Choosing an RFID card manufacturer: the twelve questions to ask before you order

Three quotes for the same card, from three factories in the same Chinese province, can differ by a third on unit price and still describe a product identical on paper. All three say MIFARE compatible, 13.56 MHz, CR80, 0.76 mm, four colour both sides. Nothing in those lines tells you which of them will still open your customer's doors in eighteen months. The difference is rarely in the price. It is in what the quote leaves out: which silicon is in the inlay, who laminates it, where the encoding happens, and who pays when a lot is wrong.

What follows are twelve questions to put to any RFID card manufacturer before you release a purchase order, with why each one matters and what a weak answer tells you. Send them by email and keep the replies.

01. Why three quotes for the same card never match

A quote for custom RFID cards is the visible end of about fifteen decisions, and only four or five of them appear in writing. The chip alone can swing the unit cost by a factor of five, since a 48 byte Ultralight EV1 and a DESFire EV3 8K are both 13.56 MHz cards and nothing else about them is comparable. Copper wire wound, aluminium etched and printed ink antennas all read, but not at the same distance or yield. Add the layer build, the encoding labour, the inspection level, the tooling and the freight. The questions below pull each of those into writing.

02. The plant: questions 1 to 3

Everything else depends on this group. If you do not know where the card is physically made, nothing you agree about the chip has an address to be enforced at.

Question 1. Do you own the plant where these cards will be laminated?

Ask it in those words, then ask for the plant address, the headcount, the monthly capacity and photographs of the lamination presses rather than a showroom. A trading company talks about our factory without ever naming it. This is not snobbery about brokers, it is about who can change your specification. An intermediary buys on price per thousand, and when its supplier raises the chip cost, the cheap fix is a different chip in an identical looking card.

Question 2. Is the encoding done in this plant, by your staff?

Encoding is where your keys, your numbering and your UID list exist in plain form. If cards are laminated in one place and encoded in another, all of it travels between them. Ask who holds the keys, how they are transmitted, whether they are deleted after the run, and whether the encoding report comes from the machine that performed the write. In the same plant, a failed card is pulled before packing and traced to its lamination lot.

Question 3. What lot traceability do you keep for the chip, the inlay and the PVC?

A serious factory can tell you six months later which inlay lot and which PVC batch went into the cards delivered on a given date. That record turns a field failure into a bounded problem instead of a recall of everything you bought. Ask for the format: a lot number on the carton label, recorded against the sales order, is the minimum. If all material simply comes from good suppliers, there is no traceability.

03. The chip and the reader: questions 4 to 6

This group causes more failed deliveries than everything else combined, and nearly all of them are avoidable before production starts.

Question 4. What is the exact chip, by name and part reference?

Not MIFARE compatible, and not 1K card. The answer should read like a part number: MF1S50yyX/V1 for MIFARE Classic EV1 1K, MF0UL1101 for Ultralight EV1 with 48 bytes of user memory, MF3D8301 for DESFire EV3 8K, NT2H1511 for NTAG215, ATA5577C for a rewritable 125 kHz card. Ask for the UID length too, since a 7 byte UID is not interchangeable in a reader configured for eight hex characters. Compatible usually means clone silicon that differs in ATQA and SAK response, key handling or write timing, as our MIFARE chip comparison guide sets out.

Question 5. Will you confirm compatibility against my reader or lock, in writing, before production?

This is the question that separates suppliers. The honest process: you send the reader and lock model with its firmware version, or two cards that already work, and the factory tests and then states in writing which chip it will use and that it verified a read. That statement is what you hold if the lot fails. Yes it works, no problem, from a supplier who never asked what you read with, is a guess. Hotel systems are the worst case, since many read one sector of MIFARE Classic with proprietary keys and ignore a technically better card. The hotel key card compatibility guide covers that check.

Question 6. If a delivered lot does not read, who pays for what?

Ask for the remedy in writing before the purchase order. There are three separate costs: replacement cards, freight on the replacement, and the failed cards sitting in your warehouse. A factory that confirmed the chip in writing and got it wrong should carry all three. A factory given an unverified specification by you carries the first only, and that is fair. What you are testing is whether the supplier distinguishes the two cases.

04. The card as a physical object: questions 7 to 9

Thickness is the only physical property most quotes state, and alone it tells you little.

Question 7. What is the card built from, layer by layer?

Ask for the stack: overlay thickness and finish, print sheet thickness, inlay type and thickness, and the total with tolerance. Ask what the antenna is and what the inlay is tuned to, since a card tuned for a long range desktop reader behaves differently against a wall mounted lock antenna. Then ask about the lamination cycle and whether cards are cooled under pressure, which decides flatness and whether the layers separate after a year in a pocket. Our thickness and lamination guide explains why 0.76 mm against 0.84 mm stops being a preference once the card must fit a punched slot.

Question 8. What acceptance criteria will you inspect this lot against?

There is a correct answer here and it is numeric. Electrical function should be verified on every card, read and, where encoded, read back after writing. Cosmetic and dimensional defects should be sampled against a stated plan, normally single sampling under ISO 2859-1 at general inspection level II, with the AQL written down and critical defects at zero acceptance. Ask what counts as a defect: colour deviation beyond an agreed tolerance, registration drift, specks, edge burr, warp beyond the flatness limit. Then ask who signs the report. We check everything carefully is not a criterion.

