Candidate List Duty Triggers in Component Level Imports
Candidate List duties trigger when any discrete component article exceeds 0.1 percent SVHC by weight, regardless of aggregate assembly mass.
Homogeneous Material
Meaning
Regulatory classification defines a substance of uniform composition throughout or a mechanical combination that cannot be separated into distinct materials through unscrewing, cutting, crushing, or grinding processes. Compliance engineers evaluate homogeneous material units when certifying plastic assemblies under hazardous substance restrictions like RoHS. Multi-layer film structures and co-moulded elastomer grips represent critical evaluation points where individual layers constitute separate analytical subjects.
The designation ceases to apply when mechanical separation yields discrete sub-components.
Analytical Dissection
Testing laboratories grind or slice plastic parts down to uniform individual layers prior to chemical assaying. Heavy metals such as lead and cadmium are measured inside each single material phase rather than across the entire assembled component. Delamination of co-extruded films isolates specific functional barrier layers for independent spectroscopy.
Micro-drilling extracts samples from encapsulated metallic inserts.
Compliance Risk
Non-compliant flame retardants inside a single inner layer trigger full part rejections during regulatory inspections. Concentrated toxic additives in localized pigment masterbatches fail threshold tests even when diluting resin appears compliant. Sub-tier supplier auditing prevents unverified resin layers from entering assembly lines.
Moulding Integration
Overmoulded thermoplastic elastomers create bonded structures that require precise destructive sectioning for laboratory testing. Mechanical bonding between substrate rigid polymers and soft flexible covers requires microscopic separation tools during sample preparation. Incomplete separation skews chemical concentration readings across adjacent material interfaces.
Testing single phase materials guarantees exact regulatory verification.