Roughness quality control

Hip prosthesis roughness

Medical Authorities requires roughness measurement according to ISO Standard for human implementation of hip prosthesis. Lyncée Tec has developed a system for their automated measurement with manual loading of both cup and ball hip spherical prosthesis:. It enables:

  • Measurement in production environment with external vibrations due to surrounding presence of CNC and polish machines
  • Quality control of roughness with very low Ra acceptance threshold
  • Implant diameters form 1cm to 8cm
  • Non-contact measurement to avoid any scratch and surface contamination

Successful comparison of DHM measurements has been carried out on hip prosthesis characterized by METAS (The Swiss Federal Institute of Metrology).


  • Material:
    • Stainless steel hip prostheses
    • Diameter from 1 cm to 8 cm
  • Typical Ra threshold: 1 to 6 nm
  • Automated Process
    • Manual prosthesis loading
    • Bar code reading for lot authentication
    • Automation of cap and ball orientation according to dimension
    • Automated focalization
    • Scan of the surface
    • Automated report on the lot on a secure server
  • Instrument:
    • DHM® R-1000
    • Stage with 5 motorized axis: XYZ, θ, ϕ
  • Software
    • TCP/IP remote to control a network of 3 DHM® by an automated supervision system for acquisition and data management
    • Customized user interface dedicated to the application and adapted to production operators
  • Time scale for the full process: <30 s
  • Magnification: 10x

Example of dedicated hardware and software for automated roughness measurement

Bearing Ball roughness

Bearing balls roughness influences wear behavior, especially when made out of ceramics. DHM® are capable of characterizing them very efficiently:

  • DHM® provide full field of view measurement instantaneously, without any scanning. It enables on-flight measurements, without stopping the ball rotation.
  • Use of Ultra High Numerical aperture objective enables to measure balls of small radius.
  • Infinite depth of focus provides a sharp focus over the whole surface thanks to digital focusing.


  • Material:
    • Stainless steel and ceramic balls
    • Diameter down to 0.4 mm
  • Typical Ra threshold: 10 nm
  • Automated Process
    • Ball rotation
    • Automated OK/NOK decision
  • Instrument:
    • DHM® R-1000
  • Software: customized user interface realized using the Software Development Kit
  • Time scale for the full process: <10 s
  • Magnification: 10x or 20x

3D measurement of a bearing ball