1. Unit 9 NC Machine Operation数控机床操作

2. Lesson 1 The Machine Operation Panel 数控机床操作面板
A control panel is shown in Figure 8-1
Figure 8—1 Control panel

3. Lesson 1 The Machine Operation Panel
1. Emergency stop急停
The “Emergency stop” button is red and located in the lower left corner of the control panel. If this button is pressed, the feed and rotation of the tool is stopped and the control system of the computer is turned off. The “Emergency stop” button is only used in special situations. Some of these are overloading of the machine, a loose machined part or incorrect data in the program that are causing a collision between the tool and the work-piece. To reset the “Emergency stop” button, push it in and turn it clockwise. Then you can turn the machine on, zero it, and eliminate the cause that forced the use of the “emergency stop” button. Additionally, check whether any alarm signs appeared on the screen or whether the machine stopped during the execution of cycle corresponding to a tool change or a table change. If such is the case, then repeat the same command with the switch positioned on the MDI (manual data input) to make sure that the cycle has been completed.

4. Lesson 1 The Machine Operation Panel
2. Mode select 模式选择
Use the switch on the panel to decide the operation mode. The position of the switch determines whether the machine utilizes the computer or the manual control.
3. Edit 编辑
Positioning the switch in the “edit” mode enable you to:
1)．Enter the program to machine memory;
2)．Enter any changes to the program;
3)．Transfer data from the program to a tape
4)．Check the memory storage capacity
4. Memory 存储
Positioning the switch in the “memory” mode enables the NC commands stored in the memory to be executed.

5. Lesson 1 The Machine Operation Panel
5. Manual data input (MDI) 人工数据输入
Positioning the switch in the MDI mode enables the automatic control of the machine. Use information entered in the form of blocks without interfering with the basic program. It corresponds to single moves (milling surface, drilling hole), descriptions of which need not to be entered to memory storage. MDI can also be used during the execution of the program. For example, suppose you have omitted the S350 M03 in the program. In order to correct this omission, turn on the “single block” switch and position selector switch to the MDI mode. Using MDI, you can enter the command S350 and M03. Enter this command through “input” and “start”. The selector switch is positioned in the “Memory” mode to continue execution of the program from memory.

6. Lesson 1 The Machine Operation Panel
6. Handle 手动
Positioning the switch in the “handle” mode allows for the manual control of the movement of the table with the use of the hand wheel, along one of the three axes: X Y, or Z. By turning the hand wheel clockwise, you can displace the tool in a positive direction with respect to the position of the coordinate system. By turning the hand wheel counterclockwise, the tool is displaced in a negative direction with respect to the position of the coordinate system. The shaft of hand wheel contains 360 notches, each of which corresponds to 10 of rotation. Turning the hand wheel, you can feel the displacement from one notch to the next. Handling the machine manually, use the additional speed switch, which can change the value of displacement equal to one skip on the scale of the hand wheel. One full revolution of the hand wheel (3600) corresponds to 100 units on the scale.

7. Lesson 1 The Machine Operation Panel
7. Jog 点动进给
Setting the selector switch in the “jog” mode allows the selection of manual monotonous feed along the X Y and Z- axes .with the selector switch in the “jog” mode, use the axis button, as well as the “jog feed rate” switch.
8. Cycle start 循环启动
Use “cycle start” button during the execution of the program from memory or tape. When the “cycle start” button is pressed the control lamp located above this button goes on.
9. Feed hold 进给保持
When the “feed hold” button is pressed the control lamp above the button goes on, and the control lamp located above the “cycle system” butting goes off. When the “feed hold” button is pressed, all feed are interrupted. However, the rotations are not affected. During the execution of the threading cycle, “feed hold” comes into effect after the tap is withdrawn. If the tap breaks during the threading cycle, the only way to stop the machine is by pressing the “emergency stop” button.

8. Lesson 1 The Machine Operation Panel
10. Single block 单程序段
The execution of a single block of information is initiated by turning the switch “on”. Each time the “cycle start” button is pressed, only one block of information will be executed. This switch can also be used if you intend to check the operation of a new program on the machine or if the momentary interrupt of a machine’s work is necessary.
11. Dry run 空运行
By turning this switch ON, all the rapid feed and work feeds are changed to one chosen feed. In order to do this, use the “jog feed rate” switch. “dry run” is also used to check a new program on the machine without any work actually being performed by the tool.
12. Reference return 零点返回
Turning this switch on then pressing button X Y or Z causes the machine to return to the zero position for each axis.

9. Lesson 1 The Machine Operation Panel
13. Machine lock 机床锁定
This switch is used to check a new program on the machine All movements of the tool are blocked, while a check is run on the machine screen.
14. Control panel 控制面板
Usually, the control panel is located at the front of the main electronic system and is equipped with a screen and with various buttons and switches.
15. Power on and power off 电源开和关
(1) The NC system is always turned on after the main power switch, located on the door of the electric control system.
(2) The NC system is always turned off before the main power switch is turned off.
16. Reset 复位
This button is used for alarm cancellation or cancellation of an operation, but the “reset” button should not be used while the machine is in the working mode.

