3D Scanning
High-density point clouds for inspection, reverse engineering and digital twins - handheld, arm-mounted and stand-alone systems compared, independently.
How it works
3D scanners capture the surface of a part as a dense cloud of XYZ points, typically hundreds of thousands to tens of millions per capture. Laser-line scanners project a stripe and triangulate its position with one or two cameras. Structured-light scanners project a sequence of fringe patterns and reconstruct the surface photogrammetrically. Handheld systems (Creaform HandySCAN, Artec Leo, Zeiss T-SCAN) add real-time positioning via reference targets or SLAM.
Typical accuracy
Handheld laser scanners are typically specified at 20-40 microns accuracy with a volumetric uncertainty of ~20 microns + 40 microns/metre. Fixed structured-light systems (ATOS, Zeiss COMET) reach 5-15 microns on well-conditioned surfaces.
Applications
- Full-surface inspection against CAD (colour-map deviation)
- Reverse engineering of legacy or organic parts
- Digital twins and as-built records
- Tooling and fixture proving
- Composite and sheet-metal inspection
- First-article inspection where GD&T needs full-surface evidence
Strengths
- • Full-surface capture - not just discrete points
- • Fast for complex, freeform or organic geometry
- • Non-contact - safe for soft, delicate or unstable parts
- • Colour deviation maps communicate results to non-metrologists
Limitations
- • Shiny, transparent or dark surfaces need spray or coating
- • Sub-10 micron accuracy needs structured light and a stable environment
- • Point-cloud data volumes stress older PCs and storage
- • Feature-based GD&T from scan data needs mature software workflows
Handheld laser scanning
Handheld laser scanners (Creaform HandySCAN BLACK / MAX, Zeiss T-SCAN hawk, Artec Ray II) have become the pragmatic default for shop-floor inspection of parts from 100 mm to several metres. Modern blue-laser and multi-stripe systems reach volumetric uncertainties in the 20-60 micron range without a rigid setup, using stick-on reference targets or dynamic referencing.
When scanning is - and isn't - metrology
A dense point cloud is not automatically a measurement. Real metrology requires probing strategy, uncertainty statements, alignment to a defensible datum reference frame and GD&T evaluation. Modern software (PolyWorks|Inspector, GOM Inspect, Control X) fully supports this - but only if the user drives it that way rather than treating scans as pretty pictures.
Buying considerations
- Handheld vs fixed vs arm-mounted - matched to part size and volume
- ISO 10360-8 (optical distance sensors) certification
- Multi-material capability without matting spray
- Reference-target vs marker-less workflows
- Software: PolyWorks, GOM Inspect, Geomagic Control X, VXelements
FAQs
Can 3D scanners replace our CMM?+
For freeform parts, large parts and full-surface inspection, often yes. For tight prismatic tolerances under 10 microns, no - CMM tactile scanning remains the right tool.
Do we need to spray the parts?+
Not with modern blue-laser or multi-stripe handhelds on most metallic finishes. Highly reflective, transparent or black surfaces still benefit from a light matting spray such as AESUB Blue that evaporates without cleaning.