Conair shows off precision "MedLine" puller/cutter in advanced medical tubing extrusion demonstration

Working closely with extruder and instrumentation suppliers, Conair has been demonstrating its "MedLine" puller/cutter in a working extrusion line configured to produce the precision small-diameter medical tubing used for heart and brain catheters.

Made of a special medical grade of urethane, the microbore tubing is referred to as tapered or "bump" tubing because the outside and inside diameters (OD and ID) are precisely adjusted periodically to widen the tube at a point where the catheter would be attached to other medical equipment. Nominal outside diameter for the tubing produced on the show floor will be between 0.060" and 0.070", with a 0.045" wall thickness.

The MedLine puller/cutter employs advanced servo-drive and control technology to precisely vary puller speed and air pressure to produce the tapered bump sections and trigger the cutter blade to cut the tubing at exactly the right place to yield a nearly finished catheter tube. The extrusion line also includes a small Conair HighTech flood-cooling tank, which includes special features required by medical manufacturers. Cooling water is supplied by a Conair portable chiller, and the hygroscopic urethane material is dried prior to extrusion by a Carousel Plus W-15 desiccant dryer.

An advanced touch-screen controller uses faster microprocessors and new software to make complex set-ups easy and intuitive.

The MedLine units are also equipped with a new kind of puller belt. Instead of a conventional poly-V belt, which tends to slip on the drive pulleys, Conair uses an alternative PD timing belt that is self tracking and does not slip. The new belts are also made of FDA-approved materials throughout, in contrast to conventional belts that must be coated on contact surfaces for FDA compliance.

The cutter portion of the unit also features a standard positional servo drive system, which provides cut response repeatability within ±0.1ms — a ten-fold improvement over conventional velocity-based servo systems.