The Development History Of Machine Tools
In the prototype of the machine tool in the fifteenth century, due to the need to manufacture clocks and weapons, threaded lathes and gear processing machines used by watchmakers, as well as hydraulically driven barrel boring machines, hadappeared. Around 1501, Italian Leonardo da Vinci drew conceptual sketches of lathes, boring machines, threading machines and internal grinders. Among them, there were new mechanisms such as cranks, flywheels, tips and bearings. The structure of a grinder is also contained in the "Tiangong Kaiwu" published in the Ming Dynasty of China. The iron plate is rotated by the pedal method, sand and water are added to cut the jade.
The industrial revolution led to the production and improvement of various machine tools. The industrial revolution of the eighteenth century promoted the development of machine tools. In 1774, the British Wilkinson (full name John Wilkinson) invented a more precise barrel boring machine. The following year, he used the cylinder bored by this barrel boring machine to meet the requirements of the Watt steam engine. In order to boring larger cylinders, he built a water-wheel-driven cylinder boring machine in 1775, which promoted the development of steam engines. Since then, the machine tool began to be driven by a steam engine through the crankshaft.
In 1797, a lathe created by the British Mozley was driven by a screw, which can realize motorized feed and thread turning. This is a major change in the structure of the machine tool. Mozley is therefore known as "the father of the British machine tool industry."
In the 19th century, due to the promotion of textile, power, transportation machinery and munitions production, various types of machine tools appeared one after another. In 1817, the British Roberts created a planer; in 1818, American Whitney (full name Eli Whitney) made a horizontal milling machine; in 1876, the United States made a universal cylindrical grinder; in 1835 and 1897 successively Invented the gear hobbing machine and the gear shaping machine.
The center of industrial technology development has quietly moved from Britain to the United States since the nineteenth century. Among those who have taken the prestige of British technology into the past, Whitney is the best. Whitney was brilliant and visionary, and he was the first to develop a system as a replaceable part for mass production. The Whitney Engineering Company, which is still very active, successfully developed a turret type hexagonal lathe as early as the 1840s. This kind of lathe came out with the complexity and refinement of the workpiece production. In this kind of lathe, a winch is installed, and all the necessary tools are installed on the winch. In this way, the turret is fixed by rotating the tool. , You can turn the tool to the desired position.
With the invention of the electric motor, machine tools began to be driven by electric motors first, and then driven by separate electric motors.
In the early twentieth century, in order to process higher precision workpieces, fixtures and thread processing tools, coordinate boring machines and thread grinders were successively created. At the same time, in order to meet the needs of mass production in industries such as automobiles and bearings, various automatic machine tools, profiling machine tools, modular machine tools and automatic production lines have been developed.
In 1900, it entered a period of precision. From the end of the 19th century to the beginning of the 20th century, a single lathe has gradually evolved into a milling machine, a planer, a grinder, a drilling machine, etc. These main machine tools have been basically finalized, thus creating conditions for the precision machine tools and production mechanization and semi-automation in the early 20th century. .
In the first 20 years of the 20th century, people mainly revolved around milling machines, grinders and assembly lines. Due to the production requirements of automobiles, airplanes and their engines, precision and automatic milling machines and grinders are urgently needed when processing a large number of parts with complex shapes, high precision and high finish. Due to the advent of the multi-helical cutter edge milling cutter, the vibration and smoothness generated by the single-edge milling cutter are basically solved, and the difficulty of the milling machine not being developed, making the milling machine an important equipment for processing complex parts.
Ford, known as the "father of automobiles" by the world, puts forward that cars should be "lightweight, strong, reliable and cheap." In order to achieve this goal, high-efficiency grinders must be developed. For this reason, American Norton used emery and corundum in 1900 to make large-diameter and wide grinding wheels, as well as rigid and strong heavy-duty grinders. The development of grinding machines has brought machinery manufacturing technology into a new stage of precision.
Entered into a semi-automated period in 1920. In the 30 years after 1920, mechanical manufacturing technology entered a semi-automated period, hydraulic and electrical components were gradually applied in machine tools and other machinery. In 1938, the hydraulic system and electromagnetic control not only promoted the invention of a new type of milling machine, but also promoted its use on machine tools such as planers. After the 1930s, the limit switch-solenoid valve system was almost used for automatic control of various machine tools.
In 1950, it entered the period of automation. After the Second World War, due to the emergence of CNC and group control machine tools and automatic lines, the development of machine tools began to enter the period of automation. After the invention of the electronic computer, the numerical control machine tool uses the principle of digital control to store the processing procedures, requirements and operation numbers and text codes of the tool as information, and controls the machine tool according to the instructions issued by it, and performs processing according to the established requirements.
The world's first CNC machine tool (milling machine) was born (1951). The plan for the CNC machine tool was proposed to the US Air Force by Parsons (full name John Parsons) of the United States when he was developing a blade processing machine for inspecting the profile profile of aircraft propeller blades. With the participation and assistance of MIT, it finally succeeded in 1949. In 1951, they formally produced the first prototype of the electronic tube CNC machine tool, which successfully solved the automation problem of the processing of complex parts of multiple varieties and small batches. Later, on the one hand, the principle of numerical control has expanded from milling machines to milling and boring machines, drilling machines, and lathes; on the other hand, it has transitioned from electron tubes to transistors and integrated circuits. In 1958, the United States developed a machining center that can automatically change tools for multi-process processing.
The world's first CNC production line was born in 1968. The British Maurings Machinery Company developed the first automatic line composed of CNC machine tools. Soon, the General Electric Company of the United States proposed that "the prerequisite for factory automation is the numerical control of the parts processing process and the program control of the production process." Thus, by the mid-1970s, automated workshops appeared, and automated factories had begun to be built. From 1970 to 1974, due to the widespread use of small computers in machine tool control, three technological breakthroughs occurred. The first time was a direct digital controller, which enabled a small electronic computer to control multiple machine tools at the same time, and "group control" appeared; the second time was computer-aided design, which used a light pen to design and modify the design and calculation program; The third time is to feed back and automatically change the processing amount and cutting speed according to the actual processing conditions and unexpected changes, then a machine tool with an adaptive control system appears.
After more than 100 years of ups and downs, the family of machine tools has matured day by day and has truly become the "worker machine" in the mechanical field.