Medical tubing makers need to carefully control and tune their extrusion tooling to very tight tolerances in a cost-efficient manner. Flow channel geometry plays a critical role.
Denis Finn, Guill Tool & EngineeringThe extrusion process brings with it several challenges, and a frontrunner is product quality, especially when it comes to extruded medical products.
Medical tubing and jacketed products must be produced to conform to very tight tolerances. It’s often necessary to inspect wall thicknesses and diameters to tolerances lower than 0.0004 in./.01 mm. Polymers used in the medical industry may also be extremely expensive. Medical tubing makers need to carefully control and tune extrusion systems to produce demanding products in a cost-efficient manner. This is especially important for multi-layer and/or multi-lumen constructions.
The flow channel geometry the polymer flows through is a critical component of a well-designed extrusion system. Residence time, or the amount of time the polymer flows through the die assembly, should be considered in an effort to avoid burning and stagnation issues. Channels that are too large means the polymer’s exposure time to processing temperatures could begin to degrade the polymer. A too restrictive geometry often means the system will run at high pressures, often limiting production speeds. Along with this, users can encounter dead spots that prevent the material from flowing freely. If this is not corrected, the material can become completely degraded.