JP2003236885A - Molding material feeding system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize a frictional resistance between an inner surface of a heating cylinder and a molding material, stabilize a torque required to rotate and advance a screw, and prevent occurrence of a shearing heat in molding materials and contamination due to resin carbonization by properly controlling a quantity of the molding materials to be fed to an injection device. <P>SOLUTION: The system is equipped with a guide part 19 which is connected to a molding material feeding port 11 of a heating cylinder 11 having a screw inside which is installed to freely rotate and move back and forth, a weighing and feeding apparatus 18 which discharges a molding material and feeds it to the guide part, a charging apparatus to charge the molding material into the weighing and feeding apparatus 18 and a weighing and feeding controller which controls the weighing and feeding apparatus 18 to let the screw conduct a hunger weighing on the molding material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material supply device.

[0002]

2. Description of the Related Art Conventionally, in a molding machine such as an injection molding machine, a resin as a molding material heated and melted in a heating cylinder is injected at high pressure to fill a cavity space of a mold device. Then, a molded product is molded by cooling and solidifying in the cavity space.

The injection molding machine includes a mold device, a mold clamping device, and an injection device. The mold clamping device includes a fixed platen and a movable platen, and a mold clamping cylinder advances and retracts the movable platen to mold the mold. The machine is closed, closed and opened.

On the other hand, the injection device comprises a heating cylinder for heating and melting the resin, and an injection nozzle attached to the front end of the heating cylinder for injecting the melted resin, and the screw is provided in the heating cylinder. Is rotatably arranged and is movable back and forth. Then, the screw is moved forward by a drive unit arranged at the rear end to inject the resin from the injection nozzle, and the drive unit rotates the resin to measure the resin.

By the way, a resin charging section is formed for supplying resin to the heating cylinder.
Equipped with hopper, open / close valve, guide and level gauge,
The level gauge detects the resin level in the guide portion. Then, when the level of the resin decreases as the injection and measurement are repeated, the opening / closing valve is opened and the resin in the hopper is supplied to the guide portion.

Further, the screw includes a flight portion and a screw head arranged at the front end of the flight portion. The flight part includes a main body of the screw, that is, a flight formed in a spiral shape on an outer peripheral surface of the screw main body, and the flight forms a spiral groove. Further, in the flight part, in order from the rear to the front, a supply part to which the resin dropped from the hopper is supplied, a compression part that melts the supplied resin while compressing it,
And the measuring part which measures the melted resin by a fixed amount is formed.

[0007]

However, in the above-mentioned conventional injection device, the resin dropped from the hopper is accumulated in the supply part, and the state of the resin in the supply part becomes dense. The frictional resistance between the inner peripheral surface of the cylinder and the resin increases. as a result,
Since the frictional resistance is not always constant, the amount of resin injected changes.

As the resin becomes denser,
Since the resin is sheared, the resin is carbonized,
Contamination is mixed in the molded product.

The present invention solves the above-mentioned conventional problems,
By properly controlling the amount of molding material supplied to the injection device,
The frictional resistance between the inner peripheral surface of the heating cylinder and the molding material can be reduced, and the torque required for rotating and advancing the screw can be stabilized, and
It is possible to prevent shear insulation from occurring in the molding material,
An object of the present invention is to provide a molding material supply device capable of preventing contamination due to carbonization of resin.

[0010]

Therefore, in the molding material supply apparatus of the present invention, the molding material supply port of a heating cylinder internally provided with a screw rotatably and reciprocally arranged is connected. Guide part, a measuring and cutting device that cuts out the molding material and supplies it to the guide part, a charging device that charges the molding material into the measuring and cutting device, and a screw that starves the molding material. And a weighing and cutting-out control device that controls the weighing and cutting-out device.

In another molding material supply apparatus of the present invention, the charging device is a molding material dryer, and the measuring and cutting device is an accessory device of the molding material dryer.

In still another molding material supply apparatus of the present invention, the metering / cutting-out apparatus further includes a supply valve for intermittently cutting out the molding material with rotation.

In still another molding material supply apparatus of the present invention, the measuring and cutting apparatus further includes an opening / closing valve which is opened and closed intermittently by air pressure.

In still another molding material supply device of the present invention, the measuring and cutting control device controls the measuring and cutting device so as to cut out the molding material only while the screw is rotating. .

