Case Study C

E-coat Paint Process Simulation using Finite element analysis

Case Studies
The following case studies are meant to be representative of the many different types of investigative work that can be accomplished by Finite Element Analysis (FEA) with the Parametric Module. These include examples from rocker panel design optimization to visualization of the E-coat paint process in operation.

Several PC work stations were used to create and run simulations for the case studies, including a Dual Intel Xeon 3.06 GHz PC with 4.5 GB RAM and an Intel Pentium 4 3.06 GHz with 1.5 GB RAM.

The typical elapsed time per iteration was related as a function of the total number of elements and the number of Boundary Conditions. The range of time required for one iteration varies from < 20 seconds for the simpler models to as much as ~25 minutes for the larger ones.

Case Study C:
Can Quality be Improved by Adding ME Cells to the Tank?

A paint process engineer is investigating how to increase the E-coat film thickness on the roof of one of several models that the plant produces. The E-coat paint system already has Side and Floor Membrane Electrode Cells. The addition of Roof ME Cells is simulated.

Present profile Cells

Situation
200 V @150 seconds.

Roof E-coat film target is 17 µ and the current thickness is ~1 – 2 µ less.

Model
One model was created incorporating the present situation as well as future Roof ME Cells. Only ½ of the car is modeled due to a symmetry plane that runs parallel to the long axis of the vehicle, and creating both identical sides is an unnecessary complication. This model is a cross-sectional representation of the car in the paint bath, created in a 2D format which is then extruded to create a pseudo-3D model. The advantage of this approach is quick model preparation and extremely fast solution times. Note this model also includes a very deep recessed region and so it will simulate current to flow into the region just like an actual 3D model would, but without the complexity and longer solution times.

Voltage profile with Roof ME Cells	E-coat film thickness w/Roof ME Cells

Results
The roof average E-coat film thickness was increased to over 17 µ by the addition of Roof ME Cells. The maximum E-coat thickness did not increase, and there was better coverage in the recessed portion of the door. When comparing the before and after voltage profiles, the addition of Roof Cells pushes the electric potential into a more acceptable area.

Conclusion
The simulation showed that the E-coat film distribution can be improved by adding Roof ME Cells. While it was not previously stated as a problem, the thickness of the paint on the exterior of the door was probably too great. The next phase of the simulation is a fine-tuning project trying to lower voltages to reduce the exterior maximum on the door while still maintaining the minimum film build in the recessed regions.

Case Study A    |    Case Study B    |    Case Study C    |    Case Study D    |    Case Study E    |   Case Study F