Backpack name tag
that survives the school bus
A backpack tag gets dropped, dragged and yanked every day. Print it in PETG or TPU, about 90 to 105 mm long with a thickness setting of 5 mm, and set the ring hole to 35% so a carabiner fits. Baloo 2 is preset because its round, heavy strokes don't chip.
By Philipp Baldauf · Updated September 29, 2026
Baloo 2 in keychain mode is preset. For a school bag you can print it at the size it comes out; no scaling needed.
The tag that makes it to summer
Most printed bag tags don't fail in the letters. They fail at the ring, in January, when a cold PLA tag hits the floor of the bus. So the recipe is simple: a tough material, a thick ring, and a hole big enough for proper hardware.
The generator helps with the size. At its default size, a four- to six-letter name in Baloo 2 comes out about 100 to 105 mm long and 29 mm tall, ring included. That's right for a school backpack, and at 100% the ring keeps a wall of 3 mm or more around the hole. Just print it as it is. The plate is 2 mm deep with its top at 2.5 mm, and the letters stand on top.
PETG vs PLA vs TPU for a school year
| Material | Lasts a school year? | Heat | Drops and cold | Printing | Pick it if |
|---|---|---|---|---|---|
| PLA | often not | softens from about 55 to 60 °C | brittle when cold, cracks at the ring | easiest | it's a class project or stays indoors |
| PETG | yes | fine to about 70 °C | tough, bends before it breaks | easy, a bit stringy | you want one default choice |
| TPU 95A | yes, almost unbreakable | handles a hot car | bends and springs back | slow, 20 to 30 mm/s, direct drive | the bag gets thrown around a lot |
A bag left in a car or at a sunny window easily passes 60 °C in summer, which is where PLA starts to sag. PETG is the safe default. TPU is best, but it's harder to print and the letters come out a little softer at the edges.
Make the ring hole last
Four settings and one hardware choice decide whether the tag survives.
A bigger hole gives a thicker ring
The ring wall is at least 3 mm, or 80% of the hole radius if that's more. Set Ring Hole to 35 to 40% and you get a hole of about 10 to 11 mm at default size, with a wall of over 4 mm around it.
A thicker plate
The ring is as thick as the plate. With a thickness setting of 6 to 7 mm the plate top rises to 2.9 to 3.3 mm, so the ring gets thicker too. The tag is then 8 to 10 mm thick, which is fine on a backpack.
More walls
5 or 6 wall loops make the ring and the letters solid plastic. Infill barely matters at this size. More slicer tips are in keychain slicer settings.
Print flat and hot
The file lies flat, so layers run along the tag, which is the strong direction. Print PETG at the upper end of its range, around 245 to 250 °C, for better layer bonding.
Proper hardware
Use a small steel carabiner or a screw-lock cable loop, like on luggage tags, and clip it to the bag's strap loop. A split ring straight on a zipper pull wears through the pull within weeks.
Sizes for bags, cases and lunch boxes
Typical values in PETG at 0.2 mm on a Bambu Lab A1 mini or similar. Scale X and Y only, leave the height at 100%.
| Where it goes | Length | Thickness setting | Ring Hole | Print time |
|---|---|---|---|---|
| School backpack | 90 to 105 mm, default size | 5 mm | 35 to 40% for a carabiner | about 40 to 60 min |
| Sports or gym bag | 100 to 110 mm | 5 to 6 mm | 35 to 40% | about 50 to 70 min |
| Pencil case zipper | 50 to 60 mm, scaled to 55% | 3 mm | 30% | about 20 min |
| Lunch box or bottle | 60 to 70 mm | 3 mm | 25 to 30% for a split ring | about 25 min |
A default-size tag in PETG weighs about 9 to 12 g, roughly 25 cents of filament. How the length changes with longer names is in the keychain size guide.
Safety for young kids
A bag tag with a split ring is not a toy, and it's not for children under 3. The ring can be pried open, and a tag that snaps makes small pieces a toddler can swallow. For a daycare bag, hang the tag where the child can't reach it, or use a sewn label instead. Printed plastic isn't certified as toy-safe or food-safe, so it shouldn't end up in a mouth.
Think about privacy too. A name you can read from across the playground lets a stranger call your child by name. Many parents use only the first name, initials, or hang the tag inside the bag flap. Don't put a phone number or address on the outside.
From name to finished tag
- 1
Type the name
Baloo 2 is preset and reads well for kids who are just learning letters. For older kids, Anton looks sportier; script fonts are covered on the cursive name keychain page.
- 2
Set thickness 5 mm and Ring Hole 35%
Then pick the colours. Bright letters on a dark plate are easy to spot in a pile of identical backpacks.
- 3
Download and print in PETG
Designing is free; a single download costs $4.99 (see pricing). Print flat with 5 walls. For two colours on a printer without an AMS, add one pause where the letters start, as in multicolour without an AMS.
- 4
Clip it on
Carabiner through the ring, carabiner onto the strap loop at the top of the bag. Done in a minute.
Tags for the whole class
Teachers and parents often print a tag for every child at the start of the year. With Unlimited ($9.99 a month) you can export up to 100 names at once as one ZIP, and print 4 to 6 default-size tags per A1 mini plate. The bulk name keychain page walks through it, and 3D printing projects for kids has ideas where the children design their own. For cubbies and lockers there are locker name tags.
Questions people ask
What's the best material for a 3D printed backpack tag?
PETG. It handles a hot car, doesn't turn brittle in winter and bends before it breaks. TPU is even tougher but slower to print. PLA works for indoor use or a class project, but tends to crack at the ring within a school year.
How do I attach a printed name tag to a school bag?
With a small steel carabiner or a screw-lock cable loop through the ring, clipped to the strap loop at the top of the bag. Set the Ring Hole to 35 to 40% so the carabiner fits. Avoid hanging a split ring straight on a zipper pull, which wears through quickly.
Are 3D printed bag tags safe for toddlers?
Not as something they can reach. A tag with a split ring is a choking hazard for children under 3, and printed plastic isn't certified toy-safe. For daycare bags, hang it out of reach or use a sewn label.
How big should a backpack name tag be?
About 90 to 105 mm long and 25 to 30 mm tall, with a thickness setting of 5 mm. That's what a four- to six-letter name in Baloo 2 measures at the generator's default size, so you can print it without scaling.
Can I add the class or a second line?
Yes, the generator takes up to 5 rows of text, so a class like 3B fits under the name. Keep phone numbers and addresses off the outside of a child's bag.
How long does a backpack tag take to print?
About 40 to 60 minutes for a default-size tag in PETG at 0.2 mm, and 9 to 12 g of filament. Four to six fit on an A1 mini plate, so a small class batch runs overnight.