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

7: Universal tool shank with 24 taper There are usually five different standards and specifications for universal tool holders with a taper of 7:24, namely, NT, DIN 69871, IS0 7388 / 1, masbt and ANSI / ASME. At present, the most commonly used handle models in China are DIN 69871 and masbt. The German standard of NT type tool holder is di2080 and the international standard is ISO 2583. It is characterized by the need to manually mount the tool. On the traditional machine tool, the tool holder is tensioned by the pull rod, and the tool cannot be loaded by the manipulator of the machine tool. While the other four types are used to tighten the tool shank by the pull pin at the end of the tool shank on the machining center. Din 69871 is divided into two types, namely DIN 69871a / AD and DIN 69871 B. the former has the function of central internal cooling, while the latter has the function of flange internal cooling. There is no difference in other aspects. The mounting dimension of ISO 7388 / 1 tool holder is the same as that of DIN 69871, but the D4 value of the former is smaller than that of the latter. Therefore, ISO 7388 / 1 tool holder has the best versatility and can be installed on DIN 69871 taper hole machine tool. However, if the din 69871 tool holder is installed on the ISO 7388 / 1 taper hole machine tool, interference may occur. Masbt is a Japanese standard, and its installation size is completely different from the first three, so it cannot be replaced. This type of tool holder adopts symmetrical structure, which makes it have higher high-speed stability compared with other three types of tool holders. ANSI b5.50 complies with the American Standard. Although its installation dimension is similar to DIN 69871 and IS0 7388 / 1, it cannot be installed on these two kinds of machine tools due to the lack of a wedge notch. However, DIN 69871 and IS0 7388 / 1 tool holders can be installed on ANSI b5.50 machine tools. 1: 10 taper HSK vacuum tool holder The German standard for HSK vacuum tool holder with taper of 1:10 is din69873. When it comes into contact with the spindle of the machine tool, not only does the 1:10 taper of the tool holder contact with the 1:10 taper of the spindle hole, but also the flange surface of the tool holder can be in close contact with the spindle surface by elastic deformation. Compared with the 7:24 tool holder, this double-sided contact system has certain advantages in high-speed machining, connection rigidity and coincidence accuracy. There are six different standards and specifications for HSK vacuum tool holders, namely hsk-a, hsk-b, hsk-c, hsk-d, hsk-e and hsk-f. Among them, hsk-a, hsk-e and hsk-f are most commonly used in the automatic tool changing system of machining centers. The difference between these two types is mainly reflected in two aspects: on the one hand, hsk-a is equipped with a transmission groove, while hsk-e is not. The result of this difference is that the torque transmitted by hsk-a is greater than that of hsk-e, which can undertake some heavy cutting tasks, while the latter can only perform some light cutting. On the other hand, the hsk-a tool handle is also equipped with manual fixing holes, directional grooves, etc., which will have a certain impact on the balance. Hsk-e is more suitable for high-speed machining without these devices. The structures of hsk-e and hsk-f are completely the same. The difference lies in the taper size. That is to say, for hsk-e and hsk-f tool shanks with the same flange diameter, the taper of hsk-f is always one size smaller than that of hsk-e. Therefore, the former main shaft bearing is smaller and the rotation speed will be faster.

