Heat Bed

When the metal plate is removed, it exposes the heating surface, called the Heat Bed, shown in the next picture.

The heat bed is a flat platform that the metal plate sits on. It is called a heatbed because it has heating elements that heat up the metal plate when its attached so that the plastic extruded from the nozzle will stick to the metal. As the heat bed warns, you should never print on this surface when the metal plate is not in place. The metal plate is attracted to several magnets mounted below the heating surface. The magnets are mounted on the bottom of the heat bed, so you can’t actually see them from above. These magnets are strong, so it is very important that when replacing the metal plate, once it is lined up with the screws on the upper edge, you should lower it slowly until it gently snaps into place.