In still another molding material supply device of the present invention, the measuring and cutting control device controls the measuring and cutting device according to the amount of the molding material in the groove of the screw.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The molding material supply apparatus of the present invention can be applied to various apparatuses and methods, but in the present embodiment, for convenience of explanation, the case of being applied to an injection molding machine will be described.

FIG. 1 is a functional block diagram of a molding material supply apparatus according to the first embodiment of the present invention.

In the drawing, reference numeral 11 is a heating cylinder of an injection device, in which a screw 12, which will be described later, is rotatably and movably arranged (movable in the left-right direction in the drawing). Reference numeral 83 denotes a mold part including a mold device and a mold clamping device for performing mold closing, mold clamping and mold opening of the mold device, which is a molding material heated and melted in the heating cylinder 11. The resin is injected at high pressure to fill the cavity space of the mold apparatus, and is cooled and solidified in the cavity space to form a molded product. Reference numeral 82 is a drive unit for moving the heating cylinder 11 forward and backward, rotating the screw 12 in the heating cylinder 11, and moving the screw 12 forward and backward. Reference numeral 81 is an injection molding machine supporting portion on which the mold portion 83 and the driving portion 82 are mounted.

Reference numeral 17 denotes a resin dryer as a molding material dryer disposed above the injection device. here,
The resin dryer 17 functions as a charging device for charging a molding material. In addition, the resin dryer 17 includes a resin tank for storing a large amount of pellet-shaped resin and a device for drying the pellet-shaped resin stored in the resin tank, and a resin discharge pipe is provided at a lower end of the resin tank. A metering / cutting device 18 connected via 16 is provided. The measuring / cutting device 18 is preferably an auxiliary device of the resin dryer 17, but may be separate from the resin dryer 17. The measuring and cutting device 18 is a device for discharging, ie, cutting out, the pellet-shaped resin contained in the resin tank by a predetermined amount, and may be of any kind. In the embodiment, as will be described later, the shaft 43 is provided as a supply valve that intermittently cuts out the resin with rotation.

The outlet of the metering / cutting device 18 is connected to the heating cylinder 1 via a guide part 19 and a negative pressure forming part 20.
The resin cut out from the resin dryer 17 is supplied to the heating cylinder 11 by being connected to the resin supply port 15 described later. Here, in the guide section 19,
A level detector 55 including an upper level detector 55a and a lower level detector 55b for detecting the resin level is provided. Note that the guide portion 19 does not necessarily have to be negative pressure.

FIG. 2 is a sectional view of the injection apparatus according to the first embodiment of the present invention.

In the figure, 12 is the heating cylinder 11
A screw as an injection member, which is rotatably and forwardly and backwardly (movably in the left-right direction in the drawing) provided therein, 13 is an injection nozzle attached to the front end (the left end in the drawing) of the heating cylinder 11, 14 Is a nozzle port formed in the injection nozzle 13. The resin supply port 15 as a molding material supply port is formed at a predetermined position near the rear end (right end in the figure) of the heating cylinder 11. Further, planar heaters h1 to h3 are arranged on the outer periphery of the heating cylinder 11, and the resin can be heated and melted by energizing the heaters h1 to h3.

Here, the screw 12 comprises a flight portion 21 and a screw head 27 arranged at the front end of the flight portion 21. And the flight unit 21
Is provided with a flight 23 formed in a spiral shape on the outer peripheral surface of the screw main body, and a spiral groove 24 is formed by the flight 23.
Is formed. Further, to the flight part 21, from the rear (right side in the drawing) to the front (left side in the drawing), a supply part P1 to which the resin dropped from the resin discharge pipe 16 is supplied in order, and while compressing the supplied resin. A compression part P2 for melting and a measuring part P3 for measuring the melted resin by a fixed amount are formed. The bottom of the groove 24, that is, the outer diameter of the screw body is relatively small at the supply portion P1, gradually increased from the rear to the front at the compression portion P2, and relatively large at the measuring portion P3. Therefore, the gap between the inner peripheral surface of the heating cylinder 11 and the outer peripheral surface of the screw main body is equal to the supply portion P.
1 is relatively large, is gradually reduced in the compression portion P2 from the rear to the front, and is relatively small in the weighing portion P3.

