Laser cutting now takes on intricate microstructures; new-generation laser boosts productivity and quality in stent manufacturing.

Author:Vollrath, Klaus
Position:Medical: machining

Stent manufacturing processes currently involve few automated operations and lack closed-loop-process control procedures. New stent generations call for more uniform characteristics and thus for a significantly higher degree of process control. A key element for achieving these aims is a state-of-the-art diode-pumped fiber-laser cutting system excelling by speed, accuracy, and an outstanding level of process control capability.

"The emergence of new generations of stents creates the need for an in-depth redesign of the manufacturing process chain as a whole," says Michael Giese, CEO of eucatech AG in Rheinfelden, Germany, an innovative manufacturer of medical technology for interventional cardiology and radiology with a specific focus on stent systems and related application equipment.

Stents are expandable metal-grid structures used to stabilize weakened blood vessels--for example, in a patient after the removal of clogging coagulations. Standard procedure for their application is the introduction using a specialized catheter and a subsequent expansion by a ballooning tip section. Alternative technologies using memory-effect alloys have become available as well. Stents are produced from thin-walled tubes made of high-quality metal alloys such as stainless steel, cobalt-chromium alloys, or memory- effect alloys such as Nitinol. The filigree, intricate grid structures that are the prerequisite for achieving their impressive diameter expansion ratios, are produced using precision laser-cutting technology. With the challenges resulting from new developments, manufacturers have to focus on the stability and uniformity of cutting-process results.

Total quality management

"As any foreign material inserted into the body, a stent will interact with its environment, creating an irritation that might interfere with the healing process," explains Giese. New developments thus include stents with drug-eluting coatings consisting of a biodegradable matrix releasing suited drugs such as Paclitaxel over a period of eight to 10 weeks after insertion. But this improvement also generates higher requirements to be met by manufacturing processes as this automatically implies additional validations and approvals by bodies such as the U.S. Food and Drug Administration (FDA). To ensure appropriate drug dosing, there is prescribed a very restricted scatter bandwidth for the total surface area of the stent, thus significantly narrowing manufacturing allowances from...

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