Abstract:
Apparatus and methods for producing intermittent, discrete patterns of coating material onto discrete irregular substrate areas, such as electronic circuit boards, where the patterns have sharp, square leading and trailing edges, as well as side edges. A slot nozzle die has elongated air slots along the slot extrusion opening. In the operation of the apparatus, the air flow is initiated from both air slots prior to the initiation of the coating material flow. Also, the air flow is continued beyond that point in time, when the coating material flow ceases. The delays between the operations of the air flow and the hot melt flow are on the order of micro seconds. Alternatively, the lead and lag air start and stop times on each side of the film of coating material are different to control the exact disposition of the square cut-on and square cut-off coating edge on the circuit board. The air flow carries the film coating material to the circuit board for deposition in discrete areas thereon. The sharp cut-on and cut-off accommodate multiple discrete area coating or multiple automated circuit board coating.
Abstract:
Apparatus and methods for spray coating selected areas of a circuit board with an insulative coating material without coating regions of the circuit board to be left uncoated. A liquid spray device emits the coating material and an air assist attachment connected to the liquid spray device directs jets of air into impinging relation with the coating material emitted therefrom to transform the coating material into an atomized, shaped spray pattern for coating the selected areas. The air assist attachment can be disabled so that the spray device transforms the coating material into a non-atomized, shaped spray pattern for coating selected areas without coating regions of the circuit board to be left uncoated.
Abstract:
To make housings used in automotive engineering for holding electronic components suitable for engine compartment installation, complex measures are taken that involve high manufacturing costs. In accordance with the invention, a housing is provided that permits simple production at low cost and affords dependable protection of the electronic systems, in that the electronic components mounted on an electronic carrier are provided with a protective lacquer, and then covered with a flexible and watertight foil as a protection against moisture in such a way that it provides an airtight and watertight seal on an all-round edge formed by a metal plate supporting the electronic carrier. A housing cover forming the housing in conjunction with the metal plate serves as a mechanical protection.
Abstract:
A method of applying a conformal coating to a printed circuit board and components attached thereto while leaving selected components attached thereto uncoated, comprises the steps of providing a printed circuit board having a multiplicity of components attached thereto, including selected components that are not to be coated; enclosing the selected components within conductive protective enclosures sized to enclose the selected components therein and thereby protect those components from the intrusion of conformal coating material, the enclosures having sufficient electrical conductivity to discharge electrostatic charges therefrom when one of the enclosures is contacted by an electrically conductive medium, thereby protecting the components attached to the printed circuit board from damage due to the discharge of electrostatic charges from the enclosures; applying a conformal coating to the printed circuit board, thereby conformal coating the enclosures and the components which are not protected by the enclosures; and removing the coated enclosures from the selected components.
Abstract:
A mask for protecting edge conductors of printed circuit boards from the spray coating which is sprayed on the board. The mask is molded from a soft silicone-based-elastomer material in a configuration which presents a sharp sealing edge and a large interior angle adjacent the seal which effectively limits migration due to capillary action.
Abstract:
Spray coating, particularly flat spray coating of circuit boards. Applicant's method of conformal coating, eliminates "railroading" at the edges of the flat spray web and assures precise control of the amount of coating material placed on the circuit board surface.The method includes longitudinally advancing a pressurized coating over a surface to be coated, while simultaneously feeding the coating in a flat spray pattern, and triggering feeding "ON/OFF" so as to proportion the amount of coating being fed onto the surface and to reduce "fishtail" at the edges of the flat spray pattern.
Abstract:
A method for moistureproof coating of an electrical product, which comprises applying an organic solution of a polyfluoroalkyl group-containing polymer dissolved in a non-combustible low boiling point organic solvent, to a surface of an electrical product, and drying it by evaporating the low boiling point organic solvent, to form a coating layer of the polyfluoroalkyl group-containing polymer on the surface of the electrical product, wherein said polyfluoroalkyl group-containing polymer is a copolymer of a polymerizable compound having a polyfluoroalkyl group with other polymerizable compound, and the copolymer has a glass transition temperature of not higher than 60.degree. C.
Abstract:
Ultraviolet curable polymerizable coating system having a built-in secondary curing mechanism is disclosed. The polymerizable coating system is a one component system comprising at least one urethane-acrylate or methacrylate, an allyl-group containing acrylate or methacrylate monomer, a non-allylic acrylate or methacrylate diluent, a polymerization initiator of the photoinitiator type, and a metal drier. The coating system is UV curable, and also possesses an additional cure mechanism.
Abstract:
Ultraviolet curable polymerizable coating system having one or more built-in secondary curing mechanisms is disclosed. The polymerizable coating system is a two component system comprising (1) a first component comprising at least one urethane-acrylate or methacrylate, and a mono or polyfunctional acrylate or methacrylate diluent and a polymerization initiator of the photo-initiator type, and (2) a second component comprising a polyisocyanate. The coating system is uv curable, and also possess at least one additional cure mechanism.
Abstract:
This invention describes a method of masking a workpiece to prevent the adhesion of a deposited tightly adhering conformal coating formed from the condensation of a vaporous diradical such as paraxylylene on selected portions of the workpiece. Specifically the process of the invention requires the covering of the areas of the workpiece, to which adhesion is not desired, with a non-polymerizing hydrocarbon and placing the covered area in close contact with an open cellular material containing a predominance of interconnecting cells which provides a large surface area for condensation of the unwanted condensate of the diradical, exposing the workpiece to the vaporous diradical, removing the workpiece from the open cellular material and immersing the workpiece in a solvent for swelling and dissolving the hydrocarbon covering.