Overview
IEC 62899-202-5:2018 defines a standardized mechanical bending test for evaluating the electrical behavior of a printed conductive layer on an insulating (flexible) substrate under repeated deformation. The standard describes the sliding-plate bending test method used in printed electronics to assess conductivity degradation and long-term reliability of conductive inks and printed conductive films.
Key topics and requirements
- Scope: Mechanical bending test for printed conductive layers on flexible insulating substrates (conductive ink / conductive film).
- Test method: A sliding plate (reciprocating linear motion) bends the sample into a half-circle between two plates, producing cyclic bending/unbending (sliding plate test). Electrical properties are measured through conductive metal grips.
- Specimen geometry: Rectangular specimens for uniform strain. Standard specimen sizes (effective sample length × width) include:
- Type A: 30 × 10 mm
- Type B: 30 × 30 mm
- Type C: 50 × 10 mm
- Type D: 50 × 25 mm
- Type E: 80 × 50 mm
- (Alternatively, any specimen with length ≥ 4× the linear motion length)
- Apparatus: Two rigid, smooth plates with adjustable gap; one plate moves linearly (0–30 mm). Grips must be conductive for electrical connection; plates are typically insulating (resin, polycarbonate, mono-cast nylon).
- Environmental conditions: Standard measurement atmosphere as defined in the standard series - temperature (23 ± 2) °C, relative humidity (50 ± 10) %, air pressure 86–106 kPa.
- Measurements and analysis: Electrical resistance/conductivity is tracked during cycling; bending strain is characterized (Annex A) using the relation ε = (h + t) / 2r (nominal bending strain as a function of substrate thickness h, printed film thickness t, and curvature radius r). Reporting guidelines and data-analysis procedures are specified.
Applications and users
- Practical uses:
- Reliability testing and lifetime/ fatigue evaluation of printed conductive tracks and electrodes.
- Quality control and supplier qualification of conductive inks and printed films.
- Comparative R&D for ink formulation, post-treatment, and substrate selection.
- Design validation for flexible electronics: wearables, flexible displays, RFID antennas, sensors, and printed interconnects.
- Typical users:
- Conductive ink manufacturers and material suppliers
- Printed electronics manufacturers and OEMs
- Independent test laboratories and certification bodies
- R&D teams in flexible electronics and materials science
Related standards
- IEC 62899-202:2016 - Printed electronics: Materials - Conductive ink (normative reference)
- Other parts of the IEC 62899 series and relevant testing standards (e.g., ISO 527-3 referenced for specimen dimensions)
Keywords: IEC 62899-202-5:2018, printed electronics, conductive ink, conductive layer, mechanical bending test, sliding plate test, bending strain, flexible substrate, reliability testing.