JP4385193B2 - Injection molding method in injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides an injection molding in an injection molding machine that supplies a molten resin to a tip portion in a heating cylinder of an injection device and measures the molten resin, and injects the measured molten resin into a mold by an injection member. It is about the method.
[0002]
[Prior art]
Conventionally, an injection screw has been inserted into a heating cylinder of an injection device so as to be movable in the axial direction and rotatable in the circumferential direction, and introduced into the heating cylinder from the base end side of the heating cylinder while rotating the injection screw. The plastic material is plasticized, the molten resin is supplied to the tip side in the heating cylinder and weighed, and the metered resin is injected into a mold clamped by a mold clamping device by advancing the injection screw. In the injection molding machine, in the injection process, the injection screw is rotated while applying back pressure to perform a molten resin supply operation for a predetermined time, and the molten resin is filled into the mold by this supply operation. An injection molding method is known in which an injection operation by advancing the injection screw is performed after the supply operation is completed to perform a filling step and a pressure holding step.
[0003]
  However, the injection molding method in the injection molding machine is employed to supplement the injection amount with respect to the volume of the molding cavity of the mold in the injection molding of a large thick molded product. Therefore, there is a problem that the surface finish of the molded product filled by the supply operation is not good. It was.
  Therefore, it is necessary to control the filling speed to multiple by changing the number of rotations of the injection screw according to the cross-sectional area of the resin passage and the molding cavity in the mold.The moldThere have been proposed a flow mold molding method for filling a molten resin into an injection molding method and an injection molding method for repeating injection molding with a molten resin metering operation and an injection operation by advancing an injection screw for one molded product a plurality of times. (For example, refer to Patent Document 1 and Patent Document 2).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-261085
[Patent Document 2]
JP 2000-343571 A
[0005]
[Problems to be solved by the invention]
  However, in the proposed flow molding method,The filling operationBecause only the mold is filled with molten resinAnd thenIn addition to the long molding cycle time, there is a limit to improving the surface of the molded product. In the injection molding method in which the weighing operation and the injection operation are repeated, an injection screw is used for one molded product. Since the injection stroke between the measurement completion position and the most advanced position is reciprocated a plurality of times, there is still a problem that the molding cycle time becomes long.
[0006]
The present invention has been made in view of the above circumstances, and a molded product including a thick portion, a thin portion, a portion where the surface is important, etc., improve transferability and improve the surface finishing accuracy, It is another object of the present invention to provide an injection molding method in an injection molding machine that can perform injection molding efficiently.
[0007]
[Means for Solving the Problems]
  The present invention is characterized by the following points in order to solve the above problems.
  That is, in the injection molding method according to the first aspect of the present invention, the molten resin is supplied to the tip portion in the heating cylinder of the injection apparatus and measured, and the measured molten resin is injected into the mold by the injection member. In the injection molding method in an injection molding machine to obtain a molded product, in the injection step, the injection operation of the molten resin into the mold by advance to the target position within the injection stroke of the injection member,From the target position to the retracted position of the injection memberThe supply operation of filling the mold while supplying molten resin to the tip of the heating cylinder with back pressure applied to the injection member is repeated several times.And thenThe pressure holding operation in the pressure holding process is performed after the final injection operation by the advance of the injection member.The plurality of target positions and the retreat positions are positions that are gradually advanced toward the injection completion position that completes filling of the mold, and the retreat positions are measured more than the target positions immediately before It is a position retracted to the completion position sideIt is characterized by that.
[0008]
  An injection molding method in an injection molding machine according to claim 2 is the injection molding method according to claim 1, wherein the supply operation is started when the injection member moves forward to the target position, and a set time elapses or the injection is performed. The member retracted by a set distanceOf the retracted positionEnds at the same time, and the next injection operation starts at the same time as the supply operation ends.To doIt is characterized by.
[0009]
  The injection molding method for an injection molding machine according to claim 3 is the injection molding method according to claim 1 or 2, wherein after the pressure-holding step, back pressure is applied to the injection member at a pressure higher than the pressure at the final stage. StateHeated withIt is characterized by starting the measurement of the molten resin into the cylinder.
