This is a space coffee mug concep to use in micro gravity only. As you understand it was never tested under micro gravity. The theorie is the coffee should take the shape of the inside of the mug. The piston is free and is only there to finish the shaping of the liquid. As you suck the coffee through the beek, the liquid should move toward the beek and the piston should folow. since there is a gap between the piston and the wall of the mug there might be a remnant of coffe left on the wall. We would know only if we try it in micro gravity. I designed it as close as possible to a real standard mug to give  you a good feeling. I printed it on a Dremel 3D printer using Simplify3D as a slicer. the walls thickness are two layers, the top and bottom of the object are 3 layers. I used 15 % infil with rectilinear grid. Suport is 30% Thank you. Jean-Claude bouchard