Apparatus for applying conformal coatings to electronic circuit boards

Apparatus for producing a conformal coating for application to non-uniform substrates having varied surface contours, said apparatus comprising:

• a slot nozzle having an elongated slot outlet through which a conformal coating material can be extruded;
• a valve for starting and stopping a flow of said conformal coating material to said slot nozzle to produce discrete conformal coatings;
• at least one air slot proximate said elongated slot outlet for impinging at least one air stream onto said conformal coating material exuding horizontally from said elongated slot outlet and for carrying said conformal coating material in a film to a non-uniform substrate surface;
• a valve for starting the flow of air prior to extrusion of said conformal coating material from said elongated slot outlet, and further including a shim in said slot nozzle, extending at least to said elongated slot outlet, for dividing said elongated slot outlet into a plurality of slot outlets from which said conformal coating material is extruded.

Apparatus for producing a conformal coating for application to non-uniform substrates having varied surface contours, said apparatus comprising;

• a slot nozzle having an elongated slot outlet through which a conformal coating material can be extruded;
• a valve for starting and stopping a flow of said conformal coating material to said slot nozzle to produce discrete conformal coatings;
• at least one air slot proximate said elongated slot outlet for impinging at least one air stream onto said conformal coating material exuding horizontally from said elongated slot outlet and for carrying said conformal coating material in a film to a non-uniform substrate surface;
• and
• a valve for starting the flow of air prior to extrusion of said conformal coating material from said elongated slot outlet wherein said slot nozzle has an extrusion channel terminating in said elongated slot outlet disposed along said channel and through which said conformal coating material moving through said channel is extruded;
• and
• means in said channel, extending at least to said elongated slot outlet, for dividing said elongated slot outlet into a plurality of elongated slot outlets from which said conformal coating material exudes;
• wherein said conformal coating material extruding from each said elongated slot outlet merges into said conformal coating material extruding from adjacent elongated slot outlets to form a continuous coating web prior to impingement of air thereon.

Apparatus for producing a conformal coating for application to non-uniform substrates having varied surface contours, said apparatus comprising;

• a slot nozzle having an elongated slot outlet through which a conformal coating material can be extruded;
• a valve for starting and stopping a flow of said conformal coating material to said slot nozzle to produce discrete conformal coatings;
• at least one air slot proximate said elongated slot outlet for impinging at least one air stream onto said conformal coating material exuding horizontally from said elongated slot outlet and for carrying said conformal coating material in a film to a non-uniform substrate surface;
• a valve for starting the flow of air prior to extrusion of said conformal coating material from said elongated slot outlet wherein said slot nozzle comprises a slot nozzle die having die faces defining an elongated channel for receiving and passing said conformal coating material therethrough;
• said elongated channel terminating in said elongated slot outlet;
• a shim disposed between said die faces in said channel, said shim having a plurality of elongated projections defining slots therebetween,
• said projections extending to said elongated slot outlet and defining between them at the ends of said slots defined by said projections a plurality of slot outlets through which said conformal coating material is extruded in a plurality of separate streams which merge to form said film of said conformal coating material.