During the measuring step, the screw 12 is
Is rotated in the forward direction, the resin in the resin dryer 17 is supplied from the resin supply port 15 to the supply portion P1 via the measuring and cutting device 18, and moves forward in the groove 24 (to the left in the drawing). Be moved). Along with that, the screw 12 is retracted (moved to the right in the figure), and the resin is stored in front of the screw head 27. The resin in the groove 24 has a pellet-like shape in the supply part P1, becomes a semi-molten state in the compression part P2, and the measuring part P3.
At, it is completely melted and becomes liquid.

Here, if the roughness of the outer peripheral surface of the screw main body and the inner peripheral surface of the heating cylinder 11 are equal to each other, even if the screw 12 is rotated during the measuring step, the resin in the groove 24 will not react with the screw 12. It will be rotated integrally,
Do not move forward. Therefore, normally, the inner peripheral surface of the heating cylinder 11 is processed to be rougher than the outer peripheral surface of the screw body.

During the injection process, the screw 12 is
When is moved forward, the resin stored in front of the screw head 27 is injected from the injection nozzle 13 and filled in the cavity space in the mold device (not shown). At this time,
A check ring 37 is provided around the screw head 27 so that the resin accumulated in front of the screw head 27 does not flow backward.
And a backflow prevention device 36 consisting of a seal ring 38. In addition, in order to rotate the screw 12 at the time of the measuring step, a measuring motor (not shown) serving as a first driving means, and in order to advance the screw 12 during the injection step, a not-illustrated injection motor serving as a second driving means. And a measuring motor, an injection motor,
The drive unit is composed of a transmission mechanism (not shown).

Next, the weighing and cutting device 18 and the guide portion 19
The negative pressure forming section 20 will be described.

FIG. 3 is a front view showing the weighing and cutting device, the guide portion and the negative pressure forming portion according to the first embodiment of the present invention, and FIG. 4 is the weighing and cutting device according to the first embodiment of the present invention. ,
FIG. 5 is a cross-sectional view showing the guide portion and the negative pressure forming portion, and FIG. 5 is a plan view showing the weighing and cutting device, the guide portion and the negative pressure forming portion according to the first embodiment of the present invention.

In the present embodiment, as shown in FIG. 4, the metering and cutting device 18 includes a shaft 43 as a supply valve for intermittently cutting the molding material with rotation, and a supply having a rectangular cross section. A case 41 as a valve case is provided. The shaft 43 is rotatably supported in the case 41 and has a circular cross section. And
A resin inlet 44 serving as a molding material inlet that communicates with the resin discharge pipe 16 is formed on the upper surface of the case 41, and a molding material outlet that communicates with the guide portion 19 is formed on the lower surface of the case 41. The resin outlet 45 is formed on the same axis as the resin inlet 44. The shaft 43 includes a large-diameter portion 46 and small-diameter portions 47 and 48 formed at both ends of the large-diameter portion 46. The small-diameter portion 47,
It is supported with respect to the case 41 by 48. Further, at a predetermined position in the circumferential direction of the large diameter portion 46, a pocket 49 as a molding material storage portion having a predetermined depth is formed at a position corresponding to the resin inlet 44 and the resin outlet 45. By rotating the shaft 43, the pocket 49 is selectively communicated with the resin inlet 44 or the resin outlet 45.

In this embodiment, one pocket 49 is formed on the large diameter portion 46, but the large diameter portion 4
It is also possible to form two or more pockets at the same pitch at a plurality of positions in the circumferential direction of 6. In that case, since each pocket can be made shallow, it is possible to reduce the variation in the cutout amount.

Then, adjacent to one end of the case 41, a supply motor 51 as a third driving means for operating the weighing and cutting device 18 is attached, and an output shaft 52 of the supply motor 51 is , Is fitted into the small diameter portion 48 and fixed to the shaft 43. Therefore,
By intermittently driving the supply motor 51, the shaft 43 is rotated and the pocket 49 is placed at a position communicating with the resin inlet 44.
The resin in 6 is accommodated in the pocket 49, and then the pocket 49 is placed at a position communicating with the resin outlet 45, and the resin in the pocket 49 is supplied to the guide portion 19 by a set amount. That is, it can be cut out.

