Abstract:
An electric discharge machine has a hand operation panel, which is provided with a manual pulse generator with a rotating part. The manual pulse generator generates a pulse signal corresponding to a rotation angle position of the rotating part. Further, the manual pulse generator outputs a move command for changing (i.e., increasing or decreasing) a relative distance between a tool electrode and a workpiece and commands for changing set values of machining conditions, based on the pulse signal from the manual pulse generator.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a wire electric discharge machine comprising a hand operation panel. 
         [0003]    2. Description of the Related Art 
         [0004]    In a wire electric discharge machine, it is necessary to set axial movement during the machining and machining conditions for controlling electric discharge machining, such as a machining voltage, quiescent time, wire tension, etc. 
         [0005]    Japanese Patent Application Laid-Open No. 4-122524 discloses a technique in which machining conditions are selected on a display screen attached to the body of an electric discharge machine and tables are manually positioned using a manual pulse generator. In setting the machining conditions, in particular, according to this technique, values for the machining condition setting are input on the display screen that is located at a distance from the machining position. Therefore, the machining state cannot be observed near the machining position during the machining as the machining conditions are set. 
         [0006]    While a hand operation panel is used to move axes and tables according to some conventional techniques, machining conditions are set by inputting values on a control panel. Therefore, the machining state cannot be observed near the machining position during the machining as the machining conditions of an electric discharge machine are set. 
         [0007]    In the case where the axes and tables are moved on the hand operation panel, moreover, the hand operation panel is configured so that an axis is moved at a specified speed while a button for the specified speed is being manually depressed. If the axis moving speed is expected to be changed, therefore, it is necessary to manually push a button for another specified speed. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, the object of the present invention is to provide an electric discharge machine capable of improving the operability for the movement of an axis or the like and machining condition setting. 
         [0009]    An electric discharge machine according to the present invention has a hand operation panel, which includes a manual pulse generator provided with a rotating part rotatable in clockwise and counterclockwise directions. The manual pulse generator generates a pulse signal corresponding to a rotation angle position of the rotating part. The manual pulse generator is configured to output a move command for changing a relative distance between a tool electrode and a workpiece and commands for changing set values other than the move command, based on the pulse signal from the manual pulse generator. 
         [0010]    In the electric discharge machine according to the present invention, the hand operation panel is provided with the manual pulse generator configured to generate the pulse signal corresponding to the rotation angle of the rotating part. The manual pulse generator can output the move command for changing the relative distance between the tool electrode and the workpiece and commands for changing the set values other than the move command. Thus, the commands can be output by setting the rotation angle of the rotating part so that the operability is improved. Also, the set values other than the move command can be handled by means of the hand operation panel, so that the machining state can be observed as the set values are changed. 
         [0011]    The hand operation panel may further comprise a changeover switch configured to determine whether to use the pulse signal from the manual pulse generator for the move command for changing the relative distance between the tool electrode and the workpiece or to use the pulse signal for the commands for changing the set values other than the move command. 
         [0012]    According to this arrangement, the hand operation panel is provided with the function changeover switch for changeover between the move command and the commands for changing the set values other than the move command, so that the move command for an axis or the like and the commands for changing the set values other than the move command can be output alternatively. 
         [0013]    The set values other than the move command may include at least one machining condition of the electric discharge machine. Further, the machining condition may include a machining voltage, a discharge quiescent time, and/or a wire tension. 
         [0014]    The hand operation panel may further comprise a display section configured to display an axis feed rate based on the move command and a value of the machining condition. 
         [0015]    According to the present invention, there can be provided an electric discharge machine capable of improving the operability for the movement of an axis or the like and machining condition setting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above and other objects and features of the present invention will be obvious from the ensuing description of embodiments with reference to the accompanying drawings, in which: 
           [0017]      FIG. 1  is a block diagram showing one embodiment of an electric discharge machine according to the present invention; 
           [0018]      FIG. 2  is a diagram showing a configuration of a hand operation panel in a control section of the electric discharge machine of  FIG. 1 ; 
           [0019]      FIG. 3  is a diagram illustrating a configuration of the hand operation panel of  FIG. 2  in which its function changeover switch is provided with only a single button such that an axis feed control function, as a first function CA1, and a machining condition change function, as a second function CA2, are alternately changed each time the button is pushed; 
           [0020]      FIG. 4  is a diagram showing how machining conditions are changed by the function changeover switch; and 
           [0021]      FIG. 5  is a diagram showing an example of axis feed control (change of an axis movement function) by means of the function changeover switch on the hand operation panel of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]      FIG. 1  is a block diagram showing one embodiment of an electric discharge machine according to the present invention. 
         [0023]    A control section  1  of the electric discharge machine comprises a hand operation panel  10 , control panel  20 , CPU  30 , memory  32 , axis control circuit  42 , and machining condition control circuit  52 . The hand operation panel  10  is provided with a manual pulse generator  12 , function changeover switch  14 , and display section  16  (described later). Further, the control panel  20  is provided with an axis movement key  22  and a machining condition setting key  24 . 
         [0024]    The CPU  30  is connected, via interfaces  40 , with the manual pulse generator  12  and the function changeover switch  14  on the hand operation panel  10  or the axis movement key  22  and the machining condition setting key  24  on the control panel  20 . The CPU  30  is also connected with the axis control circuit  42  and the machining condition control circuit  52 . Outputs from the manual pulse generator  12 , function changeover switch  14 , axis movement key  22 , and machining condition setting key  24  are input to the CPU  30 . Further, the axis control circuit  42  is connected with the an axis feed motor  44 , and outputs axis move commands received from the CPU  30  to the axis feed motor  44 . Furthermore, the machining condition control circuit  52  is connected with a machining power supply  54 , working fluid pump  56 , and wire feed motor  58 . The machining condition control circuit  52  outputs machining conditions given by the CPU  30  to the machining power supply  54  and the like. 
