In the operation and management of CNC lathes, in order to ensure the efficiency of CNC lathes, the first step is to reduce the frequency of faults. With the continuous improvement of technology, the frequency of faults in CNC lathes has gradually decreased in recent years. However, there are three major faults that still accompany the operation of CNC lathes, which are mainly related to operation and Today, Shandong CNC lathe will explain the three major faults that affect the normal operation of the lathe regarding maintenance issues.
1、 The motor drive device 6RA27 of the CNC lathe workbench occasionally triggers an "F14" alarm
F14 alarm: The actual excitation current is less than 50% of the given current.
Due to the irregular occurrence of the "F14" alarm, the vertical lathe workbench malfunctions and cannot operate normally.
(1) Check the excitation resistance, voltage, current, and control circuit plug-in, cable (or control wire) connector of the 125kW DC motor on the workbench. After multiple inspections, no fault points were found, so it is suspected that there is an internal fault in the driving device.
(2) Check the internal control components and parameter configuration of the workbench motor drive device 6RA27. Check the electronic components of the internal circuit board of the device for virtual connections, and no fault points were found. Therefore, adjust the internal parameters related to excitation when adjusting P76 (the ratio of the rated excitation current of the motor to the rated excitation current of the device)Score), the original value was 66. When adjusting the P76 parameters, it gradually increases from 1. When the P76 value continuously increases to above 43, the excitation output voltage and output current values are discontinuous, with intermittent jumps in the middle. Observe the current value of the excitation output ammeter as follows: 5A → 8A → 10A; Measure the excitation output voltage with a multimeter:113V→130V→172V。 Therefore, it indicates that the fault point is inside the motor drive device, which is caused by the failure of electronic components inside the A1203 board. The thick film circuit board inside the board was replaced and the fault was resolved.
(3) After replacing the circuit board, a system optimization process must be carried out on the device to ensure stable operation of the motor drive device 6RA27.
2、 Fault of hydraulic pump for spindle bearing of CNC lathe workbench The vertical lathe operates 24 hours a day, and the hydraulic pump for the workbench bearing keeps working. Over time, the hydraulic pump will inevitably cause certain wear and tear. The pump station includes a 0.75kW AC motor, 1 CB-B4 hydraulic pump, 1 Y-25 overflow valve, 1 one-way valve, and 2 filters, with an output oil pressure of 1MPa. But there was a malfunction It is necessary to analyze the cause of the malfunction, otherwise it will lead to many detours.
(1) Hydraulic pump vibration. The analysis of hydraulic pump vibration includes the following points: ① Due to the hard connection between the hydraulic pump and the motor, the coupling is worn or the machining accuracy of the new coupling is insufficient, which exceeds the allowable range. ② The clearance between the outer ring of the fixed hydraulic pump motor end cover bearing is large, which may occur due to wear or installation. ③ Electric motor and hydraulic pump During installation, the positioning accuracy of the connection decreases and is not concentric. ④ The diameter of the inner hole of the coupling has increased due to wear. ⑤ The bearing of the hydraulic pump motor is damaged. ⑥ The hydraulic pump is damaged.Once, the insufficient machining accuracy of the coupling caused the hydraulic pump to vibrate; Once, there was a large clearance between the outer ring of the fixed hydraulic pump motor end cover bearing, which caused the hydraulic pump to vibrate due to wear or installation gaps.
(2) The hydraulic pump has no lubricating oil output. There are several points in the analysis of the hydraulic pump without lubricating oil output: ① Two connection keys in the coupling are damaged, and the hydraulic pump motor is disconnected from the hydraulic pump. ② The overflow valve is not adjustable and the valve components are stuck. ③ The hydraulic pump has air flow output, and the oil suction pipe and connecting copper pipe joints are cracked. ④ Oil suction filter screen clogged。⑤ The hydraulic pump is damaged.The connection between the copper suction pipe and the pump was cracked and leaked, resulting in no lubricating oil output from the hydraulic pump.
3、 High static oil temperature on CNC lathe workbench The fault phenomenon is that it was summer at that time, and the oil temperature gauge on the workbench showed high oil temperature, which had reached the limit value, and the vertical lathe could not operate normally.
(1) Check the floating thickness of the oil film on the workbench. The quality of the workpiece processed on the workbench is 110t, and the self weight of the workbench is 125t. Turn on two large and one small hydraulic pumps. The oil film floating thickness of the workbench is 0.20~0.22mm, and the floating standard of the workbench is ≥ 0.12mm. This indicates that the oil supply pump station of the workbench is working normally.
(2) Check the temperature of the oil tank in the pump station of the supply workbench, and use an infrared thermometer to detect that the temperature of the oil tank is 28 ℃, and the oil temperature is within the normal range.
(3) After checking the temperature gauge, worktable temperature measurement components, and control circuit components, it was found that there was a virtual connection between the left and right guide rail temperature measurement conversion switches and their contacts. After using fine sandpaper for treatment, the worktable oil temperature fault was resolved.
The above are the three major faults that affect the normal operation of Shandong CNC lathes analyzed. We hope that the above description can be helpful for everyone in operating CNC lathes in the future.