Painting Simulation

Multiphysical simulation of a high rotation atomizer with contact charger to calculate the droplet trajectories, in this example, to the chassis of a Volvo V60.

Fully automated Paint Booth

In many industries, well over half of all components are now painted manually simply because of the number and variety of options. The fully automated paint booth will enable the processing of any object in batch sizes of one.

Self-programming Paint Booth for Batch Size One

Project SelfPaint

The programming of a fully automated painting robot is still very expensive using current painting technology. In the "SelfPaint" project we are creating a new self-programming paint booth in cooperation with Fraunhofer Institute for Manufacturing Engineering and Automation (IPA) and the Fraunhofer-Chalmers Research Centre for Industrial Mathematics (FCC) in Sweden.

 

Aims 

The aim of the Fraunhofer research project is to develop a painting booth within three years (2016-2018) that independently and cost effectively scans, measures, and paints an object.

The fully automated paint booth will be capable of processing customized objects that are 1x1x2 m³ in size. This innovation will be suitable for many industries and applications.

Schematic representation of the 3D scanning process
© ITWM

Schematic representation: 3D scanning process, in this example for a chair.

Schematic representation
© ITWM

Schematic representation: Scan data are used as the basis for a fluid dynamic simulation.

Schematic representation
© ITWM

Schematic representation: Painting the component, in this example, a chair.

Steps for Optimal Painting

Automated painting is a five-step process:

  1. First, a three-dimensional scan of the component is performed.
  2. Data from this scan forms the basis for a fluid dynamic simulation: Simulation software plots the trajectory of the paint particles and then determines the optimum volume of paint and air needed to achieve the required coating thickness.
  3. The system takes the simulation data to plan the most efficient robot path for the painting process. The optimal painting paths in the processing line are determined using intelligent algorithms and precise fluid dynamic flow simulations. Machine learning methods are used to optimize the path.
  4. The component is painted.
  5. Quality assurance check: Is the required coating thickness achieved?

Our part in the joint project is the three-dimensional scan of the component and the qualitiy assurance check with terahertz technology afterwards.

 

Three-Dimensional Object and Position Detection

In order for the painting cell to know the position of the object for simulation and painting, it must be recorded in three dimensions. The self-programming painting cell uses 3D sensors that were originally developed to control video games - a global mass market. The accuracy of the position detection is more exact than the deviations of common components from the CAD data and is therefore within the manufacturing and positioning tolerances. This high resolution is made possible by tailor-made algorithms for data processing. 

 

Terahertz Technology for Quality Control

In the final process step of automated painting, the quality is checked: Is the thickness of the coating as desired? For this quality-control we use terahertz waves. With this technology developed by us wet and coloured lacquers can be measured without contact. The quality of the paint layers can already be checked during or after the painting process. Substrates - the basis of the coating layers - do not have to be metallic, but can also consist of other materials.

Schematic representation
© ITWM

Schematic representation: Quality checked via terahertz technology.

Modules

Separate modules in the automated paint booth enable:

  • an optical 3D scan of the object to be painted,
  • computer-aided optimization of the painting process, and
  • a non-contact check of the finished coating thickness.

Advantages of the "SelfPaint" Technology

  • Enables automated painting of small lots and even customized work pieces, the so called batch size 1.
  • Achieves up to 20 percent savings in paint and reduces solvent emissions by 20 percent.
  • Consumes 15 percent less energy.
  • The operation is five percent faster than conventional manual painting.
  • Reproducibility of the painting operation: In contrast to a human, a machine or a robot always applies the same amount of paint – and, in the ideal case, this is even automatically documented.
  • The automation of painting processes represents an opportunity to return production operations to Europe and Germany and it even increases job safety in the process.

 

Partners and Responsibilities