It often becomes necessary to analyse a grease for a variety of reasons:
Laser soldering, as a viable technique for surface mounting assemblies, is reviewed. The criteria for selection of a CO2 or a Nd:YAG laser are discussed. New data are…
Laser soldering, as a viable technique for surface mounting assemblies, is reviewed. The criteria for selection of a CO2 or a Nd:YAG laser are discussed. New data are given that quantify the beneficial effects of laser soldering on the solder fillet microstructure, and how this relates to in‐service performance.
A recent export to India by The General Electric Co. Ltd., of Magnet House, Kingsway, London, W.C.2., was an infra‐red plant to speed the finishing of 40 gallon oil drums…
A recent export to India by The General Electric Co. Ltd., of Magnet House, Kingsway, London, W.C.2., was an infra‐red plant to speed the finishing of 40 gallon oil drums for installation at the Calcutta Works of the Indian Galvanising Co. (1926) Ltd. The plant is in two sections ; one dries the newly‐made drums after they have had an underwater pressure test, the other stoves the finish, and is capable of coping with an output of some 80 drums per hour.
In mass‐production of PCBs, visual inspection of soldered joints has probably been the last major operation still performed manually. A system has been designed to ensure that the accept/reject threshold is firmly held at a pre‐set level, to detect defects on or under the surface, to identify these defects by type, severity and precise location and to carry out the inspection at high speeds with full automation. The system's operation is based on a laser firing a pulse of radiation onto a solder joint, an infra‐red detector monitoring joint temperature changes, a programmable XY table, a computer storing the thermal signatures of acceptable and rejectable joints and a device for programming, displaying and recording all necessary data. Enhanced reliability and cost savings are possible with this automated process of inspection.
This issue of the journal features the final 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 board assemblies.