PFB Designer is inspired by SFB Designer- our web-based analysis and manufacturing tool for spherical four-bar mechanisms. PFB Designer was created to address the challenges of detailed design, part layout, and dynamic analyses of planar four-bar mechanisms. PFB Designer provides designers a free, web-based, tool to layout the parts and view the assembled mechanism. PFB Designer lets the user specify the dimensions of a planar four-bar mechanism and then Pro|E part and assembly drawings are automatically generated. These drawings can be downloaded as Pro|E part and assembly files or in STEP, dxf, iges, and other formats for use with other CAD/CAM software packages. These files can be used to: visualize the three-dimensional assembly of the mechanism(ASM, JPG or TIF), perform static and dynamic anlyses(ASM), make a rapid-prototype (STL or STEP), or finally to manufacture the mechanism using a CNC machine tool (ASM, STL or STEP). Moreover, tiff and jpg images of the assembled mechanism can be generated as well (see below). PFB Designer facilitates the design, visualization, prototyping and manufacture of planar four-bar mechanisms. PFB Designer lays out the mechanism's links using feet at either end. The feet are designed to facilitate the accurate placement and orientation of the axes and the use of bearings. The result is a compact mechanism that conserves material and has been layed out to facilitate precise link lengths and accurate axes placement.