Here, the guide portion 19 includes an inner tube 53 made of glass, and an outer tube 54 radially outwardly of the inner tube 53 with a predetermined distance therebetween. Tube 5
The upper end of 3 is opened so as to face the resin outlet 45. A level detector 55 that detects the level of the resin is disposed so as to face the inner pipe 53. In this case, the level detector 55 is an upper level detector 55 that detects that the resin filled in the inner pipe 53 is at a high level.
a and a lower level detector 55b for detecting that the resin is at a low level. If the level detector 55 can distinguish whether the resin is at a high level or a low level,
It may be a single detector.

Further, the negative pressure forming portion 20 includes an inner pipe 56,
And an outer pipe 57 arranged at a predetermined distance radially outward of the inner pipe 56. Here, the outer tube 57
A flange 58 is attached to the lower end of the negative pressure forming section 20, and the negative pressure forming section 20 is fixed to the heating cylinder 11 via the flange 58. The lower end of the inner pipe 53 and the upper end of the inner pipe 56 are brought into contact with each other, and a resin passage 31 as a molding material passage communicating with the inside of the heating cylinder 11 is formed in the inner pipe 53 and the inner pipe 56. It Further, the inside of the heating cylinder 11 and the resin passage 31 are made airtight by the measuring and cutting device 18, and a negative pressure is formed in the negative pressure forming portion 20. Therefore, the annular chamber 6 is provided between the inner pipe 56 and the outer pipe 57.
1, the inside of the heating cylinder 11 and the resin passage 3 are formed.
1 is communicated with the annular chamber 61 at the lower end of the inner pipe 56, as shown in FIG. And the outer tube 5
7, a suction port 62 is formed at a predetermined position, and the suction port 62
A filter device 65 is connected to the through a suction pipe 64.

The filter device 65 comprises an inner pipe 66 having a large number of holes, and an outer pipe 67 arranged radially outward of the inner pipe 66 with a predetermined distance.
A filter 68 is arranged between the inner pipe 66 and the outer pipe 67. The suction port 6 is provided at a predetermined position of the outer tube 67.
As shown in FIG. 5, a vacuum pump 78, which will be described later, as negative pressure generating means is connected to the suction port 69 via the opening / closing valve 71 and the suction pipe 72. Therefore, by driving the vacuum pump 78, a negative pressure is generated in the heating cylinder 11.

Next, a control device for operating the molding material supply device having the above construction will be described.

FIG. 6 is a block diagram showing a control device according to the first embodiment of the present invention, FIG. 7 is a diagram showing a starvation measurement state according to the first embodiment of the present invention, and FIG. 8 is a view showing the present invention. The figure which shows the state of normal measurement in 1st Embodiment,
FIG. 9 is a diagram showing a plastic characteristic of the injection device according to the first embodiment of the present invention. In FIG. 7, the horizontal axis represents the rotation speed of the screw 12 (FIG. 2), that is, the screw rotation speed N, and the vertical axis represents the backward speed of the screw 12, that is, the screw backward speed Vr.

In FIG. 6, reference numeral 75 denotes an arithmetic means such as a CPU and MPU, a storage means such as a semiconductor memory and a magnetic disk, an input means such as a keyboard and a touch panel, a CRT,
The control unit includes a display unit such as a liquid crystal display, an input / output interface, and the like, and functions as a measurement / cutout control device. The control unit 75 may be independently configured and exist, or may be integrally configured with a control device for controlling other devices such as an injection molding machine. It may be one of the systems built in another control device. In the present embodiment, a case will be described in which the control unit 75 is formed integrally with a control device for operating the injection device.

Here, reference numeral 80 is a database in which data such as cut-out rotation speed for normal measurement and cut-out rotation speed for starvation measurement are stored. The database 80
May be built in a storage unit included in the control unit 75, or may be built in an external storage unit independent of the control unit 75.

Reference numeral 76 denotes a screw rotation motor, 7
Reference numeral 7 is an injection motor, and 78 is a vacuum pump connected to the suction port 69. Further, 12a is a position of the screw 12, that is, a screw position sensor as a screw position detecting means for detecting the screw position, 76a is a screw rotation speed sensor for detecting the rotation speed of the screw rotation motor 76, and 77a is an injection motor. An injection speed sensor for detecting the rotation speed of 77, 51a is a supply speed sensor for detecting the rotation speed of the supply motor 51.

