WO2015178388A1

WO2015178388A1 - Injection molding device and operation control method for same

Info

Publication number: WO2015178388A1
Application number: PCT/JP2015/064364
Authority: WO
Inventors: 博子田中; 井上　玲
Original assignee: 東洋機械金属株式会社
Priority date: 2014-05-21
Filing date: 2015-05-19
Publication date: 2015-11-26
Also published as: CN106457640B; CN106457640A; JP6438215B2; JP2015217666A

Abstract

Provided are: an injection molding device that can reliably prevent the occurrence of the stringing phenomenon without using a special device and without extending a molding cycle time; and an operation control method for the injection molding device. After an injection step (a primary injection step and a subsequent dwelling step) ends and a cooling step is started, pressure is applied to the resin inside an injection nozzle by moving a screw (s) forward, and the occurrence of the stringing phenomenon is prevented.

Description

Injection molding machine and operation control method thereof

The present invention relates to an injection molding machine and an operation control method thereof, and more particularly, to an operation control method of an injection molding machine for preventing resin stringing.

As shown in FIG. 7, in the injection molding machine equipped with a cold runner mold, the inlet portion of the sprue 102 formed in the fixed side mold 101 and the resin injection hole 104 formed in the injection nozzle 103 are always in communication. is doing. For this reason, when the movable side mold (not shown) is opened and the molded product P is taken out from the cavity 105, a stringing phenomenon occurs between the molded product P and the molten resin in the resin injection hole 104, and the thread-like resin T is removed. Prone to occur. When the filamentous resin T is generated due to the stringing phenomenon, it remains in the fixed side mold 101 when the molded product P is taken out, causing a molding defect in the molded product P in the next cycle, or the fixed side mold 101 and the movable side mold 101. There is a risk that the mold apparatus will be damaged by being sandwiched between the parting surfaces of the mold. In addition, the code | symbol S in a figure has shown the screw which plasticizes raw material resin and injects molten resin.

The stringing phenomenon is caused by a high resin temperature in the resin injection hole 104 when the molded product P is taken out. Therefore, in order to prevent the stringing phenomenon from occurring, the tip of the injection nozzle 103 is efficiently cooled. There is a need to. Conventionally, from such a point of view, measures such as extending the cooling time of the molded product P and the sprue 102 by moving the mounting position of a heater (not shown) that heats the injection nozzle 103 away from the tip of the injection nozzle 103 (for example, patents) (Refer to the Background Art section of Document 1), and measures such as limiting energization to the heater that is heating the injection nozzle 103, and installing a needle valve in the resin injection hole 104 to prevent resin leakage. (For example, refer to the background art section of Patent Document 2).

In addition, depending on these measures, in view of the fact that it is actually difficult to prevent the occurrence of the stringing phenomenon without reducing the production efficiency of the molded product P, the occurrence of the stringing phenomenon itself is not prevented. In addition, a technique for treating the thread-like resin T so that the thread-like resin T generated by the stringing phenomenon does not cause molding defects or damage to the mold has been proposed (for example, abstracts of Patent Documents 1 and 2). See). The technique described in Patent Document 1 is for sucking the filamentous resin T generated by the stringing phenomenon using a suction device until the take-out machine discharges the sprue. In addition, the technique described in Patent Document 2 is such that after the cooling step is finished, the movable mold is once opened to an arbitrary position and then closed again to an arbitrary position, thereby causing a thread-like resin generated by a stringing phenomenon. T is brought into contact with the molten resin stored in the injection nozzle 103 and remelted.

JP 2007-196518 A JP-A-6-170901

However, since the technique described in Patent Document 1 must be provided with a suction device separately, the configuration of the injection molding machine becomes complicated and the injection molding machine becomes expensive. In addition, the technique described in Patent Document 2 makes it difficult to reliably re-contact the filamentous resin T generated by the stringing phenomenon with the molten resin stored in the injection nozzle 103, and increases the molding cycle. There is a problem that the manufacturing efficiency of the molded product is deteriorated.

The present invention has been made in view of the situation of the prior art as described above, and its purpose is to ensure the occurrence of the yarn pulling phenomenon without using a special device and without extending the molding cycle time. An object of the present invention is to provide an injection molding machine that can be prevented and an operation control method thereof.

