Abstract:
In an injection molding machine configured to extrude a melted resin under temperature control and inject the resin into metal molds to provide a molded product, there are provided an HMI section having a built-in general-purpose operating system and configured to control a display section equipped with a touch panel, control modules, such as a main control section, a sequence processing section and a servo command section, having a dedicated microprocessor for each control element of the injection molding machine, and a driver section having servo amplifiers, hydraulic drivers, and so on, configured to be controlled by the control modules and to drive-control an actuator of the injection molding machine, in which, by variously combining together the control modules, it is possible to provide various kinds of injection molding machines, that is, an electric operation type, a hydraulic type and a hybrid type of these combination.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-117148, filed Apr. 14, 2005, the entire contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a control apparatus for use in an injection molding machine. 
   2. Description of the Related Art 
   Known is, for example, an injection molding machine as disclosed in Jpn. Pat. Appln Kokai Publication No. 2001-191383. 
   An injection molding machine may use various kinds of controls, such as in the injection, in measuring, in mold opening and closing, in extruding, and in the application of temperature. 
   In the injection molding machine of the above Publication, control of the injection molding is performed by a specific control device that is usable only for the injection molding machine. 
   A type of Control of an actuator in the injection molding machine, as well as measuring, mold opening/closing and extrusion operations is selected depending on whether an electrical operation type or a hydraulic type is used. 
   Thus, the use of such control types differs depending on whether an electrical type of operation, a hydraulic type of operation or a hybrid type of operation is used. 
   In the prior art, when a control target is an electrical operation of an actuator, a dedicated control device has been used and, when the control target is a hydraulic operation, a corresponding special control device has been used. 
   Therefore, the conventional injection molding device requires a dedicated control device. As a result it is difficult to provide a general-purpose machine. 
   BRIEF SUMMARY OF THE INVENTION 
   An aspect of the present invention is to provide a control device for use in an injection molding machine. When a control target in the injection molding machine is changed, the control device can be tailored to each control element. As a result, the control device can handle such a situation through a combination of control modules. Thus, a general-purpose machine unit can be provided. 
   In one aspect of an embodiment of the present invention there is provided an injection molding machine for heating a synthetic resin material and, injecting a predetermined amount of molten synthetic resin material into a melted mold to obtain a molded product. The injection molding machine comprises a human/machine interface device having a general-purpose operating system. The interface device is configured to control a display section, to control a plurality of control modules having a dedicated microprocessor for each control element of the injection molding machine, and to control a driver, the driver section being configured to drive-control an actuator of the injection molding machine, wherein various kinds of injection molding controls can be performed through a specific combination of various control modules. 
   Additional aspects of various embodiments the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Aspects of the invention may be realized and obtained by means of instrumentation and combinations particularly pointed out hereinafter. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
       FIG. 1  shows a structure of an electrical operating type injection molding machine, according to one embodiment of the present invention; 
       FIG. 2  is a block diagram showing a control device of the injection molding machine body, according to an embodiment of the present invention; 
       FIG. 3  is a block diagram of a control device of the injection molding machine body when used in a hydraulic-type injection molding machine, according to an embodiment of the present invention; and 
       FIG. 4  is a block diagram of a control device of the injection molding machine body when used in a hybrid-type injection molding machine, according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   One embodiment of the present invention will be described below with reference to the accompanying drawing. 
     FIG. 1  shows an electrically operated injection molding machine. 
   The injection molding machine includes an injection molding machine body  1 , an injection screw  4  arranged so as to be inserted into a cylindrical barrel  3 . The injection machine also includes a hopper  2 . 
   The injection screw  4  is rotatable in the barrel  3  and freely movable forward and backward. 
   The barrel  3  communicates with the hopper  2 . A synthetic resin material is fed into the barrel through the hopper  2 . A plurality of heaters, not shown, are arranged at predetermined intervals on the outer periphery side of the barrel  3 . These heaters are adapted to heat the outer periphery of the barrel and melt the resin material fed into the barrel  3 . 