[0010]
The injection molding method in the injection molding machine according to claim 4 is the injection molding method according to any one of claims 1 to 3, wherein the injection molding machine has an injection screw as an injection member in the heating cylinder. It consists of an inline screw type injection molding machine inserted in the axial direction of the machine and rotatably in the circumferential direction, and plasticizing the resin introduced to the base end side of the heating cylinder by the rotation of the injection screw It is characterized by doing.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an injection molding method in the injection molding machine according to the present invention will be described.
First, an example of an electric injection molding machine for carrying out the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes an electric injection molding machine provided with a mold clamping device 2 and an injection device 3 on a machine base 4. The mold clamping device 2 includes a stationary platen 5 and a movable platen 7 supported by a plurality of tie bars 6 attached to the stationary platen 5. The movable platen 7 is fixed by a mold clamping mechanism 8 such as a toggle mechanism. By moving forward and backward with respect to the board 5, the mold K (fixed mold K1, movable mold K2) fixed to the fixed board 5 and the movable board 7 is opened, closed, and clamped.
[0012]
The injection device 3 includes a front plate 10 fixed to a slide base 9 and supported by a machine base 4, a rear plate 12 connected to the front plate 10 by a guide rod 11 and fixed to the slide base 9, and the front plate. A heating cylinder 13 fixed to 10, an injection screw (injection member) 14 inserted into the heating cylinder 13 so as to be axially movable and rotatable in the circumferential direction, a front plate 10 and a rear plate 12, And a pusher plate 15 that is supported by the guide rod 11 and rotatably supports a proximal end portion of the injection screw 14, and is rotatably supported by the rear plate 12 and fixed to the pusher plate 15. The screw shaft 17 screwed to the nut 16 and the rear plate 12 are fixed to the screw shaft 17 via the transmission mechanism 18. An injection electric servomotor (injection shaft servomotor) 19 that rotates to move the injection screw 14 in the axial direction, and a screw that is fixed to the pusher plate 15 and rotates the injection screw 14 via a transmission mechanism 20. An electric servomotor for rotation (servo motor for screw shaft) 21 is provided.
[0013]
The screw shaft 17 and the nut 16 constitute a screw mechanism 22 that converts the rotational motion of the injection shaft servomotor 19 into a linear motion and moves the pusher plate 15 in the axial direction of the injection screw 14.
Then, by rotating the screw shaft servo motor 21, the resin material introduced into the heating cylinder 13 from the hopper 13 a provided at the base end of the heating cylinder 13 is plasticized, and the distal end of the heating cylinder 13 is plasticized. The molten resin is supplied to the resin reservoir 13b and weighed, and by rotating the servo motor 19 for the injection shaft, the pusher plate 15 is moved via the screw mechanism 22, and the resin reservoir 13b is metered. Back pressure is applied via the injection screw 14 that moves backward with respect to the molten resin, and the measured molten resin moves from the injection nozzle 13 c of the heating cylinder 13 to the molding cavity of the mold K by the forward movement of the injection screw 14. A is injected.
The injection shaft servomotor 19 is provided with an encoder (screw position detector) 19a, the screw shaft servomotor 21 is provided with an encoder (screw rotation speed detector) 21a, and a pusher The plate 15 is provided with a load cell 15 a for detecting a pressing force (load) acting on the injection screw 14.
[0014]
In FIG. 1, reference numeral 23 denotes a control device that controls the electric injection molding machine 1. The control device 23 includes a controller 24 that controls the overall operation of the electric injection molding machine 1, various operation switches 25 a, a machine operation panel 25 that inputs various instruction items to the controller 24, and a controller 24. A display 26 for inputting various data output from the controller and various setting numerical values, and a servo amplifier, and operates based on an operation command from the controller 24 to operate the injection shaft servo motor 19. In addition, the controller 24 includes an injection shaft control drive device 27 that supplies a screw position signal p detected by the encoder 19a and a load signal k detected by the load cell 15a to the controller 24, and a servo amplifier. The screw shaft servomotor 21 is operated by operating based on the operation command from Wherein and a screw rotational speed signal f which is detected by the encoder 21a and a screw shaft for controlling the driving device 28 supplies to the controller 24.