In machining, metal mold is one of the most common machining equipment, which is mainly used for metal processing tools. We need to understand the steps in the process of metal molding using metal molds. The steps of mold forming will be described in detail below. Steps of metal mold forming 1. When using metal molds for molding, the CNC punch press strictly punches without plates, and can not empty punch the mold. At the same time, the daily inspection of the mold should also be done well to check the tightness of the locking screw, otherwise the CNC punch and the forming mold will be damaged. 2. The forming direction of the forming die should be upward to avoid the product deformation caused by the collision between the formed shape and the workbench. 3. The closing height and stamping formation of each CNC punch are different. Therefore, it is necessary to adjust the upper part of each set of forming die to the shortest when it is used for the first time. And avoid using it on another punch. In order to avoid damage to the machine tool and the mold, it is necessary to carry out height adjustment before continuing to use. 4. The lower mold of the upward forming mold is usually larger than the standard lower mold ointment. Therefore, in order to avoid indentation of the plate, do not use the punching mold next to it. When the formed mold is not applicable, please remove the oil from the machine tool and store it in the mold cabinet to avoid corrosion and dust. 5. When the mold is fully formed, it needs to adjust the micro distance. During this fine-tuning process, the operator needs to be patient. The common fine-tuning methods mainly include: (1) The stroke of the punch of the numerical control punch cannot be adjusted, only the component height of the die striking head can be adjusted. (2) The stroke of the punch of the CNC punch can be adjusted, and the machine tool can meet the requirements by modifying the parameters during programming. (3) Adjust the height of the die striking head assembly during long-distance adjustment. 6. If it is a high forming or unconventional forming mold, the plate should be well lubricated and double-sided lubricated, so as to strengthen the fluidity of the plate during forming and reduce the chance of plate fracture. 7. The molding die processing program shall be used for programming during molding processing, and sufficient unloading time shall be reserved during programming. The required purpose can be achieved by reducing the punch speed. The punching machine impacts at a low speed, so that the formed material and the mold can be separated for enough time to prevent the deformation of the plate and the deviation of the forming position. 8. The position of plate forming shall be selected reasonably. The clamp and punching parts shall be kept as far away as possible. The plate forming shall be completed at the end of the stamping process as far as possible. 9. Other forming molds can be used around the high forming molds, otherwise the continuous processing of the standard punching die will cause the deformation of the plate. 10. The high forming die has the phenomenon of scratching and collision to the plate, which leads to deformation. Placing balls on both sides of the lower die of the high forming die to assist the transition can avoid this problem.

Main shaft heating and rotation accuracy decrease Fault phenomenon: the main shaft heats up quickly, and the machining produces a lot of noise. The hole accuracy and cylindricity of the processed parts can not meet the requirements. Fault analysis: there may be four reasons for this phenomenon: the first reason may be that the lubricating grease used for the main shaft bearing is unqualified, or the impurities such as dust and moisture are mixed in it, which will reduce the bearing lubrication effect, generate a large amount of heat and noise, and cause the main shaft to heat too fast. The reason why there are impurities mixed into the lubricating grease may be that the machining center did not rectify and dry the compressed air during the pneumatic chip cleaning. The second reason may be that the positioning surface of the tapered hole inside the spindle used to position the tool was damaged during the process of tool drawing and inserting for many times, resulting in the perfect matching between the taper surface of the spindle and the taper surface of the tool shank, and the machined hole had a small eccentric error. The third reason may be that the preload of the front bearing of the main shaft decreases, resulting in a larger clearance of the bearing. The fourth reason may be the fatigue failure of the spring of the automatic clamping device inside the spindle after long-term use, resulting in the tool can not be fully tensioned and deviates from the original position. Treatment method: if the front end bearing of the main shaft is damaged, it needs to be replaced, and qualified lubricating grease must be used, and the bearing clearance must be adjusted to prevent the bearing from being worn again; Install air fine filter and drying device to prevent impurities from mixing into lubricating grease; Grind the positioning surface of the tapered hole in the main shaft and use the color coating method to detect. Ensure that the contact surface between the positioning surface of the tapered hole and the tool shank is not less than 90%; If the clamping device spring fails, it must be replaced and the preload of the bearing shall be adjusted. The pull rod steel ball of the main shaft component is damaged Fault phenomenon: the tail cone surface of the tool shank of the pull rod steel ball tool of the tool automatic clamping mechanism in the spindle is frequently damaged. Fault analysis: through research, it is found that the main reason for this problem is that the tool loosening action of the spindle is not coordinated with the tool pulling action of the manipulator. When the clamping mechanism is not fully loosened, the manipulator performs violent tool pulling, which seriously damages the pull rod steel ball and the tensioning screw. This is because the limit switch is installed at the tail of the booster cylinder. When the piston of the cylinder moves in place, the piston of the booster cylinder cannot be in place in time. Treatment method: clean the oil cylinder and the cylinder, replace the sealing ring and adjust the pressure to make the piston action of the cylinder and the booster cylinder coordinated. In addition, regularly check the gas-liquid booster cylinder to eliminate the potential safety hazard in time. The positioning key of the spindle component is damaged Fault phenomenon: the machining center will make a lot of noise when changing the tool, and the positioning key at the front end of the spindle to rotate the tool handle is partially deformed. Fault analysis: the noise generated during tool change is generated during the tool insertion stage of the manipulator, which is caused by the deviation of the spindle's Quasi stop position and the drift of the reference point for tool change of the spindle. The fixing screws of the orientation detection device of the machining center are easy to loosen after long-term use, which may cause the keyway of the tool handle and the positioning key on the spindle to be misaligned when the manipulator inserts the tool, and the positioning key may be damaged. The drift of the spindle tool changing reference point may be caused by poor contact of the circuit board of the CNC system, changes in electrical parameters, looseness of the proximity switch, etc.

