Protecting your drawings in subcontracting: NDAs, ownership and good practice

Entrusting a drawing to a workshop means handing over more than a picture: dimensions, tolerances, material choices, sometimes the architecture of a whole product, and often your target price. Protection rests on three complementary layers:

• the contract: confidentiality agreement, accepted quote, purchase terms;
• the law: trade secrets, intellectual property;
• practices: what you share, when, through which channel and with whom.

Match the effort to the risk. A simple bracket does not justify a heavy protocol; a novel mechanism does. And a well-drafted agreement does not protect a drawing sent indiscriminately to ten contacts.

A confidentiality agreement (NDA, for non-disclosure agreement) commits a party to keep the information it receives secret and to use it only for a defined purpose. It may be one-way (only the workshop is bound) or mutual (if the workshop also shares its know-how). The usual clauses:

• Parties and purpose: who is bound, and for which project (studying, quoting, manufacturing).
• Confidential information: drawings, CAD models, specifications, processes, prices, exchanges, on any medium.
• Exclusions: information already public, already lawfully known to the recipient, legitimately received from a third party or independently developed.
• Obligations: use limited to the project, access restricted to those who need it, reasonable security measures, no unnecessary copying, no passing on to another subcontractor without written agreement, and, if you wish, a ban on reverse engineering of the parts.
• Duration: the period of the exchanges, plus a confidentiality period that outlasts it, to be adapted to the sensitivity of the information.
• Return or destruction of documents and digital files at the end of the project.
• Penalties and disputes: liability, any penalty clause, governing law, competent courts.

An NDA should remain readable and proportionate: a workshop will hesitate to sign an excessive text. Also check that it does not contradict your general terms of purchase or the accepted quote.

French Law No. 2018-670 of 30 July 2018 on the protection of trade secrets (“secret des affaires”), which transposes Directive (EU) 2016/943, created a protection regime in the French Commercial Code (articles L. 151-1 et seq.). Information is protected as a trade secret when it meets three conditions:

1. it is not, as such or in the precise configuration and assembly of its components, generally known or readily accessible to persons familiar with this type of information because of their sector of activity;
2. it has commercial value, actual or potential, because it is secret;
3. it is subject, by its lawful holder, to reasonable protection measures, given the circumstances, to keep it secret.

The third condition is the most practical for you: without reasonable measures, it becomes difficult to invoke the secret. An NDA, a “Confidential” marking, restricted access and a distribution log are such measures. In the event of unlawful acquisition, use or disclosure, the Commercial Code provides for civil actions: measures to prevent or stop the infringement, and compensation for the harm.

Keep two limits in mind. This regime replaces neither a patent, nor design protection, nor copyright: if you are considering a patent, file before any uncontrolled disclosure. Second, studying or dismantling a product made available to the public or lawfully held is in principle permitted, unless the contract says otherwise: hence the value of a reverse engineering clause.

An NDA protects information; it does not say who owns the results of the project. Without anything in writing, areas of uncertainty remain. Clarify, in the accepted quote, the order or a framework contract:

• Your drawings and files: they stay yours, the workshop having only a right of use to carry out the order.
• Documents created for the project: machining programs, jigs, manufacturing drawings, modifications proposed by the workshop. Who owns them? Who may reuse them?
• The workshop’s know-how: processes, settings, standard tools. It remains in principle theirs.
• Tooling: moulds, cutting tools, jigs that you finance. Ownership, storage, maintenance, insurance, a ban on using them for a third party, return at the end of the run or on a change of supplier.
• Parts: prototypes, scrap, leftover parts. Can they be sold? It often needs to be prohibited when they bear your brand.
• Improvements: who gets the ideas that arise from the collaboration?

On tooling, see also our guide from prototype to series production.

The French law No. 75-1334 of 31 December 1975 on subcontracting is often cited as a general protection for workshops or drawings. Its scope is more specific; here is a simplified overview. It applies in France.

What it defines

In essence, it defines subcontracting as the operation by which a contractor entrusts, by a subcontract and under their own responsibility, to another person called the subcontractor, the performance of all or part of the works contract or of part of the public contract concluded with the project owner.

What it provides

It primarily protects the subcontractor in the area of payment. The main contractor must in particular have each subcontractor, and their payment terms, accepted by the project owner. The subcontractor has a direct action against the project owner when the main contractor does not pay them one month after formal notice (article 12). The text also provides, depending on the case, for payment guarantees.

What it does not do

• It does not deal with confidentiality or with ownership of drawings or tooling: these points are settled by contract.
• It does not automatically apply to every order of parts. Its framework is the chain “project owner, main contractor, subcontractor”. A company that has parts made for its own products falls rather under ordinary contract law (works contract or sale). The classification depends on the facts and may be argued before the courts.
• It does not replace the terms of the order: price, lead times, quality and liability still have to be written down.

So do not count on this text to protect your drawings. If in doubt about whether it applies to your situation, seek legal advice.

• Share the minimum. To quote a part, its drawing is enough: not the full assembly or the product’s bill of materials. Hide whatever is not needed for the quote.
• Proceed in stages. A simplified drawing for the quote; full drawings and native files only after the NDA is signed, and ideally after the supplier has been chosen.
• Watermark and mark. A statement such as “Confidential, property of [your company], reproduction prohibited” in the title block, and a watermark in the recipient’s name, help trace the source of a leak.
• Control versions. Revision indices, a distribution log (who received what, when), metadata removed from files.
• Choose the right format. PDF or STEP rather than an editable native file, unless there is a real need (see CAD file formats).
• Segment. For a sensitive product, split the components between several suppliers.
• Close out cleanly. At the end of the project, ask for the files to be returned or destroyed, with written confirmation, subject to legal retention obligations.

On Meaflow, the drawings and documents attached to a request are visible only to logged-in members: they have no public address. When you post a request, you can indicate that a confidentiality agreement is required; the note appears on the request and alerts suppliers. Three points to note:

• The note is informative. Meaflow is not a party to the agreement, does not draft it and does not keep it: conclude it directly with the supplier before exchanging sensitive information.
• “Logged-in members” means all registered members, not only the supplier you will select. For highly sensitive parts, attach a simplified drawing and keep full drawings for exchange by messaging, after signature.
• The description, photos and public questions are visible to everyone: put nothing confidential in them.