3D Geometry (GD&T)

High-precision non-contact 3D geometry measurements

Geometric dimensioning & tolerancing (GD&T) is a system used to define and communicate dimensional requirements on manufactured parts.

Novacam 3D metrology systems scan parts to generate 3D point clouds from which dimensions and GD&T parameters are rapidly calculated.  The systems offer:

  • Measurement precision better than 1 µm
  • High-speed scanning: point-by-point acquisition at 2,100 to 100,000 3D point measurements per second
  • Turnkey GD&T measurement, analysis, and reporting solution with optional purchase of PolyWorks InspectorTM, which Novacam offers as standard option. Alternately, clients have the option to process the data themselves with their own software.
  • Ability to use the same system to for overall 3D surface metrology – measure roughness, chatter, or and/or defects – depending on system configuration
  • Real-time feedback on manufacturing processes: application data is typically forwarded to process control software.
Automated 3D geometry measurements inside a drilled rivet hole.  Shows the diameter measurement, measurement of countersink included angle, angle between countersink and rivet hole wall, and angle between house and countersink axes

Automated 3D geometry measurements inside a drilled rivet hole. The 3D point cloud was analyzed with PolyWorks InspectorTM.

List of 3D measurements and GD&T parameters

The tables below list the types and examples of dimensional measurements and GD&T parameters that may be obtained from 3D point clouds generated by Novacam systems.

    GD&T parameter measurementsExamples
    GD&T characteristicSymbolType of toleranceMeasurements on INTERNAL
    surfaces (inside bores, slots, etc..)
    Measurements on EXTERNAL surfaces
    • Axial straightness of bore, tube or barrel IDs (blog)
    • Axial straightness of cylinder, tube, or barrel ODs
    • Area in between NGV blades (video)
    • Heat exchanger slot surfaces
    Circularity (roundness)
    Profile of a lineProfile
    • Profiles airfoils – leading & trailing edge (video)
    • Profiles of turbine and stator blades (video)
    Profile of a surface
    • Incidence angle of cooling holes with respect to datum of turbine blade surface (application note)
    • Angularity of bearing ID surfaces
    • Angularity of bearing OD surfaces
    • O-ring groove: perpendicularity of side wall to back wall
    • Heat exchanger slot surfaces
    • Valve body bores (video)
    • Inside-outside, inside-inside, outside-outside
    • Rivet hole & rivet countersink (application page)
    Circular runoutRunout
    Total runout

Capabilities for 3D geometry measurement

Novacam metrology systems offer:

  • Non-contact, collinear scanning: the emitted and received light signals travel along an identical path. This means that high-aspect-ratio features such as slots, cross-holes or undercuts are easy to measure
  • User-configurable scanning protocol (point density, spiral pitch, scanning path).  Users adjust scanning paths and scan point densities to satisfy their metrology requirements while minimizing their inspection cycle time.
  • Customizable scan definitions (comprising scanning and reporting) that may be saved for later reuse.
  • Option to provide measurement data to data loggers and SPC (statistical process control) software.

Typical scanning paths for bore ID measurement. Measurements are acquired in a point-by-point manner at a rate of up to 100,000 3D points per second.

Advantages of Novacam metrology systems’ design

Novacam metrology systems offer many advantages to our clients thanks to a unique combination of LCI technology and fiber-based design of the system. These advantages include:

  • Configuration versatility for both benchtop and in-process inspection
  • Support for automation
  • Ability to acquire long profiles
  • Ability to measure inside small-diameter tubes, bores, etc.  See inspection in hard-to-reach spaces
  • Ability to measure surfaces with steps, grooves, channels, holes, and other high-aspect-ratio features
  • Ability to scan surfaces that are reflective or nonreflective, smooth or rough, stationary or moving
  • Ability to measure GD&T even in extreme temperatures or in radiation. See inspection in hostile environments.

Novacam fiber-based optical probes come in many designs and models, which include standard or small-diameter (shown), as well as rotational scanners and galvo scanners – to satisfy the majority of high-precision inspection applications.

Examples of Novacam fiber-based optical probes – standard and small-diameter.

Cost-effective in-line inspection

Novacam fiber-based probes and scanners enable the integration of inspection directly into production process. They can be mounted:

  • Above a continuously moving web
  • Adjacent to a rotating part (cylinder, shaft, etc.)
  • Inside a machining center
  • On robotic arms.

With continuous monitoring and real-time feedback on a manufacturing processes, dimensional variations and out-of-spec characteristics are identified promptly,  helping avoid or minimize losses, while preserving quality and yields.

Novacam rotational scanner RS2 on a robotic arm inspects bores in an engine cylinder block.

Probe multiplexing for additional return on investment (ROI)

Multiple probes may be multiplexed to one interferometer with the addition of an optical switch. With  this setup, probes take turns acquiring measurements on several aspects of a production line.

Do you need to measure your dimensional geometry precisely and efficiently?

Related links

 Contact us or request free sample analysis to see if Novacam 3D metrology systems are suitable for your 3D geometry or GD&T measurements