Abstract: A metal casting process for producing melt-out metal cores and the like made of metal alloys with low melting temperatures achieves a casting with uniform density, high quality finish and a fine grain structure. The process and apparatus do not require the pre-pressurization of a charging cylinder and permit closed dies to be used. The apparatus comprises a molten metal alloy tank, a cylinder in the tank having at its base a connection to a passageway leading through the tank to a die located outside the tank. A valve is provided in the passageway, located in the tank having a first position where the passageway to the die is open and a second position where the passageway to the die is closed. In the second position, a valve port provides a connection from the cylinder to the molten metal alloy in the tank.

Abstract: An induction heating system for melting metal cores contained within articles or components made of plastic uses induction heating and redirects flux lines for efficient melting. The system includes a high permeability magnetic core, an induction heating coil about at least a portion of the magnetic core to produce flux circulation in a magnetic circuit formed by the magnetic core, and two magnetic nozzles attached to the magnetic core with a gap therebetween for insertion of a specific shape of plastic article, the magnetic nozzles shaped to direct and position a desired pattern of flux lines to heat and melt the metal core of the plastic article.

Abstract: A tunnel for fluxless soldering, is a straight linear tunnel which contains vibrating means to vibrate a solder wave and a non-explosive gas atmosphere. The gas atmosphere includes a small portion of hydrogen or other gaseous reducing agent, sufficient to achieve a fluxing action. A process for soldering an element comprises the steps of conveying the element through a tunnel containing a non-explosive gas atmosphere substantially excluding oxygen, heating the element in the tunnel, soldering the element, and retaining the element in the gas atmosphere of the tunnel until solder on the element has solidified.

Abstract: A wave soldering apparatus and process occurs in an atmosphere which substantially excludes oxygen. By providing a pressurized effect on an element to be soldered while passing through a solder wave, fluxless soldering is accomplished avoiding the necessity to remove flux residues. The element is preheated in a shield gas atmosphere substantially excluding oxygen, moved in a predetermined path so that at least a portion of the element passes through the solder wave which is oscillated while the element is in the solder wave and maintained in the shield gas until solder on the element has solidified.

Abstract: A method and apparatus for cleaning workpieces, particularly printed circuit boards upon which electrical components have been soldered, is capable of using a potentially flammable or explosive liquid cleaning solvent. In one embodiment, there are two immersion wash stages between which is a spray wash stage. The spray wash stage is formed as a closed chamber which is sealed when the immersion wash stages by liquid seals. To reduce the danger of fire or explosion in the spray wash stage an inert gas such as Nitrogen is introduced into the closed chamber. In another embodiment the spray nozzles are immersed in liquid solvent in a combined immersion/spray wash stage. This reduces atomization of the flammable solvent further reducing the danger of fire or explosion.

Abstract: A metal casting process for producing melt-out metal cores and the like made of metal alloys with low melting temperatures achieves a casting with uniform density, high quality finish and a fine grain structure. The process and apparatus do not require the pre-pressurization of a charging cylinder and permit closed dies to be used. The apparatus comprises a molten metal alloy tank, a cylinder in the tank having at its base a connection to a passageway leading through the tank to a die located outside the tank. A valve is provided in the passageway, located in the tank having a first position where the passageway to the die is open and a second position where the passageway to the die is closed. In the second position, a valve port provides a connection from the cylinder to the molten metal alloy in the tank.

Abstract: An improved valve mechanism for casting metal alloys with low melting temperatures provides two valves in a single assembly inside an alloy tank. The valves being in the tank reduces the formation of oxides which can occur in air and tends to reduce leaks. The apparatus comprises a tank adapted to contain molten metal alloys, a cylinder in the tank having at its base a connection to an injection passageway which leads through the tank to a die located outside the tank. A piston reciprocates in the tank which allows molten metal alloy to be drawn into the cylinder and forced through the passageway to the die. A control system for the piston controls accurately the speed of the piston in the cylinder when the molten metal alloy is fed to the die.

Abstract: A flux density control system controls the density of flux or other liquid by measuring the density and adding a thinner solvent or other liquid with a lower density than the flux. The apparatus includes a tank having an overflow adapted to maintain a set level of liquid in the tank, a liquid container positioned to receive liquid from the overflow in the tank, and a liquid pump adapted to pump liquid from the liquid container to the tank. A thinner container is provided with a thinner pump adapted to pump thinner from the thinner container to the tank. A density probe is positioned in the tank with a controller to turn off the liquid pump when the density of liquid in the tank rises above a predetermined set point, and turn on the thinner pump. The controller also turns off the thinner pump and turns on the liquid pump when the density of liquid in the tank drops below the predetermined set point.

Abstract: Printed circuit boards, assemblies and the like are heated uniformly from edge to edge or to a desired lateral temperature profile while being conveyed through a heating area. The conveying systems reliably conveys circuit boards and the like through the heating area without dropping them. A rail heater is provided to heat rails supporting conveyors having pins to hold circuit boards and the like. A control for the rail heaters controls the temperature of the rails so the circuit boards are positively supported on the conveyors and have a uniform temperature profile or desired temperature profile from edge to edge.

