New In-Sight Micro boosts automotive suppliers’ production

New In-Sight Micro boosts automotive suppliers’ production

…. “Using the new Cognex In-Sight Micro vision sensor 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 vision sensors 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.”

Assembly line upgrade boosts profitability

Cognex In-Sight® sensors checking the quality of laser welds at Renault - Sandouville

Cognex Corporation (NASDAQ: CGNX), the world’s leading supplier of vision systems, sensors and bar code readers presents an application of industrial vision in the automobile industry. Operating at Renault’s factory at Sandouville, this application involves checking laser weld imperfections that sometimes cause an assembled vehicle to be sent to the scrapyard. Here is an example of what can be obtained by using industrial vision to do quality checks before adding value to parts on a production line.

The Renault LHA factory is located in the Haute Normandie region, in the town of Sandouville, and more precisely in the port and industrial estate of Le Havre (in the Seine-Maritime Department). This sizeable bodywork-assembly plant is specialised in the manufacture of top-of-the-range vehicles: the Laguna line of automobiles, the Vel Satis and Espace IV. As the main production plant for these vehicles, it occupies a total surface area of 152 hectares, 60 hectares of which is built on, and employs nearly 6000 people.

The site includes four manufacturing departments: pressing, sheet metal, paintwork and assembly, along with eight departments and sections carrying out support functions. The production capacity is 1900 vehicles per day. The Sandouville factory was the Renault Group’s first bodywork-assembly plant to receive ISO 14001* certification in December 1998.

The vision application presented here was set up in the pressing workshop. This workshop produces sheet metal parts that make up the body shell of the vehicles. It mainly comprises cutting lines, assembly and sheet welding points, as well as sheet presses which make up the various bodywork components. The pressing workshop supplies the sheet metal workshop which carries out the assembly of the various parts of the body shell. This then passes on to the paint shop before final assembly.

The vision system installed is designed for checking the right and left sides of the body shell of the Laguna cars. The same installation is therefore able to check four different parts.

Each side of the body shell is made up of two parts which have been assembled by laser welding. It is around the weld that defects can appear and need to be detected. While the various pressing operations – which give the part its shape – are being carried out, clear or partial breaks can be produced. As the parts are stored manually at the end of the line, those parts showing such faults are easy to spot and remove.

It is not so easy to spot when the faults are small holes, some of which can measure less than 3/10th of a millimetre, which form along the bead of the weld. If the presence of these holes is not detected at the end of the line, and if the part is not removed, breaks can be produced during shaping, causing numerous problems which can have serious effects on the productivity of the assembly line. Sometimes minute holes are enough to give the bodywork an unsightly appearance after the paintwork has been done.

If these defects are not detected before the vehicle is assembled, the consequences can be financially very expensive as it is very difficult to repair…and sometimes there is no other choice but to send the chassis to the scrapyard.

Checking the welding was previously done by several operators who had to struggle to handle parts of a considerable size and weight: the sides of the body shell measure around 3.4 metres in length, 1.6 metres wide and weigh nearly 30kg. To carry out the operation, they used to place a light source on one side of the part and check from the other side that the light did not pass through, showing breaks or holes in the part. This form of control, even when it was done in the optimum way, cannot highlight holes of a very small diameter.

Numerous defective parts passed through these checks, so a solution had to be found which was capable of putting a stop to this situation while carrying out a continual and reliable check of the lower body shells.

At Renault Sandouville, Patrice Dumont is the Automated Systems Manager. He is part of the DIVD (the decentralised vehicle engineering department) Pressing Section, attached to the Renault Technocentre at Saint Quentin in Yvelines.

Some time before, Patrice Dumont had the opportunity to attend a seminar given by the machine vision company: Cognex. He realised that vision systems, which are used widely in industry were a better alternative to other control procedures, and that they could be the solution to the problem. They reduce the difficulty of certain tasks that are normally carried out by operators. Not being affected by tiredness like the human eye, they continually work guaranteeing quality and improving productivity.

Patrice Dumont decided to evaluate a solution based on industrial vision systems and an integrator of the Renault Sandouville factory was called in. It was necessary to be sure that this type of check could be suitably carried out with a vision system and a prototype could be quickly produced for a first test. Several vision systems manufacturers were called upon. Cognex was the most reactive, and it was the In-Sight® vision sensors range which were chosen for the operation.

