In this paper, we propose a method to create 3D inflatable objects by laminating plastic layers. AccordionFab is a fabrication method in which the user can prototype multi-layered inflatable structures rapidly with a common laser cutter. Our key finding is that it is possible to selectively weld the two uppermost plastic sheets out of the stacked sheets by defocusing the laser and inserting the heat-resistant paper below the desired welding layer. As the contribution of our research, we investigated the optimal distance between the lens and the workpiece for cutting and welding and developed an attachment which supports welding process. Next, we developed a mechanism of changing the thickness and bending angle of multi-layered objects and created a simulation software. Using these techniques, the user can create various prototypes such as personal furniture that fits user's body and packing containers that fit the contents.