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This paper aims to analyse the tack stability measurement readings of thermochromic offset inks. For this purpose, three reversible leuco-dye formed thermochromic inks were used to evaluate their tack. The used inks differ in their activation temperature, colour, drying mechanism, viscosity and chemical content. Thermochromic offset inks differ from conventional inks in formulation and size of colourants due to the presence of the microcapsules.

Printing inks in offset lithography must have sufficient tack so they can be transported from a reservoir onto the substrate. The ink transfer takes place through the ink splitting by inking rollers, printing plate and blanket transport. An IGT Tackoscope device was used to produce the dynamic readings of ink tack as a function of distribution and splitting time. The data can be used for prediction of the ink press stability under controlled settings, such as temperature.

This research explains the temperature and velocity influence on the tack stability measurement readings of thermochromic inks. It also gives an insight of the chemical compounds that dictate the tack measuring reading results.

Development of new printing inks, such as thermochromic printing inks, may affect the printing of different products. The research was conducted due to a lack of available data for the tack of thermochromic inks.

Compares Coldset and Heatset lithographic processes and shows why Heatset dominates the market for the production of supplement inserts and promotional articles for the news industry. Discusses the progress that has been made in a collaborative project to improve the performance of the Coldset process. States that further progress is required to make Coldset truly competitive with Heatset.

Increasingly stringent quality and cost requirements have brought about a revival in the use of stainless steel cloth as a production tool for screen printing. Process factors are examined to support the choice of stainless steel for its stability and potential for high registrational accuracy printing. Screen making is of vital importance to the end result, and the achievement and maintenance of uniform tension are as critical for stainless steel as for other screen media. Full specification of printing screen requirements is essential, as is incoming goods inspection of cloth and finished screens. The entire weaving process contributes to the overall quality of stainless steel cloth and, although post‐production correction procedures are available, they are undesirable and can be avoided by a carefully controlled weaving process.

Instrumentation to be shown will include: The Brookfield Helipath stand may be used with a suitable Brookfield viscometer fitted with a T‐bar spindle, the Helipath stand permits viscosity measurement of materials i.e. pastes, putty, creams, gelating, wax, resins and inks. The Stand incorporates a synchronous motor which automatically lowers or raises the viscometer enabling its rotating shearing element to describe a helical path through the sample.

THERE have been official links for the past twelve years between the Institute of Incorporated Work Study Technologists and Time and Motion Study. Many of its members have been valued contributors to our pages and the Institute has had editorial space for its news.

The rheology of solder paste significantly affects the qualities of stencil printing, tack and slump performance. This paper describes a series of tests performed on solder paste to investigate and determine the rheological properties of a group of solder pastes and fluxes, and the correlation of those properties with paste performance prior to reflow. Data indicate that: the incidence of print defects are proportional to the material’s compliant qualities (J1 and J2) and are inversely proportional to the elastic properties (G¢/G¢¢ and recovery) and meta‐rigidity (yield stress); slump resistance is proportional to elastic properties (recovery), solid characteristics (stress [G¢ = G¢¢]), and rigidity (|G*|); and that high elastic properties (recovery), low compliance (J1 and J2), and low solid characteristics (stress [G¢ = G¢¢]) are required in order to achieve high tack value. Good correlation between fluxes and solder pastes were observed for yield stress and recovery only, suggesting that those two properties are primarily dictated by fluxes.

In the “dry” state, pigment particles are held together by attraction forces of various physical chemical natures including the van der Waals force and the “liquid bridge” force. These attraction forces must be overcome in order to disperse pigment particles into liquid media. Dispersion machinery is designed to generate energy required to overcome, to various extents, such attraction forces. On the other hand, the efficiency of dispersion operation is significantly dependent upon the effectiveness of the transfer of energy from the dispersion tools/dispersion charges to the oversized pigment particles, as a result of the presence of the adhesion and cohesion within the dispersion system. This paper explores the nature and the significance of various forces between pigment particles and of the adhesion and cohesion phenomena associated with pigment dispersion, from a practical point of view. Principles relevant to improving the efficiency of pigment dispersion via minimisation of the adhesion between pigment particles and via maximisation of the adhesion and cohesion within the dispersion system are also discussed.

To drive along winding roads from the south‐east shores of Lake Constance not far from where the mighty Rhine enters the lake, passing small rural settlements and isolated chalets as the road weaves its way upwards through patches of woodland, with the landscape clad in the first snow of the season, may savour more of arrival for an early Winter sports holiday than for a company visit. At an altitude of some 700 metres, however, on the outskirts of the village of Wolfhalden, which has a population of about 1,700, Circuit World's destination during late November was the wire weaving plant of G. Bopp & Co. AG, whose head office is located in Zürich.

The Electroplating Products and Equipment Business Area of Degussa AG, Frankfurt am Main, Federal Republic of Germany, has begun to supply a new selective electroplating plant. Under a co‐operation agreement with the Telmec company of Milan, Italy, this business area of Degussa, which is based in Schwäbisch Gmüd, Germany, has begun to market the Telmec SL 6 ‘Tab Plater’ throughout the world, with the exception of Italy and France. The equipment was developed specially for manufacturers of printed circuit boards, and is used for the continuous electroplating of strip contacts on these boards.

IT is difficult to imagine the world of Work Study without the urbane ubiquity of Russell Currie, whose death on 28 August we deeply regret to record. Although he had been officially in retirement for a year or two his presence was immanent in any important gathering of those who had so long looked to him for the leadership that was always forthcoming. We can fittingly borrow an epigram he coined at the London Congress in 1963 as apt at this time. ‘The sun shone to greet your arrival; the skies weep for your departure.’