China Shenzhen Perfect Precision Product Co., Ltd. company news

In milling. Milling cutters are consumables. In long-term processing and production, milling cutters are easy to blunt, and after a period of time, milling cutters will be scrapped. The service life of milling cutter in milling processing is related to its own durability. Next, we will introduce the durability of milling cutter. The cutting time of a milling cutter with a new edge (or a new edge on an indexable blade) from the beginning of milling to the time when the wear reaches the tool dulling standard is called the durability of the milling cutter. In actual milling, it is time-consuming and inconvenient to measure whether the wear on the milling cutter reaches the wear limit. Therefore, when the same milling cutter is used in batch production or continuous milling, the durability of the milling cutter is generally used to determine the replacement of the milling cutter. 1、 Durability of milling cutter After the materials and milling conditions of the milling cutter and workpiece are determined, the durability of the milling cutter is related to the milling amount. In order to improve the durability of the milling cutter and prolong the service life of the milling cutter, it is necessary to reduce the milling consumption, especially the milling speed, so as to reduce the production efficiency. If you want to increase the milling amount and reduce the durability of the milling cutter, it is bound to increase the time for changing, adjusting and grinding the milling cutter, and the milling cutter loss is also large and uneconomical. Therefore, the durability of milling cutter should have a reasonable value, that is, under the premise of ensuring the processing quality, the cost should be minimized. The durability of milling cutter should generally be determined according to the structure of milling cutter, manufacturing cost, difficulty of loading and unloading and other factors. 2、 Factors affecting the durability of milling cutter 1. Milling parameters: milling speed is the main factor that affects the durability of milling cutter in milling parameters, because increasing milling speed will significantly increase the cutting temperature and accelerate the wear of milling cutter. The second is the feed rate. Increasing the feed rate will reduce the durability of the milling cutter. Milling width and milling depth have little influence. Generally, in practical work, increasing the milling depth and feed rate and appropriately reducing the milling speed can improve the durability of milling cutters and improve production efficiency. 2. Workpiece material: the higher the strength and hardness of the workpiece material, the better the toughness, the smaller the thermal conductivity, the more serious the work hardening and the higher the thermal strength, the easier the milling cutter is to wear and the lower the durability. 3. Geometric parameters of milling cutter: the rake angle and main deflection angle of milling cutter have a significant impact on durability. Properly increasing the rake angle can reduce the milling force and cutting temperature, so as to slow down the wear of milling cutters; Properly reducing the main deflection angle can increase the working length of the main cutting edge, reduce the cutting load on the cutting edge of unit length, and improve the heat dissipation conditions, so as to improve the durability of milling cutters. 4. Milling cutter material: the milling cutter material has good thermal hardness, high hardness and good wear resistance, so the milling cutter has high durability. However, the milling cutter material should have a certain strength and toughness, otherwise it is easy to cause edge collapse and affect the durability. 5. Cutting fluid: reasonable selection and full use of cutting fluid can reduce cutting temperature and friction resistance, slow down the wear speed of milling cutter, and improve the durability of milling cutter.

Tool is the part of machining equipment that directly participates in cutting. Whether the tool selection is appropriate directly affects the machining quality. When selecting cutting tools, it is necessary to comprehensively consider the workpiece materials, cutting tool materials, processing properties and other factors, so as to select the most appropriate cutting tools and achieve the best processing quality and efficiency. General requirements and development direction of cutting tools For the materials used in manufacturing tools, the most basic requirements are their high-temperature hardness and wear resistance. In addition, they also need to have good bending strength, impact toughness and chemical inertia, as well as the processability of machining methods such as cutting, forging and heat treatment. Generally, if the hardness of the material is high, the wear resistance will be high, but the bending strength and impact toughness will decline. When the material has high strength, its impact toughness will be higher. Under normal working conditions, cutting tools will experience the test of high temperature, high pressure and high speed, and face many difficult to machine materials; In some abnormal working environments, corrosive fluid media will be encountered; In addition, in recent years, with the continuous development of processing equipment, the level of automation and the requirements for accuracy are constantly improving, which have put forward new topics for the tool industry. In order to meet the above requirements, the tool industry must continue to develop and innovate, from the application of new tool materials to vapor deposition coating technology, and then to indexable tool structure, all of which are effective means to improve tool performance, and also an important reference for the machining industry to select tools. Tool material classification and functional characteristics Among the cutting tool materials, the most commonly used are high-speed steel and cemented carbide. High speed steel is the most popular tool material because of its high bending strength, impact toughness and good machinability. Cemented carbide is slightly less widely used than high-speed steel. Cubic boron nitride is a new tool material rising in recent years. It is suitable for cutting metal materials such as high hardness hardened steel and hard