A machine tool is a machine that processes metal blanks into machine parts. It is a machine that manufactures machines, so it is also called "working machine" or "tool machine", and is customarily referred to as a machine tool. So what are the categories of machine tools? There are many ways to process mechanical parts in modern machinery manufacturing: in addition to cutting, there are also casting, forging, welding, stamping, extrusion, etc. The final machining is done by cutting on the machine tool. In general machine manufacturing, the processing workload undertaken by machine tools accounts for 40%-60% of the total machine manufacturing workload, and machine tools play an important role in the modernization of the national economy. Machine tools are mainly classified according to processing methods and cutting tools used. According to the machine tool model formulating method formulated by the country, machine tools are divided into 11 categories: lathes, drilling machines, boring machines, grinding machines, gear processing machines, thread processing machines, milling machines, planing and slotting machines, drawing machines, etc. Beds, saws and other machine tools. In each type of machine tool, it is divided into several groups according to the process range, layout type and structural performance, and each group is divided into several series. The following is a brief introduction to some lathes.
Today we will introduce the lathe first.
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A lathe is a machine tool that mainly uses a turning tool to turn a rotating workpiece. Drills, reamers, reamers, taps, dies and knurling tools can also be used for corresponding processing on the lathe. Lathes are mainly used to process shafts, disks, sleeves and other workpieces with rotating surfaces, and are the most widely used machine tools in machinery manufacturing and repair factories.
1. The "bow lathe" of ancient pulleys and bow rods As early as the ancient Egyptian era, people had invented the technology of turning wood with a tool when rotating it around its central axis. At first, people used two standing logs as supports to set up the wood to be turned, used the elasticity of the branches to roll the rope to the wood, pulled the rope by hand or pedal to turn the wood, and cut with a knife in hand.
This ancient method gradually evolved into two or three loops of rope on the pulley, and the rope was mounted on an elastic rod bent into a bow, and the bow was pushed and pulled back and forth to rotate the processed object for turning. This is the "bow lathe".
2. Medieval "pedal lathes" driven by crankshafts and flywheels. In the Middle Ages, someone designed a "pedal lathe" that used pedals to rotate the crankshaft and drive the flywheel, and then transmitted to the main shaft to make it rotate. In the middle of the 16th century, a designer named Besson in France designed a lathe for turning screws that used a screw rod to slide the tool. Unfortunately, this lathe was not popularized.
3. Bedside boxes and chucks were born in the 18th century. In the 18th century, someone designed a kind of pedal and connecting rod to rotate the crankshaft, which can store the rotational kinetic energy on the lathe on the flywheel, and directly rotate the crankshaft. Workpieces evolved to a rotating headstock, which is a chuck that holds the workpiece.
4. In 1797, the British Maudsley invented the epoch-making tool post lathe, which has a precise lead screw and interchangeable gears.
Born in 1771, Maudsley was the right-hand man of the inventor Brammer when he was 18 years old. It is said that Brammer had been doing farm work all the time. When he was 16 years old, his right ankle was disabled due to an accident, so he had to switch to woodworking with less mobility. His first invention was the flush toilet in 1778. Maudsley began to help Brammer design hydraulic presses and other machinery until he was 26 years old. A request for wages to be increased above 30 shillings per week.
In the year that Maudsley left Brammer, he built the first threading lathe, an all-metal lathe with tool and tailstocks that moved along two parallel guideways. The guide surface of the guide rail is triangular, and when the main shaft rotates, it drives the lead screw to move the tool holder laterally. This is the main mechanism of modern lathes, which can be used to make precision metal screws with any pitch.
Three years later, Mozley built a more complete lathe in his own workshop. The gears on it could be replaced with each other, and the feed speed and pitch of the processed threads could be changed. In 1817, another Englishman, Roberts, used a four-stage pulley and back wheel mechanism to change the spindle speed. Soon, larger lathes also came out, and made great contributions to the invention of the steam engine and other machinery.
5. The birth of various special lathes In order to improve the degree of mechanization and automation, Fitch in the United States invented the turret lathe in 1845; in 1848, the return wheel lathe appeared in the United States; Automatic lathes, and soon he made a three-axis automatic lathe; at the beginning of the 20th century, a lathe with a gear gearbox driven by a separate motor appeared. Due to the invention of high-speed tool steel and the application of electric motors, lathes have been continuously improved, and finally reached the modern level of high speed and high precision.
After the First World War, various high-efficiency automatic lathes and specialized lathes developed rapidly due to the needs of the munitions, automobile and other machinery industries. In order to improve the productivity of small batches of workpieces, lathes with hydraulic profiling devices were promoted in the late 1940s, and at the same time, multi-tool lathes were also developed. In the mid-1950s, program-controlled lathes with punched cards, latch plates, and dials were developed. CNC technology began to be used in lathes in the 1960s and developed rapidly after the 1970s.
6. Lathes are divided into various types according to their uses and functions.
Ordinary lathes have a wide range of processing objects, a large adjustment range of spindle speed and feed rate, and can process the internal and external surfaces, end surfaces, and internal and external threads of the workpiece. This kind of lathe is mainly operated by workers manually, and the production efficiency is low. It is suitable for single-piece, small-batch production and repair workshops.
Turret lathes and rotary lathes have turret tool holders or rotary tool holders that can hold multiple tools. Workers can use different tools to complete various processes in one clamping of the workpiece, and are suitable for batch production.
The automatic lathe can automatically complete the multi-process processing of small and medium-sized workpieces according to a certain program, can automatically load and unload materials, and repeatedly process a batch of the same workpieces, which is suitable for mass production.
Multi-tool semi-automatic lathes are divided into single-axis, multi-axis, horizontal and vertical. The layout of the single-axis horizontal type is similar to that of ordinary lathes, but the two sets of tool holders are respectively installed in the front, back, or up and down of the main shaft, and are used to process disks, rings, and shafts. Its productivity is 3 to 5 times higher than that of ordinary lathes.
The copy lathe can imitate the shape and size of the template or sample, and automatically complete the processing cycle of the workpiece. It is suitable for small batch and batch production of workpieces with complex shapes, and its productivity is 10 to 15 times higher than that of ordinary lathes. There are multi-turret, multi-axis, chuck type, vertical type and other types.
The spindle of the vertical lathe is perpendicular to the horizontal plane, the workpiece is clamped on the horizontal rotary table, and the tool holder moves on the beam or column. It is suitable for processing larger, heavier workpieces that are difficult to install on ordinary lathes, and is generally divided into two categories: single column and double column.
While the shovel tooth lathe is turning, the tool holder periodically reciprocates radially, which is used to form the tooth surface of forklift milling cutters, hobs, etc. Usually with a relief grinding attachment, a small grinding wheel driven by a separate motor relieves the tooth surface.
Specialized lathes are lathes used to process specific surfaces of certain types of workpieces, such as crankshaft lathes, camshaft lathes, wheel lathes, axle lathes, roll lathes, and ingot lathes.
The combined lathe is mainly used for turning, but with some special parts and accessories, it can also perform boring, milling, drilling, inserting, grinding and other processing. It has the characteristics of "one machine with multiple functions" and is suitable for engineering vehicles, ships or mobile Repair work on the repair station.