JP3515530B2 - Injection control device and injection control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection control device and an injection control method.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin as a molding material which is heated and melted in a heating cylinder is injected at a high pressure to fill the cavity space of a mold device, A molded product can be obtained by cooling and solidifying in the 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 the mold clamping cylinder advances and retracts the movable platen to close the mold. , Mold clamping and mold opening are performed.

On the other hand, the injection device is equipped with a heating cylinder for heating and melting the resin and an injection nozzle for injecting the melted resin, and a screw is rotatably and reciprocally movable in the heating cylinder. It is arranged. The resin is injected from the injection nozzle by advancing the screw by the drive unit arranged at the rear end,
The resin is measured by rotating it by the driving unit.

By the way, a resin charging portion is formed for supplying the resin to the heating cylinder. The resin charging part is
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.

The screw has a flight portion and a screw head disposed at the front end of the flight portion. The flight part includes a main body of the screw, that is, a flight spirally formed on the outer peripheral surface of the screw main body, and the flight forms a spiral groove. Further, in the flight part, from the rear to the front, a supply part to which the resin dropped from the hopper is supplied, a compression part to melt the supplied resin while compressing it, and a fixed amount of the melted resin A weighing unit 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 torque required to rotate the screw becomes large, the drive unit becomes large accordingly.

As the resin becomes denser,
Since shearing heat is generated in the resin, it becomes difficult to control the heating amount by the heater arranged in the heating cylinder.

The present invention solves the above-mentioned problems of the conventional injection apparatus and can reduce the frictional resistance between the inner peripheral surface of the heating cylinder and the molding material, which is necessary for rotating the screw. The torque can be reduced, the drive unit can be downsized, and the shearing heat generation can be prevented from occurring in the molding material, and the heating amount by the heater arranged in the heating cylinder can be easily controlled. It is an object of the present invention to provide an injection control device and an injection control method that can be performed.

[0010]

Therefore, in the injection control device of the present invention, a heating cylinder, a screw rotatably and reciprocally arranged in the heating cylinder, and the heating cylinder are provided in the heating cylinder. A molding material supply means for supplying a molding material, an injection pressure detection means for detecting an injection pressure in an injection step, a molding material pressure detection means for detecting a molding material pressure in front of the screw in the injection step, and the injection pressure. Pressure difference calculation processing means for calculating a pressure difference between the molding material pressure and the molding material pressure, and comparing the pressure difference with a preset threshold value, and if the pressure difference is larger than the threshold value, the molding material supply means When the pressure difference is less than or equal to the threshold value, the molding material supply amount changing processing means for increasing the supply amount of the molding material is reduced.

In the injection control method of the present invention, in the injection step, the injection pressure and the molding material pressure in front of the screw are detected, the pressure difference between the injection pressure and the molding material pressure is calculated, and the pressure difference is calculated. Compared with a preset threshold value, if the pressure difference is larger than the threshold value, reduce the amount of molding material supplied by the molding material supply means in the measuring step, and if the pressure difference is less than or equal to the threshold value, the supply amount in the measuring step. To increase.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a functional block diagram of an injection control device according to the first embodiment of the present invention.

In the drawing, 11 is a heating cylinder and 12
Is rotatably in the heating cylinder 11, and
A screw disposed so as to move forward and backward (moving in the left-right direction in the figure) 102 is a molding material supply means for supplying a resin (not shown) as a molding material to the heating cylinder 11,
Reference numeral 152 denotes a load cell as an injection pressure detecting means for detecting an injection pressure in the injection step, 30 denotes a molding material pressure detection for detecting a resin pressure as a molding material pressure in front of the screw 12 (left side in the drawing) in the injection step. A pressure sensor as means, 103 is a pressure difference calculation processing means for calculating a pressure difference between the injection pressure and the resin pressure, and 104 is a comparison between the pressure difference and a preset threshold value, and the pressure difference is larger than the threshold value. In this case, the amount of resin supplied by the molding material supply unit 102 is reduced, and when the pressure difference is equal to or less than a threshold value, the amount of resin supply is changed to increase the amount of the molding material.

FIG. 2 is a sectional view showing a main part of the injection apparatus according to the first embodiment of the present invention, and FIG. 3 is a conceptual view of the injection apparatus according to the first embodiment of the present invention.

