History
La evolución del hombre y en particular de su tecnología se ha basado en la utilización de herramientas, éstas eran como la prolongación de las manos humanas. Las primeras máquinas herramientas que aparecieron fueron los tornos y los taladros, en principio muy rudimentarios y manuales. El movimiento se proporcionaba manual y directamente al útil o al material que se quería trabajar. El arco de violín fue ese primer embrión de máquina herramienta cuyo origen se pierde en el tiempo.
En 1250 el avance permitió dejar las manos libres para el trabajo al poder imprimir el movimiento necesario con el pie mediante el artilugio de pedal y pértiga flexible.
A principios del siglo Leonardo da Vinci tenía diseñadas tres máquinas fundamentales para el acuñado de monedas: la laminadora, la recortadora") y la prensa de balancín. Sus diseños servirían de orientación para el desarrollo de máquinas en el futuro. Por esta época se descubrió la combinación del pedal con un vástago y una biela para conseguir el movimiento rotativo, que rápidamente se aplicó a las ruedas de afilar y poco más tarde a los tornos, a los cuales hubo que añadir un volante de inercia para poder evitar el efecto alto y bajo que producen los puntos muertos.
El torno va perfeccionándose y sobre 1658 se le añade el mandril y se comienza la mecanización de piezas de acero, en 1693 todavía no se había generalizado esa actividad.
En 1650, el matemático francés Blaise Pascal, enunció el principio de la prensa hidráulica, pero no se utilizaría para aplicaciones industriales hasta 1770, año en el que Bramach patentaba en Londres una prensa hidráulica. Años después se utilizaría en Francia para el acuñado de moneda.
Los fabricantes de relojes de los siglos y ya utilizaban tornos y roscadoras que les permitían obtener muy buenas precisiones. Destaca el diseño de roscadora hecho por Jesé Ramsden") en 1777.
Water as a source of movement
The water wheel that provided movement to the mills and hammers, pylons and bellows of the ironworks and smithies since the century and to the drilling machines, shortly after became the source of movement for the lathes and drilling machines that made up the workshops of the centuries and, until the arrival of the truly practical steam engine that could be built by Watt thanks to the boring machine that John Wilkinson made in 1775 that achieved a tolerance of "thickness of a sixpence coin in a diameter of 72 inches", sufficient precision for the adjustment of Watt's machine.
Steam as a source of movement, the Revolution
In the century the steam engine appeared, being one of the causes of the industrial revolution and the improvement of machine tools. The water wheel was replaced by the steam engine and with this the workshop acquired independence in its location. The movement is distributed through pulleys to all the machines that make it up, something that had already begun to be done with hydraulic wheels. Independence from the weather is also acquired, it is no longer dependent on the flow of the rivers.
From this moment a process would begin that lasts to this day: the need to design precise machines that allow other machines to be created. One of the main machine tool manufacturers of those times, the Englishman Henry Maudslay, would be the first to realize this need. It was he who introduced improvements that guaranteed very high precision and robustness. The use of metal benches and guide plates for the tool carriages and threaded-nut spindles were the foundation of the increase in precision and reliability.
In order to appreciate the precision of a machine in a depreciating job, you must have the precise tool to carry out the measurement. The important step was taken in 1805 by Maudslay, who five years earlier had made the first full metal lathe with a pattern guide spindle, the measuring device was a micrometer "Micrometer (instrument)") which he called Mr. Chancellor and could measure up to the thousandth of an inch.
During the century the development of the machine tool would be tremendous. The achievements achieved by Maudslay were the beginning of countless different machines that responded to the needs of the different manufacturing and construction industries with the machining of the parts they needed for their activity. Thus, faced, for example, with the need to plan iron plates, the first bridge planer was built. Maudslay's technical heirs, Richard Roberts), James Nasmyth and Joseph Whitworth, are the architects of this evolution of creation. Roberts builds the bridge brush, Nasmyth, the first filing machine, and in 1817 the German Dietrich Uhlhöm made the coin minting press, a great advance in coin manufacturing.
