RJL Micro & Analytic GmbH
Residual contamination and component cleanliness

«Particles are annoying»

For reliability and lifetime of components, it is crucial to avoid contaminant particles.
Hence, technical cleanliness is a quality feature that has to be ensured permanently in order to control cost.

Residual contamination - what is it?






Residual contamination consists of solid particles and
soluble substances that persist on the surface of the
component after the final step in manufacturing. Such
residual dirt is either introduced through parts supplied
externally or it is produced during machining. The dirt particles get into engines or transmissions. Especially
hard inorganic particles cause severe damage and
reduce the lifetime of the product.


Technical cleanliness - what is it?






Technical cleanliness is the status of a component with
respect to the amount of contamination on the surface.
Common measures to quantify the cleanliness are mass of
the contaminants as well as number, size and composition
of the residual dirt particles. In general, the customer will
specify contamination limits. The supplier has has to
maintain these levels and document them regularly
by means of contamination analyses.


Typical appearance of residual contaminants







































Test methods






Some analytical techniques are essential:


  • extraction of the contaminants
  • gravimetry (weighing of the contamination mass)
  • granulometry (particle number, size and composition)



View test methods in details  Cleanliness Analysis


Test directives






For cleanliness testing, a number of directives apply:


  • ISO-16232, VDA-19 (automotive parts) 
  • ISO-4405/-4406/-4407 (oils and hydraulic liquids)
  • customer specific directives



Overview of test directives  VDA-19, ISO-16232 and Co.


© RJL Micro & Analytic GmbH, Im Entenfang 11, 76689 Karlsdorf-Neuthard, Germany (2007-18) - Imprint - Sitemap


Accredited Contract Laboratory Aspex Bruker microCT Component Cleanliness Contamination Analysis E2V EDX Gunshot Residue GSR in-vivo ISO-16232 ISO-17025 ISO-4405 ISO-4406 ISO-4407 Kubtec Laser Microscopy Material Analysis Micro-CT MicroQuick Microtomography Millbrook MiniSIMS Nano-CT Nanotomography Nanophoton Oil Cleanliness Analysis Particle Analysis Particle Scanner Particle Typing PSEM Radiography Raman Microscopy Residual Dirt Analysis X-Ray Inspection Analysis SAI Scanning Electron Microscopy SEM-EDX SGX Sensortech SIMS-TOF SkyScan South Bay Technology Steel Inclusion Analysis Technical Cleanliness Time-Of-Flight VDA-19 Non-Destructive Testing