In the figure, 11 is a heating cylinder as a cylinder member, 12 is a screw as an injection member which is rotatably and reciprocally (moved in the left-right direction in the drawing) disposed in the heating cylinder 11. 13 is an injection nozzle formed at 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, and 15 is near the rear end (the right end in the drawing) of the heating cylinder 11. A resin supply port 17 as a molding material supply port formed at a predetermined position is attached to the resin supply port 15 and is a resin charging part for supplying resin 16
Is a hopper that is attached to the resin feeding unit 17 and accommodates resin. Sheet-shaped heaters h1 to h3 are arranged on the outer periphery of the screw 12, and the resin can be heated and melted by energizing the heaters h1 to h3.

The screw 12 includes a flight portion 21,
And a screw head 27 disposed at the front end of the flight part 21. The flight part 21 is a flight 2 formed in a spiral shape on the outer peripheral surface of the screw body.
3, the flight 23 forms a spiral groove 24. Further, in the flight part 21, in order from the rear (right side in the drawing) to the front (left side in the drawing), the supply part P1 to which the resin dropped from the hopper 16 is supplied, and the supplied resin is melted while being compressed. Compressing part P2 and measuring part P3 for measuring the melted resin by a fixed amount
Is formed. The bottom of the groove 24, that is, the outer diameter of the screw body is made relatively small in the supply portion P1,
The compression portion P2 gradually increases from the rear to the front, and the weighing portion P3 relatively increases. Therefore, the gap (gap) between the inner peripheral surface of the heating cylinder 11 and the outer peripheral surface of the screw body is made relatively large in the supply portion P1 and gradually reduced in the compression portion P2 from the rear to the front, It is made relatively small at P3.

By the way, in order to supply resin to the heating cylinder 11, a resin charging section 17 as a molding material charging section.
The resin feeding portion 17 is disposed adjacent to the lower end of the hopper 16, and is a rotary type molding material member for intermittently feeding a set amount of resin. Is disposed adjacent to the lower end of the valve 18,
A cylindrical guide portion 19 for guiding the resin supplied by the supply valve 18 and a negative pressure generating portion 20 disposed adjacent to the lower end of the guide portion 19 are provided.

When the screw 12 is rotated in the forward direction during the measuring step, the resin in the hopper 16 is fed into the supply valve 1.
8 and the resin supply port 15 to the supply portion P1,
It is moved forward (moved to the left in the drawing) in the groove 24.
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 shape in the supply part P1, is in a semi-molten state in the compression part P2, and is completely melted in the measuring part P3 to be in a liquid state.

If the outer peripheral surface of the screw 12 and the inner peripheral surface of the heating cylinder 11 have the same roughness, the resin in the groove 24 is integrated with the screw 12 even if the screw 12 is rotated during the measuring process. It will be rotated and will not move forward. Therefore, normally, the heating cylinder 11
The inner peripheral surface of is made rougher than the outer peripheral surface of the screw 12.

When the screw 12 is moved forward during the injection step, the resin accumulated in front of the screw head 27 is injected from the injection nozzle 13 and is filled in the cavity space in the mold device (not shown). At this time, the check ring 37 is provided around the screw head 27 so that the resin stored in front of the screw head 27 does not flow backward.
And a backflow prevention device 36 consisting of a seal ring 38.

In the injection nozzle 13, the screw head 27 when the screw 12 is placed at the forward limit position in order to control the amount of resin supplied from the hopper 16 to the heating cylinder 11, that is, the supply amount. At a predetermined position further forward, for example, the position of the injection nozzle 13,
A pressure sensor 30 as a molding material pressure detecting means is provided so as to face the resin flow path 13a as a molding material passage.
The pressure sensor 30 is used for the screw 12 in the injection process.
The resin pressure as the molding material pressure on the front side is detected, and a sensor output corresponding to the resin pressure is generated.

The rear end of the heating cylinder 11 is attached to the front injection support 131, and the rear injection support 1 is spaced from the front injection support 131 by a predetermined distance.
32 are provided. And the front injection support 13
1 and the rear injection support 132 between the guide bar 133
And a pressure plate 134 is provided along the guide bar 133 so as to be movable back and forth. The front injection support 131 and the rear injection support 132 are fixed to a slide base (not shown) by bolts (not shown).

