A METHOD FOR CHEMICAL ETCHING OF A NEEDLE CANNULA

摘要

A regular metallic, cylindrical tubular needle cannula (1) is subjected to a metal etching liquid (21) in the inside lumen (4) thereby increasing the inside diameter and enhancing the flow properties while maintaining the outside appearance. The inside diameter is only increased over a controlled length (7) of the full length of the needle cannula (1) leaving sufficient length and wall thickness to also taper the outside diameter.