Medical Device Link.

Originally Published EMDM October 2003

Product Update

Lasers

Lasertec B.V.

A company offers two marking systems based on solid-state UV lasers. Developed by Lasertec B.V. (Barendrecht, Netherlands), the Fresco systems can be used in medical and pharmaceutical applications. One system uses the cold marking process, whereby a titanium dioxide pigment is photochemically changed to dark grey. Titanium dioxide is the most widely used whitening pigment in the polymer industry and is approved for use in many medical and pharmaceutical products. Products can be directly laser marked if there is approximately 1% titanium dioxide present. 

Lasertec’s other marking system is designed for use with transparent or translucent materials such as polypropylene, polyethylene, and polyester. When Micabs is added to these materials, thin films can be effectively marked without causing damage to the foil. The company also has developed a marking technology called Pixelstream that makes marking high-speed and high-quality greyscale images and logos possible.

Aerotech Inc. 

A compact high-performance ball-screw stage with a rigid base and brushless servomotor is suitable for laser machining applications. The ATS1000 from Aerotech Inc. (Pittsburgh, PA, USA) features a small cross section and medium payload capacity for precision applications. The tabletop unit uses stainless-steel helicoil inserts to protect mounting holes from thread wear. 

“The ATS1000 lends itself to the precise positioning required by the manufacturers of various medical devices,” says Ron Rekowski, director of product marketing at the supplier’s Advanced Automation Division. “The combination of accuracy, repeatability, and load-carrying capability makes it suitable for the laser welding, cutting, and hermetic sealing of medical devices, or the deposition of materials in DNA and drug research.”

For applications that expose the stage to debris, full bellows or way covers are available. The durable way covers protect both the precision-ground ball screw and linear guide bearing system over the entire travel cycle. An optional air-purge fitting allows air to be forced into the body of the stage. This creates positive pressure that further prevents particulates from entering the unit, making the product suitable for medical applications. According to Rekowski, “In proteomics or DNA applications, the sealed design protects the samples from potential contamination by particulates generated by the bearings and ball screw.” Sealed linear-motion guide bearings with integral wipers are incorporated to enhance payload capability and long life. The optional Halar factory calibration option further increases standard accuracy and repeatability. All ATS1000-series stages include Aerotech’s high-performance BMS-series brushless, slotless servomotor. 

Newport 

A refractive optical design and technology patented by IBM have made it possible to create a beam shaper with nearly 100% conversion efficiency. The refractive beam shaper from Newport (Irvine, CA, USA) converts Gaussian laser beam input to produce a collimated flat-top beam. 

“A Gaussian laser beam has always been something that scientists and engineers have had to put up with and work around,” says Tom Miller, Newport’s optics and optomechanics product line manager. “Now they can generate a uniform beam, allowing them to pursue a host of new applications with the precision and accuracy they require without significant losses in output power.”

The collimated flat-top beam can propagate over long distances without change in power and intensity or loss of uniformity. The shaper relies on low-dispersion refractive optics and produces no hard edges, speckles, or diffraction effects. Advantages over diffractive optics include wavelength insensitivity, collimated output, and simpler mounting and alignment. The beam shaper functions over a large bandwidth from far IR to deep UV, allowing for use in many fields. Applications include laser drilling and machining, and laser-based surgical instruments. 

Branson Ultrasonics Corp.

Infrared Assembly Method (IRAM) laser systems, developed by Branson Ultrasonics Corp. (Dietzenbach, Germany), are offered in two welding modes. The STTIr simultaneous systems illuminate the entire weld surface using laser diodes and fibre optics. A wide-beam scanning laser is suited for laminating or welding large surface areas and internal walls. 

Laser IRAM has certain advantages over alternative methods for welding plastics, notably weld quality, according to the firm. Because the process is noninvasive, the parts typically retain their cosmetic properties. Since there is no relative motion between the parts, only the weld area is heated and melted. In addition, by varying the power of the laser beam, it is possible to accurately control the power dissipation within the weld. The end result is minimal flash and no particulates, which are of particular importance in medical applications. 

Schober GmbH

A computer-controlled laser system is available for continuous in- and off-line processing in the device industry. Developed by Schober GmbH (Eberdingen, Germany), the unit can be used in both pulse-control and continuous operation. Compared with other contouring systems, the tools executing the contour are not subject to physical wear; no separate cutting tool is needed. The contour shape is created by a software program which can be stored for later use. Diffusion cooling technology and a catalyst integrated in the resonator result in high efficiency and flexibility. The beam is generated in a natural pipe arrangement and then is led to a scanner. The scanner has two mirrors that move independently. When both mirrors are moving, the 2-D contour is created. The firm’s equipment is suitable for cutting, perforating, welding, and marking of films, paper, cartons, self-adhesive materials, and multilayer papers. 

Canlas Laser Processing GmbH

Specializing in the production of precision laser processing equipment, a company offers microwelding and marking laser systems. The CPL 4000 from Canlas Laser Processing GmbH (Töplitz, Germany) allows microwelding with a spot diameter of only 50 µm. The equipment includes a Class I laser processing chamber. The laser beam is coupled with the path of rays of a stereomicroscope, enabling coaxial observation. The CPL-CL50 laser marking system marks refined steel by means of a unique process without any engraving effects. In contrast to an engraved part, the treated surface remains smooth and can be steam sterilized, making the system suitable for the production of precision medical instruments. 

