The solution to the alarm of CNC horizontal boring and milling machine

TK6411A CNC horizontal boring and milling machine, the CNC system is SIEMENSSINUMERIK 802D. When turning on the reference point once, the CNC machine tool alarm: 20002 channel 1 axis X1 zero reference point mark is not established.

Check the 802D diagnosis manual to know: the zero pulse of the x-axis incremental position encoder is not within the specified displacement. Before then, the machine tool works normally. In line with the principle of easiness and difficulty: swap the power modules of the X and Z axes, or display the above alarm, indicating that the module has no problem (because the z axis returns to zero). Check the zero return deceleration stop of the shaft, no looseness is found, you can

Troubleshoot the stop. Change the zero pulse distance set in the axis parameter MD34060REFP MAX-MAR-KER_DIST of the axis from the original 10ram to 50ram. Turn on the machine again to zero, and the fault remains. Shut down, pull out the encoder plug of the axis servo motor, open the encoder cover, and find that there is water mark at the encoder socket, and there is also water inside (because the mold processing is cast aluminum, tool cooling water).

It is estimated that the guard plate is not tightly sealed, and there is long-term water infiltration. First dry it with a cloth, and then use a hair dryer to dry the plug and socket and the encoder, re-plug the plug, the system is powered back to zero, the fault disappears, and the machine tool works normally. Later, add a small guard plate to the motor to ensure that the cooling will not enter.