| 摘要 |
PURPOSE:To obtain a surface-roughening method for a base for a planographic plate free of scumming or thinting and having satisfactory durability to repeated printing, by causing a high-velocity jet of a high-pressure liquid to be joined by a slurry containing a specified abrasive jetted from a jetting port, and the joined jet is caused to impinge on the surface of an aluminum plate. CONSTITUTION:In a liquid honing method for roughening the surface of an aluminum plate, a flow of a slurry jetted from a jetting port is made to join a flow of a high-pressure liquid jetted from a nozzle. It is necessary that the liquid is jetted from the nozzle at a flow velocity of 31-140m/sec. The slurry may be jetted at a velocity of about 2-25m/sec. The slurry comprises water and a particulate abrasive, the concentration of which is about 5-80wt%, usually about 30-50wt%. It is preferable that the abrasive has a specific gravity of not less than 2.5, has an acute-angular shape with a radius of a tip part of not more than 20mum, retains the acute-angular shape even after impinging on the aluminum plate, and contains not less than 8% of Si. |
