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Laser light for a mining train

Equipment from a small company controls the wagons of the Rio Doce

Five small orange colored boxes installed along the railway lines of the Company Vale do Rio Doce in the State of Espírito Santo, make up part of the newest system for the exact positioning of the wagons which must be tipped for the unloading of iron ore. The boxes are laser distance gauges that guarantee a greater precision in the stopping position of the wagons and substitute men in an inhospitable job exacerbated by the high degree of suspended particles at the location. With this, Vale is the only company of its kind in the world to adopt such a system.

The innovation was developed by Opto Eletrônica, a company from São Carlos that had financial backing from FAPESP, within the Small Business Innovation  Research  Program (PIPE). In total R$ 23,200 was invested up until the month of September when this project – named Laser Distance Gauge of 20 meters Range for Industrial Use – will be finalized.

This gauge works like a radar, informing the distance between the emitter and the target. The difference is that, instead of using radio waves, the equipment uses a luminous signal produced by a laser beam. The first prototype of the gauge was ready in November 1998 and the manufacturing in series is expected to begin by the end of this year. According to the project’s coordinator, engineer Mário Antônio Stefani, the specification by Vale made Opto modify the industrial format previously imagined for the apparatus. The gauge was adapted to gain greater physical resistance and to function in inhospitable environments such as the transportation of iron ore. To this end, the box received a special steel plating and it is even rain proof.

“The main obstacles which impeded the correct working of the sensor are being overcome”,  says Stefani. As an example, there was the excess dust present in the area because of the movement of the iron ore in the wagons. Each wagon has a capacity of carrying up to 90 tons. At the beginning, the dust clouds interfered with the reading of the laser, which showed high “sensibility” to overcome the denser ones. “We did every adjustment necessary for the laser sensor to work in the exact conditions of these hostile environment”,  says Stefani.

This version will have considerable use in other applications, such as measuring the position and the length of iron ingots in steel works, checking on the volume of seeds and grains in general in silos, trucks and wagons, and to measure the length and width of timber in sawmills. The manufacturing of a portable gauge is forecast, one that could widen the use of this apparatus, in the civil construction  and architecture markets. This portable equipment could also be used as a sensor for positioning robots in industrial production lines.

The challenge presented to Opto by the Vale do Rio Doce company was to overcome the limits of the range of action encountered in other types of gauges existing on the market, which extend in the maximum to 50 centimeters. At the Vale installation, the loaded wagons circulate normally around two meters from the location where it is possible to install a gauge. The distance, however, can be as large as 7 meters. The apparatus is connected to a hydraulic arm which pulls the wagon, driven by a motor of 800 HP, equivalent to the force of the motors of ten popular 1.0 cars. Within the parameters established by Opto’s client were centimeter precision, response time of the laser sensor to be at the maximum one twentieth of a second and a laser beam with a maximum power of 5 milliwatts. “The power limit is an imposition by international security standards”, says  Stefani.

Fast growth
Unexpected challenges have marked the history of Opto Eletrônica. Born in 1985, the company was the only one to make in Brazil helium-neon laser emitters, a type of product in clear growth at that time in the United States. It is equipment that had multiple applications in medicine and related areas, such as photo coagulators, scalpels moved by laser, among others. It was not a product sold directly to the consumer. Opto made the laser emitter and not the final product.

Over time the company realized that in the Brazilian market there was a lack of final products with clear laser use. “In Brazil, at that time, there were almost no applications”,  recalls Jarbas Caiado de Castro, one of the company’s partners. Consequently,  Opto began to develop complete sets of equipment for direct sale to the consumer, reaching a total of 100 types of product based on the laser. The company grew considerably until the end of the 80s, leaping from 6 to 70 employees.

However, in 1989, a new type of emitter was launched in the United States, this time activated by semiconductor diodes. These components are more efficient, cheaper and occupy less space than the gases and mirrors used in helium – neon technology. “It was more or less the same as changing from the valve to the transistor”, compares Castro. Thus, from one moment to the next the laser made by Opto was no longer a rival for the new competitor. Extreme and fast measures were taken, such as the adoption of the new component.

It was a correct decision and the growth of the company was large and swift. Opto began the year 2000 with 100 employees and yearly sales in the order of R$13 million. Today the line of products of Opto goes from ophthalmological microscopes of very high definition, to photo coagulators, to lasers for surgery on the retina, as well as precision systems of the images of the eye, making it possible to execute the coagulation of micro fissures in this organ. One can add to this other innumerable equipment of industrial use. “We are the pioneers in the production of industrial laser equipment in Brazil”, emphasizes  Castro. “We are in a segment which has an annual turnover, world wide, of more than US$ 100 million. We hope to grow at more or less 20% this year”, he says.

Light reflections
Opto has six partners and is structured into three divisions. The first is  basic, dedicated to research and development. The second looks after the manufacturing of laser implements and optical precision components. The third is directed towards the production of fine films used in reflectors of “cold light’ another niche of the market which is very promising. In this area, Opto is already the major national producer of odontological reflectors. “We are exporting 45% of our production”, adds Castro.

Products of this type frequently bring on new industrial segments, which means the creation of a more qualified workforce. At Opto the employees have a profile which runs from technicians with high school education to engineers with masters and doctorates, as well as the 20 permanent sales staff. “In this sector it is not possible to keep generic, out of touch sales staff”, explains Castro. The specifications and applications demand an understanding of innumerable details that only the person who specializes will be able to understand. This is exactly the path which Opto wants to follow, incorporating knowledge into its products.

Mário Antônio Stefani, electrical and mechanical engineer, graduate from the São Carlos Engineering School of the University of São Paulo (EESC-USP). He took his masters and doctorate at the Physics Institute of São Carlos (USP).
Jarbas Caiado de Castro, physics graduate of the Physics Institute of São Carlos (USP), where he also took his masters and is presently an incumbent professor. He has his doctorate from the Massachusetts Institute of Technology (MIT), in the United States.

Distance Laser Gauge with Range of  20 meters for Industrial Usage (nº 97/06877-7); Modality Research Awards – PIPE; Coordinator Mário Antônio StefaniInvestiment R$ 233.221,00