Packing line upgrade for sorting and defect elimination

Rexam, Sweden: Better bottling thanks to Cognex vision systems

Supplying packaging to the world’s high profile consumer drinks manufacturers is serious business. Rexam is investing in vision to automatically inspect bottles in order to ensure that they are intact, clean and meet safety standards.

Rexam, a global enterprise that manufactures consumer packaging, is a world leader in plastic packaging for the cosmetic, pharmaceutical, food and beverage industries. Rexam’s plastic beverage container operations are located in Germany, Sweden and the Czech Republic. Sweden is home to two plastic manufacturing factories for food and beverages as well as one tin factory and a glass-works.

Great expectations
Rexam’s customers are large soft drink manufacturers in Nordic countries, such as Carlsberg, Spendrups and Coca-Cola. They all have high expectations and demands regarding the quality, logistics and visual appearance of these plastic bottles as well as end-consumer satisfaction. Rexam’s bottle factory in Lidköping, as well as other locations, manufactures 80 percent of all bottles sold in Nordic countries.

At Rexam in Lidköping, beverage containers are manufactured in five shifts round the clock, all year long. Rexam manufactures two main sorts of bottles, which are either refillable or recyclable. Refillable bottles are washed and refilled up to twenty-five times, while recyclable bottles are filled once and then ground up to be reused as raw material for new bottles, fleece clothing or another product using polyester as a raw material.

Vision: a key investment for long term quality control
By the end of the 1990’s the company had begun to invest in vision systems in order to improve the quality and reduce the number of errors in the manufactured beverage containers. Then the company got an order from an important customer to develop a beer-bottle made of polyethylene naphthalene (PEN). These bottles have a more glass-like quality compared to their PET bottles and can withstand higher temperatures during washing.

Improved customer relations
During the manufacturing of the PEN bottles, a problem arose with air-bubbles appearing in a small number of them. The customer was concerned that the bubbles would cause cracks thus risking contamination. Rexam decided to implement vision systems from Cognex in order to develop a process of sorting out defective bottles thus eliminating the problem reducing the failure rate to almost nil. “A strained customer relationship was transformed into a positive customer relationship once the problem was solved”, recalls Urban Larsson, production manager at Rexam Petainer in Lidköping. “That was the gateway into an array of various quality-control projects at Rexam in other areas of our production and that is why the use of vision systems is one of our corner-stones.”

Reliable refilling
Rexam has continued to invest in vision systems in order to ensure the quality demands of refillable bottles as well. During the manufacturer’s own filling operations the bottles are washed carefully. A vision system quality-control check during manufacturing detects any bottles which contain objects or contaminants that cannot be washed out. Cosmetic defects such as air-bubbles can occur during the manufacture of individual bottles. These are detected as the bottles are inflated. Vision systems also check the seal with the bottle-cap to eliminate the risk of leakage. The appearance of the bottles has also become more and more important over the last few years. Bottles with scratches, chips and imperfections such as air-bubbles and other cosmetic defects which in themselves do not affect the function of the bottle are systematically processed through the use of vision.

Environmental friendly
Use of vision systems is a part of Rexam’s efforts to become a resource-efficient company. For improved quality and customer-satisfaction in the face of stiff competition. With the use of vision systems, the quality of bottle manufacturing is assured. The amount of unnecessary waste is eliminated through vision inspection.

In-Sight with Patmax: the packaging industry’s chosen vision solution
“During the past five or six years, our investment in vision systems has really paid off”, says Urban Larsson. “We have gone from doing manual random-sample testing and inspections of a production of several hundred million bottles per year, to a systematic inspection of everything that is manufactured. Through automated inspections, we have a wide cover which together with other quality-control measures minimizes the incidence of error”.

The manufacture of plastic bottles, which saw the launch of quality-control, is on-going, while new products are continuously being developed.

“Our choice of vision provider is based upon Cognex knowledge and experience with vision technology and the needs of the packaging industry,” says Urban Larsson. “Cognex has developed and provided industrial vision technology for 25 years of cost-efficiency with a minimal or non-existent rate of failure in production. Rexam uses the In-Sight type of vision systems which are tailored for automated inspection and verification of quickly moving objects. PatMax ® software is used for property and object localization, and works well when inspecting consumer-product packages.”

