For legal reasons, we are not allowed to discuss safety concerns except in the Beyond the Manual section, but killing a print by lifting the lid is covered by the manual, so I’m going to put some pictures here to show people what exactly is involved. New users instinctively think that lifting the lid is going to feed the flames, but it doesn’t if you do it right.
Note: It’s not unusual, depending on what and where you are cutting, to see the equivalent of a candle flame underneath the material where the laser is piercing the material, and you can see it at the top as well. The air assist usually keeps that knocked back on the surface, but if you are cutting too close to an edge, or near previous cuts that allow air to get in underneath the material, you can see it flame up up a little on top. That isn’t going to hurt anything, and the flame should go out when the beam moves out of the area.
What you don’t want to see is a flame that continues burning after the laser beam has moved on away from a spot. That’s a sign of ignition - stop the cut by lifting the lid about half an inch to break the magnetic seal.
After you break the seal you can lower the lid back down.
Don’t try to cancel the print from the computer - after the instructions have been sent to the machine from the cloud, it will finish the cut.
That’s all it takes, I can do it with one finger in a fraction of a second. Less time than it takes to find and press a button. Granted though, it’s not nearly as fun and exciting as a panic button.
I would highly recommend that new users practice killing a print a few times to see what happens. After the magnetic seal is disrupted at the front of the machine, the head quits firing and returns to the home position. Don’t wait until you need it to get familiar with the process.