1. 445 servo disconnection software alarm: machine tool cannot operate normally

Repair steps:

Firstly, check that the hardware connections of the system are normal, but there is a significant deviation between the feedback values of the servo motor and the grating ruler;  

The second is to modify the function bit parameter of the servo adjustment screen, No.2003.1=0, and cancel the servo disconnection software alarm function. This way, there will be no more software alarm for the 445 servo disconnection, and the machine tool will resume normal operation.

Of course, this method can only be used in situations where precision is not very high, as it eliminates the deviation monitoring function of full closed-loop and semi closed-loop feedback. The complete solution still requires maintenance and adjustment of the mechanical transmission mechanism.

2. There is a radial error of about 8 μ m measured by a three coordinate machine, and there are also quadrant protrusions

The adjustment steps are as follows:

One useful function for eliminating positional deviation is position feedforward. By using this function, delays caused by acceleration/deceleration and servo system delays can be suppressed, and contour errors in machining can be reduced. Adjust the pre reading feedforward coefficient parameter No. 2092 by

Adjust 9000 to 9500;  

The second is to modify the speed loop gain parameter 125 to 180 on the servo adjustment screen, and then fine tune the pre reading feedforward coefficient parameter No. 2092 from 9500 to 9600.

3. The phenomenon of Z-axis oscillation occurs during the operation of the machine tool

The repair steps are as follows:

One is to adjust the position loop gain parameter No.1825 of the machine tool regarding the Z-axis, from 3000 to 2800. When the machine tool is running, Z-axis oscillation has no significant effect. If this parameter is further reduced, the machine tool will trigger a servo alarm;  

Secondly, through observation, it has been found that there is a belt pulley transmission with a transmission ratio of 2:1 between the Z-axis motor and the lead screw. Analysis shows that there may be certain differences between the motor and the Z-axis

Twisting and transmission clearance make it difficult to stabilize the position ring function. By setting the machine parameter 2012.1 (MS FE) to 1, the mechanical speed feedback compensation function is activated, and the mechanical speed feedback gain parameter No.2088 is set to 30. After restarting, operate the machine

The oscillation phenomenon disappears when moving along the Z-axis.

4. The feed axis adopts semi closed loop control, and through machine tool positioning accuracy testing, it was found that each feed axis has a deviation of about 30-40 μ m.

The repair steps are as follows:

One is to adjust and pre tighten the screw nut pairs of each feed axis, and upon further inspection, it was found that there is still a deviation of about 10-20 μ m.

The second is to determine the compensation amount for the feed clearance of each axis, and compensate the measured value in the machine parameter 1851. The compensation amount for the rapid feed clearance of each axis is determined, and the measured value is compensated in the machine parameter 1852.

Thirdly, the feed axes of the machine tool are reset to zero, and the positioning accuracy of the machine tool is checked again. The error is within 5 μ m, which meets the positioning accuracy requirements.

5. After a certain startup, there is an X-axis software overtravel alarm and both forward and reverse directions cannot be started. Pressing the RESET button or restarting cannot eliminate the alarm.

The repair steps are as follows:

One is to set the storage travel limit parameter to invalid, that is, set machine parameter 1320 to 99999999 and machine parameter 1321 to -99999999.

The second is to power on the system again and eliminate the alarm. Perform the reference point operation again, reset the system's stored travel parameters to their original values, and the machine tool will return to normal.

Basic Debugging Parameter Setting Section

1. Setting of decimal point

When using CNC machine tools, some FANUC 0i systems often require a decimal point to be added to the right side of the coordinate word during programming. For example, G00 X100. Y100. F100., which means X100. represents walking 100mm in the X direction. If written as X100, then

It only represents walking 0.1mm in the X direction. The above example is actually set by FANUC 0i system parameter # 3401 (Table 1).

DPI represents addresses that can use decimal points, 0 is considered as the smallest set unit, and 1 is considered as mm

The setting steps for debugging are as follows:

(1) Set NC to MDI mode;

(2) Set FANUC 0i system parameters to "writable" state: (a) Press the function key OFFSET - press the soft key "set"; (b) Move the cursor to the "parameter writing" position; (c) Enter "1" - Press the input key.

(3) Modify parameter value 3401: (a) Press the function key SYSTEM - press the soft key "Parameters"; (b) Enter "3401" - press the soft key "Search"; (c) Move the cursor to 3401 # 0; (d) Enter "1" - Press the input key.

(4) Change the FANUC 0i system parameters to 'non writable' status

The method is the same as the second step, just enter "0".

Through the above modifications, when programming, regardless of whether there is a decimal point on the right side of the coordinate word, the input values are all in millimeters. X100. and X100 both represent the actual 100mm walk in the X direction, which can improve the accuracy and efficiency of program input.

When programming 2G71 and G72, it is often required that the part contour must conform to both the X-axis and Z-axis directions while monotonically increasing or decreasing.

In fact, this feature is determined by parameter 5102 (Table 2), and many machine tools are set to 5102 # 1=1, that is, MRC=1.

When the contour of the part shown in Figure 1 conforms to the shape of increasing or decreasing monotonically in both the X-axis and Z-axis directions, the system will not sound an alarm and the machine tool will process normally.

When processing non monotonically increasing or decreasing shapes in the X-axis and Z-axis directions of the part contour shown in Figure 2 in practical applications, 5102 # 1 needs to be set to 0, that is, MRC=0. At this time, the processing of non monotonic graphic parts will not sound an alarm by the system, and the machine will

The bed is being processed normally.

3. Activation of mirror function

Many machine tool manufacturers equipped with FANUC 0i systems have not enabled the G51 mirror function during parameter debugging. To enable it, the following four parameters need to be set: 5400 # 6=1 (use I, J, K commands for each axis scaling ratio);

5400 # 7=1 (scaling factor unit is 0.001 times); 5401 # 0=1 (effective scaling); 0012 # 0=1 (mirror enabled).