“The visual and functional requirements are becoming more and more important in the packaging industry.” says Urban Larsson. “Our customers attach more and more importance to the package’s design. By means of a structured working method, preventative maintenance procedures and various improvement projects, we can quickly adjust our production to meet the various needs of our customers. Using a colorful collection of constant improvements, we have built up a reputation for good quality”, concludes Urban Larsson.

Unilever gets a boost from Robotics

Quick-change versatility and a boost in throughput are two of the benefits gained since a four-robot packaging cell was installed at this Unilever meat plant in Germany.

Seasonal promotions and other marketing initiatives designed to last briefly and change frequently are becoming increasingly important in the fast-moving world of consumer packaged goods. Consumers, too, want ever more variety in the size, shape, and flavor of the products they buy. That means today’s packaging lines must be more versatile than ever, and more often than not they’re gaining that versatility through robotics.

A perfect example can be found at the Unilever plant in Ansbach, Germany, where the popular sausage snack known as Bifi is produced. The recent installation of four delta-style flex-picker robots from ABB (www.abb.com) lets Unilever go from handling one size sausage to another in about three minutes. It also lets Unilever redeploy as many as six operators who used to be required for hand packing of the sausages into thermoformed rollstock. And while the previously manual operation could only feed the downstream thermoform/seal system at 8 cycles/min, that machine now runs routinely at 15 cycles/min because the upstream robotic packaging cell is comfortable at that pace.

In operation since March, 2006, this is the second robotic packaging cell installed at the Ansbach plant. The first uses five delta-style robots to handle about 360 sausages/min. By comparison, the newest cell uses four robots instead of five and handles nearly 600 sausages/min. Permitting this surge in throughput and efficiency are improvements in both hardware and software. On the hardware side, the end effector on each robot is a triple-gripper. Each time it carries sausages to a thermoformed package, it does so three at a time.

Also notable is that only minor mechanical adjustments are required when Unilever changes to any of six sausage diameters. New parameters are chosen at a touchscreen and the pneumatically actuated mechanical grippers pretty much ready themselves for a new sausage diameter.

Nimble and sure-handed, the end-effectors were designed and built by Schunk (www.schunk.com) in collaboration with robomotion (www.robomotion.de), a specialist in robotics. Robomotion also had integration responsibilities on the robotic installation. One of robomotion’s key accomplishments was keeping the footprint of the robotic cell to a mere 2.5 x 3.5 m (8.20’ x 11.48’). Software played a key role in making this possible because it minimizes the distance that the robotic end effectors must travel. More on this later.

From cutting to packaging

Individual units of the sausage product are cut from long strings in a room adjacent to the packaging room. Their ultimate goal is to make their way into the thermoformed cavities produced in a multilayer forming web by an R530 system from Multivac (www.multivac.com).
This system forms, evacuates, and backflushes the packs before heat sealing lidding material into place.

A series of conveyors brings the sausages to a vibratory hopper that meters them onto two flat conveyors leading to the robotic cell. Running beneath and perpendicular to these conveyors is the multilayer forming web that has just emerged from the forming station of the Multivac R530 system. The four robots continually pick incoming sausages from the conveyor belts and place them into the rows of thermoformed cavities.

A Siemens (www.siemens.com) PC—plus ABB’s Pickmaster software—is the “brains” behind the robotic system. The PC learns the precise location of sausages on their infeed conveyor from a Cognex (www.cognex.com) vision system mounted at the infeed of the robotic cell. The PC sends to an ABB robotic controller the precise coordinates pinpointing sausage location. The ABB controller then determines the best strategy for one of the four robots to pick which sausages and when; the controller also determines into which thermoformed cavity sausages should be placed.

The number of sausages conveyed into the robotic cell exceeds the capacity of the four robotic heads. That way, the robots are never “starved” of incoming product. Besides, it’s inevitable that some sausages will land on the conveyor so close to each other that the robotic end effectors would have difficulty picking just one or the other. The Cognex vision system sees this condition and relays it to the Siemens PC, which in turn communicates with the ABB controller so that ultimately the robots will be steered to other, more readily picked, sausages. Sausages that don’t get picked tumble from the conveyor and are automatically recirculated back through the robotic cell again.

The exchange of information from vision system to PC to robotic controller takes place via an industrial Ethernet connection. ABB’s PickMaster software is a key tool used to tightly integrate the motion of the robots, the infeed conveyors, and the vision system. The powerful combination of robotics and vision brings great flexibility and an ability to make format changes quickly. According to Henrik Knobel, product manager at ABB, Cognex vision was chosen on the strength of its technology and because it offered efficient PC-software interfaces for integrating the vision functions in ABB’s robot technology. “Industrial vision technology gives a broad range of ABB robots the eyes to see where parts are located and to pick them accurately,” says Knobel.

