Influence of materials selection and quality on ink jet nozzles fabricated by micro-electrodischarge machining

Ink jet nozzles require accurate definition and smooth surface finish to promote laminar flow of ink and prevent turbulence. Recent investigations into micro-electro discharge machining of nozzles in thin stainless steel have shown that surface finish is dependent not only on machining parameters but also on material selection and quality. Defects within the material such as cracks, aligned to the direction of rolling, are a source of random defects within nozzles after machining. They can cause severe problems by acting as sites for ink-flow perturbation and corrosion and thereby cause defective printing. Evaluation of material quality at the microscopic level prior to machining is therefore recommended to avoid a waster of machining-time on sub-standard material and the resultant low yield of acceptable nozzles. Image analysis of a range of materials has shown that some materials examined contained relatively few defects.