Medical Device Link.

Originally Published EMDM September 2005

Industry News

Spiral drilling technology developed by the Fraunhofer Institute for Laser Technology can produce holes with diameters ranging from 30 to 300 µm.

Industrial lasers continue to spearhead advances in cutting, drilling, marking, and related operations. Because laser-based machining and marking is a relatively clean, contact-free technique that causes minimal, if any, damage to the material being processed, it presents significant benefits for medical device OEMs. Recent technological advances in the photonics arena were showcased at this year’s Laser 2005 show in Munich in June. Here are some of the products that caught our attention.

Specializing in the design and manufacture of low- and medium-power high-voltage convertors, Systems Development & Solutions (SDS; Saint-Maur-des-Fossés, France) showcased its line of ultraminiature dc modules at Laser 2005. The systems provide a reliable supply of stable high voltage with low ripple, and are suited for use in research and industrial applications. The firm claims to be one of a handful of companies in the world to offer these products.

The devices regulate voltages by means of an external potentiometer or analogue input signal. The electrical input voltage can be set at 12, 15, or 24 V, as required; output voltages range from 200 V to 4 kV, at a maximum output of 4 W. The compact modules can be mounted vertically or horizontally, making them suitable for any number of applications.
“Our miniature convertors are primarily intended for use in electron microscopy, photomultiplier tubes, or so-called multichannel plates,” says export sales manager Paul-Etienne Reiss. They can be supplied in standard or custom configurations for OEM integration.

The firm also develops larger modules that can provide extremely fast high-voltage bursts for use in laser systems and mass spectroscopy and beam-deflection applications. They are designed for a range of applications in which rapid commutation is desirable. A range of high-voltage supply modules suited for medical equipment is available.

Innovations in Microdrilling

When it comes to material processing, laser systems are synonymous with precision and flexibility. The new PP range of Innoslab diode-pumped lasers from Edgewave GmbH (Würselen, Germany) carries on this tradition, notably in microdrilling applications. The firm introduced the line at Laser 2005.

The laser technology is based on what the company calls the “slab” concept. A lamellar laser crystal—the slab—is activated by means of a simple laser-diode stack construction. The laser beam is extracted by a hybrid resonator from the pumped volume, producing a very focused beam. Consequently, the system is suited for a range of applications from plasma generation to microdrilling, cutting, structuring, cleaning, polishing, and engraving. Precise microdrilling operations with freely defined shaft characteristics can be achieved in glass. The cross sections can be variably adjusted, as can longitudinal aspects. This capability is particularly interesting for medical technology companies and manufacturers of analytical instruments. Furthermore, the laser can be used to engrave markings on the inner surfaces of transparent materials.

The air-cooled lasers are sufficiently compact for easy integration into production processes. They deliver up to 30 W average power, and feature up to 1 mW maximum pulse power and up to 50 kHz pulse frequencies.

Similar applications were a centerpiece at the stand of the Fraunhofer Institute for Laser Technology (ILT; Aachen, Germany). Conventional machining methods may be ill-suited for the production of miniature implants and tooling with part dimensions below 20 µm, according to ILT. The firm has developed a compact spiral-drilling technology that can be integrated into laser systems for use in applications that require precise and flexible microdrilling.

The technique involves repeatedly displacing the laser beam in a rotary movement over the workpiece to ablate the material. “The laser beam is directed through a revolving image rotator,” explains ILT director Reinhart Poprawe. "This rotator is integrated into a hollow-shaft motor, which produces the high-speed rotation."

Holes with diameters ranging from 30 to 300 µm can be drilled using this technique. By slanting the laser beam, tapered holes with a 1:2 expansion ratio can be produced. The technology is suited for the manufacture of microdosing systems, among other medical applications.

Another R&D organization exhibiting at Laser 2005 touted a technology for defect-free processing of nonmetallic materials. Developed by the Center of Advanced European Studies and Research (CAESAR; Bonn, Germany), the technology enables the precise cutting, drilling, structuring, and engraving of plastics, rubber, synthetic fibres and fabrics such as Kevlar, carbon, composites, ceramics, natural materials, cellulose-based materials, and easily deformable components. The method allows rapid processing with minimal thermal modification of cut edges. Three-dimensional processing is also possible. It will not damage the optical properties of transparent materials such as PMMA, and components made from very fragile materials can be processed at a dimensional accuracy of 100 µm. CAESAR’s holography and laser group “adapts its technology to the needs of its industrial clients based on the material being processed and the project goals,” says Francis Hugenroth from the firm. “The group provides feasibility studies, process and system development, as well as a range of laser material-processing services,” she adds.

The research centre envisions that the technology may be used in the future to cut through bones. Cutting geometries can be freely defined by the user, and the system can ablate bones and cartilage without inducing thermal damage or generating bone and metal debris. The system can perform fine incisions measuring 2 mm wide and up to 7 mm deep.

CAESAR also demonstrated an innovative holographic system for three-dimensional facial scanning at the show. Initially designed to assist plastic surgeons, the system uses short laser pulses to create a hologram of the patient’s face. This 3-D model, which can be displayed on any computer screen, reveals both the bone structure of the face and the surface soft tissue. The high-resolution scan even visualizes pores and fine hairs, and it can be rotated and sized at will. The first mobile holographic camera system is currently undergoing clinical tests at the Clinic for Reconstructive Surgery located at the university hospital in Basel, Switzerland.

Contact Information

Systems Development & Solutions, 5 boulevard de Créteil, 94100 Saint-Maur-des-Fossés, France; phone: +33 1 43976504; fax: +33 1 48858270; Internet: www.sdshv.com.

Edgewave GmbH, Schumanstr. 18 B, 52146 Würselen, Germany; phone: +49 2405 41860; fax: +49 2405 418633; Internet: www.edge-wave.com.

Fraunhofer Institute for Laser Technology, Steinbachstr. 15, 52074 Aachen, Germany; phone: +49 241 89060; fax: +49 241 8906121; Internet: www.ilt.fraunhofer.de.

Center of Advanced European Studies and Research, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany; phone: +49 228 96560; fax: +49 228 9656111; Internet: www.caesar.de.

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