JP2006305777A - Control device of injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly set the control temperature of a barrel at the time of temporary stop corresponding to a resin. <P>SOLUTION: The injection molding machine is constituted so that a barrel having a heater arranged to its outer peripheral part is provided and a molten resin is injected in a mold from the injection nozzle of the leading end part of the barrel by the rotation of an injection screw while heating and melting a synthetic resin material by the heater to mold a molded product and equipped with a temperature control part 47 for controlling the temperatures of the respective places of the rear part, intermediate part and front part of the barrel and a nozzle part to predetermined temperatures, a shift minus temperature setting memory in which a shift minus temperature for uniformly lowering the temperatures of the respective places is stored, a shift absolute value temperature setting memory in which a shift absolute value temperature for lowering the temperature of the respective places to definite temperatures and a selection means for selecting the lowering of the temperatures of the respective places by either one of the shift minus temperature and the shift absolute value temperature. The temperature control part uses the temperatures selected by the selection means at the time of temporary stop of the injection molding machine to lower a control temperatures of the respective places. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an injection molding machine that injects a molten resin from a tip of a barrel that heats and melts a synthetic resin material.

  An injection molding machine has an injection nozzle formed at the tip, an injection screw is inserted in a rotatable and reciprocating manner inside, a cylindrical barrel having a heater arranged on the outer periphery, and a hopper at the rear of the barrel The synthetic resin material is charged from the outside, and the synthetic resin material is heated and melted by a heater, extruded to the tip by the rotation of an injection screw, and the molten resin is injected from the injection nozzle into a mold to form a molded product. Yes. A mold for molding the molded product is closed and held by a mold opening / closing mechanism and filled with a molten resin injected from an injection nozzle. Thereafter, the mold is separated from the injection nozzle, released from the mold opening / closing mechanism, and the molded product is taken out from the mold.

  Such a control device that controls the injection molding machine manages the temperature of the barrel that performs the operation of injecting the synthetic resin material by heating and melting. That is, the temperatures at the rear, middle, front, and nozzle portions of the barrel are controlled to predetermined temperatures. For example, the rear temperature is controlled to be the lowest predetermined temperature, the middle temperature is controlled to be about + 10 ° C. of the rear temperature, and the front temperature is about + 20 ° C. of the rear temperature. And the nozzle temperature is controlled to be about + 10 ° C. of the rear temperature.

  The control device also manages the temperature of the barrel when the injection molding machine is temporarily stopped. That is, when a shift minus temperature is set in advance to uniformly lower the control temperature of the rear, middle, front and nozzle parts in the barrel and the injection molding machine is temporarily stopped, each shift minus temperature is used. The control temperature of the place was lowered uniformly. For example, if the control temperature of the rear part at the time of molding is 300 ° C., the control temperature of the intermediate part is 310 ° C., the control temperature of the front part is 320 ° C., and the control temperature of the nozzle part is 310 ° C. If the shift minus temperature is set to -100 ° C, when the injection molding machine is temporarily stopped, the rear control temperature is 200 ° C, the intermediate control temperature is 210 ° C, and the front control temperature is 220 ° C. The control temperature of the nozzle part is 210 ° C.

  By the way, when the injection molding machine is temporarily stopped, since the flow of the molten resin in the barrel stops, even if the control temperature of each part is lowered, there is a possibility that burning may occur depending on the type of the resin. In particular, the degree of burning is increased at the front part of the barrel having a high temperature. Therefore, on the basis of lowering the control temperature of the front part to a temperature at which no burning occurs, a shift minus temperature that lowers the control temperature of other parts is set to prevent resin burn.

  However, if this is done, the temperature at the rear, middle, and nozzle of the barrel will drop more than necessary, so that the temperature at each part of the barrel will rise to a predetermined temperature required for molding when the injection molding machine is restarted. There was a problem that it took time to raise. Further, if the temperature of the barrel is lowered more than necessary, the resin characteristics may change.

  Therefore, the present invention can select a control that uniformly lowers the control temperature of each part of the barrel by the shift minus temperature and a control that lowers the control temperature of each part of the barrel to a constant temperature called a shift absolute value temperature. Thus, it is possible to provide a control device for an injection molding machine that can appropriately set the control temperature of each part of the barrel when the injection molding machine is temporarily stopped according to the resin to be used.