In July 2002 the prototype was tested. The trials proved very conclusive: the tests carried out were 100% correct. The Cognex In-Sight vision sensors detected all the faults. Terms and Conditions were drawn up and a first test bench was ordered. It was specified that the system should be capable of detecting holes with a diameter of 3/10th of a millimetre. In reality, the system would demonstrate that it could do better than that.

The first test bench was put into service around mid-2003. A second test bench, with smaller dimensions, was ordered later for checking the side frames of several vehicles (Laguna, Vel Satis and Espace) on another line. Each test bench has 4 Cognex In-Sight vision sensors.

The body shell side test bench

The first test bench is a metal frame around 5 metres long and 2 metres wide, weighing 5 tonnes, with a 5cm thick platform holding the structures on which the parts to be checked are placed, along with a backlighting system with LED indicators. The test bench was put in place by a bridge at the end of the pressing line each time the manufacture of the Laguna lower body shell is started up.

Four Cognex In-Sight 1000 cameras, each placed in protective casing, are positioned at the top, over the platform, on the cross support beam. A control screen is fixed on one side of the test bench, in a box where the control system is also installed. A marking system for defective parts is fitted at the other end.

The parts to be checked – body shell sides – measure around 3.4 metres long, 1.6 metres wide, and weigh nearly 30kg. They are put onto the supports provided for this purpose on the test bench by a robot. There are two areas to be checked. The target areas measure approximately 10 centimetres in length, by 5 centimetres wide, with a covering. Two of the cameras are inclined at 45 °, the part forming a U-shape over the welded area.

The cameras are able to detect very low light levels coming from the backlighting system and passing through any holes, some of which are only a tenth of a millimetre in diameter.

If the part is declared sound, this is displayed on the control screen. If the part is defective, it is also displayed on the screen, a red light comes on at the end of the line for each fault, and finally, the part is marked by a jet of ink which stops it from being used.

The speed of the control carried out on the line was a determining factor of the project: all the operations – positioning the part, capture and analysis of the image, detection and marking could not reduce the production rate in any case. At this stage, the Cognex systems proved their worth: the production rate specified in the Terms and Conditions was 900 parts per hour; the current production rate is 420 parts per hour for the body shell sides and 850 parts per hour for the side frames.

The system is connected to a PC fitted with a hard drive for saving the photos of the defective parts detected over one year. This procedure allows the problems encountered to be analysed at a later date; it contributes in ensuring the traceability of parts and for monitoring the various shifts (days, hours, cameras 1 and 2…).

Simplicity of operation

The aim of this project was to find a method and a system for automating the checking of welds. The principle of the checks relies on the backlighting of the area to be inspected. Resorting to a camera for seeing if rays of light cross through the welded area was logical. However, in order to “industrialise” the solution, there were still several points to be checked: firstly that the tools for processing the images acquired were efficient enough – i.e. precise and reliable – to recognise all the types of faults, including those difficult to detect with the naked eye, and secondly to carry out a 100% check without reducing the speed of production.

“We had to teach the system what faults were to be identified”, stated Patrice Dumont. “That was done progressively, at the same time that we were familiarising ourselves with the system. Once the system had memorised the type of fault, the recognition rate was 99.99%”, he added.

The main concern which had to be overcome concerned the ambient lighting. Because of the existing lighting in the workshop, the layout of the area (glazed surfaces) and the orientation, reflections appearing on the parts occasionally disrupted the operation and showed faults…which were nonexistent. Placing curtains at the end of the line resolved this problem.

The welding checks are now carried out reliably on the whole production (body shell sides and side frames). With the fault recognition rate obtained, the defective parts are very quickly identified and removed at the end of the pressing line. “An end to the time when entire body shells had to be sent to the scrapyard”, stated Patrice Dumont. “The savings made at this stage alone fully justify the investment. The fact that the vision control point is shared by four parts also contributes to the increase in its profitability.”

This method of checking welds with industrial vision tools is of interest to other sites and is likely to be brought into general use. A patent has been registered covering the principle used.

Assembly verification with vision guided robotics

Automobile assembly time reduced by 20% with In-Sight

When they decided to implement a vision guided robot solution based on In-Sight™ vision technology from Cognex, S.A.P. reduced assembly time for an important automotive client by 20%. Cognex distributor Edge Vision recommended In-Sight as a robust solution for their client. Since 1980, S.A.P. (Sistemas Automatizacion Procesos, S.L.) in Barcelona., has been providing solutions and components for the automatisation of industrial processes. With customized facilities the company is in a position to provide “turn-key” solutions such as robotic applications and the resolution of complex problems guaranteeing maximum reliability.

