3D printing from an Android phone or tablet

Android is well suited to this, with one gap

An Android phone or tablet handles files like a small computer: downloads go to a Downloads folder you can browse, and most models read a USB-C card reader or stick. The gap is the slicer. OrcaSlicer, PrusaSlicer, Cura and Bambu Studio are desktop programs for Windows, macOS and Linux, with no Android version. The Play Store has a few third-party slicing apps; if you try one, check that it has a profile for your exact printer.

The route below uses a slicer in the browser: SpeakCAD's online slicer runs the unmodified OrcaSlicer on a server with your printer's own profile, and Chrome shows the model and the settings.

Step 1: find the model

The slicer takes an STL or 3MF of up to 50 MB.

• Downloaded in Chrome: it is in Downloads, shown in the Files app (Files by Google or the phone maker's file manager) and in the notification shade when the download finishes.
• Sent to you: save the attachment from the messaging or e-mail app; most save to Downloads.
• In Google Drive: the file picker lists Drive, so there is no need to download it first.

Step 2: slice it in Chrome

1. Open the online slicer in Chrome and sign in, or create an account (free, no card).
2. Tap Choose a file. Android opens its file picker, with Recent files, Downloads, Drive and any USB drive plugged in. The layout depends on the Android version and the phone's maker, and some phones first ask whether to use the camera or files.
3. Check the model in 3D: the right part, a plausible size, the flat face down.
4. Pick your printer's Brand, Model and Nozzle among 380+ printers from 60+ brands. It is saved on your account.
5. Choose the Print profile (layer height) and the Material; leave Supports and Adhesion on Auto for a first print.
6. Tap Slice and download.

The page reports the print time, the filament in grams and meters, the layer count and any supports. Change a setting and slice again to compare: re-slicing the same file within 10 minutes spends nothing. On a tablet the settings sit beside the 3D view, which makes this comfortable on the workbench.

Step 3: check the download

Chrome saves the G-code to Downloads. Most printers get a .gcode file; Bambu Lab printers get a .gcode.3mf. Two things can go wrong:

• A warning about the file type. Chrome may ask whether to keep a file type it does not recognise. G-code is a text file of printer commands; keep it.
• A changed name. A second download of the same name gets "(1)" appended. Rename it in the Files app so the printer's screen shows something readable, and keep the .gcode.3mf ending for Bambu Lab.

Step 4: get it to the printer

Over Wi-Fi, through the printer's web page

Klipper printers run Mainsail or Fluidd; OctoPrint runs on a small computer, often a Raspberry Pi, connected to the printer; networked Prusa printers have PrusaLink. With the phone on the same Wi-Fi, type the printer's IP address into Chrome, tap upload, choose the file from Downloads and start the print. Adding the page to the home screen makes the next print one tap away.

SD card or USB stick, through USB-C

Most Android phones and tablets with USB-C can read a USB-C card reader or stick (the feature is called USB OTG); a few phones ask you to turn it on in the settings first. The card appears in the Files app. Copy the G-code from Downloads to it, use the eject or unmount option in the Files app or the notification, then put the card in the printer.

The printer maker's app

Some printer makers' apps open a file shared from the Files app. For Bambu Lab printers, Bambu Handy monitors prints and starts them; whether it can send a .gcode.3mf from your phone's storage depends on the app version, so check it once. The microSD card works on any Bambu Lab printer with a card slot.

When something goes wrong

• The file does not show on the printer. Check the ending (.gcode, or .gcode.3mf for Bambu Lab), and that the card uses a format the printer reads; many printers expect FAT32.
• The card does not appear on the phone. Try the reader in another port or device, check the USB OTG setting on phones that have one, and use a reader rather than a hub with several ports.
• The printer's web page does not load. The phone must be on the same Wi-Fi as the printer, not on mobile data or a guest network.
• The model looks tiny. An STL has no unit; a model exported in inches arrives 25.4 times too small. Export it again in millimetres where it came from.

Phones, tablets and Chromebooks

The same steps work on an Android tablet. A Chromebook that runs Android apps is still better served by the slicer in Chrome, with the Files app and its card slot; slicer for Chromebook covers that case.

What the browser route will not do

The online slicer covers single-material prints with the settings that shape a part. It does not do colour painting, modifiers, variable layer height, custom start G-code or a toolpath preview; for those, a desktop slicer on a computer remains the tool. Online slicer vs desktop slicer goes through the trade-offs.

What it costs

The online slicer gives every account 1 free slice, its first (a free account, no card). After that, a slice uses one slice from a Slicer pack (20 slices for $3, once, never expire) or 5 credits, and slicing is included in Pro and Unlimited. Re-slicing the same file with other settings within 10 minutes is free. To estimate the time, filament and cost of a print before slicing, the print time and cost calculator needs no account.

The short version

Slice in Chrome, then upload the G-code on the printer's web page or copy it to a card through USB-C. Slicer for Android keeps the steps on one page, and the online slicer takes the file you have.