How to Fix a Grinder Machine?

How to Fix a Grinder Machine?

Overview of Grinder Maintenance

Grinder machines are precision machining equipment with diverse types, including surface grinders, cylindrical grinders, centerless grinders, and internal grinders. Although their structures vary significantly, they generally consist of mechanical systems, hydraulic systems, electrical control systems, and lubrication systems.

During maintenance, adhere to two fundamental principles:

Safety First: Always disconnect power and relieve pressure before servicing. Wear safety goggles and insulated gloves to avoid working with live electrical components or under pressure.

Systematic Diagnosis: Observe symptoms first, then conduct step-by-step inspections. Avoid “blind disassembly,” as this may exacerbate damage.

Fault Diagnosis and Inspection Process of Grinder

Common Fault Symptoms

Decreased machining accuracy (unstable workpiece dimensions, worsened surface roughness).

Abnormal noises, stuttering, increased vibration.

Hydraulic system pressure insufficiency or excessive temperature.

Electrical alarms, such as FANUC system 319 encoder alarm, servo overload.

Inspection and Diagnosis Procedure

On-site inspection: Observe grinder machine operation, listen for abnormal noises, check for fluid leaks, and feel for excessive heat.

Lubrication system inspection: Check oil pump pressure (typically 0.3–0.6 MPa) and fluid cleanliness. Blackened or emulsified oil indicates replacement is needed.

Mechanical component inspection:

Measure spindle radial runout with a dial indicator; it should be controlled within 2 μm.

Guideway wear can be detected using a laser interferometer or leveling instrument.

Lead screw clearance is determined through bidirectional movement testing.

Electrical System Inspection:

• Check servo drive alarm codes.
• Use a multimeter or oscilloscope to verify power supply and motor output stability.
• Reset origin parameters for absolute encoders if necessary.
• Common Inspection Tools
• Dial indicator, dial gauge
• Vibration analyzer
• Hydraulic pressure gauge
• Laser alignment tool

Core Component Maintenance Techniques of Grinder

Spindle System

Rolling Bearing Replacement: Require heat-mounted installation to prevent impact damage; use a puller for disassembly. Maintain bearing cleanliness during installation to prevent contamination.

Hydrostatic Bearings: Clean oil passages, replace filter elements, inspect oil film thickness, and adjust clearances.

Spindle Regrinding: Regrind by less than 0.1mm to prevent surface hardening layer damage.

Guideways and Transmission Mechanism

Guideway Repair: Restore parallelism via manual scraping or plastic coating. Scraping must maintain contact points at 25 points/25×25mm².

Lead Screw and Worm Gear Pair: Adjust nut clearance to ensure feed sensitivity and transmission smoothness.

Hydraulic and Lubrication System

Regularly clean sediment from the bottom of the oil tank.

Maintain hydraulic oil operating temperature between 40–55°C. Install additional cooling equipment if temperature exceeds 60°C.

Verify responsive operation of relief valves and directional control valves.

Electrical and Control System

Encoder failure: Reinsert cables, clean dust, replace if necessary.

Servo alarm: Troubleshoot step-by-step per manufacturer’s manual; common causes include motor overload or inadequate driver cooling.

Parameter restoration: For FANUC systems, back up system parameters before maintenance to facilitate recovery after failure.

Maintenance Key Points for Special Grinder Machines

Hydrostatic Bearing Grinding Machines: Focus on oil circuit stability. The oil pump must maintain continuous oil supply, and copper filter plates require regular replacement.

CNC Grinding Machines: In addition to mechanical maintenance, back up and restore PLC programs and servo parameters to prevent downtime caused by program loss.

Preventive Maintenance and Care

Daily Maintenance

Clean the grinding wheel and work surface daily.

Check grinding wheel balance to prevent vibration affecting accuracy.

Degauss the magnetic work table after each use to avoid residual magnetism affecting magnetic force.

Periodic Maintenance

Monthly: Inspect the hydraulic oil reservoir, clean the filter element, and replace the coolant.

Semi-annually: Readjust the spindle bearing preload; inspect and calibrate the guideway accuracy.

Annually: Test the motor insulation resistance to prevent insulation aging.

Conclusion

Grinder maintenance is a comprehensive task integrating mechanical, electrical, hydraulic, and CNC expertise. Only through scientific diagnostic procedures, precise repair operations, and standardized preventive maintenance can grinders sustain long-term high precision and stability. Through systematic training and accumulated experience, maintenance personnel can not only enhance efficiency but also significantly reduce equipment downtime risks.

Tags: Grinding Machine, Surface Grinder