The image processing system brings an added quality-control benefit. “Each individual product is measured and compared to a predetermined set of parameters,” says Torsten Ruetze, project engineer at Unilever. This provides a statistical record of how many pieces are too thick or long or thin or optically defective.

Software’s role

Additional software written by robomotion and running on the ABB controller also plays a key role. It executes what robovision’s Andreas Wolf calls “path planning.” He explains it this way.

“The Siemens PC is the brain that decides where the robots should go to pick the sausages,” says Wolf. “But the ABB controller, upon receiving that information from the PC, then decides the best paths for all four robots to take. It’s a bit trickier than usual in this particular case because, in order to keep the overall system footprint to a minimum, we designed it so that the robots’ paths sometimes overlap. Without the proper software programming, the robots would crash into each other.”

That they don’t crash into each other is one of the more remarkable things about watching the system work. Be sure to see the video footage.

Date-coding is handled by a bank of eight Videojet (www.videojet.com) ink-jet coders. Once past these coders, a cutting station separates individual packs from the web of material. Secondary packaging, for the time being, is done manually.

Once the thermoformed cavities are filled with sausages, they proceed to the station of the Multivac system that evacuates ambient air and backflushes each cavity with nitrogen before heat sealing the lidding material in place. Just ahead of this station is a second Cognex vision system that checks to see if any package is without product. If it finds one, a signal is sent to the downstream cutting station to prevent the cutting tools from cutting that group of packages from the web. An operator then places the uncut group aside. In this way, the empty cavity is prevented from making its way out of the plant.

Ruetze says the key contribution made by the robots is that they now allow the line to operate at optimal speed. He’s also pleased that it took only 10 days to get the system installed and put into commercial operation.

“This was an important project for us,” he adds.

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21st Century Vision

Cognex founder Dr. Bob Shillman with an early Cognex test system.

Today’s Cognex DataMan 100 fixed mount ID reader packs
much more functionality into a much smaller package.

Today’s vision systems have come a long way since the first DataMan system was developed in the early 1980s.  The functionality and user-focused design now available to Cognex customers is the result of more than 25 years of hands-on experience developing new vision technology and solving the industry’s most challenging vision applications.

Today, Cognex retains its focus as a company of “vision experts.”  The company continues to investigate new ways to improve performance of industrial machine vision, while also exploring new markets where vision can provide a competitive advantage, such as transportation (lane departure warning systems) and building security (monitoring secure portals and doorways).

Each of Cognex’s three founders continues to play an important role within the company: Bob Shillman is Cognex’s Chairman and CEO; Marilyn Matz is Senior Vice President of the Vision Software Business Group, and Bill Silver is Senior Vice President and Senior Fellow, pursuing research into new product areas.

All three founders – along with a team of some 800 Cognoids – continue to work hard to maintain the company’s worldwide position as industry leader in machine vision.

Cognex Becomes a Market Leader in Vision Systems!

In 2004, Cognex was invited to open trading at Nasdaq in
celebration of its 15th year as a publicly-traded company.

Cognex’s OEM-focused strategy paid off. In early 1987, the company became profitable for the first time in its history. Cognex went public on the NASDAQ exchange in 1989, at $1.38 per share. Within one year, the stock price had tripled.

Cognex set about growing its business in this period by expanding internationally.

In 1989, Cognex opened its first international office in Munich, Germany.  In 1990, Cognex established a Tokyo-based subsidiary, Cognex KK, to serve the company’s rapidly growing business with large semiconductor and electronics capital equipment makers in Japan.  Today, Cognex has more than 20 offices throughout North America, Europe, and Asia to serve its worldwide customer base, and hundreds of distributors around the world that carry Cognex Vision Systems.

In 1995 the company also made the first of many acquisitions when it purchased Acumen, a U.S. based developer of wafer identification equipment for the semiconductor industry. Acquisitions have played an important role in the company’s growth, and enabled Cognex to enter new markets for Vision Systems such as surface inspection, and vehicle vision.