Abstract: A metal casting process for producing melt-out metal cores and the like made of metal alloys with low melting temperatures achieves a casting with uniform density, high quality finish and a fine grain structure. The process and apparatus do not require the pre-pressurization of a charging cylinder and permit closed dies to be used. The apparatus comprises a molten metal alloy tank, a cylinder in the tank having at its base a connection to a passageway leading through the tank to a die located outside the tank. A valve is provided in the passageway, located in the tank having a first position where the passageway to the die is open and a second position where the passageway to the die is closed. In the second position, a valve port provides a connection from the cylinder to the molten metal alloy in the tank.

Abstract: A process for induction heating of melt-out metal cores contained within articles or components made of plastic. The process uses induction heating and redirects flux lines for efficient melting. A high permeability magnetic core is heated by an induction heating coil about at least a portion of the magnetic core to produce flux circulation in a magnetic circuit formed by the magnetic core. Two magnetic nozzles are attached to the magnetic core with a gap therebetween for insertion of a specific shape of plastic article, the magnetic nozzles being shaped to direct and position a desired pattern of flux lines to heat and melt the metal core of the plastic article.

Abstract: A cooling and exhaust unit for an IR reflow soldering machine is arranged to be mounted on the soldering machine after the last heating zone. The unit has fans which direct cold air downwardly on to the conveyor and this cooling air divides into two streams, one moving with the conveyor and one counter to the movement of the conveyor. An exhaust inlet is provided near the front and the rear of the machine, the exhaust inlets being connected through an exhaust chamber to an exhaust outlet. To minimize the amount of hot process air sucked out of the soldering machine into the nearer exhaust inlet an additional cold air inlet is provided, this being located intermediate the rear end of the unit (i.e., the end abutting the soldering machine) and the nearer exhaust inlet.

Abstract: Automatic wave solder apparatus having a fluxer section, preheater section and wave soldering section through which circuit boards are passed by a conveyor. All of the major process parameters are monitored by a microprocessor. One specific parameter controlled is the temperature of the boards exiting from the preheater system. Preheating is carried out by two axially spaced banks of heaters, the upstream one supplying the major quantity of heat and the downstream one supplying sufficient heat to boost the temperature to the desired value. A pyrometer located in the zone between the two banks of heaters measures the heat radiated from the boards and this information is converted by the microprocessor to an appropriate instruction to the second bank of heaters. The soldering section has a solder pot assembly particularly adapted to the automatic nature of the apparatus. The pot can be jacked to the correct height according to the length of leads projecting from the boards under control of the microprocessor.

Abstract: Apparatus for treating electronic components comprises a frame, a lower track mounted on the frame for supporting the components, and an upper track mounted on the frame in a normal operating position above and in spaced-apart parallel relationship to the lower track. The lower and upper tracks define therebetween a path along which the components can pass for treatment. Pusher fingers are provided each having a portion which extends substantially horizontally in such a manner as to be insertable between the tracks and engageable with individual ones of the components. A drive is mounted on the frame for propelling the fingers. The components are held captive between the lower and upper tracks, and the fingers engage individual ones of the components and propel them along the path.

Abstract: Wave soldering apparatus particularly adapted for soldering printed circuit boards which have closely packed chip components adhesively mounted on one side of the boards is described. A novel nozzle assembly is dimensioned to be mounted to the solder supply conduit of a conventional wave soldering reservoir. The nozzle assembly comprises a first nozzle which delivers a turbulent jet to the undersides of the printed circuit boards as they are conveyed over the nozzle assembly, and a second nozzle which delivers a smooth laminar wave through which the undersides of the printed circuit boards immediately subsequently pass. The turbulent jet forces solder into the restricted spaces at which chip component contact pads are located and the smooth wave completes this soldering action by building of additional solder in a manner which discourages the formation of solder "icicles" and bridging.

Abstract: A fixture for holding flexible printed circuit board substrates formed by front and rear screens each of a wire mesh material which are hingedly connected together and held at their top by a fastening arrangement such that the flexible substrate may be held therebetween, the material of the screen (e.g., titanium) being non-wettable by and capable of withstanding the temperature of molten solder.

Abstract: A shock-resisting suspended cable trough assembly includes open channel supporting members extending transversely beneath the trough. At their ends, the channel members are formed with box channel end portions and the upper and lower webs of those box channel end portions are formed with aligned and open-ended slots to receive the threaded lower ends of generally vertical legs of respective hangers. At its upper end, each hanger is formed with a generally horizontal arm which is received in an opening in a mounting bracket depending from an overhead support so that the arm is generally parallel to the longitudinal direction of the trough. The arm of each hanger forms an integral extension of one limb of a generally horizontal U-shaped intermediate portion while the other limb of such U-shaped portion is integrally formed with the upper end of the leg of the hanger through an elbow.