BMW F11 Service Training page 12

F11￿Body.
2.￿Body.
Overlapping￿layers￿of￿sheet￿metal￿in￿dry￿areas￿are￿sealed￿where￿necessary￿to￿prevent￿dust￿from
entering.
Contact￿is￿avoided.￿between￿different￿types￿of￿materials,￿which￿are￿critical￿in￿terms￿of￿corrosion.￿The
combination￿of￿material￿substrates￿and￿joining￿procedures￿is￿matched￿carefully￿to￿prevent￿corrosion
risks.
Coating￿process
During￿the￿painting￿process￿the￿body￿shell￿is￿immersed
• in￿an￿alkaline￿bath￿for￿cleaning
• phosphated￿(surface￿roughened￿up￿for￿better￿adhesion)
• coated￿using￿a￿catalytic￿immersion￿process￿(coated￿with￿corrosion￿protection￿paint￿on￿inside
of￿all￿hollow￿body￿cavities).
The￿organic￿finish￿paint￿is￿then￿baked￿on.
Moreover￿the￿body￿is￿sealed￿with￿PVC￿and￿the￿outer￿surface￿protected￿with￿filler,￿top￿coat￿and
transparent￿paint.
Particularly￿critical￿body￿areas￿on￿the￿F11￿are￿protected￿by￿systematic￿hollow￿cavity￿preservation.
The￿objectives￿are:
• Five￿years￿without￿any￿visible￿corrosion￿to￿the￿body￿surface
• Three￿years￿without￿any￿visible￿corrosion￿in￿the￿underbody￿area
• Twelve￿years￿without￿any￿panels￿rusting￿through
• Seal￿against￿water￿and￿dust
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