The challenge : 1 automotive part - 70 different points for inspection

SAP found themselves faced with a quality control challenge. One of their automotive customers needed a special machine for the assembly and inspection of certain part for a van. The part concerned resembles an iron tube and is a key element of the internal structure of the van containing 70 different points of inspection such a welded nuts, screws and holes. The industrial environment concerned would be dusty and oily with variable lighting and many of the parts to be inspected were also liable to be oily and dirty which would make them difficult to find and reliably inspect. S.A.P. turned to Edge Vision, a Cognex distributor, seeking a robust and reliable solution. Edge Vision decided on the In-Sight range of vision systems, fully robust and capable of handling an instable and variable operating environment

Take a robot and give it “eyes”

Edge Vision, a Cognex distributor decided to install a vision guided robotic solution. They placed an In-Sight 5100 at the end of the arm of a robot. The position of each point to be inspected is communicated to the robot. The robot « learns » the route to follow and inspects all points using the In-Sight 5100 as « eyes » . Points to be checked include welded nuts, holes, and screws. Cognex vision tool, Patmax™ proved essential. This powerful algorithm, unique to the In-Sight product range played a vital role in part localisation under such conditions. Information is communicated to a user-friendly PC interface. Progress can be easily monitored and results recorded by the operators.

Result

The usual production and assembly time for this particular van is reduced by 20%. The process has been made a lot safer, more reliable, faster and cost-effective . Previously this would have had to been done mechanically. Plus, In-Sight vision sensors were the only products capable of handling a hostile industrial environment thanks to their robustness. As a result, potential faults down the line are reduced to a minimum preventing future costly product recalls.

David Torres from Edge Vision, had this to say – “By implementing this robotic solution based on In-Sight vision systems from Cognex, our client has been able to reduce production cycle time by 20%, thus saving money and boosting productivity in the same manner. In-Sight will be included as a standard option on their machines from now on.”

Multi-point quality inspection for gearboxes

Top performance Saab Automobile gearboxes profit from automatic inspection using Cognex machine vision sensors

Saab Automobile PowerTrain AB is a subsidiary of Fiat-GM PowerTrain and manufactures gearboxes for worldwide export to GM plants. For over 50 years they have been producing gearboxes for Saab cars and today do so at the rate of 700 units a day. The factory also makes gearboxes for the Opel Vectra, Opel Zafira and for Saturn in the US.

At one time Saab Automobile PowerTrain manually made inspections of the gearboxes before their delivery to customer plants. The manual inspection demanded quality control of 60-70 inspection-points on the gearboxes which was time consuming and not fully reliable. The other disadvantage was that many varieties of gearboxes were being manufactured with very subtle differences between them, which is a big challenge when using manual inspection. Customer demands for shorter and shorter lead times created the need for a more efficient and less time-intensive inspection. It became clear that automatic inspection was necessary in order to guarantee product quality.

40 seconds for complete inspection

A complete multipoint inspection of the 60-70 spots on the gearbox is made in 40 seconds with a vision-equipped robot. This means that several inspections are made per second. For the demanding conditions of the inspection application, Saab selected a solution based on collaboration between Cognex and their Partner System Integrator Svedvision Systems AB. This experienced and highly skilled robotics integrator developed a robot guidance and inspection cell that is perfectly adapted to the specifications of the project and is used for the gearbox application. The choice of suppliers for this solution was easy because it was based on the fact that Cognex and Svedvision have real in-depth knowledge of the automotive industry worldwide. Cognex has been pioneering the vision industry for 24 years and Svedvision Systems AB, founded in1988, have a long history of integrating machine vision.

The PatMax® software featured in VisionPro® (the PC-based development environment from Cognex) was integrated into the platform that handles both the robot and vision using a 3D-measurement unit developed by Svedvision using search, edge and ID-tools.

The application consists of:

• Inspecting all mounting parts that are visible from the outside
• Inspecting hole and screw threading
• Checking mounted screws and that they are fastened on the gearbox
• ID-reading on parts
• Gearbox label verification
• Gearbox ID Verification

No customer complaints in 17 months

“Saab needed to eliminate manual inspection, which is an unreliable solution compared to high-performance automated inspection“ says Ulf Svensson, Group Leader of Manufacturing Engineering Saab Automobile PowerTrain. “Automating the inspection process allows Saab to set a standard and demonstrate that money is being invested on improvements that are in keeping with our customer’s needs. In order to stay competitive we have to ensure increasingly shorter lead times and high-quality performance. It is important that we listen to our customers and be reactive to their concerns.”