Sheet metal processing is an indispensable metal processing technology in life. From machine tools, automobiles, ships, aerospace to electrical appliances, electronics, communications, medical devices, almost all metal manufacturing industries can not do without sheet metal processing technology. Traditional sheet metal processing needs to consume a large number of molds, resulting in a huge waste of time and material costs. However, with the rise of intelligent processing technology, this situation is expected to be improved. So, what changes can intelligent processing technology bring to the sheet metal industry? Through this article, the reader can learn some information about this, and for the practitioners of sheet metal processing, they can better improve their own equipment and technology. Intelligent manufacturing equipment Traditional sheet metal processing technology relies on plate cutting, blanking and bending equipment. In addition to completing the operation of production and processing, intelligent manufacturing equipment also has the functions of automatic perception, automatic analysis, automatic reasoning, automatic decision-making and automatic control. It is a high integration of advanced manufacturing technology and information technology, computer technology and intelligent technology in equipment products. Intelligent manufacturing equipment reflects the development requirements of intelligent, digital and networked manufacturing industry. Its level has become an important symbol to measure the industrialization level of a country. Intelligent flexible production line Flexible production line is a production line composed of multiple adjustable machine tools, information management system and automatic transportation device. It can combine a variety of production modes, so as to reduce the production cost to the maximum extent and make the best use of everything. Now, under the background of the gradual rise of intelligent technology, the sheet metal processing industry is about to enter the era of flexible production. The establishment of flexible production line based on intelligent technology is the inevitable trend of sheet metal processing. It has incomparable advantages for processing tasks of different varieties, different processes and different batches. With the progress and maturity of technology, the intelligent flexible production line will usher in a high-speed development period. Industrial robot Industrial robot is a machine device that automatically performs processing tasks. It can work under the command of people and run automatically according to the program written in advance. Industrial robots with intelligent technology can even assist or replace people's work according to the set principles and guidelines. At present, the sheet metal processing industry has been applied to robots, only in those processes with poor working conditions, such as blanking, grinding and welding. Now, some enterprises have begun to conduct in-depth research on the use of robots for more processes from design, process to production. In the future, robots will more and more penetrate into all processes of the industry, and truly realize the maximum promotion and application. Information management system The development trend that sheet metal processing will adopt automation and intelligent technology will inevitably promote the reform of sheet metal processing enterprises in management mode. The establishment of information management system is imperative. This system includes a series of management project modules such as logistics management system, production management system, process technology system, quality management system, automatic quotation system, cost management system and safety assurance system. All modules are managed according to the preset requirements, and the production process is effectively controlled in an all-round way without dead angle.

