JP6594284B2 - Operation method of plasticizing injection device - Google Patents

Description

  The present invention provides a plasticizing device for melting a resin, an injection device for measuring and injecting the molten resin, an injection portion such as an injection nozzle for injecting the resin, and connecting a resin flow path. The present invention relates to a method of operating a plasticizing injection apparatus comprising a flow path switching device adapted to be switched.

The injection device can be roughly classified into an inline screw type and a plunger type. There are various types of plunger type, and there is also a plunger type injection device in which resin plasticization and injection are performed in the same device, and resin plasticization is performed in separate devices. There are also plunger-type injection devices that only perform injection. In the former plunger type injection device, since the plunger and the melter are integrated and plasticization and injection can be performed in the injection device, it is not necessary to receive the supply of molten resin from an external device. A switching valve for switching the flow path is not particularly required. That is, it can be configured simply. However, when the resin is melted, it is necessary to drive the plunger, and it is difficult to increase the size of the melter, so the melting efficiency is relatively low. On the other hand, in the latter plunger type injection device, plasticization is performed by a plasticizing device which is another device, the resin plasticized by this plasticizing device is metered into a plunger type injection device by a predetermined amount, After that, it comes to inject. Since the melting and injection of the resin are performed by separate apparatuses, the melting efficiency can be increased. Such a latter plunger type injection device comprises a plasticizing device for plasticizing a resin and an injection device for injecting the resin, and these can be collectively referred to as a plasticizing injection device. There are various configurations of the plasticizing injection apparatus, but a configuration capable of continuously melting the resin in the plasticizing apparatus is also well known. For example,
Patent Documents 1 and 2 propose a plasticizing injection apparatus capable of continuously melting the resin in this way.

Japanese Patent No. 3062629 Japanese Patent No. 2786243

  As shown in FIG. 5A, a plasticizing injection device 51 described in Patent Document 1 includes a plasticizing device 52 that melts a resin, an accumulator device 53 that temporarily stores the molten resin, And an injection device 54 for injecting molten resin. The plasticizing device 52 includes a heating cylinder 56 and a screw 57, and the resin supplied from the hopper 58 is melted and sent forward. The accumulator device 53 includes a cylinder 60 and a plunger 61 driven in the axial direction, and the resin melted in the plasticizing device 52 is supplied to the cylinder 60. The injection device 54 includes an injection cylinder 63 and an injection plunger 64 driven by a predetermined driving device, and an injection nozzle 65 is provided at the tip of the injection cylinder 63. The resin stored in the accumulator device 53 is supplied into the injection cylinder 63 through a flow path, and a first opening / closing valve 67 is interposed in the flow path. A second opening / closing valve 68 is interposed in the resin flow path in the injection cylinder 63 communicating with the injection nozzle 65. In this plasticizing injection device 51, the plasticizing device 52 is continuously plasticized without being interrupted even in the injection process and the pressure holding process, and its operation method will be described. . First, the first on-off valve 67 is closed, and the resin flow path between the accumulator device 53 and the injection device 54 is shut off. Then, the resin plasticized in the plasticizing device 52 is supplied to the cylinder 60 of the accumulator device 53. The plunger 61 is retracted by the pressure of the resin, and the resin is accumulated. When an amount slightly smaller than the amount of resin required for one injection is accumulated, the first on-off valve 67 is opened and the second on-off valve 68 is closed. Then, the plunger 61 is driven in the axial direction. Then, resin is supplied to the injection cylinder 63 of the injection device 54, and the injection plunger 64 moves backward. At this time, since the plasticizing device 52 continues plasticizing, the resin from the plasticizing device 52 is also supplied to the injection device 54. When the plunger 61 reaches the stop position, that is, the extrusion completion position, this state is maintained for a while. Then, the resin from the plasticizing device 52 is continuously supplied to the injection device 54. When the required amount of resin is measured in the injection device 54, the first opening / closing valve 67 is closed. When the second opening / closing valve 68 is opened and the injection plunger 64 is driven, the resin is injected. A predetermined axial force is applied to the injection plunger 64 until the pressure holding process is completed. By the way, immediately after the first opening / closing valve 67 is closed, the resin melted by the plasticizing device 51 is sent to the accumulator device 53 and the accumulation of the resin is started. This resin is used for the next injection, and can be continuously plasticized in the plasticizer 51. Thereafter, the same operation is performed.

