The design of the extrusion die significantly affects both the extrusion process and the quality of multi-lumen tubes. Traditional design methods that rely on trial and error tend to increase manufacturing time and costs while diminishing product quality. This study utilizes inverse extrusion simulation and optimization to design the extrusion die without the need for trial and error. The inverse extrusion simulation generates the die profile necessary to achieve the desired extrudate shape. Subsequently, direct extrusion simulations are conducted to predict the extrudate profile based on the derived die. The optimal volumetric flow rates of air within the lumens are also identified to ensure the extrudate meets the target profile. The results from the direct extrusion simulation, combined with optimization, confirm that the designed extrusion die can successfully produce the target profile. Using the derived die, the multi-lumen tube with the desired specifications is successfully extruded. This design and manufacturing approach enhances both the quality and productivity of multi-lumen tubes.

Balloon catheters are a key technology in medical devices, essential for minimally invasive procedures. This study quantitatively analyzes how the orientation characteristics of polymer tubes, influenced by extrusion conditions, affect the mechanical properties and compliance of the final balloon—where compliance refers to the change in diameter under external pressure. Nylon 12 tubes, with a target outer diameter of 1.2 mm and an inner diameter of 1.0 mm, were extruded under six different orientation conditions by varying the screw flow rate and puller speed. The tubes were processed under identical forming conditions, allowing for a consistent evaluation of their mechanical properties. As orientation increased, elongation decreased while yield strength increased, and these trends continued in the balloon, significantly influencing compliance. To quantitatively measure orientation, we introduced the dimensionless Deborah number. We established a curve-fitted experimental model that links extrusion conditions, polymer tube properties, and balloon compliance. This model allows for the prediction of balloon performance based on extrusion-stage parameters, providing a practical framework for process optimization. Overall, this study offers an effective quantitative indicator for forecasting balloon catheter performance based on extrusion conditions and supports the systematic design of medical balloon products.

As the market for minimally invasive procedures developed rapidly, there was an increase in the demand for high-precision, high-performance catheter fabrication technology. Sheath and dilator tubes are essential intervention devices for procedures, in which catheters are used and require precise dimensional accuracy, and uniform roundness and surface roughness. Polyethylene is used in sheath and dilator limitation for processability, which causes low melt flow index and side effects. Therefore, in the extrusion process using polyethylene, it is important to study the manufacturing of tubes with improved roundness and surface roughness. In this study, we proposed a calibrator for precise production with an aim to manufacture 5Fr micro-puncture tubes, and studied the changes in the roundness and surface roughness of tubes by changing the cooling water temperature and water disk thickness. As a result, it was found that the cooling water temperature and wafer disk thickness had an effect on the roundness and surface roughness, and the roundness had an effect on the formation of the wall thickness. Therefore, these experimental results were used as a study for the production of improved Sheath and Dilator tubes.

The multi-lumen catheter with complex and small cross section is widely used for interventional radiology and minimally invasive surgery. It is manufactured in the polymer extrusion process with many manufacturing parameters. The profile of the extrudate is difficult to predict because it depends on the die shape and many parameters. In this paper, the effects of the manufacturing parameters for multi-lumen catheter extrusion are studied. The commercial software ANSYS Polyflow is used to simulate the polymer flow and predict the profile of the extrudate. The optimized die shape is used to achieve the target profile of the extrudate. The extrudate profiles are investigated with respect to the puller speeds at the end of the extrudate and blowing air pressure of each lumen. Circularity and major diameter are compared for the different manufacturing parameters. The effects of the manufacturing parameters on the profile of the extrudate are examined. The target profile of the extrudate is obtained with optimized manufacturing parameters.