On the Economical CNC Lathe typical fault diagnosis and maintenance

Abstract: The development of electronic technology and the development of CNC equipment makes the NC device prices lower, especially in the Economic-based NC system is the price reached its lowest point. Economical CNC Lathe machining Industry in China has been rapidly growing popularity, making the level of processing machinery in China in terms of processing quality or in the processing efficiency has also been a rapid increase, but with the extension of time as the machine, CNC machine tools will be this or that kind of failure, this type of CNC machine tools on the economy common faults, for example, talked about some solutions.

Keywords: CNC lathe Hall switch relay servo

First, the tool change device failure

NC tool general process is: ATC ATC signal by connecting the motor through the worm gear driven rotary knife, knife issued by the Hall element position signal, the CNC system and then use this signal is compared with the target to determine tool is in place. knife change in place, tighten the motor reverse knife in my repair process of NC met the following symptoms.

Fault 1: a four-cutter CNC lathe, cutter One can not find the place, the other potential energy of the normal knife tool failure phenomenon.

Failure Analysis: As the only One can not find the cutter knife, you can rule out mechanical transmission problems, electrical failure is identified. May be the cutter of the Hall element and the problems around the circuit, causing the tool bit signal can not transfer to the PLC. control circuit using a multimeter to check and found: 1 cutter Hall element of the normal power supply 24V, GND line as normal, T1 signal is normal. it can be concluded that damage to the Hall element signal can cause the cutter issued.

The solution: replacement of the Hall element after troubleshooting, found at the normal knife.

Fault 2: a six-cutter CNC lathe, cutter tool, all can not find, after a few weeks to stop rotating turret, and numerical control system alarm display tool: tool change time-out or no signal input.

Failure analysis to find: for the failure, you can still rule out mechanical failure, electrical failure due to blame. Produce the failure of the electrical following reasons: 1. Magnetics off; 2 six Hall element while all the damage; 3 . Hall element of the power supply and signal circuit open circuit results in no output voltage signal which causes the third most likely, so got the schematic, use a multimeter to the Hall element of the electrical circuit to check the power supply line results found : tool carrier detect line to the terminal strip 24V supply voltage of 0V, the other lines were normal. to look along the lines for clues, find the 24V leads from the electrical cabinet thread off, connected still no response. Judging should be is the line break caused by failure.

The solution: replace the use of the same size wire after disconnecting, troubleshooting.

Failure three: a system with FANUC-0imate Dalian Machine Tool Factory six cutter lathe, tool selection cutter normal but when selected does not lock in place after the system alarm: tool change out.

Failure analysis to find: Knife tool selection normal, normal being transferred is not the reverse lock. Shows the normal worm drive, an initial electrical wiring problem in the machine turret control electrical schematics, found the reverse locking tool position signal by a position switch to control the issue, is not the switch that routes around the problem then? In order to confirm the cause of the malfunction, open turret of the top and side covers, reference circuit using a multimeter check the lines and found no line open circuit and short circuit, reverse lock knife by hand pressing the switch position to observe the ladder shows a signal input, thus excluding electrical wiring problems. inference may block movement is not in place, position, micro switch is not operating. then re- tool change time to look, and found that: not really block movement in place. then tighten the bolts to block, a normal test tool. pulls a knife, the original fault has emerged, also found that the worm side of the shaft slipping and climbing phenomenon. Is it caused by the motor when the reverse lock position switch block can not be put in place? so the sleeve for the axial positioning of the handle, the knife cover installed results turret lock normal.

Solution: axial positioning of the sleeve for troubleshooting.


Second, the power supply failure

Machine when the machine running the lights suddenly does not shine, the machine operator panel lights do not light, the system power supply is normal, while the emergency stop alarm system, and the spindle no signal warning. Again after power failure shut down still.

Links to free download http://www.hi138.com failure analysis of inspection: The operator was asked, no irregularities, remove man-made reasons, you can rule out mechanical causes, is caused by electrical fault which the electrical machine diagram shows that these regions and loss of power on 24V, and the machine has two power supply, one I / O interface power supply, one for system power. energized area with I / O interface for, then open observed electrical cabinet I / O interface power supply failure indicator light, indicating that the power supply not working or damaged by the power supply works know that power supply has short circuit and overload protection function, when short circuit or overload the power off automatically when the power output, in order to protect the power circuit from being damaged. so try to remove the power supply output to the load line, and found that re-power after a power indicator light which indicates power supply itself is not damaged by analysis showed that the power supply for the I / O interface power supply, the load is not, nor will not overload, the output circuit is short-circuit fault along the output line number to check that there is a 24V + output line connector from the insulating tape exposed and exposed to the machine bed. The reason is obvious: As the line and machine-to-ground short circuit occurred, causing the power supply in a state of self-protection, making the operation panel, and some I / O interface relay power to stop, causing a more failure. As for the 24V inverter alarm signal may not place an alarm.

The solution: use insulation tape to joints to re-wrap, re-power is turned on all the troubleshooting, remove the alarm lights are bright.

Third, the system program lock failure

A CNC lathe, with FANUC-0i-mate system can not enter values ​​for parameters such as knives, can not edit the program, accompanied by the police.

Failure analysis of inspection: this phenomenon was first thought of the program protect switch, found by comparing the normal system: when the system locks the same phenomenon, so suspect that the system lock switch is broken, but after a short, still can not solve the problem by observing failure The ladder system that X56 no input signal input, indicating that this input circuit breaker. along this line number to use a multimeter to check and found the back selected in the control panel switch connector at the thread off-axis, leading to the line input signal not to PLC logic is not correct, only the failure to occur.

The solution: use the soldering iron to solder off the thread re-soldered, alarm reset, the parameter input is normal, the fault disappears.


IV Conclusion

Maintenance over the case, as similar to the troubleshooting information. In general, for any failure, the first is based on the phenomenon, according to the principles to determine the point of failure, analysis of every possibility, such as a switch, a cable connector, a screw will be will be is the cause of the malfunction, the light before the operation, maintenance history analysis can help narrow the search range, help to improve the efficiency of maintenance.


References:
[1] FANUC-0i-mate manual.

[2] Dalian Machine Tool Group CNC lathe electrical manual.

[3] GSK GSK980T manual.

[4] Shenyang Machine Tool Group CNC lathe electrical manual.

[5] Wang Kanfu. NC machine tool failure diagnosis and maintenance. Machinery Industry Press.


Links to free download http://www.hi138.com