There is provided an apparatus for molding a thermoplastic material into a homogenous sample body having a predetermined shape, the apparatus comprising: (a) a main body (110) comprising a first opening (112), a second opening and a hollow bore (116) connecting the first opening (112) with the second opening, the hollow bore (116) being adapted to receive a separation foil shaped to cover at least a part of the hollow bore surface; (b) a piston (120) adapted to fit moveably into the hollow bore (116) containing the separation foil; (c) a base plate (130) comprising a protrusion, wherein the base plate (130) is adapted to be inserted into the first opening (112) in such a manner that the protrusion extends into a part of the hollow bore (116) containing the separation foil, and wherein the base plate (130) is adapted to transfer heat from a heating unit to a thermoplastic material (150) resting on the protrusion (132); (d) a vacuum connector (142) adapted to be connected to a vacuum source; (e) a lid (140) adapted to fit moveably into the second opening and adapted to apply a force to the piston (120) when the vacuum connector (142) is connected to the vacuum source such that the piston (120) applies a compressing force to the thermoplastic material (150) resting on the protrusion. There are further provided a method and a system for molding a thermoplastic material into a homogenous sample body having a predetermined shape.