A vision of useful, timely feedback

Dean Palmer talks to the director of the UK Industrial Vision Association about how companies are using vision systems and where he thinks future vision technology is going "The best thing about employing a vision system is that you start to learn more about the manufacturing process you are using it with. You get timely, chronological feedback from the system," said Don Braggins, director of the UK Industrial Vision Association (UKIVA). He continued: "Vision systems are not new to the manufacturing industry. Even as far back as 1990, vision technology was being employed by the automotive industry. Rover's Cowley plant, for example, had three line installations, where vision systems were being used to inspect the dimensions of car body panels. The technology ensured that the panels were positioned correctly in relation to the seam welding robots." And, according to Braggins, the auto industry today is still using vision systems in a big way, but it's the lower Tier suppliers that are now having to employ the technology to satisfy the car manufacturers and OEMs that assemblies and parts are being manufactured to stringent quality standards. Other industries are getting in on the act too. Braggins cited the example of a company in Bristol that manufactures ceramic tiles and uses vision systems to inspect the surface of the tiles for defects. Other more obvious applications of industrial vision systems include electronics assembly, semiconductor manufacturing and for inspecting printed circuit boards. Braggins continued: "With vision systems in the mid-19990s, customers were asking whether vision suppliers could actually provide a system that could do the job successfully. Nowadays, they are asking 'how fast can you deliver the vision system?'" He gave another example. "Food and beverage manufacturers are using the technology to ensure that labels are placed on packaging correctly. They strive for perfection because putting the wrong label on a product or a label that is slightly misaligned, can have disastrous consequences." Braggins recalled a UK-based biscuit manufacturer that was using a vision system to inspect the dimensions and 'brownness' of the biscuits passing down the production line. It was used in conjunction with the firm's SPC quality system and warned production when the biscuits were starting to reach 'unacceptable' levels. The chefs were then alerted and the recipe changed accordingly. The latest vision systems, he added, are more robust and capable of more precise measurement and inspection. "A manufacturer of mints was using vision technology to guarantee the fat content. The meat that was being cut up to produce the mints needed to have a limit of 30% fat content. The payback on this vision system was very good," he recalled. Pharmaceutical companies are also using vision technology to check that the product codes on drugs are correct, and positioned correctly, and that batches of drugs are identical to the master. The printing industry also employs the technology on its presses to inspect paternal webs and for in-line inspection at high speeds. Even companies who are concerned about cheap competing products are now using vision systems to detect counterfeit items. The major vision system suppliers include Cognex, DVT, Omron, Matsushita, National Instruments (with its image acquisition software and virtual instrumentation tools), German company Werth and two Canadian companies, Matrox and Coreco. Braggins also referred to a Hungarian supplier of vision systems, Falcon Vision, set up in 1996. The company has developed and patented a vision system that is currently being used by several major European car manufacturers, including a major German one. One of these applications involves a vision system designed to inspect cylinder heads at a rate of one every 30 seconds. Braggins explained that this system takes measurements after the cylinder heads come out of the machining cells. "It checks all the holes are there and that the metal around the holes and the casting are OK. It's not in-process inspection, the system inspects after the machining is complete." Braggins explained that the car maker went down this route because it was receiving too many reject cylinder head castings from its foundry supplier. So the foundry called in Falcon Vision to try out its technology on one of its transfer lines. "Now, the car manufacturer has its machining cell with a buffer and the vision inspection unit downstream. Any faulty parts are rejected and a mark is stamped on the components for traceability purposes." He added that Falcon is now also supplying its technology to help auto suppliers inspect high precision parts such as plastic car headlamp bulbs. "The best quality ones go into the cars, the slightly inferior quality components go into retail car and spare parts outlets. Employed correctly, vision systems can cut costs and save scrap and re-work for manufacturing firms. Braggins told Eureka: "A company in the US saved lots of money using vision to 100% inspect PCBs. The manufacturer couldn't work out why certain boards were being rejected. The vision system discovered that most of the rejects were being found after 10am each day. The problem was eventually found to be the factory cleaners, who came in each day at 10am and used silicone polish which had been getting onto the boards." There are basically three ways companies use vision systems. The first, said Braggins, is for recognition purposes. "Is it actually a left-handed widget. You may want to verify a part or recognise it so that your production process can then place it somewhere else." Second, is for guidance or location. A robot for example may need to pick and place chips in an exact location on a PCB. And third, the largest area is inspection. According to Braggins, companies are using vision systems to inspect glass, metals, plastics, aluminium, film stock - to ensure anything that shouldn't be there is removed or the process stopped. The other use of vision is for colour recognition. This type of technology, he added, is making great strides now, compared to the 1980s, when vision systems could only recognise red, green and blue. "It's also less expensive now and although it is still quite difficult to replicate human vision, there are smart cameras available now with high enough resolution and signal ratios to cope with this type of problem." As for the future, Braggins said that the vision system industry is moving towards intelligent or smart cameras. "These are cheaper and most cameras are now easy to set up," he continued. "The number of cameras sold world-wide is on the up too. Users can now afford them, the robustness of the cameras has improved and the equipment can cope with faster, higher throughput production environments. "Electronic shutters on the latest cameras mean that motion can be frozen and you can connect the units to the Internet or a local area network in order to view your production processes remotely. Options such as Ethernet and Firewire are also available now and special LEDs for illumination purposes," he concluded. NOTE****Founded in 1992, the UK Industrial Vision Association is a not-for-profit organisation whose primary objective is promotion of the use of vision technology in UK manufacturing industry. Although some members of the Association have been supplying vision systems for more than 20 years, the technology is still considered 'new' and so the Association exists to provide reassurance and factual information about the capabilities of vision. The organisation's website www.ukiva.org contains a search engine to help manufacturers identify suitable suppliers of vision systems, plus information about members, seminars, newsletters, directories and a free telephone advice helpline.