How do you make a one-piece silicone medical tube that has one lumen on one end and two lumens on the other? Or three lumens changing to two? A tubing processor, Specialty Silicone Fabricators in Paso Robles, Calif., has the answer. It recently patented methods of changing the shape, number, and location of lumens by raising and lowering tines in the die mandrel.
In one example (U.S. Patent # 6394141), an oval profile transitions from three lumens to two by raising one tine, allowing plastic to flow where the tine had been. Specialty Silicone calls the process geometric transitional extrusions, or Geotrans and uses it to start and stop lumens without couplings or joints. Lumens can also join, forming a Y-shape, or spiral or twist within the tubing to prevent kinking. The company currently uses the patents only for silicone, but they could be used for other extrudable products, and the company would consider licensing the technology. Tel: (805) 239-4284 • www.ssfab.com