Mechanical manufacturing technology is based on the theoretical knowledge of surface forming, metal cutting and process system, with various processing methods, processing equipment and applications as the main body, and the design of machining process and assembly process as the focus to achieve the production purpose of high-quality and high-efficiency mechanical products. In the mechanical manufacturing technology, the design of the machining process is the focus. Next, we will explain the system to let you know what the content of the machining system is. The machining process system mainly includes five aspects: production process and technological process, production type, machining allowance, benchmark and general principles for drawing up process route. The following will be described item by item: 1、 Production process and technological process The production process is the process of making raw materials into products. The technological process is the process of changing the shape, size and performance of raw materials. 2、 Production type Production types are mainly divided into three categories: single piece production, batch production and mass production. Single piece production: it refers to the production of a single part with little or no repetition. Batch production: the production of the same parts in batches. Mass production: when the manufacturing quantity of a product is large, the production of a certain process of a part is repeated. 3、 Machining allowance Machining allowance is the excess metal part cut from the blank to meet the qualified standard. Machining allowance is divided into process allowance and total allowance. The machining allowance on the workpiece is mainly to remove the machining error and surface defects left by the previous process, so as to improve the accuracy and surface roughness of the workpiece. 4、 Benchmark Mechanical parts are composed of pairs of surfaces. As an indispensable part of machining, datum plays an important role in determining the points, lines and surfaces on the parts. In processing, the reference can be divided into design reference and process reference quantity, 1. Design datum: it is mainly used to determine the position of its point, line and surface. For example, the design datum of each outer circle and inner hole of the shaft sleeve part is the axis line of the part. 2. Process datum: the datum used in the processing and assembly of parts. Process datum is divided into assembly datum, measurement datum and positioning datum. (1) Assembly benchmark: refers to the benchmark of the relative position of components or products used in the assembly process. (2) Measuring datum: it is mainly used to check the dimension and position accuracy of the machined surface. (3) Positioning datum: the datum used for workpiece positioning during machining. 5、 General principles for preparing process route The machining process specification is roughly divided into two steps. The first step is to draw up the process route of parts processing, and then determine the size, equipment, process equipment, cutting specifications, man hour quota, etc. of each process. The general principles of the proposed process route mainly include the following aspects: 1. Datum first - the datum plane is processed first During the processing of parts, the surface of positioning reference needs to be processed first, so as to provide precise reference for the processing of subsequent processes as soon as possible. 2. Divide processing stages For surfaces with high processing quality requirements, the processing stages need to be divided. Generally, they can be divided into three stages: rough processing, semi finishing processing and finishing processing. This is to ensure the processing quality, reasonably use the equipment and facilitate the arrangement of the heat treatment process; And it is convenient to find blank defects. 3. After the hole The principle of machining the hole on the machining plane first is suitable for machining the box, bracket, connecting rod and other parts. In this way, the holes can be processed by plane positioning, ensuring the positional accuracy of the plane and the holes, and bringing convenience to the processing of the holes on the plane. 4. Finishing of main surface It shall be carried out at the last stage of the process route to avoid damage to the finished surface due to transfer and installation between processes.

The quality of the workpiece depends not only on the material of the workpiece, but also on the processing technology. Boring is just like this. The boring processing method has a great influence on the processing quality of the workpiece, especially from the perspective of the movement of the boring machine The formula has a direct influence on the machining accuracy of the hole. （1） Overhanging boring 1. Boring bar feed suspension boring In the boring process, with the feeding of the boring bar, the extension length and deformation of the boring bar will increase. Under the influence of cutting force, the deformation of the boring bar at different processing positions will be different, so the bore diameter will be different. In addition, with the increase of the overhang of the boring bar, the bending caused by the gravity of the boring bar itself also changes. In the whole boring process, the greater the cutting force, the longer the extension length of the boring bar, the greater the deflection of the boring bar, and the axis of the bored hole will be curved, resulting in the roundness error, cylindricity error of the hole and the coaxiality error of the coaxial hole system. Therefore, the boring bar feed suspension boring method is generally suitable for rough machining with low accuracy requirements. 2. Worktable feed suspension boring In this boring processing mode, although the tip of the boring tool also has deflection under the action of cutting force and the gravity of the boring bar, the extension length of the boring bar remains unchanged during the whole boring processing process due to the use of workbench feeding, so this deflection is a constant value. Only when the feeding direction of the workbench is an accurate straight line, the axis of the hole is a straight line. All deviations in the feed direction of the table can cause bending and deflection of the axis of the hole. Therefore, the accuracy of the holes bored by the worktable feed suspension boring method depends on the accuracy of the boring machine itself. Under the condition of good accuracy of the machine tool, the machining accuracy of this machining method is higher than that of the boring bar feed suspension boring method, so it is suitable for precision machining. （2） Support boring method 1. Table feed support boring In the boring of the feed support of the worktable, the spindle rotates and the worktable feeds. In this processing mode, the distance between the two support points is relatively long. Because it is the support boring through which the boring bar penetrates, the straightness error of the hole axis is small, the change of the hole size is small, and only a very small fixed value is uniformly reduced, so this machining method is suitable for finishing machining. 2. Boring bar feed support boring When boring in this way, the extension length of the boring bar is unchanged, and the deflection generated by the cutting force is smaller than the deflection of the worktable feed support boring. It has good vibration resistance and can be processed with a wide edge cutter. However, due to the feeding of the boring bar, the position of the boring tool between the supports is changed. The bending caused by the weight of the boring bar will affect the straightness error of the workpiece hole axis. The deformation of the boring bar caused by the cutting force is smaller than that of the worktable feeding support boring. However, since the bending of the hole axis is not easy to correct, it is better to use the worktable feeding support for boring.