Ulf Svensson continues: “Through the application a reliable and robust final inspection system of the gearboxes has been implemented. The inspection system adjusts itself to all types of gearboxes that are produced at this plant. The inspection system has been a good reference in the total quality management program that is implemented by Saab. Thanks to the fully integrated solution proposed by Svedvision Systems and Cognex, all gearboxes delivered are inspected and feature zero defects.”

The result of automating inspection at Saab Automobile PowerTrain AB in Gothenburg, Sweden has been no customer complaints in 17 months. This is virtually unheard of in the automotive industry.

There are other examples of vision use at Saab Automobile Power Train such as a vision system in the assembly department to check that critical parts are mounted. At Saab Automobile PowerTrain AB the automation of production is a reality and it is an important competitive element in this day and age. It is clear that the use of vision to check critical issues will be an efficient alternative to ordinary manual checks in the future.

Retaining ring measurement

Vision sensor improves ring measurement process

Rotor Clip is the world’s leading manufacturer of retaining rings, producing billions of rings annually at its 238,000 square foot production facility in Somerset, New Jersey.  From steering wheel assemblies to household appliances, Rotor Clip retaining rings help secure components onto shafts and inside bores.  Rings are produced in a wide range of sizes, from 1/25” (1mm) to 35” (889mm).

While the company has long relied on micrometers for measuring ring dimensions, operators were having trouble measuring rings that were less than half an inch in size. “When you have a ring that is about 1/8” in diameter, it’s very difficult for an operator to handle and place them in a micrometer,” explains Ed Engracia, a design engineer for Rotor Clip.  “Also, when the operator is using a vernier caliper, there’s a lot of room for error.  The operator could be pressing too hard in one instance, too lightly in another.”

Measurement speed, according to Engracia, was another problem.  Manually measuring six small-sized rings, he says, can take an operator up to 20 minutes.

To speed up the measurement process and improve accuracy, the company recently added an In-Sight® 1000 machine vision sensor from Cognex Corporation (Natick, MA) to its manufacturing line.  The In-Sight 1000 is a high-performance, general purpose vision sensor which incorporates a full library of vision software tools, built-in discrete I/O, a vision spreadsheet interface for application set up, and built-in Ethernet communications in a compact, self-contained unit.

According to Engracia, one of the primary reasons the In-Sight sensor was selected was due to its ability to store individual measurement programs or “jobs” that corresponded to each ring type via the vision spreadsheet interface.  “We had to make things as easy as possible for our operators since they had no previous experience with machine vision,“ he says.  “In-Sight was attractive because it had built in functions, which made it easy to customize a job for each part we wanted to measure with the vision system.  So all the operator needs to do is call up the job to start.”

To set up the programs, Engracia selected vision tools and parameters from the spreadsheet’s drop-down menus.  The vision spreadsheet then automatically generated tool results into worksheet cells, which were linked together to set up the measurement routine for each part.

Engracia designed the inspection station so the micrometer equipment and vision sensor are housed in the same hooded enclosure.  Operators retrieve retaining rings from collection bins, and after a few thickness measurements are taken by micrometers, a single ring is placed on a four-inch backlight component under the vision sensor.  Backlighting, according to Engracia, provides the optimal image contrast to get good dimensional data.

Once the operator brings up the measurement program that corresponds to the ring’s size, In-Sight captures an image of the ring from seven inches above and transfers it to its built-in vision processor.  There, a number of vision software tools are used to analyze the image.

“We measure a lot of different features,” says Engracia.  “On some rings, we only look at outside diameter and lug size, whereas for another ring type we might need to measure the inside diameter, min sections, max sections, and lug hole diameters.  Needless to say, it was important to have a range of vision tools to choose from so we could handle the different rings.”

More specifically, Engracia uses the In-Sight PatFind™ pattern location tool, which verifies the presence/absence of the part and applies a virtual fixture to “fixture” the part for the different measuring functions, the Find Circle Tool, which measures diameters, and the Find Segment Tool, which measures segment sizes.

As the measurements occur, operators can get a real-time view on a color LCD screen that is built into the inspection station enclosure.  “We were able to create a custom user interface with In-Sight that displays the various dimensions of the ring taken with the camera, and pass/fail lights in green and red which indicate if the part is good or bad,” explains Engracia.  “If any of the dimensions fall outside of tolerance, it’s usually an indication of the die being out of adjustment, in which case they have to stop the production equipment and make adjustments to the dies.”

