A method for manufacturing a pair of parallel micro machined channels, using a substrate of a first material and comprising the steps of: - forming two primary perforations in said substrate, spaced apart from each other by a distance that is larger than a width of the channels to be formed; - forming two channel outlines in said substrate, the two channel outlines being spaced apart from each other; - filling the outer circumferential surface of the two channel outlines with a second material, to form said first micro machined channel and said second micro machined channel; - forming two secondary perforations in said substrate, at positions radially outside of the micro machined channels formed in the previous step; - forming two ducts in said substrate, while ensuring that some of the substrate-forming first material remains present between the channels.