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TECHNOLOGY SAFETY


your eyesight will be destroyed in a fraction of a second. It is important that people get the right level of safety.’


Trumpf’s latest enclosure has reflective and laser absorbing materials. Image courtesy of Trumpf


➤ Another addition related to tackling the challenge of securing solid state laser beams with mechanical roof tops or shutters is the use of materials that absorb the energy from the solid state laser. ‘We started combining materials and now we know ways that are not working but we also know which are working. With this combination the entire roof of the enclosure is equipped and covered,’ Kohlloeffel tells Electro Optics.


In the enclosure the sides


are reflective, guiding the laser radiation to the top, while the roof has an absorber to reduce the laser power dramatically to below the limits set by law.


Another safety measure is ensuring that any operator that steps on the machine’s table is not struck directly by laser radiation. For this problem Trumpf installed two laser scanners, located two metres above the floor. If someone is scanned in this area at a height above two metres inside the TruLaserCell while the laser is on and processing on the other side the machine stops automatically. Trumpf’s latest development for machines with solid state lasers is the TruLaserCell 7040. It has been commercially available from the second quarter of 2011. One of Trumpf’s customers received it in January 2011 for testing. It is using the system in the dual station mode with its 3kW solid state laser from Trumpf, in a three shift operation.


Any operator will also wear


protective eyewear. Lasermet is a distributor of laser safety eyewear in Europe. ‘We have been providing the optimum solution for eyewear for many years – to the appropriate standard – by sourcing from several manufacturers,’ says Tozer. Laser Components also distributes eyewear. Its Bernhard


A lot of eyewear is designed for a range of wavelengths. Some will filter out 780-840nm, others 315 to 400nm and then there are those that filter 800 to 950nm and above. The glasses with the wider range, from 700nm up to 1100nm have darker filters. ‘The more blocking you put on, the more the visibility is reduced. So instead of 50 per cent plus visibility you get 17 or 18 per cent,’ explains Russell. ‘Safety levels are creeping up now. Whereas before there was just a level of five, that is now six or seven. We are also finding [levels of] eight and [some products], one or two, at nine.’ Another aspect to eyewear design that arises when providing the greater protection needed with Class 4 lasers is the use of


People keep glasses longer than they


should... scratches, even on a £400 pair, mean the eyewear is giving less protection


Russell spoke to Electro Optics about the pros and cons of eyewear selection and use. ‘I used to replace my [safety] glasses every six months, they have a polymer frame and they get thrown on benches. The scratches thin the filter and it might still be eye safe but it is taking that risk, you’re thinning the material,’ he explains. ‘With Class 4 [lasers] your reactions aren’t quick enough and


glass. ‘With CO2 [lasers] you will


end up with glass filters in them. But unfortunately glass makes them very, very heavy. A lot of people don’t like that. When you’re looking down at something you need something that is very sturdy, and they don’t tend to be very comfortable’. Because of this, companies have been trying to reduce the weight. ‘We have found a trend in people wanting


lighter, more comfortable eyewear. We have started seeing changes; where you could only find glass we’re now finding there is a polymer equivalent,’ Russell says. ‘Something polymer, a lighter [lens], if you’re wearing them all day it will make a big, big difference to your work’. Russell explained that a lot of the new developments in eyewear have been developing technology to get away from glass but that ‘in certain circumstances you’ll never get away from glass’. Russell has seen product changes over the last 10-15 years with glasses that were uncomfortable and bulky and heavy for a high level of protection are now becoming sleeker and more ‘wrap around’ in style. ‘We have several ranges ideal for people with prescription lenses,’ he adds.


Users have also demanded better visibility and there is a much wider range of clear options where there is a visibility of 90 per cent but still giving the blocking at the wavelength users need. Prices for basic glasses through to the sleeker wrap around styles range from £25 to £300-£400. Russell warns that people keep glasses longer than they should and that scratches, even on a £400 pair, mean the eyewear is giving the users less protection than it should. ‘If you have a cluster of scratches then replace it immediately, it is not worth taking the risk. [But] safety glasses should be the last line of defence. There should be other safety measures in place,’ including the enclosures. l


Polymers mean glasses can become lighter. Image courtesy of Laser Components


24 ELECTRO OPTICS l FEBRUARY 2012


Some applications will still require heavy glass eyewear for protection. Image courtesy of Laser Components


www.electrooptics.com


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