New In-Sight Micro boosts automotive suppliers’ production

New In-Sight Micro boosts automotive suppliers’ production

…. “Using the new Cognex In-Sight Micro vision system with its compact size and high performance, has ensured our customer can build their parts safe in the knowledge that there will be no product defects due to appliqué clipping.”  Visteon, based in Portugal, is using the new In-Sight Micro from Cognex as recommended and installed by Cognex specialist partner integrator Alphr Technology, based in the UK, to optimize the production of automotive control panels.

Wanted – pinpoint precision Visteon is a leading supplier to the top automotive manufacturers in the world. With their business covering a number of key areas including Climate Control, Electronics, Interiors and Lighting, there is no room for error in product delivery. Amongst an impressive product range within their electronics business, Visteon supplies instrument panels for many executive car models across Europe. One vital element of the panel involves the appliqué, a plastic sheet incorporating the speedo and tacho markings. Each appliqué must be clipped into position with pinpoint precision; otherwise the vibration from driving the car could make the appliqué move, resulting in the incorrect speed and revs being shown.

High volume production requires a powerful vision solution
To ensure accurate assembly verification, it was time to bring in a powerful vision system which could not only could cope with Visteon’s high-volume panel production but also fit within the confines of the allocated space.

The partner of choice
Ensuring the most capable and cost-effective vision system would be used; Visteon called upon its trusted vision technology supplier Alphr Technology Ltd. Based in the UK, Alphr Technology has been working with Visteon for a number of years and had previously installed similar lines at their plant in Portugal, as well as other factories across Hungary, Mexico and India. Offering a complete solution, Alphr would design, build, programme and retro-fit the system on-site at their facility in Portugal.

Precision inspection with the In-Sight Micro
Having assessed the project requirements, Alphr selected Cognex’s brand new high-performance In-Sight® Micro to achieve the required inspection rates. Launched earlier this year and measuring just 30mm x 30mm x 60mm, the In-Sight Micro is a unique and powerful vision system, specifically designed to offer outstanding performance as well as fit within confined areas, a common issue in many production facilities.

This new system would also complement two existing Cognex In-Sight 1000 cameras, successfully inspecting pointer alignment for the speedo, tacho, fuel and temperature gauges on each instrument panel.

The production line
To cope with customer demand, two identical production lines were required, running simultaneously in three x 8 hour shifts, 5 days a week, producing 2000 parts per day. Two In-Sight Micro cameras are fitted per production line and are mounted onto a FlexLink frame with LED spot lights mounted alongside the cameras.

Both production lines assemble the PCB with the necessary plastics and LCDs and fully test the parts. Using PatMax®, Cognex’s industry-leading geometric pattern matching technology, the cameras search for two plastic pips positioned at 3 o’clock and 9 o’clock on each appliqué’s white circle. If these pips are obscured, the appliqué is sitting on top of the clip rather than behind it and is therefore not affixed correctly. The power of the PatMax software ensures each feature is located despite any process variation.

Each part is manually loaded onto the rig by an operator and then removed once the inspection is complete. Results are viewed on a PC monitor using a test program written in Visual Basic 6. Failure tickets are printed for the operators and all results are sent to a factory CIM system to monitor performance. Any defective parts are manually removed from the rig, once the operator has pressed the ‘reject acknowledgement’ key.

Success breeds success!
Speed of production has been unaffected despite the new inspection requirement; as the In-Sight Micros inspect each appliqué in a fraction of a second, ensuring production and optimum throughput remains constant. Declan McCabe, Applications Engineer at Alphr Technology was responsible for the electrical design, software development and installation. “Visteon was so impressed with the success of this project; they have requested a quotation for an identical system on another production line.”

Cognex’s Company History

A New Company, and a New Industry

Cognex founders Robert J. Shillman (seated), Marilyn Matz
and Bill Silver in a photo taken for a 2004 Fortune
magazine article entitled, “Heroes of Manufacturing.”

Cognex Corporation was founded in 1981 by Dr. Robert J. Shillman, a lecturer in human visual perception at the Massachusetts Institute of Technology. Dr. Shillman decided to leave academia to start Cognex, investing his life savings of $100,000 into the company. He invited two MIT graduate students – Marilyn Matz and Bill Silver – to embark on this business venture with him, offering free bicycles to convince them to leave MIT for a summer. What began as a summer job for Marilyn and Bill turned out to be the start of a career, as they stayed on to help co-found the company. These three individuals gave Cognex its start – and its name, which was derived from the phrase “Cognition Experts”.

Welcome,

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The Vision Guy!