First, when the controller 75 drives the vacuum pump 78, the inside of the heating cylinder 11 and the resin passage 31 (FIG. 4).
Is sucked in, and a negative pressure is generated in the heating cylinder 11. Next, the control unit 75 starts the measuring process, generates a measuring start signal, and causes the screw rotation motor 7 to operate.
6, and the screw 12 is rotated by driving the screw rotation motor 76. Further, the control unit 75 sends the weighing start signal to the supply motor 51,
The shaft 4 is driven by driving the supply motor 51.
3. Rotate 3 intermittently. Along with that, the resin dryer 1
The resin in 7 is cut out into the resin passage 31 through the pocket 49, and is further supplied to the supply portion P1 through the resin supply port 15. The resin supplied to the supply part P1 is
As the screw 12 rotates, it moves forward in the groove 24, becomes a semi-molten state in the compression section P2, is completely melted in the measuring section P3 and becomes a liquid, and is stored in front of the screw head 27.

During this time, the vacuum pump 78 continues to be driven and a negative pressure is generated in the heating cylinder 11. Therefore, since the air that has entered the heating cylinder 11 and the resin passage 31 and the gas that is generated as the measurement is performed are discharged, it is possible to prevent the resin burning.

Subsequently, when it is determined that the screw 12 has reached the predetermined measurement end position based on the signal from the screw position sensor 12a, the control unit 75 ends the measurement process and outputs the measurement end signal. It is generated and sent to the screw rotating motor 76, and the rotation of the screw 12 is stopped by stopping the driving of the screw rotating motor 76. Further, the control unit 75 sends the measurement end signal to the supply motor 51 to stop the driving of the supply motor 51, thereby stopping the rotation of the shaft 43 and stopping the resin cutting.

Next, the control unit 75 starts the injection process, generates an injection start signal and sends it to the injection motor 77, and drives the injection motor 77 to move the screw 12 forward. Along with this, the screw head 2
The resin accumulated in front of 7 is injected from the injection nozzle 13.

By the way, the amount of resin cut out from the resin dryer 17 and supplied to the supply portion P1 via the resin supply port 15 is controlled by the number of rotations of the shaft 43. That is, the control unit 75 accesses the database 80, acquires the number of rotations for starvation measurement stored in the database 80, and drives the supply motor 51 to rotate the shaft 43. This allows the screw 12 to starve the resin. It is also possible to manually input without accessing the database 80.

Here, the starvation measurement means that, as shown in FIG. 7, the resin is not accumulated in the resin supply port 15 and the groove 24 of the screw 12 is not filled with the resin in the supply portion P1. In this state, the screw 12 measures resin. On the other hand, the normal measurement means that the resin is accumulated in the resin supply port 15 and the groove 24 of the screw 12 is filled with the resin in the supply portion P1 as shown in FIG. The resin is being measured. 7 and 8, reference numeral 88 indicates a resin.

In the normal measurement state, the resin is accumulated in the supply section P1 and the resin state in the supply section P1 becomes dense, so that the frictional resistance between the inner peripheral surface of the heating cylinder 11 and the resin is increased in the measurement step. As a result, the torque required to rotate the screw 12 increases. Further, also in the injection process, since the frictional resistance between the inner peripheral surface of the heating cylinder 11 and the resin is large, the thrust required to move the screw 12 forward is large. Furthermore, since the frictional resistance is not always constant, the amount of resin injected changes.

On the other hand, in the state of starvation measurement,
Since the resin does not accumulate in the supply part P1 and the state of the resin in the supply part P1 becomes sparse, the frictional resistance between the inner peripheral surface of the heating cylinder 11 and the resin becomes small in the measuring process, and the screw 12 is rotated. The torque required for is small. Further, also in the injection process, since the frictional resistance between the inner peripheral surface of the heating cylinder 11 and the resin is small, the screw 1
The thrust required to move 2 forward may be small. Further, since the frictional resistance is constant, the amount of injected resin does not change.

Here, the rotation speed of the shaft 43 for the starvation measurement can be set in advance by preliminarily operating the injection molding machine.

First, the injection molding machine is continuously operated in the normal measurement state. In this case, the resin is filled inside the inner pipe 56 and the inner pipe 53. Then, when the screw 12 reaches a predetermined measuring end position and the measuring process is completed and the shaft 43 rotates to cut out the resin, the resin filled in the inner pipe 56 and the inner pipe 53 is removed. Level increases. Then, the upper level detector 5 in which the resin in the glass inner tube 53 is arranged so as to face the inner tube 53
When the detection level of 5a is reached, the control section 75 receives the detection signal of the upper level detector 55a, and the shaft 43
To stop the resin cutting.

