Get from model to print.

Your first print

1. Open the Print tab. Tap the + button, then Open a model file. Choose an STL, 3MF, or STEP file.
2. Check the part on the build plate. Use the plate tools to move, rotate, duplicate, or lay it flat if needed.
3. In Print settings, tap the printer row that says Tap to change printer and choose the correct model. Check the Material row too.
4. Tap Slice. When the result says Ready to print, review the layer count, estimated time, filament amount, and Preview layers.
5. For a connected printer, tap Print or Send to Printer and follow the connection steps. Otherwise tap Save to USB drive or SD card and transfer the G-code to your printer.

If you do not have a model file, tap + and choose Design a part to start from a template or a traced outline.

Connect a printer

Keep your phone or computer and printer on the same local network. In the Printers tab, use Find printers on Wi-Fi or Add by IP address. Some connections are set up the first time you send a print instead.

Elegoo Centauri Carbon 2

1. Open Printers and tap Find printers on Wi-Fi. Tap the Centauri Carbon 2 when it appears.
2. If it is not found, tap Add by IP address. Enter the address shown under Settings → Network.
3. Enter the printer's access code. If the printer uses its default code, leave the field empty. Tap Add.

Elegoo Centauri Carbon (first generation)

1. Open Printers and tap Find printers on Wi-Fi. Select the Centauri Carbon when it appears.
2. If search misses it, tap Add by IP address and enter the printer's network address.
3. This model does not ask WrenSlicer for an access code. Leave Access code empty and tap Add.

Klipper with Moonraker

1. In Print settings, tap Tap to change printer and choose a printer profile with a Moonraker connection.
2. Slice the model and tap Send to Printer. Enter the IP address or .local address you use for Mainsail or Fluidd. Add the Moonraker port, commonly :7125, when your setup requires it.
3. Enter an API key (only if you set one up). Turn on Start printing right away if you want the printer to begin after upload.
4. Tap Print to start now, or turn the switch off and tap Send to Printer to upload without starting.

PrusaLink

1. Choose a printer profile that uses PrusaLink, then slice and tap Send to Printer.
2. Enter the printer's IP address or .local name in Address.
3. Enter the password shown on the printer under Settings → Network → PrusaLink. Set Start printing right away as you prefer, then tap Print or Send to Printer.

OctoPrint

1. Choose a printer profile that uses OctoPrint, then slice and tap Send to Printer.
2. Enter your OctoPrint address. In OctoPrint, open Settings → Application Keys and create or copy an API key.
3. Enter the API key in WrenSlicer. Choose whether to start printing right away, then tap Print or Send to Printer.

Bambu Lab

1. On the printer, open its network settings. Turn on LAN Only Mode, then Developer Mode. The app shows model-specific directions in the setup screen.
2. In Printers, tap Add printer (the + button), then A Bambu Lab printer. Search the network or enter the printer details.
3. Enter the printer's IP address and 8-character access code from its network screen. The serial number is optional; if you found the printer on Wi-Fi, WrenSlicer fills it in for you. Tap Add Printer.
4. A1 and P1 printers also need a microSD card inserted. While LAN Only Mode is on, Bambu Handy cannot reach the printer; switch LAN Only Mode off to return to Bambu's cloud.

Use an IP address or a .local name for local network connections. Names ending in .lan are not accepted by the current iOS connection screen. If a printer profile only offers file export, save G-code and use the printer maker's workflow.

Save to a USB drive or SD card

iPhone or iPad

1. Connect the drive or card reader. Use a USB-C adapter on USB-C devices or a Lightning adapter on Lightning devices.
2. After slicing, tap Save to USB drive or SD card. In the Files save sheet, choose the drive, pick a folder, and tap Save.
3. You can also tap Save or share, choose Save to Files, select the drive, and tap Save.
4. Eject the drive safely, then connect it to the printer and open the saved .gcode file.

Android

1. After slicing, tap Save to USB drive / SD card or Save G-code….
2. In the Android save dialog, choose the USB drive or SD card, select a folder, and tap Save.
3. Safely eject the drive, connect it to the printer, and select the G-code file.

Photo to Part

1. Open the Build tab, tap Design a part, then choose Photo to part (AI).
2. Tap Take Photo or Choose Photo. A straight-on photo in good light works best. Include an object of known size if you can.
3. In What is it, and what should it do?, describe the part and its job. Add a known measurement if you have one.
4. Tap Draft the part. Answer the size questions and tap Use these answers, or choose Skip, and adjust the sizes myself.
5. Review and edit every dimension and feature. Tap Use This Part to send the model to Print.

This AI feature needs an internet connection and may be unavailable in some test builds. Check the model before printing. Trace from a photo and part templates work on the device without AI.