  The present invention forms an injection nozzle at the tip, inserts and inserts an injection screw in a rotatable and reciprocating manner inside, and puts a synthetic resin material into the rear part of a cylindrical barrel in which a heater is arranged on the outer periphery, In an injection molding machine in which this synthetic resin material is heated and melted by a heater, extruded to the tip by rotation of an injection screw, and the molten resin is injected from the injection nozzle into a mold to form a molded product. A temperature control unit that controls the temperature at multiple locations to a predetermined temperature, a shift minus temperature setting memory that sets a shift minus temperature that uniformly lowers the control temperature at each location, and a control temperature at each location is reduced to a constant temperature The shift absolute value temperature setting memory that sets the shift absolute value temperature to be set and the temperature at each location controlled by the temperature control unit The temperature control unit includes a selection unit that selects whether to decrease the temperature using the temperature setting unit, and the temperature control unit decreases the temperature controlled using the set temperature of the temperature setting memory selected by the selection unit when the injection molding machine is temporarily stopped. The purpose is to control the temperature at each location.

  According to the present invention, it is possible to select a control that uniformly lowers the control temperature of each part of the barrel by the shift minus temperature and a control that lowers the control temperature of each part of the barrel to a constant temperature called a shift absolute value temperature. Thus, it is possible to provide a control device for an injection molding machine that can appropriately set the control temperature of each part of the barrel when the injection molding machine is temporarily stopped according to the resin to be used.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. This embodiment will be described as applied to a control device for an electric injection molding machine.
FIG. 1 is a diagram showing a configuration of an electric injection molding machine. An injection molding machine main body 1 has an injection screw 4 inserted in a cylindrical barrel 3 having a hopper 2 so as to be rotatable and movable back and forth. Yes. A rear portion of the barrel 3 communicates with the hopper 2, and a synthetic resin material is supplied from the hopper 2. An injection nozzle 5 for injecting molten resin is formed at the tip of the barrel 3.

  Heaters HN, H1, H2, and H3 are arranged at predetermined intervals on the outer periphery of the nozzle portion, front portion, middle portion, and rear portion of the barrel 3, respectively. Each of the heaters HN, H1 to H3 heats the barrel 3 from the outer peripheral portion and heats and melts the synthetic resin material introduced from the hopper 2. The control temperature at the time of heating the barrel 3 is controlled such that the temperature at the rear part is the lowest, the temperature at the middle part is, for example, about + 10 ° C. of the temperature at the rear part, and the temperature at the front part is, for example, + 20 ° C. The temperature of the nozzle part is controlled to be, for example, about + 10 ° C. of the temperature of the rear part. Thereby, in the barrel 3, the melting degree of the molten resin gradually increases from the rear part toward the front part, and the sufficiently melted resin is injected from the injection nozzle 5.

  The injection screw 4 is rotationally driven by an injection servo motor 6 and moves back and forth. That is, the rotational driving force of the injection servo motor 6 is transmitted to a ball screw shaft 11 rotatably disposed on the servo bracket 10 via a transmission mechanism including a pulley 7, a timing belt 8 and a timing pulley 9. It is configured. A ball nut 12 is screwed onto the ball screw shaft 11, and the ball nut 12 is bolted to the thrust box 13. Furthermore, the rear end portion of the injection screw 4 is coupled to the thrust box 13 via an S shaft and a bearing (not shown) that are rotatably provided.

  A timing pulley 14 is coupled to the S shaft rotatably coupled to the thrust box 13, and a measuring servo motor 17 is coupled via a transmission mechanism including the timing pulley 14, the timing belt 15, and the pulley 16. The rotational driving force of the measuring servo motor 17 is transmitted to the S axis via a transmission mechanism. Thereby, the rotation of the measuring servo motor 17 is transmitted as a rotation for causing the injection screw 4 to perform a measuring operation.

  In front of the barrel 3, a mold 18 and a device 19 for opening / closing and clamping the mold 18 are arranged. The tip 4 a of the injection screw 4 moves forward in the barrel 3 when the injection nozzle 5 formed at the tip of the barrel 3 is pressed against the nozzle port 18 a of the mold 18. The generated molten resin is injected from the injection nozzle 5 and filled into the mold cavity 20.

