Lathe is a machine tool that uses a turning tool to turn a rotating workpiece. Drills, reamers, reamers, taps, dies and knurling tools can also be used on the lathe for corresponding processing. Mainly used for lathes
1.1 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 while rotating it around its central axis. At first, people used two standing woods as a stand, set up the wood to be turned, used the elasticity of the branches to wind the rope onto the wood, pull the rope to pull the rope by hand or foot, and hold the knife to cut.
This ancient method has gradually evolved and developed into two or three turns of rope on a pulley. The rope is supported on an elastic rod bent into a bow, and the bow is pushed and pulled to rotate the processed object to turn it. This is the “bow lathe”.
1.2 The “bicycle lathe” driven by the crankshaft and flywheel in the Middle Ages In the Middle Ages, some people designed a “bicycle lathe” that rotates the crankshaft with a pedal and drives the flywheel, and then drives it to the main shaft to rotate it. In the middle of the 16th century, a French designer named Besson designed a lathe for turning screws that uses a screw rod to slide tools. Unfortunately, this type of lathe was not promoted.
1.3 The bedside box and chuck were born in the 18th century. In the 18th century, someone also designed a crankshaft that rotates the crankshaft with a foot pedal and a connecting rod. The rotary kinetic energy can be stored on a lathe on the flywheel and the workpiece can be directly rotated Developed into a rotating headboard, which is a chuck for holding workpieces.
1.4 The British Mozley invented the tool post lathe (1797). Among the stories of the invention of the lathe, the most notable was an English named Mozley, because he invented the epoch-making tool post lathe in 1797. This lathe has a precision lead screw and interchangeable gears.
B. Mozley was born in 1771, and at the age of 18 he was a powerful assistant to the inventor Brammer. It is said that Brammer had always been doing farm work. At the age of 16, he suffered a disability in his right ankle because of an accident, and was forced to switch to carpentry with less mobility. His first invention was a toilet in 1778. Mozley began to help Brammer design hydraulic presses and other machinery. He did not leave Brammer until he was 26 years old, because Brammer ruthlessly rejected Moliz’s proposal. Requests to increase wages to more than 30 shillings per week.
In the year Mozley left Brammer, he made the first threaded lathe, an all-metal lathe with a tool holder and tailstock that could move along two parallel guides. The guide surface of the guide rail is triangular. When the spindle rotates, the lead screw is driven to move the tool holder laterally. This is the main mechanism of modern lathes, with which precision metal screws of any pitch can be machined.
Twenty-three years later, Mozley built a more complete lathe in his own workshop. The gears on it can be replaced with each other, which can change the feed speed and the pitch of the thread being processed. In 1817, another Englishman Roberts adopted a four-stage pulley and back wheel mechanism to change the spindle speed. Soon, larger lathes were also introduced, which contributed to the invention of steam engines and other machinery.
1.5 The birth of various special lathes In order to improve the degree of mechanization and automation, in 1845, the American Fitch invented the turret lathe; in 1848, the United States turned back lathes; in 1873, the American Spencer made a single-axis automatic Lathes, which were soon made into three-axis automatic lathes; in the early 20th century, lathes with gearboxes driven by separate motors appeared. Due to the invention of high-speed tool steel and the application of electric motors, the lathe has been continuously improved and finally reached the modern level of high speed and high precision.
After the First World War, due to the needs of the arms, automobile and other machinery industries, various efficient automatic lathes and specialized lathes developed rapidly. In order to increase the productivity of small batches of workpieces, lathes with hydraulic profiling devices were popularized in the late 1940s, and at the same time, multi-tool lathes were also developed. In the 1950s, program-controlled lathes with perforated cards, latch plates and dials were developed. Numerical control technology began to be used on lathes in the 1960s, and it developed rapidly after the 1970s.
1.6 Classification of lathes Lathes are divided into various types according to their uses and functions.
The lathe has a wide range of processing objects, and the adjustment range of the spindle speed and feed amount is large. It can process the inner and outer surfaces, end faces and internal and external threads of the workpiece. This lathe is mainly operated manually by the workers, which has low production efficiency and is suitable for single-piece, small-batch production and repair workshops.
The turret lathe and rotary lathe have a turret tool holder or a return tool holder that can hold multiple tools. The workers can use different tools to complete a variety of processes in a single clamping of the workpiece, which is 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, and repeatedly process a batch of the same workpiece, which is suitable for large-scale and mass production.
Multi-tool semi-automatic lathes are divided into single-axis, multi-axis, horizontal and vertical. The single-axis horizontal layout is similar to that of ordinary lathes, but the two sets of tool holders are installed at the front, back, or top of the spindle, respectively, for machining discs, rings, and shafts. The productivity is 3 to 5 times higher than that of ordinary lathes.
The profiling lathe can imitate the shape and size of the prototype or the sample automatically to complete the processing cycle of the workpiece. It is suitable for the small batch and batch production of more complex workpieces, and the productivity is 10-15 times higher than that of the ordinary lathe. There are multi-tool post, multi-axis, chuck, vertical and other types.
The main axis of a vertical lathe is perpendicular to the horizontal plane, the workpiece is clamped on a horizontal rotary table, and the tool holder is moved on the beam or column. It is suitable for processing larger, heavier and difficult to install workpieces on ordinary lathes. Generally it is divided into two categories: single column and double column.
The shovel tooth lathe is periodically reciprocating in the radial direction while turning. It is used to form the tooth surface of a milling cutter, a hob, etc. A small grinding wheel, usually with a shovel attachment, is used to grind the tooth surface.
Special lathes are lathes used to process specific surfaces of certain types of workpieces, such as crank lathes, camshaft lathes, wheel lathes, axle lathes, roll lathes, and ingot lathes.
Combined lathe is mainly used for turning, but after adding some special parts and accessories, it can also perform boring, milling, drilling, inserting, grinding and other processing. It has the characteristics of “one machine and multiple functions” and is suitable for engineering vehicles, ships or mobiles. Repair work at a repair station.