cast iron; Polycrystalline diamond is suitable for cutting iron free metals, alloys, plastics and glass fiber reinforced plastics; There are also carbon tool steel and alloy tool steel, which are only used to make files, dies, taps and other tools at this stage. Vapor deposition coating technology is an effective means to improve the function and durability of tools. The coated tools can greatly reduce the wear in cutting and significantly prolong the service life of tools. Among them, chemical deposition is often used to coat titanium carbide, titanium nitride, aluminum oxide hard layer or composite hard layer on cemented carbide tools. Physical deposition can be used to coat cemented carbide and high-speed steel tools. Working part of the tool The cutter is composed of working parts and clamping parts. The working part refers to the part of the tool used to generate and process chips, which usually includes the blade, chip breaking or chip curling groove, chip removal or chip holding space, cutting fluid channel and other structures. Some cutting tools only include the cutting part, whose function is to use the cutting edge to cut chips, such as turning tools, planers, boring tools and milling tools; In addition to the cutting part, some tool working parts also include the calibration part, whose function is to polish the machined surface that has been cut and guide the tool. The working part of the cutter has three different structures, namely, integral type, welding type and mechanical clamping type. The overall structure is to make cutting edges on the tool body; The welding structure is to braze the blade to the steel cutter body; The mechanical clamping structure clamps the brazed cutter head of the blade on the cutter body. Clamping part of tool The clamping part of the tool has two different structural types, namely, with holes and with handles. The tool with hole is sleeved on the spindle or spindle of the machine tool by means of the inner hole, and the torsional torque can be transmitted by means of the axial key or the end key. Cylindrical milling cutter and sleeve face milling cutter all belong to this type. The shape of the handle of a tool with a handle usually includes rectangle, cylinder and cone. The cutting tool used in turning and planing is generally rectangular handle; Conical handle bears axial thrust by its taper and transmits torque by means of friction; In most cases, cylindrical shanks are used in smaller tools such as fried dough twist drills and end mills to transmit torsional torque with the help of the friction generated during clamping. Many tool shanks with shanks are made of low alloy steel, while the working part is made of high-speed steel. The two parts are butt welded to form a defective knife.

With the development of Industrial Science and technology, the application of CNC processing has become more and more extensive, and because the products processed by CNC have high quality and good precision, they have become one of the main processing methods of various parts and components, and have been favored by many. Although this processing method has become the mainstream, it has become a difficult problem for manufacturers to choose CNC processing plants. So, how to solve this problem? Let the hook net tell you which CNC processing company is better. How to choose a CNC processing plant? Although there are high requirements for equipment for CNC processing, the choice of CNC processing plant cannot only depend on its equipment and scale. A decision should be made after a comprehensive consideration of the CNC processing plant according to its own product situation. 1. Standardized operation process The operation process is the basis of ensuring product quality. When choosing a CNC processing plant, you must have a certain understanding of the operation process of the CNC plant. Know more details, such as: whether the safety boot check, boot reset and boot warm-up are completed as required before boot; Whether the determination of die number, workpiece number, reference angle orientation, XYZ three-axis retrieval method and retrieval surface in the program sheet is reasonable; Before the workpiece is put on the machine, the clamping and cleaning, the fastening of screws, and the inspection of workpiece correction; Recheck tools and safety inspection at the beginning of processing, as well as processing data inspection; Whether the relevant processing operation processes such as workpiece cleaning before getting off the machine are standardized and whether there are clear regulations. 2. Implementation of conventional processing standards For processing standards, as long as it is engaged in mechanical processing enterprises, should pay attention to this. The processing standard is the accuracy guarantee after the product is made. Only by meeting the standard can we produce qualified products. Conventional processing standards, such as: whether the processing requirements of the structural assembly groove on the mold kernel are the same as those of the mold embryo; In the process of processing and electrical discharge, Buddha takes data according to the engineering part drawing; Whether the light knife allowance of parting surface can not exceed 0.05mm/s for small molds and 0.08mm/s for large molds, etc. 3. Quality of workpiece delivery The delivery quality of workpieces is the most intuitive way to reflect the strength of CNC processing plants. Considering the delivery quality of workpieces, we can understand the enterprises that have cooperated with the CNC processing factory before. Ask them whether the surface quality and size of the workpiece they receive are the same as those in the drawing, etc. Which one is better for CNC processing? A good CNC processing plant not only has a strong production team, but also has good service quality. Service includes two aspects, one is value-added service, and the other is after-sales service. Value added service refers to regular reporting in product production and handling after production. After sales service is the ability to solve problems after using the product for a period of time. Therefore, when choosing a CNC processing plant, we must consider many aspects, choose a processing plant suitable for our own products, and save costs and improve benefits on the premise of ensuring the quality of products.