  The device 19 for opening and closing and clamping the mold 18 is provided with a movable plate 23 that supports the other of the mold 18 via a tie bar 22 in a movable manner with respect to the fixed plate 21 that supports one of the mold 18. In addition, the movable platen 23 is attached to the toggle mechanism support plate 25 via a toggle type clamping mechanism 24. A mold clamping servomotor 26 for driving the toggle mold clamping mechanism 24 is attached to the toggle mechanism support board 25. A mold thickness adjusting mechanism 27 adjusts the mold thickness by the toggle type mold clamping mechanism 24.

  In this electric injection molding machine, first, the mold clamping servomotor 26 is driven to start the mold 18 closing, and the injection nozzle 5 of the barrel 3 is pressed against the nozzle port 18 a of the mold 18. Next, the metering servo motor 17 is driven to measure the molten resin to be injected, and then the injection servo motor 6 is driven to advance the injection screw 4 to perform injection filling of the molten resin into the mold cavity 20. .

  As shown in FIG. 2, the control device of the molding machine main body 1 in this electric injection molding machine has a CPU, a ROM, and a RAM, manages and monitors the injection molding machine main body, and controls each part. 31 is provided. Further, it has a CPU, ROM and RAM, and has a sequence processing unit 32 for controlling the operation sequence of the injection molding machine main body, and has a CPU, ROM and RAM, and controls the injection servo motor 6 and the metering servo motor 17. A servo command unit 33 is provided. The main control unit 31, sequence processing unit 32, and servo command unit 33 are electrically connected to each other by a bus line 34.

  The servo command unit 33 controls the servo amplifier 35 to drive the injection servo motor 6. The rotation and current value of the injection servo motor 6 are detected by the detection unit 36. The servo command section 33 receives a detection signal from the detection section 36, detects the movement position, rotation speed, and motor current value of the injection screw 4, and performs feedback control for controlling the injection servo motor 6 based on the detected position. .

The servo command unit 33 controls the servo amplifier 37 to drive the measuring servo motor 17. Then, the rotation and current value of the measuring servo motor 17 are detected by the detection unit 38. The servo command unit 33 receives a detection signal from the detection unit 38, detects the movement position, rotation speed, and motor current value of the injection screw 4, and performs feedback control for controlling the measuring servo motor 17 based on the detected position. .
An I / O 40 and the like are electrically connected to the sequence processing unit 32 via an I / O bus 39.

  The main control unit 31 includes a communication interface unit. An HMI (human machine interface) unit 41 having a CPU, a ROM, a RAM, and a general-purpose OS (operating system) is connected to a LAN 42 such as Ethernet (registered trademark). Connected by. The HMI unit 41 is composed of, for example, a personal computer, and is connected to a display unit of a display unit 43 with a touch panel in which a touch panel is arranged on a liquid crystal display screen, and controls the display unit.

  Further, the main control unit 31 connects an operation panel unit 44 provided with a plurality of mechanical operation switches by a cable 45, and connects a touch panel of the display unit with a touch panel 43 by a cable 46. From temperature detectors DHN, D1, D2, and D3 that control the heating of a plurality of heaters HN, H1 to H3 arranged on the outer periphery of the barrel 3 and detect the temperatures of the nozzle, front, middle, and rear parts, respectively. A temperature control unit 47 that takes in a temperature detection signal and controls energization of the heaters HN and H1 to H3 is connected by a cable 48.

  As shown in FIG. 3, the HMI unit 41 communicates with the main control unit 31 via a CPU 51 constituting a control unit main body, a ROM 52 storing program data, a RAM 53 provided with a memory used for data processing, and the LAN 42. A non-volatile storage medium such as a compact flash (registered trademark) card or a hard disk storing a communication interface (I / F) 54 for performing display, a display controller 55 for controlling display of the display unit 43 with a touch panel, a general-purpose OS, etc. A storage medium interface (I / F) 58 that communicates data with this external storage medium 57 is provided by connecting to the storage device 56 and an external storage medium 57 such as an optical disk, and electrically connected to each other via a bus line 59. ing.

