120
Moderate
Formlabs · Professional Resin 3D Printers
Build Platform Not Detected - Platform Sensor Not Triggered
Quick Answer
Error code 120 on your Formlabs Professional Resin 3D Printers means: Build Platform Not Detected - Platform Sensor Not Triggered. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Remove and reinsert the build platform, ensuring it slides fully into the carrier and the locking lever clicks into place
2
Inspect the build platform mounting surfaces for debris, cured resin, or damage that prevents proper seating
3
Check the locking lever mechanism for smooth operation
4
Clean the platform detection sensor area with isopropyl alcohol
5
If using the Form 4 Build Platform 2, ensure it is the correct version for your printer
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Replacement build platform (model-specific: standard or Build Platform 2)
Platform detection sensor (if sensor replacement is needed, contact Formlabs)
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