One interesting feature of the new inspection station is that the micrometer equipment and vision sensor are linked via Ethernet, thus allowing thickness measurement data from the micrometers to be uploaded into the In-Sight program.  The combined micrometer and vision data is then sent over into a Quality Assurance database, giving QA engineers instant access to statistical data on each part in the event there is a customer complaint.  “If we need to backtrack on any problems that arise, it’s a lot easier for us to get the data we need from a database versus looking through paperwork,” Engracia explains.  “In-Sight puts everything into computer form, so the QA guys can just cut and paste the data into their statistical software.”

In-Sight’s built-in Ethernet communications also makes life easier for Engracia when he needs to monitor or control vision activity remotely.  “If someone’s having a problem on the floor, I can check it right from my desk and sometimes troubleshoot right from there.  I can also load new In-Sight programs remotely as they are needed.”

Since the In-Sight sensor was implemented since January 2003, it has improved Rotor Clip’s measurement accuracy, and the company has been able to reduce its overall measurement time by 75 %.  “Since our guys no longer have to handle such small parts, they can get the measurements done in far less time.  What used to take 20 minutes for six rings is now down to five,” says Engracia.

The company is currently in the process of adding another In-Sight sensor, the In-Sight 4001 — which provides high-resolution optics (1024 x 768 pixels) for capturing high-accuracy images of larger parts.  This sensor will be designated for inspecting retaining rings up to four inches in diameter.

Automated inspection system for quality control

COGNEX VISION SYSTEMS GUARANTEE THE QUALITY OF PLASTIC COMPONENTS FOR THE AUTOMOBILE INDUSTRY

Thanks to the In-Sight® 5100 vision sensor, OCSA can guarantee that the plastic components they produce for the automobile industry are totally free from faults.

OCSA S.p.A., a company specialising in moulding plastics, produces plastic parts for major organisations operating both in Italy and Europe-wide. One of the cornerstones of the strategy of this company, located in Creazzo (VI), has been the adoption of the most advanced, innovative technologies for automating production and quality control.

100% Control

OCSA received a major order to produce plastic components for the automobile industry. One of the requirements imposed was total exclusion of faults on the components produced. To meet this requirement, the company’s management decided to use a vision system, and their choice was the Cognex® In-Sight line vision systems. The reasons for this are explained by Marco Milan, the owner of OCSA: “First of all, we were aware of the fact that only a vision system would be able to meet our client’s requirement in full, and, in second place, we had already installed a vision solution based on Cognex In-Sight systems to carry out inspection tasks, and this had produced excellent results.”
In this case, the task of the vision system is to check with extreme accuracy the quality of each item produced, and to reject any found to be faulty. In greater detail, this system is able to intercept parts that show imperfections of any kind, such as geometrical defects, excess or lack of plastic material, presence of oil or other impurities on the plastic body.
The vision system was installed on equipment expressly dedicated to monitoring the operation described above. The total equipment consisted, in addition to the vision system, of a vibrating unit that sends through the parts to undergo inspection, a conveyor belt, which moves the parts under the remote camera, and a pneumatic discharge system, which removes faulty parts. The whole system, controlled by a PLC, has been designed and produced by TEC Srl of Lissone (MI), a systems integrator working with Cognex.
As to the vision sensor itself, Ocsa’s technical staff opted for the model In-Sight 5100: this device has been selected for its particular efficiency in terms of processing power, and its sturdy, reliable structure, which means that it can be used in particularly severe conditions.

The importance of the software

Another factor which made a decisive contribution to the decision to use the Cognex solution is the excellent software support: like all the other members of the In-Sight family, the 5100 model is supplied with the full Cognex vision tools library, making available advanced functionalities for the processing and analysis of images.
In the case of OCSA, a tool which is particularly useful has turned out to be PatFind®, a function enabling the In-Sight systems to locate the objects being inspected reliably and repeatably, even in the presence of changes of lighting, angle and scale. Each individual part is recognised and picked up by PatFind. Two geometric options provided by this tool – angle and reference position – make it possible to carry out a detailed in-depth analysis of the geometric characteristics of the object using the edge and blob finding tools.
The results obtained using this vision system have surpassed expectations; all faulty components have been eliminated, while the approved components rejection rate has fallen below 0.5%. Thanks to the high speed of inspection, at 120 parts/minute, there is no negative impact on line productivity.

Seat component vision inspection for assembly

An intelligent inspection solution for smarter seating

As a leading global component supplier to the automotive industry, the Keiper GmbH & Co Group develops and manufactures metal seat components and structures for automotive industry suppliers and manufacturers. Quality control using vision technology on the production line has brought flexible production lines, investment return in under a year and increased efficiency.

