Originally Published MPMN November 2001

EQUIPMENT NEWS: Laser Processing

CO₂ and UV Laser Systems Accurately Cut Complex Shapes

Systems are quick, versatile, and easy to use

Laser welding, cutting, and marking systems offer a number of features that make them suitable for medical device manufacturing applications. New systems that meet the stringent demands of the industry are discussed in this section. For example, two roll- and sheet-fed systems using either a CO₂ or UV laser source can process a variety of materials. Other products presented include a diode-pumped solid-state module that provides 750 W of power at 1064 nm, a pulsed Nd:YAG laser with a variety of power output options, and a compact, portable excimer laser system.

Two turnkey, beam-steered galvo laser systems from Preco Industries are designed for excising and ablating polymers, adhesives, and polyamides. Both systems cut complex shapes while maintaining a high level of accuracy. They perform the same functions as a typical die-cutting press, but without the turnaround time and expense of traditional hard tooling.

The PLG-15 is a sealed high-speed CO₂ laser system that achieves speeds up to 40 in./sec. It is designed for cutting, ablating, marking, and drilling intricate geometries in a variety of materials including plastics, adhesives, ceramic, and glass. The system is capable of clean cutting polyamide materials with no carbon residue. Applications include processing of flex circuits, membrane switches, graphic overlays, gaskets, and labels. The machine features a working area of 20 x 20 in.

The PL355-15 is a solid-state diode-pumped UV laser system for excising, micromachining, and ablating thin metallic foils, polyamides, and other nonmetallic materials. It can excise and trim polyamide flexible circuits from base matrices without burning or leaving carbon residue on the parts or substrate. The short-wavelength laser operates in a photo-ablative process that can cleanly cut and kiss-cut polyamide base materials, copper circuit traces, and other conductive films and inks with no photo masks or hazardous gases.

The PLG-15 and PL355-15 have an accuracy and repeatability of ±0.004 and ±0.001 in., respectively, depending on the field size. CCD x-y-theta registration enables scaling based on fiducials. As the material stretches or shrinks during processing, laser geometry can be scaled in relation to actual fiducial separations. The systems come standard with a manual sheet feed tray. Options include an automatic conveyor system and a semiautomatic, rotary indexing, load-unload station. An optional web-handling system provides unwind and rewind of the substrate and matrix stripping and rewind for the scrap. The Windows NT-based touch screen controls facilitate setup and operation, and a job-memory storage function allows quick repeat setups.

End-pumped single-mode laser offers high beam quality with short pulse lengths

A short-pulse laser marker operates in a high brightness mode, making it suitable for applications involving metals, plastics, ceramics, and other composite metals. The PowerLine E from Rofin-Baasel Inc. is capable of sophisticated operations such as photo-quality marking. It features a small footprint for easy integration into a variety of new or existing machine concepts. Standard operating features available in the Windows-based VLM software allow different intensities from pulse to pulse for marking gray-scale bitmaps. The system's diode technology is designed for long life and minimal maintenance. Its cabinetry is IP54 compliant for use in industrial environments without concerns over long-term environmental degradation of its performance. The resonator measures 45 cm in length, and the unit offers a high peak power for short marking time.

Diode-pumped solid-state module can be incorporated into new or existing laser systems

A continuous-wave diode-pumped solid-state module is designed to provide reliability and efficiency when incorporated into industrial and scientific laser systems. The RG-series pump module from Cutting Edge Optronics Inc. can deliver more than 750 W of continuous-wave power at 1064 nm. It is suited to serve as the core of a multikilowatt laser system. The laser module head pumps an Nd:YAG laser rod by radial arrays of coupled, long-lifetime laser diode bars to deliver pump uniformity and stable lensing performance. It is cooled by recirculating filtered water from a simple chiller system.

Pulsed Nd:YAG lasers enable controlled precision welding

A line of pulsed Nd:YAG lasers was designed specifically to meet the demands of precision welding of medical devices. Available from Unitek Miyachi Corp., the A-series lasers offer a 5-70-W average output and branch balance stability. They feature power ramp-up and ramp-down tapering that improves seam welding quality by preventing under- and overheating at the beginning and end portions of the seam.