In order to solve the above problems, the present invention relates to an injection molding machine, and includes an injection condition setting unit including a display unit and an input unit, and a control unit that controls drive control of the entire injection molding machine. In the molding machine, the molding condition setting unit is configured to be able to set a pre-plasticizing pressure condition as a molding condition setting item, and an operator operates the input unit to press the pre-plasticizing pressure. When the conditions are set, the control unit, after the molding cycle shifts from the injection process to the cooling process, before the plasticizing process starts, the pre-plasticizing pressure condition set in the molding condition setting unit. In accordance with the above, control is performed to pressurize the resin in the injection nozzle, and after the completion of the control, the process proceeds to a plasticizing step.

When the molding cycle enters the cooling process, the molded product is cooled, so the heat of the resin present at the sprue inlet moves to the mold side. Also, since the tip of the injection nozzle is in contact with the mold, it is cooled by the mold, and the heat of the resin present in the resin injection hole of the injection nozzle moves to the mold side through the injection nozzle. To do. In this state, when the resin in the injection nozzle is pressurized, the adhesion between the resin at the sprue inlet and the mold and the adhesion between the resin in the resin injection hole and the injection nozzle are increased. Since the thermal resistance at the interface is reduced, the heat of the resin in the resin injection holes can easily escape to the mold side. As a result, the resin temperature in the resin injection hole is quickly lowered and the resin viscosity of the portion is increased, so that the occurrence of the stringing phenomenon can be reliably prevented. In addition, since no special mechanism or equipment for preventing the yarn pulling phenomenon is required, an injection molding machine that does not cause the yarn pulling phenomenon can be implemented at low cost.

In the injection molding machine having the above-described configuration, the molding condition setting unit can select whether or not to set the pre-plasticizing pressurization condition. In this case, the molding cycle time is kept constant both when the setting of the pre-plasticizing pressure condition is selected and when the pre-plasticizing pressure condition is not set.

Depending on molding conditions, pressurizing operation before plasticization may not be required. For this reason, by configuring the molding condition setting unit so that it is possible to select whether or not to set the pre-plasticizing pressurizing condition, the molding condition setting work when the pre-plasticizing pressurizing operation is not required. Complexity can be avoided, and the molding condition setting work can be made more efficient. In addition, regardless of whether or not the pre-plasticizing pressure condition is set, high molding product manufacturing efficiency can be maintained by keeping the molding cycle time of the injection molding machine constant.

Further, the present invention is characterized in that in the injection molding machine configured as described above, the molding condition setting unit sets a resin pressure and a pressurizing time in the injection nozzle as pressurizing conditions before plasticization.

As described above, when the resin in the injection nozzle is pressurized in the cooling step, the heat dissipation efficiency of the resin in the resin injection hole can be increased, and the occurrence of the stringing phenomenon can be prevented. This effect increases as the pressure is increased and the pressurization time is increased. However, if the resin temperature in the resin injection hole becomes too low, the resin in the resin injection hole in the next cycle may be hardened and may not be injected. If the resin pressure in the injection nozzle and the pressurization time can be set as the pre-plasticization pressurization conditions, the pre-plasticization pressurization conditions can be appropriately set within a range that does not cause such inconvenience. It is possible to achieve both the prevention of the phenomenon and the prevention of the extension of the molding cycle.

Further, in the injection molding machine having the above-described configuration, the display unit displays a selection button as to whether or not to set the pre-plasticizing pressure condition, and the operator operates the input unit, When the selection button for setting the pre-plasticizing pressurizing condition is selected, the pre-plasticizing pressurizing condition setting screen is displayed in the screen displaying the select button.

According to such a configuration, the selection button for setting the pre-plasticizing pressure condition and the setting screen for the pre-plasticizing pressure condition are displayed on the same screen. It can be done easily.

On the other hand, the present invention relates to an operation control method for an injection molding machine, and repeats a molding cycle including a plasticizing step, an injection step, a pressure holding step, a cooling step, a plasticizing step of the next cycle, and a molded product taking out step. In an operation control method for an injection molding machine for continuously producing a molded product, after the pressure-holding step is finished and the cooling step is started, before the plasticizing step of the next cycle is started, the inside of the injection nozzle A pressurization operation before plasticization for increasing the resin pressure is performed, and after the pre-plasticization pressurization operation, the process proceeds to the plasticization step of the next cycle.

