Feiljustering

Feiljustering, or misalignment, is the condition in which two or more connected parts are not positioned or oriented as intended. It is commonly discussed in mechanical engineering, rotating machinery, and optical systems. Misalignment can arise at installation or develop during operation.

The main types are angular misalignment, where shafts diverge in angle, and parallel (offset) misalignment, where shafts are parallel but displaced along their axes. In practice, many systems exhibit a combination of both.

Causes include improper installation, premature wear, thermal expansion and contraction, mounting looseness, and changes in loaded condition. Consequences include elevated bearing and gear loads, increased vibration and noise, accelerated wear, reduced efficiency, and, in extreme cases, equipment failure.

Measurement and correction: alignment is typically determined with machinist's straightedge, dial indicators, or laser-based alignment tools. The process involves aligning shafts and couplings to specified tolerances, checking runout, and compensating with shims, adjustable couplings, or repositioning components. For rotating equipment, thermal growth and running conditions should be considered; hot-cold alignment can differ.

Prevention: design components with adequate tolerances, use suitable mounting hardware, perform periodic alignment checks, and implement monitoring. Regular maintenance reduces the risk of misalignment-related failures.