Below, you will find photos diagramming which screws belong to which parts of the machine. All screws shown are 2mm hex. The photos are of an Ultimaker 2. If you have an Ultimaker 2 Extended, you will have an additional frame screw vertically on the side panels. The Ultimaker 2+ and Ultimaker 2 Extended+ panels are the same with the exception of the feeder. Do not remove any of the screws labeled "Frame Screws." All of your printer's motors and electronics can be accessed by removing the covers on the machine; the frame panels themselves never have to be removed.
THE BACK PANEL (feeder for Ultimaker 2)
THE Ultimaker 2+ FEEDER (other screws on back panel the same)
THE BOTTOM PANEL
THE LEFT PANEL
THE RIGHT PANEL
THE TOP PANEL