How To Adjust The Clearance Of A Copper Wire Granulator Bearing After Installation?

I. Clarify the adjustment target: Axial clearance vs. radial clearance

Axial clearance: refers to the relative movement between the inner and outer rings of the bearing in the axial direction, mainly affecting the positioning accuracy of the shaft and thermal expansion compensation.

Radial clearance: refers to the clearance between the rolling elements and the raceways of the inner and outer rings, directly affecting the bearing's load-bearing capacity and friction state.

Most copper wire granulator spindle bearings (such as tapered roller bearings and self-aligning roller bearings) require focused adjustment of axial clearance to adapt to high loads and temperature changes.

II. Common adjustment methods and operating steps

1. Shim method (applicable to end-cap fixed structures) Axial clearance is controlled by increasing or decreasing the thickness of the shims between the bearing end cap and the bearing housing.

Operating Procedure:

Install the bearing without shims, tighten the end cap screws, and simultaneously rotate the shaft by hand to ensure full contact between the rolling elements and the outer ring;
Measure the clearance between the end cap and the housing at this point;
Calculate the required total shim thickness based on the equipment's required axial clearance (typically 0.05–0.15mm) = measured clearance + working clearance;
After installing shims of the appropriate thickness, retighten the screws.

✅ Advantages: Intuitive operation, suitable for scenarios with moderate precision requirements;

❗Note: Shims should be made of pressure-resistant, non-deformable materials (such as soft steel sheets or elastic paper) to avoid compression deformation affecting accuracy.

2. Bolt Method (Applicable to Adjustable Pressure Cap Structures)
Apply pressure to the bearing's outer ring using adjusting bolts, controlling the clearance by rotating the bolts.

Operating Procedure:

First, measure the pitch of the adjusting bolt (e.g., 1.5mm);
Slowly tighten the bolt until there is no axial play, and record the position;
Rotate the bolt in the opposite direction by the corresponding angle according to the required clearance (e.g., 0.5mm) (e.g., reverse 360° for a 1.5mm pitch);
Use a locking shim to lock the bolt position and prevent loosening.

✅ Advantages: High adjustment accuracy, suitable for high-precision or heavy-load conditions;

❗Note: A locking device must be used to prevent loosening during operation.

3. Push-Pull Method (Applicable to Tapered Roller Bearings)
The clearance is determined by measuring the shaft displacement through axial pushing and pulling.

Operating Procedure:

Push the shaft to one extreme position and measure the shaft end displacement with a dial indicator;
Then pull it to the other end and record the difference between the two readings;
Adjust the shims or nuts to make the difference conform to the specified range (generally 0.05–0.1mm).

✅ Advantages: Directly reflects the clearance under actual working conditions;

❗Note: Interference from loose components should be eliminated during measurement.

III. Verification and Operation Monitoring After Adjustment

Manual Rotation Check: The shaft should rotate smoothly without jamming or significant axial movement.

No-Load Test Run: Run for 10–30 minutes and monitor:

Whether the bearing temperature stabilizes after a steady rise;

Whether there is any abnormal vibration or noise;

Whether the motor current is normal.

Status Data Recording: Record the initial vibration value, temperature, and clearance setting value as a benchmark for subsequent maintenance.

IV. Special Recommendations for High Dust and High Temperature Conditions

Given that copper granulators often operate in high dust and high temperature environments:

When adjusting the clearance, allowance should be made for thermal expansion to avoid "seizing" due to clearance loss caused by temperature rise during operation;

Preferably use sealed bearings or install dust covers to reduce the risk of contamination;

Use condition monitoring methods (such as ultrasonic sensors and thermometers) to dynamically verify the adjustment effect and improve reliability.