A method of forming a plate with openings (10) having openings (14), the method comprising: providing a mandrel (26) comprising a mandrel body (28) having a conductive surface (30) and a plurality of islands non-conductive (32) arranged on the conductive surface, where the islands extend over the conductive surface and are inclined with respect to the conductive surface； place the mandrel in a solution containing a material to be deposited on the mandrel； apply electrical current to the mandrel to electrodeposite the material and form a plate with openings on the mandrel, where the openings (14) in the plate with openings are defined by a tapered portion that narrows inwardly from a lower surface (18) towards a upper surface (16) and a widened portion (24) extending from the upper surface to the lower surface and widening away from the tapered portion, and where the enlarged portion and the tapered portion share an axis of symmetry, and the openings have a diameter in the range of 1 micrometers and 10 micrometers at the intersection (22) of the tapered portion with the enlarged portion； and where the widened portion (24) has a diameter on the upper surface (16) that is in the range of 20 micrometers to 200 micrometers and a height in the range of 4 micrometers to 20 micrometers.Un método para formar una placa con aberturas (10) que tiene aberturas (14), comprendiendo el método: proporcionar un mandril (26) que comprende un cuerpo de mandril (28) que tiene una superficie conductora (30) y una pluralidad de islas no conductoras (32) dispuestas en la superficie conductora, donde las islas se extienden sobre la superficie conductora y están inclinadas respecto a la superficie conductora； colocar el mandril dentro de una solución que contiene un material que ha de depositarse sobre el mandril； aplicar corriente eléctrica al mandril para electrodepositar el material y formar una placa con aberturas sobre el mandril, donde las aberturas (14) en la placa con aberturas están
