Low elastic recovery and the presence of lube additives included to provide slip are two traits in a thermoplastic polyurethane (TPU) film or sheet grade that can be detrimental when it comes to medical manufacturing. The former can cause wrinkling when the TPU is applied to material with high elasticity and high-elastic recovery, and the latter can cause contamination. Developers at Deerfield Urethane Inc. (Whately, MA; www.deerfieldurethane.com) believe that two new products in their Dureflex line will provide medical manufacturers of a variety of products with the advantages of TPU material, without the drawbacks.
For three years, engineers at Creganna Medical Devices (Galway, Ireland; www.creganna.com) scratched their heads over how to join nitinol to stainless steel to produce a catheter that exhibited the performance of nitinol without the associated high costs. For the past year, the company has actually been developing the nitinol–to–stainless-steel-tube welding technology that provides the elusive answer to a question posed for years by manufacturers.
More than 50 stent manufacturers are using an ultrasonic coating system from Sono-Tek (Milton, NY; www.sono-tek.com). Users of the Medi Coat equipment report holding coat consistency within 3% and transfer efficiencies of 30% to 70%. With older spray processes or dip coating, variations range from 5 to 7% and efficiency averages between 7 and 15 %.