High speed grinding belongs to the current manufacturing method in machining technology. Compared with ordinary grinding, it has great advantages. It not only increases the grinding speed, but also improves the production efficiency. The combination of finish machining can better achieve the metal grinding rate comparable to other cutting processes. So, what are the grinding methods for machining? 1、 Ultra high speed grinding Grinding with a grinding speed of more than 150m/s is called ultra-high speed grinding. Ultra high speed grinding can greatly improve the grinding efficiency, prolong the service life of the grinding wheel and reduce the roughness value of the machined surface. It can realize the ductile domain grinding of hard and brittle materials, and also has a good effect on high plasticity and difficult to grind materials. On the ultra-high speed cylindrical grinder, the blank can be directly ground into a crankshaft, and 2kg metal can be removed per minute. At ordinary grinding speed, the grinding force increases rapidly with the increase of grinding rate when grinding nickel base superalloy. Due to the limitation of grinding wheel wear and thermal damage, nickel base alloy can only be ground under the condition of low grinding rate. However, at a grinding speed greater than 140m/s, the grinding force increases little with the increase of grinding rate, so the feed speed can be increased by 60 times (the feed speed of ordinary grinding is not more than 1m/s), and the grinding rate is greatly improved without thermal damage. Foreign countries have developed ultra-high speed grinding wheels with a grinding speed of 500m/s in the laboratory. The grinding speed of ceramic bonded CBN wheel can reach 160m / s. Diamond rollers can be used for shaping grinding, and the grinding surface accuracy can reach ± 0.005mm; The steel wheel body is electroplated with CBN grinding wheel, and the grinding speed is 80-200m/s; The material removal rate of single-layer high-temperature brazed CBN grinding wheel is higher than that of electroplated CBN grinding wheel. The grinding wheel has small wear and long service life, and the grinding speed can reach more than 300m / s; Cast iron based diamond micro powder grinding wheel, which can be shaped by electrolytic on-line dressing method, is suitable for ultra-high speed precision grinding of hard and brittle non-metallic materials such as glass and ceramics. 2、 High speed point grinding High speed point grinding is to form a small inclination angle between the axis of the grinding wheel and the axis of the workpiece in the horizontal plane, so that the grinding wheel and the workpiece become point contact in theory, which not only reduces the area of the grinding contact area, but also eliminates the grinding closed area, which is conducive to the injection of grinding fluid into the grinding area. Because the grinding contact area is small, the cutting force is also reduced, which reduces the possibility of grinding vibration and makes grinding more stable. The loss of grinding efficiency in high-speed point grinding due to the reduction of grinding contact area is compensated by the increased grinding speed. Improving the grinding speed can make full use of the high hardness and high wear resistance of superhard abrasive. At present, the grinding speed in use has reached 120-180m / s. As the grinding speed increases, the cutting thickness of each abrasive grain decreases, which reduces the load on the abrasive grain, is conducive to chip removal, and improves the service life of the grinding wheel. Due to the great improvement of grinding speed, a large amount of heat during grinding cannot be transmitted to the grinding wheel and workpiece and is taken away by chips. It is a kind of cold grinding, which improves the surface quality of machined parts. High speed point grinding also reduces the thickness of the grinding wheel due to the reduction of the grinding contact area, which reduces the price of the grinding wheel and the cost of wheel dressing. Thinning the thickness of the grinding wheel reduces the weight of the grinding wheel, and is also conducive to the uniformity of the quality of the grinding wheel and the balance of the grinding wheel.