In the cooling process, since the molded product is cooled, it is easy to increase the viscosity of the resin present in the resin injection holes. On the other hand, in the plasticizing step, the heating cylinder including the injection nozzle is heated to plasticize the raw material resin, so that it is difficult to increase the viscosity of the resin present in the resin injection hole. Therefore, by performing the pre-plasticizing pressurization operation after the start of the cooling step and before the start of the plasticizing step of the next cycle, the occurrence of stringing can be easily and reliably prevented.

According to the present invention, it is possible to prevent the stringing phenomenon from occurring by simply increasing the resin pressure in the injection nozzle after the start of the cooling process. Is possible. In addition, after the start of the cooling process and before the plasticization process of the next cycle, the pre-plasticizing pressurization operation is performed, so that the molding cycle is not lengthened and is equivalent to the case where the pre-plasticization pressurization operation is not performed The manufacturing efficiency of the molded product can be maintained.

It is a block diagram of the injection molding machine which concerns on embodiment. It is a figure which shows the molding cycle of the injection molding machine which concerns on embodiment compared with the molding cycle of the injection molding machine which concerns on a prior art example. It is a block diagram of the menu screen displayed on a display part. It is a block diagram of the injection | emission / plasticization screen displayed on a display part. It is a figure which shows the effect of the injection molding machine which concerns on embodiment. It is explanatory drawing of the stringing phenomenon which appears in an injection molding machine.

Hereinafter, an embodiment of an injection molding machine according to the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of an injection molding machine according to the embodiment. The injection molding machine 1 of this example includes a molding mechanism unit 10 that molds a molded product by a mechanical operation, a microcomputer unit (control unit) 20 that controls driving of the molding mechanism unit 10, and an output interface for an operator. A display unit 30, an input unit 40 that is an input interface for receiving an input from an operator, and an input / output terminal unit 50 for connecting an external memory 70 are provided. In addition, it can replace with the structure provided with the display part 30 and the input part 40 separately, and can also be set as the structure provided with the touchscreen with which the display part 30 and the input part 40 were combined together.

The molding mechanism unit 10 is mainly composed of an injection unit 11 and a mold clamping unit 12. The mold clamping unit 12 performs an opening / closing operation of the mold 13, and the injection unit 11 injects a molding material into a cavity formed in the mold 13. Each of these

units

11 and 12 is provided with a plurality of electric servo motors 14 as a power source of the movable part, and each electric servo motor 14 is provided with an encoder 15 for detecting the rotational position thereof. Yes. Each electric servo motor 14 is feedback-controlled by a control signal output from the microcomputer unit 20.

In the microcomputer unit 20, each drive unit input / output unit 21 that takes in an output signal from the encoder 15 and outputs a control signal to the electric servomotor 14, and each drive unit control that performs drive control of the electric servomotor 14. Discrimination of signals from the input unit 40, the storage unit 23 for storing the molding conditions, the control unit 24 for controlling the entire apparatus, the display processing unit 25 for controlling the display unit 30, etc. And an external memory input / output processing unit 27 for processing signals input / output from the input / output terminal unit 50.

The injection molding machine according to the embodiment can automatically execute the pre-plasticization pressurization operation during the automatic operation by setting the pre-plasticization pressurization conditions on the setting screen displayed on the display unit 30. It has become.

As shown in FIG. 2, the pre-plasticizing pressurization operation is the injection nozzle 103 (see FIG. 6) after the injection process (primary injection process and subsequent pressure holding process) is completed and the cooling process is started. This is an operation control in which the resin inside is pressurized by advancing the screw S (see FIG. 6) to prevent the yarn pulling phenomenon. In the conventional injection molding machine, as shown in comparison with FIG. 2, the injection process is completed and the cooling process is started, and at the same time, the plasticizing process is performed, and the pre-plasticizing pressure operation is not performed. The reason why the stringing phenomenon is prevented by pressurizing the resin in the injection nozzle 103 is that, as described above, the heat dissipation efficiency of the resin in the resin injection hole 104 (see FIG. 6) is increased by the pressurization. . The stringing prevention effect increases as the resin pressure during the pre-plasticizing pressurization operation increases and as the pre-plasticization pressurization operation time increases, but on the other hand, the resin in the resin injection holes tends to solidify. Therefore, it may take a long time for remelting, or the resin in the injection nozzle may deteriorate and adversely affect the quality of the molded product. Set pressure and pressurization time. According to the experiment, although depending on the resin material and the size of the injection nozzle, good results were obtained by setting the resin pressure to 30 MPa to 60 MPa and the pressurization time to about 1 second.