  As shown in FIG. 5A, a plasticizing injection device 71 described in Patent Document 2 includes a plasticizing device 72 that melts a resin, and first and second injection devices that inject the molten resin. 73, 74. The plasticizing device 72 includes a heating cylinder 76 and a screw 77, and melts the resin supplied from the hopper 78. The first and second injection devices include injection cylinders 80 and 81, an injection plunger. 82, 83, and the resin melted in the plasticizer 72 is weighed and injected. In this plasticizing injection device 71, a flow path switching valve 85 is provided at the tip of the plasticizing device 72, and two resin flow paths from this flow path switching valve 85, that is, first and second resin supply flow paths 86. , 87 and connected to the first and second injection devices 73, 74. Depending on the switching position of the flow path switching valve 85, one of the first and second resin supply flow paths 86, 87 communicates with the plasticizing device 72 and the other is blocked. In this plasticizing injection device 71, the resin injected from the first and second injection devices 73 and 74 is injected from the injection nozzle 91 via the first and second injection flow paths 89 and 90. However, first and second on-off valves 93 and 94 are interposed in the first and second injection flow paths 89 and 90, respectively. A method for operating the plasticizing injection apparatus 71 will be described. First, in a state where the first on-off valve 93 is closed, the flow path switching valve 85 is operated to cause the plasticizer 72 and the first resin supply flow path 86 to communicate with each other. Then, the resin plasticized and melted by the plasticizing device 72 is supplied to the first injection device 73, and the injection plunger 82 moves backward. When the predetermined amount is measured, the flow path switching valve 85 is operated to cause the plasticizer 72 and the second resin supply flow path 87 to communicate with each other. That is, the first resin supply channel 86 is blocked. At this time, the second on-off valve 94 is closed in advance. Then, the resin plasticized by the plasticizing device 52 is supplied to the second injection device 74, and the measurement is started in the second injection device 74. The first on-off valve 93 is opened, and the injection plunger 82 is driven in the first injection device 73 to perform the injection process. After injection, a pressure holding process is performed for a predetermined time, and the first on-off valve 93 is closed. While the first injection device 73 performs the injection process and the pressure holding process, the second injection device 74 measures the necessary resin. When the metering is completed, the flow switching valve 85 is operated to connect the plasticizing device 72 and the first resin supply flow path 86. As a result, the metering in the first injection device 73 starts. The second opening / closing valve 94 is opened, and the injection plunger 83 of the second injection device 74 is driven to perform the injection process. After performing the pressure holding process for a predetermined time, the second on-off valve 94 is closed. When the necessary resin is metered in the first injection device 73, the flow path switching valve 86 is switched. Thereafter, the same operation is performed.

  Both the plasticizing injection apparatus 51 described in Patent Document 1 and the plasticizing injection apparatus 71 described in Patent Document 2 can continuously plasticize the resin in the plasticizing apparatuses 52 and 72. Therefore, the effect that the quality of the molten resin is kept constant can be obtained. Since the plasticizing process is not interrupted by the injection process and the pressure holding process, the cycle time of the molding cycle can be shortened, which is excellent. However, there are also problems to be solved. First, as a problem to be solved in the plasticizing injection apparatuses 51 and 71 described in Patent Documents 1 and 2, the flow path switching mechanism for switching the resin flow path can be complicated. The flow path switching mechanism includes a valve, that is, a valve and a plurality of flow paths. In the plasticizing injection apparatus 51, a flow path switching mechanism is constituted by the first and second on-off valves 67 and 68 and the flow path opened in the injection cylinder 63. In the plasticizing injection apparatus 71, the flow path switching mechanism is configured. The switching valve 85, the first and second on-off valves 93 and 94, the first and second resin supply channels 86 and 87, and the first and second injection channels 89 and 90 constitute a channel switching mechanism. . That is, there is a problem that the flow path switching mechanism is complicated and the manufacturing cost is high. In these flow path switching mechanisms, since there are two or more valves and there are many movable parts, the frequency of failure is high. Since the flow path switching mechanism is complicated, there is also a problem that the maintenance cost is high.