Trace a drawing

1. Draw a dark, closed outline. Draw each hole as a closed circle inside the outline. Keep the paper corners visible.
2. Place the paper on a darker surface and photograph it from straight above. Keep all four corners of the sheet in frame.
3. In WrenSlicer, open the Build tab, tap Design a part, then choose Trace from a photo.
4. Choose the paper size under Paper and set the part's Thickness in millimetres.
5. Tap Take Photo or Choose Photo. Wait for the outline preview, check the traced edge and holes, then tap Use this outline.
6. Adjust the dimensions and features in the designer, then tap Use This Part to send it to Print.

If tracing fails, retake the picture with every paper corner visible, less glare, stronger contrast, and the camera directly overhead.

Materials and custom materials

1. On the Print tab, find Material in Print settings and tap the current filament.
2. Search by material or brand, or browse Favourites, Recent, and material families. Tap a material to use it. Compatibility notes are checked against the selected printer.
3. To make your own, tap the plus button labeled Add or import materials, then choose New from [material name]. This starts with a copy of the selected material.
4. Set Name, optional Brand, Type, and colour. Update temperatures and other values from the spool label or manufacturer guidance. The More section contains flow, retraction, enclosure, drying, and notes.
5. Tap Save, then choose the new material under My materials. Swipe its row to edit or delete it.
6. To share or move custom materials, use the plus button and choose Share my materials or Import… with a JSON file.

Built-in values are typical starting points. If your spool label differs, use the spool's values. Custom materials are stored on this device; export a copy before moving to another device.

Will it hold?

1. Add a part to the plate and select it. From the Print tab's assistant menu, tap Will it hold?.
2. Enter the load and choose kg or lb.
3. Choose the force direction: Pull up, Pull sideways, or Press down. Directions are based on how the part sits on the plate.
4. Choose the material. WrenSlicer estimates automatically on the device.
5. Read the safety factor, likely failure mode, weakest layer, and suggested changes. Rotate the part on the plate and check again if it could be loaded another way.

This is a rough engineering estimate, not a certification or a guarantee of safety. Real strength depends on the printer, material, settings, orientation, and use. The optional Explain & suggest fixes AI action needs an internet connection.

Calibration tests

The iOS source includes a Calibrate screen with these controls, but the current navigation does not link to it. If you cannot find Calibrate in your build, the screen has not been exposed yet.

Fit test

1. Choose Fit test and tap Add the fit test to the plate.
2. Print the bar and peg with your normal settings. Hole 1 is the tightest; hole 7 is the loosest.
3. Push the peg into each hole. Set the tightest hole it enters by hand and the first hole it drops into freely.
4. Tap Use these fits. The measured clearances are then used by designs that ask for tight or loose fits.

Temperature tower

1. Select the filament you want to tune under Material in Print settings.
2. Choose Temperature tower, then tap Add the tower to the plate. Print the tower by itself.
3. Compare the blocks and tap Use beside the temperature that prints cleanly. Temperature steps remain on until turned off.
4. When you finish the tower, return to Calibrate and tap Turn temperature steps off.

Retraction test

1. Choose Retraction test and select a retraction length.
2. Tap Add the test with [value], print it, and inspect the gap between the two towers.
3. Clean gap with no strings: keep that value. Fine strings: try the next value up. Gaps, blobs, or clicking: go down a step.
4. If every value strings, dry the filament or lower nozzle temperature; retraction cannot fix wet filament.

Troubleshooting

1. On the Print tab, open the assistant menu and tap Something went wrong with my print.
2. Choose the symptom. Read What it looks like and Why it happens, then follow Try these, one at a time.
3. Tap the information icon beside a setting to read what it does. Change one thing, print a small test, and compare.

Thin strings or hairs

1. Lower nozzle temperature by 5 °C at a time.
2. Increase retraction a little; the app's guide suggests 0.2 mm steps for most printers.
3. Dry damp filament, especially PETG or TPU. Turn Z-hop off if it is on.

Corners lifting (warping)

1. Add a brim and raise bed temperature by 5 °C.
2. Clean the bed with warm water and dish soap, or rubbing alcohol, then avoid touching the print area.
3. For ABS or ASA, reduce fan and close the enclosure. Try a raft only if other changes do not help.

Layer shift

1. Stop the print if the nozzle is hitting the part. Check for a collision or a part that lifted from the bed.
2. With the printer off, inspect belts and pulleys using the printer maker's instructions. Do not force the axes.
3. Try a smaller test at lower speed. The current built-in Fix a print list does not yet include a layer-shift topic.

Gaps, thin walls, or under-extrusion

1. Check that filament feeds freely and is not tangled or ground down.
2. Print slower and raise nozzle temperature by 5 °C if the hot end is not melting plastic fast enough.
3. Clean or replace a partly clogged nozzle according to the printer maker's instructions.

Print will not stick to the bed

1. Clean the bed and avoid touching the print area.
2. Run bed levelling or auto-levelling, then slow the first layer.
3. Raise bed temperature by 5 °C, make the first layer slightly thicker or wider, or add a brim for small feet.

For mechanical problems, follow the printer maker's instructions. If a fix makes the print worse, restore the previous setting before trying the next one.