The Vertical Reflow Machine: The Unsung Hero Powering Catheter Innovation

Loading a catheter onto a vertical reflow machine

Walk into any catheter development lab or prototyping space, and you’re bound to spot it: a trusty vertical reflow tower humming away in the corner, quietly making tough builds look easy. This is the tool engineers lean on for its unfussy reliability and ability to tackle seriously complex lamination work. Today, let’s break down what makes vertical reflow such an unsung hero, hear from real-world experts, and explore how this workhorse machine helps R&D teams navigate tricky design hurdles.

Reflow, sometimes called lamination, is a key stage in advanced catheter fabrication. Instead of relying solely on extrusion (think Play-Doh Fun Factory), the reflow process involves adding different layers, reinforcing wires, and specialty materials into a loose assembly. It’s a meticulous step, often requiring several polymer transitions and the deft hands of lab techs working under the microscope. Once assembled, the device gets snugged inside a high-temp FEP heat-shrink tubing, chosen for its non-stick properties and ability to constrict evenly without leaving residue. When the catheter passes through the vertical reflow machine, the heat-shrink compresses everything together, while hot air from the reflow precisely melts and fuses the underlying plastics. The result is a catheter with a strong, seamless profile, where each zone’s properties are tightly controlled.

Engineers who’ve spent days troubleshooting lamination issues know this step can make or break an entire batch. If layers aren’t joined thoroughly, or the braid becomes exposed, minor defects at this stage can ripple through to rejections or even patient risk down the line. That’s why smart process design and the right equipment are so essential … but more on that in a moment.

Why Engineers Favor the Vertical Method

At first glance, the Pilot Line vertical reflow unit might just look like a tall “coffee can” filled with hot air, but its unassuming design hides a sophisticated level of control. The nozzle delivers 360-degree airflow, allowing polymers and reinforcements to melt and blend with remarkable uniformity along the full length of the device. Meanwhile, the heated FEP heat-shrink works like an industrial squeegee, compressing the layers and pushing out air so every braid or coil ends up fully encapsulated.

Setting up reflow with this unit is pretty straightforward: just clamp the device, punch in your parameters on the touchscreen, and let the machine do the rest. There’s no need for compressed air, no tricky electrical requirements, and minimal floor space requied, which is especially appealing to innovation-minded R&D teams and startups trying to ma

e the most of limited space and budgets.

It’s on the production floor that this approach really earns its stripes. As soon as teams start running batches, the value becomes clear: ease of setup and repeatability translate into less downtime and more consistent output with every cycle

The benefits of vertical reflow show up in real-world outcomes, especially when it comes to yield. Teams often report significant improvements after making the switch. For example, one longtime user reported seeing their usable product rate jump from about 50% with legacy systems to 95% or more on these machines. Just as importantly, this leap in performance doesn’t come at the cost of flexibility: labs can run multiple units in parallel, gaining efficiency without dedicating massive floor space or budget to oversized, industrial alternatives.

A pair of vertical reflow machines share a common base to save space

That’s a big part of why vertical reflow keeps popping up on engineers’ shortlists for process upgrades or new device lines. The combination of reliability, adaptability, and efficient footprint means teams can tackle more ambitious projects … without hitting speed bumps due to equipment constraints or spiraling costs

Vertical vs. Horizontal: Real-World Differences

Why choose a vertical reflow over a conveyor-style horizontal oven? The difference often boils down to control and adaptability. Horizontal ovens apply uniform heat along the length, which works great for basic builds but falls short for complex devices that combine soft tips, stiff shafts, and reinforced segments. The vertical tower excels by letting engineers ramp the heat up or down for each section; ideal for nuanced, multi-material geometries.

Stephen Garber, Senior Applications Engineer at MicroLumen, Inc., shares, "For some more complex catheter builds, we need to quickly pass the heating nozzle over much of the catheter length, and then slowly over specific sections (to reflow only those sections). The Pilot Line vertical reflow tower UI has been perfect for programming part-specific R&D protocols like this."

Unlike horizontal oven systems, which treat an entire device with the same temperature profile, vertical reflow allows the operator to adjust parameters section-by-section, responding to each material's need for more (or less) heat. This flexibility leads to fewer rejects and enables finer manipulation of advanced catheter designs, especially when working with multiple material transitions or tightly-packed reinforcements. And for teams facing space constraints, vertical reflow offers a smaller footprint and more ergonomic workflow, fostering better consistency and improved outcomes in a busy R&D environment.

