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Anti-Corrosion Methods and Materials, vol. 51 no. 4
Type: Research Article
ISSN: 0003-5599

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Peter Meeh

This paper describes a state‐of‐the‐art process for immersion tin plating of PCBs which is used to preserve solderability prior to assembly. The process sequence is…

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This paper describes a state‐of‐the‐art process for immersion tin plating of PCBs which is used to preserve solderability prior to assembly. The process sequence is described and preventive measures for handling the final surface finish is documented. A solderability test method and basic requirements for fluxes and soldering parameters are also described. Quantitative results on the formation of intermetallic tin‐copper phases are shown and their influence on the formation of tin whiskers explained. A problem in production is the precise measurement of the tin thickness, therefore different measuring methods are also detailed. Finally, the mechanism of tin deposition and the formation of tetravalent tin and the relationship with bath age and deposit quality are discussed.

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Circuit World, vol. 31 no. 1
Type: Research Article
ISSN: 0305-6120

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G. Becker

This issue of the journal features the first part of a two‐part serieswhich comprises Chapter 15 from Volume 1 of a recently published book ‘AComprehensive Guide to the

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This issue of the journal features the first part of a two‐part series which comprises Chapter 15 from Volume 1 of a recently published book ‘A Comprehensive Guide to the Manufacture of Printed Board Assemblies’*edited by W. MacLeod Ross. Volume 1, containing 800 pages, and Volume 2, scheduled to be published in the Spring of 1997 and estimated to contain around 900 pages, will, as far as the publishers are aware, be the most comprehensive book ever published on the subject of printed boards and printed board assemblies.

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Soldering & Surface Mount Technology, vol. 8 no. 3
Type: Research Article
ISSN: 0954-0911

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B.N. Ellis

This paper outlines the composition of water soluble fluxes for the electronics industry and their methods of use when wave soldering and reflowing tinned coatings and…

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This paper outlines the composition of water soluble fluxes for the electronics industry and their methods of use when wave soldering and reflowing tinned coatings and solder pastes. Process optimisation is facilitated by the Taguchi method. Three types of cleaning machinery are evoked, with varying results. It is shown that the energy/time relationship is important to ensure adequate cleaning quality. A number of fallacious arguments are debunked. Methods of water purification and the problems of effluent treatment for all sizes of installation are addressed. Doubt is expressed as to the viability of closed‐circuit water recycling except for the largest installations or where exceptional conditions prevail. It is shown that water soluble fluxes and their subsequent aqueous removal are unlikely to make any significant contribution to the Greenhouse Effect. The overall cost of their use is substantially similar to that of rosin fluxes with CFC‐113 azeotropes at 1986 prices. Cleanliness control under production and laboratory conditions is discussed with reference to both ionic contamination testing, including its use for SMDs, and SIR analysis, especially at low voltages, including non‐destructive production SIR testing. Reliability of the assembled circuits is shown to be at least as good as that with more traditional soldering and cleaning methods, frequently better, and this is the case even for military and aerospace applications. The paper concludes that, now that quality water soluble solder pastes are available, this method is most likely to become the workhorse for the majority of electronics applications.

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Soldering & Surface Mount Technology, vol. 3 no. 2
Type: Research Article
ISSN: 0954-0911

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Circuit Technology, now in its fourth year, is still an event concentrating exclusively on PCB technology, production equipment and processes. Nevertheless, the organisers…

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Circuit Technology, now in its fourth year, is still an event concentrating exclusively on PCB technology, production equipment and processes. Nevertheless, the organisers believe that Circuit Technology '86 will derive great benefit from participation in the UK's largest electronics gathering, The British Electronics Week.

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Circuit World, vol. 12 no. 3
Type: Research Article
ISSN: 0305-6120

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G.A. Quadir, Anvar Mydin and K.N. Seetharamu

A finite element method is applied to evaluate the performance of microchannel heat exchangers that are used in electronic packaging. The present approach is validated…

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A finite element method is applied to evaluate the performance of microchannel heat exchangers that are used in electronic packaging. The present approach is validated against the CFD data available in the literature. A comparison of the predicted results with other available results obtained from different concepts shows that the present method is able to predict the surface temperature, the fluid temperature and thus the total thermal resistance of the microchannel heat sink satisfactorily. The present methodology has an added advantage in that non‐uniform surface heat flux distribution over the package base can also be analysed easily. The method used in the present analysis is an alternative to massive CFD calculations.

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International Journal of Numerical Methods for Heat & Fluid Flow, vol. 11 no. 1
Type: Research Article
ISSN: 0961-5539

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C. Hunt

The development and characterisation of a prototype solderability reference standard basedon a gold‐plated nickel sample has been described previously. This material has…

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The development and characterisation of a prototype solderability reference standard based on a gold‐plated nickel sample has been described previously. This material has now been tested in an intercomparison with several European laboratories. The results presented here show that a high degree of repeatability is achievable. These results substantiate earlier ones and confirm this material's applicability as a solderability reference material.

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Soldering & Surface Mount Technology, vol. 8 no. 2
Type: Research Article
ISSN: 0954-0911

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W. Lambert

Factors relating to the cleaning of PCBs after soldering are examined, whereby the need to remove flux residues is justified and the choice of suitable cleaning agents…

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Factors relating to the cleaning of PCBs after soldering are examined, whereby the need to remove flux residues is justified and the choice of suitable cleaning agents analysed. After a description of recommended equipment design involving a 2‐stage system, methods of automating this are outlined.

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Circuit World, vol. 9 no. 3
Type: Research Article
ISSN: 0305-6120

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Since its advent in 1983, Circuit Technology has gone from strength to strength, as indicated by visitor attendance which increased from 3000 in 1983 to over 6000 in 1984…

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Since its advent in 1983, Circuit Technology has gone from strength to strength, as indicated by visitor attendance which increased from 3000 in 1983 to over 6000 in 1984. Predictions are that, with the larger venue at Olympia's National Hall, previous attendance figures will be exceeded many times at Circuit Technology '85.

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Circuit World, vol. 11 no. 3
Type: Research Article
ISSN: 0305-6120

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An OBS/Karcher high pressure solvent spray jet washing system installed at Joseph Mason Paints at Derby has greatly improved the speed and ease of cleaning of paint mixing…

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An OBS/Karcher high pressure solvent spray jet washing system installed at Joseph Mason Paints at Derby has greatly improved the speed and ease of cleaning of paint mixing vessels. Supplied by OBS Machines of Milton Keynes the new system, which cleans a vessel in just a three minute wash cycle, is currently handling over 70 mixing vessels a day.

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Pigment & Resin Technology, vol. 18 no. 2
Type: Research Article
ISSN: 0369-9420

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