JP4801652B2 - Material supply equipment for injection molding machines - Google Patents

Description

  The present invention relates to a material supply apparatus for an injection molding machine capable of performing quantitative cutting.

  An injection molding machine having a hopper in a heating cylinder and supplying a molding material stored in the hopper to the heating cylinder is widely used in practical use. In this type of injection molding machine, the mass of the molding material per injection cannot be strictly controlled.

However, depending on the type of the molded product, it is necessary to strictly control the mass of the molding material per injection. A quantitative supply device that can meet this demand has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 7-60794 (FIG. 4)

Patent document 1 is demonstrated based on the following figure.
FIG. 14 is a diagram for explaining a basic configuration of a conventional technique, and a fixed amount supply device 105 is disposed between a heating cylinder 102 that rotatably houses a screw 101 and a hopper 103. The fixed amount supply device 105 includes a horizontal cylinder 106, a cutting screw 107 that is rotatably accommodated in the cylinder 106, and a motor 108 that rotates the cutting screw 107.

  When the cutting screw 107 is turned, the molding material 111 in the hopper 103 is guided into the cylinder 106 through the introduction passage 112. The molding material 111 is moved to the left in the drawing by the action of the spiral blade 113 of the cutting screw 107 and falls into the heating cylinder 102 from the discharge passage 114. When the cutting screw 107 is stopped, the movement of the molding material 111 is also stopped. Since the moving amount (cutting amount) is uniquely determined from the pitch of the spiral blade 113 and the rotational speed of the cutting screw 107, quantitative cutting can be performed.

As described above, the quantitative supply device 105 having the cutting screw 107 as a main element is widely adopted because of its simple structure and operation.
However, the spiral blade 113 has a low cutoff performance, and the molding material 111 falls from the vicinity of the blade 115 at the back of the drawing, for example, indicated by a broken line. As a result, the supply amount varies.
Further, since the cylinder 106 is a stationary body and the swirl vane 113 is a rotating body, a part of the molding material 111 is sandwiched between the cylinder 106 and the swirl vane 113, and a large resistance is applied to the motor 108. Therefore, it is necessary to employ a large and high output motor.

  That is, the conventional quantitative supply device 105 having the main cutting screw 107 as a main element is difficult to cut with high accuracy, and it is difficult to reduce the size of the motor.

  An object of the present invention is to provide a material supply apparatus that can reduce the size of a driving means such as a motor and can perform cutting with high accuracy.

The invention according to claim 1 is an injection molding machine that quantitatively supplies the molding material by interposing it between a hopper that supplies the molding material and a heating cylinder that receives the molding material and plasticizes, measures, and injects it. In the material supply apparatus of
The material supply device is connected to an introduction passage for receiving the molding material supplied to the hopper, a discharge passage for discharging the molding material to the heating cylinder, an outlet of the introduction passage, and an inlet of the discharge passage. An intermediate passage, a piston movably accommodated in the intermediate passage so as to close the outlet of the introduction passage, and a notch formed at the front end of the piston for accommodating a molding material, and a front end is opened. Driving means for reciprocating the piston so that the groove portion and the position where the groove portion can face from the outlet of the introduction passage are defined as a backward limit position, and the position where the groove portion cannot face the outlet of the introduction passage is defined as a forward limit position The groove portion is characterized in that the depth of the groove increases toward the tip and the width of the groove increases toward the tip .

  The invention according to claim 2 is characterized in that the intermediate passage is an inclined passage that descends toward the discharge passage.

Inventions is according to claim 3, a hopper for supplying the molding material, plasticized, weighed receiving the molding material, is interposed between the heating cylinder to perform injection, injection molding quantitative supplying the molding material In the machine material supply device,
The material supply device is connected to an introduction passage for receiving the molding material supplied to the hopper, a discharge passage for discharging the molding material to the heating cylinder, an outlet of the introduction passage, and an inlet of the discharge passage. An intermediate passage, a piston movably accommodated in the intermediate passage so as to close the outlet of the introduction passage, and a notch formed at the front end of the piston for accommodating a molding material, and a front end is opened. Driving means for reciprocating the piston so that the groove portion and the position where the groove portion can face from the outlet of the introduction passage are defined as a backward limit position, and the position where the groove portion cannot face the outlet of the introduction passage is defined as a forward limit position And
The groove portion is composed of a plurality of groove portions having different capacities, and is configured such that one of the plurality of groove portions can face the outlet of the introduction passage by turning the piston .