Machining center is a NC machining equipment with tool magazine and automatic tool change function. A large number of machining tools and auxiliary tools are stored in the tool magazine, so that the machining center can call when performing different machining tasks. The capacity, structure and layout of the tool magazine play an important role in the design and function of the machining center. The larger the magazine capacity, the better When many enterprise bosses choose machining centers, they think that the larger the tool magazine is, the more complete the tools are, the better. In fact, it is not true, because most processing does not use too many tools. For example, drilling processing can complete 70% of the drilling processing with only 10 cutters; For milling, only 4 cutters are needed to complete 90% of milling. Therefore, usually, 14 cutters can complete more than 60% of the drilling and milling processing. If we consider some special processing, we need special tools. Even so, a total of 40 tools can complete more than 80% of the processing. However, the process of processing orders that most enterprises take over daily will generally not exceed this 80%. Therefore, in most cases, the capacity of tool magazine will be 10 to 40, which can meet most or even all of the processing needs of general small and medium-sized enterprises. Blindly selecting and purchasing equipment with large tool magazine capacity will not only increase the purchase cost, but also occupy a lot of space and area, reduce the tool utilization rate, increase the complexity of the structure of the machining center, and cause a lot of unnecessary waste. The form of tool magazine can be divided into linear tool magazine, disc tool magazine, chain tool magazine and other tool magazines according to different capacities and tool taking methods. The simplest tool magazine - linear tool magazine The cutters are arranged in a straight line in the magazine. Such a magazine has the simplest structure and the smallest capacity. Generally, it can only accommodate 8 to 12 cutters. Linear tool magazine is often used in automatic tool changing CNC lathes. In addition, it has also been used in CNC drilling machines. Because the capacity is too small, this form has been rarely used at present. Disc magazine, the most complex tool magazine in classification The layout of the tools in the disc magazine can be radial layout, axial layout, layout at a certain angle with the axis line of the magazine, or multi circle, multi-layer and multi row layout. The radial layout will occupy a large space, and the position of the tool magazine is limited. This layout is generally placed on the upper end of the machine tool column, which has the advantages of short tool change time and simple structure of the whole tool change device. At present, axial layout is widely used. This layout is often placed on the side of the spindle, and the axis line of the magazine can be placed vertically or horizontally. The tool forms a certain angle with the axis line of the tool magazine, and the secondary angle is less than 90 degrees. This layout is umbrella shaped. The position of the tool magazine is relatively flexible, and there is no rigid arrangement. The tool magazine can be placed according to the overall layout requirements of the machine tool. However, in most cases, this kind of magazine is placed obliquely on the upper end of the column, so the capacity of the magazine should not be too large. The layout of the above three disc tool magazine is commonly used, and the number of stored tools can reach 60 at most. If you want to further expand the capacity, you can use multi circle, multi-layer or multi row layout. The most widely used tool magazine chain tool magazine The tool magazine fixed on the ring link is called chain tool magazine, specifically, there are single row chain tool magazine and folding chain tool magazine. The latter can use extended chains to achieve greater tool storage. The chain type tool magazine is characterized by compact structure, high space utilization, large tool storage capacity, and the shape of the chain link can be adjusted according to the structure of the machining center, so the layout is relatively flexible. Therefore, the chain tool magazine is widely used in machining centers. When the number of props reaches 30 to 120, the tool magazine with this structure is usually used. Other magazine In addition to the above three common tool magazine forms, there are many other tool magazines, including single-sided and multi-sided lattice box tool magazines. The layout of the single-sided lattice box type magazine is extremely inflexible, requiring the magazine to be placed on the workbench. This layout is rarely used now. Relatively speaking, the multi-faceted lattice box tool magazine has a more compact structure and faster tool change speed, but the action of tool selection and tool change is too complex, and it is not often used in single machine machining centers. It is mostly used in the centralized tool supply system of flexible manufacturing systems.

