Card thickness and lamination: 0.40 to 1.0 mm, and why cards fail

A card looks like a piece of plastic. It is a stack of five, fused under heat and pressure, and almost everything that goes wrong in the field is a place where that fusion was incomplete or was later broken.

Thickness gets specified casually, usually by copying whatever the last order said. It is worth more attention than that, because thickness is one characteristic of a layered product, not a specification on its own. The complete construction decides whether the card fits an encoder, a holder and a wallet, how it feeds, and how long it survives.

The two subjects belong in one guide because they are the same subject seen from two ends. Thickness is what the stack adds up to; lamination is what holds the stack together. Specify the first without understanding the second and you end up with a card that is the right size and falls apart, which is the more expensive of the two failures because it happens after the cards are in circulation.

This guide is for whoever writes the specification: a trade printer, a distributor, an integrator or a programme owner.

01. What a card is made of

Five layers, in a fixed order, pressed together in a lamination press.

Two things follow from the diagram and both matter commercially. The first is that the print is protected, not exposed. The second is that the inlay is in the middle, so anything that presses on the card from outside, an embossed character, a hot foil block, a punched slot, has to avoid the area where the chip and antenna sit.

This is the difference between a laminated card and a desktop printed one, and it is worth explaining to a client who is comparing prices. A card printed on a desktop machine has its image on the surface, under a thin ribbon overlay at best. A laminated card has its image sealed between layers of PVC. The first looks equivalent on the day it is issued. Six months later, in a pocket, they are not the same product.

02. The number that matters is 0.76 mm

ISO 7810 defines the ID-1 format as 85.60 by 53.98 mm, 0.76 mm thick. That thickness is not a style choice. Every encoder feed, every card printer, every wallet slot and every card holder in the world is built around it. The width, height, corner radius and tolerances that go with it are covered in the guide to CR80 dimensions and tolerances.

Below 0.76 mm

Thinner cards are cheaper and lighter and are right for anything short lived or handed out in large numbers. They flex more, which means the area around the chip works harder, and they will not run through a card printer designed for the standard.

Above 0.76 mm

Thicker cards feel substantial and leave room for a larger inlay. They also stop fitting standard holders. Wooden cards sit outside the range entirely at 1.20 to 1.30 mm, which is a real operational consideration rather than a detail, and it is covered in the guide to wooden cards.

Ask the encoder, not the designer

If the card has to pass through a printer, an encoder or a dispenser, that machine sets the thickness and there is no discussion to have. Specify anything else only where the credential is handled by people rather than by machines.

One practical test settles most of these conversations. Ask what machine the card has to go into, and whether anybody has tried a non standard thickness in it before. If the answer is a hotel encoder, a desktop card printer or a vending style dispenser, the thickness is decided. If the card is only ever handled by people, tapped on a wall reader and carried in a wallet, there is room to choose.

03. What lamination actually does

Heat, pressure and time. The stack goes into a press, the PVC softens, the layers flow into each other, and then it cools under pressure so the bond sets. Three variables control the result: the temperature, the pressure, and the dwell time.

Get them right and you have one piece of plastic. Get the dwell time slightly short and you have five layers that are stuck together rather than fused, which looks identical on day one and separates in month four. This is why a sample proves colour and feel but does not prove durability, and why the lamination recipe is one of the things worth writing into the specification record for the next order.

The cooling stage deserves a mention of its own, because it is the one most often rushed. A stack pulled out of the press while still warm relaxes, and the internal stress that leaves behind is what turns into a curve on a warm day months later. Cooling under pressure is not a finishing touch; it is half the process.

How to test a sample properly

Because none of this is visible at delivery, the only useful sample test is a deliberately abusive one, run on cards that represent the finished construction rather than on an unlaminated proof. Flex a card fifty times along its long axis and look at the area over the chip. Leave one on a windowsill in the sun for a week. Carry one in a back pocket for a few days. Try to lift a corner of the overlay with a fingernail. Five minutes of effort spread over a week tells you more about a supplier than any specification sheet.

04. Four ways a card fails

Edge separation

The overlay lifts at a corner and the card starts to peel. Lamination is the usual finding, and it shows up first on cards that live in a pocket with keys, but the finding belongs to the investigation rather than to the symptom.

Cracking at the chip

The chip module is the stiffest point in an otherwise flexible card, so repeated bending concentrates there. More common on thin bodies, more common again where the card is carried in a back pocket. It is also the failure most often blamed on the chip when the body is what moved: the silicon is usually intact, the connection between module and antenna is not.

Print wear

The image fades where the card is gripped. A thin overlay, or no overlay at all on a surface printed card, and the card looks tired in months.

Warping

PVC softens well below its melting point. A dashboard in summer, a pocket next to a body all day, a hot wash, and the card takes a curve it does not lose. A warped card often still reads, but it stops feeding through machines, which is a different and more annoying kind of failure. PET handles heat considerably better, which is usually the reason it gets specified.

05. Specify the construction, not just the thickness

A specification that says 0.76 mm and nothing else has described one number out of a dozen that matter. Record the finished dimensions and the layer proposal together, and name every feature that interrupts the stack, because each one changes how the card behaves in a feeder.

