Programming of CNC Machines. Ken Evans

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MPG-Manual Pulse Generator

      Pressing this button activates the manual handle feed mode for the selected axis. This handle is known as the Manual Pulse Generator. Pressing the MPG button places the machine in the HANDLE mode. This mode enables manual control of axis movements (for X, Y or Z, or for rotational axes A, B or C) by use of the handle after activating their respective axis buttons. For instance, press MPG then press X and then use the handle to move to the desired position along the X axis. By turning the handle clockwise, you can move the tool in a positive direction with respect to the position of the coordinate system. By turning the handle counterclockwise, the tool is moved in a negative direction with respect to the position of the coordinate system. The handle contains 100 notches, each of which corresponds to an increment (distance to be moved). Turning the handle, you can feel the displacement from one notch to the next.

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      Figure 11 Manual Pulse Generator (MPG) Handle

      To set the magnitude for the distance to be moved, press one of the Speed/Multiply buttons as described in more detail below.

       Caution: If the handle is rotated quickly while the magnitude is set at X100 or X1K the tool will move at a rapid feed rate and a crash could occur!

       Teach

      This button activates the Teach-in Jog or Teach-in Handle mode. When this mode is used, the movements of the axes are recorded while in either Jog or Handle mode. Machine positions along the X, Y, and Z axes obtained by this manual operation are stored in memory as a program position and are used to create a program. These movements can then be executed just as with any program. Consult the manufacturer operator’s manual for detailed descriptions on its proper use. Not all controls have this feature.

       Offset Mesur-Offset Measurment

      When this button is pressed, the OFFSET MEASURE mode is selected and the position of the tool in relation to the coordinate system is written into the tool or work offset for the active axis.

      SPEED/MULTIPLY

      When INC JOG is selected from the Operation Mode buttons, the incremental step selected by the Speed/Multiply buttons determines the magnitude of the displacement along the chosen axis in the selected direction. When one of these buttons is pressed and released, the movement will be as follows:

      X1 = a movement of .0001 inch or .0025 millimeters (mm)

      X10 = a movement of .001 inch or .0254 mm

      X100 = a movement of .010 inch or .254 mm

      X1K = a movement of .100 inch or 2.54 mm

      The buttons used to select the axis and the direction of movement are located on the mid to upper right part of the operator panel as shown in Figure 1 for this controller.

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      Figure 12 Speed/Multiply Buttons

      For example, to displace the tool along the X axis in a positive direction by the value of .010 inch, follow these steps:

      • Press the INC JOG button.

      • Press the X100 button.

      • Press the button X once.

      Each time the button is pressed, a displacement of the selected value results.

      If the JOG mode is selected when one of these buttons are activated and the selected axis button is pressed and held in, the movement will occur at feed as indicated by LOW, MEDL, MED, MEDH or HIGH. The operator can also use the % Traverse Feed override dial to further control this feed rate.

      When the MPG Operation mode is selected, the incremental step selected by the Speed/Multiply buttons determines the magnitude of the movement along the chosen axis in the selected direction.

      Each button setting corresponds with the scale of the Handle. One full revolution of the Handle (360°) corresponds to 100 units on the scale. On the button X1 the X means “times” the minimum increment.

      When the button is pressed for:

      X1, turning the handle by one unit corresponds to the movement of .0001 inch or .0025 mm.

      X10, turning the handle by one unit corresponds to the movement of .001 inch or .0254 mm.

      X100, turning the wheel by one unit corresponds to the movement of .01 inch or .254 mm.

      X 1K, turning the wheel by one unit corresponds to the movement of .100 inch or 2.54 mm.

      Usually, X1 is used when you are precisely dialing-in the zero of the workpiece and when you are determining the tool length offset.

      In manual control, you must also use the AXIS/DIRECTION buttons to determine the axis of displacement.

      For example: if you need to move the machine table, with respect to the tool by 1.00” along the X axis in a positive direction, follow these steps:

      • Press MPG Operation mode button.

      • Press the AXIS/DIRECTION button X+

      • Press the SPEED/MULTIPLY button X10.

      Turn the handle one full revolution (100 units) and then check the value of the displacement on the screen. It should indicate a movement of 1.00”.

       LOW

       X1

      The button, LOW indicates feed rate at a LOW speed while in the JOG Operation mode. The button, labeled as LOW X1 indicates that turning the handle by one unit corresponds to the displacement of .0001 inch or .0025 mm while in the MPG Operation mode.

       MEDL

       X10

      The button, MEDL indicates feed rate at a MEDIUM LOW speed while in the JOG Operation mode. The button, labeled as MEDL X10 indicates that turning the handle by one unit corresponds to the displacement of .001 inch or .0254 mm while in the MPG Operation mode.

       MED X100

      The button, MED indicates feed rate at a MEDIUM speed while in the JOG Operation mode. The button, labeled as MED X100 indicates that turning the handle by one unit corresponds to the displacement of .01 inch or .254 mm while in the MPG Operation mode.

       MEDH

       X1K

      The button, MEDH indicates feed rate at a MEDIUM HIGH speed while in the JOG Operation mode. The button, labeled as MEDH X 1K indicates that turning the handle by one unit corresponds to the displacement of .100 inch or 2.54 mm while in the MPG Operation mode.

       HIGH

      This

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