Question 9. On a repeat order, what exactly do you lock so lot two matches lot one?

Ask the supplier to name what it freezes: chip part reference including revision, inlay supplier and tuning, PVC supplier and grade, ink set with measured colour targets, overlay finish, lamination recipe, and the die if the shape is not standard. Then ask for a retained reference sample, signed by both sides and held against the sales order with its lot number, and that the next lot be checked against that physical card rather than the artwork file.

05. The commercial terms: questions 10 to 12

These three decide what the quoted number becomes by the time stock reaches you.

Question 10. What does the price include, and what will I be invoiced for later?

Is a cutting die needed for the shape, what does it cost and who owns it afterwards. Are pre production samples charged, and made on the line or assembled by hand, since a hand built sample proves nothing about the lamination recipe. Then fix the Incoterm with its named place, so you know where cost and risk transfer. Freight is arithmetic: a PVC card weighs roughly five grams, so ten thousand cards are about fifty kilos in half a cubic metre of cartons. Duty is yours to confirm with your broker against the correct classification for chip cards.

Question 11. Do you sell to my customers?

If you are a distributor, a printer or an integrator, ask it plainly, with three follow ups. Will any marking, logo or sticker from the factory appear on the card, the box or the paperwork. Will the factory quote directly to an end user who contacts it with your artwork. Will your artwork and your customers be used as portfolio material. A supplier that genuinely works white label answers all three without hedging and puts it in the sales contract.

Question 12. What documents travel with the shipment?

Ask for the list before you order. A complete set includes a packing list with carton counts and lot numbers, the encoding report or UID list in a readable file, the read test result, the inspection report, a materials declaration, the commercial invoice with the classification used, and for wood cards the chain of custody claim with its certificate code. These let you inspect on arrival instead of on complaint. A supplier that cannot describe its own paperwork is telling you nothing was recorded during production.

06. Scoring the answers you get

Put the three suppliers in three columns and score each answer as specific, vague or evasive. Count the specifics, not the tone: a factory that answers nine of twelve with part numbers and figures is lower risk than one that answers twelve of twelve with reassurance. Weight questions 1, 4, 5 and 9 heavily. Everything else is recoverable, and a card that does not open the door is not. Then ask for one sample made on the line, encoded as the lot will be, and tested against your own reader before volume is released.

07. Technical references

• Initialization and anticollision for contactless cards, which is where UID length and the ATQA and SAK response bytes are defined, the layer most compatible chips differ at: iso.org/standard/73598.
• Sampling procedures for inspection by attributes, the standard that turns an acceptance criterion into a number instead of an opinion: iso.org/standard/85464.
• The manufacturer page for the MIFARE chip family, where the part references quoted above can be checked against datasheets: nxp.com/products/rfid-nfc/mifare-hf.

08. Where Kaway fits

We wrote this list from the answering side. Kaway makes RFID and NFC cards, ABS key fobs, wristbands and printed accessories in our own plant in Dongguan, Guangdong, with our office in Hong Kong. Production has run in that plant since 2007, and Kaway Group Limited was incorporated in Hong Kong in 2015. The plant is 1,300 square metres with 87 people and a capacity of 8 million cards a month, and we have shipped to 53 countries.

The practice behind question 5 is our default: you send the reader or lock model and we confirm the chip in writing before anything is produced. We work across 125 kHz, 13.56 MHz and UHF, with MIFARE Classic, Ultralight, Plus and DESFire, NTAG, ICODE, EM4200 and T5577, on PVC, recycled PVC, PET, wood (basswood, cherry, black walnut) and bamboo. Encoding is done in the same plant. The FSC chain of custody certificate FSC-C195226 covers our wood lines, and we keep it off documents for cards it does not cover.

Minimum order is 500 units. Standard production is 13 calendar days, 8 on express and 12 for wood cards. Quote requests are answered the same working day, and a free sample follows once the request is qualified. Everything is white label: no Kaway marking on the card, the box or the documentation, and we do not sell to our distributors' customers. The equipment and the process are on the plant page.

09. Frequently asked questions

What is the minimum order for custom RFID cards?

500 units at Kaway, counted per design and per encoding configuration. Two artworks on one purchase order are two runs through print and collation, so they count separately.

Can a manufacturer confirm chip compatibility without me shipping a reader?

Often yes. The lock or reader brand, model and firmware version is usually enough to identify the chip and configuration needed. When the system is proprietary or poorly documented, the fastest route is two cards that already work, which we read and profile before quoting.

Is a MIFARE compatible chip the same as a MIFARE chip?

No. Clone silicon emulates the air interface but can differ in the ATQA and SAK bytes, in UID length and behaviour, in key handling and in write timing. The readers that reject it tend to be access control and hotel systems.

Should I buy blank cards and encode them myself?

If you hold the keys, run your own numbering and already own the encoders, in house encoding gives control and a shorter reorder cycle. Otherwise factory encoding with a returned UID file and a read test is cheaper and less exposed to a mis keyed batch.

How do I make sure a reorder is identical to the first lot?

Insist on a specification sheet listing chip part reference, inlay type, layer build, overlay finish and colour targets, and on a retained reference sample signed by both parties and held against the sales order. The next lot is checked against the physical card.

Which of the twelve questions matters most if I only ask one?

Question 5. Written confirmation of the chip against your actual reader or lock, before production starts, prevents the one failure mode a discount cannot fix.