Damian Carr, author of The Catheter R&D Handbook, adds, "When it does come to laminating polymers, don't underestimate the power of gravity. Vertical lamination provides a higher control of the profile, while also taking up less than half of the floor space (in Pilot Line’s case, less than a quarter of the space!)"

Pilot Line’s machines ship as standard parcels, slide easily into any lab on regular wiring, and can be grouped in tight clusters. That kind of flexibility is rare among reflow systems; We’ve seen engineers mount three reflow units to a shared base for parallel operation, all with independent control. The fast response of the heaters means zone temperature changes can be dialed in for ultra-fine control, down to mere fractions of an inch, making every R&D iteration efficient.

Experienced engineers know that successful reflows depend as much on careful prep as on machine choice. Pay close attention to how polymers are joined before heating: gaps can cause weaknesses and kinks, especially in bends. OD/ID sizing can require multiple extrusion trials to dial in, so start with solid estimates and adjust. While the vertical reflow tower won’t fix prep errors, its stable, repeatable heating gives teams the best shot at consistent, problem-free results.

Why Vertical Reflow Is a Catalyst for Innovation

Vertical reflow has become a staple for device engineers who value the freedom to iterate, experiment, and progress their designs without constant process roadblocks. From early-prototype workbenches to busy pilot lines, the story is the same: reliable, straightforward manufacturing methods empower teams to spend less time troubleshooting and more time refining devices for clinical impact. This approach makes complex lamination practical, consistent, and accessible, allowing product developers to push boundaries and bring sophisticated technologies closer to patients who need them most.

Why Coil Angle Matters - and What We Did About It

Let’s talk about coils. Those unassuming spirals of wire are hiding in plain sight everywhere. From the guidewires in minimally invasive medical procedures to the cable housings for your bicycle brakes and the heating elements in your toaster, coils are essential to modern life. At Pilot Line, we’re often asked about the basics of coil winding-especially the difference between open pitch and closed pitch coils. With the launch of our upgraded coil winder, we thought it was the perfect time to offer a practical overview of how coil winding works, why precision matters, and where these spirals end up.

Making Open Pitch Coils

Open pitch coils are characterized by the visible gaps between each turn of the wire. These spaces are intentional and give the coil flexibility, making them ideal for applications where bending and movement are important but where the coil doesn’t need to resist crushing forces.

On a coil winder, open pitch coils are made by precisely coordinating the rotation of the mandrel (the rod or tube the wire is wound around) with the lateral movement of the wire feeder. The pitch—the distance from the center of one wire to the next—is set by adjusting the speed at which the feeder moves relative to the mandrel’s rotation. Achieving a uniform pitch is crucial, especially for medical devices, as even slight inconsistencies can affect the performance and safety of the final product.

The process requires careful tension control. If the tension is too loose, the coil can end up sloppy and inconsistent; too tight, and it becomes difficult to remove the mandrel from a catheter with the coil wound in place.. Pilot Line’s coil winders are designed to maintain this balance, allowing users to program precise parameters for each project.

Closed Pitch Coils and the Importance of Angle

Closed pitch coils, on the other hand, are tightly wound so that each turn of the wire is in direct contact with the next. This design gives the coil strength and resistance to crushing, which is essential in applications like endoscope shafts, control cables, and any structure that needs to maintain its shape under compression.

Winding a closed pitch coil is a more demanding process. The key variable here isn’t just how fast the feeder moves, but the angle at which the wire is laid onto the mandrel. Even minute variations in wire diameter can accumulate over hundreds of turns, leading to a coil that gradually opens up or overlaps itself, neither of which is acceptable in high-precision manufacturing.

To solve this, our upgraded coil winder uses a machine vision system called the Angle Pilot. This system employs a video microscope to continuously measure the lay angle of the wire as it’s wound. If the angle drifts, the machine automatically adjusts the feeder speed to bring it back in line. This real-time feedback loop ensures that even with ultra-fine wires, the coil remains consistent from end to end.

Maintaining the correct angle is also critical for controlling the coil’s preload, or the internal tension between the turns. A coil wound with too steep an angle may have too much preload and be difficult to bend. Too shallow, and the coil will lack the necessary strength. The Angle Pilot makes it possible to dial in exactly the right amount of preload for each application, which can be tested with methods like the “droop test” (measuring how far a coil can extend horizontally before bending).

Coils in Medical Devices: Small, Precise, and Essential

In medical manufacturing, the stakes for coil quality and precision are exceptionally high. Coils are used to reinforce guidewires, catheters, and steerable instruments, where they must be flexible enough to navigate the human body but strong enough to transmit force and resist collapse. The dimensions involved are astonishingly small; Wires can be as thin as a human hair, and tolerances are often measured in ten-thousandths of an inch.

