White Body ED Verification by CAE

White Body ED Verification by CAE with Acura TL Trialed Ray Hughes Vehicle Structure Gerhard Zelder CADFEM GmbH Engineering Steven Junor CADFEM US

Introduction to ED Coat Automotive white bodies are coated at manufacturing facilities throughout the world using electrostatic paint systems to deposit paint onto metal surfaces. Automotive paint application involves a multi step process which is comprised electrodeposition coating, and various spray applications. ED-Coat Line ED-Coat Bake Sealer Line Sealer Bake Spray Lines 2

Automotive Paint is comprised of 5 separate and distinct layers Paint Coating Layers Function Clear Coat Gloss & Weatherability Base Coat Color Primer SurfacerSurface Preparation ED Coat Provides Corrosion Protection Pre Treatment Substrate Provides Surface Adhesion 3

White Body ED Coat Processing ED Coat Line From Pre Treatment Typical E Coat System To ED Coat Oven + - Anode Cathode 4

Corrosion Protection Considerations Low ED Coat coverage can result in poor corrosion performance in the market. Examples (Honda Models) Rear Wheel Arch Hood Panel Door Panel Tailgate Side Sill Frame Member White Body structures should be designed with consideration for sufficient ED Coat coverage to prevent corrosion. 5

Typical ED Coat Confirmation Process Three White Bodies are required to confirm adequate ED Coat coverage during each program development. This process is labor intensive and expensive due to the high cost of prototype white bodies. Prototype DWG-1 Prototype Lot-1 Prototype DWG-2 Prototype Lot-2 MP DWG MP Try-1 White Body Tear Down White Body Tear Down White Body Tear Down ED-Coat Thickness Confirmation ED-Coat Thickness Confirmation ED-Coat Thickness Confirmation 6

ED Coat Confirmation Process Using Simulation (Concept) Simulation confirmation will be conducted before finalizing prototype drawings. By using simulation, only one White Body is required to confirm adequate ED Coat coverage during each program development. Prototype DWG-1 Prototype Lot-1 Prototype DWG-2 Prototype Lot-2 MP DWG MP Try-1 White Body Tear Down White Body Tear Down White Body Tear Down ED-Coat Simulation Confirmation ED-Coat Thickness Confirmation ED-Coat Thickness Confirmation ED-Coat Thickness Confirmation 7

Benefits of Electrocoating Simulation Reveals what's happening inside a body in white structure. Find critical regions with high risk for corrosion. Simulate changes to local geometry to improve coating performance. Analyze different voltage curves used at the factory. 8

Simulation Inputs White Body CAD Data BIW DPM Data Reduced or Complete BIW Model (Reduced Shown) Paint Panels Properties C B A Front surface Anode Conductivity Throw Power Thickness [µm] 30 25 20 15 10 Phosphated Galvanized Steel, 32.50 C A front A back B front B back C front Hidden surfaces Viscosity % Solids 5 0 0 50 100 150 200 250 300 350 Position [mm] Gap ED Line Parameters and Layout Anode Locations Tank Dimensions Tank Volume Voltage Conveyer Speed Bath Temperature Dwell Time 9

Simulation Inputs White Body CAD Data BIW DPM Data Reduced or Complete BIW Model (Reduced Shown) Paint Panels Properties C B A Front surface Anode Conductivity Throw Power Thickness [µm] 30 25 20 15 10 Phosphated Galvanized Steel, 32.50 C A front A back B front B back C front Hidden surfaces Viscosity % Solids 5 0 0 50 100 150 200 250 300 350 Position [mm] Gap ED Line Parameters and Layout Anode Locations Tank Dimensions Tank Volume Voltage Conveyer Speed Bath Temperature Dwell Time 10

Simulation Inputs White Body CAD Data BIW DPM Data Paint Panels Properties C B A Front surface Anode Conductivity Throw Power Thickness [µm] 30 25 20 15 10 Phosphated Galvanized Steel, 32.50 C A front A back B front B back C front Hidden surfaces Viscosity % Solids 5 0 0 50 100 150 200 250 300 350 Position [mm] Gap ED Line Parameters and Layout Anode Locations Tank Dimensions Tank Volume Voltage Conveyer Speed Bath Temperature Dwell Time 11

Simulation Inputs White Body CAD Data BIW DPM Data Simulation Results Paint Panels Properties C B A Front surface Anode Conductivity Throw Power Thickness [µm] 30 25 20 15 10 Phosphated Galvanized Steel, 32.50 C A front A back B front B back C front Hidden surfaces Viscosity % Solids 5 0 0 50 100 150 200 250 300 350 Position [mm] Gap ED Line Parameters and Layout Anode Locations Tank Dimensions Tank Volume Voltage Conveyer Speed Bath Temperature Dwell Time 12

How does it work? To predict the film thickness on a substrate, VPS/EDC uses iterative and time dependent calculations of paint deposition Anode O 2 H + H 2 U= e - e - O R-COO - R-COOH + N H H 2 O H 2 OH - N Cathode (Car Body) Current density: Deposition rate: Thickness: Surface resistance: Throwing Power Description Equations to describe ED Coat J J ( R S ) s d s(j ) d s dt R R d) S S ( Process time t 13

Post processing can verify film thickness at any BIW location VPS/EDC User Interface Time History Time Step Progression Tabular Results 14

Simulation Processing Timetable Complete BIW Model Simulation Flow ~ 8 Weeks Meshing and Simulation (6 weeks) Review Results Design Optimization (2 weeks) Reduced BIW Model Simulation Flow ~ 6 Weeks Meshing and Simulation (4 weeks) Review Results Design Optimization (2 weeks) 15

White Body ED Verification (2 Step Process) Step 1: Throwpower Box Simulation (Simple Structure) Step 2: Complete White Body (Complex Structure) TP Box Simulation Results 16

White Body ED Verification (Step 1) Throw Power Box Simulation (Simple Structure) A Throw Power Box is used to confirm acceptable ED-Coat. Throw Power or Film Thickness is being achieved during ED- Coat processing. 7 30 790 60 15 TP Box DPM TP Box Simulation Results Point Distance From End (mm) Point 1 5 Point 2 15 Point 3 25 Point 4 35 Point 5 45 Point 6 55 Point 7 65 Point 8 75 Point 9 85 Point 10 95 Point 11 105 Point 12 115 Point 13 125 Point 14 135 Point 15 145 CADFEM successfully predicted the film thickness for 15/15 measurement points for the Throw Power Box Requirement: Must be within +/- 3 microns of actual measured paint thickness values (Industry Standard) 17

White Body ED Verification (Step 2) Acura TL Reduced White Body (Complex Structure) Exterior White Body A-Pillar Side Sill Rear Wheel Arch Simulation Accuracy Summary Exterior A-Pillar Side Sill Wheel Arch Total VIRTUAL PAINT SHOP 53/53 15/15 18/18 16/16 4/4 CADFEM successfully predicted the film thickness for 53/53 measurement points for Reduced White Body Structure Requirement: Must be within +/- 3 microns of actual measured paint thickness values (Industry Standard) 18

Summary/Conclusion ED Coat is applied as a means to inhibit corrosion to white body structures. Simulation methods have been developed to predict the thickness of ED Coat on complex structures inside the BIW. Based on the results from a recent trial, CADFEM has demonstrated that their VPS/EDC software is capable of predicting ED Coat paint thickness in BIW structures. ED Coat Simulation is a valuable tool that provides a means to balance the performance of Corrosion, NV, and Crash before setting final specifications to a BIW structure. 19