Real-time power feedback ensures pulse-to-pulse energy stability. Laser pulses are programmed in peak watts or joules that automatically compensate for flashlamp degradation, temperature variations, and power changes.

Pulse shaping, ordinarily only available in higher-power models, optimizes welding schedules for a variety of materials and produces deep penetration welds with low splatter. It also helps to eliminate cracking in otherwise difficult-to-weld materials. With up to 20 programmable segments, including steps and ramps, the lasers provide flexibility in tailoring the weld pulse to meet a variety of process requirements and extend the range of materials, platings, and joint designs that can be successfully welded.

The A-series 5-, 15-, and 25-W models are air cooled and feature up to three shared energy or time outputs. The 50- and 70-W models are capable of 50- and 70-J pulses, respectively. They are water cooled as standard, but can be ordered with an air-cooling kit that allows operation at reduced average power levels. The 50- and 70-W models can be configured with up to four shared energy outputs, up to six shared time outputs, or a combination of time and energy output configurations, allowing one laser to support multiple weld workstations.

Laser marker combines stable power with high-resolution graphics capabilities

An updated diode-pumped laser system incorporates a 10-W Nd:YVO₄ laser source while maintaining high-resolution graphics capabilities. The LE-100S from RMI Laser Division includes a sealed laser head that uses fewer critical components than previous models for more efficiency and reliability. The pump diode can provide stable power for up to 10,000 hours, eliminating the need for costly and time-consuming lamp replacement. The system is powered by a standard 110-V-ac wall plug without an external heat exchanger. SymbolWriter software can convert most scanned images or Windows-based graphics into clear marked images on a range of materials. Many traditional bar codes and 2-D machine-readable codes are also supported. A microprocessor-based controller provides automatic system diagnostics and a built-in interface that enables the laser to be remotely operated from an industrial terminal or PC-based computer. Applications include marking texts, graphics, bar codes, and data matrices on various metals and plastics.

Laser production system incorporates CO₂ and Nd:YAG laser formats

A new laser system is suited for engraving and cutting machines. The SL-4848 Combo system, offered by Online Inc., can be provided with a CO₂ and an Nd:YAG laser for processing a wide variety of materials. Along with integrated CNC-type control, the system features a simple property window that allows the user to set speeds, laser power, gas assist, and offsets for quick changeover when running different types of material. The 48 x 48-in. table is elevated with four leadscrews and 1½-in.-diam hardened shafting for stable, precise control and automatic focus adjustment. The SL-4848 features machine-tool quality construction including hardened ground rails and brushless programmable motors that are mounted on a rigid box frame construction and fastened to a heavy-duty welded tubular steel base. The automated sloped front opening provides easy access from the front or top. An integrated vacuum-fume extraction table is equipped with four individual shut-off valves for disabling any combination of sections when they are not required. The embedded control system does not require a PC for programming or operation. Additional inputs and outputs are included for controlling peripheral equipment such as conveyors and rotary dials without the use of an external PLC.

Compact excimer laser is portable, yet powerful

A self-contained excimer laser is available in 157-, 193-, 248-, 308-, and 351-nm wavelengths. The Optex from Lambda Physik Inc. has a 60 x 40 x 30-cm footprint, offers up to 22 mJ per pulse, and provides an up to 200-Hz repetition rate. It is designed to achieve precise results in a range of processes in clinical, laboratory, field, and factory settings. Application areas include dermatology, ophthalmology, photochemistry, and surface analysis. The laser is suitable for micromachining and microstructuring. It features Windows-based software, air cooling, single-phase connection, and the choice between serial RS-232 and DLL interfaces for 16- and 32-bit applications. Options include fiber-optic coupling and an application-programming interface. The company's NovaTube technology reduces component corrosion and contamination. Gas and tube lifetimes are increased while operating costs, downtime, and maintenance are reduced.

Katherine Sweeny

Copyright ©2001 Medical Product Manufacturing News