Causes of vibration in cylindrical grinders:
1. Excessive vibration during high-speed rotation of the grinding wheel; if the wheel has not undergone dynamic balancing, significant vibration occurs, compromising machining accuracy.
2. The motor chuck requires dynamic balancing; even if the grinding wheel itself is balanced, a lack of balance at the motor end will still adversely affect grinding accuracy.
Solutions:
1. If vibration is severe, perform in-situ dynamic balancing. Use a dynamic balancing instrument to determine the precise positioning angles for the three sliding weights on the grinding wheel flange; typically, 3–4 adjustments are sufficient to rapidly reduce vibration. After balancing, vibration levels should be controlled within the 1.5 µm to 0.05 µm range; the wheel is then dressed, after which machining can proceed immediately.
2. Measure motor vibration; if it exceeds 2 µm, perform dynamic balancing on the motor as well to prevent it from compromising accuracy at the grinding wheel.
Common faults for cylindrical grinders:
(1) Poor contact at the mounting interface of the diamond tool holder;
(2) Excessive clearance (out of tolerance) in the grinding wheel head spindle;
(3) Improper parameter selection for workhead rotation speed or wheel dressing speed during grinding;
(4) Mismatch between the selected grinding wheel model and the workpiece material.
Solution:
(1) Re-scrape and fit the diamond tool holder to ensure a secure, high-quality mating surface. After fastening, use a dial indicator to check the diamond tool tip; deflection during manipulation should not exceed 0.01 mm. Additionally, factors such as the sharpness of the diamond tool must be considered.
(2) Ensure the clearance (both radial and axial) of the hybrid (hydrodynamic/hydrostatic) grinding wheel spindle falls within specified limits (radial: 0.027–0.03 mm; axial: within 0.02 mm). Also, verify that the hydrostatic pressure is maintained within the standard range (15–18 kg/cm²), confirm that hydrodynamic pressure has been properly established, and check the oil flow from each nozzle.
