In the printed circuit bord business dip coating typically is used to coat flexible inner layers and thin outer layers. Other sectors than PCB manufacturing do coat metal plates or metal foils. In fact any coating process where highest cleanness is required dip coating will be chosen. A typical example is coating of glas bars for measuring tools. Dip coating combines many advantages. The fact no special made coating tool is needed allows particular machine properties:
From small to medium sized coating capacities.
The maximum output can be increased by dipping more than one panel in the same time. Depanding on the product withdrawal and drying will limit the maximum output capacity. However up to 150 panels per hour are possible.
Uniform coating thickness ± 1 µm.
Coating thickness can be varied simple and clearly (e.g. 7 µm to 12 µm) just by changing the withdrawal velocity.
To get reliable and continously good quality only very few and easy to handle parameters need to be controlled. (Viskosity, temperature, withdrawal velocity).
No coating tool is required!
To cover or to fill holes or gaps within a well defined range is not a big challenge using an adequate resist. (State of the technology)
Coating electrolytic galvanized 3-D structures is possible. (State of the technology)
Thin panels can be coated without limitation. (State of the technology)
Flexible boards which ar not planar a 100% can be coated without any quality loss.
If specified even thick panels (e.g. 4 mm) can be coated. ( five sides)
Basicly dust and aerosols can be reduced to a minimum by the right machine concept and well selected coating and drying modules.
Especially for laser direct imaging (LDI) with highly collimated laser light it is a must.
Suiteable resists are made to be used and kept in dipping systems for month without any cleaning efforts.
Compared to roller coaters costs for maintenance and usage are very low.
The compact construction reduces the required spot.