Edited by Bruce Walton
When it opened its Wrzesnia, Poland, plant in late 2016 – less than two years after launching construction – Volkswagen (VW) had two goals: build VW Crafter delivery vans and push automotive manufacturing technology limits.
“The plant in Wrzesnia is a role model for European transporter construction – state-of-the-art technology yet environmentally efficient at the same time,” plant CEO Jens Ocksen explains.
Configurable vehicle bodies and equipment variants are key to commercial vans, so VW officials planned for 70% of Crafter production to be made-to-measure solutions, requiring extensive automation at the plant. To implement the wide range of variants and individual orders, 430 robots carry out 68% of welding and gluing procedures in the body shop as well as material transport tasks. The automation level in the paint shop is 65%.
Quality assurance challenge
Given the 1,100 equipment variants of VW Crafters that can be configured, the range of parts to be measured is vast: underbody, front end, closed and open bodies, single-cab, double-cab, etc. To accommodate high-volumes of parts and vehicles requiring measurement, VW plant designers built a 58,000ft2 (5,400m2) measuring hall, integrated into the body manufacturing line close to production.
German metrology equipment supplier GOM, represented in North American by Capture 3D, has several systems in the facility – two Series 6 ATOS ScanBox systems, three double robot measuring cells, and several mobile optical measuring machines. The machines inspect assembly modules and body shells through to completely painted bodies. Everything is designed for measuring vehicles up to 23ft (7m) long and almost 10ft (3m) tall. Optical systems offer 3D geometry checks, including border lines and hole pattern by comparing nominal and actual data.
With the variety of the components to be measured, metrology is a difficult-yet-vital task at the plant. Robot paths and sensor positions need be calculated automatically and independently from the user and not block running measuring cells.
GOM software tools, such as virtual measuring room (VMR) and auto teaching, support high measurement volumes for VW. In the VMR, components, sensors, measuring cells, and kinematics are simulated so paths and positions of the robot and the sensor can be calculated automatically. Component CAD files provide the basis for determining the measuring positions. Inspection planning can take place on a decentralized basis regardless of the measuring system. Measuring and inspection programs are stored as templates and called up by employees at measuring cell kiosks.
VW engineers refer to GOM’s measuring systems as fast runners, and they allow suppliers near the plant to measure their components in the plant’s measurement hall. Because the location in Poland was planned without a stamping plant, suppliers of pressings and add-on parts must prove part tolerance using the same systems VW uses.
In the body shop, 6 in-line Zeiss Industrial Metrology robot measuring cells check individual points, hole positions, and edges. Optical measuring results are used for process monitoring by correlating data between measurements. The systems detect unusual fluctuations but cannot perform fault analysis. Comparing process data to results from the measuring hall allows targeted conclusions about actual causes of process nonconformity.
Werner Steinert, head of measuring systems at the Wrzesnia site, says the switch from tactile measurement to optical systems allows for a more comprehensive picture of the production process.
“The optical measuring room is the measuring room of the future – for people and technology,” Steinert says. With more than 25 years of experience in automobile construction, he says the need for quality data is more important than ever, because, “Uncontrolled processes are bad processes.”
Non-contact and full-field coordinate measuring technology offers VW more information. The 3D measuring results provide effective feedback control without taking up more time for the product. They also check the function, visual appearance, and design based on dimensional accuracy, achieving exacting quality requirements.
Capture 3D Inc.
Zeiss Industrial Metrology