JP2004017450A - Injection equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent nonuniformity in the density of a molding material to be filled in a cavity space. <P>SOLUTION: This equipment has a first cylinder member, an injection member, a second cylinder member connected to a prescribed position of the first cylinder member and a plasticizing member. A connecting member making the first and second cylinder members communicate with each other is opened, on the second cylinder member side, at a start position of metering set in the rear at a prescribed distance from an advance limit position of the injection member. In a metering process, the molding material in the second cylinder member is supplied to the vicinity of the start position of metering in the first cylinder member through the intermediary of the connecting member and moved forward from the start position through the first cylinder member. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an injection device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a pre-plastic injection apparatus includes a first heating cylinder and a second heating cylinder connected to a predetermined position at a front end of the first heating cylinder via a communication pipe. A plunger is disposed in the first heating cylinder so as to be able to move forward and backward, and a screw is rotatably disposed in the second heating cylinder. A hopper for supplying a resin as a molding material is attached to a rear end of the second heating cylinder.
[0003]
Then, during the weighing step, the screw is rotated in the second heating cylinder, the resin supplied from the hopper is melted, moved forward, and supplied into the first heating cylinder via the communication pipe. Is done. Along with this, the plunger placed at the forward limit position in the first heating cylinder is retracted by the pressure of the resin, and weighing is performed. Then, a predetermined amount of resin is stored in front of the plunger, and when the plunger reaches the measurement completion position, the rotation of the screw is stopped, and the measurement process is completed.
[0004]
Further, when the plunger is advanced in the first heating cylinder during the injection step, the resin is injected from the injection nozzle attached to the front end of the first heating cylinder, and the resin is charged into the cavity space of the mold apparatus. Is done. Then, when the plunger reaches the forward limit position, the injection process is completed.
[0005]
[Problems to be solved by the invention]
However, in the conventional injection device, during the measuring step, the resin in the second heating cylinder is supplied to the vicinity of the front end in the first heating cylinder through the communication pipe, and the resin in the first heating cylinder is supplied. Is moved from the front to the rear, so that during the injection step, the resin supplied last in the first heating cylinder is injected first from the injection nozzle, and is supplied first in the first heating cylinder. The injected resin will be injected from the injection nozzle most recently. That is, a last-in first-out injection is performed.
[0006]
Therefore, the resin supplied first into the first heating cylinder is moved a long distance, and the resin supplied last into the first heating cylinder is moved a short distance, so that the cavity space is filled. Variations occur in the flow history of the applied resin, and variations occur in the temperature distribution and pressure distribution of the resin. As a result, the density of the resin filled in the cavity space varies, and the quality of the molded product deteriorates.
[0007]
By the way, when the injection step is completed, the plunger is placed at the forward limit position in the first heating cylinder. At this time, the plunger is moved so that the front end of the plunger does not hit the inner peripheral surface of the injection nozzle. The forward limit position is set rearward by a predetermined distance (cushion amount) from a position corresponding to the inner peripheral surface of the nozzle. In this case, when the injection step is completed, the resin remains in the first heating cylinder between the opening of the communication pipe and the front end of the plunger, and the measurement step is started for the next shot. Then, as the plunger is retracted, the remaining resin is moved backward. Therefore, the remaining resin cannot be discharged out of the first heating cylinder, and is deteriorated and discolored or deteriorated, and the discolored or deteriorated resin is injected from the injection nozzle for some reason. In such a case, the quality of the molded product is deteriorated.
[0008]
The present invention solves the problems of the conventional injection device, and the density of the molding material filled in the cavity space varies, the color of the material is changed, or the deteriorated molding material is injected from the injection nozzle. It is an object of the present invention to provide an injection device capable of improving the quality of a molded product without performing the same.
[0009]
[Means for Solving the Problems]
For this purpose, in the injection device of the present invention, the first cylinder member, the injection member arranged to be able to advance and retreat within the first cylinder member, and the first cylinder member are connected to a predetermined position of the first cylinder member. A second cylinder member, and a plasticizing member rotatably disposed in the second cylinder member.
