Printurtle – Python to 3D print

1 Before the day

Printer settings. In More → Settings, check the printer is Creality CR-6 Max (400 × 400 × 400) and the profile is CR-6 Max – PLA (recommended). The keyring batch profile is there too.
Level the bed. On the printer, heat the nozzle and bed, clean the nozzle tip, and run a full bed levelling (mesh). Printurtle's files load that saved mesh with M420 S1; they never probe the bed when parts are on it.
Pause command. The two-colour keyrings pause with M600. If your printer ignores it, choose M0 in Settings → 3D printer and G-code → Pause command.
Test print. Print one keyring with a raised name (Quick make → Make it and set up printing) and watch the priming line, the first layer and the pause. If no plastic comes out at the priming line, see Problems and fixes below.
Every laptop: open printurtle.vercel.app and press Settings → Make available offline, so the stand keeps working if the Wi-Fi drops.

2 Print the templates

Press Open day at the top. Choose the template: the keyring tag, medium, with a printed hole is the classic. Words for everyone on the back, such as OPEN DAY 2026, are optional.
Leave Where does your printer touch the bed… on The middle of the bed for a CR-6. That spot is kept clear, so the designs can be printed later even if the printer has been switched off.
Choose how many. Up to 94 keyring tags fit; each takes about 20 minutes including ironing its top, so 30 take roughly 10 hours. The G-code dialog shows the time for your plate.
Press Make template G-code…, then Make G-code, watch it in the player and download it. Copy it to the SD card and print it.
Leave the templates on the bed and don't move the bed. Press Save plan to keep a copy of the plan on a USB stick.

Use Printurtle's G-code for the templates: the designs are sliced on exactly the same layers, so their first layer lands on the templates' top.

3 Visitors design their keyring

In Open day, press Design the next keyring (or tick Open day mode). From then on Quick make is a full-screen page that designs onto the templates. Open printurtle.vercel.app/?openday for the stand page, or ?kiosk for Quick make with bigger buttons. Use Back to full editor when you need the ordinary workspace. Untick the box after the event.
The visitor picks what goes on top (a name, an icon, pixel art, binary…), chooses its colour and types their name. The 3D view shows it on the template.
Add to the open day plate puts the design on the next template and tells them its number. Press Next person.

Designs are collected in the browser that took them. Collect on one laptop, or press Save plan there and Load plan on the laptop connected to the printer.

4 Print the designs over the templates

Open Open day. Under Print the designs over the templates, choose Designs not printed yet and press Make G-code for the designs….
Press Make G-code. The player shows the designs being drawn on the templates. Download the file and copy it to the SD card.
Load the filament for the designs (white shows up well on a coloured template) and start the file. It heats up, homes at the clear spot in the middle, loads the bed mesh and prints only the designs.
Press Mark these as printed. As more visitors design, repeat this for the next batch.

5 Hand them out

Let the bed cool a little, then lift the finished keyrings off. Each template's number is on the plate view in Open day, so you know whose is whose.
Thread a 25 mm split ring through the hole.
Any file can be made again later: in the G-code dialog, Copy a download link keeps a link with the design and every setting inside it. It works on any computer, whatever happens to a server.

Problems and fixes

The nozzle moves but no plastic comes out (not even the priming line): Every file starts by pushing filament slowly just above the priming line, with Priming – plastic should come out now on the screen. If nothing appears there, stop the print: the filament is chewed or the hot end is blocked, and no file will print until that is cleared. Heat the nozzle to 210 °C, press the extruder arm and pull the filament out, cut it off above any chewed or flattened part, check the white tube is pushed fully into the hot end and its clip is in, then feed the filament back until plastic flows from the nozzle. If it will not flow by hand, do a cold pull or change the nozzle. Cancelled prints leave the filament in an unknown state, which is why the priming is slow.
“Print 2 starts lower than the top of an earlier print” or “can't be made as a separate file”: Something went wrong with an older file that had a raised screw-eyelet pad. Current Printurtle eyelets are flush with the tag, including Open day. If a separate-file print still fails, use one file with a pause, or the printed hole. For no-tools nights, prefer the printed hole over screw eyelets.
The designs don't stick to the templates: Keep the bed warm (60–62 °C), don't touch the templates' tops, and check the first layer of the designs goes down. A little more first-layer squish helps: lower the first layer speed in Settings.
The designs are in the wrong place: The templates or the bed moved, or the templates were printed with another slicer or different layer heights. Print the templates with Printurtle and don't move them.
The printer was switched off between the two prints: Fine, as long as The middle of the bed was chosen when laying out the plate: the designs file homes at the clear spot. If you chose Nowhere, keep the printer on.
The printer didn't pause for the second colour: Your firmware may not support M600. Choose M0 (or PAUSE on Klipper) as the pause command in Settings.

Python

3D design

Open day keyrings

1 The template

2 How many on the plate

3 Print the templates

4 Visitors' designs

5 Print the designs over the templates