1970, No. 5/6 127 Forty years of workshop technology B. L. ten Hom Introduetion In many kinds of industry workshop technology is a Every form of mechanical production involves a vital and basic activity. Yet it is not so easy to define large quantity of mainly geometrical information. This exactly what "workshop technology" implies, for there information originates in the conception and develop- are so many kinds of workshop using such a wide ment of a product. In the specification and detailing variety of techniques. of a design in the drawing office an enormous amount In the Netherlands, long a sea-faring nation, engi- of information is added, which is set down, in all its neering works and boiler-makers' shops first grew up multitudinous ramifications, in engineering drawings [1l. around the shipyards, and they probably represent the Behind the indications on the parts lists of these draw- oldest form of workshop technology in this country. ings there is a wealth of information packed in stan- It was a natural step for these shops and works, which dards sheets. originated around the ship's engine and its boiler, to The "workshop" in its various forms mentioned help to provide for the needs of the power and chemical above always contains the interface between the world industries. of the designer, dealing in abstract ideas, and the world Construction yards for building cranes, bridges, of the actual manufacture of the product by production roofing structures, etc., form another and entirely dif- machinery. ferent category of workshops. In the mass production The skilled workshop technician is perhaps best of consumer goods workshop technology plays an im- characterized as the.man who can read a drawing and portant part in the manufacture of production tools, who, with his machines and tools, can make whatever such as special machine tools, punches and dies. Work- is described in the drawing. We invariably find him at shop techniques are also indispensable to research. the interface between design and production, usually Scientific and medical equipment,' telecomrnunica- operating a machine-tool or lathe, or perhaps in the tion systems and equipment used for national defence assembly shop, using the drawings to assemble the and transport, are all examples of products that often parts that make a product. require the highest possible degree of mechanical refine- The processing of the flow of information referred to ment. It is no exaggeration to say that many of the new above is time-consuming and is moreover a potential fields opened up to science, such as nuclear technology, source of human error. The double delay involved in space travel and advanced medical methods, are acces- thinking out the right way of setting the machine by sible to science only provided workshop technology is reference to the drawing, and then checking and often able to supply the necessary equipment. rechecking the setting decided upon - for which the The vital importance of workshop technology to very Americans have coined the apt term "ear-scratching many industries stems from its role in the production of time" - makes productivity at the interface of design the capital goods that are essential for the running of and production unavoidably low. those industries. In the one-off manufacture of capital goods, little can be done about this state of affairs. As soon as the manu- A new viewpoint facture becomes repetitive, however, it becomes pos- In the last two decades numerical control has led to sible to make the effort required for the information a new, refreshing approach to workshop technology, processing just once-for the manufacture of a whole which has also shed light on problems outside the direct batch of products. The information must then be pro- field of application of this new method of processing. grammed into the setting of the machine, into the jigs In the jargon of cybernetics, which includes numerical and fixtures and other "hardware" in such a way that control as one. of its specializations, there is much to the product can be made with no need for a drawing say that is highly relevant to workshop technology. to be consulted. How far one can go in this direction depends on the size of the production run. In mass Prof. Ir. B. L. ten Horn is a Scientific Adviser with the Philips production it always pays to record the entire design Machine Workshops Division and is a Projessar Extraordinary of Delft Tee/mical University, He is also a member of the Board oJ Management of the Phllips Centre for Manufacturing Techniques, [1] H. Huizing, Numerieke besturing: integratie van construeren with special responsibility Jar Mechanical Process Operations. en produceren?, Ingenieur 80, W 197-203, 1968. 128 PHILlPS TECHNICAL REVIEW VOLUME 31 information in punches, dies, special machines, test and and fusion welding, brazing, bonding, etc., are of vital inspection devices, etc., so that the reading of drawings importance. is no longer necessary in the actual production and the In small-batch production by sheet-metal fabrication rate of production can be stepped up. it is usually preferable to make parts by bending flat The design/production interface has now been shifted pieces of sheet, since special tools are required to form to the toolmaking shop and the specialized machine compound-curved surfaces. In the aircraft industry it is shop, where we again find the skilled operator with his absolutely essential to be able to make surfaces with drawings, his universal tools and his flexible methods compound curvature. This industry has given us a of working. number of workshop methods that can be used to pro- The position of workshop technology between design duce small batches of products with compound-curved and production was undoubtedly recognized before the surfaces from sheet metal. advent of numerical control. Numerical control, and Toolmaking has always been a skill on its own. Tool- particularly the integration of design and production makers have learnt to think in shapes "the other way with the aid of modern information technology - com- round": a plastic product, for example, is for them a puter-aided design (CAD) and computer-aided manu- cavity in a mould. In machining operations this reversal facture (CAM) "", have forced engineers into more ad- of the shape of a product often creates intractable vanced thinking in this field and have provided us with problems of accessibility. To solve these problems tool- the terminology to define our ideas on this subject [21. makers have developed a number ofreversal techniques <The characteristic trends of the forty years reviewed such as hobbing, electroforming and spark machining. ü{this,article are rationalization and increase of scale, Finally, the whole of the data-processing activity in .. ' ". .. "_.,. which have frequently 'turned one-off production into' planning, tooling up, work study, etc. also constitutes batch.production and batch production into mass pro- an essential part of workshop technology. However, in duetion. Here the skilled operator-has- moved more and this historical survey we shall limit ourselves to the more towards the preparatien for production. purely engineering aspects of data-processing seen in In' the last fifteen years we have seen the emergence numerical control. of an entirely new development. The higher degree of Forty years of machining technology automation brought about by numerical control is no longer directed to.wards 'a shift in the labour-intensive The thirties were important years for machining. link in the production process from production itself High-speed steel was well established as a cutting to the manufacture of the means of production, but material. The cumbersome overhead drive systems toward;' automation of the information processing on (fig. 1) had disappeared or were disappearing from the spot, in order to -rationalize this difficult production most workshops. This led not only to better siting of phase as wel.I. the machines but also made it possible to supply as much power to the machine as was considered neces- Some important techniques sary. Metal-cutting or machining is still one of the princi- In 1927 the firm of Krupp demonstrated for the first . .11" ~ • pal subjectsof workshop.technology. The combination time the new "Widia" cutting material at the Leipzig of skilled operator and a universal metal-cutting Fair [31. This was what we now knowas cemented carbide machine remains the best means of making components or "hard metal". This event proved to be just as signi- of mechanisms direct from the information in the draw- ficant as the demonstration by F. W. Taylor and ing. The interplay of rotary and linear movements is M. White of high-speed steel at the Paris World Ex- applied in, such a way as to generate the shapes required hibition in 1900. The new material once again meant for the components of mechanisms that ,move in a an increase in cutting speed by a factor. of about five. related way. There are very few other shaping techni- Nevertheless, for reasons which we shall explain later ques that give sufficient accuracy for making, properly on, the new cutting material made disappointing pro- mating machine parts. gress in the thirties .. Mechanical metrology, including the theory of fits Meanwhile. the development of the older cutting and tolerances, is rightly regarded as belonging to material, high-speed- steel, received fres,h incentive be- workshop technology. Its connection with the manu- cause of the competition of hard metal.· The original facture of components and with assembly is obvious. invention by Taylor and White related rather to a new In sheet-metal work the distincticn between parts heat treatment for the already familiar tungsten-alloyed manufacture and assembly is often of little significance.