[0010]
The connecting member that communicates the first and second cylinder members is opened at the second cylinder member side at a measurement start position set a predetermined distance behind the forward limit position of the injection member. .
[0011]
In another injection device of the present invention, a valve member for applying a back pressure to the molding material in the second cylinder member is further provided in the connecting member.
[0012]
In still another injection device of the present invention, the injection device further includes a measurement processing unit that rotates the plasticizing member in a state where the injection member is located at the measurement start position.
[0013]
In still another injection device of the present invention, the weighing means places the injection member at a weighing completion position in accordance with the back pressure of the injection member when completing the weighing step.
[0014]
In still another injection device of the present invention, the weighing start position and the weighing completion position further match.
[0015]
In still another injection device of the present invention, the weighing completion position is further located behind the weighing start position.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a schematic diagram of an injection device according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a state when a measuring process of the injection device according to the embodiment of the present invention is started, and FIG. 3 is an embodiment of the present invention. And FIG. 4 is a diagram showing a state when the injection step of the injection device according to the embodiment of the present invention is completed.
[0018]
In the drawing, reference numeral 43 denotes an injection device, and the injection device 43 is disposed on an injection molding machine frame (not shown) together with a mold device (not shown) and a mold clamping device (not shown). The mold device is composed of a fixed mold and a movable mold, and the mold clamping device is a fixed platen fixed to the injection molding machine frame, a movable platen, a toggle mechanism, and a mold clamping apparatus for operating the toggle mechanism. A mold clamping motor is provided as a drive unit, and the movable platen is advanced and retracted by driving the mold clamping motor to operate a toggle mechanism, thereby performing mold closing, mold clamping and mold opening of the mold apparatus. When the mold is clamped, a cavity space is formed between the movable mold and the fixed mold.
[0019]
The injection device 43 includes a first heating cylinder 47 serving as a first cylinder member, and a plunger 21 serving as an injection member which is disposed in the first heating cylinder 47 so as to be able to advance and retreat (move in the left-right direction in the figure). An injection cylinder 49 serving as a metering / injection drive unit for moving the plunger 21 forward and backward, is connected to a predetermined portion of the first heating cylinder 47, and extends obliquely upward from the connection position to form a molding material. A second heating cylinder 51 serving as a second cylinder member that melts the resin and supplies the first heating cylinder 47 to the first heating cylinder 47, and a plasticizing member rotatably disposed in the second heating cylinder 51. , A hydraulic motor 59 as a plasticizing drive unit for rotating the screw 22, and a rear end of the second heating cylinder 51 (FIGS. 1 and 4). Mounted near the Oite rightmost), having a pelletized resin supply hopper 25 or the like in said second heating cylinder 51. The injection device 43 is moved forward / backward with respect to the fixed platen by an injection device moving mechanism (not shown), and can perform nozzle touch when moving forward (moving leftward in the figure).
[0020]
The first heating cylinder 47 includes a cylinder portion 46 and an injection nozzle 48 attached to a front end (a left end in the figure) of the cylinder portion 46, and a resin in the cylinder portion 46 is provided on an outer periphery of the cylinder portion 46. The heaters h1 and h2 are disposed as heating members for heating the resin and maintaining the molten state, and on the outer periphery of the injection nozzle 48, as a heating member for heating the resin in the injection nozzle 48 and maintaining the molten state. The heater h3 is provided, and energization is controlled by a control unit (not shown). A nozzle port 23 is formed at the front end of the injection nozzle 48.
[0021]
The second heating cylinder 51 includes a cylinder portion 57 and a communication pipe 58 as a connecting member that connects the front end of the cylinder portion 57 and the first heating cylinder 47. The heaters h4 to h6 are provided as heating members for heating and melting the resin supplied into the second heating cylinder 51, and the energization is controlled by the control unit. The communication pipe 58 is provided with a communication passage 31 for communicating the insides of the first and second heating cylinders 47 and 51, and the communication passage 31 has a valve member 32 having functions such as a switching valve and a control valve. Is arranged. The valve member 32 is opened and closed by driving a predetermined actuator (not shown) by the control unit, and selectively communicates and shuts off the communication passage 31 between the first and second heating cylinders 47 and 51. It is possible to control the flow rate of the passing resin by adjusting the opening degree.
