How to prevent settlement and cracking of NGW-L11-5.6 planetary gearbox base

Preventing settlement and cracking of the NGW-L11-5.6 planetary gearbox base requires control throughout the entire process of base design, construction, installation, and maintenance. Specific measures are as follows:
1、 Foundation design and construction phase

Material selection

The concrete base grade should be ≥ C20, the thickness should be ≥ 200mm, and the curing time after pouring should be ≥ 7 days in summer and ≥ 14 days in winter. The surface should be secondary polished (roughness Ra ≤ 6.3 μ m).

It is recommended to use Q235B steel plate (thickness ≥ 16mm) for the steel structure base, and stress relief treatment should be carried out after welding. The top milling accuracy should be ≤ 0.05mm/m.

Settlement prevention

The soil layer below the base needs to be compacted or a crushed stone cushion layer should be laid to avoid uneven settlement caused by soft foundation.

It is recommended to embed settlement observation points for large equipment bases and regularly monitor the settlement amount (allowable value ≤ 0.1mm/m).

2、 Installation and commissioning phase

Flatness control

Use a laser level (accuracy 0.02mm/m) to grid measure the flatness of the base, with an error of ≤ 0.1mm/m. For high-precision scenarios, it is recommended to use an error of ≤ 0.05mm/m.

Compensate for local low points with adjustable shims (0.1mm/0.2mm/0.5mm), with no more than 3 shims per group and a total thickness of ≥ 20mm.

Tightening specifications

Tighten the anchor bolts in three diagonal steps (initial tightening 50% → re tightening 80% → final tightening 100% torque) to avoid deformation of the base caused by unilateral force.

3、 Long term maintenance and monitoring

Regular inspection

Check the torque of the foundation bolts every 3 months to prevent loosening and displacement of the base.

Annually calibrate the coaxiality with a laser alignment instrument (error ≤ 0.03mm/m) to avoid eccentric load accelerating base fatigue.

Exception handling

If settlement or cracking of the foundation is found, re grouting (concrete foundation) or milling repair (steel structure foundation) is required.

When the settlement exceeds the tolerance, it can be fine tuned by injecting epoxy resin grout after lifting with a jack.

4、 Key precautions

Dynamic verification: After running the reducer for 2 hours, retest the flatness and allow the deviation to be relaxed to 1.2 times (≤ 0.12mm/m).

Coaxiality matching: After adjusting the base, it is necessary to check the coaxiality between the input/output shaft of the reducer and the load equipment (error ≤ 0.03mm/m).

The above measures can effectively reduce the risk of foundation settlement and cracking, and extend the service life of the equipment.