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Machining operations on multilayer circuit boards play the two major roles of establishing the finished geometry of the board and leading to the interconnection of the various conductor layers and it is likely that for some considerable time carbide cutting tools will continue to be used in the machining process. Fundamental and detailed considerations of the parameters influencing machining are presented prior to analysing the two predominant areas of use. Mention is made of some advanced machining techniques, involving mechanical, chemical and laser methods.

A balance of commercial factors as well as appreciation of its position at the “crossroads” of the East has enabled Singapore Airlines to surmount the recession which has affected so many of the world's carriers. An advanced technology fleet is of prime importance with replacement taking precedence over certain considerations. This process can be said to have begun in earnest in 1967 when new Boeing 707 and 737 aircraft were ordered. Before that time, the airline could not afford such expensive acquisitions.

AN area of major development by the aerospace industry has been to obtain substantial weight savings in aircraft structures so that range and loading capacities are increased as well as economies made on fuel. These objectives are being achieved without any reduction in structural strength and flight integrity, by incorporating advanced composite products such as Du Pont's Kevlar and carbon based materials.

ALUMINIUM was first produced commercially almost 100 years ago and is still a long way from realising its potential. Its high ductility, strength and toughness, light weight and corrosion resistance properties are well‐known. Mixed with particles or fibres of other materials, such as alumina, aluminium is now becoming the basis of a whole range of new metal matrix composites (MMC's) providing an extreme high strength‐to‐weight ratio.

THAT THE NEWSPAPER industry has gone through a tremendous change has been obvious to all by the horrific scenes of violence shown on television over the past several months.

IN only a few years Garryson Ltd of Ibstock in Leicestershire has become the leading U.K. specialist in solid carbide round tools. Traditionally British users of these tools have had to turn to American, German or Swiss suppliers because no satisfactory home‐based manufacturer existed, but in 1985 Garryson decided to fill this gap in the market.

The expected return on major investment by Aerospace Forgings Ltd, in CAD/CAM and computer‐controlled die‐sinking machine tools has only been fully realized with a switch from high speed steel (HSS) to solid and inserted carbide cutting tools which have been supplied by Stellram of Melksham.

This paper aims to deal with the influence of cutting parameters on drill thrust force, delamination and surface roughness in the drilling of laminated jute/carbon hybrid composites.

The hybrid composites were fabricated with four layers of fabrics, which are arranged in different sequences using the hand-layup technique. Drilling experiments involved drilling of 6 mm diameter holes on the prepared composite plates using high-speed steel and solid carbide drill materials. Analysis of variance was used to find the influence, percentage contribution and significance of drilling parameters on drilling-induced damages. Scanning electron microscopy analysis was also conducted to understand the fracture behavior and surface morphology of the drilled holes.

The experimental study reveals that the most significant effect was the feed rate influenced the drill thrust force and the drill speed influenced both delamination factor and surface roughness of hybrid fiber-reinforced composites. From observations, the suggested combination for drilling jute/carbon hybrid composites is carbide drill, spindle speed of 1,750 rpm and feed of 0.03 mm/rev.

The new lightweight and low-cost hybrid composites were developed by hybridizing jute with carbon fabrics in the epoxy matrix with interplay arrangements. The influence of cutting speed and feed rate on delamination damage and surface roughness in the drilling of hybrid composites have been experimentally evaluated.

This study aims to clarify the influence mechanism of surface texture (arrays of circular/square and concave/convex) on the frictional properties of WC-TiC/Co cemented carbide under a water-miscible cutting fluid (JAEGER SW-105, 5 per cent) environment.

Four types of textured cemented carbide surfaces (arrays of circular/square and concave/convex that have different textured densities and sizes) were fabricated using laser surface technology. Pin-on-disc tests between an AISI 304 stainless steel ball and WC-TiC/Co cemented carbide samples were carried out for a variety of normal loads (1, 3 and 5 N) under a water-miscible cutting fluid environment. The effects of textured type, density and size on the friction coefficient were obtained.

Compared to a smooth surface, some textured samples successfully resulted in a reduced friction coefficient. The friction coefficient of textured WC-TiC/Co cemented carbide samples depended greatly on the textured type, density and size. Given the increase in textured density (ranging from 10 to 30 per cent), the friction coefficient of the test samples first decreased and then increased for all normal loads (1, 3 and 5 N), and the minimum friction coefficient was obtained at the textured density of 20 per cent. The concave textured surface showed obvious advantages in friction coefficient reduction regardless of textured density, size and normal load compared with the convex textured surface. Finally, the correlation between textured diameter/length and Hertzian contact width was studied for various normal loads and texture sizes. A 2.6 ratio of textured diameter/length to Hertzian contact width is recommended under for lubricated sliding contact with the water-miscible cutting fluid.

The main contribution of this work is in providing a design reference and obtaining an essential understanding on the effect of surface texture (arrays of circular/square and concave/convex) on the friction of WC-TiC/Co cemented carbide under a water-miscible cutting fluid environment.