PRODUCTION OF MASK FOR PRINTING PRINTED CIRCUIT BOARD

摘要

PURPOSE:To form the mask having slit holes which have smooth inside surfaces and high accuracy by forming the slit holes on a thin metallic sheet to the sizes slightly smaller by 0.01 to 0.02mm than the final finish sizes by electric discharge machining using a comb-shaped electrode for electric discharge machining and passing a chemical polishing liquid into the slit holes thereby smoothing the inside surfaces of the slit holes and simultaneously finishing the holes to the required size. CONSTITUTION:The slit holes 3 having 1.38mm vertical width and 0.13mm horizontal width slightly smaller than the final finish sizes 1.4mm vertical width and 0.15mm horizontal width are formed on the metallic sheet 2 by the electric discharge machining using the comb-shaped electrode 1 for electric discharge machining having comb teeth 1a and consisting of tungsten. The electric discharge machining liquid is then removed and the chemical polishing liquid is passed in the slit holes 3 by using a pump 4 and is held for 10 minutes to smooth the inside surfaces of the slit holes 3 and to finish the slit holes 3 having the required sizes, i.e., the final finish sizes. The mask having the slit holes which are smooth in the inside surfaces and have the high accuracy is formed in such a manner.