Send Your Own Substrate: Using Test Prints and Demo Video Before the Balance Payment

The standard payment structure on Chinese printing machinery is T/T with a 30% deposit and the 70% balance falling due before shipment. Read that second clause slowly. The balance is not due on arrival, not on installation, and not on acceptance — it is due while the machine is still standing on a factory floor 9,000 km away. Once the wire clears, your remaining influence is a service relationship and a warranty document. Before it clears, you hold 70% of the contract value, and that is the window in which a UV printer sample print on your own substrate is worth arranging.

Most buyers of capital equipment know to ask for a test print. Far fewer specify it in a way that proves anything. A pretty photograph of a colour chart on the factory's own acrylic offcut, printed at the slowest quality setting on a demonstration machine, tells you the supplier owns a working printer. It does not tell you that the machine crated with your serial number will hold ink on the anodised aluminium your customer keeps reordering.

Where the test print sits in the money sequence

Map the milestones before you negotiate them, because the useful question is not "will you do a test print" but "which payment does the test print gate".

The row in bold is the one that matters, and it only matters if the sequence is written that way. Ask for the test print to be scheduled and reported before the balance invoice is issued, not after. Suppliers on this payment structure will often agree, because the run-off is a step many already perform — Longrun's published process, for example, lists a test print of the buyer's files and substrates as step three of five, ahead of crating and shipping. The negotiation is about timing and evidence, not about whether the machine gets switched on.

If you want a retention against commissioning as well, that is a separate conversation about milestone structure, and it belongs in the contract at order stage rather than in an email six weeks later. The wider mechanics of splitting equipment payments across milestones are covered in the guide to paying for industrial equipment from China with T/T, L/C and milestone terms.

Why it has to be your material, not theirs

UV ink adhesion is a property of the interface, not of the printer. The same machine, the same ink and the same cure setting will produce a sample that passes a fingernail test on one sheet of PVC and fails on another, because the two sheets came from different extruders with different surface energy, different mould-release residue and different plasticiser migration. A supplier's demonstration acrylic is a best case by selection — it is the material that has been printing well in their showroom for months.

Send the material you actually buy. Three practical rules:

• Send the lot, not the type. "3 mm foamed PVC" is not a specification for an adhesion test. Send offcuts from the batch you are running now, and write the supplier's name and lot number on the back of each piece in permanent marker.
• Cut every coupon in half and keep one half. Send one half, retain the other. When the printed sample comes back you can compare printed against unprinted from the same sheet, and you have proof of what you supplied if the result is disputed. This costs nothing and settles most arguments about "that is not the material you sent".
• Include your worst case, not your showcase. Anodised aluminium, powder-coated steel, silicone-release-coated board, corona-treated film that has been in stock for four months, glass. If the machine handles the awkward third of your work you already know it handles the easy two thirds.

Two logistics points people miss. Buyer-supplied material entering China is an import in its own right, with a declaration, a value and potentially duty — agree in writing who arranges and pays for that leg, and whether the samples are consumed or returned. And send enough. A single A4 coupon gives you one attempt; a run-off that needs a re-cure at a different lamp setting has just used your entire material budget. Send at least three of each substrate.

Designing a test file that proves something

A colour chart proves the ink is wet. Build a target that proves the things you would otherwise discover in month two. One A2 or full-bed file can carry all of it.

Then ask for the job report. Any RIP that drove the print can state the resolution, pass count, quality mode and print direction it used. Without those numbers a sample is not reproducible — the operator may have run six passes at the slowest mode to make it look good, and you will price your jobs against a throughput you cannot achieve. Ask for the settings sheet to travel with the sample and for the same settings to be used in the acceptance test after installation.

One more request that costs the supplier nothing: a nozzle check pattern printed immediately before and immediately after the test job, both photographed. A head with three dead nozzles can still produce an attractive sample in six passes. The before-and-after pair tells you whether nozzles dropped out during the run, which is a different and more serious problem than a head that starts imperfect.

What to do with the samples when they land

Do not evaluate the sample on the day it arrives.

UV ink cure develops after the lamp. Adhesion measured ten minutes after printing tends to flatter, and adhesion measured after 24 to 48 hours is closer to what your customer will experience. Let the samples sit at room temperature for two days, then run the tests in a fixed order and write the results down.

1. Cross-hatch and tape. Score a lattice through the ink to the substrate, apply and remove pressure-sensitive tape, and grade the result. The recognised methods are ISO 2409 and ASTM D3359 — quote one of them by name in your contract so both sides are grading against a published scale rather than an opinion.
2. Thumbnail and scratch. Crude, immediate, and the test your customer will actually perform at the counter.
3. Flex, if the part flexes. Bend leather, soft PVC and thin composite through the radius the finished part sees. Rigid UV ink cracks; flexible ink formulations exist and are a specification question, not a machine question.
4. Measure the keyline with a steel rule or callipers on both axes and compare to the file dimensions.
5. Read the small type under a loupe — 4 pt reversed text is where head alignment shows up.
6. Leave one coupon on a south-facing windowsill for whatever period matters to your application, if lightfastness is part of the sale.

