4B EngraverSerial numbers and batch personalisation for 3D printed parts
To serialise a run of 3D printed parts, engrave the number into a flat face in the format PREFIX-0000 and let the tool do the counting. 4B Engraver at /app generates N copies with consecutive serials and returns them as a single zip, so fifty numbered parts are one upload rather than fifty edits.
The second decision matters as much as the first: put the serial under the logo on the logo face, and leave the other face free. Crowding logo, name and serial onto one face of a small part pushes every line down to about 3.0 mm cap height with 0.85 mm strokes. Split them, and the serial sits at 4.1 mm while the name gets a whole face to itself.
Why put a serial number on a 3D printed part?
- Asset tags. Tools, jigs and fixtures that live in a workshop need an identity that does not peel off.
- Traceability. The serial ties a physical part back to your record of revision, filament and print date.
- Numbered runs. In a limited run, the number is what separates one copy from the next.
An engraved recess is geometry rather than something applied on top, so there is nothing to peel or rub off, and it arrives with the part rather than as a second operation.
What does the PREFIX-0000 format actually mean?
The serial is a prefix you choose, then a hyphen, then a zero-padded four-digit number: 4B-0042. The prefix takes up to six letters or digits, and you can leave it empty for plain numbers. The padding keeps every serial in a run to the same character count, so the engraved line stays the same length from the first part to the last and the numbers sort correctly in your own records.
How do I generate a numbered run?
Batch mode takes a count and produces that many parts with consecutive serials, delivered as one zip. Each part takes roughly 3 to 10 seconds to generate, and every copy goes through the same checks as a single part: the mesh is verified watertight, and each engraved floor is verified to exist at the requested depth, with a floor area of at least 80% of the intended shape area.
Download the zip and archive it: generated files are deleted from the server after 7 days, and a batch is not something to regenerate from memory six months later.
Where should the serial go on the part?
The logo face carries your logo, optionally with the serial underneath it. The personal face carries exactly one of a name, a serial number or a logo. That split is deliberate: a serial is short, a name is not.
| What is engraved | Face and orientation | Cap height | Narrowest stroke |
|---|---|---|---|
Serial 4B-0042 under the logo | 1 m C-to-C winder, second face | 4.1 mm | 0.85 mm |
| Logo + name + serial on one face | 1 m C-to-C winder, single face | 3.0 mm | 0.85 mm (thickened) |
| 7-letter name, upright | 1 m C-to-C winder, oval face | 4.4 mm | 0.9 mm |
| 7-letter name, rotated | 1 m C-to-C winder, longest clear strip | 8.3 mm | 1.7 mm |
| 7-letter name, rotated | MagSafe spooler face | 9.6 mm | not recorded |
The rotated rows are the point. Text height on a flat face is limited by width, not height, so letting Auto orientation run the text along the longest clear strip nearly doubles the cap height on the same part. There is more on the limits in the minimum text size guide, and on placing artwork in the logo guide.
How deep should a serial be cut?
Leave the depth at the 1.2 mm default; the full range is 0.6 to 2.0 mm, and the depth guide covers the trade-offs. What matters for a batch is the wall check. Before cutting, the tool measures the material remaining under the engraved glyphs, using a 0.3 mm halo around the shapes rather than the bounding box, and refuses any depth that would leave less than depth plus 0.8 mm of wall. On the bundled winders there is room to spare: 16.4 mm of material under the logo area on the 1 m C-to-C winder, about 39 mm on the MagSafe spooler. The check only bites on thinner parts of your own.
How do I print a numbered batch on one plate?
- Pick the format for the job. STL is right when you are mixing several different parts on one plate, or slicing outside Bambu Studio. 3MF is right when you want the designer's print profile and paint-on supports to survive: the 1 m C-to-C winder carries 2,494 painted-support triangles and the MagSafe spooler 2,812, and an STL carries none of that. The format comparison covers what happens when that data goes missing.
- Watch the file sizes. The 1 m winder is 7.9 MB as 3MF and 27.6 MB as STL. The MagSafe spooler is 26.8 MB as 3MF and about 60 MB as STL, at 1.99 million triangles. A plate of copies in STL form is a lot of geometry for a slicer to hold, so open the 3MF unless you have a reason not to.
- Keep the serials in plate order. Lay the parts out in the order the zip lists them, so a photograph of the plate records which number is where.
- Log the run as you pack. Serial, recipient or location, filament, print date. Do it at packing time, because once identical parts are in a box the engraved number is the only thing telling them apart.
Try it on your own model. Upload an STL or 3MF, add a logo, a name or a serial number, and download a print-ready file.
Open the engraver — freeFrequently asked questions
What is the smallest serial number text that still prints cleanly?
The limit is stroke width, not height. On a 0.4 mm nozzle a recessed stroke must be at least 0.8 mm wide or the perimeters merge and the groove fills in. A serial measured on the 1 m C-to-C winder sat at 4.1 mm cap height with 0.85 mm strokes. Anything under 2.5 mm cap height triggers a warning in the interface, which is the point to move something to the other face.
Can I use my own prefix, or is it numbers only?
Both. The format is PREFIX-0000, where the prefix is up to six letters or digits that you set, giving serials like 4B-0042. Leaving the prefix empty produces plain numbers instead. Keeping the prefix short leaves more width for the digits, which matters on small faces where text height is limited by the available width rather than by height.
Does batch mode change anything besides the number?
No. Batch mode takes a count and produces that many copies with consecutive serials, delivered as one zip. Every copy goes through the same checks as a single part: the mesh is verified watertight, and each engraved floor is verified to exist at the requested depth with at least 80% of the intended shape area. Generation takes roughly 3 to 10 seconds per part.
Should I export STL or 3MF for a batch plate?
Use STL if you are mixing several different parts on one plate or slicing outside Bambu Studio, since STL is geometry only and drops cleanly into any slicer. Use 3MF if you want the designer's print profile, plate layout and paint-on supports preserved. Watch the size: the MagSafe spooler is 26.8 MB as 3MF but about 60 MB as STL, so a large plate of STLs gets heavy fast.
Where should the serial sit if I also want a name on the part?
Put the serial under the logo on the logo face and give the name the other face on its own. Crowding logo, name and serial onto one face of the small winder dropped every line to about 3.0 mm cap height with thickened 0.85 mm strokes. Split across two faces, the serial holds 4.1 mm and a rotated seven-letter name reaches 8.3 mm on the same part.
How long are my generated batch files kept?
Generated files are deleted from the server after 7 days, so download the zip and archive it locally as soon as the batch finishes. Keep it alongside your own record of which serial went to which customer, location or print date. Once identical parts are boxed, the engraved serial is the only thing telling them apart, and regenerating a run from memory is error-prone.