SIST EN ISO 19399:2018 PDF

Overview

EN ISO 19399:2017 (ISO 19399:2016) - Paints and varnishes - Wedge-cut method for determination of film thickness (scribe and drill method) - specifies a destructive microscopic method to determine dry film thickness of coatings. The wedge-cut (scribe or drill) creates a controlled damage whose geometric projection is measured with a measuring microscope; film thickness is calculated from the measured base and the wedge-cut angle (t = l · tan α). The method is suitable for most coat–substrate combinations and can resolve single film thicknesses within multilayer coating systems.

Key topics and requirements

• Scope and applicability
  • Destructive method for dry-film thickness measurement.
  • Applicable to single coats and multilayer coating systems where microscopic contrast exists.
  • CEN adoption of ISO 19399:2016 (EN ISO 19399:2017).
• Two methods
  • Method A - wedge-cut scribe (linear scribe flank measured microscopically).
  • Method B - wedge-cut bore/drill (conical bore; concentric circles measured).
• Measurement principle
  • Film thickness calculated using the wedge-cut base (l) and wedge angle (α): t = l · tan α.
  • Instruments may express readings in scale divisions or micrometres; wedge-cut factor (tan α) or divisor is used for conversion.
• Apparatus and microscope limits
  • Measuring microscope with adequate depth of field and scale resolution.
  • Wedge-cut tools with defined flank angles (examples given: 5.7° and 14.0°).
  • Example measuring ranges: up to ~200 µm (α = 5.7°) and up to ~500 µm (α = 14.0°); example absolute resolutions 2 µm and 5 µm respectively.
• Limitations
  • Not suitable or restricted for: very soft/elastic coatings or substrates, very hard (unscribable) substrates, poor visual contrast between coating and substrate, or film thicknesses exceeding microscope depth of field.
• Normative reference: ISO 4618 (terms and definitions).

Applications and users

• Practical applications:
  • Quality control and verification of dry film thickness in paint and varnish production.
  • Determination of single coat thicknesses in multilayer coating systems.
  • Failure analysis and laboratory assessment where destructive measurement is acceptable.
• Typical users:
  • Coatings test laboratories, R&D and QC teams in paint manufacturers, corrosion engineers, inspection bodies, and standards/specification writers.

Related standards

• ISO 4618 - Paints and varnishes: terms and definitions (normative reference used by EN ISO 19399:2017).
• EN ISO 19399:2017 is the CEN-endorsed European version of ISO 19399:2016.

Keywords: EN ISO 19399:2017, ISO 19399:2016, wedge-cut method, scribe and drill method, dry film thickness, paints and varnishes, coating systems, measuring microscope.