Design and 3D print a name keychain in Tinkercad

Design a keychain with your name on it in Tinkercad, free in the browser, then slice it and print it: most people's first real 3D print.

Age 8 and up. About an hour to design, 30 to 45 minutes to print. Starter level.

What you need

A computer with a web browser, and a free Tinkercad account (under 13s sign up with a parent or teacher)
Access to a 3D printer and PLA filament: at home, at school, or at a local print service
Slicer software for your printer, such as Cura or PrusaSlicer (both free)
A key ring

Make the base
Start a new design. Drag a box onto the workplane and set it to 50 mm long, 20 mm wide and 3 mm tall. Round its corners using the radius setting, so it's comfortable in a pocket.
Add your name
Drag the text shape onto the base and type your name. Set its height to 2 mm and lift it to sit on top of the base, so the letters stand 2 mm proud. Pick a chunky font: thin letters break or don't print.
Make the hole
Drag a cylinder to one end, set it to 4 mm across and taller than the base, and change it to a hole. Leave at least 3 mm of material around it, or the ring will tear through.
Group it and check
Select everything and group it. Look at it from every side: are all the letters touching the base, and is the hole all the way through? Anything floating won't print.
Export and slice
Export the design as an STL file and open it in your slicer. Good starting settings for PLA: 0.2 mm layer height, 20% infill, nozzle 200 to 210 °C and bed 60 °C. The slicer shows how long it will take and how much filament it uses.
Print it
Watch the first layer go down: it should be flat and stuck firmly to the bed. When it's finished, let the bed cool before you take it off, then thread on the key ring.

The nozzle and the bed are hot enough to burn. Keep hands away while it prints and until it has cooled.
Print in a room with some fresh air, and use the printer the way its owner shows you.

The first layer won't stick: Clean the bed, check it's level, and make sure the bed is at temperature before printing starts.
The letters came out messy: Make the text taller and bolder, or slow down the print speed for small details.
The hole closed up: Make it a little wider, 4.5 mm, as printed holes come out slightly smaller than drawn.

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