Geometric transitioning allows for silicone tubing to change cross section during the extrusion process to eliminate molding and secondary bonding steps. This process reduces total cost of ownership for device manufacturer while improving part quality, device function and hygienic design. With GeoTransTM technology, assembled joints that may be weak, create additional failure modes or internal misalignments, where fluids can become turbulent or stagnate, can be eliminated.
HCR silicone’s unique green strength, the strength of rubber in its unvulcanized state, allows for highly complex geometries in continuous extrusion processes. In the GeoTransTM process, tool components can be moved during extrusion to change cross sections substantially. This opens up new design possibilities in a wide range of medical devices, including wound drains, spinal and hemodialysis catheters.
A major advantage to the device manufacturer is that overall processing time and costs can be lowered. Although running a simple extrusion is faster than running a geometric transition extrusion, overall manufacturing, assembly, and quality testing time can be significantly reduced with the GeoTransTM process. For instance, the production volume of many long-term implants does not justify complex, automated assembly. However, a redesign to include a geometric transition can eliminate the need for manual assembly of a portion of the device.
Additionally, with less components and secondary processes the design validation step may be significantly shorter, and it can be easier to meet international standards and regulatory requirements for a single part, due to risk mitigation.
The technology is applied to custom applications with precision tolerances. Typical changes include:
- Transition of a tube from a single to multiple lumens or splitting a multi-lumen tube into two or three single lumen tubes
- One or more lumen stops and restarts within a multiple lumen tube, eliminating the need for secondary operations, such as backfilling a lumen used for filling a catheter balloon
- A wound drain that comprises three separate pieces; an extruded tube, complex cross-section extrusion and molded hub, can be created as a single extrusion with two or more distinct geometric cross-sections and a smooth, integrated transition instead of a hub
- Off-ration bump tubing, for applications requiring a variable outer diameter with either a constant or variable inner diameter, can be created with very short transitions down to fractions of an inch
- Bifurcated tubing, which traditionally has four components: a two-lumen tube, two single-lumen tubes, and a molded hub, can be produced in one extrusion process
The GeoTransTM extrusion process has been used to manufacture products between 7 French and 24 French (on the catheter scale).