Exercise 1 Milling a Part with the Lab-Volt CNC Mill EXERCISE OBJECTIVE When you have completed this exercise, you will be able to engrave text on square pieces of stock, using the Lab-Volt CNC Mill, model 5600, and the Lab-Volt CNC Mill Software. DISCUSSION Figure 1-1 shows the part you will create in this exercise, using the Lab-Volt CNC Mill, Model 5600. The part is created by engraving the following text on a square piece of stock: Lab-Volt CIM. Figure 1-1. Milled part. The part program used to create the part is shown in Table 1-1, in both inch and millimeter units. This program is intended to be opened in the Lab-Volt CNC Mill Software. 1-1
The following G codes are used to perform the geometric functions required to engrave the text. G00 (RAPID): rapid linear interpolation; G01 (MOVE): feed linear interpolation; G02 (ARC.CW): clockwise arc; G03 (ARC.CCW); counterclockwise arc; G05 (ARC); circular arc. CNC PART PROGRAM USED TO ENGRAVE "Lab-Volt CIM": 39468_EX1_**.m5 LINE NUMBER MILLIMETERS (mm) INCHES (in) 1 G21 G20 2 G90 G90 3 G00 Z70 G00 Z2.75 4 X3.5 X.14 5 Y44 Y1.73 6 Z5 Z.2 7 M03 S2800 M03 S2800 8 G04 50 G04 50 9 F500 F20 10 G01 Z-1 F250 G01 Z-.04 F10 11 Y38 Y1.5 12 X7.5 X.3 13 G00 Z5 G00 Z.2 14 X13.3 X.525 15 G01 Z-1 F250 G01 Z-.04 F10 16 Y40 Y1.575 17 G03 G03 18 X11.3 Y40 X.45 Y1.575 19 G05 G05 20 G01 Y42 G01 Y1.65 21 G00 Z5 G00 Z.2 22 X15.7 Y38 X.62 Y1.5 23 G01 Z-1 F250 G01 Z-.04 F10 24 Y40 Y1.575 Table 1-1. Part program in inch or millimeter units. 1-2
CNC PART PROGRAM USED TO ENGRAVE "Lab-Volt CIM": 39468_EX1_**.m5 LINE NUMBER MILLIMETERS (mm) INCHES (in) 25 G02 G02 26 X17.7 Y40 X.695 Y1.575 27 G05 G05 28 G01 Y44 G01 Y1.73 29 G00 Z5 G00 Z.2 30 X22 Y40.5 X.87 Y1.6 31 G01 Z-1 F250 G01 Z-.04 F10 32 X26 X1.02 33 G00 Z5 G00 Z.2 34 X28 Y44 X1.1 Y1.73 35 G01 Z-1 F250 G01 Z-.04 F10 36 Y41 Y1.62 37 X30 Y38 X1.18 Y1.5 38 X32 Y41 X1.26 Y1.62 39 Y44 Y1.73 40 G00 Z5 G00 Z.2 41 X34 Y40 X1.34 Y1.575 42 G01 Z-1 F250 G01 Z-.04 F10 43 G02 G02 44 X36 Y40 X1.415 Y1.575 45 G05 G05 46 G00 Z5 G00 Z.2 47 X41 Y38 X1.62 Y1.5 48 G01 Z-1 F250 G01 Z-.04 F10 49 Y44 Y1.73 50 G00 Z5 G00 Z.2 51 X45.6 X1.8 52 G01 Z-1 F250 G01 Z-.04 F10 53 Y38 Y1.5 Table 1-1. Part program in inch or millimeter units (cont'd). 1-3
CNC PART PROGRAM USED TO ENGRAVE "Lab-Volt CIM": 39468_EX1_**.m5 LINE NUMBER MILLIMETERS (mm) INCHES (in) 54 G00 Z5 G00 Z.2 55 X43.6 Y42 X1.72 Y1.65 56 G01 Z-1 F250 G01 Z-.04 F10 57 X47.6 X1.88 58 G00 Z5 G00 Z.2 59 X18.3 Y28 X.72 Y1.1 60 G01 Z-1 F250 G01 Z-.04 F10 61 X7 X.28 62 Y11 Y.43 63 X18.3 X.72 64 G00 Z5 G00 Z.2 65 X25 X1 66 G01 Z-1 F250 G01 Z-.04 F10 67 Y28 Y1.1 68 G00 Z5 G00 Z.2 69 X31.5 Y11 X1.24 Y.43 70 G01 Z-1 F250 G01 Z-.04 F10 71 Y28 Y1.1 72 X37.3 Y19.5 X1.47 Y.77 73 X43 Y28 X1.7 Y1.1 74 Y11 Y.43 75 G00 Z5 G00 Z.2 76 M05 M05 77 G00 Z8 G00 Z.3 78 Z25 Z1 79 X0 X0 80 Y50.8 Y2 81 M30 M30 Table 1-1. Part program in inch or millimeter units (cont'd). 1-4
Prerequisites Before you begin the practical section of the exercise, make sure the following requirements are met. 1. You must have gone through Section 2, "Operation", of the Lab-Volt Quick-Start Guide "Familiarization with the CNC Mill" (part number 36783-E), in order to know how to operate the mill control panel, change the cutting tool and collet, mount the block to be milled, set the program reference zero (PRZ), prepare the mill to accept a part (*.m5) program, download the program, and mill the part. 2. You must be familiar with the CNC Mill Software. To obtain detailed information about this software, refer to the Lab-Volt User Guide "CNC Mill Software" (part number 36189-E). Section 4 of this guide, "Tutorial Exercise", describes the steps used to create and edit part programs with the software. Procedure summary In this exercise, you will mill the part described in the DISCUSSION section of this exercise. EQUIPMENT REQUIRED Lab-Volt CNC Mill, Model 5600; Lab-Volt CNC Mill Software, Model 5660; Two-flute end mill, 1.588-mm (0.0625-in) diameter; Pieces of wax [50.8-mm (2-in) wide, 50.8-mm (2-in) long, 12.7-mm (0.5-in) thick]. PROCEDURE Setting Up the System G 1. On the CNC mill, install the following cutting tool, if it has not been installed yet: a 1.588 mm (0.0625-in) two-flute end mill with the proper collet. G 2. Load a piece of stock in the vise of the mill: a 50.8-mm (2-in) wide, 50.8-mm (2-in) long, 12.7-mm (0.5-in) thick block of wax. Note: If a pneumatic vise, Lab-Volt Model 5616, is currently installed on the CNC Mill, you can refer to procedural step 9 of Exercise 3 for the steps to follow in order to load the stock in the vise. Note: The part program you will run to mill parts has been written specifically for wax. When another type of material is used, several program lines must be modified, in order to correct the spindle speed, the feed rates, and the depth of cut. 1-5
