| 摘要 |
PURPOSE:To obtain a nozzle plate which is free from burr and prevented from occurrence of damage at the time of cleaning, by increasing the hardness of nickel on surrounding area of the nozzle of the nozzle plate made of electrocast nickel. CONSTITUTION:In manufacturing nozzle plates 2 and 5 by forming a concave section 3 on one side of an electrocast nickel blank by precipitating nickel centering on a linear core member 1, and also by forming a nozzle 4 by etching remaining part of the core member 1, hardness of nickel is increased by reducing current density at the time of precipitating nickel in the neighborhood of the core member 1. In process A, at first, current density is lowered and hardness is raised, and for the remaining parts, current density is gradually increased to lower the hardness, and in process B, the current density is reduced to raise the hardness in the first and final portions. In both the cases of A and B above, the hardness is large on the surrounding area of the nozzle 4, and therefore, it is possible to prevent occurrence of burr at the time of formation of the concave section 3. Further, A is effective for prevention of deformation during processing, and B is particularly effective for prevention of occurrence of burr during processing of the end section. |