[0015]
The injection shaft control drive unit 27 rotates the rotation amount (rotation position) of the injection shaft servomotor 19 based on the screw position signal p detected by the encoder 19a and the load signal k detected by the load cell 15a. And the rotational force (driving torque), that is, the forward / backward movement position of the injection screw 14, the injection speed, the injection pressure, and the back pressure are feedback-controlled. The screw shaft control drive unit 28 feedback-controls the rotational speed of the screw shaft servomotor 21, that is, the rotational speed of the injection screw 14, based on the screw rotational speed signal f detected by the encoder 21a. It is like that.
[0016]
The indicator 26 comprises a touch panel type indicator, a speed setter 26a for setting the forward / backward moving speed of the injection screw 14, and a pressure setter 26b for setting an injection pressure and a back pressure acting on the injection screw 14. And the most advanced end position (injection completion position) Pe from which the filling of the molten resin into the mold K is completed from the backward end position (measurement completion position) Po (see FIG. 4) at the completion of the measurement of the molten resin of the injection screw 14. In the injection stroke Lo up to, the forward end positions (target positions) P1, P2,... Pn (see FIG. 4) when the injection screw 14 repeatedly advances, and the injection speed of the injection screw 14 is changed. An injection position setting device 26c for setting the position, a number setting device 26d for setting the number n of times that the injection screw 14 repeats forward movement, and a time for setting the rotation speed of the injection screw 14. The speed setting unit 26e, the time setting unit 26f for setting the rotation operation time t of the injection screw 14 and the pressure holding process time T, the supply operation by the rotation of the injection screw 14 and the injection operation by the advancement of the injection screw 14 are repeated a plurality of times. A changeover switch 26g for selecting whether or not to perform molding according to a specific molding operation mode to be performed and other setting devices are provided.
[0017]
The controller 24 is a sequence program for controlling the overall operation of the electric injection molding machine 1, set values set by the setting devices 26a, 26b, 26c, 26d, 26e, and 26f in the display 26, etc. A memory 24a for storing the molding conditions of the injection molding machine 1) and a timer function (timer means) 24b, and based on setting values stored in the memory 24a and detection values of the load cell 15a and encoders 19a and 21a. Then, various control data for operating the electric injection molding machine 1 by performing required arithmetic processing and the like are generated, and the control data is output to the injection shaft control drive device 27 and the screw shaft control drive device 28. And a control unit 24c for outputting a required display item to the display 26.
[0018]
Next, an injection molding method by the electric injection molding machine 1 having the above configuration will be described with reference to FIGS.
Prior to starting the molding operation by the electric injection molding machine 1, the shape of the molded product (mold cavity A) to be molded is examined, and the injection screw 14 moves to the resin reservoir 13 b in the heating cylinder 13. The most advanced end position Pe, which is advanced from the measurement completion position which has been retracted by the measurement of the molten resin and the filling of the molten resin mold K is completed (in the actual molding operation, the molten resin is slightly left in the heating cylinder 13 and injected. Since the operation is terminated, the most forward end position Pe is a position before the most forward end position where the injection screw 14 can be moved forward in the heating cylinder 13). Corresponding to the section in which molding is performed according to the specific molding operation mode, for example, the thin portion of the molded product, the portion where the surface is important, the various regions filled with the molten resin such as other portions, etc. Each forward end position when Ryu 14 repeats a plurality of times forward P1, P2, previously determined · · · Pn and the number of repetitions n.
[0019]
Then, it is selected in advance whether or not the molding according to the specific molding operation mode is performed by the changeover switch 26g of the display 26. Further, the forward end positions P1, P2,... Pn of the injection screw 14 and the number of times of repeating the forward movement n are respectively input and set in the position setting device 26c and the number setting device 26d of the display 26, and Predetermined numerical values are set and input to the speed setter 26a, the pressure setter 26b, the rotational speed setter 26e, and the time setter 26f, respectively. These setting and input numerical values are stored in the memory 24a via the control unit 24c of the controller 24, and the selected required items are displayed on the display 26. Thereafter, the operation switch 25a of the machine operation panel 25 is operated to start the molding operation by the electric injection molding machine 1.
