Will a 3D printed QR code actually scan?
Yes, but the reason it works is worth understanding, because it is where most printed codes fail. A phone camera reads a QR code by contrast, not by relief. A code printed in a single colour has no contrast at all — it relies on the shadow cast by the raised modules, which means it scans in angled light and stops scanning under a flat ceiling light.
Two things fix this. The reliable one is two colours: print the plate in one filament and the code in another, either as two separate files that fit together or as a 3MF that a multi-material printer handles in one go. The other is to engrave the code and fill the recess with paint or resin. Both give you real black-on-white contrast, and both scan the way a printed code should.
The second factor is size. A module — one square of the code — should be at least 1.2 mm across for a typical phone. The tool shows you the module size as you resize the plate and warns you when you drop below that, because a 25 mm plate holding a long URL produces modules under half a millimetre that no camera will resolve.
Printing a WiFi QR code that works
A WiFi QR code is not the password written as a code. It is a specific string that tells the phone the network name, the security type and the password in a format the operating system recognises, so that scanning it offers to connect rather than just showing text.
Three details break it more often than anything else. The security type has to match: WPA covers WPA, WPA2 and WPA3; an open network needs its own setting and no password at all. Special characters in the network name or password — semicolons, colons, commas, backslashes — are separators in the format and have to be escaped, or the phone reads the string cut off at the wrong place. And a hidden network needs to be flagged as hidden, otherwise the phone looks for a network it cannot see.
The tool handles all three. You fill in the fields, it builds the string. Scan the preview with your own phone before you print — that is the only test that counts.
Error correction: which level to choose
Every QR code carries redundant data so it still reads when part of it is damaged. There are four levels — L, M, Q and H — recovering roughly 7%, 15%, 25% and 30% of the code respectively.
More correction is not free: it makes the code denser, so at the same plate size each module gets smaller. On a printed piece that trade goes the wrong way surprisingly fast. A vCard at level H can push a 60 mm plate to modules under a millimetre, which is worse for scanning than the scuffs the extra correction was protecting against.
M is the right default for a printed code. Go up to Q or H only for a piece that will be handled hard — a keychain that lives in a pocket — and only if you can afford the extra size to keep the modules above 1.2 mm.
Print settings
Print the plate flat on the bed, code facing up. No supports are needed for any of the options — the ring, the magnet recess and the stand are all designed to print without them.
0.2 mm layers are plenty. With a raised code and a 1.2 mm code height, that is six layers of modules, which is more than enough definition. Going finer costs time and gains nothing a camera can see.
For the two-colour version, a single-extruder printer handles it with a filament change: print the plate, pause at the layer where the code starts, swap the spool, carry on. Your slicer will insert the pause for you. On a multi-material printer, use the 3MF — the colours are already assigned to filament slots.
If you engrave the code and plan to fill it, print the recess at least 0.6 mm deep and let the paint dry fully before wiping the surface flush.