  By the way, if the configuration of the flow path switching mechanism is devised, it is likely that the flow path switching mechanism can be simplified and the maintenance cost can be reduced. Specifically, a flow rate switching device including first to fourth connection flow paths and one flow path switching valve is prepared. The flow path switching valve can take two positions. When the first position is set, the first connection flow path and the second connection flow path communicate with each other, and the third connection flow path and the fourth connection flow path. The connection flow path is communicated. When the flow path switching valve is set to the second position, the first connection flow path and the fourth connection flow path communicate with each other, and the second connection flow path and the third connection flow path communicate with each other. To do. The plasticizing injection device is composed of such a flow switching device, one plasticizing device, first and second injection devices, and an injection unit such as an injection nozzle, and the like. The plasticizing device is the first connection channel, the first injection device is the second connection channel, the second injection device is the fourth connection channel, and the injection part is the third connection channel. Connect to each. In the plasticizing injection apparatus configured as described above, when the flow path switching valve is set to the first position, the resin plasticized by the plasticizing apparatus is metered into the first injection apparatus. When weighed, set the flow path switching valve to the second position. Since the first injection device and the injection unit communicate with each other, the first injection device is driven to inject the resin. When the flow path switching valve is in the second position, the resin plasticized by the plasticizing device is metered into the second injection device. When the measurement is completed, the flow path switching valve is set to the first position. Then, since the second injection device communicates with the injection portion, the resin is injected from the second injection device. When the flow path switching valve is in the first position, the resin plasticized by the plasticizing device as described above is metered into the first injection device. Thereafter, the same operation can be performed.

  If the plasticizing / injecting apparatus is configured in this way, the resin can be continuously melted in the plasticizing apparatus, and an excellent effect that the flow path switching mechanism is simple and can be provided at a low cost can be obtained. However, in the flow path switching device provided in such a plasticizing injection apparatus, it is expected that a load is applied to the flow path switching valve. Resin plasticized by the plasticizing device is sent to one of the first and second injection devices according to the switching position of the flow path switching valve and weighed, but the resistance and resin flow when the plunger moves backward The resin has a predetermined pressure due to the resistance. Then, a load acts on the valve body constituting the flow path switching valve according to the pressure of the resin. There is no problem when the valve body is stopped, but if the valve body is driven with this load applied, the valve body is worn or damaged.

  The present invention provides a plasticizing injection apparatus that solves the above-mentioned conventional drawbacks or problems, and provides an operation method in which the flow path switching mechanism is not worn or damaged in such a plasticizing injection apparatus. The purpose is to do. Specifically, it can be continuously plasticized without interruption in the injection process and pressure holding process, and the flow path switching mechanism provides a simple plasticizing injection device. An object of the present invention is to provide an operation method capable of preventing wear and damage of a flow path switching mechanism in the apparatus.

In order to achieve the above object, the present invention provides a plasticizing device for plasticizing a resin, first and second plunger-type injection devices for measuring and injecting the resin, an injection portion, and one flow path. The present invention is directed to a plasticizing injection apparatus including a flow path switching device provided with a switching valve. In this plasticizing injection device, when the flow path switching valve is switched to the first position, the resin melted in the plasticizing device is metered to the first injection device, and the second injection device communicates with the injection portion for injection. By switching to the second position, the resin melted by the plasticizing device is metered to the second injection device, and the first injection device can communicate with the injection portion and inject. ing. When the target resin is a resin containing carbon fiber in such a plasticizing injection apparatus, when the flow path switching valve is switched to the injection apparatus after completion of metering, the plunger is moved backward in the first and second injection apparatuses, etc. Thus, the pressure of the resin in the flow path switching device applied from the plasticizing device is reduced.

