I will start out this post by saying we are always game for trying out new projects. Over time we have learned what is possible, what is difficult but possible, and what is not possible when making stainless steel medical device components. We have also learned why device designers want to take certain approaches.
One consideration when deciding between taper vs. flat step vs. radius is whether or not the wire will be formed after the machining process. From our experience, if the form uses both sides of the step or radius, there can be many difficulties. For one, if you are planning to clip the wire to a form (cylindrical) and then heat set, the different sized radius wire will form differently. A second difficulty can be trying to put through a machine such as a coiler. Many times the radius or step may kink when going through the process. If the wire is going to be formed, we tend to suggest that the wire is tapered, to avoid the miscues.
Why use a flat step or radius vs. a long taper on a stainless steel medical device? We find that most steps and radii are used as a “catch” for some component that goes over it. For instance, you would slide on a coil until it catches on the stainless steel lip. You would then weld the two together at the step or radius.
I hope this helps dispel some myths and helps provide some guidance for stainless steel medical device designers who are working on their next great invention.