  The display unit with touch panel 43 is display-controlled by the HMI unit 41 via the display controller 55. A key signal from the display unit with a touch panel 43 is input to the main control unit 31. Of the key signals input by the main control unit 31, signals necessary for the HMI unit 41 are transmitted to the LAN 42. The data is transmitted to the HMI unit 41 via

  As shown in FIG. 4, a shift minus temperature setting memory 561 that sets a shift minus temperature and a shift absolute value temperature setting memory 562 that sets a shift absolute value temperature are formed in the storage medium of the storage device 56. The shift minus temperature is a temperature for uniformly lowering the control temperature of each part of the barrel 3 when the operation of the injection molding machine is temporarily stopped, for example, −100 ° C. The shift absolute value temperature is the operation of the injection molding machine. Is a temperature for lowering the control temperature of each part of the barrel 3 to a constant temperature when is temporarily stopped.

  The display unit with a touch panel 43 displays the screen shown in FIG. 5, and when the injection molding machine is temporarily stopped, the control temperature of each part of the barrel 3 is lowered using the shift minus temperature or the absolute value of the shift is displayed. A shift operation condition setting screen A for selecting whether to lower the control temperature of each part of the barrel 3 using the temperature is displayed.

When the mode selection “minus temperature” is selected on the shift operation condition setting screen A, the shift minus temperature is read from the shift minus temperature setting memory 561. On the screen A, when the “absolute value temperature” of the mode selection is selected, the shift absolute value temperature is read from the shift absolute value temperature setting memory 562. (Selection means)
Then, the read shift minus temperature or shift absolute value temperature is sent to the main control unit 31.

  The main control unit 31 receives the shift minus temperature or the shift absolute value temperature and temporarily stores it in, for example, a RAM. When the injection molding machine is temporarily stopped, the main control unit 31 changes the control temperature of each part of the barrel 3 controlled by the temperature control unit 47 using the temporarily stored shift minus temperature or shift absolute value temperature. To do.

  In such a configuration, when molding a molded product, the touch panel is operated to select the molding condition setting while the screen for selecting the molding condition setting is displayed on the display unit of the display unit 43 with a touch panel. Then, a screen for setting molding conditions is displayed on the display unit. Then, the operator operates on this setting screen, and sets and confirms the molding conditions prior to the injection molding work. Further, when the injection molding machine is temporarily stopped, the screen A is used to select whether to use the shift minus temperature or the shift absolute value temperature.

  And based on the synthetic resin material used for shaping | molding, shift absolute value temperature is selected, for example. As a result, the HMI unit 41 reads the shift absolute value temperature from the shift absolute value temperature setting memory 562 and sends it to the main control unit 31. The main control unit 31 temporarily stores the received shift absolute value temperature in the RAM.

  When the setting of molding conditions is completed, the injection molding machine main body 1 is controlled to start injection molding. In the injection molding, the main control unit 31 controls the temperature control unit 47 to melt the synthetic resin material put into the barrel 3 from the hopper 2 by heating with the heaters HN, H1 to H3, and the sequence processing unit 32 and the servo. The command unit 33 is controlled.

  That is, the synthetic resin material put into the barrel 3 from the hopper 2 is first melted by heating by the heater H3 at the rear part. The degree of melting at this time is small, and the molten resin is hard. The molten resin is pushed forward by the rotation of the injection screw 4, further melted by heating by the heater H 2 at the intermediate portion, and melted by the heating by the heater H 1 to a sufficient amount for injection at the front portion. The molten resin is injected and filled into the mold cavity 20 through the injection nozzle 5 heated by the heater HN. When the filling is completed, the device 19 for opening / closing and clamping the mold 18 is operated to separate the mold 18 from the barrel 3 and to open the mold 18, and the molded product is taken out. Thereafter, this molding is repeated.

  During the molding operation, if the operation of the injection molding machine may temporarily stop, the main control unit 31 controls the temperature control unit 47, and the rear and middle parts of the barrel 3 controlled by the temperature control unit 47. The temperature of the front part and the nozzle part are all changed to the shift absolute value temperature. For example, if the temperature of the rear part, middle part, front part and nozzle part of the barrel 3 at the time of injection molding is 300 ° C., 310 ° C., 320 ° C., 310 ° C. and the shift absolute value temperature is 210 ° C., the temporary injection molding machine The temperature of the rear part, the middle part, the front part, and the nozzle part of the barrel 3 at the time of stopping are all controlled to a constant temperature of 210 ° C.

