Sitall Glass-Ceramic Treatment Technology for the Case of Etching and Cleaning of a Ring Laser Monolithic Crystal

The paper uses production of the main part of a ring laser, that is a monolithic sitall crystal, as an example to describe the main stages of manufacturing and chemical processing of the SO-115M lithium aluminosilicate sitall glass-ceramic material. We analysed composition optimisation and glass-ceramic production methods and investigated the effects of various components (such as glass formers, modifiers, and clarifiers) on the optical performance of the finished article. We describe the sequence of main monolithic crystal processing operations: etching and cleaning, which includes degreasing, ultrasonic treatment, rinsing and drying. We tested an original etchant formulation and present an etching rate calculation for it. We selected a solution for ultrasonic cleaning of the article and assessed the resulting surface finish quality

Artefacts between disciplines. Response to responses

As is often the way, a ‘finished’ article disguises aspects of its own production and gives an overly orderly account of theoretical and methodological moves which were not especially planned. In responding to our commentators and in coming clean about our own working methods we have some confessions to make. In making these admissions we continue what has by now become a conversation about matters of interdisciplinarity and about our approach to the axe and the toothbrush.

Review Lecture: The control of industrial processes

All sections of Industry are concerned to improve the efficiency of their production methods and, in general, this can only be achieved either by the design of new plant employing more efficient processes or by better control of existing plant. Almost all manufactured goods involve a very large number of processes and more often than not a large number of different components have to be assembled together in order to produce the finished article. The objective in any factory is to produce a specified quantity of goods for the lowest possible cost and if this is to be achieved it is evident that control must be exercised at a number of different levels in the factory. Not only must each machine be producing components in the most efficient manner but, when they have been produced, the different components must be brought together at the assembly line in the right proportions and at the right time for the assembly to continue both smoothly and efficiently. Most, if not all, factories produce closely specified products from closely specified raw materials; the plant is designed, built and maintained to do just this and so it might be expected that there is no control problem. Unfortunately, however, there are very few factories which are required to produce exactly the same product day in day out for the whole of their useful lives. Even in the giant basic industries like Electricity and Oil we find that although in the Oil industry the products remain the same the relative quantities required differ from summer to winter, while in Electricity although there is only one product, which, by act of Parliament, has to be maintained within very close limits, the quantity required is continually changing and so power stations have to be switched in and out sometimes at short notice. In Industry, therefore, the first control problem is to estimate the quantities of the different products which have to be manufactured.

An Immersion Test for Rubber Compounds

The immersion procedure described here is much faster than the present A. S. T. M. method, and gives results of comparable accuracy. It requires less space and less solvent. The most serious objection to it is the occurrence of anisotropic swelling due to grain in the rubber. However, there is usually more grain in manufactured articles, such as hose, than in tensile sheets. Both methods are useful chiefly for the preliminary evaluation of compounds. The final test frequently is made on the finished article under special conditions. The sensitivity of this test to grain effects suggests that its use with a good swelling agent will be a useful tool for measuring the extent of such grain in various compounds.

Oil-Resisting Rubber

From the mechanical engineer's point of view, rubber has one serious drawback, and that is the behavior toward lubricating oil. By proper compounding and curing, rubber is being used under circumstances which involve contact with oils, but there is still room for improvement. When one considers that oil-resisting rubber is finding and could find still greater application in the engineering, especially the automobile, electrical, petroleum, gas, paint, printing, agricultural, and other industries, it is not astonishing that this problem is one of the most important of the rubber industry. Little work, however, has been published on this subject prior to the present year. The popular belief that glue protects rubber against oil has been shown to be incorrect, and will be dealt with later in the paper. Ishiguro (Rubber Chem. & Tech., 6, 278 (1933)) studied a large number of fillers, soaps, glue, starch, and accelerators, but in view of the fact that the author did not make a preliminary study of the effect of these substances upon cure, the reader of the paper is left with the impression that the results are due as much to the effect of the various substances upon the state of cure as to their intrinsic oil-resisting properties. It is true that a certain amount of correction was made in the case of accelerators. The paper must, however, be welcomed as the first systematic publication based on experimental work on this subject. Karsten (Kautschuk, 9, 73 (1933)) brings out a very important point in his paper to the effect that the best method of obtaining oil-resistance in rubber must depend upon the use to which the finished article will be put: for example, large proportions of reinforcing fillers and glue cannot be used when a flexible rubber is required, and so on.