[0020]
When the molding operation is started, the molding operation is executed in accordance with a sequence program stored in the memory 24a of the controller 24 of the control device 23, and the screw shaft control drive device 28 and the injection shaft control are controlled by a command from the controller 24. The screw shaft servomotor 21 and the injection shaft servomotor 19 are rotated via the drive device 27, respectively, and the injection screw 14 and the screw shaft 17 are rotated via the transmission mechanisms 20 and 18, respectively. By the rotation of the injection screw 14, the resin material introduced into the heating cylinder 13 from the hopper 13a is plasticized and melted, and a supply operation for supplying the resin material to the resin reservoir 13b of the heating cylinder 13 is performed. At this time, a pressing force is applied to the injection screw 14 that is pressed by the molten resin supplied to the resin reservoir 13b and moved backward by the pusher plate 15 that is moved through the screw mechanism 22 by the rotation of the screw shaft 17. As a result, a predetermined back pressure set by the pressure setting device 26b is applied to the molten resin in the resin reservoir 13b.
[0021]
When it is confirmed by the encoder 19a that the injection screw 14 has reached the measurement completion position Po at its backward end and the measurement of the molten resin has been completed, as shown in FIG. The injection screw 14 is moved forward by the rotation of the shaft servomotor 19, and an injection operation is performed to fill the molding resin A of the mold K with the molten resin measured in the resin reservoir 13b (step S1). When the injection screw 14 moves forward by the injection operation and reaches the first forward end position (first target position) P1 set by the position setting device 26c (step S2), the injection by the injection shaft servomotor 19 is performed. After the pressure of the screw 14 in the axial direction is released to reduce the resin pressure of the molten resin in the resin reservoir 13b (step S3), the molding according to the specific molding operation mode is performed. Is determined from the switching state of the selector switch 26g of the indicator 26 (step S4), and when the molding according to the specific molding operation mode is not performed, the first target position P1 is the final forward end position ( In the state where a predetermined back pressure is applied to the molten resin in the resin reservoir 13b by the rotation of the injection shaft servomotor 19, it is regarded as the final target position Pn. The supply operation is performed 14 is rotated (step S5). By this supply operation, the molten resin plasticized in the heating cylinder 13 is filled into the molding cavity A of the mold K through the resin reservoir 13b.
[0022]
Whether or not the supply operation has been performed for the last set time tn set in the time setting device 26f is determined by the time measurement of the clock function 24b of the control unit 24c (step S6), and the supply operation is performed for the set time tn. If not, it is judged whether or not the injection screw 14 has been moved backward by the resin pressure to the screw backward position Pna set by the position setting device 26c (step S7), and the backward movement to the screw backward position Pna is made. When not, the supply operation is continued after returning to step S5. As a result, the supply operation by the rotation of the injection screw 14 is stopped and the injection operation is immediately performed when the earlier one of the conditions in which the supply operation reaches the set time tn or the screw retracted position Pna, whichever is earlier, is satisfied. The shaft servomotor 19 is rotated and the injection screw 14 is moved forward at the end of the set time tn or from the screw retracted position Pna to the most advanced position Pe, and into the molten resin mold K in the resin reservoir 13b. Final injection (normal injection operation) is performed at the set injection speed and set injection pressure, and the subsequent normal holding pressure (holding pressure operation) is set based on the multi-stage setting pressure. (Step S8).
After the pressure holding operation is completed, the pressure release operation of the injection screw 14 is performed as in step S3 (step S9), and the measurement is performed by the molten resin supply operation to the resin reservoir 13b of the heating cylinder 13. (Step S10), preparations for starting the next molding cycle are made, and one cycle of the injection molding operation is completed.
[0023]
After the final injection and holding pressure, without performing the depressurization operation in the step S9, the measurement by the supplying operation in the step S10 is started immediately in the final stage of the holding pressure. The back pressure applied to the molten resin in the resin reservoir 13b of the heating cylinder 13 by pressing the injection screw 14 in the forward direction is set to be higher than the pressure in the final stage, so that the molten resin in the next molding cycle is measured. The pressure can also be used as the final pressure of the molten resin previously filled in the mold K, and the molding cycle time can be shortened. It is effective when molding.