A drive shaft 135 is connected to the rear end of the screw 12, and the drive shaft 13
The bearing 5 is rotatably supported by the bearings 136 and 137 with respect to the pressure plate 134. And
In order to rotate the screw 12, an electric measuring motor 76 is provided as a first driving means, and the pulley 14 is provided between the measuring motor 76 and the drive shaft 135.
A first rotation transmission unit composed of 2, 143 and a timing belt 144 is provided. Therefore, by driving the measuring motor 76, the screw 12 can be rotated in the forward direction or the reverse direction. In the present embodiment, the electric measuring motor 76 is used as the first drive means, but a hydraulic motor may be used instead of the electric measuring motor 76. it can.

A ball screw 147 composed of a ball screw shaft 145 and a ball nut 146 screwed together is disposed behind the pressure plate 134, and the ball screw 147 converts rotational movement into linear movement. A movement direction conversion means is configured. The ball screw shaft 145 is rotatably supported by the bearing 148 with respect to the rear injection support 132, and the ball nut 146 is fixed to the pressure plate 134 via the plate 151 and the load cell 152 as injection pressure detecting means. To be done. Further, in order to move the screw 12 back and forth, an injection motor 77 as a second drive means is provided, and the injection motor 77 and the ball screw shaft 1
A second rotation transmission unit composed of pulleys 154 and 155 and a timing belt 156 is disposed between the first and second motors 45.
The load cell 152 detects the injection pressure in the injection process and generates a sensor output corresponding to the injection pressure.

Therefore, by driving the injection motor 77 and rotating the ball screw shaft 145, the ball nut 146 and the pressure plate 134 can be moved and the screw 12 can be moved forward or backward. In the present embodiment, the injection motor 77 is used as a means for moving the pressure plate 134, but an injection cylinder can be used instead of the injection motor 77. Also,
A drive unit is configured by the measuring motor 76, the injection motor 77, the ball screw 147, and the like.

Next, the resin injection section 17 will be described.

FIG. 4 is a front view showing the main part of the resin charging part according to the first embodiment of the present invention, and FIG. 5 is a sectional view showing the main part of the resin charging part according to the first embodiment of the present invention. FIG. 6 is a plan view showing a main part of a resin feeding part according to the first embodiment of the present invention.

In the figure, 18 is a supply valve, 19 is a guide portion, and 20 is a negative pressure forming portion. The supply valve 18
Includes a case 41 having a quadrangular cross section, and a shaft 43 as a valve main body rotatably supported in the case 41 having a circular cross section. A resin inlet 44 as a molding material inlet that is communicated with the hopper 16 (FIG. 2) is provided on the upper surface of the case 41, and a resin as a molding material outlet that is communicated with the guide portion 19 is provided on the lower surface of the case 41. The outlets 45 are formed on the same axis as each other. 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, and is supported by the small diameter portion 47 and 48 with respect to the case 41. Further, a pocket 49 as a molding material accommodating portion having a predetermined depth is formed at a predetermined position in the circumferential direction of the large diameter portion 46 at a position corresponding to the resin inlet 44 and the resin outlet 45, and the shaft is formed. By rotating 43, the pocket 49 is moved into the resin inlet 44.
Alternatively, it is selectively communicated with the resin outlet 45.

In the present embodiment, the large diameter portion 46 is
Although one pocket 49 is formed in each of the above, it is also possible to form two or more pockets at a plurality of positions in the circumferential direction of the large diameter portion 46 at the same pitch. In that case, since each pocket can be made shallow, fluctuations in the supply amount of the resin supplied to the heating cylinder can be reduced.

Then, adjacent to one end of the case 41, a supply valve (third part) for operating the supply valve 18 is provided.
A supply motor 51 as a driving means is attached, and the output shaft 52 of the supply motor 51 has the small diameter portion 4
It is fitted into the housing 8 and fixed to the shaft 43.
Therefore, by intermittently driving the supply motor 51, the shaft 43 is rotated, the pocket 49 is placed at a position communicating with the resin inlet 44, and the resin in the hopper 16 is accommodated in the pocket 49. ,continue,
The pocket 49 can be placed at a position communicating with the resin outlet 45, and the resin in the pocket 49 can be supplied to the guide portion 19 by a set amount. The supply motor 51 and the supply valve 18 constitute a molding material supply means 102 (FIG. 1).

