RoHS Testing for Idler Pulley: Buyer Checklist
RoHS testing for idler pulley programs is a homogeneous-material control task, not a one-time finished-part checkbox. Buyers need evidence for every material that could contain restricted substances: the pulley wheel substrate, coating or passivation, bearing grease, seals, plating, adhesives, threadlockers, labels, polymer caps, sleeves, bags, and any packaging supplied with the sellable item. A credible supplier should be able to trace each material lot to a controlled specification, approved source, test method, and report that applies to the finished article being purchased. Driventus is an independent aftermarket manufacturer; brand names are referenced for fitment only. For procurement, quality, and compliance teams, the practical target is conformity with RoHS Directive 2011/65/EU as amended by (EU) 2015/863, with REACH SVHC documentation kept aligned. This guide explains what to sample, which EN IEC 62321 methods to request, how to read detection limits and conformity statements, and which supplier controls should be in place before release.
What Parts of the Assembly Need Checking
RoHS applies at the homogeneous material level. That means buyers should not rely on the finished pulley label, a broad supplier declaration, or the outer carton alone. A homogeneous material is one that cannot be mechanically separated into different materials by actions such as unscrewing, cutting, crushing, grinding, or abrasion. In an idler pulley assembly, the wheel, finish, bearing, seal, grease, cap, label, and packaging may each need their own evidence, even when they are sold under one part number.
For an idler pulley, the usual RoHS risk points are:
- Steel or aluminium wheel substrate, including any alloying or free-machining additives
- Zinc plating, nickel plating, passivation, trivalent or legacy chromate conversion coating, anodising, e-coat, powder coat, wet paint, or phosphate coating
- Bearing steel, bearing cage material, internal grease, rust preventive oil, and bearing seal material
- Grease, anti-corrosion compound, and assembly lubricant applied after bearing installation
- Rubber or polymer seals, dust shields, O-rings, isolators, and vibration-damping elements
- Plastic dust cap, protective cap, spacer sleeve, insert, or shipping plug, if fitted
- Adhesives, threadlockers, ink markings, pad printing, labels, and temporary protective films
- Polybags, blister packs, trays, sleeves, labels, and retail or service packaging supplied as part of the sellable item
The highest-risk items are often the small material systems around the machined body, not the metal pulley itself. Hexavalent chromium can be associated with older yellow or clear chromate conversion coatings and some passivation systems. Lead or cadmium may appear in certain pigments, stabilisers, free-cutting alloys, legacy plating processes, or contaminated coating baths. PBB, PBDE, and the four RoHS phthalates are more likely to show up in flexible polymer parts, caps, sleeves, labels, or packaging than in the pulley wheel. Bearing grease and seal compounds also need explicit review because a change in lubricant thickener, additive package, or elastomer grade may not be visible at incoming inspection.
A strong report should identify the tested material family and state whether the result covers the exact finish, cap resin, seal compound, grease, label stock, and packaging used on the production lot. If the supplier changes a coating bath, bearing vendor, grease grade, cap material, label stock, packaging vendor, or subcontracted finishing source, the earlier report may no longer support release. For sourcing teams, the key question is not just “is the part compliant?” It is: which homogeneous materials were verified, by which EN IEC 62321 method, against which drawing or specification revision, and on what lot date?
Build a Sampling Plan That Matches Risk
A useful plan for rohs testing for idler pulley starts with the supply chain, not the lab order. First map the bill of materials, identify the finish and polymer families, and decide which materials need XRF screening, confirmatory wet chemistry, supplier declaration review, or upstream material certificates. The plan should reflect part criticality, supplier maturity, material-source stability, destination market, and the cost of a nonconformance after shipment.
