Sudden movements, vibrations, or whining noises during turning are common problems for excavator operators, crane operators, forklift drivers, and platform operators. These symptoms are often due to the so-called. the stick-slip effect - a motion that occurs in rotating joints when friction varies.
The stick-slip effect occurs when two surfaces slide against each other under varying friction conditions. The movement becomes irregular, alternating between sticking (“stick”) and slipping (“slip”). This often happens in machines where static friction exceeds dynamic friction. The system “sticks” until the applied torque surpasses the frictional resistance, causing a sudden release of movement—resulting in unwanted vibration or irregular motion.
In large rotating machinery, stick-slip can occur due to the system's elasticity and the characteristics of the drive design. For example, a worm gear with low efficiency or inadequate lubrication can trigger the effect. At its core, it is a friction-related issue, often amplified by design flaws or manufacturing imperfections.
Consequences for machine and operator
Stick-slip has several negative effects:
- Irregular or abrupt movements generate shock loads that accelerate wear on bearings, gears, and fasteners, ultimately reducing the system’s service life.
- The problem leads to downtime, troubleshooting and loss of production.
- The machine becomes more difficult to maneuver precisely, which poses a safety risk, for example when a load oscillates during jerky movement.
Technical solutions to the problem
The problem can be technically countered:
- Proper lubrication reduces the difference between static and dynamic friction.
- Smart worm gear with double threads provides higher efficiency and smoother movement.
- Rigid and precisely assembled structure reduces unwanted elasticity.
Advantages of High Quality Slew Drive
The most effective solution is often to switch to a high-quality Slew Drive. Bengtssons Maskin offers such devices, manufactured in collaboration with IMO GmbH.
These are distinguished by:
- High load capacity and torque strength
- Efficient worm gear design with high efficiency
- Closed design with custom lubrication
- Hardened materials in shells and bearings
Summary-
The result is smooth, precise and safe rotation without stick-slip, even under heavy loads. The operator gets better control and the equipment gets longer life with reduced maintenance.
By investing in technical solutions at the source, the problem can be eliminated. Contact us of Bengtssons Maskin for advice and the right Slew Drive solution for your needs.
