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Volume loss

Volume loss describes the amount of material lost on a surface due to abrasion, erosion or other types of wear. Novacam low-coherence profilometers measure volume loss directly and with micron precision as follows:

  1. The worn region of the sample and the intact region around it are scanned.
  2. A reference plane is constructed for the intact surface.
  3. Novacam Volume Loss Application software calculates volume loss from the differences between the interpolated reference plane and the actual worn surface.

3D rendering of a surface (25 by 50 mm) worn away by abrasion

3D rendering of a surface (25 by 50 mm) worn away by abrasion

The surface measurements form a 3D image for easy visual analysis of the surface wear. Materials may be reflective or nonreflective, smooth or rough, stationary or moving. See more on what we can measure.

Surface acquisition with fiber-based probes

Because Novacam profilometers scan surfaces with fiber-based optical probes, they offer significant advantages:

  • They acquire long profiles: probes acquire surface data one point at a time, at high speeds of 1 to 30 kHz and higher. No need for time-consuming surface tiling.
  • They offer configuration versatility for benchtop or in-process inspection. Probes are mounted onto a benchtop or inline motion mechanism suitable for each application: X-Y table, galvo-scanner, rotational scanner, robotic arm, etc.
  • Probes can work far from profilometer enclosure, as far as 1 km away, without signal degradation.
  • Small probes reach inside to inspect interiors of small-diameter tubes, bores, etc. See inspection in hard-to-reach spaces.
  • Rugged probes perform even in extreme temperatures or in radiation. See inspection in hostile environments.
  • Collinear probes easily inspect surfaces with grooves, channels, steps and holes - no triangulation angle is necessary. See inspection of high-aspect-ratio features.

Novacam standard and small-diameter fiber-based optical probes

Novacam standard and small-diameter fiber-based optical probes

Dimensions of scanned objects

Fiber-based profilometers scan objects as small as few microns in width; there is no upper limit on object size.

Example: measuring surface wear on a rotating 1.2m-diameter metal cylinder

One type of electric commutator is a rotating 1.2m-diameter metal cylinder. The curved surface of the cylinder gets worn away by abrasion from metal brushes.To acquire and characterize the damaged commutator surface:

1) the cylinder is rotated around its horizontal axis (see green path on photo), while the optical probe is moved back and forth along the cylinder side (yellow path).

Optical probe scans (1.2m-diameter) motor commutator for surface wear and volume loss caused by abrasion

2) The acquired long profile data is programmatically “unwound” to produce a flattened image of the commutator surface, showing wear from brush abrasion (see below).

Flattened surface of the 1.2m-diameter motor commutator shows wear from brush abrasion

Flattened surface of the 1.2m-diameter motor commutator shows wear from brush abrasion