         [0025]      FIG. 2  is a diagram showing a configuration of the hand operation panel  10  shown in  FIG. 1 . 
         [0026]    The hand operation panel  10  is provided with the manual pulse generator  12 , which has a rotating part  17  rotatable in clockwise and counterclockwise directions, function changeover switch  14 , and display section  16 . The manual pulse generator  12  generates pulses proportional to the rotation amount of the rotating part  17 . The function changeover switch  14  determines whether to use the pulses generated by the manual pulse generator  12  for axis feed control or for change of machining conditions. 
         [0027]    If the pulses generated by the manual pulse generator  12  are determined by the function changeover switch  14  to be used for axis feed control, they are delivered to the CPU  30  through an interface  40 . Thereupon, the CPU  30  outputs the axis move commands corresponding to the pulses to the axis control circuit  42 . 
         [0028]    If the pulses generated by the manual pulse generator  12  are determined by the function changeover switch  14  to be used for machining condition change, in contrast, they are delivered to the CPU  30  through the interface  40 . Thereupon, the CPU  30  outputs the machining conditions corresponding to the pulses to the machining condition control circuit  52 . 
         [0029]    An axis feed rate, values of machining conditions, etc., are displayed on the display section  16 . 
         [0030]    The manual pulse generator  12  of the hand operation panel  10  generates pulses proportional to the rotation amount of the rotating part  17 . If the hand operation panel  10  is used for axis feed control, the rotating part  17  of the manual pulse generator  12  is rotated in the clockwise direction (direction (+)) so that the axis moves in a positive direction or is rotated in the counterclockwise direction (direction (−)) so that the axis moves in a negative direction. 
         [0031]    If the hand operation panel  10  is used for machining condition change or the like, in contrast, the rotating part  17  of the manual pulse generator  12  is rotated in the clockwise direction (direction (+)) so that parameters of the machining conditions to be changed are increased by addition, and is rotated in the counterclockwise direction (direction (−)) so that the parameters of the machining conditions to be changed are reduced by subtraction. 
         [0032]    The function changeover switch  14  on the hand operation panel  10  may be provided with a plurality of buttons (not shown) so that each function can be changed by pushing the button (switch) corresponding to the function. Alternatively, the hand operation panel  10  may be provided with only a single switch as the function changeover switch  14  so that the function can be changed each time the switch is pushed. 
         [0033]      FIG. 3  is a diagram illustrating a configuration of the hand operation panel  10  of  FIG. 2  in which its function changeover switch  14  is provided with only a single button (not shown) such that an axis feed control function, as a first function CA1, and a machining condition change function, as a second function CA2, are alternately changed each time the button is pushed. 
         [0034]      FIG. 4  is a diagram showing how the machining conditions are changed by the function changeover switch  14 . 
         [0035]    The function changeover switch  14  on the hand operation panel  10  may be provided with a plurality of buttons for machining condition change, as well as for function change shown in  FIG. 3 , so that the machining conditions can be changed by pushing the buttons corresponding to the machining conditions, individually. Alternatively, the function changeover switch  14  may be provided with only a single button such that the machining conditions can be sequentially changed each time the button is pushed. The example of  FIG. 4  is configured so that a machining voltage (first machining condition CB1), discharge quiescent time (second machining condition CB2), wire tension (third machining condition CB3), and working fluid pressure (fourth machining condition CB4) are sequentially changed. 
         [0036]    In the arrangement described above, the function changeover switch  14  is configured to determine whether to use the pulses generated by the manual pulse generator  12  for axis feed control (or to change over to the axis feed control function) or for change of machining conditions (or to change over to the machining condition change function). However, the function changeover switch  14  is not limited to the changeover between these two functions, and may alternatively be used for the change of other set values, such as the water level of a working tank of the electric discharge machine, the specific resistance of a working fluid, and the like (set value change function). 
         [0037]      FIG. 5  is a diagram showing an example of axis feed control (change of an axis movement function) by means of the function changeover switch  14 . 
         [0038]    The function changeover switch  14  on the hand operation panel  10  may be provided with a plurality of buttons for axis feed control (change of the axis movement function), as well as for the function change shown in  FIG. 3 , so that the axis movement function can be changed by pushing the buttons corresponding to the axis movement functions, individually. Alternatively, the function changeover switch  14  may be provided with only a single button for axis feed control (change of the axis movement function) such that the axis movement function can be sequentially changed each time the button is pushed. The example of  FIG. 5  is configured so that a U-axis (first axis CC1), V-axis (second axis CC2), X-axis (third axis CC3), and Y-axis (fourth axis CC4) are sequentially changed over to one another as an object of axis feed control each time the button is pushed. 
         [0039]    Thus, according to the present invention, the axis feed control (axis movement function), which has conventionally been changed by pushing a button on the hand operation panel, is performed (i.e., a pulse signal is generated) depending on the rotation angle of the rotating part that constitutes the manual pulse generator of the hand operation panel. Specifically, the rotating part is quickly rotated when the axis subject to the axis feed control is expected to be quickly moved, and is slowly rotated when the target axis is expected to be slowly moved. In this way, the operability is improved compared with the case where the buttons are used for this purpose. 
         [0040]    Further, the hand operation panel enables adjustments, such as machining condition change, other than the axis feed control (axis movement function). Therefore, the machining state can be observed as the machining conditions are changed, and the control panel in a remote place need not be accessed in changing the machining conditions, so that the operability is improved.