Toleranssitaso

Toleranssitaso is a term used in engineering and metrology to describe the permissible deviation range around a nominal dimension. It defines how far an actual part size may differ from the intended specification while still being considered acceptable for its function. The toleranssitaso is a key part of quality control, product interchangeability and manufacturing feasibility.

Toleranssitaso is typically specified on technical drawings as either bilateral or unilateral tolerances. A bilateral tolerance indicates a symmetric allowed deviation around the nominal size, expressed as plus and minus values (for example, 50.00 mm ± 0.05 mm). A unilateral tolerance allows deviation only in one direction (for example, 50.00 mm +0 / -0.10 mm). The range between the upper and lower limits constitutes the tolerance zone, and the actual dimension must lie within this zone.

In practice, toleranssitaso is influenced by factors such as the required function, fit with mating parts, manufacturing capabilities, cost considerations, and measurement accuracy. Standards and conventions, such as the ISO 286 system of limits and fits, guide the assignment of tolerances to ensure compatibility and predictable performance across parts and assemblies.

Verification involves metrological methods and gauges to ensure parts meet the specified toleranssitaso. Insufficient tolerances can increase manufacturing costs and reject rates, while overly loose tolerances can compromise performance. Understanding toleranssitaso allows designers to balance function, manufacturability, and quality.