On the other hand, when the measuring process is started again, the screw 12 rotates, so that the resin supplied to the supply portion P1 is fed into the groove 24 of the screw 12. As a result, the level of the resin filled inside the inner pipe 56 and the inner pipe 53 is lowered. When the resin in the glass inner tube 53 reaches the detection level of the lower level detector 55b arranged so as to face the inner tube 53, the control unit 7
5 receives the detection signal of the lower level detector 55b,
The shaft 43 is rotated to start cutting out the resin.

In the case of normal weighing, the above-mentioned operation is repeated, and the resin level in the glass inner tube 53 is detected by the upper level detector 55a and the lower level detector 5.
It is kept to be between the detection level of 5b. As a result, the resin is accumulated in the resin supply port 15, and the groove 24 of the screw 12 in the supply portion P1 is kept filled with the resin. Here, the screw 1 during the weighing process
The time of two rotations, that is, the measuring time T1 is measured. Further, the plasticizing ability is calculated from the measuring time T1 and the weight of the molded product. In this case, the number of rotations of the shaft 43 for starvation measurement corresponding to the plasticization capacity is stored in the database 80 based on the plasticization capacity, and the shaft 43 corresponding to a desired starvation measurement ratio. Number of revolutions R
1 is derived from the database 80. The rotation speed R1 of the shaft 43 for starvation measurement is lower than the rotation speed R2 of the shaft 43 during normal measurement. Here, the cut-out rotation speed R1 for starvation measurement may be arbitrarily set as long as the condition of R1 <R2 is satisfied, but if it is too small, the supply amount of the resin in the groove 24 of the screw 12 becomes small. If it is too large, the time required for the weighing process becomes long. Instead of the method of deriving the starvation measurement, for example, 1.2 times the normal measurement time T1 is calculated, and the measurement time T2 is calculated.
The rotation speed of the shaft 43 is adjusted so that the rotation speed becomes (the rotation speed becomes smaller than that during normal measurement). Once the rotation speed is determined, starvation measurement is performed at that rotation speed thereafter.

As described above, the control unit 75 accesses the database 80, acquires the cut-out rotation speed for starvation measurement stored in the database 80, and waits until the screw 12 reaches the measurement end position. Only resin dryer 17
The resin inside is cut out and supplied to the supply part P1. As a result, in the supply portion P1, the state of the resin is made sparse, and the groove 24 is not filled with the resin 100%.

On the other hand, in the compression portion P2 and the measuring portion P3, the resin state is made dense, and the resin is filled in the groove 24 by 10%.
0 [%] is satisfied. Then, the resin in the groove 24 is 100
[%] The rearmost position of the filled portion is located substantially at the boundary between the compression portion P2 and the supply portion P1.

The plasticizing capacity represented by the screw rotation speed N and the screw retreat speed Vr depends on the model, size, standard, etc. of the injection device, but is lower than the plasticizing capacity standard line Ls shown in FIG. That is, it comes to fit in the hatched portion. For example, in the plasticizing capacity standard line Ls, when the screw retreat speed Vr is the value v when the screw rotation speed N is the value n, when the screw rotation speed N is fixed at the value n, the supply motor 5
By adjusting the rotation speed of 1, the screw retreat speed Vr is set to Vr <v.

When the screw retreat speed Vr is fixed to the value v, the screw rotation speed N is set to N> n by adjusting the rotation speed of the supply motor 51. That is, the plasticizing ability is lower than the plasticizing ability standard line Ls, and the measurement is performed in the low speed side and high rotation side regions.

By setting in this way, the resin is supplied to the supply part P1 only during the measuring process and in an amount necessary for the measurement, so that the state of the resin is sparse in the supply part P1 and The resin in 24 is not filled with 100%.

Therefore, in the supply portion P1, the resin state is made sparse, so that the frictional resistance between the inner peripheral surface of the heating cylinder 11 and the resin can be reduced in the measuring step.

Further, since the frictional resistance is constant, the amount of injected resin does not fluctuate and the molding is stable.

Furthermore, since the state of the resin is sparse, it is possible to prevent shear heat insulation from occurring in the resin. Therefore, carbonization of the resin can be prevented, and contamination of the molded product can be prevented.