The presses were perfected in the second half of the century, when in 1867 the friction press appeared, from the Frenchman Cheret, and three years later the eccentric one from the house Blis & Williams of the United States.
Milling was born with the War of Independence of the English colonies in North America. The need to produce large quantities of weapons, which forced their mass production, led Ely Whitney to manufacture the first milling machine in 1818, which 30 years later would be perfected by engineer Howe who would provide it with movements in all three axes. He also developed a copying milling machine.
J. R. Brown introduced the divider in 1862, constituting an important advance. The milling machine reached its maximum development in 1884 when the Cincinnati company in the United States built the universal milling machine, which incorporated for the first time an axially deployable cylindrical ram. Another important step, before automation by numerical control, was the introduction of the rotating head that allows working in any plane between the horizontal and vertical, produced in 1894 by the Frenchman Huré.
The parallel lathe that Whitworth developed in 1850 has remained in force to the present day and only suffered the improvement of the Norton Box introduced in 1890 (Whitworth also developed the thread standard that bears his name).
In 1854, revolver turrets were introduced into lathes, thus giving rise to the revolver lathe, which makes it possible to carry out different operations with a single clamping of the piece. A variation of these was the introduction of continuous bar work. By 1898, automatic lathes had already been developed (which solved large productions of small pieces).
English leadership in the development and manufacture of machine tools passed to the Americans at the beginning of the century.
The development of the tool is linked to that of the machine itself. Thus, in 1865, new alloy steel tools came out, increasing the machining capacity, and in 1843 artificial grinding wheels were made to replace the obsolete sandstone.
The discovery of high speed steel in 1898 by Taylor and White increased cutting speed (multiplied by 3) and chip removal capacity (by more than 7).
The manufacture of grinding wheels develops grinding machines, both cylindrical and flat surface. The discovery of silicon carbide in 1891 by Edward Goodrich Acheson provided the opportunity to develop machines with high cutting speeds, thus opening the opportunity to build much more precise and powerful machines that were needed by the growing automobile industry.
The 19th would be the century of industrial development.
The 20th century, the great advance
The century must be divided into two distinct periods, the one that goes from the beginning of the century to the end of the Second World War and from this to the end of the century. The advances are very different, while in the first part the pace of the century, which was already high, is maintained, in the other the technology progresses very quickly, especially electronics, a new one, computing that allows, together with the knowledge of materials, changes that can be considered revolutionary.
Electricity as a source of movement had already been developed at the end of the 19th century. In the 20th century, alternating and direct current motors took the place of steam engines and were responsible for driving the general transmissions of industrial workshops.
By 1910, tolerances of thousandths of a meter began to be used and the micrometer "Micrometer (instrument)") became universal as a precision measuring device. The automobile industry acts as a driving force in the advancement of machine tool and precision measurement technologies. The demands for interchangeable parts and increasingly greater precision have led to important advances, such as the vertical spotting machine with a polar coordinate table developed by the Swiss Perrenond Jacot, which achieves previously unimaginable precision.
The incorporation of different technologies, such as bearing heads, ball bearings or ball screws, results in a considerable increase in productivity throughout the industry, especially in the automotive industry.
Advances in materials, essential for the manufacture of cutting tools, made an important contribution in 1927 with the appearance of the widia, presented at the Leipzig fair (Germany) by the Krupp company.
The movement and control systems are becoming more complicated and improved with the incorporation of local electric motors, even for the different axes of the same machine, hydraulic, pneumatic and electrical controls.
In the 1920s, the concept of autonomous machining units was developed and with it that of the transfer of the part to be machined and the union of both results in the transfer machine") which is a set of autonomous units.
In 1943, the marriage of Soviet scientists Boris and Natalia Lazarenko discovered and built the first EDM machines that were developed from 1950 and especially from 1955 when the Americans managed to create similar machines. EDM would have another spectacular advance when it had the electronic control technologies of the end of the century and wire EDM was developed.
In 1948, the first electronic controls for milling machines began to be developed. After research carried out by the Massachusetts Institute of Technology, a prototype was made and presented in 1952 (it was programmed using perforated tape and the machine could carry out simultaneous coordinated movements in the three axes).