The guide portion 19 is composed of an inner tube 53 made of glass and an outer tube 54 arranged at a predetermined distance radially outward from the inner tube 53, and the upper end of the inner tube 53 is It is opened so as to face the resin outlet 45.

Further, the negative pressure forming portion 20 includes an inner pipe 56,
And an outer pipe 57 arranged at a predetermined distance radially outward from the inner pipe 56, a flange 58 is attached to the lower end of the outer pipe 57, and the resin injection part 17 has the flange 58. It is fixed to the heating cylinder 11 via. 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 The inside of the heating cylinder 11 and the resin passage 31 is made airtight by the supply valve 18, and the negative pressure forming portion 2 is provided.
A negative pressure builds up at zero. Therefore, the inner pipe 56 and the outer pipe 5
An annular chamber 61 is formed between the heating cylinder 1 and
1 and the inside of the resin passage 31 are communicated with the annular chamber 61 at the lower end of the inner pipe 56. A suction port 62 is formed at a predetermined location of the outer tube 57, and a filter device 65 is connected to the suction port 62 via a suction pipe 64.

The filter device 65 comprises a porous inner tube 66,
And an outer pipe 67 arranged at a predetermined distance radially outward from the inner pipe 66, wherein the inner pipe 66 and the outer pipe 67 are provided.
A filter 68 is disposed between the filter 68 and. Also, the outer tube 6
A suction port 69 is formed at a predetermined position of 7, and a vacuum pump (not shown) as negative pressure generating means is connected to the suction port 69 via an opening / closing valve 71 and a suction pipe 72.

A level gauge 55 is disposed so as to face the lower end of the inner pipe 53.

Next, an injection control device for operating the injection device having the above construction will be described.

FIG. 7 is a block diagram showing an injection control device according to the first embodiment of the present invention, and FIG. 8 is a diagram showing plastic characteristics of the injection device according to the first embodiment of the present invention. In FIG. 8, 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. 7, 75 is a control unit, 51 is a supply motor, 76 is a metering motor, 77 is an injection motor,
78 is a vacuum pump connected to the suction port 69 (FIG. 4), 3
0 is a pressure sensor, 152 is a load cell, 81 is the position of the screw 12, that is, a screw position sensor as a screw position detecting means for detecting the screw position,
Reference numeral 82 is a metering speed sensor that detects the rotation speed of the metering motor 76, 83 is an injection speed sensor that detects the rotation speed of the injection motor 77, and 84 is a supply speed sensor that detects the rotation speed of the supply motor 51. Is.

First, when the controller 75 drives the vacuum pump 78, the air in the heating cylinder 11 and the resin passage 31 is sucked, and a negative pressure is generated in the heating cylinder 11. Next, the measurement control means (not shown) of the control unit 75 starts the measurement process, generates a measurement start signal and sends it to the measurement motor 76, and drives the measurement motor 76 to rotate the screw 12. Further, the measurement control means sends the measurement start signal to the supply motor 51 and drives the supply motor 51 to intermittently rotate the shaft 43. Along with that, the hopper 16
The resin inside is supplied into the resin passage 31 through the pocket 49 and further supplied to the supply portion P1 through the resin supply port 15. The resin supplied to the supply part P1 is the screw 1
Along with the rotation of 2, the groove 24 is advanced to become a semi-molten state in the compression section P2, and is completely melted into a liquid state in the measuring section P3, and is accumulated in front of the screw head 27.

During this time, the vacuum pump 78 is continuously driven to generate a negative pressure 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 found that the screw 12 has reached a predetermined measuring end position based on the signal from the screw position sensor 81, the measuring control means
The measuring process is completed, a measuring end signal is generated and sent to the measuring motor 76, and the driving of the measuring motor 76 is stopped to stop the rotation of the screw 12. Further, the measurement control means sends the measurement end signal to the supply motor 51 to stop the drive of the supply motor 51, thereby stopping the rotation of the shaft 43.

Next, the injection control means (not shown) of the controller 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 advance the screw 12. Let Along with this, the resin accumulated in front of the screw head 27 is injected from the injection nozzle 13.

