Programming of CNC Machines. Ken Evans
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Figure 2-21 PC Function Keys Courtesy FANUC FA America
Special
The Special Key allows selection of two keys simultaneously from within the NC Guide i software (PC version only). It is used for PC operations where pressing of multiple keys is required.
• Press the Special key.
• Press the required multiple keys in any order. The command will be executed upon final key entry.
Figure 2-22 ABC/abc Key Courtesy FANUC FA America
Figure 2-23 SPECIAL Key Courtesy FANUC FA America
OPERATIONS PERFORMED AT THE CNC CONTROL
The following explanations are for operations considered routine for users of CNC machine tools and are given in their sequence of use. Please note that these procedures are specific to the type of controller depicted here (Fanuc series 0i). The procedures for another type of control may be similar. Be sure to consult the manufacturer manuals specific to your machine tool operation and control panel.
The Machine is Turned On and Homed (Machine Zero)
Turn on the main power switch, and then press the ON Power button on the controller. Most modern machine tools will automatically start-up in the REF/ZERO RETURN mode. This means that before any automatic or manual operation may begin, you must Home the machine first.
If the LED above the REF button in the operation section of the Operator Panel is not lit, press it now to activate the mode.
Using the Axis/Direction keys, press the direction necessary to HOME the machine. Note that many machine tools will have LEDs for each axis that are lit to indicate when that axis is HOMED.
At machine start-up, a common screen displayed is ACTUAL POSITION (ABSOLUTE). If it is not displayed, press the function key labeled POS, then the soft-key ABSOLUTE. The displayed coordinate values represent the relationship between the Workpiece Zero and the Machine Zero (HOME). When the machine is HOME, press the soft-key OPRT, then ORIGIN, and then ALL AXIS to zero each of the coordinate axes.
By pressing the soft keys, you can activate other display screens. For instance, when you press the button ABSOLUTE (which corresponds to position), the digital counter appears on the screen for the X, Y and Z axes, which is the absolute coordinate system for a given workpiece (for turning centers, X and Z will be displayed). The position (POS) function is assigned four display screens and can be found by pressing the soft keys labeled ABSOLUTE, RELATIVE, ALL, and (OPRT). The first screen corresponds to a position change in the ABSOLUTE (ABS) system for X, Y, and Z, as illustrated in Figure 2-24. The second screen RELATIVE (REL) corresponds to position changes in the incremental system for milling machines X, Y, and Z (U and W for turning centers). The third, ALL, gives representation of all four of the displays simultaneously on one screen, as shown in Figure 2-25.
The values listed in the readout for MACHINE represent the distance from Machine Home position.
The DISTANCE TO GO readout is the most significant part of the third display. The coordinates in this quarter of the screen display correspond to the path that will be followed by the tool in order to complete the execution of a given block of information while under automatic operation.
Figure 2-24 Actual Position (Absolute) Screen Courtesy FANUC FA America
Figure 2-25 Actual Position, ALL Screen Courtesy FANUC FA America
Example
N20 G00 Z0.0
N22 G01 Z–12.00 F.015
When block N22 is first read by the control, the value Z–12.000 will appear under the DISTANCE TO GO readout in the upper right corner of the screen. After moving a distance of 1 inch, the value of coordinate Z changes to Z–11.000, and so on. The other displays, ABSOLUTE and RELATIVE, correspond to the first two display screens, but this time they are smaller so that all four displays may fit on one screen. All of the displays may be changed to read in millimeters, with respect to Machine Zero, by changing a machine parameter or by using a G-Code in the program.
The codes listed in the lower left corner of the display pictured in Figures 2-24 and 2-25 are the default G-Codes that are active upon startup of the machine. They are also reinstated by pressing the RESET key.
A Program is Loaded from CNC Memory
The program may be in the program directory, but not activated for automatic operation as shown in Figure 2-26. Follow these steps to activate a program.
1. Press the EDIT button to enter the EDIT mode.
2. Press the PROG function button.
3. Press the DIR soft key.
4. Key in the desired program number from the list. Soft key availability changes to include O SRH.
5. Press the O SRH soft key. The program is now activated.
6. Press the AUTO cycle key to execute the program.
Figure 2-26 Program Folder Screen Courtesy FANUC FA America
A Program is Loaded from an Offline Location
Examples of offline locations include memory cards (PCMIA) and USB drives. Be sure that the output device is ready.
1. Press the EDIT button.
2. Press the PROG function key.
3. Press the DIR soft key.
4. Press the OPRT soft key.
5. Press the DEVICE CHANGE soft key.
6. Select the MEMORY CARD soft key to see available the files or MEM CARD for those on USB.
Select the desired file from the list by keying in the program number and then press the EXEC soft key to activate.
For network drives connected via the Ethernet, if available:
1. Press the EDIT button.
2. Press the PROG function key.
3. Press the DIR soft key.
4. Press the OPRT soft key.
5. Press the DEVICE CHANGE soft key.
6. Select the EMBED ETHER soft key to see available the files from the EMBEDDED ETHERNET HOST FILE LIST.
7. Press the F INPUT soft key.
8. Key in the desired program file name or select desired file from the list by using the cursor move keys.
9. Press the F NAME soft key.
10. Press the EXEC soft key to activate.
A Program Folder is Saved from CNC Memory
1. Press the EDIT button on the operator panel to enter the EDIT mode.
2. Press PROG function key.