Digital fabrication technologies, such as 3D printers, are receiving more and more attention, not only from professionals but also from hobbyists. However, even though people have easier access to these devices, 3D printers remain a black box for many users. To support the appropriation of 3D printers, this demonstration presents a system which extends a physical printer to include virtual components using augmented reality (AR). With these components, we try to explain how the printer works and allow the user to operate the printer through an AR application. We extend existing software with a custom solution to create a unique user interface and user experience. Our user interface provides a new way of inspecting models in AR before they are printed.