[0022]
In the present embodiment, a ball valve is used as the valve member 32. However, a needle valve, a slide mechanism, or the like may be used instead of the ball valve.
[0023]
In the first heating cylinder 47, a first weighing setting for starting a weighing process, which is set at a forward limit position of the plunger 21 and a predetermined distance behind (to the right in the drawing) from the forward limit position. A weighing start position as a position is set, and the plunger 21 is moved forward and backward by driving the injection cylinder 49, and is placed at a forward limit position as shown in FIG. 4 or as shown in FIG. Or placed at the weighing start position.
[0024]
The communication passage 31 is opened at the measurement start position on the first heating cylinder 47 side, and is opened at the front end of the cylinder portion 57 on the second heating cylinder 51 side. The measurement start position is set at a predetermined distance behind the nozzle port 23 so as to secure the amount of resin required for measurement in the first heating cylinder 47.
[0025]
When the injection step is completed, the plunger 21 is placed at the forward limit position. At this time, the plunger 21 is moved to the injection nozzle 48 so that the front end of the plunger 21 does not hit the inner peripheral surface of the injection nozzle 48. The forward limit position is set rearward by a predetermined distance from a position corresponding to the inner peripheral surface of the vehicle.
[0026]
The screw 22 includes a screw body 26 and a flight 27 formed in a spiral shape on the outer circumference of the screw body 26, and a spiral groove 28 is formed along the flight 27. Also, the screw 22 has a supply unit to which the resin dropped from the hopper 25 is supplied in order from the rear to the front (left side in FIGS. 1 and 4), a compression unit to compress the supplied resin and melt it, and A measuring section for measuring a fixed amount of the melted resin is formed. The outer diameter of the screw body 26 is made relatively small in the supply section, gradually increased from the rear to the front in the compression section, and made relatively large in the metering section. Therefore, the gap (gap) between the inner peripheral surface of the second heating cylinder 51 and the outer peripheral surface of the screw main body 26 is relatively large in the supply unit, and is gradually reduced from the rear to the front in the compression unit, It is relatively small in the metering section.
[0027]
In the present embodiment, the injection cylinder 49 is used as the injection drive unit, and the hydraulic motor 59 is used as the plasticization drive unit, but instead of the injection cylinder 49, the hydraulic motor 59, etc. Thus, an electric motor such as a servomotor can be used. 1 and 4, reference numeral 61 denotes a coupler for connecting the plunger 21 and the output shaft of the injection cylinder 49, and reference numeral 62 denotes a coupler for connecting the screw 22 and the output shaft of the hydraulic motor 59.
[0028]
In the injection device having the above-described configuration, before the weighing process is started, the plunger 21 is placed at the weighing start position as shown in FIG. 2, and the control unit drives the actuator to move the inside of the communication passage 31. A predetermined opening degree is set in the valve member 32 so that a predetermined amount of resin flows. Then, when the weighing process is started, the weighing means (not shown) of the control unit performs the weighing process, drives the hydraulic motor 59 with the plunger 21 at the weighing start position, and rotates the screw 22. Along with that, the resin in the hopper 25 is supplied into the second heating cylinder 51 and further supplied to the supply unit. The resin supplied to the supply unit advances in the groove 28 with the rotation of the screw 22, enters a semi-molten state in the compression unit, is completely melted in the measuring unit, becomes liquid, and passes through the communication passage 31. As shown by an arrow in FIG. 2, the liquid is supplied to the first heating cylinder 47, flows in the first heating cylinder 47 forward from the measurement start position, and is stored forward of the plunger 21.
[0029]
During this time, in the second heating cylinder 51, the resin tends to move forward with the rotation of the screw 22, but the flow rate of the resin in the communication passage 31 is restricted by the valve member 32, Squeezed. That is, since a back pressure according to the opening degree can be applied to the resin in the second heating cylinder 51, the density of the plasticized resin can be made uniform. As a result, the quality of the molded product can be improved.
