What are the common faults of vertical lathes?

I. Spindle System Faults

1. Spindle overheating and decreased rotational accuracy

Causes: Dust or moisture mixed into the spindle bearing grease, damage to the centering taper hole, insufficient bearing preload, fatigue failure of the clamping spring.

Symptoms: Machining hole diameter is too large, poor cylindricity, excessive noise.

Solutions: Replace bearings, grind the taper hole, adjust preload, add an air drying filter.

2. Excessive spindle bearing clearance

This leads to excessive cylindricity or excessive taper in the finish turning of the outer diameter, requiring readjustment of the bearing clearance.

II. Tool Post and Feed System Faults

1. Tool post crawling

Causes: Overly tight wedge plate, bent wedge, poor guide rail lubrication, or blocked oil passages.

Solutions: Loosen the wedge plate appropriately, straighten the wedge, clean the oil passages, and replenish lubricating oil.

2. Turret not rotating and relay no signal

Cause: Control circuit fault or system malfunction. Check the connection between the computer and control box.

3. Automatic tool change malfunction

Cause: Mechanical structure jamming or sensor failure. Check and calibrate the system.

III. Hydraulic System Faults

1. Severe oil leakage from the vertical tool post

Cause: Loose sealing ring, loose vent screw, damaged seal, or blocked return oil.

Solution: Tighten the seal, repair damage, and clean the oil circuit.

2. Oil pump automatically stops after starting

Cause: Thermal relay setting too low or oil pump malfunction. Adjust the relay or repair the oil pump.

3. Spindle box shifting or unstable table operation

Cause: Caused by pressure holding failure, internal leakage, or improper auxiliary unloading design during modification or use. Optimize the hydraulic circuit and install an accumulator.

IV. Electrical and CNC System Alarms

1. Servo System Alarms (e.g., overload, encoder signal loss)

Mostly caused by loose cables due to vibration, motor overheating, or large load fluctuations. Connections and heat dissipation need to be checked.

2. System Parameter Disorders or Program Errors

Manifested as "coordinate overtravel" or "syntax error." The program needs to be verified through simulation; back up parameters before modification.

3. Abnormal Beam Lifting

Electrical control failure: Limit switches not triggered, thermal relays tripping. Reset or repair is required.

V. Machining Quality Faults

1. Rough Machining Surface

Causes: Excessive feed rate, excessive depth of cut, insufficient cutting fluid, or tool wear.

Solutions: Reduce feed rate, decrease depth of cut, increase cutting fluid supply.

2. Machining Dimensional Deviations

Causes: Guide rail wear, tool wear, or improper machine tool adjustment. Regular inspection and replacement of worn parts are required.

3. Tool Drop During Turning

Causes: Large fluctuations in the tool holder's balancing oil pressure or brake failure. Check the overflow valve, oil suction pipe, and electrical system.

VI. Other Common Abnormalities

1. Excessive Operating Noise: Damaged bearings, loose transmission, or insufficient lubrication. Tighten components and add lubricant.

2. Unresponsive Table Speed ​​Change: Abnormal operation of the solenoid valve or stuck push rod. Check the circuit and limit switches.

3. Loud Noise During Crossbeam Lifting: Poor lubrication of the leadscrew, excessively tight pressure plate, or bent leadscrew. Add oil, adjust, or straighten.

It is recommended to establish a regular inspection system, focusing on high-frequency wear components (such as bearings, seals, and hydraulic valves). Preventative maintenance can significantly reduce the failure rate.