Photon Mono M7 Pro: the print does not stick to the build plate or leveling fails (code 303)

Symptom

On the Photon Mono M7 Pro the print cures stuck to the ACF film of the resin vat instead of the build plate, only the base sticks, or the printer reports «Leveling failed, please refer to leveling tutorial (CODE: 303)».

Likely causes, from most to least likely

1. The build plate is dirty or has cured residue.
2. Exposure: the LCD does not display the image properly or the exposure is too short for the resin.
3. Resin parameters: with another brand's resin, the default settings may not work.
4. Cold room: below 20 °C the resin flows less well.
5. Leveling: the build plate does not press the paper equally on both sides, or the force sensor needs calibrating.
6. The build plate has been dropped, or the build plate or the LCD has been replaced: it must be leveled manually again.

Checks to tell which one it is

• Look at where the cured resin ends up: on the film with nothing on the build plate, or only the base stuck to the build plate.
• Run the exposure test in step 2: the image on the LCD must match the one on the control screen.
• Run the leveling test in step 5: the paper must be hard to pull out on both sides.

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 resin vat and the build plate

   Wearing gloves and safety glasses, with ventilation, clean the resin vat by removing cured residue and clean the build plate with alcohol.

   Check: No residue is left on the build plate or in the vat.

   If that does not fix it: Check the exposure (next step).

2. Exposure test

   Remove the resin vat and the build plate, place a sheet of A4 paper on the LCD, go to «Tools» → «Exposure Test», select the first pattern and tap «Exposure». Do not look directly at the exposed image: it can harm your eyes.

   Check: The image on the paper matches the one on the control screen.

   If that does not fix it: If it does not match, record a video and contact the shop or Anycubic support.

3. Test with official resin and test files

   With another brand's resin, try Anycubic resin: if it prints well, ask your supplier for the settings or use the «R_E_R_F» test file. If it also fails with official resin, print the «TEST Default Resin Fast» test file from the USB drive. If nothing appears on the build plate, raise the bottom layer exposure to 80 s; if only the base sticks, raise the normal exposure.

   Check: The test model forms on the build plate.

   If that does not fix it: Check the temperature (next step).

4. Heat the resin when it is cold

   Below 20 °C, go to «Tools» → «Advanced» → «Intelligent Resin Vat Heating», choose the temperature and turn on automatic heating: the vat heats up before printing. After heating for a long time the vat can be very hot in places: do not touch it directly when the print finishes.

   Check: The vat reaches the temperature and the print sticks.

   If that does not fix it: Check the leveling (next step).

5. Leveling test

   Remove the resin vat and clean the build plate. Place a leveling sheet or A4 paper at the top left of the LCD and go to «Tools» → «Move Z-axis» → «Leveling Test». The build plate goes down, rises a little and slowly descends again: do not touch the paper until it stops. Then pull the paper and repeat on the right side.

   Check: The paper is hard to pull out on both sides.

   If that does not fix it: If it slides out easily on either side, level manually (next step).

6. Manual leveling (code 303)

   Loosen the knob and remove the build plate; loosen its four screws with the 4 mm Allen key and refit it, tightening the knob. With the paper on the LCD, use «Tools» → «Move Z» → «Z-axis zero point», lower it 1 mm once and then in 0.1 mm steps until the build plate barely moves when touched. Hold it down by hand, tighten the four screws diagonally and finish with «Leveling test».

   Check: The paper offers strong resistance when pulled.

   If that does not fix it: If it slides out easily, loosen the four screws and repeat the adjustment.

7. Calibrate the force sensor

   In «Settings» → «System» → «About» → «Detailed information», tap the device name about ten times in a row and open «Mechanical Calibration». Remove the clean build plate and tap «Removed»; fit it and tap «Installed»; tap «OK» when done. Anycubic recommends running the calibration several times so the data is reliable.

   Check: The calibration completes and the print sticks to the build plate.

   If that does not fix it: If the force sensor cable is loose or code 313 appears, contact Anycubic support.

Prevention

• Clean the build plate with alcohol after each use.
• Level manually again if the build plate is dropped, if you replace the build plate or the LCD, or if the print stays in the vat.
• Below 20 °C, print with vat heating turned on.

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Printers it applies to

Anycubic Photon Mono M7 Pro.

Official sources

This guide summarises the official documentation linked here:

• Photon Mono M7 Pro - Printing with models not sticking to the print bed troubleshooting · Anycubic
• Leveling failed, please refer to leveling tutorial (CODE 303) - Photon Mono M7 Pro · Anycubic
• Photon Mono M7 Series - Mechanical Calibration Guide · Anycubic
• Photon Mono M7 Pro - Maintenance Recommendations · Anycubic
• M7 Pro FAQ · Anycubic