Make production more flexible and more reliable

The company’s range of products meets demand in the automotive sector for intelligent adjuster systems and innovative seat structures – both for front and rear. The team at their plant in Germany were looking for new ways to make the presence and variant inspection of components on the production line more flexible and reliable. In the past it used a complex mechanical control system, equipped with a number of touch controls which proved less then dependable.

Challenging : a production obstacle course

Before embarking on a vision solution, the different challenges that would present themselves had to be considered. Various elements in the production process could potentially prove problematic to a vision system:

- some 20 different types of component had to be identified with 100% reliability on each production line
- the individual components needed to be inspected for defects and correct positioning
- components were likely to vary in colour and aspect despite being identical in shape and dimension
- parts may have entirely different colours depending on the supplier
- oily films still present on the surface
- some parts are pitch-black while others have a metallic sheen

In-Sight brings high resolution and accurate object location

Keiper awarded the project to Octum, a Cognex Partner System Integrator (PSI) having considered their vision proposition based on the latest In-Sight® vision sensors. Cognex technology proved capable of providing a vision solution robust enough to handle the challenge. Thanks to the high resolution of the In-Sight 5403 vision sensor, high precision can be assured even for large components when measuring parts offering greater production flexibility. The In-Sight 5400 vision sensor family also benefits from a full range of software tools such as PatMax®. PatMax functions using the geometrical structures of objects (similar to CAD). The most important characteristics of an object such as edges, dimensions, shapes, angles, arcs and shades are isolated, identified and compared to the real-time image. Analysis of the data permits the operator to accurately define the objects position.

Flexible workflow

Reliable feature detection and incorporation of the In-Sight vision sensors in production offer other benefits. For example with the individual component variants there are minor differences as to whether the right or left-hand fitting side of the seat is concerned. Sometimes the right parts are inserted on the wrong side of a seat. Precise feature detection by the vision tools identifies such problems and notifies the operators. The error is corrected and production flow is not interrupted.

Fast - installation in 6 weeks

A complete turnkey system solution was implemented in only 6 weeks. The first control station was installed in June 2006 and has been operating reliably in three shifts including at the weekend since then. Given the satisfactory results, another control cell was established at the Kaiserslautern plant in February 2007. During this time the customer-specific user interface Octum designed for Keiper has proved to be ideal, making programming child’s play for machine operators and maintenance staff.

Real time return on investment

The targets set for the paying back of these production investments are less than a year at Keiper. Markus Röder, one of the people at Keiper responsible for opting for the vision system commented: “Employing a reliable international vision supplier like Cognex offers benefits which have a long-term impact on the entire group and its international production network.”

Robot guided valve inspection

Robot-guided inspection system ensures correct engine assembly at Ford

International Truck and Engine Corporation has recently implemented an innovative robot-guided inspection system at its manufacturing plant in Indianapolis, Indiana to verify the proper placement of valve bridges during assembly.

The diesel engines, which are produced for large Ford pickup trucks, feature 16- valve bridges, which sit on top of the engine’s valve stem.  During head assembly, the valve bridges are placed on top of the valve spring and a rocker arm is placed on top of the bridges.  This whole assembly is then placed onto the engine.  Prior to being installed on the engine, the valve bridges are only loosely held in place by the rocker arm.  It is necessary to inspect each one to ensure they are positioned accurately and that none of the components have become misaligned.

While the company has always achieved accurate, 100% inspection of its engine components, the inspections had been carried out manually.  An operator would look down into the engine assembly, check each individual valve bridge for placement, and mark each one with a paint pen to indicate that it had been inspected. The process was slow and costly from a labor standpoint.  The time had come to automate.

Having successfully implemented robots in other areas of production, International felt that a robot might be useful in this case, and called on CIM SYSTEMS INC., a Noblesville, Indiana-based systems integration firm that specializes in robotic automation.  According to Tony Hillers, a CIM SYSTEMS engineer assigned to the project, a robot-guided inspection station was the perfect solution.

“We all felt that robot-guided vision would be the most flexible solution in terms of being able to automatically inspect the parts inside the engine,” he explains.  “They could have set up a little finger probe that actually touched the part to do the verification, but the parts are difficult to approach consistently.  With vision, we’d be able to avoid any problems associated with a contact approach.”