Machining parts and components is one of the important components in mechanical manufacturing. The normal use of parts and components plays a vital role in the work of machinery. Therefore, in order to ensure the accuracy of parts, the surface treatment of machined parts needs more attention. So, what are the types of surface treatment of machined parts? How should we proceed? 1. Sandblasting This kind of processing of machined parts mainly uses electrostatic force or pressure drop, or powder is attached to the surface of the workpiece to effectively prevent corrosion deformation of parts. 2. Baking varnish Add a layer of primer and finish on the base material of the parts. In the process of painting, if there is no layer of paint, it needs to be sent to a dust-free and constant temperature baking room for baking. 3. Electroplating This surface treatment method of machined parts is quite common in production and processing. It mainly uses the function of electrolysis to make metal or other materials add a layer of metal film on the surface of machined parts through electrolysis. This can play an anti-corrosion role, and at the same time, it is very helpful to enhance the hardness and wear resistance, and effectively protect the surface accuracy and quality of machined parts. 4. Anodizing Electrochemical oxidation of metals and alloys. The anode is a metal or alloy component, and its surface is formed into a thin film of oxide by electrolysis. This film can effectively change the surface state and performance of machined parts. For example, common surface coloring, improving corrosion resistance, enhancing wear resistance and hardness, etc. anodic oxidation is very helpful to this. 5. Infiltration This surface treatment is a sealing process of microporous penetration. It is mainly to penetrate the sealed medium into the micropores through natural penetration, vacuum pumping and pressurization, fill the gaps, and then cool or heat them at natural temperature. Once, the sealing medium in the gap is solidified and the gap is sealed. 6. Fuel injection This kind of surface treatment method for machined parts is the simplest. It only needs to spray paint on the surface of the parts, and then it does not need to bake like baking paint. It only needs to dry the sprayed parts naturally. 7. Sandblasting This surface treatment method mainly uses air, compresses the programming power, and then sprays it to the surface of the parts to be treated in the form of jet, so that the surface appearance or shape of the parts will change. Due to the impact force and cutting force of the abrasive on the surface of the workpiece, the surface of the workpiece will also have different cleanliness and roughness, so that the mechanical performance of the workpiece surface can be effectively improved. Therefore, it is very helpful to improve the fatigue resistance of components. Moreover, the adhesion between the coatings and the durability of the coating film can also be extended.

