---
id: KB-IU-019
url: https://app.codecontract.io/help/manufacturing/who-assembles-the-machine-and-puts-their-name-on-it
idioma: en
categoria: sector-industria
subcategoria: maquinaria
audiencia: usuario
nivel: avanzado
actualizado: 2026-08-13
tambienEn: [es]
relacionados: [KB-IU-004, KB-NO-024, KB-IU-016]
citadoPor: [KB-IU-020]
---

# Who assembles the machine and puts their name on it

_You buy components from twelve suppliers and sell a machine. Twelve sets of papers do not add up to yours._

**Responde a:** machinery manufacturer technical file · i assemble machines from third party components · declaration of conformity for an assembly · who is liable for an assembled machine

Every component arrives with its documentation in order. The assembly is built, tested, delivered, and the client signs happily. Months later comes the question that throws everyone: they are not asking for the components' papers, **they are asking for the assembly's** — which never existed in any box.

## The sum that does not add up

| What you hold | What they ask for |
| --- | --- |
| Twelve documents for twelve components | One document for the assembly |
| Each compliant separately | That the assembly is, running together |
| Each maker's manual | A manual for your machine |
| Nothing about how they interact | **Precisely that, and only you know it** |

> [!IMPORTANT]
> **By assembling, you become the manufacturer of something new.** It is the step most often overlooked, and it is no formality: the risks of an assembled machine are not the sum of its parts' risks — they appear in the interaction, in combined movements, in what happens when one component fails and the rest keeps running. Nobody but you can document that, because nobody else has seen the whole assembly.

## What to build besides the machine

1. **The assembly's file, not the component folder** — With a risk assessment of the assembly in operation.
2. **Each component's documentation, inside it** — Stored, not linked to the supplier's website.
3. **A manual for your machine** — Twelve supplier manuals are not the machine's manual.
4. **And which version of each component each serial number carries** — It is what lets you answer when a supplier changes.

> [!WARNING]
> The point always discovered late: **the component swapped for an equivalent on one specific unit**. A supplier stops delivering, a similar one goes into the three machines built that month, and nobody records it anywhere. From then on the file describes a machine that is not the one the client has — and when that client asks for a part, an adjustment or a service, the information you give will be another machine's.

> [!NOTE]
> What duties an assembler assumes, when the result counts as a new machine and what documentation must be issued and kept is set by the applicable product rules. **Your adviser or notified body settles that before the first delivery**; here we explain why a component folder is not the assembly's file.

**Are the components' papers enough?**

They are part of the file. The assembly needs its own.

**What if I only integrate without modifying?**

It depends on the case, and it is exactly the question for your adviser.

**How long do I keep the file?**

Counted from the last unit sold, not from the design.

## Ejemplos

**You are asked for the assembly's file and all that exists is a folder of component papers.**

- Builds the assembly's file with a risk assessment of it in operation

→ The document describing the machine you sell exists, not just its parts.

**A component is swapped for an equivalent on three units and nothing is recorded.**

- Records which version of each component each serial number carries

→ The file describes the machine each client actually has.

**The manual handed over is a folder containing the twelve supplier manuals.**

- Writes the manual for your machine, covering what the assembly does

→ The client knows how to use the machine, not twelve loose components.

**A component's documentation was linked to the supplier's website, which was redesigned.**

- Keeps a copy of every document inside the file

→ The file survives other people's website changes.

**A client asks for a spare part and is given one from another version.**

- Checks what that serial number carried before answering

→ The spare fits first time and does not generate a second visit.

**The last unit is sold and the file is archived as closed.**

- Keeps the file counting from the last unit sold

→ The file still exists when the question arrives, years later.