• Finished dimensions and thickness, and whether the card has to pass through a printer, encoder or dispenser.
• The core: standard PVC, recycled PVC, PET, or a wooden body.
• The layer reference: overlay on one or both faces, gloss or matt, and the inlay if the card carries a chip.
• Anything pressed or cut: embossing, hot foil, a punched slot, a signature or scratch panel, and whether each one clears the inlay.
• The environment: pocket, wallet, lanyard, vehicle, wet area.

The last line is the one most often left out and the one that predicts the most failures. A card that lives on a lanyard around a neck all day is a different product from one that lives in a wallet and comes out twice a week, even though the specification sheet looks the same. Say where the card lives and a manufacturer can tell you which of the four failure modes is the one to design against.

Do not choose thickness from appearance alone, and do not assume a thicker card is the more suitable one. Raised features show why. Embossing displaces material rather than removing it, so the card is not thinner where it is embossed, but the area is stressed and it has to clear the inlay: send the embossing positions with the artwork so the inlay layout can be chosen around them.

Treat a construction change as a change

Any change to the layers, the thickness or a pressed feature should go through the same controlled approval used for any other critical requirement, and it should be retested as a complete item. An approval given for the previous construction does not carry over, because what was approved was a stack, not a number.

06. What counts as evidence when something fails

Those four are different symptoms and worth keeping apart in writing. A visible defect does not prove how it was made; it tells you where to look. Two things separate a supportable claim from an argument.

The first is agreeing the test conditions before the run, on representative finished samples, so both sides measure the same thing when a complaint arrives. The second is preserving the evidence: keep the failed cards themselves, not photographs alone, and the lot reference that goes with them. A handful of cards from a known lot, plus the conditions they were used in, is what lets a factory pull the press record for that run. The same discipline applies on arrival, and the delivery inspection checklist sets out what to check before a delivery is accepted.

Before you approve

A short list, worth confirming in writing rather than assuming:

• Finished dimensions, including thickness, measured on production cards.
• The layer reference for the approved construction.
• Equipment fit, confirmed on the actual printer, encoder or dispenser.
• The durability tests that are relevant to where the card will live.
• How failure evidence will be gathered and retained if there is a problem.

One of these is quick enough to be worth doing on every delivery. Thickness should measure the same at every edge, and a card that does not is a lamination problem a caliper gauge finds in seconds, which is why checking a few cards from a pallet earns its time.

07. Worked example

Illustrative scenario, not a Kaway case study. A 0.76 mm card has been running through a hotel encoder for two years without complaint. A new print run adds an embossed member number to the front. The cards come back the right thickness, correct to the drawing, and the encoder starts to misfeed.

Nothing about the thickness changed. The stack is no longer flat: the embossed characters stand proud of the surface and the cards no longer sit down in the hopper. The original approval covered a construction without a raised feature, so it did not cover this card. The fix is procedural rather than technical: retest the revised construction as a complete item, on the machine it has to feed, before committing the full quantity. Ten cards and an afternoon at the property would have caught it.

08. Technical references

• ISO/IEC 7810, identification cards and physical characteristics, which is where the ID-1 format and its 0.76 mm nominal thickness are defined: iso.org/standard/70483.html.

09. Where Kaway fits

We manufacture for the trade and do not sell to your customers. PVC and recycled PVC cards from 0.40 to 1.0 mm are printed, laminated, die cut, personalised and encoded in one place: Kaway manufactures at the plant in Dongguan, China, which is what makes the lamination recipe something we can reproduce on a reorder rather than rediscover.

Minimum order is 500 units. Standard production is 13 calendar days, 8 calendar days on express and 12 calendar days for wooden cards. Quote requests are answered the same working day. A free sample goes out before any order, and the honest advice is to treat it roughly for a week before deciding. What a factory needs in order to quote is in the guide to specifying an order.

Discuss your card construction and equipment requirements with Kaway Group.

10. Frequently asked questions

What thickness should I order?

0.76 mm unless you have a specific reason not to. It fits every machine and every holder, and departing from it should be a decision rather than an accident.

Can a thin card carry a chip?

Yes, down to about 0.50 mm comfortably. Below that the inlay choice narrows and the card flexes enough that the area around the chip becomes the weak point.

Why did our last batch start peeling?

Lamination is the usual finding: temperature, pressure or dwell time slightly off. It behaves like a process problem rather than a materials problem, which is why it can appear on one run and not the next from the same supplier. Keep the peeling cards and the lot reference so the press record for that run can be checked.

Does a recycled core laminate the same way?

Yes. Same process, same equipment, same result. What a recycled core does and does not change is covered separately.

Can you match the thickness of our existing cards?

Send one. Measuring it and matching the stack is straightforward, and it removes the single most common source of a card that suddenly will not feed.

Is a matt or a gloss overlay more durable?

Gloss hides scratches better because it reflects unevenly. Matt shows wear sooner but hides fingerprints, and it is usually chosen for how it looks rather than how it lasts. Neither changes the structural durability of the card, which is decided in lamination.