[0030]
By the way, a pressure sensor as a pressure detecting unit (not shown) is provided at a predetermined position behind the plunger 21, detects the pressure of the resin in the first heating cylinder 47, and sends a detection signal to the control unit. It is supposed to be sent. When a sufficient amount of resin is stored in front of the plunger 21 and the pressure detected by the pressure sensor becomes equal to or greater than a threshold value, the control unit drives the actuator, as shown in FIG. Then, the valve member 32 is closed to shut off the communication passage 31, and the drive of the hydraulic motor 59 is stopped to stop the rotation of the screw 22. Even if the pressure detected by the pressure sensor becomes equal to or higher than the threshold value and the valve member 32 is closed and the communication pipe 31 is shut off, the pressure in front of the plunger 21 is not necessarily maintained at the threshold value, and thereafter. May keep getting higher.
[0031]
Therefore, when the pressure detected by the pressure sensor is maintained at the threshold value, the weighing completion position and the weighing start position are matched, and the weighing completion position is directly set as the weighing start position. On the other hand, when the pressure detected by the pressure sensor is not held at the threshold value and continues to increase thereafter, and the pressure higher than the threshold value acts on the plunger 21, the measurement processing unit drives the injection cylinder 49, The plunger 21 is moved backward (moved rightward in the figure) in the direction of the arrow in FIG. 3 so that the pressure detected by the pressure sensor is maintained at a threshold value. In this case, the weighing completion position is located behind the weighing start position. Then, when the pressure detected by the pressure sensor at the measurement completion position becomes a threshold value, the measurement processing means completes the measurement process.
[0032]
When the pressure in front of the plunger 21 is high and the speed of the resin supplied into the first heating cylinder 47 is high, the measurement completion position is located sufficiently behind the measurement start position.
[0033]
In this case, when the pressure detected by the pressure sensor becomes equal to or higher than the threshold value, the plunger 21 is retracted by a predetermined distance from the measurement start position to the measurement completion position, so that the measurement can be reliably performed.
[0034]
Subsequently, the control unit drives the actuator to close the valve member 32 and maintain a state in which the first and second heating cylinders 47 and 51 are shut off, as shown in FIG. Then, an injection processing unit (not shown) of the control unit performs an injection process, drives the injection cylinder 49, and advances the plunger 21 toward the forward limit position as indicated by an arrow in FIG. Along with this, the resin stored in front of the plunger 21 is injected by the injection nozzle 48 and filled in the cavity space.
[0035]
When the plunger 21 reaches the forward limit position, the injection processing means stops driving the injection cylinder 49, stops the plunger 21, and completes the injection process. Then, the weighing processing means drives the injection cylinder 49 to retreat the plunger 21 for the next shot and place the plunger 21 at the weighing start position.
[0036]
As described above, at the time of the measuring step, the resin in the second heating cylinder 51 is supplied to the vicinity of the measuring start position of the plunger 21 in the first heating cylinder 47 via the communication path 31 and the first heating is performed. Since the inside of the cylinder 47 is moved forward from the measurement start position, at the time of the injection process, the resin supplied into the first heating cylinder 47 is injected first from the injection nozzle 48 first, and the The resin supplied into one heating cylinder 47 is injected from the injection nozzle 48 most recently. That is, a first-in first-out injection is performed.
[0037]
Therefore, the resin supplied first into the first heating cylinder 47 and the resin supplied last into the first heating cylinder 47 are moved by the same distance, so that the resin filled in the cavity space is filled. Not only does not cause a variation in the flow history, but also does not vary in the temperature distribution and the pressure distribution of the resin. As a result, it is possible to prevent the density of the resin filled in the cavity space from being varied, thereby improving the quality of the molded product.
[0038]
When the injection step is completed, the forward end position is set so that the front end of the plunger 21 does not contact the inner peripheral surface of the injection nozzle 48. In the vicinity of the front end. However, since the remaining position is ahead of the opening of the communication passage 31, even if the measuring process is started for the next shot, the remaining resin does not move backward with the retreat of the plunger 21. Therefore, the remaining resin can be reliably discharged to the outside of the first heating cylinder 47 in the next shot, so that the resin is not deteriorated to be discolored or deteriorated. As a result, the quality of the molded product can be improved.
