Abstract: Apparatus for sequentially coating opposite major surfaces of a workpiece such as a printed circuit board and wherein the amount of manual handling is significantly reduced. Boards are arranged end-to-end preferably in closely spaced fashion upon a conveyor having an adjustable drive. First and second spray assemblies provide a low pressure spray having a substantially oval-shaped spray pattern and are arranged upon guide tracks to move in a reciprocating fashion in a direction transverse to the direction of movement of the conveyor for coating opposing surfaces of the workpiece. The speed of movement of the spray heads and the extreme ends of the range of movement are adjustable by controlling the operation of a drive motor to create a substantially Z-shaped spray pattern on the workpiece with the size of the Z-shaped pattern being a function of the conveyor speed spray head assembly, drive speed and range of movement of each spray head assembly.

Abstract: A method and apparatus for painting highway stripes and other patterns on a road surface includes the steps of heating the road surface to be painted or treated with a protective coating to a temperature typically in the range of 150.degree. F. to 165.degree. F. Paint is applied in spray form, the resin and hardener ingredients being mixed preparatory to spraying by a spray head. The paint mixture is sprayed onto the heated road surface as soon after the heat treatment as is practical. The paint spray may be heated as it passes through the nozzle. Granulated glass beads may be dropped onto the paint coating to enhance absorption of heat energy by the paint.

Abstract: Apparatus for coating a workpiece such as a printed circuit board. Boards are arranged in closely spaced fashion upon a conveyor having an adjustable drive. A spray assembly for providing a low pressure spray having a substantially oval-shaped spray pattern is arranged upon guide tracks and moves in a reciprocating fashion in a direction transverse to the direction of movement of the conveyor. The speed of movement of the spray head and the extreme ends of the range of movement are adjustable by controlling the operation of a drive motor to create a substantially Z-shaped spray pattern on the workpiece with the size of the Z-shaped pattern being a function of the conveyor speed spray head assembly, drive speed and range of movement of the spray head assembly.

Abstract: A molten metallic composition containing an undesirable concentration of a metallic element is heated in a vessel whose depth is greater than its width. The vessel is heated to have a temperature gradient such that the upper region of the vessel is at a greater temperature than the lower region(s). When the metallic element to be removed from the molten composition reaches a desired saturation level in the liquid metallic composition, the temperature gradient is reversed causing the formation of an intermetallic compound containing the metallic element. The intermetallic compound precipitates out as a solid material thereby facilitating its removal. The intermetallic content at the lower regions of the vessel are also controlled so that their composition contains a significantly reduced amount of the metallic element which has been precipitated out of the upper region.

Abstract: Method for pretreatment of the metallic surfaces such as conductive patterns on printed wiring boards to protect against oxidation and/or other contamination. Boards are passed through successive stations to perform the following operations at least upon the metallic surfaces of the boards: remove oily substances; microetch the conductive surfaces; form a protective monolayer with a solution compatible with soldering materials; remove excess protective coating by rinsing; air dry and infrared dry the protective coating; uniformly supply a preflux solution and dry the boards including clearing the preflux solution from any holes or openings within the boards; cool the boards to ambient temperature. Each step in which a solution or liquid is applied, is preferably followed by a rinse operation. The application and rinse operations are preferably separated from one another by a buffer zone.

Abstract: A preflux composition suitable for use as a preflux for protecting the solderability of copper during a heating cycle comprising rosin, antioxidant, and a solvent system comprised of glycol ether and terpene, process for protecting the solderability of copper which is to be subjected to a heating cycle prior to soldering comprising using said preflux composition, and articles comprising printed circuits or wiring boards which have copper areas coated with said preflux composition.

Abstract: An open-weave conveyor moves a printed wiring board through a region of radiant energy. The conveyor has a plurality of supporting projections extending from the major surface of the conveyor to minimize engagement between the conveyor and the board, providing at least three projections supporting each board above the open-weave conveyor to eliminate a shadow effect caused by radiation blocked by conveyor strands. Guides move the conveyor along an arcuate path away from the printed wiring board in the radiation region, assuring irradiation of the entire printed wiring board surface. This technique is advantageous for simultaneously irradiating both sides of a board during a dry film solder masking technique. The solder mask is radiated to promote cross-linking of the film polymer. To reduce thermal shock and abrupt temperature rise in the workpiece, the ultraviolet source includes a water envelope to absorb infrared radiation.

Abstract: A preflux composition suitable for use as a preflux for protecting the solderability of copper during a heating cycle comprising rosin, antioxidant, and a solvent system comprised of glycol ether and terpene and further including a dibasic acid, process for protecting the solderability of copper which is to be subjected to a heating cycle prior to soldering comprising using said preflux composition, and articles comprising printed circuits or wiring boards which have copper areas coated with said preflux composition.

Abstract: An open-weave conveyor moves a printed wiring board through a region of radiant energy. The conveyor has a plurality of supporting projections extending from the major surface of the conveyor to minimize engagement between the conveyor and the board, providing at least three projections supporting each board above the open-weave conveyor to eliminate a shadow effect caused by radiation blocked by conveyor strands. Guides move the conveyor along an arcuate path away from the printed wiring board in the radiation region, assuring irradiation of the entire printed wiring board surface. This technique is advantageous for simultaneously irradiating both sides of a board during a dry film solder masking technique. The solder mask is radiated to promote cross-linking of the film polymer. To reduce thermal shock and abrupt temperature rise in the workpiece, the ultraviolet source includes a water envelope to absorb infrared radiation.