GB460687A - Master plate for making sieves and other perforated metal articles and method for manufacturing such master plate - Google Patents

Abstract

460,687. Manufacture of perforated articles by electrodeposition. BEYNEN, L. R., and DORP, B. M. VAN. April 6, 1936. No. 10093. Drawings to Specification. [Class 41] In a mould for the production of sieves or the like by electrodeposition the exposed conductive portions are made of a material such as a mercury amalgam which is repellent to the insulating resist separating them or a material such as lead or a lead alloy which is so repellent when wetted. In an example a polished copper plate is covered with a lightsensitive medium and exposed to light through a screen. It is developed and washed leaving raised points which may then be burned in. The exposed metal parts are then slightly etched, and a thin layer of lead is electrodeposited thereon. The plate is then cleaned and moistened with water and a fatty ink is applied which adheres to the raised points but not to the lead. The plate is then dusted with asphalt powder which is afterwards removed from the metal surfaces. That remaining on the projections is melted. The mould is then ready for use ; a parting layer to facilitate removal of the deposit may be applied. The insulation may be removed when desired leaving cups which are refilled with fresh insulation. Alternatively the original insulating material may be removed by treatment with heated lye after deposition of the lead, and the cups so formed filled with fatty ink. If a metal other than lead or a lead alloy is employed as the conductive surface of the mould it may be rendered water-retaining by graining and treatment with gum arabic before application of the insulating resist.