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The EcowavePlus is a high performance wavesoldering system designed by Electrovert to optimise the no‐clean soldering process and to be environmentally friendly. The ‘green’ machine is configured to take advantage of the new volatile organic compound (VOC) free flux chemistries and the latest flux application techniques. Patented forced convection preheating is employed to ensure complete drying of water based fluxes. The coN2tour selective inerting system for the solder waves provides all the process benefits of inert soldering at an extremely low nitrogen consumption rate. All exhaust emissions in the machine are captured and treated before being released into the environment.

Augat/Isotronics now offer injection moulded, glass‐to‐metal sealed hybrid circuit packages providing many advantages over conventional machined components.

Drive east from Frankfurt, upstream along the valley of the River Main, and in 25 kilometres or so you will reach Hanau, where once the brothers Grimm lived and collected the folklore which we now know as the famous Tales. Here too, in 1856, Wilhelm Carl Heraeus, a chemist and pharmacist, proprietor of the pharmacy which had carried the family name for many generations, succeeded in producing temperatures approaching 2000°C from an oxy‐hydrogen flame, temperatures sufficiently high to achieve the melting point of platinum and to allow him to melt substantial quantities of this metal for the first time. Hanau was then a centre for the jewellery manufacturing industry (and remains so today) so the smelting of platinum and other precious metals had an immediate commercial relevance.

TEN years ago, Imperial Metal Industries (Kynoch) Ltd. confined their interest in the so‐called new metals (i.e. those not then available for commercial use) to titanium. This metal by itself provided I.M.I. metallurgists and engineers with more than enough headaches, as they learned to cope with its very high melting point, its habit of absorbing deleterious gases and the modifications it imposed on normal metal‐working processes.

The increasing complexity of hybrid circuits has led to a need for a reliable multilayer system. As well as reliability, the manufacturer will, of course, also attach considerable importance to material and production costs. Until now, thick film multilayer applications have been limited by the inability of existing technology to reduce their susceptibility to galvanic effects occurring between individual conductive layers during fabrication. Now, however, this company has developed a multilayer dielectric which prevents metal migration. The system is supported by conductor and resistor systems.

This paper describes the fabrication of integral screen printed platinum resistance elements. A detailed description is given of the techniques of element manufacture and performance. The paper is finally illustrated by an example of sensor integration into a temperature critical subsystem. This example serves to demonstrate the potential manufacturing economies achieved by this approach.

Manufacturers of multilayer copper thick‐film circuitry face the challenge of firing parts in an inert nitrogen atmosphere to prevent the copper from oxidising. Nitrogen, while protecting the copper from oxidation, offers no efficient mechanism for removing the carbon‐based vehicles used in the copper thick‐film paste. Because of this, carbon residues or soot often deposit on the parts during the firing process. In an attempt to improve the nitrogen furnace atmosphere's ability to remove the vehicles, several gases or gas blends were added to a nitrogen‐based furnace atmosphere. Thick‐film copper conductors and dielectric test pieces were then processed using the various gas blends. The physical properties of adhesion, aged adhesion, solderability, and conductivity of the copper conductor test pieces were studied along with the dielectric properties of dissipation factor, insulation resistance, and dielectric constant. Some of the gases tested included H2, H2O, CO, CO2, and a variety of other gas combinations. Test results demonstrated the atmosphere's ability to effect changes in the physical properties of the parts being processed. A proprietary gas blend was developed which proved effective in removing carbon residues while maintaining the desirable physical properties of the thick films. This work demonstrates the ability of certain gas additives to improve the performance of conventional nitrogen atmospheres when firing copper thick‐film circuitry. With the proper selection of the gas additive, atmosphere flows can be reduced, carbon residues eliminated, and the physical properties of the copper conductors and dielectrics maintained or improved.

Reducing Level of Alcohol in Inks ‐ A medium‐sized US ink manufacturer recently needed to reduce the level of alcohol in its bases for water‐based inks. Ciba Geigy Pigments Division's Inks Technical Centre developed an improved formulation, containing half the alcohol of the previous one and 40 per cent more pigment to allow the ink producer to meet VOC limits and increase production efficiency, at no additional cost.

As electronic devices have become more complex and interconnection density has increased, electronics manufacturers are facing new challenges to solder SMD packages with pitches down to 0.3 mm or less. To achieve positive results, all parameters throughout the soldering process have to be optimised. The first step on the SMT line is the application of solder paste. Any faults at this stage (material, equipment or process related) will be carried through the entire production line. Solder paste is one of the most important factors in the whole chain. It is important to understand the influence of the metal powders, activators, solvents and additives on soldering of ultra‐fine pitch SMDs. Special attention must be paid to the powder (fine pitch devices demand a fine grain in the solder paste). The reliability of the soldered joints is mainly dependent (apart from on the solder paste) on the solder quantities applied to the component pads, the tolerance regarding the shape and size of stencils + PCBs + SMDs, the accuracy of mounting and printing, and on the reflow profile. It is important to design the stencil apertures with sufficient surface area to provide enough surface tension (between the paste and the component pad) to pull the solder paste out of the stencil, while keeping the component pad small enough to match the lead of the component. As the wetting of fine pitch components is especially critical, it is necessary to pay more attention to the design of the reflow profile. It is recommended to solder ultra‐fine pitch components under nitrogen, as this enlarges the process window considerably.