Hereinafter, a method for setting pre-plasticizing pressure conditions in the injection molding machine according to the embodiment will be described. In the following description, a method for setting the pre-plasticizing pressure condition in the manual setting mode will be described. However, the pre-plasticizing pressure condition can be set in the same manner in the automatic setting mode.

When the microcomputer 20 is activated, a menu screen 61 shown in FIG. In this example, the menu screen 61 includes “injection / plasticization”, “mold opening / closing / EJ (abbreviation of EJECT; product removal)”, “temperature setting”, “production management”, “graph”, “monitor”, It is divided into 10 items of “setup”, “inspection”, “option operation”, and “system setting”, and 2 to 5 selection buttons are provided for each item.

In this state, when the operator selects “Injection / Plastification” from the “Injection / Plastification” menu, an injection / plasticization screen 62 shown in FIG. On the lower left of 62, an ON / OFF button 63 for selecting whether or not to perform pressure setting before plasticization is displayed. The ON / OFF button 63 is alternately switched between ON and OFF every time the operator operates the input unit 40 to operate the button. When the operator operates the ON / OFF button 63 to select ON (perform pressure setting before plasticization), as shown in FIG. A setting field 64 appears. In the pre-plasticization pressurization condition setting field 64, a resin pressure setting field 65 and a pressurization time setting field 66 are displayed. The operator operates the input unit 40 to complete the input to the resin pressure setting field 65 and the pressurization time setting field 66, and operates the X button on the upper right, thereby allowing the pre-plasticization addition from the injection / plasticization screen 62. The pressure condition setting field 64 disappears and molding conditions can be set in other setting fields on the injection / plasticization screen 62.

As described above, the injection molding machine according to the embodiment includes an ON / OFF button 63 for selecting whether or not to perform pre-plasticization pressurization setting in the injection / plasticization screen 62, and pre-plasticization pressurization. Since the condition setting column 64 is displayed, it is possible to easily perform the setting operation of the pre-plasticizing pressure condition. Of course, the ON / OFF button 63 and the pre-plasticizing pressurizing condition setting field 64 can be displayed on a screen other than the injection / plasticizing screen 62. Further, the display positions of the ON / OFF button 63 and the pre-plasticizing pressure condition setting field 64 in the screen can be freely changed regardless of the description in FIG.

After setting the pre-plasticizing pressurization conditions, when the operator operates the input unit 40 to select the start of continuous automatic operation, as shown in FIG. 2, the plasticizing process after the molding cycle enters the cooling process Before the start of the pressure, the pre-plasticizing pressurization operation is performed, and the resin pressure set in the resin pressure setting column 65 is added to the resin existing in the injection nozzle 103 for the time set in the pressurization time setting column 66. . As a result, the heat of the resin staying in the resin injection hole 104 is quickly radiated to the mold 101 (see FIG. 5) side, and the resin temperature of the portion is lowered, thereby preventing or suppressing the occurrence of the stringing phenomenon. can do. FIG. 5 shows the state of the molded product P when the pre-plasticizing pressurization operation is performed. As is apparent from the comparison with FIG. 6, even if the stringing phenomenon occurs, the molded product P is formed. The length of the filamentous fiber T is much shorter. Therefore, the presence of the filamentous fiber T does not cause molding defects or damage to the mold, and the injection molding machine can be operated with high efficiency.

As shown in FIG. 2, the microcomputer 20 pressurizes before plasticization so that the molding cycle time is constant regardless of whether the operator selects the pre-plasticizing pressurization operation or not. Controls the drive of the injection molding machine after operation. In the pre-plasticizing pressurization operation, the resin pressure is about 30 MPa to 60 MPa and the pressurization time is about 1 second. Therefore, even if this operation is performed, the thermal influence is negligible in the whole injection molding machine. For this reason, the microcomputer 20 can perform control during continuous automatic operation without extending the molding cycle time. As described above, the injection molding machine according to the embodiment can maintain the same molded product manufacturing efficiency as the case where the operation is not performed even when the pre-plasticizing pressurization operation is performed.

The injection molding machine according to the embodiment can prevent the yarn pulling phenomenon only by applying a pre-plasticizing pressurization operation during the molding cycle, and does not require a special mechanism or equipment, so that the yarn pulling phenomenon does not occur. A molding machine can be implemented at low cost.

The present invention can be applied to control of an injection molding machine.

