This article is part of the CNC Tolerances & Quality Control Guide: GD&T, CMM, Cpk, PPAP on CNX Precision.
Selling machined components into Europe means answering substance questions long before the first purchase order. RoHS REACH compliance machining covers the base metal, any processing residues, and every finish applied to a part. CNX Precision treats both regulations as a documentation discipline as much as a manufacturing one. Restricted substances are controlled at the source, verified with material certificates, and checked again after surface treatment. For exporters, that file is as important as the dimensional report that ships with the parts.
Which Substances RoHS and REACH Restrict
RoHS and REACH restrict different sets of substances and work through different legal mechanisms. RoHS applies to electrical and electronic equipment and limits ten substances, including lead, mercury, cadmium, hexavalent chromium, and selected brominated flame retardants and phthalates. Most carry a maximum concentration of 0.1 percent by weight in homogeneous materials, while cadmium is limited to 0.01 percent. Certain applications carry exemptions, such as lead in free-machining copper alloys, and those exemptions shape material selection.
REACH is broader. It governs chemical substances and applies to almost any article placed on the EU market. Its most visible obligation for machined part buyers is the candidate list of substances of very high concern, known as SVHCs. When an article contains an SVHC above 0.1 percent by weight, suppliers must pass information down the supply chain. The list grows over time, so a part that was clean last year can attract a new reporting duty without any design change.
Material Certificates and Traceability
Compliance starts with the raw material. Mill certificates, also called material test reports, identify the alloy and its composition. CNX Precision requests material declarations from metal suppliers and keeps certificates linked to each production lot. When a buyer asks which heat of aluminum went into a batch, that traceability makes the answer immediate.
Certificates alone are not the whole story. The material must match the certificate, so incoming inspection checks alloy marking and lot numbers against the paperwork. If a supplier swaps stock or buys from a secondary source, the certificate chain must follow. For critical programs, buyers can request screening analysis such as XRF testing to confirm the declared composition.
Material choice also interacts with exemptions. Free-machining brass and some copper alloys rely on lead for chip breaking, and RoHS exemption categories permit that lead within defined alloy families. When a design calls for such an alloy, the compliance file should cite the relevant exemption so auditors can verify the scope.
Finishes and Plating: Where Risk Hides
Surface treatment is the step where compliance most often breaks. A bare machined part may be clean, while the plating, passivation, or coating applied afterward introduces restricted chemistry. Hexavalent chromium passivation on zinc plating is the classic example, now widely replaced by trivalent alternatives. Certain pigments, conversion coatings, and sealants can also carry restricted metals or organic compounds. Anodizing is generally lower risk because the process grows from the base metal itself, though dyes and sealing baths still deserve a declaration.
The practical control is to specify compliant finishes on the drawing and verify them with the finish supplier’s own documentation. Ask whether the plating line uses hexavalent chromium, whether coatings carry their own declarations, and whether the finish shop segregates compliant and non-compliant processes. When CNX Precision manages finishing through partners, it collects finish-house certificates the same way it collects mill certificates, so the compliance file covers the part exactly as shipped.
How Suppliers Prove RoHS REACH Compliance Machining
Demonstrating compliance is mostly a documentation and in-process control exercise. A credible supplier assembles a file for each part or program: mill certificates, finish declarations, supplier self-declarations, and, where risk is high, test reports from qualified laboratories. XRF screening can verify incoming material quickly, and targeted chemical testing can confirm finishes when drawings demand it. Some buyers also require periodic third-party testing for high-volume parts, which adds another layer of assurance.
In-process controls keep the file honest. Shops document which materials are approved, how stock is segregated, and how they prevent mixing compliant and non-compliant lots on the floor. Change control matters too: if a finish supplier changes chemistry, the declaration must be refreshed. Buyers evaluating a supplier should ask to see a complete compliance file for a live part, not a generic policy statement. The speed and completeness of that response says a great deal about how the shop manages RoHS REACH compliance machining.
What Buyers Should Request Before Ordering
The EU market treats substance compliance as a condition of sale. Importers bear legal responsibility for the products they place on the market, so European customers flow RoHS and REACH requirements down through contracts, quality agreements, and audits. A machining supplier that cannot answer substance questions quickly becomes a supply chain risk, even if its prices and lead times look attractive.
For EU-bound programs, RoHS REACH compliance machining should be built into the quotation stage. Ask for mill certificates tied to lot numbers, finish supplier declarations, a conformity statement covering the part as shipped, and a defined process for refreshing documents when the SVHC candidate list changes. Agree on traceability depth too, so a compliance question about one shipment can be answered from records rather than memory.
CNX Precision prepares these documents as a standard part of RoHS REACH compliance machining for export programs and updates declarations when regulations change. If your parts enter the EU market, request the compliance file alongside the quote and judge the supplier by the answer.
Frequently Asked Questions
Do bare machined parts fall under RoHS?
RoHS directly regulates electrical and electronic equipment, so a bare machined part is not in scope by itself. Once the part is installed in an electronic product sold in the EU, however, the finished product must comply, and buyers pass that requirement to component suppliers through purchase contracts. Most CNC suppliers therefore treat RoHS as a standard expectation for electronics parts.
What documents prove RoHS REACH compliance machining?
Expect three layers: mill certificates or material declarations for the base metal, declarations for any surface finish, and a supplier conformity statement covering the part as shipped. Screening reports such as XRF results strengthen the file. Documents should name the part or material, carry dates, and trace back to the production lot.
Can a finish make an otherwise compliant part non-compliant?
Yes. Plating, passivation, and coatings are the most common sources of restricted substances on machined parts. Hexavalent chromium passivation on zinc plating is the well-known case. Always specify the finish chemistry, collect the finish supplier’s declaration, and confirm that the finish house segregates compliant processes from non-compliant ones.