Enameling Technology

Interaction of electrostatics and fluid mechanics in the production of thin powder coatings

The numerical flow calculation program, developed to a more advanced stage for the simulation of powder coating processes, has provided an accurate representation of electrostatic influences in the coating of flat sheet metal in relation to the coating thickness distribution and the coating efficiency. 

 

Summary

In order to prevent solvent emissions, powder coating is increasingly used in the coating industry as a more up to date and environment-friendly alternative to wet lacquering.  The growth in potential applications for this technology, in the automobile industry among other sectors, has led to a sharp increase in the stringency of requirements for the visual quality and reproducibility of powder coatings in recent years.

Given this context, this project involved the development of experimental and numerical methods to predict the dispersion of powder particles between the spraying device and the object to be coated.

To this end, a numerical flow calculation program has been extended to allow the additional consideration of electric field strengths affecting the movement of particles and the space charge.  Calculated values have been compared with data derived from experiments using optical measuring devices.

Results:

Using the calculation program, it has been possible to determine the resulting coating thickness distribution and coating efficiency for the coating of flat sheet metal with sufficient accuracy, on the basis of flow conditions in the powder spray gun.  This has a number of associated advantages:

  • Process simulation without the need for expensive experimental investigations
  • Improved cost-effectiveness associated with minimal coating powder consumption
  • Improved operational reliability of the overall coating process
  • Scope for parametric analyses for the further improvement of spray gun and nozzle technology.

More Project Informations

Project title:  Interaction of electrostatics and fluid mechanics in the production of thin powder coatings

Project number:  01RV9619/8

Project period:  1996 - 1999

Project region:  Germany (Bavaria)

Project contact:

Herr Prof. Dr.-Ing. habil Sommerfeld

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Source: German National Library of Science and Technology Hannover (TIB)