Creep feed grinding is a kind of strong grinding, also known as deep creep feed grinding or creep grinding. The grinding workpiece can be ground to the required size and shape accuracy after one or several strokes. Creep feed grinding is suitable for grinding the surfaces and grooves of high hardness and high toughness materials, such as heat-resistant alloy steel, stainless steel, high-speed steel, etc. Now let's introduce the creep feed grinding process in detail. Creep feed grinding process 1. The grinding depth is large. The contact arc length between the grinding wheel and the workpiece is long, and the metal removal rate is high. Rough grinding and fine grinding are completed in one process, and the production efficiency is 3-5 times higher than that of ordinary grinding. 2. The wear of grinding wheel is small. Because the feed speed is very low, the thickness of debris is thin, and the grinding force borne by a single abrasive is small, the abrasive is not easy to wear, break and fall off; Secondly, the number of reciprocating strokes of the workbench is less, the feed is slow, and the number of collisions between the grinding wheel and the workpiece is less, which reduces the impact between the grinding wheel and the edge of the workpiece, so that the grinding wheel can maintain accuracy for a long time. 3. Due to the small grinding force borne by a single abrasive, the grinding accuracy is high and the surface roughness is low. At the same time, due to the good shape retention of the grinding wheel, the machining accuracy is relatively stable. In addition, the contact arc length can attenuate the grinding vibration, reduce the chatter, reduce the surface waviness and surface stress of the workpiece, and it is not easy to produce grinding cracks. 4. Good economic benefits. Because of the large cutting depth, the grinding is hardly affected by the defects on the workpiece surface, such as oxide skin, white layer of castings, etc. the blanks of precision casting or precision forging can be directly ground to form, reducing machining procedures, reducing blank machining allowance and man hours, shortening production cycle and reducing production costs. 5. The equipment cost is high. The creep feed grinder must increase the power and rigidity of the grinder, and has a creep feed and speed change system, automatic grinding wheel dressing and automatic compensation devices, as well as a strong cooling system. Therefore, the grinder has complex structure, high accuracy requirements, and the equipment cost is much higher than that of ordinary grinders. 6. The large contact surface increases the grinding heat, and the contact arc length makes it difficult for the grinding fluid to enter the grinding area, and the workpiece surface is easy to burn, so a strong cooling system should be equipped. 2、 Requirements of creep feed grinding for machine tools 1. Grinding power: creep feed grinding is efficient grinding, which is mostly used for form grinding. Therefore, the power of the wheel drive motor is required to be large enough, generally more than 18kw. 2. Feeding movement of workbench: when the workbench is slowly fed, it is required to be stable without crawling at the feeding speed of 20mm/min. Generally, hydraulic transmission is not adopted, but mechanical transmission is adopted. At present, screw pairs or ball screw pairs are mostly used to ensure that the machine tool has high transmission stiffness. There should also be stepless speed regulation and quick return mechanism. 3. Rigidity of machine tool: the rigidity of process system is one of the reasons for workpiece processing error. Creep feed grinding requires high dynamic and static stiffness of machine tools. In order to improve the static stiffness of the system, the double-layer reinforced wall structure can be used on the main components such as the front and rear bed, column and carriage; Increase the diameter of the main shaft; The side guide surface of the grinding head vertical movement guide rail and the column carriage horizontal movement adopts the preloaded roller guide rail structure to eliminate the guide rail gap and improve the contact stiffness. 4. Spindle system accuracy: due to the high power of creep feed grinding spindle and form grinding, the spindle is required to be rigid, and axial or radial movement is not allowed. 5. Cooling and flushing: there are two special problems in creep feed grinding: one is that the grinding debris is thin and long, which is easy to block and adhere to the surface of the grinding wheel; Second, the grinding force borne by a single abrasive grain is small, and the self sharpening of the grinding wheel is poor, which is easy to burn the surface of the workpiece. Therefore, it is required to strengthen the cooling and flushing effect of grinding fluid. In order to ensure the cooling and flushing effect, the grinding fluid should be kept clean, and the grinding fluid tank must have a reliable filtration system. The cooling effect is also related to the grinding direction. The cooling condition is good during the forward grinding, the grinding fluid can be brought into the grinding area smoothly, and the cooling effect is good; During reverse grinding, the grinding fluid is not easy to enter the grinding area, and the cooling effect is poor. In addition, during forward grinding, the threshing of the grinding wheel can only fall on the ground surface, which will not scratch the machined surface when washed away by the grinding fluid.