That is, in order to achieve the above object, the invention according to claim 1 includes a flow path switching device including first to fourth connection flow paths and one flow path switching valve, and the first connection. A plasticizing device connected to a flow path, a plunger type injection device connected to the second connection flow path, and an injection part connected to the third connection flow path, When the flow path switching valve is switched to the first position, the first connection flow path and the second connection flow path communicate with each other, and the third connection flow path and the fourth connection flow path communicate with each other. Resin melted in the plasticizing device is measured by the injection device, and when the flow path switching valve is switched to the second position, the first connection flow path and the fourth connection flow are set. In addition, the second connection flow path and the third connection flow path are in communication with each other, and the second plastic connection device and the third connection flow channel communicate with each other in the plasticizing apparatus. Wherein the plasticizing injection apparatus resin is adapted to be emitted from the exit portion of the injection apparatus, the resin of the subject and the resin containing carbon fibers with the resin flows into the fourth connecting channel In this case, when the flow path switching valve is switched to the injection apparatus after completion of metering, the pressure of the resin in the flow path switching apparatus applied from the plasticizing apparatus is reduced, and then the plastic switching is performed. It is comprised as an operating method of a chemical injection apparatus.
The invention described in claim 2 is the operation method of the plasticizing injection apparatus according to claim 1, wherein the pressure of the resin in the flow path switching device is reduced by a plunger provided in the injection device. The operation method of the plasticizing injection apparatus is characterized in that it is carried out by forcibly retreating by a predetermined stroke.
According to a third aspect of the present invention, in the operation method of the plasticizing injection apparatus according to the first or second aspect, the plasticizing injection apparatus includes another injection device connected to the fourth connection flow path. When the flow path switching valve is switched to the second position, the resin melted in the plasticizing apparatus is metered to the other injection apparatus, and the flow path switching valve is moved to the first position. When the position is switched, the resin from the other injection device is injected from the injection portion, and when the flow path switching valve is switched to the other injection device after completion of measurement, the resin is applied from the plasticizing device. The operation method of the plasticizing injection apparatus is characterized in that the pressure of the resin in the flow path switching apparatus is reduced and then switched.
According to a fourth aspect of the present invention, in the method of operating a plasticizing injection device according to the third aspect, the pressure of the resin in the flow path switching device is reduced in the other injection device. The operation method of the plasticizing injection apparatus is characterized in that the plunger is forcedly moved backward by a predetermined stroke.

As described above, the present invention is configured as a method for operating a plasticizing injection apparatus having a predetermined configuration. That is, the plasticizing injection apparatus includes a flow path switching device including first to fourth connection flow paths and one flow path switching valve, a plasticizing apparatus connected to the first connection flow path, The plunger-type injection device connected to the two connection flow paths and the injection section connected to the third connection flow path, the first connection when the flow path switching valve is switched to the first position. The flow path and the second connection flow path communicate with each other, and the third connection flow path and the fourth connection flow path communicate with each other so that the molten resin in the plasticizing apparatus is measured by the injection apparatus. When the flow path switching valve is switched to the second position, the first connection flow path and the fourth connection flow path communicate with each other, and the second connection flow path and the third connection flow path communicate with each other. The molten resin flows in the fourth connection flow path and the resin from the injection device is injected from the injection portion. In the plasticizing injection apparatus configured as described above, another injection apparatus may be connected to the fourth connection flow path, or a discharge portion for simply discharging the resin may be provided. In the former case, the resin melted in the plasticizing device is alternately metered between the injection device and other injection devices by switching the flow path switching valve, so that the plasticizing device can continuously melt the resin. Also in the latter case, the resin melted in the plasticizing device is measured by the injection device or discharged from the discharge unit, so that the plasticizing device can continuously melt the resin. In any case, since the resin can be continuously melted, deterioration of the resin can be prevented, and the quality of the resin can be maintained constant. The plasticizing apparatus is simple because the flow path switching device includes only one flow path switching valve and has only one movable part, and an effect that the apparatus can be provided at low cost is obtained. In such a plasticizing injection device, the pressure of the resin acts on the flow path switching valve by the resin melted by the plasticizing device and sent to the injection device. Due to this pressure, an eccentric load is applied to the flow path switching valve. If the flow path switching valve, which is a movable part, is switched in this state, a force is required to operate the flow path switching valve, and the valve body may be worn out. There is also a risk of damage. In the plasticizing injection apparatus of the present invention, when the target resin is a resin containing carbon fiber , the flow path applied from the plasticizing apparatus when the flow path switching valve is switched to the injection apparatus after the completion of measurement. This is configured as an operation method in which the pressure of the resin in the switching device is reduced and then switched . That is, since the flow path switching valve is switched after the pressure of the resin acting on the flow path switching valve is reduced, no force is required for the operation, and the flow path switching valve is not damaged. According to another invention, the pressure of the resin in the flow path switching device is reduced by forcibly retracting the plunger provided in the injection device by a predetermined stroke. Since the pressure of the resin is reduced only by retracting the plunger, the operation is easy and the invention can be implemented at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the plasticization injection apparatus which concerns on embodiment of this invention, The (a) and (b) are respectively the flow-path switching valves of the flow-path switching apparatus concerning this Embodiment. It is sectional drawing which shows the plasticizing injection apparatus when switched to the position of 1,2. It is sectional drawing which shows typically the plasticization injection apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows typically the plasticizing injection apparatus which concerns on the 3rd Embodiment of this invention. It is a figure which shows the flow-path switching apparatus which concerns on other embodiment of this invention, The (a) is a perspective view of a flow-path switching apparatus, The (b) and (c) are the arrow A in the (a), respectively. It is sectional drawing of the flow-path switching apparatus seen by -A and BB. It is a figure which shows a prior art example, (a), (a) is sectional drawing which shows the plasticizing injection apparatus of patent documents 1, 2, respectively.