The invention according to claim 4 is characterized in that the intermediate passage is an inclined passage that descends toward the discharge passage .

In the invention according to claim 5 , the groove portion is characterized in that the depth of the groove increases toward the tip and the width of the groove increases toward the tip .

In the invention according to claim 1, the groove portion scoops the molding material at the outlet of the introduction passage and discharges the scraped molding material through the discharge passage. Since the amount of cutting is determined from the product of the capacity of the groove and the number of reciprocations of the piston, high-precision cutting can be performed.
In addition, in the groove portion, the depth of the groove increases toward the tip, and the width of the groove increases toward the tip. That is, the base of the groove has a shape like the tip of a spoon. Considering the situation when the base of the groove portion having such a shape moves from the outlet of the introduction passage to the outside of the introduction passage, only a small amount of molding material is stored in the base of the groove portion. The resistance force generated by the pinch is hardly increased. As a result, the drive means can employ a small drive source with a small output.

  In the invention according to claim 2, the intermediate passage is an inclined passage that descends toward the discharge passage. Since the piston is inclined following the inclined passage, the molding material accumulated in the groove portion can be easily discharged to the discharge passage, and there is no fear that the molding material remains in the groove portion.

In the invention according to claim 3, the groove portion scoops the molding material at the outlet of the introduction passage and discharges the scooped molding material through the discharge passage. Since the amount of cutting is determined from the product of the capacity of the groove and the number of reciprocations of the piston, high-precision cutting can be performed.
In addition, grooves having different capacities can be selected, the specifications of the material supply device can be easily changed, and usability can be improved.

In the invention according to claim 4 , the intermediate passage is an inclined passage that descends toward the discharge passage. Since the piston is inclined following the inclined passage, the molding material accumulated in the groove portion can be easily discharged to the discharge passage, and there is no fear that the molding material remains in the groove portion.

In the invention according to claim 5 , in the groove portion, the depth of the groove increases toward the tip, and the width of the groove increases toward the tip. That is, the base of the groove has a shape like the tip of a spoon. Considering the situation when the base of the groove portion having such a shape moves from the outlet of the introduction passage to the outside of the introduction passage, only a small amount of molding material is stored in the base of the groove portion. The resistance force generated by the pinch is hardly increased. As a result, the drive means can employ a small drive source with a small output.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a side view of an injection molding machine equipped with a material supply apparatus according to the present invention. The injection molding machine 10 supports a heating cylinder 12 in which a screw 11 is rotatably and movably accommodated, and the heating cylinder 12. A cylinder support 13, an injection plate 14 directly connected to the screw 11, a ball nut 15 provided on the injection plate 14, a ball screw 16 screwed into the ball nut 15, and an injection motor 17 that rotates the ball screw 16 And a material supply device 20 on the tube support base 13, and a hopper 21 is provided on the material supply device 20.

  FIG. 2 is a cross-sectional view of the material supply device according to the present invention. The material supply device 20 includes an introduction passage 22 that receives the molding material falling from the hopper 21, a discharge passage 23 that discharges the molding material to the heating cylinder 12, An intermediate passage 26 connected to the outlet 24 of the introduction passage 22 and the inlet 25 of the discharge passage 23, a piston 27 movably accommodated in the intermediate passage 26 so as to close the outlet 24 of the introduction passage 22, and molding A groove 28 that is notched at the front end of the piston 27 to store the material and has a front end open, and a front end of the piston 27 when the groove 28 can be seen (viewed) from the outlet 24 of the introduction passage 22 The position P1 is set as the backward limit position, and the tip position P2 of the piston 27 when the groove 28 cannot face (view) from the outlet 24 of the introduction passage 22 is set as the forward limit position. Drive means 29 for reciprocating the piston 27 so that, the drive means 29 the piston 27, characterized in that it comprises a control unit 31 which controls for example to 10 reciprocating in one second.

