A flatbed plotter is a device that uses pens to draw graphics and pictures, instead of printing heads, nozzles, and ink cartridges used in typical printers. Used mostly to produce architectural and engineering drawings, the plotter has a flat vacuum bed or table and a moving arm to accommodate pens. A primary pen is also included, in addition to a pen cartridge and spare pens. Flatbed plotters use vector graphics to draw and can be up to 50 feet (15.24 meters) across. A special roll mechanism feeds paper into the machine, while another rolls up the paper after it is drawn on.
Motion is controlled by a robotic arm, or several of them to accommodate more sophisticated drawings. The paper can be held down by clamps, but is often secured to the surface by an electrostatic charge generated by the system. On large plotters, a vacuum system is used, which is turned on after the paper is placed on top of the machine. The beam sits above the table, on which a pen moves along the length of, and the beam moves along the flatbed plotter length, allowing for X- and Y-axis motion.
The flatbed pen plotter is not designed for printing text, but an inkjet head can be incorporated if text or annotations are required on the printout. It is also possible to modify a machine into a flatbed cutting plotter by attaching routing and milling tools to the arm. Materials from cardboard to metal can be cut using this configuration.
Computer software is used to control a flatbed plotter. Computer aided design (CAD) software can help design what needs to be drawn on the plotter, using a computer. The processor inside most flatbed plotters is programmed using Hewlett-Packard Graphics Language (HPGL), while Beginner’s All-Purpose Symbolic Instruction Code (BASIC) or IBM Mathematical Formula Translating System (FORTRAN) languages are used to program and operate older models. Most machines have Read Only Memory (ROM) that allows the motions of the pen and arm to be programmed by the user.
The computer files that hold the data to be plotted are called plotfiles. These files are read by a plotter management program, from which the settings of a flatbed plotter can be adjusted. Whatever the format of the file created by the computer, the program converts it into a format known by the plotter. A parallel or serial cable is connected from the computer to the flatbed plotter, and data can even be sent via email from CAD systems to plotters in a different location.