  Embodiments of the present invention will be described below. As shown in FIG. 1, a plasticizing injection apparatus 1 according to the present embodiment includes a plasticizing apparatus 2 that melts resin, and first and second injection apparatuses 4 and 5 that measure and inject resin. And a flow path switching device 7 that switches the flow path of the resin, and an injection portion 8 that injects the resin. The plasticizing apparatus 2 is composed of a heating cylinder 10 and a screw 11 that rotates in the heating cylinder 10, and the heating cylinder 10 is not shown in the figure, but is heated by a band heater. It has become so. When pellets of material are supplied from the hopper and the screw 11 is rotated, the pellets are melted and sent forward as molten resin. The first and second injection devices 4 and 5 are conventionally known plunger-type injection devices, and include injection cylinders 13 and 14 and plungers 16 and 17 driven in the axial direction in the injection cylinders 13 and 14. It is configured. When the resin is supplied from the plasticizing device 2, the plungers 16 and 17 are moved backward to measure the resin. Injection is possible when the plungers 16 and 17 are driven in the axial direction. The injection unit 8 can be constituted by a die such as a T die, for example, but in the present embodiment, the injection unit 8 includes an injection nozzle 8 and injects resin into a mold.

  The flow path switching device 7 is a flow path switching mechanism that connects the plasticizing device 2, the first and second injection devices 4, 5 and the injection portion 8 and switches the flow path of the resin. It can be said that the plasticizing injection apparatus 1 according to the present embodiment is a characteristic apparatus. The flow path switching device 7 according to the present embodiment is formed in a substantially cubic shape, and a bore 19 is opened vertically from the upper surface of the cube. A valve body 20 to be described next is inserted into the bore 19, and a flow path switching valve 21 is constituted by these. By the way, in the flow path switching device 7, through-holes communicating with the bores 19 from the respective side surfaces are formed on the four side surfaces constituting the cube. That is, the first to fourth connection flow paths 23a, 23b,. These devices are connected to the first to fourth connection flow paths 23a, 23b,. That is, the plasticizing device 2 is in the first connection flow path 23a, the first and second injection devices 4 and 5 are in the second and fourth connection flow paths 23b and 23d, respectively, and the injection nozzle 8 is in the third connection flow. It is connected to the path 23c.

  The valve body 20 has a cylindrical shape, and rotates smoothly in the bore 19. Two grooves having a predetermined length in the circumferential direction are formed on the outer peripheral surface of the valve body 20. These grooves are formed on the same height of the cylinder, and one groove is an arc in the range of 0 to 90 degrees when viewed from the central axis, and the other groove is in the range of 180 to 270 degrees. It is formed in the outer peripheral surface of the valve body 20 by predetermined depth so that it may become this circular arc. Such a valve body 20 is inserted into the bore 19, a first in-valve flow path 25 is formed from one groove and the bore 19, and a second in-valve flow path 26 is formed from the other groove and the bore 19. Will be composed. As described above, the valve body 20 can rotate in the bore 19, but can take two rotational positions, that is, first and second positions. The first to fourth connection flow paths 23a, 23b,... Are communicated with or blocked from each other by the first and second intra-valve flow paths 25, 26 depending on the first and second positions taken by the valve body 20. It is like that. Specifically, when the valve body 20 is switched to the first position, as shown in FIG. 1A, the first connection flow path 23a and the second connection flow path 23b. Are communicated by the first in-valve channel 25, and the third channel 23 c and the fourth channel 23 d are communicated by the second in-valve channel 26. Therefore, at this time, the plasticizing device 2 and the first injection device 4 and the second injection device 5 and the injection nozzle 8 communicate with each other. When the valve body 20 is switched to the second position, as shown in FIG. 1A, the first connection flow path 223a and the fourth connection flow path 23d are connected to the first position. The second connection flow path 23 b and the third connection flow path 23 c communicate with each other through the second valve flow path 26. Therefore, at this time, the plasticizing device 2 and the second injection device 5 and the first injection device 4 and the injection nozzle 8 communicate with each other.

