer circumference of the shaft and rotating around the axis of rotation, A barrel having a cylinder through which the screw is inserted, an inlet for introducing the resin material into the cylinder, a vent in the supply section of the cylinder where the resin material is in an unmelted state, and a gas inlet located downstream of the vent in the cylinder, A gas supply unit that continuously supplies air to the gas inlet of the barrel during continuous molding, A ventilation member that has breathability and prevents the resin material from entering the gas inlet from the cylinder of the barrel, Equipped with, An injection molding machine in which the barrel is configured to exhaust the generated vapor produced when the resin material is melted in the cylinder from the vent port by utilizing the gas flow when the supplied gas flows to the vent port.

2. The injection molding machine according to claim 1, wherein the vent port of the barrel is provided at any intermediate position between the inlet port and the gas inlet port in the supply section of the cylinder, excluding the inlet port.

3. A cooling device is provided near the input port of the barrel to cool the resin material that has been fed into the supply section of the cylinder. The injection molding machine according to claim 1, wherein the vent port of the barrel is provided in a position that does not overlap radially with the cooling device and the screw.

4. The injection molding machine according to any one of claims 1 to 3, wherein the vent opening of the barrel has a diameter that prevents the passage of the resin material.

5. The screw has a compression section that compresses the resin material supplied from the supply section of the cylinder, and is configured such that the boundary between the supply section and the compression section is displaced in the axial direction of the screw as the screw moves during continuous molding. The injection molding machine according to any one of claims 1 to 3, wherein the barrel has a plurality of gas inlets arranged at intervals in the axial direction, and the arrangement area of ​​the gas inlets is configured such that, when viewed from the radial direction of the screw, it overlaps with part or all of the displacement area of ​​the boundary.

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