[0039]
It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.
[0040]
【The invention's effect】
As described above in detail, according to the present invention, in the injection device, the first cylinder member, the injection member disposed to be able to advance and retreat in the first cylinder member, and the first cylinder A second cylinder member connected to a predetermined position of the member; and a plasticizing member rotatably disposed within the second cylinder member.
[0041]
The connecting member that communicates the first and second cylinder members is opened at the second cylinder member side at a measurement start position set a predetermined distance behind the forward limit position of the injection member. .
[0042]
In this case, the connecting member that allows the first and second cylinder members to communicate with each other is opened at the second cylinder member side at a measurement start position that is set a predetermined distance behind the forward limit position of the injection member. Therefore, at the time of the measuring step, the molding material in the second cylinder member is supplied to the vicinity of the measurement start position of the injection member in the first cylinder member via the connecting member, and the inside of the first cylinder member is measured. It is moved forward from the start position. Therefore, at the time of the injection step, the molding material supplied first into the first cylinder member is injected first from the injection nozzle, and the molding material supplied last into the first cylinder member is injected last from the injection nozzle. It will be ejected from. That is, a first-in first-out injection is performed.
[0043]
As a result, the molding material supplied first into the first cylinder member and the molding material supplied last into the first cylinder member are moved by the same distance, so that the cavity space is filled. Not only does the flow history of the molding material vary, but also the temperature distribution and the pressure distribution of the molding material do not vary. In addition, since it is possible to prevent the density of the molding material filled in the cavity space from being varied, it is possible to improve the quality of the molded product.
[0044]
When the injection step is completed, the forward end position is set so that the front end of the injection member does not hit the inner peripheral surface of the injection nozzle. And remains in the vicinity of the front end of the injection member. However, since the remaining position is in front of the opening of the connecting member, even if the measuring step is started for the next shot, the remaining molding material does not move backward with the retreat of the injection member. Therefore, the remaining molding material can be reliably discharged to the outside of the first cylinder member in the next shot, so that the molding material is not deteriorated and discolored or deteriorated. As a result, the quality of the molded product can be improved.
[0045]
In another injection device of the present invention, a valve member for applying a back pressure to the molding material in the second cylinder member is further provided in the connecting member.
[0046]
In this case, since a back pressure can be applied to the molding material in the second cylinder member, the density of the plasticizing molding material can be made uniform. As a result, the quality of the molded product can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic view of an injection device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a state when a measuring step of the injection device according to the embodiment of the present invention is started.
FIG. 3 is a diagram illustrating a state when a measuring step of the injection device according to the embodiment of the present invention is completed.
FIG. 4 is a diagram showing a state when the injection process of the injection device according to the embodiment of the present invention is completed.
[Explanation of symbols]
21 Plunger 22 Screw 32 Valve member 43 Injection device 47, 51 First and second heating cylinder 58 Communication pipe

Claims (6)

(A) a first cylinder member;
(B) an injection member disposed to be able to advance and retreat within the first cylinder member;
(C) a second cylinder member connected to a predetermined position of the first cylinder member;
(D) a plasticizing member rotatably disposed in the second cylinder member;
(E) The connecting member for communicating the first and second cylinder members is opened at the metering start position set a predetermined distance behind the forward limit position of the injection member on the second cylinder member side. An injection device, characterized in that it can be used. The injection device according to claim 1, wherein a valve member for applying a back pressure to the molding material in the second cylinder member is provided in the connection member. The injection device according to claim 1, further comprising a measurement processing unit configured to rotate the plasticizing member in a state where the injection member is located at a measurement start position. The injection device according to any one of claims 1 to 3, wherein the measurement processing unit places the injection member at a measurement completion position in accordance with a back pressure of the injection member when completing the measurement process. The injection device according to claim 4, wherein the measurement start position and the measurement completion position match. The injection device according to claim 4, wherein the measurement completion position is located behind the measurement start position.

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