GB914222A - A method of making a perforated plate having capillary orifices - Google Patents

Abstract

914,222. Making spinnerettes; electroerosion. ENGELHARD INDUSTRIEN A.G. July 11, 1961 [July 14, 1960], No. 25141/61. Classes 83 (2) and 83 (4). A workpiece 7 has an orifice of non-circular cross-section formed therein by electro-erosion and which is subsequently finished by mechanical working. In the manufacture of spinerettes for the production of glass or nylon filaments or the extrusion of spaghettis and noodles, a plate 7 of steel, tungsten carbide or tantalum carbide has blind holes 8, 9 bored in one face corresponding to the required positions of the orifices. This plate is located by a guide pin 5 upon a conductive base 3 mounted within a bath 1 containing kerosene 2. An electrode 12 with a tip 15 of the required Y or cruciform cross-section, Figs. 3, 4 (not shown), is then advanced through the plate and into one of the blind holes. When all the orifices have been eroded, they are broached to size in a plurality of operations using increasing size of broach, Figs. 9-12 (not shown). Finally, the burr resulting from the broaching is removed by electro-erosion, Fig. 16 (not shown). The initial blind holes may have walls of hyperbolic, parabolic or conical shape or these holes may be omitted. Instead of broaching, the orifices may be finished by polishing using an ultrasonically oscillating rod and grinding paste. In another embodiment, Fig. 17 (not shown), the orifices are formed in tungsten carbide inserts which are fitted into a steel plate.