  Reference numeral 32 denotes a number counter. The control unit 31 stops the driving unit 29 when the number of reciprocations reaches a predetermined number. The drive means 29 is preferably an air cylinder, but any type can be used as long as it is an actuator capable of linear drive such as a hydraulic cylinder or an electric cylinder.

  Preferably, the introduction passage 22, the intermediate passage 26 and the discharge passage 23 are formed in one square block 33. In the case of the corner block 33, the hopper 21 can be directly placed on the flat upper surface 34 and fastened with bolts 35 and 35. The flat lower surface 36 can be directly placed on the cylinder support 13, and the assembly of the material supply device 20 to the heating cylinder 12 and the assembly of the hopper 21 to the material supply device 20 are extremely easy.

  FIG. 3 is a perspective view of the piston, and the piston 27 is a cylinder having a semicircular cross-sectional groove 28 at the tip. The upper surface and the front end of the groove 28 are open. Preferably, the groove 28 has a spoon shape in which the groove depth D increases toward the tip 27a of the piston 27 and the width W of the groove increases toward the tip 27a.

The operation of the material supply apparatus 20 having the above configuration will be described next.
4A and 4B are diagrams for explaining the operation when the piston at the retreat limit position is advanced halfway, FIG. 4B is a cross-sectional view when the piston is at the retreat limit position, and FIG. 4A is a plan view of the main part of FIG. (D) is sectional drawing when a piston exists in the middle, (c) is a principal part top view of (d).

As shown in (b), the molding material 38 accumulated in the introduction passage 22 is prevented from dropping by the piston 27. However, as shown to (a), the molding material 39 (The code | symbol was changed for convenience.) Has accumulated in the groove part 28. FIG.
When the piston 27 is moved to the left in the figure at a high speed, the piston 27 moves forward as shown in FIG. At this moment, as shown in (c), there is one (or several) molding material 41 (the sign is changed for convenience) at the base of the groove 28. If the particle size of the molding material 41 is large, it remains in the introduction passage 22, and if the particle size is small, it moves to the left in the figure while being accommodated in the groove portion 28.

In order to clarify the effectiveness of the groove 28, a comparative example of the following figure will be described.
FIG. 5 is a diagram for explaining the operation of the grooveless piston. Like FIG. 4, (b) is a sectional view when the piston is in the retreat limit position, (a) is a plan view of the main part of (b), (d) ) Is a cross-sectional view when the piston is in the middle, and FIG.

In the retreat limit position, as shown in (a), a half-moon or crescent-shaped gap 121 is opened at the tip of the piston 120. Then, as shown in (b), the molding material 122 falls directly into the intermediate passage 123. A considerable portion of the dropped molding material 122 does not stay in the intermediate passage 123 but falls into the discharge passage 124. Since the drop amount fluctuates, the cutout amount is not stable.
Further, in (c) in which the piston 120 is advanced, a large number of molding materials 126 are interposed between the tip of the piston 120 and the edge of the introduction passage 125. Since these many molding materials 126 become resistance, it is necessary to push the piston 120 strongly.

4 (a) and 4 (b), since the molding material 39 is stored in the spoon-shaped groove 28, there is no concern that the molding material 39 will drop directly into the discharge passage 23. Does not adversely affect accuracy.
Further, as shown in FIG. 4C, since only one molding material 41 is interposed between the tip of the piston 27 and the edge of the inlet 24 of the introduction passage, the forward resistance of the piston 27 is increased. There is no.

The operation following FIG. 4 will be described with reference to FIG.
FIG. 6 is an operation explanatory diagram when the piston is advanced to the forward limit position and when the piston is retracted from the forward limit position to the reverse limit position.
As shown in (a), at the forward limit position, the piston 27 closes the introduction passage 22 with the body portion 27b. The groove 28 at the tip stores the molding material 39 like a spoon.
Next, the piston 27 at the forward limit position is retracted at a high speed. Then, as shown in (b), the molding material 39 leaves the groove 28 and falls through the discharge passage 23.

When the piston 27 is disposed at an angle θ, the cutting becomes smooth, and particularly when the piston 27 is retracted at a high speed, the molding material 39 is well separated from the groove 28. The angle θ is preferably in the range of 10 ° to 30 °. If it exceeds 30 °, the risk of the molding material 38 falling at the stage of FIG.
However, when the accuracy of the cutout amount is not so required, or when the retraction speed of the piston 27 is increased, the angle θ may be set to 0, that is, the piston 27 may be disposed horizontally.

