Most medical devices, especially reusable ones, are made of some type of stainless steel. Laser cutting technology for these stainless steels has been widely known and widely used. Fiber laser with nanosecond pulse is the main choice for manufacturing stainless steel products, because these lasers can provide faster speed and higher throughput. Femtosecond (fs) lasers are only used to cut very thin sea wave tubes, components with delicate details, or applications requiring the excellent edge quality provided by such lasers.
 

Cutting other "niche" metals used in medical device manufacturing (MDM) often poses different challenges, but the versatility of laser cutting almost always provides excellent solutions. Let's see how/why metal laser cutting can be applied to three completely different metal types: magnesium, nickel-titanium alloy and platinum (as well as gold).

Femtosecond laser cutting of magnesium support

In the United States alone, more than 2 million stents are implanted into patients every year. Laser cutting, especially femtosecond laser cutting, is the ideal choice for manufacturing these supports, because it can easily provide the required edge quality and greatly reduce the need for mechanical or chemical post-processing. It is also important that fully integrated automatic machines simplify the 3D cutting of tubular blanks. These machines support wet cutting, which helps ensure that the back wall will not suffer thermal damage when cutting very thin pipes.

Because the stent site may sometimes re-form blocks and cause vascular obstruction, resulting in restenosis, in recent years, the application of bioabsorbable stents to solve this problem has become more and more widespread. The earliest bioabsorbable scaffold was made of organic substances such as polylactic acid (PLLA). At first, green picosecond laser was used, but the result was not ideal. Therefore, femtosecond laser was quickly adopted and became the de facto standard. After that, researchers developed absorbable metal (magnesium) stent as another alternative material. The thermal characteristics of magnesium mean that the fiber laser processing will produce an unusual problem, that is, the cutting surface will produce small metal droplets. These droplets need to be removed by mechanical cleaning. However, this may damage the thin columns required in many support designs; This post-treatment may result in a yield of only 50%. Therefore, femtosecond laser has become the standard cutting technology again.

Fiber Laser Cutting of Ni-Ti Alloy

Nickel-titanium alloy or "memory metal" has special properties such as superelasticity and shape memory. These characteristics make it have certain advantages, which can be used in some different implantable instruments and surgery, including TAVR.

At present, most of its nickel-titanium alloy tubular products are within the range of 3-6 mm in diameter. Fiber laser cutting can provide them with good throughput and edge quality at the same time. Cutting accuracy is a problem to be considered when selecting machines with high stability and repeatability.

Erosion cutting of platinum

In most of today's medical device manufacturing applications, the ideal laser cutting methods are usually fiber laser cutting and femtosecond laser cutting. However, a few manufacturers use a new process called "erosion cutting" instead. The company uses this technology as a low-cost alternative to femtosecond laser cutting to manufacture products including medical and biotechnology applications and platinum-based components used in fuel cells.

"The traditional cutting method is not suitable for thin parts, because there is too much heat generated around and it can not support tiny structures weighing only a few grams. Erosion cutting can avoid these problems." Erosion cutting uses the fast galvanometer scanning technology that is usually used for marking. In fact, the initial use is a 20 W fiber laser, which is a system that is more often used to complete marking/engraving operations.

"Erosion cutting is not only using one pass of focused laser to cut, but at least including dozens, sometimes even thousands of repeated lasers, ablating several microns of material at a time. But thanks to high-speed galvanometers, up to thousands of operations can be completed in a few minutes. This unique technology is actually applicable to almost any metal and other harder materials (such as ceramics)"

About HGTECH: HGTECH is the pioneer and leader of laser industrial application in China, and the authoritative provider of global laser processing solutions. We have comprehensively arranged laser intelligent machine, measurement and automation production lines, and smart factory construction to provide overall solutions for intelligent manufacturing.