Butt End Treatments

Radius is a rounded edge. The degree of roundness can be specified and is measured in length. A radius is used on the butt-end to aid in assembly or to smooth corners on a notch.

Chamfer is an operation where the butt-ends of the tubing are ground off at an angle to reduce O.D. This creates a smooth edge for high speed assembly. This tip is also known as a knife edge (if chamfered to be sharp). Chamfer angle or chamfer length is used to specify the amount of chamfer.

Flare end expands both the I.D. and the O.D. Once expanded, it provides a funnel to the I.D. A flared end also aids in molding applications. The flare diameter is specified at the greatest point.

Grit blast is produced when media is shot against the cannula under high pressure. This process creates a raised and roughened surface on the cannula. Grit blasting can be used to increase the surface area of cannula for adhesion in injection molding applications. It may also be used as one method to increase reflective area of cannula to improve visibility in ultrasound applications (see Echogenic tip). The angle of application, pressure of application and type of media used can all be varied. Grit blast can be measured as a roughness average (Ra). Grit blast is also referred to as an aluminum oxide or media blast.

Notch for Bevel Orientation is a notch which is ground in the butt-end of cannula. It is used to orient the cannula bevel for automated assembly.