Next, a more preferable form of the piston will be described.
FIG. 7 is a perspective view for explaining a more preferable form of the piston. If the piston 27 is a cylinder, three groove portions 28 can be cut out at a pitch of 120 °. It is also possible to form two pieces at a 180 ° pitch and four pieces at a 90 ° pitch.

And since the capacity | capacitance (the amount of storage of a molding material) can be changed by changing the depth and width of a groove | channel, since the groove part 28 can change three groove parts 28, 28B, and 28C (B and C are capacity | capacitances). Can be made to have different capacities.
For example, two bolt holes 44, 44 are provided in the flange 43 of the driving means 29, and six screw holes 45-50 are provided at a 60 ° pitch on the square block 33 side.

  If the bolts 51 and 51 are screwed into the screw holes 45 and 48, the groove portion 28 can face the introduction passage 22, and if the bolts 51 and 51 are screwed into the screw holes 46 and 49, the groove portion 28B becomes the introduction passage 22. If the bolts 51 and 51 are screwed into the screw holes 47 and 50, the groove portion 28 </ b> C can face the introduction passage 22.

  With the above structure, the grooves 28, 28B, and 28C having different capacities can be selected, the specifications of the material supply device can be easily changed, and usability can be improved.

Next, an example of a method for handling the material supply apparatus 20 according to the present invention will be described.
FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 2, and a material supply device 20 and a hopper indicated by imaginary lines are provided by extending a rail 52 horizontally from the tube support base 13 and providing a stopper 53 at the tip of the rail 52. 21 can be pulled out to the position indicated by the solid line. A mass meter 55 including a bucket 54 is provided below the discharge passage 23 of the material supply device 20 indicated by a solid line.

  The molding material 38 is put into the hopper 21 and the piston 27 is reciprocated a predetermined number of times. Since it can be reciprocated 10 times per second, if the fixed number is 1000 times, the piston 27 is reciprocated only for 100 seconds. Then, a certain amount of the molding material 38 accumulates in the bucket 54. If the accumulated amount is Q1, and the number of reciprocations is N1, the amount of cut-out per reciprocation of the piston 27 can be obtained by the formula (Q1 / N1).

  Next, the material supply device 20 and the hopper 21 are returned to the positions indicated by the solid lines, and the normal operation is performed. Since the cut-out amount per reciprocation is (Q1 / N1), the reciprocation number of the piston necessary for one injection amount in the normal operation is calculated, and the piston 27 is reciprocated by this reciprocation number.

In general, it is conceivable to mathematically calculate the capacity (volume, volume) of the groove 28 and determine the number of reciprocations of the piston 27 based on this capacity. However, an error is likely to occur due to the influence of the size of the molding material 38, the variation of the particle size, the humidity in the atmosphere, and the like.
In this regard, according to FIG. 8, in order to obtain the cutting amount (Q1 / N1) per reciprocation with the actual product, this (Q1 / N1) includes the size of the molding material 38, the variation in the particle size, All the influences such as humidity in the atmosphere are taken into consideration, and the accuracy of the cutting amount is dramatically increased.

  If the rail 52 is in the way or it is troublesome to pull out the material supply device 20, the discharge passage 23 of the material supply device 20 is a "G" -shaped passage composed of a straight passage and a branch passage, When a three-way switching valve is arranged at a branch point and (Q1 / N1) is measured, a branch passage may be used, and a normal passage may be used in normal operation.

Next, another embodiment of the material supply apparatus will be described.
FIG. 9 is a diagram of another embodiment of FIG. 2, and the same elements as those in FIG.
The material supply device 60 is integrally formed obliquely with the upper cylinder 62 connected to the lower end of the hopper 21 with a bolt 35 and having a circular cross-section upper material passage 61 provided vertically and the lower end of the upper cylinder 62. The first inclined flange 63, the upper guide plate 64 applied to the first inclined flange 63 from below, and the lower guide plate having the pocket 66 for receiving the shutter 65 and applied to the upper guide plate 64 from below. 67, a shutter 65 sandwiched between the upper guide plate 64 and the lower guide plate 67 and movably accommodated in the pocket 66, drive means 29 for reciprocating the shutter 65, and a control unit for controlling the drive means 29 31, a count counter 32 connected to the control unit 31 for counting the number of reciprocations of the shutter 65, and a lower member having a circular cross section connected by a bolt 35 on the cylinder support 13. A lower cylindrical body 72 in which a passage 69 is provided vertically and a second inclined flange 71 is integrally formed at the upper end, and the first inclined flange 63, the upper guide plate 64, the lower guide plate 67, and the second inclined flange 71 are shared. It consists of a long bolt 73 to be tightened.