  The plasticizing / injecting apparatus 1 according to the present embodiment alternately measures the first and second injecting apparatuses 4 and 5 while injecting the resin continuously in the plasticizing apparatus 2 and alternately from the injection nozzle 8. It can be injected. An operation method of the plasticizing injection apparatus 1 according to the present embodiment will be described.

  First, in the flow path switching device 7 according to the present embodiment, the flow path switching valve 21 is switched to the first position as shown in FIG. Then, the first and second connection flow paths 23 a and 23 b communicate with each other via the first intra-valve flow path 25. That is, the plasticizing device 2 and the first injection device 4 communicate with each other. A predetermined axial force is applied to the plunger 16 in advance. When the heating cylinder 10 is heated in the plasticizing device 2 and the screw 11 is rotated, the resin is melted and supplied from the plasticizing device 2 to the first injection device 4. The plunger 16 is retracted by the pressure of the molten resin. That is, it is weighed.

  Incidentally, in this state, a relatively high resin pressure is applied to the first in-valve channel 25. This is due to the axial force applied to the plunger 16 and the flow resistance of the resin flowing in the flow path. Accordingly, an eccentric load acts on the valve body 20 in the direction of the arrow Y1. If the valve body 20 is rotated in this state to switch the flow path switching valve 21, a large driving force is required, and the flow path switching valve 21 may be worn or damaged. Therefore, the pressure of the resin in the first in-valve channel 25 is reduced. Specifically, the plunger 16 is retracted by a predetermined length in the first injection device 4. The resin pressure drops and the eccentric load is eliminated.

  The flow path switching valve 21 is switched to the second position as shown in FIG. Since the eccentric load is not acting, the valve body 20 rotates smoothly in the bore 19. When switched, the first and fourth connection flow paths 23 a and 23 d communicate with each other via the first intra-valve flow path 25. That is, the plasticizing device 2 and the second injection device 5 communicate with each other. The plasticizer 2 is continuously operated to melt the resin. Then, the molten resin is supplied to the second injection device 5. On the other hand, in the second position, the second and third connection flow paths 23 b and 23 c also communicate with each other via the second intra-valve flow path 26. That is, the first injection device 4 and the injection nozzle 8 communicate with each other. In the first injection device 4, the plunger 16 is driven in the axial direction for injection, and a molten resin is filled in a mold not shown in the drawing, and pressure is maintained. When the resin filled in the mold is cooled and solidified, the mold is opened to take out the molded product, and the mold is clamped again. As described above, when the injection process and the pressure holding process are performed by the first injection device 5, the resin is supplied to the second injection device 5 from the plasticizing device 2 and measured.

  When the measurement is completed, a high resin pressure is applied in the flow path switching device 7, and an eccentric load is applied to the valve body 20 by this resin pressure. In the second injection device 5, the plunger 17 is moved backward to reduce the resin pressure in the flow path switching device 7. Further, the plunger 16 is also retracted in the first injection device 4 as necessary. This is because the resin pressure in the injection / holding process may remain. As a result, the eccentric load acting on the valve body 20 is eliminated. As shown in FIG. 1A, the flow path switching valve 21 is switched to the first position. The valve body 20 rotates smoothly in the bore 19. When switched, the plasticizing device 2 and the first injection device 4 communicate with each other, and metering is started in the first injection device 4 as described above. In other words, plasticization is not interrupted. In the first position, the second injection device 5 and the injection nozzle 8 communicate with each other. In the second injection device 5, the plunger 17 is driven in the axial direction for injection, a mold not shown in the drawing is filled with resin, and pressure is maintained.

  When the injection / holding process is completed in the second injection device 5 and the metering is completed in the first injection device 4, the plunger 16 of the first injection device 4 is moved backward so that the inside of the flow path switching device 7 Reduce resin pressure. The plunger 17 of the second injection device 4 is retracted as necessary. As a result, the eccentric load acting on the valve body 20 is eliminated. As described above, the flow path switching valve 21 is switched and the molding is repeated.

