Flashforge AD1 User Manual page 17

Load the filament into the spool holder on the left and right side respectively, pass
the filament holes through the left and right filament detecting switches
respectively, and then thread into the filament feeding motor until the filament
reaches the nozzle.
Note: Be sure to put the left and right filament into the nozzle, or else there
is a risk of blocking or abnormal extrusion.
1.4 设备设置操作
1.4.2 Installing Filament
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