  A material passage 74 for guiding the resin material dropped from the hopper 21 to the heating cylinder 12 is opened in the upper material passage 61, the through hole 75 opened in the upper guide plate 64, the pocket 66, and the lower guide plate 67. The lower hole 76 and the lower material passage 69 are formed. As shown in the drawing, the material passage 74 is a substantially straight passage, which is different from FIG. On the other hand, the point that the shutter 65 is reciprocated at high speed by the driving means 29 is the same as that in FIG.

FIG. 10 is a view taken in the direction of the arrow 10-10 in FIG. 9. The upper guide plate 64 is provided with a through hole 75 and a structure in which the through hole 75 is closed by the shutter 65 is adopted.
11 is a cross-sectional view taken along the line 11-11 in FIG. 10. The shutter 65 is in sliding contact with the lower surface of the upper guide plate 64, and the edge of the through hole 75 is provided with a slope 77. FIG.

  Returning to FIG. 10, the through hole 75 is elliptical on the upper surface (front surface in the figure) of the upper guide plate 64, but by providing slopes 77, 77, a semi-ellipse 78 is formed on the lower surface (the back surface in the figure). (A semi-ellipse divided by the minor axis) and the isosceles triangle 79 are combined to form a composite figure. Specifically, the composite figure is arranged so that the base 81 of the isosceles triangle 79 overlaps the chord of the semi-ellipse 78 and the apex angle 82 of the isosceles triangle 79 is located at the front portion 83 of the shutter 65.

Next, the operation of another embodiment described above will be described.
FIG. 12 is an explanatory view until the fully closed shutter moves to the middle open position. As shown in FIG. 12A, when the shutter 65 is in the fully closed position, the molding material 38 remains in the through hole 75. .
Next, as shown in (b), when the shutter 65 is opened as shown by the arrow (1), a small triangular passage 84 including the apex angle 82 is formed, and from the front to the back of the drawing via the small triangular passage 84. A part of the molding material 38 falls.

  FIG. 13 is an explanatory diagram when the fully opened shutter is closed. As shown in FIG. 13A, when the shutter 65 moves to the fully opened position as shown by the arrow (2), a large triangular passage 85 is formed. The molding material 38 actively falls from the front side of the drawing to the back side through the large triangular passage 85.

Next, as shown in (b), when the shutter 65 is closed as indicated by the arrow (3), one (or several) molding material 41 (for convenience sake, a symbol is provided in the valley formed by the apex angle 82). Changed.) Exists. If the particle size of the molding material 41 is large, it remains in the through hole 75, and if the particle size is small, it falls.
12 (a) → FIG. 12 (b) → FIG. 13 (a) → FIG. 13 (b) is repeated within a short time. By counting the number of reciprocations of the shutter 65, the cutout amount can be determined.

  Since the shutter 65 has a simple structure as compared with the piston 27 (FIG. 2), it is possible to easily achieve cost reduction of the material supply device.

As shown in FIG. 5C, a large number of molding materials 126 are interposed between the tip of the piston 120 and the edge of the introduction passage 125. Since these many molding materials 126 become resistance, it is necessary to push the piston 120 strongly.
In this regard, in FIG. 13B, there is no such concern, and the burden on the driving means 29 shown in FIG. 9 is reduced.
In addition, as shown in FIG. 13B, even when the molding material 41 is sandwiched and remains in the through hole 75, there is no fear that the molding material falls from the gap, so that high-precision cutting can be performed.

