Application of a Locking Assembly in a Ball Mill for Cement Production

In cement production, especially in large-scale cement plants, the reliability of mechanical components is crucial from raw material extraction to grinding, mixing, homogenizing, and storage. One of the most critical factors influencing system stability is the quality of the shaft to gear connection, where high torque transmission occurs under continuous load.

In this case study, Dai Hong Phat introduces a real-world solution using Locking Assemblies from RINGFEDER Germany. These high-precision components resolved recurring failures in a ball mill used for raw material grinding

1. Problems occurring in the cement plant for ball mills

Ball mills are important equipment in the raw material grinding process in cement production. After a thorough inspection of the ball mill assembly by the maintenance engineers, the source of the problem appeared to be the shaft-to-gear joint, or more precisely the locking assembly that connects the shaft to the gear. Measurements showed that this assembly was outside the tolerance of 300 to 400 µm.

To determine the reason for this unusually high run-out value, the decision was made to remove the locking device and reinstall and re-tighten it. However, removal proved to be impossible and neither the ball mill manufacturer nor the local locking assembly supplier could assist the maintenance engineers in this task.

2. The Harm of Using Counterfeit Products

Since the supplier of the installed locking device was unable to provide a solution and since the plant downtime was causing significant losses to the mill operator, RINGFEDER was contacted for help and support. A Ringfeder engineer immediately went to the factory to find out the reason for the problem.

After a detailed inspection, the technical team discovered that the Power Lock device installed on the machine was a fake copy of the Ringfeder RfN 7015.0 size 340x425 product line. This copy was broken into many pieces, which was one of the causes of all the problems. This destruction not only caused strong vibration and damage to the related parts, but also created a risk of labor safety and prolonged production stoppage. In particular, the repair cost and production interruption can reach hundreds of thousands of USD if not handled promptly.

3. RINGFEDER's Solution: Precision from the Shaft Lock

The professional engineers from Ringfeder conducted a surface inspection of the shaft and gear, then they came up with a solution to use the RfN 7015.0 locking devices with suitable parameters. Thanks to the extremely high mechanical precision (machined to strict tolerances), the genuine product allows for precise alignment between the shaft and the gear, minimizing eccentricity.

The result: after installing the new Ringfeder shaft lock, the eccentricity was reduced to only 80 µm, which is within the safe range for continuous operation. At the same time, the vibration of the ball mill was also significantly reduced. The system returned to stable operation without any other structural changes.

4. Why Choose Genuine Ringfeder Shaft Lock?

The above practical case shows that, in heavy industrial applications - where high torque transmission is required - the choice of genuine, high-quality and suitable transmission equipment is a necessary condition for stable and durable machine operation:

- Simple and quick assembly and disassembly, completely maintenance and wear-free, completely gap-free power transmission, manufactured to the highest quality standards. 

- They are suitable for precise fixing of all types of hubs, e.g. toothed gears, running and chain wheels, levers, cams, belt and brake discs, sliding gears, couplings or flanges, on shafts and axles.

- Locking Assemblies Ringfeder are a superior alternative to conventional elbow, wedge, keyway or polygonal connections and offer superior concentricity and resistance to alternating torsion.

5. Genuine and Reputable Supplier of Ringfeder Locking Assemblies: