Scratch Resistance Tester – QualiHSA™ SRT
The QualiHSA™ SRT Scratch Resistance Tester evaluates the mechanical durability of protective coatings by moving a
hardened steel needle across the coated surface under a controlled 10 N force. The test determines whether
insulation coatings can withstand scratching without compromising their protective function. It is used by
electrical safety laboratories to assess accessible appliance surfaces and coated printed circuit boards where the
coating provides supplementary or reinforced insulation.
A PLC-controlled stepper motor regulates needle movement, including travel speed, scratch length, and spacing. The
integrated 7-inch color touchscreen allows operators to configure and save test parameters for consistent repeat
testing. Once the settings are established, the complete test sequence can be initiated with a single button.
The testing needle features a 40° conical profile with a rounded, polished tip radius of R0.25 mm. It is positioned
at an angle of 80° to 85° relative to the specimen surface and applies an axial force of 10 N ± 0.5 N. Scratch speed
is adjustable from 0.1 mm/s to 30 mm/s, with an accuracy of ±1%, accommodating the standard-specified speed of 20
mm/s. An automatic 90° specimen indexing mechanism enables perpendicular scratch patterns in both vertical and
horizontal directions without requiring manual repositioning.
Operators can program scratch length, spacing, and the number of repetitions directly through the touchscreen. With a
working area of at least 200 mm × 200 mm, the instrument accommodates a wide range of coated specimens. Its
controlled testing process helps compliance engineers reproduce the required scratch pattern before conducting the
subsequent electric strength test.
The QualiHSA™ SRT is suitable for manufacturers of household appliances, power supplies, and information technology
equipment that need to evaluate conformal coatings and printed circuit board finishes. Available power
configurations include 110 V, 60 Hz and 220 V, 50 Hz, supporting installation in North American laboratories.
Scratch Resistance Tester – QualiHSA™ SRT Applications
The QualiHSA™ SRT is designed for coating evaluation programs in which surface layers contribute to electrical
insulation and must retain their protective properties after mechanical contact. Its testing capabilities cover
coated printed circuit boards, painted equipment enclosures, and accessible plastic components.
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Household Appliance Manufacturing: Evaluates protective coatings on accessible appliance components and
enclosures to determine whether scratching could expose energized conductors.
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Printed Circuit Board Coating Validation: Assesses conformal coatings used to provide supplementary or
reinforced insulation between conductive components on printed circuit boards.
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Power Supply and Charger Production: Checks whether insulating films on coated circuit boards inside compact
adapters remain intact following handling and assembly operations.
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IT and Communication Equipment: Supports coating durability assessments for equipment subject to information
technology and audio/video product safety requirements.
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Safety Certification Laboratories: Provides repeatable scratch testing procedures that form part of the
evaluation process before the electric strength test, with results documented in compliance records.
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Coating and Ink Suppliers: Enables comparative testing of different conformal coating formulations using
consistent needle geometry and applied force.
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Motor Drive and Control Assemblies: Evaluates insulating coatings on circuit boards and coated busbar
coverings used in power electronic assemblies.
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Incoming Quality Control: Helps quality teams assess incoming batches of coated circuit boards supplied by
contract manufacturers before they proceed to final assembly.
Applicable Standards
The QualiHSA™ SRT supports coating durability assessments required by electrical and electronic equipment safety
standards. These procedures examine whether insulating coatings on accessible surfaces and printed circuit boards
can withstand mechanical scratching without losing their intended insulation function. The instrument provides
controlled needle geometry, a defined 10 N test force, adjustable travel speed, and programmable scratch positioning
to carry out the specified evaluations.
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IEC 60335-1 – Household and Similar Electrical Appliances: Safety – Part 1: General Requirements: Clause 21.2
specifies scratch testing of coatings on household appliances and similar electrical equipment to assess
their resistance to mechanical damage.
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IEC 60950-1 – Information Technology Equipment: Safety – Part 1: General Requirements: Clause 2.10.8.4
addresses protective coatings applied to printed circuit boards, including their ability to maintain the
required insulation protection following the prescribed scratch test.
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IEC 62368-1 – Audio/Video, Information and Communication Technology Equipment: Part 1: Safety Requirements:
Annex G covers the abrasion resistance evaluation of coating layers used in equipment covered by this safety
standard.
Scratch Resistance Tester – QualiHSA™ SRT Key Features
The QualiHSA™ SRT provides automated control over the critical variables that influence scratch testing, including
needle speed, applied force, and scratch positioning. Test configurations can be entered and stored through the
touchscreen, allowing operators to reproduce the same testing conditions across multiple specimens.
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PLC Control with 7-Inch Color Touchscreen: Provides a centralized interface for setting scratch speed,
length, spacing, and repetition count. Stored configurations can be retrieved for subsequent tests.
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Stepper Motor Drive: Maintains controlled needle movement throughout the testing stroke, with scratch speed
accuracy of ±1%.
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Standard Needle Geometry: Uses a hardened steel needle with a 40° conical point and an R0.25 ± 0.02 mm
polished tip, corresponding to the published test methods.
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Fixed 10 N Loading: Maintains an axial needle force of 10 N ± 0.5 N to ensure consistent mechanical loading
during each scratch.
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Wide Speed Range: Offers adjustable travel speeds from 0.1 mm/s to 30 mm/s, covering the specified 20 mm/s
test speed as well as slower speeds for exploratory testing.
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Automatic 90° Indexing: Rotates the specimen in both directions to produce vertical and horizontal scratch
patterns without removing or reclamping the sample.
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Large Working Area: Provides a minimum scratch testing area of 200 mm × 200 mm for accommodating full-size
printed circuit boards and enclosure panels.
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Programmable Scratch Pattern: Allows scratch lengths from 5 mm to 200 mm and spacing adjustments from 0.2 mm
to 200 mm. The repetition count can also be configured according to the test procedure.
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Adjustable Scratch Angle: Supports needle inclination settings between 80° and 85° to reproduce the
positioning illustrated in the applicable test method drawings.
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One-Button Operation: Starts the complete programmed scratch sequence with a single command, reducing manual
intervention and minimizing variation between test runs.
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Dual Voltage Build: Available with 110 V, 60 Hz or 220 V, 50 Hz power supplies. Other electrical
configurations can be provided upon request.
Theory and Method
The scratch resistance test determines whether an insulating coating can maintain its electrical protective function
after sustaining mechanical surface damage. Rather than relying on visual inspection alone, the procedure
deliberately subjects the coating to controlled scratching at locations where the electrical potential difference
between conductive components is greatest. Five pairs of conductive parts are subjected to the prescribed scratch
pattern. Each scratch must remain at least 5 mm away from adjacent scratches and 5 mm from the specimen edge.
Following this mechanical assessment, an electric strength test establishes whether the remaining coating can still
withstand the required working voltage.
Needle geometry directly influences the stress applied to the coating. Its 40° conical profile concentrates the axial
force of 10 N onto a very small contact area, typically measuring only a few hundred micrometers across. This
concentration produces substantially higher localized pressure than a flat-ended indenter. The polished tip, rounded
to a 0.25 mm radius, provides a defined contact geometry and helps ensure that test results reflect the coating's
mechanical properties rather than variations caused by differences in needle sharpness or wear. Maintaining the
needle inclination between 80° and 85° encourages a consistent forward scratching action while preventing excessive
penetration and chatter.
Travel speed is another important factor because polymer coatings exhibit viscoelastic behavior, meaning their
mechanical response changes with deformation rate. As strain rate increases, these materials become stiffer.
Maintaining a controlled needle speed of 20 mm/s establishes a consistent deformation rate throughout each scratch,
allowing groove depth to be evaluated in relation to the coating's properties rather than variations in operator
technique. The stepper motor drive maintains speed accuracy within ±1% over the full travel distance, while the PLC
reproduces the programmed scratch path for every pass.
For specimens requiring scratches in perpendicular directions, the automatic 90° indexing mechanism changes the
specimen orientation between passes. This arrangement allows cross-hatched scratch patterns to be completed within
the same setup, eliminating the need to release and reposition the specimen manually.
Scratch Resistance Tester - QualiHSA™ SRT Technical Specifications
| Parameter |
Specification |
| Voltage |
110 V, 60 Hz or 220 V, 50 Hz (other supplies on request) |
| Control System |
PLC with 7-inch color touchscreen |
| Drive System |
Stepper motor |
| Stations |
Single station |
| Needle Material |
Hardened steel |
| Needle Apex Angle |
40° |
| Needle Tip Radius |
R0.25 ± 0.02 mm |
| Applied Load |
10 N ± 0.5 N |
| Scratch Angle |
80° to 85° |
| Scratch Speed |
0.1 mm/s to 30 mm/s, adjustable |
| Scratch Speed Accuracy |
±1% |
| Scratch Length |
5 mm to 200 mm, operator set |
| Scratch Spacing |
0.2 mm to 200 mm, operator set |
| Maximum Scratch Range |
≥ 200 mm × 200 mm |
| Continuous Repeat Scratches |
Programmable |
| Number of Scratches |
Limited only by scratch spacing and travel range |
| Specimen Indexing |
Automatic 90° rotation in both directions |
| Operation Mode |
One-button start |