Since a negative pressure is generated in the heating cylinder 11, the resin does not come into contact with air even if the resin state is sparse. Therefore, it is possible to prevent the resin from being oxidized by the air.

Next, a second embodiment of the present invention will be described. It should be noted that description of the same structure and the same operation as those of the first embodiment will be omitted.

FIG. 10 is a schematic view showing a measuring and cutting device of a resin dryer according to the second embodiment of the present invention.

In the figure, 91 is an opening / closing valve case, 96 is a resin introducing pipe whose inlet end is connected to the resin discharge pipe 16 and whose outlet end is connected to the opening / closing valve case 91, and 92 is arranged in the opening / closing valve case 91. The open / close valve opens and closes the outlet end of the resin introducing pipe 96. The outlet of the on-off valve case 91 is
Through the guide portion 19, the resin supply port 1 of the heating cylinder 11
5, the resin cut out from the resin dryer 17 is supplied to the heating cylinder 11.

Reference numeral 93 is an air cylinder device for driving the on-off valve 92.
The piston 93a is connected to the connecting rod 92a of the on-off valve 92. A high pressure air supply pipe 94 connected to a high pressure air supply source (not shown) is branched into a branch pipe 94a and a branch pipe 94b via an electromagnetic switching valve 95. The branch pipe 94a and the branch pipe 94b are respectively connected to two pressure chambers formed on both sides of the piston 93a of the air cylinder device 93. As a result, the electromagnetic switching valve 95 is operated, and the high pressure air supplied from the high pressure air supply source via the high pressure air supply pipe 94 is supplied to the branch pipe 94.
The piston 93a can be advanced and retracted to selectively open and close the on-off valve 92 by selectively circulating it through the a or the branch pipe 94b.

A high-pressure air supply pipe 86 connected to a high-pressure air supply source (not shown) is connected to the resin introducing pipe 96 via an electromagnetic opening / closing valve 87. Here, the electromagnetic opening / closing valve 87 is configured to open and close together with the opening / closing valve 92. Therefore, the opening / closing valve 92 is opened and the resin in the resin dryer 17 is filled with the resin discharge pipe 16 and the resin introduction pipe 96.
High-pressure air is blown into the resin introduction pipe 96 when flowing into the on-off valve case 91 through the above. Therefore, the resin flows into the on-off valve case 91 without staying or clogging in the resin introducing pipe 96, a portion between the outlet end of the resin introducing pipe 96 and the on-off valve 92, or the like. .

As described above, in the present embodiment, the weighing / cutting-out device 18 includes the opening / closing valve 92 driven by the air cylinder device 93. Therefore, the resin can be easily cut out by operating the electromagnetic switching valve 95 and changing the flow of the high pressure air supplied to the air cylinder device 93.

Next, a third embodiment of the present invention will be described. It should be noted that description of the same structure and the same operation as those of the first and second embodiments will be omitted.

FIG. 11 is a sectional view of an injection device according to the third embodiment of the present invention.

In this case, as shown in the drawing, the heating cylinder 11 when the screw 12 is placed at the forward limit position.
At a position corresponding to the supply portion P1 in front of the resin supply port 15 as the molding material supply port (left side in the drawing).
The three photosensors 59 as molding material detecting means are arranged facing the heating cylinder 11 at a predetermined pitch.
Each of the photosensors 59 detects the resin in the groove 24 in the supply portion P1 and generates a sensor output proportional to the amount of resin in the groove 24.

Then, in the weighing process, the control unit 75
Receives the sensor output of each photosensor 59, refers to a supply motor rotation speed table (not shown) stored in the database 80, reads the target rotation speed of the supply motor 51 corresponding to the sensor output, and supplies the supply motor. 5
The supply motor 51 is driven so that the rotation speed of 1 becomes the target rotation speed, and the amount of resin cut out by the measuring / cutting device 18 is set. In this case, the target rotation speed is lower than the rotation speed of the supply motor 51 corresponding to the normal weighing state. Therefore, the cut-out amount of the resin by the measurement cut-out device 18 becomes the cut-out amount for starvation measurement. The rotation speed of the supply motor 51 is the supply speed sensor 51a.
Is detected and feedback control is performed.

