a method and an apparatus for sheet embossing are disclosed that imparts the same strain on each side of the sheet independent of pattern pick - up . by balancing the plastic deformation at each surface the stresses in the formed material are well controlled and , in fact , greatly improve the sheet flatness , material internal stress , surface corrosion and other properties associated with this balanced process . controlled sheet shape is important to the industrial handling of material on conveyers , spoolers , stackers and other transport devices . current industrial practice often mandates the use of sheet levelers that reform the surface through a series of rollers that plastically force the material flat , however , not at controlled stress . with the invention , expensive levelers are often not necessary and , as such , the overall process becomes more efficient .