By the way, in the measuring step, the amount of resin supplied to the supply part P1 by the resin injection part 17 and the amount of resin moved in the groove 24 and accumulated in front of the screw head 27. And are made equal. Therefore, when the injection process is started, the pressure difference calculation processing means 103 (FIG. 1) of the control unit 75 reads the sensor output of the load cell 152 and the sensor output of the pressure sensor 30, and the injection detected by the load cell 152. Resin pressure Pr detected by pressure Pi and pressure sensor 30
And the pressure difference ΔP ΔP = Pi−Pr is calculated. In this case, in the measuring step, the supply part P
If the resin state in 1 is dense, the injection pressure Pi increases in the injection process and the pressure difference ΔP increases. Further, if the resin state in the supply part P1 is sparse in the measuring step, the injection pressure Pi becomes low and the pressure difference ΔP becomes small.

Therefore, the molding material supply amount change processing means 104 of the control unit 75 compares the pressure difference ΔP with a preset threshold value ψP, and when the pressure difference ΔP is larger than the threshold value ψP, the groove 24. Since it can be seen that the resin inside is dense, the supply motor 5 in the weighing process
By lowering the rotation speed of No. 1, the supply amount is reduced and the state of the resin in the supply portion P1 is made sparse. Further, when the pressure difference ΔP is less than or equal to the threshold value ψP, it can be seen that the state of the resin in the supply part P1 is excessively sparse, and thus the supply speed is increased by increasing the rotation speed of the supply motor 51 in the measuring step. By increasing the amount, the state of the resin in the supply part P1 is set to a proper sparse state. In this case, the rotation speed of the supply motor 51 may be feedforward-controlled based on the speed command value or may be feedback-controlled based on the rotation speed detected by the supply speed sensor 84.

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%.

On the other hand, in the compression portion P2 and the measuring portion P3 of the screw 12, the resin state is made dense and the groove 2
4 is filled with 100% of resin. Then, the rearmost position of the portion where the groove 24 is filled with 100% of the resin is located substantially at the boundary between the compression portion P2 and the supply portion P1.

When the screw rotation speed is N and the screw retreat speed is Vr, the plasticizing capacity represented by the screw rotation speed N and the screw retreat speed Vr is determined by the model, size, standard, etc. of the injection device. Will fall on the lower side of the plasticizing ability standard line Ls shown in FIG. 8, that is, on the hatched portion. For example, in the plasticization capacity standard line Ls, the screw retreat speed Vr when the screw rotation speed N is the value n
Is a value v, when the screw rotation speed N is fixed at a value n, the screw retreat speed Vr is set to Vr <v by adjusting the rotation speed of the supply motor 51.

When the screw retreat speed Vr is fixed at 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 weighing is performed in the region on the low speed side and the high rotation side from the plasticizing capacity standard line Ls.

By setting in this way, the resin is supplied to the supply portion P only during the weighing process and in an amount necessary for the weighing.
Therefore, the resin is not stored in the resin passage 31.

As described above, in the supply section P1,
Since the state of the resin is sparse, it is possible to reduce the frictional resistance between the inner peripheral surface of the heating cylinder 11 and the resin in the measuring process. As a result, the torque required to rotate the screw 12 is reduced, and the drive unit can be downsized accordingly.

Further, since the state of the resin is sparse, it is possible to prevent the resin from generating heat due to shearing. Therefore, the heaters h1 to h arranged in the heating cylinder 11
The amount of heating by 3 can be easily controlled.

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

Further, the function of the supply part P1 is to mainly apply the resin supplied through the resin supply port 15 to the compression part P2.
Therefore, it is possible to shorten the supply portion P1 or form only the compression portion P2 and the weighing portion P3 in the flight portion 21. Therefore, the injection device can be downsized.

Since the supply amount is constant, the density of the resin to be filled can be constant.

Next, a second embodiment of the present invention will be described.

FIG. 9 is a cross-sectional view showing the main part of the resin charging section in the second embodiment of the present invention.

In the figure, 88 is a feed screw,
Reference numeral 89 is a guide. The feed screw 88 is
A case 91 having a quadrangular cross section and an auger 93 as a molding material member rotatably supported in the case 91 are provided to drive a supply motor 51 as a supply (third) drive means. The heating cylinder 11 serving as a cylinder member is made of resin (not shown) as a molding material and is continuously rotated with the rotation.
(Fig. 2). A resin inlet 94 as a molding material inlet that communicates with the hopper 16 is formed on the upper surface of the case 91, and a resin outlet 95 as a molding material outlet that communicates with the guide portion 89 is formed on the lower surface of the case 91. To be done. The auger 93 includes a main body portion 96 and a shaft portion 97 formed at a rear end (right end in the figure) of the main body portion 96, and the shaft portion 97 is fitted into the sleeve 101. The sleeve 101 is supported on the case 91 by bearings b1 to b3. The main body 96 is the main body of the auger 93, that is,
Flight 98 spirally formed on the outer peripheral surface of the auger body
And the flight 98 forms a spiral groove 99.

