How to choose an industrial subcontractor: 10 criteria

Handing manufacturing over to a third party means entrusting it with part of the quality, lead times and sometimes the intellectual property of your product. An attractive price does not make up for a rejected batch, a three-week delay or a workshop that disappears mid-series. Choosing on a single dimension, most often price, is the most common mistake.

Here are the ten criteria to examine, detailed in the following sections:

1. Skills and machine fleet
2. Capacity and workload
3. Quality system and certifications
4. Proximity
5. Responsiveness
6. References
7. Financial health
8. Communication
9. Price
10. Contract terms

Before applying them, prepare a clear brief: a precise manufacturing specification lets every candidate respond on the same basis, and therefore lets you compare them properly.

1. Skills and machine fleet

Check that the workshop masters your process, your material and your requirements: type of machines (3 or 5 axes, turn-mill, laser cutting), maximum machinable dimensions, inspection equipment available and complementary operations carried out in-house. Ask for examples of parts comparable to yours and, if the stakes justify it, visit the workshop. Browse the areas of expertise to identify the right trade.

Three questions quickly reveal a workshop’s level: what is the largest part you can machine or cut? What tolerances do you usually hold, and how do you inspect them? What share of the manufacturing do you do in-house? Precise, quantified, verifiable answers are a good sign; vague answers, or ones that are always positive, deserve a closer look.

2. Capacity and workload

A good workshop may be too busy for you. Ask about its usual lead time, its ability to keep up a delivery rhythm on a series, its backup machines in case of breakdown and the operations it subcontracts itself (treatments, inspection). A long subcontracting chain lengthens lead times and dilutes responsibility: know who does what.

Certifications attest that a management system is in place and audited by an independent body. The most common in industrial subcontracting:

• ISO 9001: quality management, all sectors. It is the most widespread foundation.
• EN 9100: quality standard for the aerospace, space and defence sectors.
• IATF 16949: automotive industry standard, built on ISO 9001.
• ISO 13485: quality management for medical devices.

Ask for the certificate and check its scope (sites and activities covered), its expiry date and the certification body. For special processes in aerospace (heat or surface treatments, non-destructive testing, welding), specific accreditations such as Nadcap may be required by your own customers. A metrology laboratory may, for its part, be accredited to ISO/IEC 17025. Beyond the paperwork, ask about actual practice: first-article inspection, material traceability, handling of non-conformities.

4. Proximity

A nearby workshop makes visits, prototype adjustments and fast deliveries easier, and reduces transport. It is not an absolute criterion: for a stable series, a more distant supplier can be very competitive. The regional pages help you identify industrial areas.

5. Responsiveness

The time taken to reply to a quote request gives a first impression of how the workshop operates. The quality of the questions it asks says even more: a workshop that has read your drawing flags ambiguities before quoting; one that replies without any question may not have looked at everything. Also check that the quote states its validity period and the starting point of the delivery lead time (from order, from receipt of the files, from approval of the first sample).

6. References

Ask for comparable work (parts, materials, sectors) and, with the company’s agreement, a customer contact. Samples or a small first order let you test before committing to a series.

7. Financial health

A fragile workshop can interrupt a series in progress, especially if you have paid a deposit or financed tooling. A few simple checks, for French companies:

• SIRET (the French company establishment number): a 14-digit number (a 9-digit SIREN plus 5 digits for the establishment). Check that it matches the company named and that it is active in the Insee Sirene register (the French national statistics institute’s business register).
• Annual accounts: turnover, profit and equity can be consulted in the official registers (the commercial court registry, the national business register) where the company has filed them and has not requested confidentiality. Otherwise, ask for alternative evidence.
• Insolvency proceedings: search for the company in the Bodacc (the French official bulletin of civil and commercial announcements).
• Dependence and track record: a workshop that earns most of its turnover from a single customer is more exposed.

On Meaflow, the “Verified company” badge indicates that a supplier’s SIRET has been verified. It attests to the company’s administrative existence, not the quality of its work: the other criteria still need to be examined.

8. Communication

An identified contact, clear progress reports and anticipation of delays are worth as much as a good machine fleet. The platform’s messaging system keeps a history of exchanges, which is useful in the event of a dispute. Also observe how the workshop handles bad news: a reliable partner warns you of a delay or a doubt about a drawing before the deadline, with a solution to propose.

9. Price

Price matters, but compare full costs: price per part, launch costs, transport, risk of scrap or delay. An abnormally low offer deserves an explanation. Ask for the breakdown of cost items; the guide CNC machining prices helps you read them.

10. Contract terms

Formalise the order: drawing reference and index, quantities, price, lead time, inspection requirements, acceptance conditions and handling of non-conformities. Specify who owns the tooling and the drawings, and sign a non-disclosure agreement if needed (see drawing confidentiality and NDAs). Finally, check the payment terms: in France, payment periods between businesses are regulated by the Commercial Code, and the general ceiling is 60 days from the invoice issue date.

For a recurring need, a framework contract or open order can set prices by quantity break, the validity period of the rates and the delivery rhythm. This secures your supply, and the workshop can plan its workload.

When the stakes are high, reduce the risk by proceeding in stages rather than handing over a large series straight away.

• Pilot order. A small representative quantity lets you assess the real quality, adherence to lead times and the quality of the relationship, at limited cost.
• First-article inspection. Have the critical dimensions validated on the first part before launching the rest of the batch, and keep the report as a reference for later orders.
• Organised goods-in inspection. Define in advance how you will inspect the parts received and the time limit for reporting a non-conformity.
• Second supplier. For a critical part, qualifying a second workshop avoids depending on a single supplier if something goes wrong.

Score each candidate from 1 to 5 on each criterion, multiply by the weight, then add up. The weightings below are an example to adapt to your project. Deal first with the knock-out criteria (dimensional capacity, certification required by your customer).

On Meaflow, posting a request is free: several suppliers can send you their quote, which you compare, then you discuss through the messaging system with those who interest you. Your drawings are only visible to logged-in members. You can also browse the supplier directory before publishing. To move from a first test to regular production, read from prototype to series production.