A practical sampling plan should include the following steps:
1. Test first-article or PPAP-equivalent samples before commercial release. 2. Re-test after any change to grease, plating, passivation, seal, cap, adhesive, ink, label, bag, tray, or carton material. 3. Pull samples from actual production or mixed production lots, not only one hand-selected approval sample. 4. Separate metal, polymer, coating, lubricant, and packaging questions so the lab can prepare each material correctly. 5. Keep the test scope aligned to the purchase specification, drawing revision, bill of materials, coating specification, and approved supplier list. 6. Record the purchase order, part number, revision, lot code, production date, cavity or batch reference, bearing batch, and subcontractor finish batch where available. 7. Define escalation rules for inconclusive screens, results near the legal limit, inconsistent supplier declarations, or mismatched sample identities.
Many buyers use XRF to screen accessible metal and coating surfaces, then confirm suspicious or borderline results with wet chemistry under EN IEC 62321. XRF is practical for lead, cadmium, mercury, total chromium, bromine, and some coating checks, but it has limits. It may not reliably characterize thin or layered coatings, inaccessible bearing grease, small elastomer seals, mixed plastics, or low-mass labels. It also reports total chromium rather than hexavalent chromium unless a specific Cr(VI) method is used, which is critical for passivation and conversion-coated surfaces.
For polymers and soft materials, ask the lab to test the actual cap, seal, label, sleeve, bag, or packaging resin as a separate homogeneous material. Phthalate testing normally requires solvent extraction and chromatographic analysis rather than a metal-focused screen. For grease and lubricants, confirm that sample mass, extraction, and preparation are suitable for the restricted substances being evaluated. If a lab grinds the whole assembly together or tests a composite sample without separation, a compliant result may not prove compliance at the homogeneous-material level because dilution can hide a nonconforming small component.
Traceability is the backbone of the sampling plan. Each sample should connect to the purchase order, drawing or catalog reference, production lot, supplier batch, inspection record, and packing record. When traceability is weak, the report becomes only a snapshot, not reliable release evidence. For repeat orders, buyers can reduce routine testing only when the supplier has stable approved sources, documented change control, clean lot history, and a declaration that the material stack has not changed since the last valid report.
How to Read the Lab Report
A useful RoHS report should name the applicable standard, sample ID, test method, tested material, reporting limit, measured result, legal threshold, and conformity conclusion. It should also show the laboratory name, accreditation or qualification status where available, report number, issue date, sample receipt date, sample description, photographs or clear identification details, and the basis for the statement of conformity. Even a technically correct report is weak audit evidence if it cannot be clearly linked to the purchased part.
The table below shows the restricted substances buyers should expect under RoHS Directive 2011/65/EU as amended by (EU) 2015/863. Limits are by weight in each homogeneous material, not by total assembly weight.
| Substance | RoHS maximum concentration value | Where it may appear on an idler pulley | What to confirm |
|---|---|---|---|
| Lead (Pb) | 0.1% or 1,000 mg/kg | Alloy additives, plating residues, pigments, stabilisers, bearing-related materials | Exact homogeneous material tested and whether any exemption is claimed |
| Cadmium (Cd) | 0.01% or 100 mg/kg | Pigments, plated coatings, stabilisers, legacy surface treatments | Reporting limit must be below 100 mg/kg |
| Mercury (Hg) | 0.1% or 1,000 mg/kg | Rare in this part family but still part of the RoHS scope | “Not detected” must be supported by the method reporting limit |
| Hexavalent chromium (Cr VI) | 0.1% or 1,000 mg/kg | Chromate conversion coatings, passivation layers, anti-corrosion treatments | Confirm Cr(VI) was measured, not only total chromium |
| PBB | 0.1% or 1,000 mg/kg | Flame-retarded polymers, labels, sleeves, packaging materials | Polymer, label, or packaging material should be tested separately |
| PBDE | 0.1% or 1,000 mg/kg | Flame-retarded plastics, caps, labels, sleeves, packaging materials | Check sample preparation and brominated flame-retardant scope |
| DEHP | 0.1% or 1,000 mg/kg | Flexible PVC, soft caps, seals, labels, sleeves, bags, or packaging | Verify the tested material matches the production resin or compound |
| BBP, DBP, DIBP | 0.1% or 1,000 mg/kg each | Plasticised seals, caps, labels, sleeves, bags, or packaging | Ask for sample name, sample mass, extraction method, and separate results |
