PROCEDURE FOR MEASURING PLOTTENESS OF SHEET MATERIAL Russian patent published in 2004 - IPC

FIELD: measurement technology. SUBSTANCE: procedure for measuring plotteness of sheet material presents measurement of width of distribution of light projection on surface of sheet material in the form of concentric rings placed one inside another, obtained by means of two light sources as minimum and displaced one relative another in vertical direction. Plotteness of sheet material is established as difference in heights of individual sections of sheet material found by following expression H_i = L₁-L₀(X_0i/X_1i-1), where L₀ is distance from reference plane to light source 1, mm; L₁ is distance from reference plane to light source 2, mm; X_0i is width of i-th projection of ray on surface of sheet material from light source 1, pixels; X_1i is width of i-th projection of ray on surface of sheet material from light source 2, pixels; i is number of individual projection of ray on surface of sheet material. EFFECT: enhanced accuracy and reliability of measurement of sheet material, raised quality of products. 3 dwg