Setting the Programmed Reference Zero (PRZ) G 3. On the mill, set the programmed reference zero (PRZ) by using the steps below. The desired location for the PRZ is the upper front left corner of the block, as Figure 1-2 shows. Note: The steps below are used to coarsely set the programmed reference zero (PRZ). To set the PRZ more accurately, for example when a high precision is required on the machined part, follow the extended procedure provided in the section "Set the Programmed Reference Zero (PRZ)" of the Lab-Volt Quick-Start Guide "Familiarization with the CNC Mill", part number 36783-E. a. On the mill control panel, select Manual from the main menu of the control panel to access the Manual menu. b. Using the +X and -X keys, and the +Y and -Y keys, position the center of the cutting tool right over the upper front-left corner of the block, as Figure 1-2 (a) and (b) show. Figure 1-2. Position the center of the cutting tool right over the upper front-left corner of the block. 1-6
c. Leave the center of the tool right over the upper front-left corner of the block. Using the +Z and -Z keys, position the end of the tool so that it is just touching the block, as Figure 1-2 (c) shows. Press Zero twice, which will set the X, Y, and Z coordinates of the PRZ to the current position of the cutting tool. d. Using the +Z key, raise the headstock above the block, then press ESC to return to the Main menu of the mill control panel. Preparing the Mill for Part Program Download G 4. Prepare the mill for part program download, so that it is ready to accept a program from the computer used to run the CNC Mill Software. (To do so, select Remote Serial from the Main menu of the mill control panel. The mill control panel now indicates: "READY TO DOWNLOAD".) Opening the Part Program in the CNC Mill Software G 5. Connect a serial (COM) port of the computer used to run the CNC Mill Software to the serial port at the back of the mill. On the computer, run the CNC Mill software. G 6. In the CNC Mill Software, open file 39468_EX1_**.m5 [in either millimeters (mm) or inches (in), according to your preference]. The Line Editor window will appear, displaying the part program in ISO G and M codes. Make sure this program is the same as that listed in Table 1-1 of the DISCUSSION section. Note: The coordinate values are in absolute (measured from the programmed reference zero, or PRZ.) Setting the Home Position of the Mill Tool Table G 7. In the CNC Mill Software, verify the setting of the Home position of the cutting tool: in the File menu, select Info..., which will bring up the Program Information... dialog box. In this box, make sure that the Absolute Home Position is set to X = 0 mm (0 in), Y = 0 mm (0 in), and Z = 25.4 mm (1 in), as Figure 1-3 shows. The Part Reference Zero Position should be set as follows: X : 0 mm (0 in) X+: 50.8 mm (2 in) Y : 0 mm (0 in) Y+: 50.8 mm (2 in) Z : -12.7 mm (-0.5 in) Z+: 0 mm (0 in) 1-7
Click on the OK button to save your settings and close the Program Information... dialog box. Figure 1-3. Setting the home position of the cutting tool. G 8. In the CNC Mill Software, set the Mill Tool Table according to the type of tool used for part program 39468_EX1_**.m5. In the Options menu, select Mill Tool Table..., which will bring up the Tool Table tabbed window. a. Make sure the Tool Number field is set to 1. b. Make sure the Nose Type drop-down list is set to End Mill. c. Set the Bit Diameter field to 1.5875 mm (0.0625 in). d. Make sure the Bit Offset (Z-Axis field) is set to 0.0000 mm (0.0000 in). e. Click on Save to save your settings and close the Mill Tool Table dialog box. 1-8
Figure 1-4. Setting the Tool Table. Emulating the Part Program G 9. In the CNC Mill Software, emulate program 39468_EX1_**.m5 to see the rendering process and the finished part, prior to the download to the mill. a. First, set the rendering preferences of the Emulator: in the Options menu of the main screen, select Rendering... This will bring up the Rendering tabbed window, shown in Figure 1-5. Make sure to set the Curve Smoothness field to 100. In the Tool Rendering section, make sure the Camera Follows Tool box is unchecked, and that the Show Tool Path box is checked. Click on the Save button to save the settings and close the Rendering window. 1-9
Figure 1-5. Rendering tabbed window. b. In the Mill menu of the main screen, select Emulate. Once the program 39468_EX1_**.m5 has been checked for errors, the Compiling... dialog box will appear, indicating "Successful compile". Click on the OK button, which will close this box and bring up the Mill 3D Emulator window. c. In the Mill 3D Emulator window, make sure the Mouse Rotate button of the View palette is selected. Position the mouse pointer over the stock view and, while holding down the left mouse button, rotate the stock in order to obtain a 3D view, as Figure 1-6 shows, then release the mouse button. 1-10