  Thus, for example, when using a resin that may cause resin burning when left at 220 ° C. for a while, it is possible to prevent the resin burning from occurring by performing such temperature control. Moreover, since the temperature of the barrel 3 is not lowered more than necessary, the temperature of the barrel 3 can be raised in a relatively short time when the injection molding machine is operated again. Moreover, there is no possibility that the characteristics of the resin will change.

  When the shift minus temperature is selected based on the synthetic resin material used for molding, the HMI unit 41 reads the shift minus temperature from the shift minus temperature setting memory 561 and sends it to the main control unit 31. The main control unit 31 temporarily stores the received shift minus temperature in the RAM.

  When the operation of the injection molding machine may temporarily stop during the molding operation, the main control unit 31 controls the temperature control unit 47, and the rear part of the barrel 3 controlled by the temperature control unit 47, the middle The temperature of the head, front, and nozzle is uniformly reduced by the shift minus temperature. For example, if the temperature of the rear part, the middle part, the front part, and the nozzle part of the barrel 3 at the time of injection molding is 300 ° C., 310 ° C., 320 ° C., 310 ° C. and the shift minus temperature is −100 ° C., the temporary injection molding machine The temperatures of the rear part, the middle part, the front part, and the nozzle part of the barrel 3 at the time of stopping are controlled to 200 ° C, 210 ° C, 220 ° C, and 210 ° C.

Thus, for example, such temperature control can be performed when using a resin that is not likely to cause resin burn even if left at 220 ° C. for a while. Further, in this temperature control, the temperature of each part of the barrel 3 when the injection molding machine is operated again may be raised by 100 ° C., and the temperature control becomes simple.
Thus, the temperature of each part of the barrel 3 when the injection molding machine is temporarily stopped can be appropriately set according to the synthetic resin used for molding.

In this embodiment, the place where the temperature control of the barrel 3 is performed is the four parts of the rear part, the intermediate part, the front part, and the nozzle part. Or five or more places may be sufficient.
In this embodiment, the display unit with a touch panel is provided separately from the HMI unit, but may be integrated with the HMI unit.

The figure which shows the structure of the electric injection molding machine which concerns on one embodiment of this invention. The block diagram of the control apparatus of the injection molding machine main body which concerns on the same embodiment. The block diagram which shows the structure of the HMI part in the control apparatus of FIG. FIG. 4 is a diagram showing a memory configuration of a main part formed in the storage device of FIG. 3. The figure which shows the example of a display screen for the shift operation condition setting in the display part with a touch panel of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Injection molding machine main body, 18 ... Mold, 31 ... Main control part, 32 ... Sequence processing part, 41 ... HMI (human machine interface) part, 43 ... Display part with a touch panel, 47 ... Temperature control part, 51 ... CPU 56, storage device, HN, H1, H2, H3, heater, DHN, D1, D2, D3, temperature detector.

Claims (1)

An injection nozzle is formed at the tip, an injection screw is inserted in a rotatable and reciprocating manner inside, and a synthetic resin material is introduced into the rear part of a cylindrical barrel having a heater arranged on the outer periphery. In an injection molding machine that molds a molded product by injecting molten resin from the injection nozzle to a mold by extruding to the tip by rotating the injection screw while heating and melting with the heater,
A temperature control unit that controls the heater to control the temperature at a plurality of locations in the barrel to a predetermined temperature, and
A shift minus temperature setting memory that sets a shift minus temperature that uniformly lowers the control temperature of each of the parts;
A shift absolute value temperature setting memory that sets a shift absolute value temperature that lowers the control temperature of each part to a constant temperature; and
A selection means for selecting which one of the temperatures set in each temperature setting memory to lower the temperature of each location controlled by the temperature control unit;
The temperature control unit controls the temperature of each part by lowering the temperature controlled using the set temperature of the temperature setting memory selected by the selection means when the injection molding machine is temporarily stopped. Control device for injection molding machine.

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