Analysis and elimination of common faults of floor milling and boring machine

1. Common causes and troubleshooting methods related to hydraulic system

1.1 Excessive noise Fault

On the one hand, due to the blockage of the oil filter, the leakage of the suction pipeline, the viscosity of the oil is too high or the oil temperature is too low, resulting in the oil pump suction; On the other hand, because the oil level is too low, the filter is exposed, the suction pipeline leakage, the oil pump shaft seal ring leakage and other reasons, so that the oil foam; Oil pump wear or damage, loose coupling between oil pump and motor, mechanical vibration, etc., can also cause excessive noise.

1.2 Insufficient pressure or unstable failure

Causes of insufficient pressure or instability: air intake of the oil pump or the direction of rotation of the oil pump is not correct; Because the oil pump is damaged or worn, the oil viscosity is too low, resulting in excessive heat of the oil pump; Relief valve or pressure reducing valve failure, performance in the adjustment, no change in pressure or stuck phenomenon; Oil pump suction empty, oil foam, mechanical vibration and so on.

Pressure shortage or unstable removal method to use inspection tubing and oil pump steering; Replace the oil pump, choose the appropriate working oil according to the temperature; Clean the overflow valve and pressure reducing valve, check the wear of the valve, properly repair and check whether the oil path is blocked, and analyze the cause of excessive overflow oil resistance.

1.3 Failure of static guide to float

The reason why static guide can’t float is that the throttle is blocked, the static oil can’t enter the oil chamber, the pressure gauge has no reading or the oil filter is blocked or damaged, and the floating amount is not uniform. Hydrostatic guide can not float to eliminate the method to use the cleaning throttle; Clean or replace the oil filter; Adjust the throttle and other methods.

 

2, common reasons and troubleshooting methods related to the ram

2.1 Ram motor feedback to drive device V57 line fault

The PC input point X401 is not bright. After the power is off again and the power is sent, this point can be restored. The headstock, ram and boring bar share a V57 DC motor drive device, and the headstock works normally. No faults were found in the ram DC motor (7.5KW) and its velocimeter. Sometimes the ram can move a distance at low speed, and the armature voltage of the motor gradually increases beyond DC 460V, or the speed increases a little, and the driving device alarm appears. The feedback circuit of the speed measuring machine has a lOOk ω adjustable potentiometer, and a relay KA14 normally open point is connected in parallel at both ends. The spindle box is closed through KA14 normally open point when working, and the speed measuring mechanical pressure is fed back to the V57 drive device. The ram moves through the lOOk ω adjustable potentiometer to feed the speed measuring mechanical pressure back to the V57 drive.

2.2 Faults of sliding pillow and boring bar ⅱ of boring and milling machine fast immovability or slow starting and moving speed

Check the electrical parameters: armature voltage of dc motor (7.5KW) 378V, current, feedback voltage of velocimeter, V57 voltage value O ~ lOV given by ram and DC excitation voltage of motor 144V are normal. V57 drive device and headstock run well, indicating that motor drive device V57 is without fault. Check the ram and boring bar brake voltage DC 24V, the action is correct. Occasionally when the motor runs, the sound is heavy. Analysis: (1) The DC motor itself has a fault; ② The mechanical load is too heavy. Check the ram, boring bar static pressure, lubrication system oil pressure found no problems. When checking the lubrication of the gear box, lead screw and lead screw, it was found that the lubricating oil pipe position of the lead screw was wrong, and the lubricating oil did not hit the lead screw, resulting in no lubricating oil of the lead screw and lead screw. After a long time, the copper wire was worn, and the operating resistance of the lead screw increased, resulting in the above faults.

 

3. Common reasons and troubleshooting methods related to the main shaft

3.1 The headstock cannot rise quickly, and the headstock jitter and driving motor noise are serious faults when falling rapidly

Check the headstock clamping device, screw and screw hydrostatic lubrication system, electrical drive are normal, but found that the front chain of the headstock is too tight, thus judging that there is a fault in the pillow compensation system.

According to 8 different positions of the ram, 8 stroke detection proximity switches are used to output 0 ~ 10V different DC analog voltage through Mitsubishi PLC FX2N-32MR-001 program controller, so as to change the output pressure of electro-hydraulic proportional valve. The pressure output gradually increases with the forward extension of the ram and gradually decreases with the backward retraction. By controlling the pressure of the oil cylinder in the counterweight balance hammer of the spindle box, the chain tension before and after the spindle box lifting can be changed to compensate the parallel movement of the ram.

3.2 Fault of sudden and fast downward movement of spindle box when it is moving

The reason is that the intermediate relay KA12 pulls in when the spindle box moves down rapidly. This fault appears in Japan Mitsubishi single chip programmable controller PC, because the boring and milling machine has been running for more than ten years, and mitsubishi PC internal related output relay aging, contact adhesion, replacement of a new relay after the fault removal.

3.3 When the spindle starts and the spindle box and column position knob are selected, the spindle automatically stops and fails

After the boring and milling machine starts, 6 oil pump motors work, and each oil pump motor main power line is connected in series with an overheating relay to prevent the oil pump motor from burning. Oil pump motor overheating relay auxiliary contact until mitsubishi PLC X023 input point, because when choosing the spindle box (or column), power distribution cabinet internal relay operation vibration, one of the oil pump motor overheating relay auxiliary contact virtual, instant X023 light flashing, it is hard to find, to the naked eye sticks the impact power distribution cabinet interior panel method, inspection to the point of failure, Replace a new overheat relay after troubleshooting.Guilong manifold blocks