[0024]
In the step S4, when the molding according to the specific molding operation mode is performed, the process proceeds to a step S11, and similarly to the operations in the steps S5 to S7, the resin reservoir 13b is rotated by the rotation of the injection shaft servomotor 19. With the back pressure applied to the molten resin, the injection screw 14 is rotated and the supply operation is performed to fill the mold K with the molten resin (step S11). Then, whether or not the supply operation has been performed only for the first set time t1 set in the time setting device 26f is determined by the time measurement of the clock function 24b of the control unit 24c (step S12), and the supply operation is performed. When the first set time t1 is not performed, it is determined whether or not the injection screw 14 has moved backward to the first screw retract position P1a set by the position setter 26c (step S13). When the screw does not move back to the screw retracted position P1a, the process returns to step S11 and the supply operation is continued, so that the supply operation reaches the first set time t1 or the first screw retracted position P1a. When the earlier condition is satisfied, the number of repetitions of the forward operation (the injection operation) of the injection screw 14 is the number of times setting device 26d. Whether the host vehicle has reached it is determined to set the repeat count n (step S14).
[0025]
In step S14, if the number of repetitions of the forward movement of the injection screw 14 has reached the number of repetitions n set in the number setting device 26d, the injection screw 14 is advanced by the rotation of the injection shaft servomotor 19, and the An injection operation for filling the mold K with the molten resin in the resin reservoir 13b is performed (step S15), and the injection screw 14 advanced by this injection operation is the final advance end set in the position setting device 26c. It is determined whether or not the position (final target position) Pn has been reached (step S16). When the position has not been reached, the injection operation is continued, and when it has reached, that is, until the final target position Pn is reached. After the operation is performed, the pressing force in the axial direction of the injection screw 14 by the injection shaft servomotor 19 is the same as in step S3. Released to the taking place is depressurized to lower the resin pressure of the molten resin within the resin reservoir 13b (step S17), the operation up to the step S10 returns to the step S5 is performed.
[0026]
When the number of repetitions of the forward movement of the injection screw 14 in step 14 has not reached the number of repetitions n set in the number setting device 26d, the injection screw 14 is moved forward to remove the molten resin in the resin reservoir 13b. An injection operation for filling the mold K is performed (step S18). By this injection operation, it is determined whether or not the injection screw 14 has reached the second (next) forward end position (second target position) P2 set in the position setting device 26c (step S19). If not, the injection operation is continued. When the injection operation is reached, that is, after the injection operation is continued until the injection screw 14 reaches the second target position P2, the same as in steps S3, S9, and S17. After a proper pressure release operation is performed (step S20), the process returns to step S11. The operations from step S11 to step S20 are repeated until the number of repetitions of the forward movement of the injection screw 14 reaches the number n set in the number setting unit 26d.
In the above, the rotational speed of the injection screw 14 that operates in the supply operation, the screw retracted positions P1a, P2a,... Pna, the screw rotation times t1, t2,. Thus, it can be determined appropriately based on experience, or can be set appropriately so that a high-quality molded product can be obtained by trial of a molding operation.
[0027]
According to the injection molding method in the injection molding machine, the molten resin is supplied to the resin reservoir 13b at the tip of the heating cylinder 13 of the injection device 3 and weighed. In the injection process of filling the molding cavity A of the mold K, the injection screw 14 is advanced to each advance end position (each target position) P1, P2,... Pn within the injection stroke Lo of the injection screw 14 and heated. The injection operation of filling the mold K with the molten resin in the resin reservoir 13b of the cylinder 13 and the injection screw 14 is rotated with the back pressure applied to the injection screw 14 to melt into the resin reservoir 13b of the heating cylinder 13. After repeating the supply operation of filling the mold K while supplying the resin a plurality of times, the injection screw 14 is advanced to the most forward end position Pe in the injection stroke Lo. Since the pressure-holding operation in the pressure-holding process is performed after the final injection operation, the section within the injection stroke Lo that requires relatively high-speed filling corresponding to the thin-walled part of the molded product, the part where the surface is important, etc. Then, the molten resin is filled into the mold K by the injection operation, and the molten resin is filled into the mold K by the supply operation in the section within the injection stroke Lo corresponding to the thick part and the other parts. It can be molded while supplementing, and it is possible to reliably obtain a molded product with a good appearance, and even a molded product with a capacity exceeding the injection capacity specification of the injection molding machine is efficient and easy. The molding cycle time can be shortened.