Low Roughness Grinding includes precision grinding, ultra precision grinding and mirror grinding, which can obtain workpiece shape, position and dimensional accuracy with high machining surface roughness. Compared with manual grinding, it has high productivity, easy to realize automatic measurement, and a wide range of processing. However, this processing technology is also relatively demanding for machine tools. The key problems of low roughness precision grinding depend on the selection and dressing of grinding wheels, the selection of grinding parameters and the accuracy and requirements of machine tools. On the special high-precision grinding machine, it can generally meet the grinding requirements, while the general m1432, M131 and other ordinary grinding machines can be used as long as they can ensure the spindle accuracy, the workbench has no jitter, and there is no creeping phenomenon at slow speed. Otherwise, ordinary machine tools must be adjusted and refitted to meet the requirements of low roughness grinding.  Geometric accuracy of grinding machine 1. Rotation accuracy of grinding wheel spindle The rotation accuracy of the grinding wheel spindle is required to be high, and the radial runout and axial displacement of the spindle during rotation shall not be greater than 0.001mm. The following measures can be taken: (1) Improve the machining accuracy of the spindle itself. The spindle accuracy has a direct impact on the rotation accuracy. Therefore, the spindle should be ultra precision ground to improve the spindle accuracy. (2) Choose a reasonable bearing. Common bearings include short three pad or long three pad oil film bearings, integral multi oil wedge sliding bearings and hydrostatic bearings. The above bearings can meet the requirements of low roughness grinding. When using sliding bearings, the clearance must be adjusted to 0.01-0.015mm. Hydrostatic bearings can obtain high spindle rotation accuracy, and their circular runout should be less than 0.05mm. With three short new bearing shells, the rotation accuracy can reach about 0.001mm under the conditions of small clearance (0.005-0.01mm) and small load. It is important to adjust the clearance properly. The clearance is small, and the runout of the main shaft is small, but the clearance is too small, which may cause bearing block phenomenon. 2. Geometric accuracy of workbench Among them, the straightness and parallelism of the longitudinal guide rail of the bed, the straightness of the transverse guide rail of the bed, the parallelism between the center line of the head and tailstock and the moving direction of the workbench, and the parallelism between the center line of the grinding wheel spindle and the moving direction of the workbench should all meet the factory technical requirements of ordinary precision grinding machines. For example, the accuracy of the traverse mechanism is not high, and it is difficult to control the micro feed when dressing the grinding wheel, which cannot meet the high requirements such as micro blade. During grinding, the workpiece will be burned due to too large transverse feed, or the grinding pressure between the grinding wheel and the workpiece will be small due to too small transverse feed, which will not achieve the effect of friction polishing. 2、 Stability of worktable at low speed Low speed dressing grinding wheel is used for low roughness grinding. It is required that there is no crawling and impact phenomenon when the workbench is at low speed (10mm/min). The reasons for creeping are the poor rigidity of the drive system, large friction resistance and large changes in friction. Therefore, to eliminate creeping, the following measures can be taken. 1. Exhaust. If air is mixed in the oil circuit of the hydraulic system, an air release valve can be added to the hydraulic cylinder of the workbench to remove the air. 2. Improve the lubrication effect of guide rail. The guide rail of the workbench is generally lubricated by pressure. If the lubricating oil pressure is too high or the oil quantity is too much, the workbench will float when moving. Avoiding floating can change the structure of the oil groove on the guide rail surface, so that the oil groove is connected with the atmosphere, or add a three-way valve in each of the two guide rail lubrication pipelines of the workbench to return the lubricating oil to the oil pool, so that the guide rail of the workbench can realize pressureless oil supply lubrication. 3. The oil pressure fluctuation should be small. When the gear pump is used in the hydraulic system, its instantaneous flow is uneven, which causes oil pressure pulsation. Vane pump or screw pump can be used instead of gear pump. 4. The reversing of the workbench should be stable. The oil pressure fluctuation will be caused when the worktable is reversed, especially for the machine tool with quick jump action when the worktable is reversed, there is hydraulic shock during the quick jump, so the quick jump reversing should be cancelled. 3、 Reduce machine tool vibration 1. Static balance grinding wheel. Generally, two static balances are required. If possible, dynamic balancing or automatic grinding wheel balancing device can be used. 2. Eliminate motor vibration. The vibration of the grinding wheel frame motor will be directly transmitted to the grinding wheel, which has the greatest impact on grinding.

Plasma cutting technology, with its high efficiency in cutting metal plates and excellent performance in cutting large thickness non carbon steel metal plates, has been widely welcomed by metal processing enterprises since its inception for more than half a century. Since this technology was introduced into China, its popularity has also increased rapidly. With the continuous progress of this technology in recent decades, its final development trend is gradually clear, and will develop towards refinement, intelligence and standardization. High precision, laser like plasma cutting power supply The concept of "fine plasma" was formed in the early 1990s. In order to improve the cutting quality of plasma equipment, cutting power supply manufacturers have increased investment in design and research, and strive to produce isoionic cutting power supply with higher precision, which can be comparable to laser cutting equipment. Through practice, it is found that reducing the size of nozzle hole can produce extremely compressed arc, which greatly improves the current density and energy density of plasma arc, and increases the cutting depth and accuracy of plasma cutting. In this field, some manufacturers from Germany, the United States and Japan have taken the lead. For example, the Kelby series laser plasma cutting machines in Germany have the advantages of narrow incision, smooth cutting surface, no slag hanging, and no need for secondary treatment. They are mainly used in precision cutting and high-speed, low-cost cutting. In addition, Haibao HPR series high-precision plasma cutting power supply system from the United States has occupied the mainstream position in the domestic market with its Hydefinition high-precision technology, longlife long-life technology and true