Photograph everything, including the failures. A dated photo set is the evidence base for the punch list you attach to the balance payment.

The video run-off, and what to ask for on camera

A demo video is easy to supply and easy to make meaningless. The version that carries weight has four features, and you should ask for them explicitly:

• One continuous unedited take covering load, print, cure and unload of a single sheet. Cuts are where the interesting parts go.
• The machine nameplate in the same take, showing the serial number that will appear on your packing list — not a nameplate filmed separately.
• A handwritten date card held to camera at the start, or the current day's newspaper if you prefer the classic. This is old-fashioned and it works.
• Your file on the screen, and the operator's RIP window visible when the job is submitted.

Ask whether that run-off can be scheduled live rather than recorded — a video call at a time you nominate, with the ability to ask for a different substrate to be loaded while you watch, is a materially stronger test than a file that arrives by WeTransfer. Whether a given supplier will do it is a question to put in writing, not an assumption. If your order size justifies it, a third-party inspector can attend instead; the mechanics of that are the same as any pre-shipment inspection in China, and the framework for witnessed equipment run-offs is set out in the factory acceptance test guide for machinery.

Common questions

Is a same-day sample the same thing as a pre-shipment test print?

No, and conflating them is a common error. Same-day sampling on standard models means the supplier can print your artwork on a stock configuration quickly, so you can see real output before you commit to an order. A pre-shipment test print happens after your machine is built, on your machine, with your substrate — it is an acceptance step, not a sales step. Use the first to decide whether to order, and the second to decide whether to release the balance.

The supplier says the substrate has to be tested at quotation stage, not at build stage. Is that unreasonable?

It is reasonable and you should do both. Testing early tells you whether the application is viable at all, and if it is not, you have learned that before spending money. Testing again on the finished machine tells you the specific unit you bought reproduces the result. The early test is cheap; skipping the late one is where the risk sits.

What if the test print fails?

That is the point of doing it while you still hold 70%. Failure is usually not fatal — it points at a primer, an ink family, a cure setting or a head-height problem, all of which are fixable before crating and expensive to fix afterwards. Write the remedy loop into the contract: a defect list within a set number of days, a re-run at the supplier's cost, and the balance falling due only after the re-run passes.

Can I ask for the test print if I am buying a single machine?

Machines in this category are commonly sold from one unit, so a single-machine order is a normal transaction rather than a special case, and a first-unit buyer arguably has more reason to insist. The request costs the supplier a few hours of a build engineer's time — the resistance you will meet is usually about scheduling, not principle.

Does UV ink adhere to everything?

UV-curable inks bond across a wide range of materials — acrylic, glass, metal, wood, PVC, leather and board are the families usually named — but "bonds to" and "passes a cross-hatch test after 48 hours on your specific lot" are different claims. Some substrates need a primer or pre-treatment. Ask which of your materials the supplier expects to need one, and get the primer named.

What to ask the supplier next

Send this list with your substrate consignment and keep the replies in the same file as the proforma invoice. The same discipline that produces a comparable quotation applies here — this is the acceptance half of the sample order process with a Chinese factory.

1. Does the test print gate the balance invoice? Confirm in writing that the run-off happens, and the report is delivered, before the 70% falls due.
2. Will the run-off be on my serial-numbered machine, with the nameplate visible in the video, rather than on a demonstration unit?
3. Who pays inbound freight and duty on the substrate I ship in, and are the offcuts returned or consumed?
4. Can the run-off be scheduled live on a video call at a time I nominate, with the ability to request a substrate change during the call?
5. Will the RIP job report — resolution, pass count, quality mode, print direction, ink volume — be supplied with the samples, and will the acceptance test after installation use the same settings?
6. Nozzle check before and after, photographed and dated.
7. Which of my listed substrates do you expect to require a primer or pre-treatment, and what is the product name?
8. Is the ink system open or chipped, which ink is the machine profiled for, and does the warranty depend on using it?
9. What is the remedy loop if a sample fails a cross-hatch test to ISO 2409 or ASTM D3359 — re-run at whose cost, within what window?
10. How are the printed samples returned to me, by which service, and how long does that leg take?

Longrun Printing Machinery is a reasonable example to run this list against. It is a Shenzhen manufacturer established in 2009 in Longgang district, working as a direct manufacturer with no trading-company layer, with a 40-person engineering and assembly team building roughly 300 machines a year across UV flatbed, corrugated-carton digital and cylindrical UV lines. Its published process places a test print of the buyer's files and substrates at step three, before export crating at step four; standard models are listed as sampleable the same day, a machine demo video is offered on request, and terms are quoted as T/T 30% deposit against 70% before shipment, on EXW, FOB or CIF, from one unit. What is not published — who carries the freight on your inbound coupons, whether the run-off can be booked live, and how the samples come back — is exactly the set of questions worth settling before the deposit rather than after the balance.