How to control viscosity with Dip Coating Equipment
Dip coating is one of the most efficient ways to apply conformal coating. While it can be done manually, dip coating is usually done with automatic equipment to greatly increase the amount of consistency within the process as well as lower labor costs. Dwell time is a vital factor to control the thickness of the coating as well as controlling the amount of material usage. The optimum dwell time for a particular board design should be determined by varying the withdrawal rate with viscosity of the conformal coating material.
There are two methods for controlling viscosity with conformal coating materials and dip coating applications.
The first is flow cup control, which is a manual process. A cup of known size with a hole in the center is filled with the conformal coating and the time for the material to run out is related to viscosity. This is reasonably accurate and normally is suitable for most applications.
An alternative is inline, automatic viscosity control of the conformal coating where the solvent evaporation and material top up is controlled by a viscometer controlled system. This is extremely accurate and removes all of the manual processes involved in testing with a flow cup.
Whether by using an automated, inline viscosity control system or manual flow control cups, controlling viscosity in your dip coating equipment is vital to a successful coating project.