   The barrel  3  has an injection nozzle  5  at a forward end of the barrel  3  to allow the melted synthetic resin material to be injected. 
   A heating temperature of the barrel  3  is controlled by the plurality of heaters so that the melting degree of the melted resin material gradually increases when the resin moves toward the forward end of the barrel  3 . 
   The injection screw  4  is rotatably driven by a servomotor  6  for injection and moved forward and backward. That is, the servomotor  6  for injection transmits its rotation to a ball screw shaft  11  through a transmission mechanism comprising a pulley  7 , a timing belt  8  and a timing pulley  9 . 
   The ball screw shaft  11  is rotatably provided in a servo bracket  10 . 
   The ball screw shaft  11  is set in a ball nut  12 . The ball nut  12  is fixed by bolts to a thrust box  13 . 
   The injection screw  4  is rotatably joined at its rear end portion to the thrust box  13  through an S shaft and bearing (not shown). 
   The S shaft is rotatably connected to the thrust box  13  and mounted to a timing pulley  14 . 
   A servomotor  17  is also provided. The servomotor  17  has a rotation shaft which is connected to a pulley  16 . 
   A timing belt  15  is provided between the timing pulley  14  and the pulley  16 . 
   The timing pulley  14 , timing belt  15  and pulley  16  constitute a transmission mechanism. 
   The servomotor  17  moves the injection screw  4  material which is to be injected forward, determining an amount of the melted resin. The servomotor  17  transmits its rotation to the S shaft as set out above through the associated transmission mechanism as set out above to allow the injection screw  4  to be rotated. 
   The forward moving position of the injection screw  4  is determined by an amount of synthetic resin material injected. 
   In the forward position of the barrel  3  are provided metal mold halves  18  and a device  19  for opening/closing and clamping the metal molds. 
   When the melted resin material is injected from the injection nozzle  5 , the injection nozzle  5  is pushed into a nozzle inlet  18   a  of one metal mold half  18 . In this state, the forward end  4   a  of the injection screw  4  is moved forward and, by doing so, allows the resin material which is melted in the barrel  3  to be injected through the injection nozzle  5 . Thus, the resin material is charged into a cavity  20  defined by the metal mold halves  18 . 
   The device  19  has a fixing plate  21  that supports one of the metal mold halves  18 . A movable plate  23  is provided. The movable plate  23  holds a tie bar  22  which in turn supports the fixing plate  21 . The movable plate  23  can move toward and away from the fixing plate  21 . 
   The device  19  attaches the movable plate  23  to a toggle mechanism support plate  25  through a toggle type mold clamping mechanism  24 . 
   A servomotor  26  is provided on the toggle mechanism support plate  25  to drive the toggle type clamping mechanism  24 . A mold thickness adjusting mechanism  27  is provided. The mechanism  27  adjusts a mold thickness when the toggle type mold clamping mechanism  24  effects the mold clamping operation. 
   In the electrical type injection molding machine thus structured, the servomotor  26  is first driven for mold clamping. By doing so, the metal molds  18  start their mold closing operation. In addition, the injection nozzle  5  of the barrel  3  is pushed into the nozzle  18   a  of the mold halves  18 . 
   Then, the measuring servomotor  17 , while being rotated, moves the injection screw  4  forward and effects a quantity of the melted resin material injected. Then, the injection servomotor  6  rotates the injection screw  4  to inject the melted resin. 
   The barrel  3  injects the melted resin through the injection nozzle  5  and charges the melted resin into the cavity  20  of the metal molds  18 . 
   As shown in  FIG. 2 , a control device of the electrical type injection molding machine  1  includes a main control section  31  for controlling each part of the injection molding machine, a sequence processing section  32  and a servo command section  33 . 
   The main control section  31  includes a CPU, ROM, RAM, etc. The main control section  31  allows to manage and monitor the injection molding machine  1 . 
   The sequence processing section  32  has a CPU, ROM, RAM, etc. The sequence processing section  32  allows to control the operation sequence of the injection molding machine  1 . 
