The approximately 130,000 spot welds in a vehicle’s chassis are subject to regular checks. Here, each weld has to satisfy 29 quality-assurance criteria, including resistance, strength, and consistency. After all, welding robots aren’t always perfect and can sometimes put a weld in the wrong place. Spot welds can also become brittle.
Previously, the process involved creating elaborate 2D quality-control plans on paper. These contained all the information the tester required, for example which spot welds were located where. This was a laborious practice, as the information had to be retrieved from a number of different sources. After inspecting the spot welds – in other words actually cutting each one – the results were recorded by hand. This produced a 1.2-metre high, 24-kilogram pile of paperwork for each vehicle model, and anyone familiar with german car manufacturers knows how many vehicle models the manufacturer has. The issues here are plain to see: an enormous amount of time was needed for documentation, human error was inevitable, and hours of researching records were required in cases where a certain spot weld was subsequently found to be faulty.
Tapping into digital sources automatically
The german car manufacturer has been using the Teamcenter Product Lifecycle Management system since 2007, where it stores data for each vehicle for the next 20 years – from the development idea right up to the finished product. The powerful solution is operated in Wolfsburg in 120 server racks with connected databases and is being continually expanded. Some 43,000 employees around the world have access to the PLM system.
“Considering that the information we require from the various sources is already available in Teamcenter in digital form, we concluded that this information could be used for an automated quality-assurance process. The digital solution was born,” explains PITERION.
Goal: User-friendly workflows
Looking to achieve substantial improvements and a significant increase in efficiency, PITERION began working together with the german car manufacturer to develop user-friendly workflows that would then be digitalized and integrated into Teamcenter. One of the major tasks during the next stage was to translate all heterogeneous data sources and systems into a quality-control workflow. This included data from product development, parts lists for the chassis elements, work or production plans, as well as machine planning information containing incredibly varied data such as CAD drawings or Excel lists.
The digital solution Admin and Manager
Despite the broad range of features available in Teamcenter, in this case it was necessary to develop two new modules. These would extract the required information from the correct data sources and present it via two easy-to-use interfaces – Admin and Manager – for quality-control planning and execution. The core tasks regarding the welding type and technique, quality criteria, and testing methods are created in Admin.
The Manager is used for creating testing plans, for defining what a test should cover and the criteria involved, for starting workflows, visualizing spot welds, and displaying the test results in a matrix. A rights management system can be used to determine who can do what in the Manager.
“SCRUM appeared to be the most promising method for project management, as it allowed us to develop initial prototypes very openly with different SCRUM teams from IT and other specialist departments. These were then developed further in regular SCRUM sprints,” reports PITERION.
The digital solution optimizes quality and saves time
The resulting workflow uses an easy-to-understand 3D model of the product structure. It provides testers with exact instructions on which spot welds to test and where, as well as how to proceed if there are no problems or in cases where certain spot welds are faulty. The test report is displayed as a 3D model where each spot weld is allocated a color according to the traffic-light principle. By clicking on a spot, testers can obtain all the necessary test results for that weld.
In addition, for very similar parts where 80 percent of the spot welds are identical, the system only needs to test the 20 percent that are different. This is a further factor that vastly improves efficiency. Should several deficiencies be determined in a certain area, then the workflow ensures that the welding process itself is checked. For example, perhaps the robot is being set up incorrectly and is therefore not working to the required accuracy.
Set for international rollout
The digital solution is currently being used by 120 employees to test spot welds at three European sites. There are plans to roll out the solution globally at all sites and to make it available on mobile devices. Further items such as screws, rivets, and adhesives are also set to be included in the quality management process.
PITERION is an international PLM service provider headquartered in Germany with branches in the USA, India, Tunisia, Sweden, Switzerland and Poland. Our highly qualified staff offers solutions and services independent of system manufacturers. We always follow the provisions of the EN 9100 (aerospace), ISO 9001 and ISO 14001 quality management standards. We have set up internal standards and processes that enable us to maintain a consistently high quality of service across our sites throughout the world.
We constitute a competent and independent partner of our customers providing tailor-made solutions and services. Jointly with our technology providers we may therefore support the PLM strategy of our customers in the best way possible.