10. Lesson 2 Operation Requirement for NC Machine数控机床操作要求
As the NC equipment is automated and very fast so it is a source of hazards. In order to prevent the personnel injures and the equipment damage, operators must be aware of the source of the hazards. Main potential sources of hazard include: rotating parts, such as the spindle, the tool in the spindle, chuck., work-piece in the chuck., and the turret with the tools and rotating clamping devices; movable parts, such as the machining center table, lathe slides, the tailstock center and the tool carousel; errors in the program such as improper use of the GOO code in conjunction with the wrong coordinate value, which can generate an unexpected rapid motion; an error in setting or changing the offset value, which can result in a collision of the tool with the part or the machine.

11. Lesson 2 Operation Requirement for NC Machine
To minimize or avoid hazards, try to remember the following.
1. Keep all of the original covers on the machine as supplied by the machine tool manufacturer.
2. Wear safety glasses, gloves, and proper clothing and shoes.
3. Do not attempt to run the machine before you are familiar with its operation control.
4. Before running the program，make sure that the part is clamped property.
5. When testing a program, follow the following procedure.

12. Lesson 2 Operation Requirement for NC Machine
①. Run the program by using the machine “lock” function; check for errors in syntax and geometry.
②. Slow down rapid motions or run dry program by using the “rapid override” switch;
③. Use a single-block run to confirm each line in the program before running it.
④. When the tool is cutting, slow down the feed rate by using the “feed override” switch to prevent over-cutting.

13. Lesson 2 Operation Requirement for NC Machine
6. Do not handle chips by hand and do not use chip hooks to straighten curled chips. Program different cutting conditions for better chip control. Stop machine if you need to properly clean the chips.
7. If there is any suspicion that the insert will break under the programmed cutting conditions, choose a thinker insert or reduce the feed or the depth of the cut.
8. When supporting a large part by the center, make sure that the hole-center is large enough to support and hold the part.
9. Stop the machine when changing the tools, indexing insert, removing the chips.
10. Replace dull or broken tools or inserts.
11. Write a list of offsets for current tools, and clear the offsets for tools removed from the machine.
12. Do not make changes in the program if your supervisor has prohibited your doing so.

14. Lesson 3 Maintenance of NC Machine 数控机床的维护与保养
Careful maintenance for NC machine can keep good property and prolong the use time. Therefore, operators must execute the maintenance system.
It includes the daily and regular maintenance.
Daily: 每天
1. Make sure that lube in the lubrication tank is enough, pump works properly, way surface is bright and clean.

15. Lesson 3 Maintenance of NC Machine
2. Clean water from the water knockout drum timely to make sure that dryer works normally.
3. Make sure that liquid level in the tank is right.
4. Clean chips from way covers and bottom pan.
5. Clean chips from tool changer.
6. Wipe spindle taper with a clean cloth rag and apply light oil.

16. Lesson 3 Maintenance of NC Machine
Weekly: 每周
Wash dust from each of filter leaves to keep it clean and without block.
Irregular
1. Check cooling liquid tank for proper high level and if cooling liquid is too dirty. Change it.
2. Check chip-removing equipment. It is necessary to clean and change filter.

17. Lesson 3 Maintenance of NC Machine
Monthly: 每月
1. Clean oil level in gearbox. Add oil until oil begins dripping from over flow tube at bottom of sump tank .
2. Clean pads on button of pallets.
3. Clean the positioning pads on the A-axis and the load station. This requires removing the pallet.
4. Inspect way covers for proper operation and lubricate with light oil if necessary.

18. Lesson 3 Maintenance of NC Machine
Six months: 半年
1. Properly adjust spindle driving belt.
2. Clean hydraulic value, oil tank and change hydraulic oil and filter center.
3. Make sure that the fit strip on the way of each axis is fixed firmly..

19. Lesson 3 Maintenance of NC Machine
Annually: 每年
1. If carbon brush of motor is too damaged. Change it timely.
2. Clean and change lube and filter of the spindle box.
3. Clean the used grease on the ballscrew and apply new grease.
Every two years: 每两年
Replace air filter on control box.

20. Lesson 4 Troubleshooting of NC Machine 数控机床故障查找
When troubles appear, examine the correct cause to take proper action. To do this, execute the follow methods:
1. Direct-vision. 直观法
This is a proved method. It means, examining trouble causes by asking, looking, listening, touching and smelling.
1). Asking
2). Looking
3).Listening
4). Touching
5). Smelling

21. Lesson 4 Troubleshooting of NC Machine
2. Alarm function 报警功能法
Each machine has an alarm function. The alarm, function of machine helps decide whether something is wrong with the machine or not.
3. Functional program test 功能程序测试法
Make a function test program with NC system GMST function to determine correctness and precision of the movement.
4. Replacing parts 备件置换法
If there is suspicion that some part has trouble, replace it with a spare part to decide whether the machine has some troubles before the replacement of parts. Make sure that the parameter is consistent when replacing parts.

22. Lesson 4 Troubleshooting of NC Machine
5. Checking parameter 参数检查法
Both the loss of the system parameters and incorrect setting may cause the changes in the functioning of the machine or other troubles. Therefore, once the machine has some troubles, check and correct the system parameter timely.
6. Principle analysis 原理分析法
Use the working principle to analyze the trouble and find out the source of trouble with the machine.