Annular Parts (Stents)

Design a repeatable portion in a flat sketch; if for example you can repeat the pattern every 90 degrees layout a flat sketch whose baseline is exactly (to as many decimal places as possible) 1/4 of the circumference of your final diameter.

After you've layed out your sketch you can extrude as sheet metal and use an insert bend to roll it to your desired radius (note: you need small extension extruded prior to rolling that you can cut off later to make this work) or use the wrap command to wrap the sketch onto a cylinder with the scribe option. Use this to make a split line on the cylinder, then surface offset, then surface thicken.

Zander

Here's a link to a thread on this subject which might help?...