Figure 1-6. Line Editor and Mill 3D Emulator window. d. In the Mill 3D Emulator window, click on the Start Simulation button of the Control palette, which will start the part rendering process. Once the rendering process is completed, you can see the finished part in the Emulator window, as Figure 1-7 shows. The Time field at the bottom of the window indicates the approximate time required to mill the part. e. Close the Mill 3D Emulator window. 1-11
Figure 1-7. Finished part with tool paths displayed. Verifying Communications Configurations G 10. In the CNC Mill Software, verify that the computer is configured for proper communications with the mill: in the Options menu, select Machine Setup, which will bring up the Machine Setup tabbed window. a. In the Serial Port drop-down list, make sure the proper computer's COM port is selected (COM port through which the computer is connected to the mill). b. Do not modify the setting of the fields and boxes in the CIM Cell section (that is, leave the Enable CIM Mode check box unchecked, and the CIM Repeat Count field set to 1). c. Click on Save to close the Machine Setup dialog box. 1-12
Note: Once the CNC Mill Software is configured for proper communication with the mill, the Remote machine settings will remain until you change them. However, you should always check them before downloading a part program to the mill. Downloading the Part Program G 11. Download the program 39468_EX1_**.m5 to the mill: in the Mill menu of the CNC Mill Software, select Download Program via Serial Port, which will bring up the Download Program from Serial Port... dialog box. Click on the Download button in this box. The control panel of the mill should indicate that the download process is taking place, if proper communication exists between the computer and the mill. Once the download is completed, the Download Program via Serial Port dialog box indicates Closing serial port, and Successful download. Click on OK to close this box. Milling the Part G 12. The mill control panel now indicates that the program download is completed. Press ENTER on this panel to start the execution of the part program by the mill. CAUTION! If an emergency condition occurs during the miling of the part, press the emergency stop button on the mill control panel (symbolized by a hand pressing a button's knob). The ERROR INDICATOR/PAUSE button of this panel will start flashing on and off, while the mill control panel will indicate "ERROR CONDITION, EMERGENCY STOP". Thereafter, use the steps below to return the system to normal operation: On the mill control panel, press ESC to abort the execution of the program. The mill control panel now indicates: "HOW TO RETURN?" Press ESC to stay there. The mill control panel now indicates: "EMERGENCY STOP, CORRECT ERROR CONDITION". Release the emergency stop button with the required key. On the mill control panel, press ESC to abort and return to the Main menu. Select Manual in the Main menu and move the tool to a safe position. Correct the problem. Once the problem has been corrected, you can run the program again by selecting Remote Serial from the Main menu, and then pressing ENTER to run the program (which remains in memory as long as the CNC Mill as not been turned off.) 1-13
Once the part program has been executed, it can be run again simply by pressing the ENTER key on the mill control panel from the Remote Serial menu. It is not necessary to download the program to the mill again until the mill is turned off. G 13. Turn off the CNC Mill. CONCLUSION In this exercise, you milled parts with the CNC Mill, using the CNC Mill Software. The part program used G codes to perform the geometric functions required to engrave the text, including G00 (RAPID), G01 (MOVE), G02 (ARC.CW), G03 (ARC.CCW), and G05 (ARC). The engraved text was: "Lab-Volt CIM". REVIEW QUESTIONS 1. What is the G code used to perform counterclockwise arcs? 2. What is the G code used to perform clockwise arcs? 3. The program you used in this exercise was written specifically to mill wax. If another type of material was used, which program lines might need modification? 4. The reference point from which the CNC program will make all moves, and that must be imperatively set on the CNC Mill before running a program is called the 5. What is the effect of pressing each of the following keys on the control panel of the CNC Mill? Z key +Y key +X key 1-14