[0028]
The supply operation of filling the mold K while supplying the molten resin to the resin reservoir 13b of the heating cylinder 13 by the rotation of the injection screw 14 is performed by the injection screw 14 at each target position P1, P2,. Starts when moving forward to Pn and ends when each set time t1, t2,... Tn elapses or when the injection screw 14 moves back to each screw retracted position P1a, P2a,. Since the injection operation by the advance of the injection screw 14 is started at the same time, the injection operation and the supply operation are accurately repeated corresponding to a plurality of target positions P1, P2,... Pn in the injection stroke Lo. The molten resin can be filled faithfully into the molding cavity A of the mold K.
[0029]
  Further, in the pressure-holding step after the final injection, the pressure-holding pressure can be arbitrarily set in a plurality of stages, but in a state where back pressure is applied to the injection screw 14 at a pressure higher than the pressure-holding pressure at the final stage.Metering operation of molten resin to resin reservoir 13b of heating cylinder 13When the measurement of the molten resin by the rotation of the injection screw 14 into the resin reservoir portion 13b of the heating cylinder 13 is started, the back pressure against the molten resin at the time of measurement in the next molding cycle is first applied to the mold K. This can also serve as the final pressure holding of the molten resin filled in the resin, and the molding cycle time can be further shortened.
  In the above, the position setter 26e is set so that the target positions P1, P2,... Pn at the time of the injection operation by the injection screw 14 are advanced to the advance side of the injection stroke Lo in the order of repetition of the injection operation. As an exampleexplained.
[0030]
In the embodiment, the injection screw 14 inserted into the heating cylinder 13 is linearly moved through the screw mechanism 22 in which the rotation of the injection shaft servo motor 19 is screwed onto the screw shaft 17 and the nut 16 is screwed. The electric injection molding machine 1 according to the present invention is adapted to control the operation of the injection screw 14 by detecting the moving position of the injection screw 14 by the encoder 19a of the injection shaft servomotor 19 by converting the position and moving forward and backward. Although the present invention is not limited to this example, the present invention is not limited to this. The injection screw 14 is moved forward and backward by a hydraulic cylinder, and the movement position of the injection screw 14 is directly detected by a position sensor. It can also be implemented in a hydraulic injection molding machine that controls the above.
[0031]
Moreover, although the said embodiment is an example in the case of implementing the injection molding method of this invention in an in-line screw type injection molding machine, this invention is not restricted to this, A filling plunger (injection member) in a filling cylinder Is equipped with a filling device inserted in a freely moving forward and backward direction and a plasticizing device in which a plasticizing screw is rotatably inserted into a plasticizing heating cylinder, and the plasticizing screw of the plasticizing device is rotated to plasticize the resin material. A pre-plastic type in which molten resin is supplied to the resin reservoir at the tip of the filling cylinder, the molten resin is measured in the filling cylinder, and the measured molten resin is filled into the mold by the advance of the filling plunger. You may make it implement in an injection molding machine.
[0032]
【The invention's effect】
  As described above, according to the present invention, the following excellent effects are obtained.
  According to the injection molding method in the injection molding machine according to claim 1, in the injection process by the injection device, the injection operation to the mold of the molten resin by advance to the target position within the injection stroke of the injection member;From the target position to the retracted position of the injection memberThe supply operation of filling the mold while supplying molten resin to the tip of the heating cylinder with back pressure applied to the injection member is repeated several times.And thenThe pressure holding operation in the pressure holding process is performed after the final injection operation by the advance of the injection member.The plurality of target positions and the retreat positions are positions that are gradually advanced toward the injection completion position that completes the filling of the mold, and the retreat positions are the measurement completion positions rather than the immediately preceding target positions. Is the position retracted to the sideAs a result, the molten resin is filled by the injection operation in the injection stroke section that requires relatively high-speed filling, such as the thin-walled part of the molded product, the part where the surface is important, etc. In the section of the injection stroke corresponding to this part, it is possible to mold while filling the molten resin into the mold by supplying operation and supplementing the injection amount, and it is possible to reliably obtain a molded product with a good appearance, Even a molded product having a capacity exceeding the injection capacity specification of the injection molding machine can be efficiently and easily molded, and the molding cycle time can be shortened.