hole fine round hole technology. Hydefinition high precision technology is of great help to improve cutting accuracy; Longlife long-life technology, which precisely controls the rise and decline of current and air pressure, can significantly reduce the wear of electrodes and nozzles, so as to ensure that the equipment can obtain efficient, fine and stable cutting quality for a long time; Rue hole fine round hole technology is a unique patented technology in this series, which can basically eliminate the taper of cutting hole shape. Intelligent plasma cutting power supply With the rapid development of information technology, digital control technology, modern industrial automation control technology and artificial intelligence technology, welding processing has made progress from the era of automation to the era of intelligence. In this regard, some Japanese enterprises have set a good example. Panasonic of Japan has launched the PF3 series plasma cutting machine with full digital control. This is a set of cutting tools that can be called "versatile". Its power supply is equipped with the "unified" navigation function of cutting, which can automatically determine the appropriate cutting parameters according to the material, thickness and other conditions of the processed plate, so as to achieve high-quality cutting. The equipment adopts DSP advanced digital signal processing technology, which can detect the life of vulnerable parts in real time, and will automatically prompt when it needs to be replaced. Standardized integrated plasma cutting technology Through standardized, integrated and modular plasma cutting technology, it is conducive to establish a general technical standard in the industry. Under the constraint of this standard, the cost of purchasing and following up new equipment can be greatly reduced, and the installation, operation and maintenance of equipment and the training of personnel in relevant positions by technicians can be carried out in a more standardized and orderly manner. At present, Issa from Sweden and Victor from the United States are committed to promoting standardized, integrated and modular plasma cutting equipment, so that the power supply and cutting torque between the equipment can be replaced with each other, making it easier to expand and upgrade.

Among the new materials widely used at present, such as various engineering ceramics, optical glass, monocrystalline silicon, etc., they are mostly hard and brittle materials, which are difficult to meet the requirements with general cutting methods. At present, mirror grinding method can be used to meet the requirements of precision mirror grinding. Then, how to grind the mirror of hard and brittle materials? 1、 Grinding mechanism Hard and brittle materials are characterized by high hardness, poor toughness and plasticity, and small fracture toughness. During cutting, chips are mainly generated in the process of crack propagation fragmentation, and the material is removed in a brittle fracture way. Therefore, the machined surface quality is poor. Mirror grinding of hard and brittle materials is mainly carried out by plastic grinding, and the chips are removed by plastic shearing. Experiments show that as long as a very small unit of chip is removed, the energy required to produce plastic deformation is less than that required for brittle fracture. The material is removed by plastic shear rather than brittle fracture. The key is to stably achieve a small enough removal unit cutting, which can achieve crack free, high-quality mirror grinding, and the surface roughness can reach 0.003-0.008 microns. 2、 Requirements for grinding wheel The cutting edge of the grinding wheel should be extremely small, equal height and sharp to achieve fine chip removal. The grinding wheel should have the ability to keep sharp in the grinding process to ensure the stability of the cutting process. For this reason, ultra-fine ultra hard abrasive (diamond or CBN) wheels are used for precision mirror grinding. Compared with ordinary grinding wheel, its characteristics are as follows: (1) The sharp angle of the abrasive tip is small, and the tip is sharp. When the cutting depth is reduced, the cutting layer can be cut off through small deformation. (2) The micro edge of the grinding wheel has good contour, and the actual cutting depth of the abrasive particles is very small. It is in micro cutting, and the grooves formed are very shallow, so the surface roughness can be reduced. (3) The micro blade is very small higher than the binder, and the chip space is often insufficient, and the grinding wheel is easy to be blocked. (4) The fixed area of abrasive particles in the bond is small, the holding capacity of abrasive particles is low, and the abrasive particles are easy to fall off. Therefore, the emergence of metal bond, especially cast iron bond, greatly improves the holding capacity of superhard micro powder abrasive, makes the abrasive particles not easy to fall off, and improves the utilization rate of superhard abrasive wheel. 3、 Dressing grinding wheel by on-line electrolysis method The use of metal bonded superhard abrasive wheels is more likely to cause blockage and make the dressing of the wheels difficult. In the 1980s, someone began to use online electrolysis to repair the grinding wheel. That is, in the grinding process, electrolysis is used to remove a small amount of metal bond on the surface of the grinding wheel, but it has no effect on the abrasive, so that the sharp grinding edge is gradually exposed, and at the same time, chip space is formed. During grinding, the grinding fluid is used as the electrolyte at the same time, the cast iron based grinding wheel is used as the anode (the brush contacts the grinding wheel), and the electrode is used as the cathode. Under the action of electrolytic current, the grinding wheel is corroded, making the abrasive particles exposed to the surface of the grinding wheel. At the same time, an oxide passivation film is formed on the surface of the grinding wheel to prevent further excessive electrolysis on the surface of the grinding wheel. When the abrasive particles begin to blunt during grinding, the passive film begins to be destroyed, and the electrolysis continues, so the grinding edge always maintains the cutting effect. The passivation film can also prevent the cast iron bond from scratching the surface of the workpiece, and the passivation film has a certain friction and polishing effect, which can effectively improve the quality of the machined surface. 4、 Requirements of mirror grinding of hard and brittle materials on machine tools The requirements for machine tools are the same as those for ordinary mirror grinding. But it is more emphasized that the machine tool spindle has extremely high dynamic stiffness, and the axial and radial runout is less than 0.001 micron; The feeding system has good rigidity, smooth and no creep; The spindle grinding wheel system requires precise balance and no vibration; After the grinding wheel is balanced, it should be trimmed and reshaped with high precision; To ensure that the rotation deviation is not greater than 0.001 mm.

Laser cutting is a process that uses high-power and high-density laser beam to irradiate the surface of the cut material, so that the material can rise rapidly until vaporization. A stationary laser beam can form holes on the surface of the material being cut, while a moving laser beam can form a slit with a very narrow width. This is a cutting method with extremely high precision. Laser cutting of metal materials The biggest problem of laser cutting of metal materials is the low absorption rate of energy. Because solid metals have high reflectivity to infrared at room temperature, the commonly used carbon dioxide lasers emit far-infrared laser beams with a wavelength of 10.6 microns, and their energy absorption is only between 0.5% and 10%. However, if the laser energy density can be increased and the metal can be melted quickly in a short time, the absorption rate of laser energy by molten metal will be greatly improved. If you want to melt the metal in a delicate amount of time, the energy density of the laser must reach at least 106 watts per square centimeter. When cutting carbon steel materials, the maximum thickness that the laser cutting system can cut can reach 20mm. When using the oxidation melting cutting mechanism, the width of the cutting seam can be controlled within an ideal range. For carbon steel sheet, the cutting seam can be narrowed to about 0.1mm. For stainless steel and alloy steel, laser cutting is a very effective tool, especially for the manufacturing industry using stainless steel sheet as the main component. Most alloy structural steels and alloy tool steels can also be cut by laser to obtain good edge cutting quality. Only for tungsten containing high-speed tool steel and hot die steel, when laser cutting is used, melting corrosion and slag sticking will occur, resulting in poor cutting quality. Aluminum and alloy: aluminum cutting belongs to the melting cutting mechanism, and the auxiliary gas used is mainly used to blow away the molten products from the cutting area, which can usually obtain better cutting quality. For some aluminum alloys, attention should be paid to prevent the occurrence of intergranular microcracks on the slit surface. Brass plates with small thickness can be cut by high-power laser, and air or oxygen is used as auxiliary gas in the cutting process. But pure copper can hardly be cut with carbon dioxide laser, because this material has too high laser reflectivity. Pure titanium can well couple the heat energy converted by the focused laser beam. If oxygen is used as the auxiliary gas, a very intense reaction will occur. Although the cutting speed is fast, it is easy to form an oxide layer at the cutting edge, and it will cause overburning if you are not careful. Therefore, in order to be safe, it is best to use air as auxiliary gas, so that a good balance can be found between cutting speed and cutting quality. Nickel based alloys, also known as superalloys, have many varieties, most of which can be oxidized and melted by laser. Laser cutting of non-metallic materials The nonmetallic materials mentioned here are mainly divided into organic materials, inorganic materials and composite materials. No matter what kind of non-metallic material, its absorption rate of laser ability is still very good, and the poor thermal conductivity and low evaporation temperature make almost all the absorbed light beams input into the material, and vaporize instantly at the spot irradiation, forming initial holes, thus entering the virtuous cycle of the cutting process. Organic materials that can be cut by laser include plastics and their polymers, rubber, wood, paper products, leather, etc; Inorganic materials suitable for laser cutting include quartz, glass, ceramics and stone; The composite suitable for laser cutting is a new type of lightweight reinforced fiber polymer composite. It is worth mentioning that in the end, this kind of material is difficult to be processed by conventional methods, but the characteristics of non-contact processing with laser cutting can cut, trim and scale the laminated sheet before curing at high speed. Under the heating of laser beam, the edges of the sheet are fused, avoiding the generation of fiber chips.