A machined component can be dimensionally perfect, finish verified, and still fail at the border of the European Union. Substance restrictions attach to the materials and coatings inside your parts, not to the drawing. That is why buyers shipping into EU markets treat RoHS REACH machining declarations as part of the deliverable rather than a paperwork afterthought. RoHS limits specific hazardous substances in electrical and electronic equipment, while REACH governs chemicals across European commerce, including the alloys, plating chemistries, and coatings that touch every machined assembly. This guide explains what those rules ask of a CNC supplier and what evidence a buyer should require before a container moves.
What RoHS REACH Machining Compliance Actually Covers
RoHS, the EU restriction of hazardous substances directive, bars ten substances above threshold concentrations in electrical and electronic equipment placed on the EU market: lead, mercury, cadmium, hexavalent chromium, two flame-retardant families, and four phthalates. The limits apply to each homogeneous material, meaning every coating, plating layer, solder, and alloy counts on its own. REACH is broader. It registers and controls chemicals placed on the EU market, maintains a candidate list of substances of very high concern, and obliges communication about items above 0.1 percent by weight.
The two regimes overlap without replacing each other. A machined valve body for a hydraulic controller may sit under RoHS because of its electronic actuator and under REACH because of an SVHC in a seal or marking ink. Scope logic lives in the destination market rules and the end-item function, which is exactly why an early conversation with the machining partner matters.
Why Solid Metal Parts Still Fall in Scope
Machinists often assume solid metal is automatically clean. It is not. Lead is a deliberate addition to free-machining steels and brasses, improving chip breakage at the cost of RoHS exposure when the part enters electronic equipment. Specific exemptions cover some lead-in-alloy uses, but exemptions are limited, application-specific, and subject to expiry. Cadmium plate, hexavalent conversion coatings, and tin-lead solder finishes are squarely restricted in scope products. Sealants, inks, marking compounds, and paint can carry restricted phthalates.
Homogeneity is the concept buyers should internalize. The rules apply to the smallest unit that cannot be mechanically separated, so a plating layer, a conversion coating, and a base alloy are three separate homogeneous materials on one bracket. A serious RoHS REACH machining strategy therefore manages the whole stack of materials on the part, not just the alloy callout on the print.
Material Certificates and Declarations of Conformity
Evidence starts upstream. Every raw material lot should arrive with a certificate naming the alloy composition, including lead content where relevant. Distributors should pass through supplier declarations that trace the lot to a melt source. For imported stock, confirm that the foreign producer works to EU thresholds rather than a domestic standard that permits more. A mill certificate is only as strong as the chain of custody behind it, which is why traceability practice sits at the center of our CNC machining quality control overview.
On the REACH side, suppliers answer customer inquiries against the current candidate list and pass information down the supply chain. Ask vendors to state which candidate-list revision their declaration reflects. A document tied to an outdated list is a small audit finding waiting to become a large one during a customer questionnaire.
Plating, Coatings, and the Hidden Risk Layer
Finishing is where well-run programs fail most often. Zinc plating historically relied on hexavalent chromate conversion coatings for corrosion resistance; trivalent alternatives now cover most applications, but buyers and shops must verify which chemistry actually went into the bath. Cadmium plating persists in some legacy defense and aerospace specs and is restricted under RoHS. Tin-lead plating buries lead in a homogeneous layer. Anodizing is generally clean, but sealing salts and dyes can carry SVHCs. The machine shop’s job is to route parts only to approved processors and keep finishing chemistry documented on the traveler.
This is a specification problem before it becomes an execution problem. Engineers who design for compliance early, choosing trivalent conversion coatings, lead-free free-machining grades where electronics exposure applies, and declared marking inks, save everyone a retrofit. Our DFM guidelines for outsourced CNC projects covers the same principle from the design side: the cheapest compliance decision is the one made before print release.
How a Machine Shop Demonstrates Compliance
A credible RoHS REACH machining demonstration is a package, not a signature. It includes a declared bill of materials matching what was actually purchased, with certificates tied to lot numbers. It includes processor approvals for plating, heat treat, and painting, with chemistry declarations for each bath family. It includes incoming inspection that checks certificates against the recipe rather than filing them unread.
Strong shops add verification layers. X-ray fluorescence screening on selected parts and stock catches contamination that paperwork would miss, especially on imported fasteners and coating samples. Documentation control matters just as much, since the candidate list and exemption wording move over time and declarations must be refreshed when they do. Ask which annex and list revisions the supplier tracks and how fast updates reach live programs. That answer reveals whether compliance is a living system or a PDF downloaded once and forgotten.
Assembling a Checklist for EU-Bound Orders
Practically, a short checklist keeps a buyer out of gray zones. First, confirm whether the end item is electrical or electronic, since that is the RoHS trigger. Get a material declaration for every alloy in the part, with lead content stated. Verify the finishing specification: trivalent versus hexavalent conversion coating, cadmium-free, lead-free where required. Request a supplier declaration of conformity dated to the current SVHC candidate list. Ask whether the shop physically segregates compliant work or relies on paperwork alone. Then compare expectations with your sector, because medical device and food equipment buyers face different material rules than consumer electronics sourcing; our articles on medical CNC machining and food-grade CNC machining explain those separate regimes.
None of this is paranoia. EU market surveillance authorities do detain shipments over substance documentation, and a held container costs more than a month of paperwork. Treat declarations the way you treat inspection reports: as part of the shipment, verified before release.
Does RoHS apply to a bare machined metal part?
RoHS regulates finished electrical and electronic equipment, and the restriction flows down the supply chain through contracts and declarations rather than by direct legal duty on every component supplier. A machined housing with no electronics is not itself regulated, while the same housing inside a controller almost always is. The practical answer comes from your customer obligations, so collect the material and finishing declarations regardless of the classification debate.
What is the difference between RoHS and REACH?
RoHS restricts ten named substances in electrical and electronic equipment with strict concentration caps per homogeneous material. REACH covers the whole chemical supply chain in the EU, adding registration, restriction, and communication duties around a continuously updated candidate list. A part can satisfy one regime and fail the other, so a serious compliance file addresses both separately and names the revisions checked.
Do I need substance testing on every shipment?
Rarely. Declarations and certificates are the backbone, with targeted testing as verification: screening suspicious incoming stock, periodic checks on plating baths, and full analysis after any undocumented substitution. A clean declared bill of materials combined with selective screening gives buyers the strongest RoHS REACH machining package at sensible cost.