  In the operation method of the plasticizing injection apparatus 1 according to the present embodiment, the plungers 16 and 17 are moved backward when the pressure of the resin in the flow path switching device 7 is lowered when switching the flow path switching valve 21. . That is, the pressure of the resin is reduced by operating the plungers 16 and 17. On the other hand, the plasticizing / injecting apparatus 1 ′ according to the second embodiment to be described next is a pressure reducing means capable of reducing the pressure of the resin in the flow path switching device 7 without operating the plungers 16 and 17. It has. As shown in FIG. 2, the plasticizing injection apparatus 1 ′ according to the second embodiment is similar to the plasticizing injection apparatus 1 according to the previous embodiment, and the plasticizing injection apparatus 1 according to the previous embodiment. The same members as those in the chemical injection apparatus 1 are denoted by the same reference numerals and description thereof is omitted. The plasticizing injection apparatus 1 ′ according to the second embodiment is provided with first and second decompression apparatuses 27 and 28 in front of the first and second injection apparatuses 4 and 5, respectively. The first and second pressure reducing devices 27 and 28 include a bore communicating with the inside of the injection cylinders 13 and 14 from the side of the injection cylinders 13 and 14 and plungers 29 and 30 inserted into the bores. When the plungers 29 and 30 are retracted, the pressure of the resin in the first and second injection devices 4 and 5 is reduced, thereby reducing the pressure of the resin in the first and second in-valve channels 25 and 26. be able to. As can be easily understood by a person skilled in the art, the plasticizing injection device 1 according to the second embodiment can be operated without operating the plungers 16 and 17 of the first and second injection devices 4 and 5. It is possible to operate the flow path switching valve 21 by reducing the pressure of the resin in the flow path switching device 7 simply by operating the first and second pressure reducing devices 27 and 28.

  In the present embodiment, the plasticizing injection apparatus 1 is provided with two injection apparatuses, that is, the first and second injection apparatuses 4 and 5, so that they can be alternately injected. However, only one injection device may be attached to the flow path switching device 7 according to the present embodiment. FIG. 3 shows a plasticizing injection apparatus 1 ″ according to such a third embodiment. The plasticizing / injecting apparatus 1 '' according to this embodiment includes the plasticizing apparatus 2 and the first connecting flow paths 23a, 23b and 23c in the flow path switching apparatus 7 according to the present embodiment. 1 injection device 4 and injection nozzle 8 are connected. However, a discharge portion 45 that discharges the resin to the outside is connected to the fourth connection flow path 23d. Therefore, as shown in FIG. 3, when the flow path switching valve 21 takes the second position, the resin supplied from the plasticizing device 2 is discharged from the discharge portion 45 to the outside. . Since the resin is discharged, the resin is somewhat wasted, but the plasticizing device 2 can be operated continuously. Therefore, the flow path switching valve 21 is switched to the first position and the plasticizing device 2 to the first injection device 4 are switched. It is guaranteed that the quality of the resin is always supplied. Also in the plasticizing / injecting apparatus 1 '' according to the third embodiment, when switching the flow path switching valve 21, the plunger 16 is retracted in advance to reduce the pressure of the resin in the flow path switching apparatus 7. Be sure to do it later.

  FIG. 4 shows a flow path switching device 7 ″ according to another modified embodiment. In this flow path switching device 7 ″, the valve body 20 ′ is formed in a substantially rectangular parallelepiped shape, and is provided in the rectangular parallelepiped hole 31 opened in the flow path switching device 7 ″ so as to be smoothly slidable. Four grooves 32, 33, 34, and 35 are formed in the valve body 20 '. The groove 32 and the groove 33 are formed at the same height, and the groove 34 and the groove 35 are formed at the same height below them. The valve body 20 'is slid to switch between the first position where the grooves 32, 33 are aligned with the first to fourth connection flow paths 23a, 23b, ... and the second position where the grooves 34, 35 are aligned. If so, the flow path can be switched. As can be easily understood by those skilled in the art, even in such a flow path switching device 7 ″, an eccentric load acts on the valve body 20 ′ by the pressure of the resin. Therefore, before the valve body 20 'is slid, the pressure of the resin in the flow path switching device 7 "is reduced before the valve body 20' is slid.