One of initial ideas for a vision system, Hillers adds, was to have 16 separate vision cameras mounted above the inspection point, allowing for one camera per part.  The problem with this approach, however, was that the engine assembly is very full with components, and wires and other parts often occlude the valve bridges.  “We needed a way to allow a single-vision camera to move in and around the engine assembly in order to actually get a look at the parts even when other things are obscuring them.  Positioning the camera with a robot allowed us to implement logic that enabled the robot arm to try to see the valve bridge from multiple angles.”  Hillers also notes that a 16-camera vision system would have been an expensive option, and would require a great deal of maintenance.

The main components selected for the project included a single Cognex In-Sight 3000 vision sensor and a six-axis ABB IRB 140 robot.  The In-Sight 3000 is a high-performance machine vision sensor that consists of a industrial-hardened, DSP-based vision processing unit, high-speed digital camera that easily mounts to the robot arm, onboard light control, built-in discrete I/O, and a pre-installed vision library of greyscale vision software tools.  The In-Sight 3000 also provides a standard VGA output for real-time display, built-in Ethernet communications, and an onboard serial port which is used to link to the ABB robot controller.

To set up the 16-point inspection routine, Hillers used the In-Sight vision sensor’s spreadsheet interface.  With the look and feel of a traditional spreadsheet, the In-Sight vision spreadsheet enabled him to quickly select vision tools and parameters from drop-down menus, and configure a customized operator interface to make day-to-day operation of the system easy for line operators, technicians, and maintenance staff at International.  “It was easy to explain how it works to shop floor personnel,“ says Hillers, “and people with no programming experience were able to make changes to the program in one day.  If you can understand Microsoft Excel even a little bit, then you can pick up on it and go with it.”

Engine blocks come into the cell on a floor-mounted conveyor, each sitting in its own nested pallet.  Once an engine is present, the IRB 140 hovers over the engine block, positioning itself this way and that so that the vision camera can get a good view of the parts.  If the camera can’t see a part, the robot repositions itself at various angles until the part becomes visible.  To increase visibility, the parts are illuminated with a combination of a ring light, which is attached to the tooling on the end of the robot arm, and side-mounted fluorescent lighting.

Once a valve bridge is in view, the robot controller sends a signal to the vision camera to capture an image of the part.  The image is then sent to the In-Sight vision processing unit, which is mounted in the robot controller enclosure, and processed with In-Sight’s PatFind™ tool, a geometric pattern-matching software tool that verifies the proper position of the part despite any occlusions or variations in part appearance that may exist.

According to Scott Hauger, a CIM SYSTEMS applications engineer who worked on the project, pattern-matching performance factored heavily into the decision to go with the Cognex system.  “The valve bridges have a unique shape, and with so many components in the way it’s critical that the vision system is able to pick out the right features,” says Hauger.  “The PatFind tool does just that”

PatFind analyzes images using geometric information in place of pixel grid-based correlation.  For example, it interprets a square as four line segments and a football as two arcs.  By analyzing the geometric information from a part’s features and spatial relationships, the PatFind tool is able to precisely and repeatably determine the precise position of each valve bridge in the engine regardless of how it appears.

As each of the 16 valve bridges is inspected, operators can view a live image display of the parts on a nearby color monitor.  The display lists the different valve bridges by cylinder number, and provides pass/fail information for each inspection.  If all 16 parts pass inspection, the engine proceeds down the production line to a testing area.  If a failure is reported, the robot controller passes the information to a line control system to be written to an RF Identification tag.  At that point, the engine goes into a repair loop where an operator manually inspects the parts in question.  It is then re-routed through the cell and inspected by the In-Sight system again.

Since the robot-guided inspection system was installed, it has been running non-stop for two shifts per day without any problems.  According to Hillers, product quality has remained consistently high, and International is pleased to add this project to its long list of successful automation stories.

Assembly line upgrade for defect elimination

120,000 automotive parts manufactured by Meister are checked each day using Cognex machine vision

Cognex Corporation (NASDAQ: CGNX), the major global supplier of vision systems, sensors and bar code readers, presents an example of an application using industrial vision in precision mechanics. Intended for automobile equipment manufacturers, the parts manufactured by Meister France are subjected to very strict appearance checks with the aim of completely eliminating defective parts before delivery to customers. An ambitious gamble when you are producing almost 40 million parts per year. A gamble which has paid off thanks to Cognex In-Sight® industrial vision sensors.

The Meister Group is a Belgian industrial group mainly supplying the automobile market. The company has factories in Belgium, France and the Czech Republic specialising in the mass production of cut steel parts.
The challenges for these modern production units, which use specialist precision lathes, is to manufacture relatively complex parts in a few seconds, and to guarantee the conformity of the parts on delivery, without ignoring the essential and continual search for gains in productivity.