   The servo command section  33  has a CPU, ROM, RAM, etc. The serve command section  33  allows to control the injection servomotor  6  and the measuring servomotor  17 . 
   The main control section  31 , the sequence processing section  32  and the servo command section  33  are electrically connected together through a bus line  34 . 
   The servo command section  33  controls a servo amplifier  35  in a driver section and drives the injection servomotor  6 . The rotation and current value of the injection servomotor  6  are detected by a detection section  36 . 
   The servo command section  33  receives a signal from the detection section  36  and detects the moved position and rotation speed of the injection screw  4  and the current value in the motor. Furthermore, the servo command section  33  performs feedback control based on the detected moved position of screw  4  and rotation speed of the screw  4  and current value in the motor and thus controls the servomotor  6 . 
   The servo command section  33  controls the servo amplifier  35  in the driver section and drives the servomotor  17  for measurement. The rotation and current value of the measuring servomotor  17  are detected by a detection section  38 . 
   The servo command section  33  receives a signal from the detection section  38  and detects the moved position and rotation speed of the injection screw  4  and current value of the servomotor. Furthermore, the servo command section  33  performs feedback control based on the moved position of screw  4  and rotation speed of the screw  4  and current value in the servomotor  17 . The servo command section  33  also controls the servomotor  17  for measurement. 
   An I/O  40 , etc., is electrically connected via I/O bus  39  to the sequence processing section  32 . 
   The main control section  31 , sequence processing section  32  and servo command section  33  each constitute a control module with a dedicated microprocessor for each control module. 
   The main control section  31  includes a communication interface section such as HMI section  41 . HMI section  41  is a human/machine interface device that is electrically connected to the main control section  31  through a LAN  42  such as Ethernet (registered trademark name). 
   The HMI section  41  includes a CPU, ROM, RAM, etc., and general-purpose OS (operating system). 
   The HMI section  41  is comprised of, for example, a personal computer and connected to a display section  43 . The display section  43  has a touch panel on a liquid crystal display screen to allow the display screen to be controlled. 
   The main control section  31  is connected via a cable  45  to an operation panel section  44 . The operation panel section  44  has a plurality of mechanical operation switches. 
   The main control section  31  is connected via a cable  46  to the touch panel of the display section  43 . 
   The main control section  31  is connected via a cable  48  to a temperature control section  47 . The temperature control section  47  controls the heating temperature of the plurality of heaters arranged on the outer periphery of the barrel  3 . 
   The display section  43  allows to display control parameters via the HMI section  41  and allows touch panel of the display section  43  to be controlled by the main control section  31 . 
   The display section  43  outputs a key signal to the main control section  31  by finger-touching any corresponding key on the touch panel on the display screen. 
   In such arrangement, the main control section  31  controls the temperature control section  47 . The temperature control section  47  controls the heating temperature of the plurality of heaters to melt the synthetic resin material transferred from the hopper  2  into the barrel  3 . 
   When the resin material is injected through the injection nozzle  5  of the barrel  3  into the cavity  20 , the sequence processing section  32  and servo command section  33  are controlled. 
   First, the servo command section  33  controls the servo amplifiers  37  and drives the measuring servomotor  17 . The servomotor  17  rotates the injection screw  4  to move the melted resin forward and determine the melted resin amount injected from the barrel  3 . 
   Then, while the injection screw  4  is rotated, the injecting servomotor  6  is driven to move the resin forward. The injection screw  4  pushes the melted resin through the injection nozzle  5  via the forward end  4   a . By doing so, the mold cavity  20  is filled with the melted resin which is through the injection nozzle  5  past the nozzle inlet  18   a  of the mold halves  18 . 
   When the filling of the melted resin material is finished, the device  19  is operated for the closing and clamping of the mold halves  18 . The mold halves  18  are moved apart from the barrel  3 . The device  19  opens the metal molds and a molded product is taken out from the metal mold halves  18 . 
