CNC turning machining example

Although the functions of different CNC systems and CNC lathes are somewhat different, there are some changes in the operation panel of CNC lathes, but the basic functions and basic forms of the operation panels are similar. The following describes the operation panel of the HCNC-1T turning CNC system with the simple CNC lathe CJK6032, as shown in Figure 3-30.
The functions of the buttons on the operation panel are as follows:
(1) After the power switch is closed, turn on the power switch on the operation panel with the key to turn on the CNC power. Also use the key to disconnect the CNC power.
(2) Emergency stop button During the operation of the machine tool, when an emergency situation occurs, press the emergency stop button, the servo feed and spindle operation will stop working immediately, and the CNC will enter the emergency stop state. When the emergency stop is to be released, it must be lifted in the direction of the arrow of the emergency stop button to release.
(3) Overtravel release button When an overtravel occurs on an axis, when exiting the overtravel condition, the overtravel release button must be pressed in the manual mode, and the coordinate direction direction button (+X, -X) is pressed at the same time. , +Z or -Z) reverse direction button to release the overtravel status.
(4) Working mode Select the band switch to select the working mode of the system through the working mode selection switch, including: automatic, single-segment, manual, stepping, zero return and other five working modes.
(5) Automatic mode When the working mode selection band switch is placed in this working mode, the machine tool control is automatically completed by the CNC, that is, it is automatically controlled by the NC program.
(6) Single-segment mode When the mode selection band switch is placed in the working mode, the program control will be carried out step by step, that is, after the machine is stopped for a period of time, press the cycle start button again to execute the next block, and after the execution is finished, Stop again. This method is generally used when debugging a program or trying to cut a workpiece.
(7) Manual/jog mode When the mode selection band switch is placed in this mode, press +X, -X, +Z or -Z, the machine will jog in the corresponding axial multiplication rate, release The button decelerates to a stop. When pressing +X, -X, +Z or -Z, press the quick-shift button at the same time, the jog speed is faster. This method is mainly performed when clamping, adjusting the workpiece, setting the tool parameters and other preparation work.
(8) Stepping mode When the mode switch is selected in the working mode, press +X, -X, +Z or -Z, and the machine will multiply the feedrate override in the corresponding axial direction by a multiple of the pulse equivalent. , release the button to stop. This method is mainly used when fine adjustment of the machine or precision setting.
(9) Zero return mode When the mode switch is selected in this mode, press +X, -X, +Z or -Z, and the machine will return to zero in the corresponding axis. Under normal circumstances, after the system is powered on or after exiting the CNC system, the machine axes must first be zeroed. During the zero return process, actions that move the axes (such as jog) are not allowed; all axes can be allowed. At the same time, the zero return operation is performed.
(10) Feedrate override In the automatic, jog and step mode, when the feedrate is too high, the feedrate override switch on the operation panel can be used to adjust the actual feedrate of the machine. This switch can provide 5%. , 10%, 30%, 50%, 70% and 100% six-tone revision ratio.
(11) Tool position selection After selecting the corresponding tool, press the “tool holder open/stop” button to manually transfer the tool selected by the user to the cutting position.
(12) Start of automatic start of cycle start.
(13) Feed keeps automatic operation paused. During the automatic operation mode, press the “Feed Hold” button, the machine motion axis decelerates to a stop, the execution of the program is suspended, and the tool and machine axis stop running. During the pause, the button indicator lights.
In the pause state, press the “Cycle Start” button again, the system will restart and continue to run from the paused position.
(14) Before the automatic operation starts, press the “machine lock” button, the recirculation starts, the coordinate position information changes, but the X-axis and Z-axis directions of the tool holder are not allowed to move (the tool holder can be indexed) . This function is used to verify the program.
(15) Coolant on/off Press this switch to turn on the coolant; when it is released, the coolant is off.
(16) Manual button for spindle forward/spindle stop/spindle reversal/spindle jog spindle rotation control. Spindle jog is generally used when the spindle speed is mechanically shifted after the gear is tested or the spindle is commissioned.
As for the specific operation of HCNC-1T turning CNC system with simple CNC lathe CJK6032, please refer to its instruction manual.
[Example 3-8] It is known that the blank is a bar of Φ30mm and the material is 45 steel. The CNC is turned into a positive cone as shown in Figure 3-31.
1. According to the requirements of the part pattern and the blank condition, the process plan and the machining route are determined for the short-axis parts, the axial line is the process reference, and the rough finishing is completed by the three-claw self-centering chuck once.
The sequence of steps is as follows:
2. Selecting machine tools According to the requirements of the part drawings, the MJ-50 CNC horizontal lathe can be used.
3. Select the tool according to the processing requirements, select two tools, T01 is 90° rough turning tool, T02 is 90° precision turning tool. At the same time, the two knives are mounted on the automatic tool changer, and both are good knives, and their tool offset values ​​are input into the corresponding tool parameters.
4. Determining the amount of cutting The specific amount of cutting should be determined according to the performance of the machine, the relevant manual and the actual experience. The setting is divided into three passes. The first two backs are ap=2mm, and the last back is ap=1mm.
5. Determine the workpiece coordinate system to determine the intersection point of the right end of the workpiece at the intersection with the axis line O as the workpiece origin, and establish the X0Z workpiece coordinate system, as shown in Figure 3-31.
6. The program is programmed into a program list according to the instruction code and block format specified by the machine. The machining procedure of the workpiece is as follows:
[Example 3-9] The parts shown in Figure 3-32(a) are finished on the CK7815 CNC lathe. The Φ85mm outer cylindrical surface in the figure is not machined. Try to compile its finishing program.
1. According to the requirements of the parts drawing, the machining process plan is determined according to the processing principle of the first and second parts.
2. Select the tool and draw the tool layout. Three tools are required according to the machining requirements. The tool layout is shown in Figure 3-32(b). T01 cutter outer circle, T02 knife slot, T03 cutter thread. For the tool setting, use the T-knife as the reference tool to measure the deviation of the other two tools with respect to the reference tool, and input their tool offset values ​​into the tool-biasing unit of the corresponding tool.
In order to avoid collision between the tool and the machine tool, workpiece and fixture during tool change, the tool change point should be selected correctly. In this example, the tool change point is selected as A (X200, Z350) point.
3. Select the cutting amount and the cutting amount is shown in Table 3-4.

Cutting surface	Cutting amount
	Spindle speed S/r.min-1	Feed rate f/mm.r-1
Outside the car	630	0.15
Grooving	315	0.16
Thread	200	1.50

4. Programming CNC finishing program The machine can be programmed with absolute value and incremental value. The absolute value is X and Z address, the incremental value is U and W address, and the decimal point is programmed. The machining procedure is as follows: