Abstract: Machine tools are mainly classified according to processing methods and cutting tools used. According to the machine tool model compilation method formulated by the country, machine tools are divided into 11 categories: lathes, drilling machines, boring machines, grinders, gear processing machine tools, threads Processing machine tools, milling machines, planing machines, broaching machines, sawing machines and other machine tools. In each type of machine tool, it is divided into several groups according to the process scope, layout type and structural performance, and each group is divided into several series (series). What are the classifications of machine tools? What are the detailed model regulations of machine tools

A machine tool is a machine that processes metal blanks into machine parts. It is a machine for manufacturing machines, so it is also called a "work machine" or a "machine tool", and is customarily referred to as a machine tool. There are many methods for processing mechanical parts in modern machinery manufacturing: in addition to cutting, there are also casting, forging, welding, stamping, extrusion, etc. Parts that require higher precision and finer surface roughness generally need to be machined. The machine tool uses cutting methods for final processing. In general machine manufacturing, the processing workload undertaken by machine tools accounts for 40%-60% of the total machine manufacturing workload. Machine tools play an important role in the modernization of the national economy.

(1) Ordinary machine tools

1. Lathe

A lathe is a machine tool that mainly uses turning tools to turn rotating workpieces. Drills, reamers, reamers, taps, die and knurling tools can also be used on lathes for corresponding processing. Lathes are mainly used to process shafts, discs, sleeves and other workpieces with rotating surfaces. They are the most widely used type of machine tools in machinery manufacturing and repair factories.

1.1 The "bow lathe" of ancient pulleys and bow-shaped rods As early as the ancient Egyptian times, people had invented the technology of turning wood with tools while rotating it around its central axis. At first, people used two standing timbers as supports to set up the wood to be turned, used the elasticity of the branches to roll the rope onto the wood, pulled the rope by hand or foot to turn the wood, and held a knife to cut.

This ancient method gradually evolved into winding a rope around a pulley two or three times. The rope was placed on an elastic rod bent into a bow shape. The bow was pushed and pulled back and forth to rotate the processed object for turning. It is the "bow lathe".

1.2 The "pedal lathe" with crankshaft and flywheel transmission in the Middle Ages. In the Middle Ages, someone designed a "pedal lathe" that used a pedal to rotate the crankshaft and drive the flywheel, and then transmitted 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 used a screw bar to slide the tool. Unfortunately, this lathe was not widely used.

1.3 In the 18th century, bedside boxes and chucks were born. In the 18th century, someone else designed a lathe that used a pedal and connecting rod to rotate the crankshaft and store the rotational kinetic energy on the flywheel. and developed from directly rotating workpieces to rotating headstocks, which are chucks used to hold workpieces.

1.4 The Englishman Maudsley invented the tool holder lathe (1797). Among the stories of the invention of the lathe, the most eye-catching one is an Englishman named Maudsley, because he invented it in 1797 Invented the epochal tool-holder lathe with precision lead screws and interchangeable gears.

Maudsley was born in 1771. When he was 18 years old, he was the inventor Brammer's right-hand man. It is said that Bramer had always been doing farm work. When he was 16 years old, an accident caused his right ankle to be disabled, so he had to switch to woodworking with low mobility. His first invention was the flush toilet in 1778. Maudsley began to help Brammer design hydraulic presses and other machinery. He did not leave Brammer until he was 26 years old because Bramer rudely rejected Maurizio's proposal. A request for an increase in wages above 30 shillings per week.

The year Maudsley left Bramer, he made the first thread lathe, an all-metal lathe with a tool that could move along two parallel guide rails. seat and tailstock. The guide surface of the guide rail is triangular, and when the spindle rotates, it drives the screw to move the tool holder laterally. This is the main mechanism of modern lathes. With this lathe, precision metal screws of any pitch can be turned.