   The above description of operation is for the electrical type injection molding machine. However, it is also possible to use a hydraulic type injection molding machine in place of the electrical type injection molding machine. 
   In the case of the hydraulic type injection molding machine, a hydraulic driver for relief/flow control is used. In this case, the injection servomotor  6  and measuring servo motor  17  may not be used. 
   A control device of the hydraulic type injection molding machine does not use the servo command section  33  and servo amplifiers  35 ,  37  connected to the servo command section  33  as well as the injection servomotor  6 , measuring servomotor  17  and so on. 
   As shown in  FIG. 3 , the control device disconnects the servo command section  33  and servo amplifiers  35 ,  37  connected to the section  33  as well as the injection servomotor  6  and measuring servomotor  17  and so on and, instead, connects a hydraulic I/O  51  to a bus line  34 . In this case, the hydraulic I/O  51  is connected to hydraulic drivers  52  and  53 . 
   The hydraulic driver  52  moves the injection screw  4  forward and backward so that the injection screw  4  injects the molted resin. On the other hand, the hydraulic driver  53  moves the injection screw forward and backward so that the hydraulic driver  53  measures an amount of melted resin injected. 
   When the injection molding machine is changed from the electrical type injection molding machine to the hydraulic type injection molding machine, a change is made to the configuration of the injection screw. Indeed, the injection screw  4  driven by the injection servomotor  6  in an electrical type injection molding machine is changed to an injection screw driven under a hydraulic pressure in a hydraulic type injection molding machine. 
   A barrel  3  having a different structure is employed in the hydraulic type injection molding machine compared to a barrel  3  in the electrical operation type injection molding machine. As such, the injection molding machine per se maybe wholly replaced. 
   However, the control device has a dedicated CPU for each of the main control section  31 , the sequence processing section  32 , and the servo command section  33 . The control device provides a control module, that is, a unit modularized for each control element. Therefore, the main control section  31 , the sequence processing section  32 , and the servo command section  33  in the main control device are individually exchangeable. 
   In this way, when the injection molding machine is changed from the electrical operation type to the hydraulic type, the servo command section  33  and so on are disconnected from an associated circuit and, instead, the hydraulic I/O  51  is connected to the bus line  34 . The hydraulic I/O  51  is connected to hydraulic drivers  52  and  53 . In this case, if the sequence processing section  32  in the electrical type injection molding machine is different from a sequence processing section  32  in the hydraulic type injection molding machine, an appropriate hydraulic type sequence processing section can be used. 
   As a result, even if a change is made from the electrical type injection molding machine to the hydraulic type injection molding machine, replacing the control device as a whole, may not be needed. In this case, an exchange may be made in control module units. 
   It is also possible for the injection molding machine to use any proper electrical type/hydraulic type combination as a hybrid type injection molding machine. 
   A control device that can be used in the hybrid type injection molding machine, is shown in  FIG. 4 . A hydraulic I/O  51  is connected to a bus line  34  as in the control device shown in  FIG. 2 . The hydraulic I/O  51  is connected to the hydraulic drivers  52  and  53 . Furthermore, a sequence processing section  32  is replaced by a hybrid type. Thus, it may not be necessary to replace the control device as a whole. 
   Incidentally, the sequence processing section  32  has initially a built-in sequence control program corresponding to an electrical, a hydraulic and a hybrid type operation. The sequence processing section  32  is constructed so that any corresponding sequence control program can be selected. 
   Accordingly, the sequence processing section  32  is not replaced by a new one and can be readily tailored to meet a specific need by selecting any sequence control program. 
   As evident from the above, even if the injection molding machine is changed to any of the electrical, hydraulic and hybrid type operation, the control device does not need to be changed as a whole. It is possible to readily adapt to any configuration through the change of any possible control module combination. As a result, the control device provides an excellent general-purpose device and provides higher economic benefits. 
   Furthermore, the control device described herein achieves an enhanced processing capability, by allowing the exchange of the main control section  31  and sequence processing section  32 .