Portuguese industry was stagnant in the 1960s, 1970s and early 1980s, partly because of low investment in scientific research and new technologies. Any lasers that entered the country went mainly to university and public research institute researchers where they were used for scientific applications in physics and chemistry. Industrially oriented research appeared only in the early 1980s. Two different teams at the Physics Department of Porto University (Porto) studied laser physics and low-power laser applications. One focused on metrology and the other developed solid-state lasers for use in optical communications. In Lisbon, laser systems developed at LNETI, a governmental research institute, were used for the alignment of textile fibers and high-resolution internal inspection of bent tubes.
In the mid-1980s the Mechanical Engineering Department of Coimbra University and the Physics Department of Lisbon University conducted research in materials processing and surface modification using high-power lasers. Industrially sponsored work at Coimbra focused on the surface treatment of tool steels and cast iron, and continued when the group moved to Instituto Superior Técnico in Lisbon. The Lisbon University team was the first in the world to produce TiN hard coatings using laser CVD. In 1987 these groups joined to install the first high-power CO2 laser materials processing laboratory in Portugal.
The first industrial laser materials processing system, introduced in the early 1980s, was a diamond cutting machine based on a Q-switched Nd:YAG laser. It was installed at Dialap (Lisboa), a company cutting and polishing gem diamonds. In 1987, LNETI, together with the industrial company Efacec (Maia), developed prototype cutting and marking machines for the textile industry. The machines were based on slow axial flow domestically built CO2 lasers but were never commercialized.
Lasindústria (Lisboa), founded in 1989, was the first private company to deliver laser cutting services. Several other job shops were established within the next few years.
As industrial laser applications increased, several technological centers with competence in laser technology were established for the development of laser applications and technology transfer, supported by both Portuguese and European funds. Examples are IDIT, the Institute for Technological Development and Innovation, (S. Maria da Feira), and ITEC (Lisbon), a spin-off of the Laser Materials Processing Group of Instituto Superior Técnico. Both were devoted to laser materials processing, while INESC, the National Institute for System Engineering and Computers (Porto), focused mainly on optical communications.
Research activity
Today, groups in universities, research institutes and technological centers are engaged developing laser technology and diffusing it into industry.
The Laser Materials Processing Group of Instituto Superior Técnico (http://www..demat...ist..utl.pt/investigacao/.laser/.lasermat.html) focuses mainly on laser surface treatment and laser-assisted materials synthesis and design. The processing techniques investigated include laser alloying and cladding, laser freeform manufacturing, surface cleaning and microtexturing, and laser micromachining. These are applied to materials such as metal-matrix composites, aluminum alloys, superalloys, electronic ceramic-matrix composites, silicon, biomaterials and biological materials. Recent projects focus on the application of surface microtexturing to the control of cell adhesion and drug release activity in prosthetic materials, the use of computer-controlled variable powder feed rate laser cladding in the combinatorial design of metal-matrix composites and titanium-based biomaterials, and freeform manufacturing using metal/.ceramic functionally graded layers.
The Laser Surface Processing Group of the Physics Department of Lisbon University (http://www.lspl.fc.ul.pt/) is involved in research and development of laser-assisted microtechnologies, with early efforts focused on the growth of nitride, carbide and oxide ceramic thin films by CO2 laser CVD, to synthesize superhard coatings consisting of B-C-N ternary compounds. The interest in laser microprocessing has been extended to laser ablation of ceramic materials, using excimer lasers for the pulsed laser deposition of thin films and laser micromachining. Current work aims at growing ferromagnetic half-metallic oxides for application in spintronics.
INESC (http://www.inescporto.pt/.uk/defaultIE.asp) has been researching fiber lasers and fiber laser amplifiers. Some innovative designs of fiber lasers, CW and pulsed, have been developed. Besides this work, conventional lasers have been used as tools for device fabrication, laser deposition and characterization of materials, and optical pumping. This work led to the creation of a spin-off laser manufacturing company, JCP Photonics (Sunnyvale, CA).
