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Precision Cutting Stents with Fiber Lasers

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Last year in the United States alone, nearly 2 million stents were implanted in heart patients to help improve overall health as well as save patient lives. With so much riding on the effectiveness of these life-saving devices, stents demand the highest precision and quality control during manufacturing. To meet the medical industry’s stringent requirements, stent manufacturers have turned to fiber lasers as the primary choice for precision cutting stents. Selecting the right laser is critical to ensuring the highest quality stent cut, we would like to share the following background on how to choose the right laser for your stent cutting projects.

What is a stent?

In case you are new to the topic, a stent is a thin, flexible tube made of metal or polymer that is inserted into a blocked passageway, such as an artery, and inflated to keep it open. The stent acts as a barrier that pushes blockages like plaque against the passage’s walls to allow for the free flow of blood, or other fluids depending on the stent’s usage. Coronary stents are the most common type of stent.

how a coronary stent works

Advances in Stent Manufacturing

Coronary stents were granted FDA approval in 1987 and since then have come a long way. In the 1990s, stainless steel was the material of choice to create bare metal stents (BMS). Drug-eluting Stents (DES) were later introduced to combat potential side effects of early metallic stents. DES were coated with medication to prevent restenosis, a common side effect of Percutaneous Coronary Intervention (PCI).
Today, the majority of metal stents are made with cobalt-chromium because this alloy maintains its strength with a thinner strut. Polymer stents are also increasing in popularity because of their biocompatibility.

 

stent sample laser cut with ILT Versa stent cutting machine

Nitinol stent cut with ILT Versa laser system

Materials Used for Manufacturing Stents

Metals

  • 316 Stainless Steel (SS 316): Chromium, nickel and molybdenum alloy
  • Nitinol (NiFi): Nickel and titanium alloy
  • Magnesium (Mg) Alloys
  • Platinum Chromium Alloy

Polymers

  • Poly-L-lactide
  • Polycaprolactone

What are the Biggest Challenges in Stent Cutting?

Geometry

Stents come in many shapes and sizes depending on their usage. No matter the destined application, all stents have a complex geometry that require a precise cutting technique.

Material

Stents can be cut from a variety of different metal alloys and polymers. Each material poses a unique challenge for stent cutting. Manufacturers also have to consider biocompatibility.

Heat Damage

Laser cutting may have a minimal heat affected zone (HAZ), but manufacturers may need to account for additional processes to combat microcracks and other thermal damage that could occur with stent cutting.

Traceability

According to the FDA’s Title 21 CFR Part 11 requirements, manufacturers must maintain records of each step of the manufacturing process, including the cutting of stents.

Why are Fiber Lasers so Much More Effective in Stent Cutting?

High throughput, precision, wall-plug efficiency and repeatable results make fiber lasers the economical choice for stent cutting. Fiber lasers have a wider kerf, ideal for cutting spiral-patterned stents that require a kerf that is greater than 0.001” so the stent can flex correctly. Fiber lasers can also cut thicker walls with little taper.

Polymer and metal stents can be cut with hybrid femtosecond lasers. An ultrafast laser has extremely short pulse widths, which prevent heat damage when cutting stents. This in turn makes post-processing simple, using an ultrasonic bath and water instead of chemicals. Thin tubes with an outer diameter of 0.012” can be cut with a femtosecond laser without damaging the backside of the tube. Using an ultrafast laser provides users with unbeatable precision, offering a kerf of less than 0.0005”, which is ideal for sharp corners. While femtosecond lasers come at a higher cost, users may enjoy savings because ultrafast lasers require less argon gas.

Stent Cutting Precision with ILT Versa

For the better part of the past decade, the ILT Versa has earned the trust of stent manufactures across the globe. This fully-automated laser stent cutting machine provides the stability essential for high-precision stent cutting. Depending on your requirements, the ILT Versa can be equipped with an IR, green, UV, picosecond or femtosecond laser. 

technician cutting stents on ILT Versa - IPG's stent cutting laser system

Additionally, the Versa’s HMI-2200 software is Title 21 CFR Part 11 compliant, making it easier to adhere to the FDA’s requirements for record keeping. Its command center controls all parts of the stent manufacturing process, from directing the laser software to controlling support gasses. Operators can control all hardware and software components with a user-friendly interface. HMI-2200 not only makes operating the system a breeze, but also provides time-stamped traceable records with signatures. This stent cutting system also comes with a robust library of proven and validated subroutines developed over the past 20 years that can then be customized to meet a user’s specifications.

As your manufacturing processes scale, floorplans often shift. The ILT Versa is on wheels and its compact size allows the system to fit through standard doorways. This not only simplifies relocation, but also allows your team to avoid the time-consuming process of revalidation.

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