A vacuum mechanism for flattening bowed panel samples includes a support structure with coplanar support elements and a fixture with a movable component actuated by a vacuum source. The movable component has a top surface disposed above the support elements when no vacuum is applied and is capable of being drawn to a substantially coplanar position with the support elements when actuated by the vacuum source. The top surface is fluidly connected to the vacuum source and adapted to adhere to the overlaying surface of the sample when vacuum is applied, thereby flattening the sample when the movable component is drawn in by the same vacuum source.