[0033]
  According to the injection molding method in the injection molding machine according to claim 2, the supply operation is started when the injection member moves forward to the target position, and the set time has elapsed or the injection member has moved back by the set distance.Of the retracted positionEnds at the same time as the supply operation endsNext injectionSince the operation is started, the injection operation and the supply operation are accurately repeated according to the stroke divided into a plurality of injection strokes of the injection member, and the molten resin is faithfully applied to the molding cavity of the mold. Can be filled.
[0034]
  According to the injection molding method in the injection molding machine according to claim 3, the pressure holding work.After the final stageBack pressure is applied to the injection member at a pressure higher than the holding pressure ofHeated withSince the measurement of the molten resin into the cylinder is started, the back pressure against the molten resin at the time of measurement in the next molding cycle may also serve as the final pressure holding of the molten resin previously filled in the mold. This can further reduce the molding cycle time.
[0035]
According to the injection molding method in the injection molding machine according to claim 4, the injection molding machine has an injection screw as an injection member inserted in the heating cylinder so as to be movable in the axial direction of the heating cylinder and rotatable in the circumferential direction. Inline screw type injection molding machine, and the supply operation is performed by plasticizing the resin introduced to the base end side of the heating cylinder by the rotation of the injection screw. An injection molding method for obtaining a high-quality molded product by repeating the supply operation a plurality of times can be easily realized in an in-line screw type injection molding machine.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an example of an injection molding machine that performs an injection molding method in an injection molding machine according to the present invention.
FIG. 2 is a flowchart illustrating the operation in the same manner.
FIG. 3 is a flow diagram for explaining the main part of the operation.
FIG. 4 is an explanatory view showing an embodiment of an injection molding method in an injection molding machine according to the present invention.
[Explanation of symbols]
1 Electric injection molding machine
3 Injection device
13 Heating cylinder
13b Resin reservoir
14 Injection screw (injection member)
19 Electric servo motor for injection (servo motor for injection shaft)
19a Encoder (screw position detector)
21 Electric servo motor for screw rotation (servo motor for screw shaft)
21a Encoder (Rotation speed detector)
23 Control device
24 controller
24a memory
24b Clock function (time measuring means)
26 Display
26a Speed setting device
26c Position setter
26d Division number setter
26e Rotation speed setter
26f Time setter
26g selector switch
27 Control drive for injection shaft
28 Screw shaft control drive
A Molding cavity
K mold
P1, P2, Pn Each forward end position (each target position) of injection screw
Pe Most advanced position of injection screw (injection completion position)

Claims (4)

In an injection molding method in an injection molding machine for supplying a molten resin to a tip portion in a heating cylinder of an injection device and measuring the molten resin, and injecting the measured molten resin into a mold by an injection member,
In the injection step, the injection operation to the mold of the molten resin by advance to the target position within the injection stroke of the injection member,
Just repeat a plurality of times and supplying operation of filling the mold while supplying molten resin to the tip of the heating cylinder while adding back pressure in an injection member to the retracted position of the exit member from the target position,
After that, the pressure holding operation in the pressure holding process is performed through the final injection operation by the advance of the injection member ,
The plurality of target positions and retreat positions are positions that are gradually advanced toward the injection completion position where the filling of the mold is completed, and the retreat position is retreated closer to the measurement completion position than the previous target position. injection molding process in an injection molding machine, characterized in that the a position. Wherein the feed operation was started when the injection member is advanced to the target location, and set time has elapsed or injection member is terminated at the retracted position by retracting the set distance, the next injection process at the same time to end the supply operation injection molding process in an injection molding machine according to claim 1, characterized by starting the. 3. The measurement of the molten resin into the heating cylinder is started after the pressure-holding step, with a back pressure applied to the injection member at a pressure higher than the pressure at the final stage. Injection molding method in an injection molding machine.   The injection molding machine comprises an in-line screw type injection molding machine in which an injection screw as an injection member is inserted in the heating cylinder so as to be movable in the axial direction of the heating cylinder and to be rotatable in the circumferential direction. The injection molding method for an injection molding machine according to any one of claims 1 to 3, wherein the resin introduced into the base end side of the heating cylinder is plasticized by rotation of the injection screw.

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