As a result, in the supply portion P1, the state of the resin is sparse, and the groove 24 is not filled with the resin by 100%.

As described above, in the present embodiment, the measuring / cutting-out device 18 detects the resin in the groove 24 in the supply portion P1 and the resin-drying device 17 by the cutting-out amount for starvation measurement.
The resin inside is cut out and supplied to the supply part P1. Therefore, the state of the resin in the supply part P1 can be appropriately controlled. Also, the resin dryer 1
Since the measuring and cutting device 18 of No. 7 is used, no special resin cutting device is required.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0074]

As described above in detail, according to the present invention, in the molding material supplying apparatus, the molding material supplying apparatus for the heating cylinder having the screw disposed rotatably and movable back and forth is provided. A guide part connected to the mouth, a measuring and cutting device that cuts out the molding material and supplies it to the guide part, a charging device that charges the molding material into the measuring and cutting device, and the screw starves the molding material. And a weighing and cutting control device that controls the weighing and cutting device so as to weigh.

In this case, in the screw supply section,
Since the state of the resin is made sparse, the frictional resistance between the inner peripheral surface of the heating cylinder and the resin can be reduced in the measuring step.

Therefore, since the frictional resistance is constant, the amount of injected resin does not fluctuate and the molding is stable.

Further, since the resin state is made sparse, it is possible to prevent shear heat insulation from occurring in the resin. Further, since the carbonization of the resin can be prevented, it is possible to prevent contamination of the molded product.

In the molding material supply apparatus, the charging device is a molding material dryer, and the measuring / cutting device is an accessory device of the molding material dryer.

Since it is not necessary to specially prepare the measuring and cutting device, the manufacturing cost of the molding material supplying device can be reduced.

In still another molding material supply device, the measuring and cutting control device controls the measuring and cutting device so as to cut out the molding material for a predetermined time.

In this case, since the operation of the weighing and cutting device is simple, a normal weighing and cutting device such as an auxiliary device of the molding material dryer can be used.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a molding material supply device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the injection device according to the first embodiment of the present invention.

FIG. 3 is a front view showing a weighing and cutting device, a guide portion, and a negative pressure forming portion according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a weighing and cutting device, a guide portion, and a negative pressure forming portion according to the first embodiment of the present invention.

FIG. 5 is a plan view showing a weighing and cutting device, a guide portion, and a negative pressure forming portion according to the first embodiment of the present invention.

FIG. 6 is a block diagram showing a control device according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a state of starvation measurement in the first embodiment of the present invention.

FIG. 8 is a diagram showing a normal weighing state according to the first embodiment of the present invention.

FIG. 9 is a diagram showing a plastic characteristic of the injection device according to the first embodiment of the present invention.

FIG. 10 is a schematic view showing a weighing and cutting device of a resin dryer according to a second embodiment of the present invention.

FIG. 11 is a sectional view of an injection device according to a third embodiment of the present invention.

[Explanation of symbols]

11 heating cylinder 12 screws 15 Resin supply port 17 resin dryer 18 Weighing and cutting device 19 Information Department 43 shaft 71, 92 open / close valve 75 Control unit 88 resin

Claims (6)

[Claims] 1. A guide part connected to a molding material supply port of a heating cylinder having a screw rotatably and advancing and retracting therein, and (b) cutting out the molding material to obtain the molding material. A measuring and cutting device for supplying to the guide portion, and (c) a charging device for charging the molding material into the measuring and cutting device,
(D) A molding material supply device, characterized in that the screw comprises a measuring and cutting control device that controls the measuring and cutting device so as to starve and measure the molding material. 2. The charging device is a molding material dryer,
The molding material supply device according to claim 1, wherein the measuring and cutting device is an auxiliary device of the molding material dryer. 3. The metering and cutting device comprises a supply valve for intermittently cutting the molding material with rotation.
The molding material supply apparatus according to. 4. The molding material supply apparatus according to claim 1, wherein the measuring and cutting device includes an opening / closing valve that opens and closes intermittently by air pressure. 5. The measuring / cutting-out control device according to claim 1, wherein the measuring / cutting-out control device controls the measuring / cutting-out device so as to cut out the molding material only while the screw is rotating. Molding material supply device. 6. The molding material according to claim 1, wherein the measuring / cutting-out control device controls the measuring / cutting-out device in accordance with the amount of the molding material in the groove of the screw. Supply device.