There are many kinds of metal cutting methods, which vary according to the specific requirements and conditions of the processed parts. There are also certain differences in the selection of processing methods. In the process of actual production, the main processing methods of parts often used are turning, drilling, boring, planing, broaching, milling and grinding. Although there are many similarities in the principle of machining, the form of cutting motion is different, so the machine tools and tools used are also very different. Therefore, it has its own process characteristics and application scope. 1. Turning Ordinary machine tools are the most common machine tools for turning workpieces. It mainly relies on the linear movement of the tool and the rotary movement of the part as the feed movement. Turning is the process of cutting metal from a workpiece. While the workpiece rotates, the tool cuts into the workpiece or turns along the workpiece. It is more suitable for machining the rotary surface. The main characteristics of turning are easy to ensure the position accuracy of the workpiece, high production efficiency, low production cost and suitable for a wide range of processing materials. 2. Drilling Drilling is the processing of drilling holes on solid metal, mainly for axial feed movement. The application of drilling is mainly in single piece and small batch production. In batch or mass production, in order to ensure the accuracy of processing, group massage and multi axis cobalt are used to process holes. In addition to drilling, the drilling machine can also perform other processing. When drilling, the workpiece is clamped and fixed; The drill bit rotates while drilling into the workpiece. 3. Boring Boring is a processing method to enlarge or further process the drilled or cast hole on the metal workpiece. Boring mainly refers to the rotation of the boring tool. The boring process is mostly carried out on milling and boring machines and boring machines. 4. Ox head planing, dragon door planing and slotting Planing mainly involves plane processing. It is a common processing method in plane processing of single piece and small batch production. The most common processing methods are ox head planing, dragon door planing and slotting. When machining with a planer, the workpiece is fed to the cutter, and the cutter moves back and forth on the workpiece. The process characteristics of planing mainly include good universality, low production efficiency and low processing accuracy. It is widely used in maintenance workshop and mold workshop. Planing is mainly used for small batch production of single piece. Su ri'an planing is mainly used for plane processing, but it is also helpful for processing straight grooves. 5. Broaching The axial movement of broach under the action of tension. Good performance for machining the inner and outer surfaces of workpieces. Broach has a complex structure, high cost in manufacturing, and there are certain special types, so broaching is mainly used for mass production. Broaching is characterized by high production efficiency, high machining accuracy and simple broaching machine structure. 6. Milling Milling is the process of cutting metal with rotary tools, mainly used for plane processing. The commonly used machine tools are horizontal milling machines or vertical milling machines. It has the technological characteristics of high production efficiency and good heat dissipation of cutter teeth. In single piece and small batch production, the lifting table milling machine is used for processing small and medium workpieces, and the gantry milling machine is used for processing large workpieces. 7. Grinding Grinding is mainly the processing of the working surface. The grinding process is characterized by high grinding accuracy, good processing for some difficult and easy to process materials, and high cutting speed.

Installation items of bearing: 1、 Clean bearing and bearing related parts The bearing and its associated parts need to be cleaned, while the bearing that has been lubricated with grease, the bearing with oil seal on both sides and the bearing with seal ring need not be cleaned before installation. 2、 Check the dimension and finishing of related parts 3、 Installation During the installation of bearings, it is necessary to determine the installation method and installation plan according to the structure, size and matching properties of bearing components. The pressure shall be directly loaded on the end face of the tight fitting ferrule and cannot be transmitted through the rolling element. 1. Press fit This kind of fitting is to make the inner ring of the bearing and the shaft tightly fit. If the outer ring and the bearing are loosely fitted, the press can be used to press fit them on the circumference, and then the pressed whole can be installed into the bearing seat hole. During the press fitting, the position is at the end face of the inner ring of the bearing, which can be padded by the assembly sleeve to avoid being pressed on the cage. The bearing outer ring is tightly fitted with the bearing seat hole. If the inner ring is loosely fitted with the shaft, press the bearing into the bearing seat hole first. If the bearing ring is relatively tight with the shaft and seat hole, install the inner ring and outer ring and press them into the shaft and seat hole at the same time. The structure of the assembly sleeve shall be able to press the end faces of the bearing inner race and outer race at the same time. 2. Heating fit This is mainly the method of using the principle of thermal expansion and cold contraction to install the bearing. This method is very helpful for the installation of bearings with large interference. Before hot assembly, the bearing or the separated circumferential ring shall be put into the oil tank for uniform heating. After heating to a certain degree, take out and install it on the shaft. 3. Installation of tapered hole bearing Press in with a press or install with a general hot assembly method. For the case of taper hole, it can be directly installed on the taper shaft or installed with a sleeve. When the bearing is installed in the housing, the clearance is generally more matched, and the outer ring should have interference. 4. Installation of thrust bearing The fit between the circumference of the thrust bearing and the shaft is generally transition fit, and the fit between the seat ring and the bearing seat hole is generally clearance fit. Therefore, this bearing is easy to install. The central shaft spring of the two-way thrust bearing should be fixed on the shaft to prevent rotation relative to the shaft. 4、 Inspection after installation of bearing After the bearing is installed, it is necessary to check the operation of the bearing to verify whether the installation is correct. 5、 Supply lubricant Before installation, unpack the bearing. General grease lubrication, no cleaning, directly filled with grease. Lubricating oil is used for lubrication, and ordinary bearings do not need to be cleaned. However, bearings used for instruments or high-speed bearings should be cleaned with crystalline oil to remove the rust inhibitor applied on the bearings. The bearing with the rust inhibitor removed is more likely to rust, so it cannot be left unattended. Bearings that have been put into lubricating grease cannot be directly cleaned.