Laser applications at INETI, a research and development institute within the Ministry of the Economy, are developed in the Optoelectronics Department (http://www.dop.ineti.pt/) and include prototypes of low-power laser systems for marking, cutting and engraving, which were licensed to the Portuguese company Servilog (Lisboa). High-speed (up to 20 m/s) laser cutting and welding of plastics has been studied and implemented under the sponsorship of a NATO project and the plastic processing machine has been patented. Other industrial applications, such as laser cleaning and rock drilling, are presently being investigated.
ISQ—Instituto de Soldadura e Qualidade (Oeiras) (http://www.isq.pt/.english/index.htm) is a service-oriented non-profit association founded in 1965 to meet the needs of the Portuguese metal working industries. With its range of CO2, Nd:YAG, excimer and diode laser facilities, ISQ has several years of experience in laser cutting, welding and marking, where its high-power lasers are used mainly in the automotive, metalworking, chemistry, textile, aerospace, microelectronics and cultural heritage industries. Lasers are also used for the welding of non-metallic materials and cleaning of artworks (paintings and stone).
IDIT, the Institute for Technological Development and Innovation (http://.www..idit.up.pt/zzzen/index2.html), located in S. Maria da Feira, a non-profit association for development, promotion and technology transfer to industry, is equipped with 6kW CO2 and 1kW Nd:YAG lasers and 3- and 5-axis CNC machines. Its activity is centered on offering laser materials processing services, consulting and training.
Lasers in industry
It is difficult to track the large number of industrial laser systems that are installed in a variety of industries for numerous applications.
Marking and engraving using CO2, Nd:YAG or excimer laser systems are currently being used to inscribe logos, images or product codes in a wide variety of commercial products, such as beer and soft-drink cans, plastic bottles, identification cards, driver's license cards, electronic components, small weapons, cutlery, eye glasses, electronic equipment, leather goods, hard metal tools and automotive parts. Complex shaped artistic objects in wood, plastic and metallic materials are also laser marked for decorative purposes, for gifts or advertising.
Laser cutting services are offered by many laser job shops—Imediata (Lisboa), Laser Fabril (Alfragide), Lasindüstria (Oeiras), NCP (Coimbra), Quantal (Argivai), S. Roque (S. Mateus Olveira), and Xanivor (Carambanxa), using 2D or 3D laser cutting equipment. Cutting of thin sheet metal parts and tubes are the main applications, but cutting of acrylic for advertising signs, cutting of plastics, wood and marble for decorative panels, cutting of wood for furniture manufacture, cutting of plywood die boards for the packaging industry and cutting of embroideries and textiles are also often performed.
A few laser job shops offer laser welding capability. To the authors' knowledge, laser welding is currently applied only in tantalum condenser manufacturing. Laser hardening and laser cladding for tool manufacturing and repair are being done as a service by several technological centers. Several tool repair shops using laser material deposition with manual wire feeding have opened during the last two years. We expect this application to grow further because a large plastic mold manufacturing industry exists in Portugal. The tool manufacturing industry, as well as automotive, telecommunications, home appliances, product engineering, and electronic equipment industries increasingly use rapid prototyping, and several machines have recently been purchased in this country.
The introduction of rapid prototyping in Portuguese industry has been stimulated by the creation of the publicly funded National Rapid Prototyping Network (http://www..uninova..pt/.rnpr/formation/en/). This network involves tool manufacturers, foundries, plastic molders and product engineering companies, as well as several R&D institutions and technological centers and aims at testing rapid prototyping technologies, training and dissemination of these techniques in Portugal. The network uses several laser-based processes such as stereolithography, layer object manufacturing, selective laser sintering of metals and selective laser sintering of plastics.
There are only a few equipment manufacturers integrating lasers in industrial systems. In materials processing, Adira (Porto) offers CO2 laser-cutting machines, and JCP Photonics Portugal (Sunnyvale, CA) has developed and is producing fiber lasers, aiming at the communications and military industries. The company currently has engineering and manufacturing facilities in both the U.S. and Europe.
Rui Vilar is with the Instituto Superior Téchnico in Lisbon. He can be contacted by e-mail at [email protected].