DESCRIPTION OF SYMBOLS 1 Injection type machine 10 Molding mechanism part 20 Microcomputer part (control part)
30 Display section 40 Input section 50 Input / output terminal section 61 Menu screen 62 Injection / plasticization screen 63 ON / OFF button 64 Pressurization condition setting field before plasticization 65 Pressurization setting field 66 Pressurization time setting field

Claims

In an injection molding machine including a molding condition setting unit configured to include a display unit and an input unit, and a control unit that controls driving of the entire injection molding machine,
The molding condition setting unit is configured to set a pre-plasticization pressure condition as a molding condition setting item, and an operator operates the input unit to set the pre-plasticization pressure condition. When the control unit performs the injection nozzle according to the pre-plasticization pressurization condition set in the molding condition setting unit before the plasticization process starts after the molding cycle shifts from the injection process to the cooling process. An injection molding machine which performs control to pressurize the resin inside and shifts to a plasticizing step after the control ends.
The molding condition setting unit can select whether or not to set the pre-plasticizing pressure condition, and the control unit sets the pre-plasticizing pressure condition by an operator. 2. The injection molding machine according to claim 1, wherein the molding cycle time is kept constant both when the pressure is applied and when the pre-plasticizing pressure condition is not set.
2. The injection molding machine according to claim 1, wherein the molding condition setting unit sets a resin pressure in the injection nozzle and a pressurizing time as pressurizing conditions before plasticization.
A selection button for displaying whether or not to set the pre-plasticization pressure condition is displayed on the display unit, and the operator operates the input unit to set the pre-plasticization pressure condition. 2. The injection molding machine according to claim 1, wherein when the is selected, a setting screen for the pre-plasticization pressurizing condition is displayed in a screen displaying the selection button.
The molding condition setting unit can select whether or not to set the pre-plasticizing pressure condition, and the control unit sets the pre-plasticizing pressure condition by an operator. Even when the pressure condition before plasticization is not set, the molding cycle time is kept constant,
The injection molding machine according to claim 1, wherein the molding condition setting unit sets a resin pressure in the injection nozzle and a pressurizing time as pressurizing conditions before plasticization.
The molding condition setting unit can select whether or not to set the pre-plasticizing pressure condition, and the control unit sets the pre-plasticizing pressure condition by an operator. Even when the pressure condition before plasticization is not set, the molding cycle time is kept constant,
A selection button for displaying whether or not to set the pre-plasticization pressure condition is displayed on the display unit, and the operator operates the input unit to set the pre-plasticization pressure condition. 2. The injection molding machine according to claim 1, wherein when the is selected, a setting screen for the pre-plasticization pressurizing condition is displayed in a screen displaying the selection button.
In the molding condition setting part, as the pre-plasticization pressurization condition, set the resin pressure and pressurization time in the injection nozzle,
A selection button for displaying whether or not to set the pre-plasticization pressure condition is displayed on the display unit, and the operator operates the input unit to set the pre-plasticization pressure condition. 2. The injection molding machine according to claim 1, wherein when the is selected, a setting screen for the pre-plasticization pressurizing condition is displayed in a screen displaying the selection button.
The molding condition setting unit can select whether or not to set the pre-plasticizing pressure condition, and the control unit sets the pre-plasticizing pressure condition by an operator. Even when the pressure condition before plasticization is not set, the molding cycle time is kept constant,
In the molding condition setting part, as the pre-plasticization pressurization condition, set the resin pressure and pressurization time in the injection nozzle,
A selection button for displaying whether or not to set the pre-plasticization pressure condition is displayed on the display unit, and the operator operates the input unit to set the pre-plasticization pressure condition. 2. The injection molding machine according to claim 1, wherein when the is selected, a setting screen for the pre-plasticization pressurizing condition is displayed in a screen displaying the selection button.
Operation control method for an injection molding machine that continuously produces a required molded product by repeating a molding cycle including a plasticizing step, an injection step, a pressure holding step, a cooling step, a plasticizing step of the next cycle, and a molded product taking out step. In
After the pressure holding step is completed and the cooling step is started, before the plasticizing step of the next cycle is started, a pre-plasticizing pressurizing operation for increasing the resin pressure in the injection nozzle is performed, and the plasticizing is performed. An operation control method for an injection molding machine, wherein after the pre-pressurization operation is completed, the process proceeds to the plasticizing step of the next cycle.