Failure causes and maintenance methods of belt drive 1. Journal bending Causes: the dynamic balance of the pulley is poor, the axial strength is low, and the loading and unloading are improper. Solution: the belt pulley shall be dynamically balanced; Cold straightening of slender shaft and small shaft; The shaft is appropriately thickened. 2. Pulley hole or journal wear Cause: the fit between wheel hole and journal is too loose. Solution: when the wear is not large, boring the wheel hole, chrome plating or spraying the journal to ensure the design requirements; When the wheel hole is seriously worn, the wheel hole can be bored and matched, and the sleeve can be fixed with slotted screws, and the keyway in the sleeve can be reworked. 3. Pulley collapse Cause: the wheel hole and the journal are too tight and cracked, or too loose and impacted. Solution: weld, insert or replace the pulley. 4. Belt slip Cause: the belt tension is insufficient, and the initial speed of the driving wheel is too high. Solution: adjust the tensioning device; Replace the old belt; Add anti-skid agent on the belt surface to increase the friction. 5. Tape skipping or tape dropping Causes: the belt is partially worn and damaged, and the center lines of the two belt wheels are skewed. Solution: replace the new belt; Align the center lines of the two wheel rims.    Damage characteristics and maintenance of chain drive 1. Wear of plate chain assembly This damage is mainly characterized by the plate chain being stretched, shaking during operation, chain dropping or chain jamming. The solution is to adjust the center distance and tighten the chain; Adjust the tensioning wheel and tighten the chain; Remove a section of chain link; In case of serious chain dropping and jamming, it shall be removed and replaced to avoid aggravation of wear. 2. Tooth profile wear The teeth tend to be sharp and thin, and the tooth tip is inclined to the direction of the chain force, which aggravates the wear of the chain. Solution: for moderate wear, the sprocket can be turned over for continued use; Some gear teeth are obviously worn and can be used in transposition; The sprocket with severe wear shall be replaced. 3. Sprocket surface deformation When the sprocket rotates, the teeth are not on the same plane, resulting in chain dropping, chain biting or chain skipping. It can be solved by checking and leveling the sprocket surface on the flat plate. 4. Two wheel offset Chain bite, sprocket and local wear of the chain are intensified. The solution is to check with the pull wire method on site and then adjust the sprocket position. 3、 Maintenance of gear transmission 1. Change gear fatigue wear, pitting and peeling (1) Improper selection of gear material: re selection. (2) Low hardness of gear teeth: heat treatment. (3) Gear overload operation or uneven load distribution: ensure proper side clearance and contact spots. 2. Cracked or broken teeth (1) Impacted or hard objects stuck in the gear teeth: carefully check and manually pull before driving (2) Quenching crack: gear shall be subject to flaw detection 3. Indentation on the tooth surface There are iron scraps and other impurities between the gear teeth during transmission: clean the oil tank and gear. 4. Gear wear during low-speed operation The oil film is too thin: use high viscosity lubricating oil. 5. Gear wear during high-speed operation Overload, poor lubrication or too small side clearance: adjust side clearance, reduce load and improve lubrication. 6. Tooth tip sharpening, tooth root bite, plastic deformation of teeth (1) The center distance is too small and the meshing is poor: use the modified gear. (2) Overload, oil cut-off, overheating, insufficient tooth hardness and strength: reduce the load, timely supply oil, and ensure the hardness and strength of the tooth surface. 7. Gluing (1) Excessive load, gear overload transmission: reduce the load. (2) Poor lubrication: improve lubrication. (3) Rough tooth surface, low hardness and poor contact: improve tooth surface hardness and surface roughness. 8. The small wheel is greatly worn (1) Large difference in the number of teeth: improve the hardness of the small wheel. (2) Rotating speed: improve lubrication conditions.