In the plasticizing injection apparatus 1 according to the embodiment of the present invention, an experiment was conducted to confirm that the operation of the flow path switching valve 21 is facilitated by carrying out the operation method according to the present invention.
Experiment contents:
The plasticizing injection apparatus 1 according to the embodiment of the present invention was used. As shown in FIG. 1A, the plasticizer 1 is provided with a pressure sensor P at the tip of the heating cylinder 10, and the pressure of the resin in this portion is measured. As the resin, polyamide 6 containing 30% by weight of carbon fibers was used. In the flow path switching device 7, the flow path switching valve 21 was set to the first position, and the resin melted in the plasticizing device 2 was weighed to the first injection device 4. At this time, the discharge amount from the plasticizer 2 was set to 30 kg / hr, and the back pressure was applied to the plunger 16 so that the pressure of the resin was about 4 Pa during measurement. After the measurement was completed, a predetermined weak torque was applied to the valve body 20 in that state, and switching of the flow path switching valve 21 was attempted. That is, switching of the flow path switching valve 21 was attempted without reducing the pressure of the resin in the flow path switching device 7. However, the valve body 20 did not rotate. Next, the plunger 16 was retracted, and the pressure of the resin in the flow path switching device 7 was reduced. When the valve body 20 was rotated with the same torque in this state, the valve body 20 rotated smoothly and the flow path switching valve 21 was switched.
Discussion:
It was confirmed that when the resin pressure in the flow path switching device 7 was decreased, the valve body 20 could be rotated smoothly and the flow path switching valve 21 could be switched smoothly. Since the flow path switching valve 21 can be switched smoothly, it is expected that the flow path switching valve 21 is not easily worn even when the flow path switching valve 21 is repeatedly switched. It has been confirmed that the operation method of the plasticizing injection apparatus 1 according to the embodiment of the present invention is highly effective in protecting the flow path switching mechanism.

DESCRIPTION OF SYMBOLS 1 Plasticization injection apparatus 2 Plasticization apparatus 4 1st injection apparatus 5 2nd injection apparatus 7 Flow path switching apparatus 8 Injection nozzle 10 Heating cylinder 11 Screw 13, 14 Injection cylinder 16, 17 Plunger 19 Bore 20 Valve body 21 Flow Road switching valve
23a, 23b, 23c, 23d First to fourth connection flow channels 25 First valve flow channel 26 Second valve flow channel 28, 29 First and second pressure reducing devices

Claims (4)

A flow path switching device including first to fourth connection flow paths and one flow path switching valve; a plasticizing apparatus connected to the first connection flow path; and the second connection flow path. A plunger type injection device connected to the first connection flow path and an injection section connected to the third connection flow path, and the first connection flow path when the flow path switching valve is switched to the first position. And the second connection flow path and the third connection flow path and the fourth connection flow path communicate so that the resin melted in the plasticizing apparatus is measured by the injection apparatus When the flow path switching valve is switched to the second position, the first connection flow path and the fourth connection flow path communicate with each other, and the second connection flow path and the third connection flow flow. The resin is melted in the plasticizing device through the passage and flows into the fourth connection flow path, and the injection device In plasticizing injection device is a resin adapted to be emitted from the exit portion,
When the target resin is a resin containing carbon fiber, the pressure of the resin in the flow path switching device applied from the plasticizing device is reduced when the flow path switching valve is switched to the injection device after the completion of measurement. And a method for operating the plasticizing injection apparatus, wherein the switching is performed thereafter.   2. The method of operating a plasticizing injection apparatus according to claim 1, wherein the pressure of the resin in the flow path switching device is reduced by forcibly retreating a plunger provided in the injection device by a predetermined stroke. A method of operating a plasticizing injection apparatus, characterized in that   3. The method of operating a plasticizing injection apparatus according to claim 1 or 2, wherein the plasticizing injection apparatus includes another injection device connected to the fourth connection flow path, and the flow path switching valve is the first. When the position is switched to position 2, the resin melted in the plasticizing apparatus is metered to the other injection apparatus, and when the flow path switching valve is switched to the first position, the other injection apparatus. The resin from the injection section is injected from the injection section, and when the flow path switching valve is switched to the other injection apparatus after completion of metering, the flow path switching apparatus is applied from the plasticizing apparatus. A method of operating a plasticizing injection apparatus, wherein the pressure of the resin is reduced and then switched.   4. The method of operating a plasticizing injection device according to claim 3, wherein the pressure of the resin in the flow path switching device is reduced by forcing a plunger provided in the other injection device only to a predetermined stroke. A method of operating a plasticizing injection apparatus, wherein the plasticizing injection apparatus is performed by retreating.

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