Achieving this level of precision means every aspect of the coil winding process must be tightly controlled, from the pitch and angle to the tension and speed. Pilot Line’s machines are designed with these requirements in mind, offering programmable recipes and advanced monitoring to ensure every coil meets the exacting standards of medical device engineering.

Supporting Every Spiral

Coils may not spend a lot of time in the spotlight, but they’re critical to the function and reliability of countless products. Whether you’re developing a next-generation catheter or building industrial heating elements, understanding the basics of coil winding—and the difference between open and closed pitch designs—can help you choose the right approach for your needs.

Pilot Line is proud to support engineers and manufacturers across industries with tools that make coil production more precise, efficient, and customizable. We’re always excited to see the creative ways our machines are put to use, and we’re here to help you wind the perfect coil, no matter your application!

The Green Revolution in Medical Device Coating

As manufacturers of catheters and guidewires, you're well aware of the importance of hydrophilic coatings in ensuring these devices glide smoothly through blood vessels. But have you ever stopped to think about how these coatings are applied? Recent advancements in coating technology are not only improving the efficiency of this process but also making it more environmentally friendly. Let's explore how these innovations are transforming the manufacturing landscape.

The Old Way: Energy-hungry and Inefficient

Traditionally, coating medical devices has been a bit of an energy hog. The machines used to apply and cure these coatings have typically relied on mercury vapor lamps, which are about as efficient as leaving your oven on all day to make toast. These old-school systems can burn up to 2000W of power, and they often stay on all day long due to their long warm-up times.

The coating process itself is quite simple, but must be very carefully controlled. As you know, many catheters, guidewires, and guide sheaths are coated with a hydrophilic coating; a polymer that readily absorbs water. This coating lubricates the device, allowing it to glide smoothly through blood vessels. The application process usually involves dipping the device into a bath of coating solution and extracting it at a controlled speed to ensure uniform coverage.

After application, the coating needs to be cured. While some coatings cure with heat, many require UV light. This is where those energy-hungry lamps come into play. Traditional machines might use fluorescent, mercury vapor, or even microwave lamps to generate the necessary UV light. These light sources have several drawbacks: they take time to warm up, lose power over time, and often emit a broad spectrum of light, including unwanted heat.

The LED Revolution: Efficient and Eco-Friendly

But here's where things get interesting. New coating machines are hitting the market that use LED technology instead. These aren't your average LEDs, though. We're talking about specialized UV LEDs that emit light deep into the UV spectrum as low as UVC – perfect for curing those hydrophilic coatings that make medical devices so slippery and easy to use.

The benefits of these new LED-based coating machines are numerous:

LED UV Curing Chamber

• Energy efficiency: They use only about 70W of power while running, compared to 2000W for traditional systems.

• Instant start-up: Unlike old lamps that needed

  warm-up time, LEDs are ready to go instantly.

• Mercury-free: LED systems don't contain mercury, making disposal simpler and far more environmentally friendly.

• Consistent output: LEDs maintain their light output over time, unlike traditional bulbs that degrade.

• Targeted wavelength: LEDs emit light at specific wavelengths, reducing wasted energy on unnecessary parts of the spectrum.

Our own Automatic Coating Machine ticks all of these boxes, and is nearly 100x more power efficient than older models. 

Precision and Consistency: The Future of Coating Technology

This new generation of coating machines is changing the game when it comes to the coating process itself. Many now feature dual dipping stations, allowing for the application of both primer and top coats in a single automated process. The level of control is impressive. Some machines allow operators to set two distinct retraction speeds along the device length, enabling variable coating thickness where needed. After dipping, the coating can be dried using heated forced convection before being cured in the UV chamber.

Hydrophilic Coating Machine, with LED curing chamber opened

These processes are automated and programmable, which means more consistent results and less human error. Many systems even allow for multiple user-defined recipes to be stored, ensuring repeatability across production runs. All of this adds up to coating techniques that are quicker, cleaner, and far more energy-efficient.

We at Pilot Line believe the future of medical device coating encompasses both creating better products and doing so in a way that's kinder to our planet. And as medical device manufacturing continues to evolve, we are proud to contribute innovations that improve product quality while simultaneously reducing environmental impact. By dramatically reducing energy consumption, eliminating hazardous materials, and improving process control, these new coating machines are a perfect example of how technology can help us work smarter and greener.

Click here to learn more about Pilot Line's coating machine