Three years later, Maudsley built a more complete lathe in his own workshop, with interchangeable gears that could change the feed speed and the pitch of the thread being processed. In 1817, another Englishman, Roberts, used a four-stage pulley and back pulley mechanism to change the spindle speed. Soon, larger lathes also came out, making great contributions 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, Fitch in the United States invented the turret lathe in 1845; in 1848, the turning lathe appeared in the United States; in 1873, Spencer in the United States A single-axis automatic lathe was made, and soon he made a three-axis automatic lathe; in the early 20th century, lathes with gear transmissions driven by separate motors 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 World War I, various high-efficiency automatic lathes and specialized lathes developed rapidly due to the needs of the arms, automobile and other machinery industries. In order to improve the productivity of small batches of workpieces, lathes with hydraulic profiling devices were popularized in the late 1940s. At the same time, multi-tool lathes were also developed. In the mid-1950s, program-controlled lathes with punch cards, latch plates, dials, etc. were developed. CNC technology began to be used in lathes in the 1960s and developed rapidly after the 1970s.

1.6 Classification of lathes Lathes are divided into many types according to their uses and functions.

Ordinary lathes have a wide range of processing objects, a wide adjustment range for spindle speed and feed, and can process the internal and external surfaces, end faces and internal and external threads of the workpiece. This type of lathe is mainly operated manually by workers and has low production efficiency. It is suitable for single-piece, small-batch production and repair workshops.

Turret lathes and rotary lathes have a turret tool holder or a rotating tool holder that can hold multiple tools. Workers can use different tools to complete multiple processes in one clamping of the workpiece. It is suitable for for batch production.

Automatic lathes can automatically complete multi-process processing of small and medium-sized workpieces according to certain procedures. They can automatically load and unload materials and repeatedly process a batch of the same workpieces. They are suitable for mass and mass production.

Multi-tool semi-automatic lathes are divided into single-axis, multi-axis, horizontal and vertical types. The layout of the single-axis horizontal lathe is similar to that of an ordinary lathe, but the two sets of tool holders are installed at the front, rear or upper and lower of the spindle. They are used to process discs, rings and shaft workpieces. Its productivity is 3 to 5 times higher than that of ordinary lathes.

The profiling lathe can imitate the shape and size of the template or prototype and automatically complete the processing cycle of the workpiece. It is suitable for small batch and batch production of workpieces with complex shapes. The productivity is 10 to 15 times higher than that of ordinary lathes. times. There are multiple tool holders, multi-axis, chuck type, vertical type and other types.

The spindle of a vertical lathe is perpendicular to the horizontal plane, the workpiece is clamped on a horizontal rotary table, and the tool rest moves on the beam or column. It is suitable for processing larger, heavier workpieces that are difficult to install on ordinary lathes. It is generally divided into two categories: single column and double column.

While the shovel tooth lathe is turning, the tool holder periodically makes radial reciprocating motion, which is used to form the tooth surfaces of forklift milling cutters, hobs, etc. Usually with a relief grinding attachment, a small grinding wheel driven by a separate electric 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 steel ingot lathes.

The combined lathe is mainly used for turning processing, but with the addition of some special parts and accessories, it can also be used for boring, milling, drilling, inserting, grinding and other processing. It has the characteristics of "one machine with multiple functions" and is suitable for Repair work on engineering vehicles, ships or mobile repair stations.

The application characteristics of SAJ inverter for machine tools

1. Large low-frequency torque and stable output

2. High-performance vector control

3. Fast dynamic response of torque and high speed stabilization accuracy

4. Fast deceleration and parking speed

5. Strong anti-interference ability

Although the factory handicraft industry is relatively It is backward, but it has trained and created many technicians. Although they are not experts in

2. Boring machine

door manufacturing machines, they can make Various hand tools, such as knives, saws, needles, drills, cones, grinders, shafts, sleeves, gears, bed frames, etc. In fact, machines are assembled from these parts.

2.1 The earliest boring machine designer - Leonardo da Vinci's boring machine is called the "Mother of Machinery". Speaking of boring machines, we must first talk about Leonardo da Vinci. This legendary figure may have been the designer of the earliest boring machine used for metal processing. The boring machine he designed was powered by water or a foot pedal. The boring tool rotated close to the workpiece, and the workpiece was fixed on a moving table driven by a crane. In 1540, another painter painted a painting of "The Art of Pyrotechnics", which also had the same picture of a boring machine. The boring machine at that time was specially used for finishing hollow castings.

2.2 The first boring machine was born for the processing of cannon barrels (Wilkinson, 1775). In the 17th century, due to military needs, the cannon manufacturing industry developed very rapidly. How to manufacture cannons The barrel has become a big problem that people need to solve urgently.

The world's first true boring machine was invented by Wilkinson in 1775. In fact, to be precise, Wilkinson's boring machine was a drilling machine capable of precision machining of cannons. It was a hollow cylindrical boring bar with both ends mounted on bearings.

Wilkinson was born in the United States in 1728. When he was 20 years old, he moved to Staffordshire and built Bilston's first ironmaking furnace. For this reason, Wilkinson was known as the "Master Blacksmith of Staffordshire". In 1775, 47-year-old Wilkinson worked hard in his father's factory and finally created a new machine that could drill cannon barrels with rare precision. Interestingly, after Wilkinson died in 1808, he was buried in a cast iron coffin designed by himself.

2.3 Boring machines made important contributions to Watt’s steam engine. Without the steam engine, the first wave of the Industrial Revolution would not have been possible. As for the development and application of the steam engine itself, in addition to the necessary social opportunities, some technical prerequisites cannot be ignored, because manufacturing the parts of the steam engine is far from being as easy as a carpenter cutting wood. It requires making some special metal parts. The shape, and the processing precision requirements are very high, which cannot be achieved without the corresponding technical equipment. For example, when manufacturing cylinders and pistons of steam engines, the accuracy of the outer diameter required in the piston manufacturing process can be measured from the outside while cutting. However, to meet the accuracy requirements of the inner diameter of the cylinder, it is not easy to achieve it using general processing methods. .

Smeaton was the best mechanical technician of the eighteenth century. Smeaton designed 43 pieces of waterwheel and windmill equipment. When making a steam engine, the most difficult thing for Smeaton was processing the cylinder. It is quite difficult to process the inner circle of a large cylinder into a circle. To this end, Smeaton built a special machine tool for cutting the inner circle of the cylinder at the Karen Iron Works. This kind of boring machine driven by a water wheel has a cutter installed on the front end of its long axis. This cutter can rotate in the cylinder, so that its inner circle can be machined. Since the tool is installed at the front end of the long shaft, problems such as shaft deflection will occur. Therefore, it is very difficult to machine a truly round cylinder. To this end, Smeaton had to change the position of the cylinder many times for processing.

For this problem, the boring machine invented by Wilkinson in 1774 played a big role. This kind of boring machine uses a water wheel to rotate the material cylinder and push it towards the centrally fixed tool. Due to the relative movement between the tool and the material, the material is bored into a cylindrical hole with high precision. At that time, a boring machine was used to make a cylinder with a diameter of 72 inches, and the error was no more than the thickness of a sixpence coin.

Measured by modern technology, this is a big error, but under the conditions at the time, it was already very difficult to reach this level.

However, Wilkinson’s invention did not apply for patent protection, and people copied it and installed it. In 1802, Watt also talked about Wilkinson's invention in his book and copied it in his Soho iron factory. Later, Watt also used Wilkinson's magical machine when manufacturing cylinders and pistons for steam engines. It turns out that for the piston, you can measure the size outside and cut it at the same time, but for the cylinder it is not that simple and you have to use a boring machine. At that time, Watt used a water wheel to rotate the metal cylinder and push the centrally fixed tool forward to cut the inside of the cylinder. As a result, the error of the 75-inch diameter cylinder was less than the thickness of a coin. It's very advanced.

2.4 The birth of the table-lifting boring machine (Hutton, 1885) In the following decades, many improvements were made to Wilkinson's boring machine. In 1885, Hutton in the UK manufactured a table-lifting boring machine, which has become the prototype of modern boring machines.

3. Milling machine

In the 19th century, the British invented boring machines and planers to meet the needs of the industrial revolution such as steam engines, while Americans focused on the invention of milling machines in order to produce a large number of weapons. . A milling machine is a machine with milling cutters of different shapes, which can cut workpieces with special shapes, such as spiral grooves, gear shapes, etc.

As early as 1664, the British scientist Hooke used a rotating circular tool to create a machine for cutting. This could be regarded as a primitive milling machine, but society did not make any progress at that time. Enthusiastic response. In the 1840s, Pratt designed the so-called Lincoln milling machine. Of course, it was the American Whitney who truly established the status of milling machines in machine manufacturing.

3.1 The first ordinary milling machine (Whitney, 1818) In 1818, Whitney built the world's first ordinary milling machine, but the patent for the milling machine was obtained by the British Bodmer ( The inventor of the gantry planer with a knife feeding device was the first to "obtain" it in 1839. Because the cost of milling machines was too high, not many people were interested in it at that time.

3.2 The first universal milling machine (Brown, 1862) After a period of silence, milling machines became active again in the United States. In contrast, Whitney and Pratt can only be said to have laid the foundation for the invention and application of milling machines. The real credit for inventing milling machines suitable for various factory operations should belong to American engineer Joseph Brown.

In 1862, Brown of the United States manufactured the world's earliest universal milling machine. This milling machine was an epoch-making initiative in that it was equipped with a universal indexing plate and a comprehensive milling cutter. The worktable of the universal milling machine can rotate at a certain angle in the horizontal direction and is equipped with accessories such as an end milling head. The "Universal Milling Machine" he designed was a great success when it was exhibited at the 1867 Paris Exposition. At the same time, Brown also designed a form milling cutter that would not deform after grinding, and then manufactured a grinding machine for milling cutters, bringing the milling machine to its current level.

4. Planer

In the process of invention, many things are often complementary and interlocking: in order to make a steam engine, the boring machine is needed to help; after the steam engine was invented, From the perspective of process requirements, gantry planers have begun to be called for again. It can be said that it was the invention of the steam engine that led to the design and development of "work machines" from boring machines and lathes to gantry planers. In fact, a planer is a "plane" used to plan metal.

4.1 Gantry planer for processing large flat surfaces (1839) Due to the need for flat surface processing of steam engine valve seats, many technicians began research in this area starting from the early 19th century, including Richard Robert, Richard Pratt, James Fox and Joseph Clement, etc., began to independently manufacture gantry planers within 25 years starting in 1814. This type of gantry planer fixes the workpiece on a reciprocating platform, and the planer cuts one side of the workpiece. However, this type of planer does not yet have a knife feeding device and is in the process of transforming from a "tool" to a "machine".

By 1839, a British man named Bodmer finally designed a gantry planer with a knife feeding device.

4.2 The bull-head planer for processing small planes. Another British man, Nesmith, invented and manufactured the bull-head planer for processing small planes within 40 years from 1831. It can fix the processing object on the bed, and the tool Make a round trip motion.

Since then, due to the improvement of tools and the emergence of electric motors, gantry planers have developed in the direction of high-speed cutting and high precision on the one hand, and in the direction of large-scale on the other hand.

5. Grinding machine

Grinding is an ancient technology that humans have known since ancient times. In the Paleolithic Age, this technology was used to grind stone tools. Later, with the use of metal utensils, the development of grinding technology was promoted. However, the design of grinding machines worthy of the name is still a modern thing. Even in the early 19th century, people still grinded by rotating natural grinding stones and letting them contact the workpiece.

5.1 The first grinding machine (1864) In 1864, the United States made the world's first grinding machine, which installed a grinding wheel on the slide tool holder of the lathe and made it have automatic transmission. a device. Twelve years later, Brown in the United States invented a universal grinder that was close to a modern grinder.

5.2 Artificial grinding stones - the birth of the grinding wheel (1892), the demand for artificial grinding stones also rose. How to develop a grinding stone that is more wear-resistant than natural grinding stone? In 1892, the American Acheson successfully trial-produced silicon carbide made of coke and sand, which is an artificial grindstone now called C abrasive; two years later, A abrasive with alumina as the main component was trial-produced. was successful, and in this way, the grinder became more widely used.

Afterwards, due to further improvements in bearings and guide rails, grinding machines became more and more precise and developed in a professional direction. Internal grinding machines, surface grinding machines, roller grinding machines, gear grinding machines, and universal grinding machines appeared. etc.

6. Drilling machine

6.1 Ancient drilling machine - "Gong Lail" drilling technology has a long history. Archaeologists have now discovered that humans invented devices for drilling holes in 4000 BC. The ancients set up a beam on two upright columns, hung a rotating awl downward from the beam, and then used a bow string to wrap the awl to rotate, so that holes could be drilled in wood and stone. Soon, people also designed a hole-punching tool called a "window", which also used elastic bow strings to rotate the awl.

6.2 The first drill press (Whitworth, 1862) Around 1850, the German Martignoni first made a twist drill for metal drilling; in London, England in 1862 At the International Exposition held in 1998, the British man Whitworth exhibited a power-driven cast iron cabinet frame drilling machine, which became the prototype of the modern drilling machine.

After that, various drilling machines appeared one after another, including radial drilling machines, drilling machines equipped with automatic feed mechanisms, multi-axis drilling machines that can drill multiple holes at one time, etc. Due to improvements in tool materials and drill bits, as well as the use of electric motors, large, high-performance drilling machines were finally manufactured.

(2) Technical and economic indicators of machine tools

The equipment used to manufacture machine parts is generally called metal cutting machine tools, or machine tools for short.

The quality of the machine tool itself directly affects the quality of the machine being manufactured. There are many aspects to measuring the quality of a machine tool, but it mainly requires good craftsmanship, high degree of serialization, generalization, standardization, simple structure, light weight, reliable operation, and high productivity. The specific indicators are as follows:

1. Process possibility

Process possibility refers to the ability of the machine tool to adapt to different production requirements. General-purpose machine tools can complete multi-process processing of various parts within a certain size range. The process possibilities are wide, so the structure is relatively complex and suitable for single-piece and small-batch production. Special-purpose machine tools can only complete specific processes of one or several parts. Their process possibilities are narrow and they are suitable for mass production. They can improve productivity, ensure processing quality, simplify machine tool structures, and reduce machine tool costs.

2. Processing accuracy and surface roughness

To ensure the accuracy and surface roughness of the parts being processed, the machine tool itself must have certain geometric accuracy, motion accuracy, transmission accuracy and dynamics Accuracy.

(1) Geometric accuracy, motion accuracy, and transmission accuracy belong to static accuracy

Geometric accuracy refers to the mutual position accuracy between components and the shape accuracy and position of main parts when the machine tool is not running. Accuracy. The geometric accuracy of machine tools has an important impact on machining accuracy, and is therefore the main indicator for evaluating machine tool accuracy.

Motion accuracy refers to the geometric position accuracy of the main components of the machine tool when it is running at working speed. The greater the change in geometric position, the lower the motion accuracy.

Transmission accuracy refers to the coordination and uniformity of movement between the end-effectors of the machine tool transmission chain.

(2) The above three accuracy indicators are tested under no-load conditions. In order to fully reflect the performance of the machine tool, the machine tool must have a certain dynamic accuracy and the shape of the main parts under the action of temperature rise. , position accuracy. The main factors that affect the dynamic accuracy are the stiffness, vibration resistance and thermal deformation of the machine tool.

The stiffness of a machine tool refers to the machine tool's ability to resist deformation under the action of external forces. The greater the stiffness of the machine tool, the higher the dynamic accuracy. The stiffness of the machine tool includes the stiffness of the machine tool components themselves and the contact stiffness between the components. The stiffness of the machine tool component itself mainly depends on the material properties, cross-sectional shape, size, etc. of the component itself. The contact stiffness between components is not only related to the contact material, the geometric size and hardness of the contact surface, but also to the surface roughness, geometric accuracy, processing method, contact surface medium, preload and other factors of the contact surface.

