Medical Extrusions: The Backbone of Advanced Catheter Systems

If you’re in the business of designing catheter-based medical devices, you know that medical extrusions are where it all starts. Whether it’s a guide catheter, a delivery sheath, or a balloon catheter, everything depends on high-quality extrusions with the right balance of flexibility, strength, and precision.

But let’s be real—getting extrusions right is tough. Engineers face a host of challenges when designing tubing that meets the exacting demands of modern catheter systems. From achieving tight tolerances to creating complex multi-lumen configurations, the extrusion process isa blend of science and technique. Let’s dive into some of the biggest hurdles and how to overcome them.

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The Challenge of Tight Tolerances

Catheter performance depends on precision, and that means micron-level accuracy in extrusion dimensions. Even the slightest variation in inner diameter (ID), outer diameter (OD), or wall thickness can impact how a catheter tracks through vasculature, interfaces with other components, or delivers therapy. Maintaining such tight tolerances requires:

• Precision tooling and die design to ensure consistency across long extrusion runs.
• Careful material control—different polymers behave differently during extrusion, and understanding shrinkage and expansion properties is key.
• Real-time monitoring and feedback loops to detect variations before they become a problem.
• Years of experience working with thin wall and tight tolerance extrusions to understand the physical boundaries of extruding thermoplastic materials.
• Drawdown ratios: depending on the size and material of the extrusion, the drawdown ratio will inform what size extruder is needed.

Thin-Wall Extrusions: Balancing Strength and Flexibility

With the push toward less invasive procedures, catheters need to be thinner and more flexible while still maintaining torque control and kink resistance. That’s where thin-wall extrusions come into play—but making them isn’t easy. The thinner the wall, the more difficult it is to keep uniform thickness without weak spots.

Overcoming this challenge involves:

• Material selection—some polymers provide better strength-to-thickness ratios, making them ideal for thin-wall applications.
• Process optimization—careful temperature control and extrusion speed adjustments are critical to avoid deformities.
• Post-processing techniques like annealing to relieve stresses and enhance mechanical properties.

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Multi-Lumen Extrusions:

Some catheter designs require multi-lumen extrusions, where multiple channels run through a single tube to accommodate guidewires, drug delivery, or other functions. The challenge? Keeping those lumens uniform and preventing collapse or distortion during extrusion.

Key considerations include:

• Designing the right die—multi-lumen dies must ensure even material flow to prevent the formation uneven septal wall thicknesses.
• Balancing wall thickness—uneven walls can cause problems during bonding, skiving, or interfacing with other components.
• Material compatibility—different materials shrink at different rates, making co-extrusions or multi-layered structures even more challenging.

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Making Prototyping Faster & Easier

Developing a catheter from scratch can be time-consuming, especially when waiting for custom extrusions. That’s why we offer a wide range of off-the-shelf single-lumen extrusions and dilators in standard catheter development sizes from 2 to 36 French, with multiple wall thickness options. These ready-to-go components help engineers quickly iterate on designs and accelerate time-to-market.

In order to make prototyping and ordering extrusions even easier, MIS has developed IQueue: the online extrusion ordering platform. With IQueue, engineers can enter their custom extrusion specifications, choose from a wide range of in-stock resins and lead-time options, and instantly place an order via credit card or purchase order. You can try IQueue by signing up at www.midwestint.com/iqueue.

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Let’s Build the Future of Catheters—Together

Medical extrusion may be a behind-the-scenes process, but it’s at the heart of every successful catheter design. Whether you need high-precision thin-wall extrusions, complex multi-lumen tubing, or off-the-shelf components to kickstart your next prototype, we’ve got you covered.

Let’s work together to turn your catheter designs into reality!

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