In France, the Meister factory is located at Scionzier, in Haute-Savoie. It manufactures electric valve parts for automobile equipment manufacturers specialising in ABS braking systems. Nearly twenty-four multi-spindle lathes produce 120,000 parts each day, representing an annual production of 35 to 40 million parts.

The demand for quality is the main problem on which all of its efforts are concentrated: it has to try and avoid delivery of defective parts to customers. In a sector where the smallest incident on an assembly line can bring about exhaustive investigations and can lead to complicated and costly procedures for the subcontractor, the search for Zero Faults is the only acceptable way forward.
However, the manufacturing techniques used and the demands of mass production do not allow such an objective to be reached directly from the use of machines. Checking and sorting has to be carried out in order to remove defective parts, with the faults consisting of missing components, metal shavings, loose components, damage from vibration or knocks…

Checks were previously carried out by the naked eye by operators which limited the number of defective parts to around 1 in a 1000. This was still too many, and so studies had to be carried out in order to reduce this rate as a value lower than 100 ppm was aimed for. It was also necessary to work on reducing the impact of manpower costs on the cost price of the parts.
Considering the automation of these checks by vision tools was a natural approach for Meister’s technicians, who already had experience of industrial vision systems for a dimension checking application. A seminar organised by the Alpsitec company also allowed them to find out about the performance and capacities of the In-Sight vision sensors, made by Cognex, the world leader in industrial vision.

Alpsitec is an approved partner system integrator of Cognex. The company was called upon to carry out a demonstration directly on the production line so as to verify that the Cognex cameras were capable of “seeing” the faults they had to detect. After this first feasibility test, a prototype was brought up to date and assessed over a month. The simplicity of the use of the In-Sight sensors was a decisive factor in the choice of the system. The Terms and Conditions were drawn up and two test systems were ordered.

The checking system – in fact two independent test benches – was installed at the end of the production line in order to carry out a final check of the parts just before they were packed. All the parts produced were sent to this control point, therefore 100% of the production is checked.

The parts are put into their packaging – the mesh – by a robot. Once the packaging is completed, the robot picks it up and places it on the test surface. Then the robot takes hold of the Cognex In-Sight 1000 vision sensor linked to a lighting system and passes it along the mesh, over the parts. It’s important to remember that the vision sensor must inspect each part in order to detect any of the four types of faults to be removed: presence of metal shavings, missing components, loose components, and damage from knocks or vibration. The sensor sends information on the checks carried out to the robot’s control centre. The robot puts the vision sensor down and takes the defective parts and deposits them into a chute – one chute for each type of fault – which then carries them to a hopper. Then the system continues its operation.

One of the test benches is fitted with two In-Sight 1000 vision sensors and operates at a rate of 6000 parts per hour. The other system comprises a single sensor and works at a rate of 4000 parts per hour. Both systems worked as dual sorters during the first few months of the operation.

The important part of the work of updating the application consisted of identifying the various faults which the checking systems had to recognise and to “teach” them to the vision sensors. This procedure is essential for optimising the efficiency of the checking system.

The rate of faulty parts delivered to customers has rapidly dropped to 40 per million. The power of the processor algorithms of the In-Sight sensor and the finer analysis of the faults to be removed should allow this rate to be brought down even more to below 20ppm.

Jean-Marc Sermet, Technical Director of Meister France, has supervised this project from beginning to end. He is very pleased with Cognex products and Alpsitec’s service, the combination has provided him with the necessary skills and experience in setting up vision solutions in industry. “Above all, we are engineers specialising in precision metal cutting”, stated Mr.  Sermet. “Alpsitec’s contribution has allowed us to make rapid progress on this project and to benefit from efficient and reassuring support.”

Alpsitec has also trained a technician who has been able to rapidly take charge of setting the vision sensors’ parameters. So Meister is able to input data by itself for new types of faults to be learned and for modifying the parameters in relation to the 15 different types of parts to be inspected.

“We were concerned that these test systems would slow down production rates. We have noted with satisfaction that the implementation of these industrial vision solutions do not have a negative effect on production”, added Jean-Marc Sermet. “The solution used appears to be particularly stable, and the operators do not have any need to intervene.”
The biggest reward is that there has been a real return on investment in less than six months. Customer relations have been strengthened from the significant improvement in quality. Meister is currently looking at other applications for industrial vision on its production lines.