Rofin Baasel Lasertech

A fully equipped laser system can cut stents and tubular material in almost any geometric pattern. The StarCut 18 laser from Rofin Baasel Lasertech (Starnberg, Germany) can easily be changed from fundamental to low-order modes of operation at frequencies up to 3000 Hz. Kerf widths of less than 20 µm are routinely achieved. The system is equipped with an automatic feeding system that accepts tubing of any length. Easy-to-use software converts .dxf or .dwg files into the NC code. A graphical display of the cut geometry is displayed on the CNC monitor and allows process verification prior to cutting. 

Laser cuts are done in dry mode without the use of fluid inside the tube material. The cutting nozzle in combination with a stereomicroscope and optional camera facilitates setup of the system to individual tubing diameters. Nearly any metal material can be cut. 

Lasag AG

A welding process developed by the Swatch group partners and the Fraunhofer Institute of Laser Technology in Aachen, Germany, was demonstrated by Lasag AG (Thun, Switzerland) at the Laser 2003 show in München. Lasag’s FLS 542C laser operating with a high-speed galvo scanner joined a 7-mm-diam post to a disc. A circular 21-mm-long seam was welded in 50 milliseconds with constant local intensity. The welding depth was 0.3 mm. 

Besides the short welding time for contour lines, the Shadow (stepless high-speed accurate and discrete one-pulse welding) process offers several other advantages. The technique enables nickel alloy and stainless steel with a thickness of 0.025 mm to be welded using less than half of the energy required by traditional laser welding. A real-time power supply enhances the system’s efficiency at peak power applications. 

The FLS 542C covers a working range of up to 500 W. It is available with up to six fibre outputs and has pulse-forming and pulse-on-demand capabilities. Other features include a completely sealed power supply with active water cooling, multiple interfaces for easy integration, and a modem for remote operation and diagnostics. 

Ruetschi Technology

Developed and designed specifically for 3-D laser welding applications, a six-axis robot can be used either as a manual workstation or automated system. All relevant robot and peripheral parameters can be entered and managed via a user-friendly graphic interface linked to a rugged industrial personal computer. The Epoc 900 from Ruetschi Technology (Muntelier, Switzerland) has a repetition accuracy of ±0.01 mm and a trace accuracy of ±0.02 mm on a working area of 300 ¥ 300 m. Depending on the application and welding task, different laser sources and beam delivery systems can be integrated. The Epoc 900 can be used to weld a variety of metal parts including distractors for jaw surgery and torque wrenches that tighten set screws for pacemaker leads. 

Leister Lasersystems 

Hot-air welding systems enable the low-cost mass production of microfluidic packaging and plastic disposable devices. Mask welding, a patented process developed by Leister Lasersystems (Sarnen, Switzerland), a division of Leister Process Technologies, can bond microconstructed components rapidly and reliably. These devices are usually manufactured in silicon and capped with glass. The seal is created with epoxy materials. “The mask welding process uses plastics for these devices and obtains these intricate seals by creating weld areas as small as 100 µm,” says Marcel Pironato, sales manager at Leister. “No adhesives are used, thereby eliminating the risk of contamination from the epoxy,” he adds. Additionally, the volume of the chambers being sealed remains fixed, as the parts do not collapse during bonding. The thermal stress on the components remains extremely low. 

Spectra-Physics

One of the more novel items exhibited at the Laser 2003 trade show in München was a sealed bottle of Kentucky whiskey bearing an elaborate logo marked on the inside of the glass. The logo was created by Spectra-Physics (Mountain View, CA, USA) from a simple CAD/CAM file using a solid-state 335-nm laser. The cold marking process causes no damage to the inner or outer surfaces. The nature and quality of the bottle’s contents also remain unaltered. 

The UV laser reportedly can mark glass with much higher spatial resolution than an IR laser can. According to Gerd Esser, acting director of the Bavarian Laser Center, UV-laser glass marking has applications in many industries. “One example is flat-panel displays, where it is important to mark the panels and parts with serial numbers,” he says. “Surface marking or engraving would be undesirable in that application, because of the contamination risk.”
The method has also been used to mark tiny 2-D matrix codes inside 0.7-mm-thick microscope slides, leaving both outer surfaces untouched. 

CPR Automation Ltd.

Transmission laser welding has been developed by a company to optimize volume production. CPR Automation Ltd. (Tamworth, Staffs, UK), a manufacturer of assembly machines, designed a machine that produces up to 4 million welded assemblies a year. The four-station rotary machine has a laser mounted at Station 2 on a Yamaha x–y Cartesian robot. A leak test sited at Station 3 provides quality assurance. The main advantage of this process is the absence of a catalyst. “The different colours required by our system avoid the application of a catalyst,” says John Fowkes, managing director. “The main advantage is therefore cost and ease of use,” he adds. Also, the absence of a catalyst ensures a contamination-free process, which is suitable for electronic and medical applications. 

Tri-Star Technologies 

A marking system provides permanent, tamper-proof marking for pharmaceutical products and medical device components. The M-100L-M series of cold lasers by Tri-Star Technologies (El Segundo, CA, USA) can safely and easily mark tablets or capsules even after they have been blister packaged. The system provides permanent identification without damaging the product or the packaging. It can also be used to indelibly mark plastics, resins, glass, valves, connectors, and other components of medical devices. The cold laser can mark either the inner or outer surface without damaging very thin or thermally sensitive substrates.

“The cold laser offers drug packagers added security by eliminating the possibility of tampering with packaged drugs,” says Tri-Star president Alex Kerner. “Since the tablet or capsule is marked after being sealed in blister packs, substitutions are not possible,” he adds. The fully automatic, computer-controlled high-speed UV laser marker may be easily integrated with existing equipment. 

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