Eliminating squeaking noises in linear drives

1. Introduction

Whether Screw Jacks, Electric Cylinders, or Linear Chains – squeaking noises during operation are not only irritating, but often an early warning sign of wear or improper installation. Such noises are typically caused by friction between components when lubrication is insufficient or when the system is mechanically misaligned or under stress.

Below, we outline the most common causes of squeaking noises and how to eliminate them permanently.

2. Why do squeaking noises occur?

Squeaking usually occurs when two dry surfaces slide against each other under load. In linear drive systems, this may involve the lead screw and nut, guide bushing and piston rod, or chain links within a guide channel. Unintended mechanical stresses or lateral forces can also increase contact pressure between components – resulting in audible noise.

3. Typical Causes

Squeaking generally occurs when two surfaces move against each other without an adequate lubricant film. Worn components can also produce squeaking noises before failure occurs. The source of the problem may arise at any friction point within the system:

3.1 Insufficient lubrication

If lubricant has not been applied for an extended period or lubrication points are no longer accessible, metal-to-metal contact occurs, resulting in the characteristic squeaking sound. Improper engagement of the lead screw within the nut can also cause friction without sufficient lubrication.

3.2 Mechanical stress (System Binding)

Mechanical binding often occurs when the lifting element has not been installed free of stress or when insufficient degrees of freedom are provided for thermal expansion. Temperature changes can increase internal stress, leading to higher contact pressure at guide bushings (typically located in the housing) – another common cause of squeaking.

3.3 Lateral forces

Lateral forces act perpendicular to the direction of movement and increase surface pressure within guides or the screw nut. Increased pressure in the guide bushing results in excessive contact and friction.

4. Corrective measures

4.1 Check and renew lubrication

Ensure that all moving components are lubricated regularly and sufficiently. In cylinder systems, lubrication is often performed via a grease nipple when the piston rod is fully extended. Note: Over-lubrication is generally not technically critical, but it may cause contamination or increase the required drive force of the lifting element.

4.2 Follow installation guidelines

Never use a fixed–fixed bearing arrangement in screw-driven systems. The lifting element must be able to expand axially due to temperature changes. Improper bearing arrangements can lead to internal stress.

4.3 Relieve system binding through testing

Unintended mechanical stress often becomes visible when one mounting point is loosened. If the system “jumps” into a relaxed position, it was previously installed under stress. In such cases, check installation tolerances and the manufacturer’s bearing specifications.

4.4 Identify and minimize lateral forces

Typical sources of lateral forces include:

1. Inaccurate steel structures
2. Eccentric loads
3. Wind loads
4. Misaligned or skewed roller guides

Use precision leveling instruments or laser alignment systems when compensating for inaccurate steel structures. In applications with highly variable lateral forces, consider selecting a stronger guide system or an alternative design.

5. Additional note: Targeted noise localization

In complex systems, it can be helpful to manually reproduce the noise with the system powered off – for example, by moving it slowly by hand. This makes it easier to identify the affected component (lead screw, bushing, guide, etc.). Acoustic sensors and industrial stethoscopes are also increasingly used in maintenance applications.

6. Conclusion

Squeaking noises in linear drive systems are not merely a nuisance, they are almost always an indication that something is wrong within the system. Common causes such as insufficient lubrication, impermissible mechanical stress, or lateral forces can usually be identified with experience and corrected quickly. Early intervention not only prevents consequential damage and unplanned downtime, but also ensures long-term reliable and quiet operation.