Saturn 4 Ultra 16K: the print stays in the resin tank or comes off the build plate

Symptom

On the Saturn 4 Ultra 16K the base of the print does not stick to the build plate, the print comes off and falls into the tank at some height or in the centre of the build plate, or the self-test reports «Foreign matter detected, please troubleshoot», for example because of residue from an earlier failure.

Likely causes, from most to least likely

1. Resin too viscous: it flows back badly under the print and does not cure fully.
2. Leveling: too much gap between the build plate and the LCD, or a build plate lacking accuracy.
3. The build plate is dirty, with cured resin or burrs, or not fitted and locked properly.
4. The LCD is loose or badly fitted; or the exposure is abnormal, the LCD cable makes poor contact or the firmware is not the right one.
5. The film is whitened, scratched, damaged or aged.
6. Cured residue in the tank after a failure, or strong light (sun or UV) curing the resin in the tank.

Checks to tell which one it is

• If nothing has cured on either the build plate or in the tank, check the exposure first: in «Tool» → «Exposure» → «ELEGOO» the LCD must display the Elegoo logo properly.
• Note where it fails: the whole base, at some height or only in the centre of the build plate.

Before you start

Uncured resin irritates skin and eyes: wear nitrile gloves and safety glasses, ventilate the room and do not look at the UV light. Before taking anything apart or cleaning it, switch the printer off and unplug it, unless a step says otherwise. If in any doubt, stop and ask a professional.

Step-by-step fix

1. Clean the tank and the build plate

   Wearing gloves and safety glasses, with ventilation, remove the failed print and cured residue from the tank with a plastic scraper, leave the film and the bottom clean, and clean cured resin and burrs off the build plate.

   Check: Nothing is left in the tank or on the build plate.

   If that does not fix it: Warm the resin (next step).

2. Warm the resin

   The optimal resin temperature is 25 °C. Below that, turn on tank heating beforehand or warm the bottle for about 10 minutes in water at about 60 °C so the resin is less viscous.

   Check: The base sticks to the build plate.

   If that does not fix it: Adjust the slicing settings (next step).

3. Adjust the slicing settings

   Raise the normal layer exposure by 1 to 3 s and the rest time after release by 2 to 3 s. On bottom-up LCD resin printers like this one, also raise the lift distance by 2 to 3 mm.

   Check: The print no longer comes off mid-print.

   If that does not fix it: Check the film and the LCD (next step).

4. Check the film and the LCD

   If it fails in the centre of the build plate, check whether the film is whitened, scratched or damaged and replace it. Check that the LCD screws are not loose and that there is no gap or misalignment between the LCD and the frame; if there is, refit it as in Elegoo's official video.

   Check: Prints also stick in the centre.

   If that does not fix it: Check the build plate and the sensors (next step).

5. Build plate and sensors (Foreign matter detected)

   Place the printer on a firm, level surface away from vibrating appliances, and do not expose the tank to sunlight or strong UV light. Remove and refit the build plate so it is properly locked, and tighten its screws if they are loose. Avoid very viscous resins. If the message persists, check the cable between the mechanical sensor and its adapter board.

   Check: The self-test passes without the message.

   If that does not fix it: Prepare the information for Elegoo (next step).

6. Firmware and information for Elegoo

   Check that the firmware is the right version. If it persists, send Elegoo support photos of the failed print, the sliced file, a photo of the LCD exposure, the resin label, the firmware version and the serial number. For «Foreign matter detected», print Elegoo's Exporting.gcode file from the root of a USB drive, without renaming it, and send the 100MachineParams.gcode it creates, with the resin type and its viscosity.

   Check: Support tells you what to adjust or which part to replace.

   If that does not fix it: Follow their instructions.

Prevention

• Clean the tank after every failed print.
• Print with the resin at about 25 °C.
• Avoid very viscous resins and strong light on the tank.

Still not fixed?

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Printers it applies to

Elegoo Saturn 4 Ultra 16K.

Official sources

This guide summarises the official documentation linked here:

• Model Base Not Adhering to Build Plate / Model Detaching During Printing · Elegoo
• Model Detachment at Center of Build Plate · Elegoo
• Self Test: Foreign Matter Detected (Saturn 4 Ultra 16K) · Elegoo
• LCD Screen Replacement A0S0V1 (Saturn 4 Ultra 16K) · Elegoo