Three Kinds of Sample, Three Different Purposes

"Send me a sample" is the vaguest sentence in overseas sourcing, and it produces a vague result. Chinese suppliers work with three distinct categories, and asking for the wrong one wastes your money or your schedule.

The existing sample. A unit of something the factory already makes, pulled off a shelf. Cost is typically the unit price plus shipping, sometimes free on higher-value inquiries, and it arrives in three to seven days by courier. Its purpose is to evaluate the factory's baseline workmanship and to check a component you plan to use as-is. It tells you nothing about your product.

The custom or counter sample. A unit built to your drawings, usually by hand or with soft tooling, sometimes with 3D printed or CNC parts standing in for molded ones. Cost runs from $150 for something simple to $3,000 or more for an assembled electromechanical device, and lead time is two to five weeks. This is the sample that tells you whether the factory understood your data package. Expect to pay a tooling or engineering fee and expect to iterate at least twice.

The pre-production or golden sample. A unit built with production tooling, production materials, and the actual assembly process, in final packaging. This is the one you approve in writing and against which the whole order is judged. Its cost is bundled into the tooling investment and its lead time follows the mold schedule.

Order them in that sequence. Founders who jump straight from a CAD file to a production order skip the two steps where mistakes are cheap. If you are still at the concept stage, a prototype from a rapid-prototyping shop is faster and more controllable than a factory sample, as covered in getting a prototype made in China.

Writing a Request That Produces a Usable Result

A bad sample is nearly always caused by a bad request. Factories build exactly what the documents say and fill every gap with whatever is cheapest and closest to hand. A request that works includes:

  • 2D drawings with tolerances, not just a STEP file. The 3D model shows geometry; the drawing states which dimensions are critical, what the tolerance is, and what the surface requirements are.
  • Material by full designation. "ABS" is not a material. "ABS, PA-757 or equivalent, natural, UL 94 HB" is.
  • Color and finish references. Pantone numbers, texture standards, gloss level. Send a physical reference chip if color matters.
  • The approved vendor list for any component you will not accept a substitute on, particularly semiconductors, connectors, and batteries.
  • A functional test description. What the sample must do, measured how, with what acceptance limits.
  • The quantity. Always order at least two or three identical samples. One for you, one to keep sealed as a reference, one for a test that might destroy it.
  • A stated deadline and a photo checkpoint partway through, so a misunderstanding surfaces before the sample ships.

Ask for a sample confirmation sheet before they build: their restatement of the specification, with any substitutions they intend to make, for your written approval. That single document catches most divergences, and everything here belongs in the wider manufacturing data package.

One more thing worth verifying before you send drawings: whether the company you are talking to actually builds anything. A trading company will forward your files to a factory you have never vetted, add margin, and become a lossy communication layer. The tests are in factory vs trading company.

Protecting Your Design at the Sample Stage

The sample stage is when your full design leaves your control, usually before any real commercial relationship exists. A standard US-style NDA is close to worthless here because it is difficult and slow to enforce against a Chinese entity. The instrument that works is an NNN agreement, written in Chinese, governed by Chinese law, with jurisdiction in the supplier's local court and specific contractual damages stated as a number. It covers non-disclosure, non-use, and non-circumvention, and the reasoning is set out in NNN agreements for China manufacturing.

Three practical measures go alongside it. Split the work where the design is genuinely novel, so one supplier makes the enclosure, another the board, and nobody holds the whole product. File before you send, because a design patent or provisional application submitted prior to disclosure preserves options you cannot recover later, and register your trademark in China in your own name early, since registration there is first-to-file. And hold back what the sample does not need: firmware, calibration data, and test procedures can often stay with you until the relationship is proven. The realistic risk picture is in will a Chinese factory copy my product.

What to Check When the Box Arrives

Photograph the sample as received, in the packaging it came in, before you touch anything. Then work through a written checklist rather than a general impression. Measure the critical dimensions with calipers against your drawing and record the numbers in a table. Do not eyeball fit. Check material by more than appearance: weight against the calculated mass, a burn or solvent test where appropriate, and a request for the material certificate. On electronics, open the unit and verify the actual components installed against your bill of materials, part number by part number, because unauthorized substitution is the most common quiet deviation and it is also how counterfeit parts enter a supply chain, a problem detailed in counterfeit electronic components.

Run the functional test you specified on all the samples, not just the best-looking one, then test the third unit to destruction: drop it, cycle the mechanism, pull the cable, run it hot. Write your findings as a numbered deviation list, each item with the drawing reference, the measured result, and the required correction. Send that list, not a paragraph of impressions. When the corrected sample arrives, formalize the acceptance as a first article inspection with dimensional results in writing, and seal one approved unit in your own office as the retained reference for the life of the product.

Hidden Costs and Schedule Reality

The sample invoice is not the cost of sampling. Add courier charges of $60 to $200 per shipment, which for a three-round iteration is real money. Add import duty and customs handling on each inbound package. Add the tooling or fixture fee for a custom sample, often $300 to $2,000, and confirm in writing whether it is credited against a future order and who owns the tooling, a question that gets serious once real molds exist and is unpacked in who owns your injection mold in China.

On schedule, assume three iteration rounds rather than one. Each round is two to five weeks of build plus a week of shipping plus your own evaluation time, which puts a realistic sampling phase at ten to eighteen weeks. Compress it by paying for expedited builds and by making the first request unambiguous, not by skipping rounds, and check the calendar against the annual lunar new year shutdown.

Get the Sample Right the First Time

Projects House prepares the drawings, tolerances, and test criteria that make a factory sample worth the wait, and reviews what comes back against them. Send us your design status through our contact form.