METHOD TO FABRICATE A NEEDLE HAVING A TAPERED PORTION BETWEEN A DISTAL TIP AND A LONGITUDINAL CHANNEL

摘要

A novel method to fabricate a needle includes stamping an elongated shape in a flat metal sheet. The elongated shape defines a longitudinal axis and two edges that are substantially parallel to the longitudinal axis. Each of the two edges includes an inward curve with relative alignment to create a relatively narrow neck. A longitudinal channel is formed to give the elongated shape a U-shaped cross-section in a plane normal to the longitudinal axis. The method includes punching through the neck with a punch that slides along a punching axis that intersects the longitudinal axis with an angle in the range 15° to 50°. Alternatively the method includes coining a thinned region that spans the neck and may define a V-shape in a major plane of the flat metal sheet, and separating the elongated shape along the thinned region after coining.