Mask etching procedure of a puncture element (14), which has an elongated rod (16), a tip (18) protruding distally and a collecting channel (22) open laterally for a body fluid extending along from the stem (16) up to the region of the tip (18), in which a bilateral engraving mask (10) is applied on both sides of a substrate (12) and the puncture element (14) is formed as molded piece of engraving under the action of an engraving agent, in which one side of the channel (28) of the engraving mask (10) is provided with a groove of channel engraving (38) for unilateral engraving of the collecting channel (22), characterized in that a proximal and / or distal end portion (40, 60) of the channel engraving groove (38) is made by narrowing in the direction of the end of the groove, by the fact that the engraving mask (10) is provided with a flange forming region (62) adjacent to the channel engraving groove (38) in the proximal direction, and by the fact that a flange edge (68) forming the mouth of the collecting channel (22) is generated in a proximal retention part (20 ) of the puncture element (14) by subgravure of the flange formation region (62).Procedimiento de grabado por máscara de un elemento de punción (14), que presenta un vástago alargado (16), una punta (18) que sobresale distalmente y un canal colector (22) abierto lateralmente para un fluido corporal que se extiende a a lo largo del vástago (16) hasta en la región de la punta (18), en el cual una máscara de grabado bilateral (10) es aplicada en las dos caras de un substrato (12) y el elemento de punción (14) es formado como pieza moldeada de grabado bajo la acción de un agente de grabado, en el cual un lado del canal (28) de la máscara de grabado (10) está provisto de una hendidura de grabado de canal (38) para el grabado unilateral del canal colector (22), caracterizado por el hecho de que una parte de extremo proximal y/o distal (40, 60) de la hendidura de grabado de canal (38) está realizada estrechándose
