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Geometry and Motion Planning

Virtual Paint Shop - Spray Painting

Car fender

An innovative software for simulation of spray painting in automotive paint shops has been developed. The software is based on research within the MERA and FFI programs funded by Vinnova. Our research partners are Volvo Cars, Saab Automobile, Scania, Volvo AB and Swerea IVF.

Paint and surface treatment processes in the car paint shop are to a large extent automated and performed by robots. Having access to tools that incorporate the flexibility of robotic path planning with fast and efficient simulation of the processes is important to reduce the time required for introduction of new car models, reduce the environmental impact and increase the quality.

The combination of high physical complexity, large moving geometries, and demands on near real time results constitutes a big challenge.

In spray painting paint primer, color layers and clear coating are applied through the Electrostatic Rotary Bell Sprayer (ERBS) technique. Paint is injected at the centre of a rotating bell; the paint forms a film on the bottom side of the bell and is atomized at the edge. The droplets are charged electrostatically and driven towards the target car body both by shaping air surrounding the rotating bell and by a potential difference in the order of 50-100 kV between paint applicator and target.
 
To efficiently simulate this demanding application we have developed an immersed boundary octree flow solver, IBOFlow, based on algorithms for coupled simulations of multiphase and free surface flows, electromagnetic fields, and particle tracing. In the software IPS Virtual Paint, the IBOFlow solver is included in the in-house package for automatic path planning, IPS. Agreement with experimental data for test plates is excellent.

The major improvement of computational speed compared to other approaches is partly due to the use of grid-free methods which in addition simplifies preprocessing.

A full scale industrial application like painting the trunk lid of a car is accomplished in the order of an hour on a standard PC. Therefore the simulation tool can be useful for paint prediction and troubleshooting in the design stage as well as in off-line programming of paint robots.

Animations

Spray painting of a car hood using IPS Virtual Paint.

Spray painting of a car side using IPS Virtual Paint.

Images

  • Car fender
  • Fender validation
  • Fender validation
  • Trunk Lid Mesh

Downloads

Keywords

Computational fluid dynamics; Electrocoating; Heat transfer; Multiphysics; immersed boundary method; Coating; Multiphase flow; E-coat; High performace computing; Surface treatment; Spray painting;

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