Medical devices benefit from laser manufacturing

20 Nov 2007

The use of lasers for manufacturing in the medical sector was the hot topic of discussion at a recent workshop organized by AILU.

The advantages of laser-based manufacture and advice on how to be successful in the medical sector were just two of the topics addressed in a one-day workshop organized by the Association of Laser Users.

With the total markets for medical technology now estimated at €180-260 bn, around 70 delegates gathered to hear how lasers can be used to manufacture a range of medical devices.

The morning included a talk from Alexander Knitsch of Trumpf, who provided a breakdown of the medical technology world market. "The market is dominated by the US, which makes up 43%, Europe (excluding Germany) makes up 20%, Germany 10% and Japan 11%," explained Knitsch. US companies also dominate the market with the top four companies: Johnson and Johnson, General Electric, Medtronic and Baxter enjoying the highest turnovers in 2006.

Neil Ball, CEO of Directed Light, followed with comprehensive advice on how to be successful in the medical sector. Among the issues touched upon were the difficulties in obtaining FDA approval and costly insurance concerns. "Protecting your IP and customer confidentiality is so important," explained Ball. "I have seen companies that have been sued out of business. I have also seen companies that do not maintain customer confidentiality, go out of business because customers no longer touch them."

He also discussed the importance of not overselling lasers as the solution to every customer's needs. "There are other competitors to lasers that will be around for a while, such as TIG welding, electron beam welding and water jet cutting," explained Ball. "So it is important to know the applications in which your technology excels."

The afternoon sessions saw several companies relate their experiences of using lasers to manufacture a variety of medical tools and equipment.

•Eduard Fassbind from SwissTec spoke about the need for improved quality and processes for stent manufacture. Stents are metal grid, tube-shaped structures used to stabilize weakened blood vessels. He explained that stents typically break after 3-5 years; therefore there is call for a higher degree of process control. A key element for achieving these aims is SwissTec's new diode-pumped fiber laser cutting system, which has a narrow laser focus of just 10-12 µm and a cutting speed of 500-600 mm/min.

•Alain Biernaux of Lasag discussed the possibilities of welding dissimilar metals using a pulsed Nd:YAG laser. He emphasized the importance of pulse shape in welding — for example, a rectangular-shaped pulse is used to reduce thermal problems at the start and end of each pulse. Continuing the theme of welding dissimilar materials, Birk Plönnigs of Jenoptik discussed the laser welding of plastic devices. Although Jenoptik is the largest producer of speed cameras in the UK, for the last few years the company has focused on the medical sector. In order to laser weld two different plastics together, Birk explained that the trick is to make one material laser absorbent and the other one transparent, which converts the laser energy into heat solely in the joint area for successful welding.

•Peter Dickinson from Spectrum Technologies discussed the advantages of using laser wire stripping instead of mechanical stripping. "Mechanical stripping can cause damage to the insulation and conductor, whereas laser wire stripping is not only more flexible but also causes less damage," commented Dickinson. The company has developed a 10 µm IR laser that vaporizes the insulator but is reflected by the conductor, which means no damage. For more difficult wire stripping, such as stripping the coiled wire that is used in pacemakers, the company has developed its own unique technique. "For coiled wire we use laser-generated plasma to envelope the insulator around the wire," explained Dickinson. "It is this plasma that actually strips the wire." This system is already in use with several world leading medical companies.

•The last talk of the day was given by Chris Ogden of Laser Lines, who discussed laser marking for the identification and traceability of medical devices. Laser marking can affect the material in ways that must be considered for any medical parts. The company has investigated a range of materials and the effects that laser marking can cause. "Structural/ chemical change, material removal or displacement can affect the function of the part," explained Ogden. "As can changes in corrosion resistance and discoloration of the material." The company concluded that high frequencies are key to the safer marking of these materials.