First confirm the tool post fault, generally divided into two 1 electrical fault: transmitting coil, the control switch, the line...Part of the fault 2 mechanical failure;Such as scrap iron foreign body into the head card dead body, the mechanical structure rust stuck, bearing jammed, dowel aging jammed, head shaft bending...A square head, economical nc lathe structure and principle of action
Economical nc lathe square head completely controlled by electrical, while its function the same as the ordinary lathe square head, but the structure already had a big change, its structure is as follows:
1 - cover;2 - transmitting plate;3 - small nut;4 - magnetic steel;5 - big nut;6 - clutch disc;7 - screw;8 - end tooth;9 - the blade;10 - worm gear;11 - axis;12 - the cushion for leaning on,13, 27 - against by pin;14 - the blade;15 - hall element;16 - magnetic steel;23 - coupling;24 - check back loops;25 and clutch pin;26 - pin plate;27 - pin
1. The effect of main components: prime mover: motor;Mechanical transmission parts: worm, 10, 11, 7, 26;Basis: 9, 14;Position sensing element: 2, 15, 16;Mechanical positioning: 25, 27, 12, 13. 
2. The structure shows that: (1) the original copy of stillness: motor, 9, 11, 24, 5, 2, 3, 15.(2) transmission: the motor shaft.23 - worm - 10 and 7 (female, axial 11 for external thread).(3) mechanical rough positioning: blade 14 underside face positioning and the blade 9 end tooth meshing.(4) mechanical precision positioning: clutch pins and put the blade on the 14 and 7 clutch screw complete precision positioning.(5) system positioning: 15 HuoEr element contains four location corresponding to the four knives, fixed instruction of each tool, tool on the magnetic steel after completion system instructions. 
3. The principle of action: (1) loosen: system issue instructions - motor startup - worm rotation - 10 worm gear screw rotational 7-11 blade along the central axis of 14 vertical rise on (14 bottom end face of the blade on the positioning and the blade 9 end tooth in meshing state, blade 14 can't turn on) - > face positioning teeth out completely.(2) change knife: 14 rotating blade (clutch pin with screw blade on 25 to 14 7 together) - turning tool.15 (3) location: HuoEr element (there are four position corresponding to the four tool) and instruction corresponding knife 16 - a signal on the magnetic steel, tool post motor into reverse.(4) lock: clutch pin 25 separate the blade on the 14 and screw 7 - clutch disc drive screw 6-7 lock down on 14 - > change the knife blade to complete (the reverse time of the motor is the system parameter setting, there will not be too long too short, too short rest can't lock, easy to burn out too long telegram motivation......). 
Second, the disassembling process of tool post
1. Remove the cover 1, recognize letters offer 2 different colors on the wire position, then remove the small nut 3, transmitting plate 2 and 4 magnets. 
2. The screw out big nut 5 within two M4 screw, remove the nut 5 and check out 24, plane bearing and clutch plate (6). 
3. Turn up the blade 14, remove the outer end tooth 7 8, screw, nut, 18, clutch pin 25 pin 13. 
4. Remove the motor wire, down under the motor and blade connecting bolts, down the motor. 
5. 11 on the lower cover screw down axis, take out the lower cover, 10, axial worm gear. 
6. Remove the worm and bearing. 
7. All parts before assembly cleaning oil, grease on the transmission parts. 
8. According to remove the assembly sequence. 
Three, four common fault analysis tool rest
1. Electric tool post every tool rotation.The cause of the problem: transmitting dish without or COM + 24 v input;Knife bit + 24 v low voltage, pull up resistance of lines open;Good tool level signal parameter is not set;Hall element damage;Magnetic block fault, non-magnetic or weak magnetic magnetic block. 
2. Electric tool post did not turn.The cause of the problem: rest motor opposite phase or three phase;System of the forward control signal without output;The forward control signal output system is normal, but the primary circuit control signal circuit or component damage;Tool carriage motor without power supply;Mechanical stuck;Tool carriage motor damage. 
3. The rest is not tight lock.The cause of the problem: not for transmitting plate position;Locks the system time is not long enough;Mechanical locking mechanism of failure. 
4. Rest one knife, turn on, the rest of the tool can turn.The cause of the problem: the hall element damage a knife;The knife line open circuit, system can't detect in position signal;The tool of signal receiving circuit has a problem. 
5. Rest sometimes turn to be not moved.The cause of the problem: the head of control signal interference;Tool post internal mechanical failure, caused by occasionally stuck;The tool of signal receiving circuit has a problem. 
6. Input the number dao can turn the tool post, press tool change tool rest can't directly.The cause of the problem: the hall element from magnetic blocks, placed in a magnetic block, in front of the manual key in knife, tool post just a rotating tool rest in position signal is detected, the then immediately turn head;The manual tool change key failure.