Programming of CNC Machines. Ken Evans
needed, but you would like to keep this information for future use, then place the block skip symbol (/) at the beginning of each such block. The BLOCK DELET button is located on the control panel. If it is activated, then information contained in the blocks that are preceded by the symbol (/) will not be executed.
Example:
N100G01X2.810Y3.256
/N105X3.253Y2.864
/N110X3.800
(Blocks N105 and N110 will be skipped)
Notes: The symbol (/) should be placed at the beginning of the block. If it is not, then all the information contained in the block preceding the symbol (/) will be executed, while the information following this symbol will be omitted.
If the BLOCK DELET is in the OFF condition, all blocks, regardless of the symbol (/), will be executed.
When transferring the program to punched tape or external computer, all program information, regardless of symbol (/), is transferred.
Opt Stop-Optional Stop
When this button is pressed, the OPTIONAL STOP mode is active. The OPTIONAL STOP function interrupts the automatic cycle of the machine if the program word M01 appears in the program. Quite often, function M01 is placed in the program after the work of a particular tool is completed or before a tool change. This enables the operator to perform routine measurements directly on the machine and, if necessary, make adjustments and then rerun the same tool to correct inaccuracies.
Dry Run
By pressing the DRY RUN button during automatic cycle, all of the rapid and work feeds are changed to the rapid traverse feed set in the parameters instead of the programmed feed. Consult the manufacturer manual for specific directions on the use of this function.
DRY RUN is also used to check a new program on the machine without any work actually being performed by the tool. This is particularly useful on programs with long cycle times so the operator can progress through the program more quickly.
Caution: When using this function, it is NOT intended for metal cutting.
Prg Test-Program Test
This function is also known as MACHINE LOCK. Activating this mode inhibits axis movement on all of the axes. This button is used to check a new program on the machine through the controller. All movements of the tool are locked, while a program check is run on the computer and displayed on the screen. The operator can observe the position display on the screen and if any program errors are encountered, an alarm will be displayed. This function is especially useful for checking very large programs requiring a long cycle time to complete. This test is normally the first in a series (Program Test, Dry Run and Single Block) of preliminary actions to be executed before full auto cycle mode is attempted. For any program test, all offsets should be set first.
Axis Inhbt-Axis Inhibit
This function is identical to MACHINE LOCK for all axes. Activating this mode inhibits axis movement on all of the axes. A common situation would be to inhibit the axes to allow for internal checking of the program. Some controllers have additional buttons or switches that enable inhibiting of only one axis at a time. This function is especially useful when inhibiting the Z axis so that all X, Y movements can still be observed.
Figure 9 Execution Buttons
EXECUTION
These three buttons are related to automatic operation of the machine. The first button starts, the second temporarily stops automatic operation and the last key merely indicates when a program stop is encountered. Their specific functions are described below:
Cycle Start
The CYCLE START button is used to start automatic operation. Use this button in order to begin the execution of a program from memory. When the CYCLE START button is pressed, the LED located above this button goes on and the active program will be executed to the end.
Cycle Stop (Feed Hold)
Pressing the CYCLE STOP button during automatic operation will halt all feed movements of the machine. It will not stop the spindle r/min or affect the execution of tool changes on some machines. When the CYCLE STOP button is pressed, the LED located on the button goes on, and the LED located on the CYCLE START button goes off. When the CYCLE STOP button is pressed, all feeds are temporarily stopped; however, the spindle rotation is not affected. This button is used when minor problems are encountered, such as coolant flow direction or when checking DISTANCE-TO-GO during setup. When the problem is remedied, press CYCLE START again to resume automatic cycle operation. It is not recommended using this button to interrupt a cut because the spindle does not stop and damage to the tool or part may occur. When pressed during the execution of the tapping or threading cycle, CYCLE STOP will take effect after the thread pass or the tap is withdrawn. If the tap breaks during the tapping cycle, the only way to stop the machine is by pressing the RESET button on the controller or the EMERGENCY STOP button.
Prg Stop-Program Stop
When a Program Stop is commanded in the program by the program word M00, automatic operation is stopped and the LED on this button is turned on. This button does not have an ON/OFF function that affects the program stop condition. It is merely an LED indicator lamp to indicate when a program stop condition is active.
Figure 10 Operation Buttons
OPERATION
The keys in the Operation section of the control are used for manual operation of the machine during setup and initial startup. Their specific functions are described below:
Home
Pressing this button on and then pressing the X or Z (X, Y or Z for Machining Centers), buttons causes the machine to return to the Machine Zero position for each axis in relation to the machine coordinate system.
Jog
Pressing the JOG button activates a manual feed mode that allows the selection of manual feed movements along single axes X or Z (X, Y, or Z for machining centers). With the button activated, use the Axis/Direction buttons and the Speed/Multiply buttons to move the desired axis at the chosen feed rate (in/min). On some controls Speed/Multiply is a rotary type switch that activates this function.
INC Jog
Press this button (Incremental JOG) to activate the JOG mode in Incremental steps at feed as per selection using the Speed/Multiply buttons.
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.
Figure 11 Manual Pulse Generator (MPG) Handle
To set the