How an OEM Qualifies a New Metal Supplier: What a Fabricator Trial Package Contains

Why a serious buyer sends a trial package instead of an RFQ

When a buyer already knows what they want and is only deciding who makes it, they do not send a request for quotation. They send a trial. The trial is a small, closed, low-risk piece of work with formal instructions, and it is designed to answer one question: can this supplier actually make our parts to the standard we require.

If you have never received one, it is worth understanding what is inside and what it is really testing, because the way you respond matters more than the price you quote.

What a trial package contains

The structure is consistent across industries, even when the part is completely different.

• A drawing package — PDF drawings plus the native CAD, and often a neutral format as a fallback. STEP files matter because they carry the solid model rather than a view of it.
• Instructions — what to quote, what to include in the price, what the trial is for, and how the result will be judged. This is the document that removes ambiguity, and it is the one you should read twice.
• A bill of materials or a parts list, so the supplier prices the same scope.
• Checksums or a file manifest — SHA256 or similar, so buyer and supplier are working from provably identical files. If a supplier’s copy differs from the buyer’s, the trial is void.
• Quality requirements — dimensional tolerances, surface specification, the finish, what constitutes a reject.
• Logistics instructions — ship-to address, packing expectation, who pays freight, and any labelling required.
• The commercial terms — who pays for the trial, whether it is credited against a first production order, and the deadline.

When a buyer sends something like this, they have usually already shortlisted suppliers. They are not asking whether the job is possible. They are asking whether you will hit a date and a standard on a part nobody is watching.

What the trial is really measuring

Price is almost never the deciding factor on a trial. Buyers who intend to place real volume are checking five things, usually without saying so explicitly.

1. Communication responsiveness

Did you acknowledge it, did you ask the right clarifying questions, did you confirm the deadline, and did you come back on the date you said you would? The trial is a proxy for how you will behave on a programme that matters.

2. Drawing comprehension

A good supplier reads the drawing and comes back with two or three questions that show they understood the tolerances, the assembly intent and the finish. A supplier who quotes straight from a PDF without questions has usually not read it.

3. First-article quality

The trial part is measured. Fits, flatness, hole positions, weld appearance, coating quality and whether it meets the finish spec. This is where a supplier that has been guessing rather than manufacturing shows up.

4. Document discipline

Do you return the completed trial package — the annotated drawing, the measurement report, the material certificate — when asked? A supplier who ships a good part and no paperwork fails the trial on process grounds.

5. Adherence to the deadline

Almost always. Trial parts are small and the queue is short, so a missed date is usually a capacity or planning problem, and the buyer is right to assume it will repeat at volume.

How to respond to a trial package

This is a short job, but it is a process job. The sequence below is what a strong response looks like.

1. Acknowledge within one working day. Confirm you have the full package, list what you received, and confirm the file integrity check.
2. Quote a date for the technical response, not the price. Two or three working days to read and question the package is normal and professional. Quoting a price before you have understood the part is worse than quoting late.
3. Come back with questions. At minimum: the material and thickness, the finish, the tolerances you are being asked to hold, whether the part is delivered assembled or as a weldment, and whether you are expected to supply purchased items such as castors or fasteners. Confirm explicitly whether the trial cost is creditable against the first order.
4. Send the quotation with the assumptions written down. Price, price breaks, tooling or NRE if any, freight terms, validity period, and what is explicitly excluded. An assumption written down is a dispute avoided.
5. Confirm the return package before you build. Ask exactly what documentation they want back with the part. Do not assume.
6. Build the first article, measure it yourself, and attach the report. Do not wait to be told to check. Self-verification is the cheapest way to demonstrate that you understand the tolerance.
7. Return the paperwork. Marked-up drawing, measurement report, material certificate, and a note of anything you would change for production.

One rule matters more than the rest: if you cannot hold a tolerance, say so in the quotation instead of hoping nobody measures it. A supplier who flags a tolerance as risky before the trial is trusted with the production order. A supplier who is caught out afterwards is not.

Questions worth asking in the trial phase

• Is the trial cost credited against the first production order, and at what point in the relationship?
• What is the acceptance criteria — a measurement report, a functional test, or both?
• Do you want a first article approved, or a production-intent part?
• What is the expected production volume and repeat cadence after the trial, per part?
• Is the trial part identical to the production part, or a simplified version of it?
• Do you want your own material certification format, and do you need a specific certificate title?

Common reasons a supplier fails a trial without knowing they failed

• Quoting from the PDF only. The 3D file and the manufacturing intent differ. Parts get made that assemble incorrectly.
• Not asking about finish masking. Masked areas produce a visible difference against the buyer’s reference sample.
• Sending a part with no measurement report. The part may be fine; the trial is still failed on process.
• Missing the paperwork deadline. The part arrived and the buyer could not release it for measurement.
• Not flagging the tolerance. One part outside tolerance, discovered by the buyer, is much worse than a documented limitation.
• Over-committing on date. Agreeing a date you are not certain of, in order not to lose the trial, is how a supplier ends up unable to run production later.

What we do

We take trial packages seriously. That means reading the instructions before the drawings, asking the questions that affect the price, confirming the acceptance criteria in writing, self-measuring the first article before shipping, and returning a complete documentation package with the part. If a part is at the limit of our process, we say so in the quotation and offer the design change that would bring it inside.

Our payment terms are T/T with payment before production, so for trial work the usual arrangement is payment against the order before we start. We are not able to open L/C terms, and we would rather tell you that at the quotation stage than after you have waited.

Received a trial package, or have one coming? Send the full package and we will come back within two working days with the questions that affect the price, and a quotation with the assumptions written down. Our first article and sample approval guide covers the process in more detail, and NDA and drawing protection covers what happens to your files.

Related pages: Quality control and inspection and inspection documents compared.