Vibration occurring on machine tools can be divided into forced vibration and self-excited vibration. Self-excited vibration is a continuous vibration generated internally during the cutting process without being interfered by any external force or excitation force. Under the continuous action of the excitation force, the vibration caused by the system is called forced vibration.

The seismic resistance of the machine tool is related to the stiffness, damping characteristics and natural frequency of the machine tool. Due to the different thermal expansion coefficients of various parts of the machine tool, different deformations and relative displacements of various parts of the machine tool are caused. This phenomenon is called thermal deformation of the machine tool. The error caused by thermal deformation can account for up to 70% of the total error.

There is currently no unified standard for the dynamic accuracy of machine tools. A comprehensive evaluation of the dynamic accuracy of machine tools is mainly made indirectly through the accuracy achieved by cutting typical parts.

(3) Classification of machine tools

Metal cutting machine tools can be divided into many types according to different classification methods.

According to the processing method or processing object, it can be divided into lathes, drilling machines, boring machines, grinders, gear processing machine tools, thread processing machine tools, spline processing machine tools, milling machines, planers, slotting machines, broaching machines, special processing machine tools, Sawing machines and marking machines, etc. Each category is divided into several groups according to its structure or processing objects, and each group is divided into several types.

According to the size of the workpiece and the weight of the machine tool, it can be divided into instrument machine tools, small and medium-sized machine tools, large machine tools, heavy machine tools and super heavy machine tools.

According to processing accuracy, it can be divided into ordinary precision machine tools, precision machine tools and high-precision machine tools.

According to the degree of automation, it can be divided into manually operated machine tools, semi-automatic machine tools and automatic machine tools.

According to the automatic control method of machine tools, they can be divided into profiling machine tools, program-controlled machine tools, digital control machine tools, adaptive control machine tools, machining centers and flexible manufacturing systems.

According to the scope of application of machine tools, they can be divided into general, specialized and special-purpose machine tools.

Among the special machine tools, there is an automatic or semi-automatic machine tool that is based on standard universal components and is equipped with a small number of special components designed according to the specific shape or processing technology of the workpiece. It is called a combination machine tool.

For the processing of one or several parts, a series of machine tools are arranged according to the process, and equipped with automatic loading and unloading devices and automatic workpiece transfer devices between machine tools. This group of machine tools is called Automatic production line for cutting processing.

The flexible manufacturing system is composed of a set of digitally controlled machine tools and other automated process equipment. It is controlled by an electronic computer and can automatically process workpieces with different processes, and can adapt to multiple varieties of production.

(4) Composition of machine tools

All types of machine tools usually consist of the following basic parts: supporting parts, which are used to install and support other parts and workpieces, and bear their weight and cutting force, Such as the bed and column, etc.; the speed change mechanism is used to change the speed of the main movement; the feed mechanism is used to change the feed amount; the spindle box is used to install the machine tool spindle; tool holder, tool magazine; control and manipulation system; lubrication system ; Cooling system.

Machine tool attachments include machine tool loading and unloading devices, manipulators, industrial robots and other machine tool attachments, as well as machine tool attachments such as chucks, suction cup spring chucks, vises, rotary tables and indexing heads.

(5) Model compilation of machine tools

The two naming standards of GB/T15375-94 and GB/T15375-2008 need to be compared and studied, and do not confuse

1.GB/T15375-94 "Metal Cutting Machine Tool Model Preparation Method"

Mainly master (1) the code of the machine tool category (2) the code of the machine tool characteristics (3) the code of the main parameters of the machine tool (4) the machine tool model order.

2.GB/T15375-2008 "Metal Cutting Machine Tool Model Preparation Method"

Mainly master (1) the code of the machine tool category (2) the code of the general characteristics of the machine tool (3) the characteristics of the machine tool Representation method of group, department code and main parameters.