A supply motor 51 is mounted adjacent to one end of the case 91, and the supply motor 5
The output shaft 52 of No. 1 is fitted in the sleeve 101,
It is fixed to the shaft portion 97. Therefore, by driving the supply motor 51, the main body portion 96 can be rotated and the resin can be supplied to the guide portion 89 by the set amount. The molding material supply means 102 (FIG. 1) by the supply motor 51 and the feed screw 88.
Is configured.

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

[0060]

As described in detail above, according to the present invention, in the injection control device, the heating cylinder and the screw rotatably and reciprocally disposed in the heating cylinder, A molding material supply means for supplying a molding material to the heating cylinder, an injection pressure detection means for detecting an injection pressure in an injection step, and a molding material pressure detection means for detecting a molding material pressure in front of the screw in the injection step. The pressure difference calculation processing means for calculating the pressure difference between the injection pressure and the molding material pressure and the pressure difference and a preset threshold value are compared. If the pressure difference is larger than the threshold value, the molding material supply means When the supply amount of the molding material is reduced and the pressure difference is less than or equal to the threshold value, the supply amount of the molding material is changed to increase the supply amount.

In this case, when the pressure difference is larger than the threshold value,
The amount of resin supplied to the supply unit is reduced, and the state of the resin in the supply unit is made sparse. Therefore, it is possible to reduce the frictional resistance between the inner peripheral surface of the heating cylinder and the resin in the measuring step. As a result, the torque required to rotate the screw is reduced, and the drive unit can be downsized accordingly.

Further, since the state of the resin is sparse, it is possible to prevent the resin from generating heat due to shearing. Therefore, it is possible to easily control the heating amount by the heater arranged in the heating cylinder.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an injection control device according to a first embodiment of the present invention.

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

FIG. 3 is a conceptual diagram of an injection device according to the first embodiment of the present invention.

FIG. 4 is a front view showing a main part of a resin charging unit according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a main part of a resin charging unit according to the first embodiment of the present invention.

FIG. 6 is a plan view showing a main part of a resin charging unit according to the first embodiment of the present invention.

FIG. 7 is a block diagram showing an injection control device according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a plastic characteristic of the injection device according to the first embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a main part of a resin feeding part according to a second embodiment of the present invention.

[Explanation of symbols]

11 heating cylinder 12 screws 30 pressure sensor 102 molding material supply means 103 pressure difference calculation processing means 104 Molding material supply amount change processing means 152 load cell

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-241851 (JP, A) JP-A-53-11957 (JP, A) JP-A-2000-176958 (JP, A) JP-A-63-236618 (JP, A) JP-A-11-19990 (JP, A) Actually developed 54-17869 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/00-45 / 84

Claims (2)

(57) [Claims] 1. (a) a heating cylinder; (b) a screw rotatably and reciprocally arranged in the heating cylinder; and (c) a molding material for supplying a molding material to the heating cylinder. Supply means, (d) injection pressure detection means for detecting injection pressure in the injection step, (e) molding material pressure detection means for detecting molding material pressure in front of the screw in the injection step, and (f) Pressure difference calculation processing means for calculating the pressure difference between the injection pressure and the molding material pressure,
(G) comparing the pressure difference with a preset threshold value, if the pressure difference is larger than the threshold value, decrease the amount of molding material supplied by the molding material supply means, and if the pressure difference is less than or equal to the threshold value, An injection control device, comprising: a molding material supply amount change processing means for increasing the supply amount. 2. In the injection step, (a) the injection pressure and the molding material pressure in front of the screw are detected, (b) the pressure difference between the injection pressure and the molding material pressure is calculated, and (c) the pressure. Compare the difference with a preset threshold value, if the pressure difference is larger than the threshold value, reduce the amount of molding material supplied by the molding material supply means in the measuring step, and if the pressure difference is less than or equal to the threshold value, in the measuring step, An injection control method characterized by increasing the supply amount.