What are the common faults of machining center boring?
- CNC machining center boring accuracy is not up to standard, cylindricity is out of tolerance, the spindle is hot and noisy, but the inspection found that the spindle rotation resistance is smal
fault analysis :
After disassembling the parts of the spindle, it was found that the reasons for the failure were as follows：The preload of the front bearing decreases and the clearance of the bearing increases.The spindle automatic clamping mechanism in part of the disc spring fatigue failure, the tool is not fully tensioned, there is a little movement. The main spindle bearing grease is mixed with dust and water, this is because the compressed air used in the processing center has no fine filter and drying device, so when pneumatic chip blowing a small amount of dust and water into the main shaft bearing grease, resulting in poor lubrication, resulting in fever and noise;There are a few scratches on the positioning surface of the taper hole in the spindle, and the taper hole is not well matched with the taper surface of the shank, and there is a slight eccentricity;
fault handling
Before replacing the bearing and grease, adjust the bearing clearance; Self-made simple grinding tool, manual grinding spindle inner conical hole positioning surface, with coloring method to check, ensure that the contact area between the tool handle and spindle centering conical hole is greater than 85%; Replace the disc spring. Put the repaired spindle back into the headstock and use a dial meter to check whether the radial runout meets the standard. Test machining, spindle temperature rise and noise normal, processing accuracy to meet the requirements of processing technology troubleshooting.
improvement measure
Add compressed air fine filter and drying device, filter to drain regularly, regularly clean or replace the filter element; Check the cleaning and matching condition of spindle taper hole and tool handle at any time, check whether the air dryer works normally;Reasonably arrange the processing technology to avoid the sudden change of material removal rate; Overload operation is strictly prohibited. In case of failure, it shall be reported for repair in time. It is not allowed to operate with disease.
- The pull rod steel ball of the spindle component is damaged
fault phenomenon： Machining center tool change impact noise, the spindle front end toggle handle rotation of the location key local deformation.
fault analysis :Inspection found that the spindle loose knife action and manipulator pulling knife action is not coordinated. This is because the limit switch iron is installed in the tail of the cylinder of the gas-liquid pressurized cylinder, although the cylinder piston action is in place, the piston action of the pressurized cylinder is not in place, resulting in the manipulator in the handle has not been completely loosened under the circumstances of forced drawing, damage rod ball and tension screw.
fault handling：Clean the pressurized cylinder, replace the sealing ring, fill the pressurized cylinder with oil, and adjust the air pressure to 0.5~ 0.8mpa until the fault is removed.
improvement measure：Regularly check and clean the gas-liquid booster cylinder, monitor the running status of each part of the tool automatic clamping mechanism, and eliminate the hidden trouble in time; Check and adjust air pressure and hydraulic system pressure regularly, check hydraulic oil quality, such as oxidation deterioration should be replaced in time.
- The locating key of the spindle component is damaged
fault phenomenon：CNC machining center tool change impact noise, the spindle front end toggle handle rotation of the location key local deformation.
fault analysis :The noise mainly appeared in the manipulator tool insertion stage, and the fault was initially determined as the spindle quasi-stop position error and tool change reference point drift. The incorrect position of the spindle may be caused by the variation of the electrical system parameters of the spindle stopping device, unreliable positioning or the radial runout of the spindle. First check the installation position of hall components, it was found that the fixing screw was loose, and the keyway of the handle was not aligned with the front positioning key of the spindle when the manipulator inserted the knife, and the positioning key was damaged.
The installation position of the spindle tool change reference point close to the switch is also loose, so that the tool change reference point moves down slightly. When the tool handle is inserted into the spindle cone hole, the cone directly hits the spindle centering cone hole, producing abnormal sound.
fault handling：After adjusting the installation position of hall components, tighten and apply anti-loose glue. Adjust the installation position of the proximity switch of the spindle tool changing reference point, replace the positioning key at the front of the spindle, and the fault disappears.
improvement measure：Check and clean the spindle quasi-stop device and spindle tool change reference point positioning device regularly, pay attention to observe the state of the tool handle inserted into the spindle cone hole, and eliminate the hidden trouble in time.
What are the causes and solutions for abnormal operation of three axes in machining center?
failure cause:
- Bearing failure
- The lead screw busbar and guide rail are unbalanced
- The wear-resistant plate is seriously worn, resulting in serious scratches on the guide rail
- Servo motor gain mismatch
fault handling:
- Replace the bearing
- Correction screw rod bus
- Re stick the wear-resistant plate. If the guide rail is scratched too seriously, it shall be handled again
- Adjust servo gain parameters to match the machine