In FIG. 9, the shutter 65 is inclined with respect to the horizontal, but the shutter 65 may be horizontal. If the shutter 65 is horizontal, the through-hole 75 shown in FIG. 10 is a circle on the upper surface of the upper guide plate 64 and a composite figure in which an isosceles triangle is combined with a semicircle on the lower surface.
Therefore, the through hole 75 may be either a circular cross section or an elliptic cross section.

  The present invention is suitable for injection molding in which a fixed amount of material needs to be supplied to a heating cylinder.

It is a side view of the injection molding machine provided with the material supply apparatus which concerns on this invention. It is sectional drawing of the material supply apparatus which concerns on this invention. It is a perspective view of a piston. It is action | operation explanatory drawing when a piston in a retreat limit position is advanced halfway. It is operation | movement explanatory drawing by a piston without a groove | channel. It is operation | movement explanatory drawing when making a piston advance to an advance limit position, and making it retract from an advance limit position to a retreat limit position. It is a perspective view explaining the form of a more preferable piston. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 2. It is another Example figure of FIG. FIG. 10 is a view taken in the direction of arrow 10-10 in FIG. It is the 11-11 line sectional view of FIG. It is explanatory drawing until a fully closed shutter moves to a middle open position. It is explanatory drawing when closing a fully open shutter. It is a figure explaining the basic composition of the conventional technology.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Injection molding machine, 12 ... Heating cylinder, 20, 60 ... Material supply apparatus, 21 ... Hopper, 22 ... Introduction passage, 23 ... Discharge passage, 24 ... Outlet of introduction passage, 25 ... Inlet of discharge passage, 26 ... Middle Passage 27, piston, 27a ... tip of piston 28, 28B, 28C ... groove, 29 ... driving means, 38 ... molding material, P1 ... piston retract limit position, P2 ... piston forward position, D ... groove Depth, W ... width of groove, 64 ... upper guide plate, 65 ... shutter, 74 ... material passage, 75 ... through hole, 77 ... slope, 78 ... semi-ellipse, 79 ... isosceles triangle, 81 ... bottom.

Claims (5)

In a material supply device of an injection molding machine that quantitatively supplies the molding material by interposing between a hopper that supplies the molding material and a heating cylinder that receives the molding material, plasticizes, measures, and injects,
The material supply device is connected to an introduction passage for receiving the molding material supplied to the hopper, a discharge passage for discharging the molding material to the heating cylinder, an outlet of the introduction passage, and an inlet of the discharge passage. An intermediate passage, a piston movably accommodated in the intermediate passage so as to close the outlet of the introduction passage, and a notch formed at the front end of the piston for accommodating a molding material, and a front end is opened. Driving means for reciprocating the piston so that the groove portion and the position where the groove portion can face from the outlet of the introduction passage are defined as a backward limit position, and the position where the groove portion cannot face the outlet of the introduction passage is defined as a forward limit position It equipped with a door,
The groove portion has a groove depth that increases toward the tip and a groove width that increases toward the tip .   2. The material supply apparatus for an injection molding machine according to claim 1, wherein the intermediate passage is an inclined passage that descends toward the discharge passage. In a material supply device of an injection molding machine that quantitatively supplies the molding material by interposing between a hopper that supplies the molding material and a heating cylinder that receives the molding material, plasticizes, measures, and injects,
The material supply device is connected to an introduction passage for receiving the molding material supplied to the hopper, a discharge passage for discharging the molding material to the heating cylinder, an outlet of the introduction passage, and an inlet of the discharge passage. An intermediate passage, a piston movably accommodated in the intermediate passage so as to close the outlet of the introduction passage, and a notch formed at the front end of the piston for accommodating a molding material, and a front end is opened. Driving means for reciprocating the piston so that the groove portion and the position where the groove portion can face from the outlet of the introduction passage are defined as a backward limit position, and the position where the groove portion cannot face the outlet of the introduction passage is defined as a forward limit position And
The groove comprises a plurality of grooves have different capacities from each other, by turning the piston, exits morphism characterized by being configured to be able to face the one groove of the plurality to the outlet of the introduction path forming Machine material supply device. 4. The material supply device for an injection molding machine according to claim 3 , wherein the intermediate passage is an inclined passage that descends toward the discharge passage . The groove is configured to increase the depth of the groove toward the tip, morphism molding machine the material supply device according to claim 3, wherein a width of the groove toward the tip end is increased.

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