EU Machinery Regulation substantial modification workflow

Open the file with a change record that shows the product model, serial or configuration range, market status, and whether the change is physical, digital, or both. The definition applies after machinery or a related product has been placed on the market or put into service, so the record should distinguish a post-market or in-service change from ordinary design work before first release.

Describe who will carry out the change, whether the original manufacturer foresaw or planned it, and whether the change affects the whole machine, a related product, or only a part of an assembly of machinery. That scope matters because Article 18 ties the modifier's manufacturer obligations to the machinery or related product affected by the substantial modification, as demonstrated in the risk assessment.

Apply the substantial modification definition as a threshold test. A change should be treated as substantial only when the change was not foreseen or planned by the manufacturer, affects safety by creating a new hazard or increasing an existing risk, and requires one of the protective responses named in the Regulation.

Do not treat every service activity as substantial. The Regulation's recitals distinguish repair and maintenance operations that do not affect compliance with the relevant essential health and safety requirements from substantial modifications. A change that was foreseen or planned by the manufacturer also fails the Article 3(16) definition, but the manufacturer must still keep series production, risk evidence, instructions, and the declaration aligned where the planned change affects conformity.

Article 18 contains a narrow actor exception. A non-professional user who carries out a substantial modification to his or her machinery or related product for personal use is not considered a manufacturer under Regulation (EU) 2023/1230 and does not take the Article 10 manufacturer obligations through Article 18.

Do not extend this exception to a company, employer, professional user, service provider, integrator, or person modifying machinery for another user or for market supply. The exception also does not decide duties under workplace-safety, product-liability, electrical-safety, or other applicable Union or national law.

When the threshold is met, Article 18 treats the natural or legal person carrying out the substantial modification as the manufacturer for the machinery or related product concerned. If only part of an assembly is affected, the scope can be limited to the affected machinery or related product, but the risk assessment must demonstrate that boundary.

The modifier should then stop treating the activity as a maintenance closeout and run the manufacturer-obligation workstream for the affected scope. That includes ensuring conformity with applicable requirements, applying the relevant conformity assessment procedure, and declaring conformity on its own responsibility.

For a substantial modification, the evidence file should be rebuilt around the modified scope. Article 10 requires the manufacturer to ensure design and construction against Annex III EHSRs, draw up technical documentation, carry out or have carried out the relevant conformity assessment, then draw up the EU declaration of conformity and affix the CE marking after conformity has been demonstrated.

Select the conformity assessment route under Article 25 for the affected machinery or related product. Annex I Part A categories require the specified procedures involving a notified body route; Annex I Part B allows internal production control only when the machinery or related product was designed and constructed according to harmonised standards or common specifications specific to the category covering all relevant EHSRs; products not listed in Annex I use internal production control.

Close the workflow only when the file explains both the decision and the release state. The evidence should let a reviewer see why the change was or was not substantial, what hazards or risks changed, which product boundary was affected, and which conformity work was completed before the modified machinery or related product was placed on the market or put into service.

For substantial modifications, keep the updated technical documentation and EU declaration of conformity available for market-surveillance authorities for the required retention period. Keep unaffected-assembly evidence too, because the Regulation allows avoiding repeated tests and new documentation for machinery or related products in an assembly that are not affected by the modification.