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

The processing of sheet metal bending parts refers to the processing of changing the angle of the sheet or plate. Such as bending the sheet into V-shape, U-shape, etc. With its light weight, high strength and good performance, sheet metal bent parts are widely used in electronic and electrical, intelligent communication, automotive industry, medical equipment and other fields. Electrical conductivity. However, during the processing of sheet metal bent parts, due to the influence of the mold, bending pressure and other factors, the bent sheets are often affected by indentation or scratches of different degrees, which affect the appearance and quality of the bent parts. So how to avoid this situation? If we want to avoid indentations, we need to find out the reasons for eliminating them. Usually, both of these reasons will lead to indentation marks in the sheet metal bending parts during the process. Firstly, the mold is not cleaned in place, so we need to check whether there is waste on the surface or inside of the mold before the product is formed. Secondly, there is a problem with the structure of the V-slot of the mold. The larger the R angle of the V-groove of the die, the smaller the pressure between the plate and the shoulder of the V-groove of the die, the lighter the indentation, and vice versa.  

In the use of stamping materials, stainless steel materials are mostly used. What should we know in advance about stainless steel stamping? To avoid unnecessary situations? During stainless steel stamping, we need to pay attention to the situation of springback deformation of stainless steel materials. Stainless steel materials will have springback after stretching and forming. Due to the high hardness of stainless steel and the large springback of materials, when designing the molding die, we need to predict the springback value of materials to minimize the size problems caused by material springback. Heat treatment: Many stainless steel stamping and drawing parts have higher hardness requirements, but the harder the material is, the more difficult it is to stretch. Sometimes it is necessary to conduct heat treatment after forming to meet the hardness requirements, but the stamping parts after heat treatment are prone to deformation, so the deformation amount needs to be considered in the mold design. Selection of tools: stainless steel has high hardness, which will cause relatively large loss to the tool edge of the mold. Therefore, proper selection should be made according to the hardness of stainless steel materials when selecting tools. Selection of stainless steel stamping oil. In order to make stamping parts easy to clean, we can choose low viscosity stamping drawing oil. In stainless steel stamping, there may be scratches on the surface, cracks on the stamping parts, and problems with the material on the die.

The metal stretching process shall be combined with the actual situation, and a reasonable process plan shall be selected from the aspects of quality, strength, environment and production, so as to reduce the process investment as much as possible on the basis of ensuring that the production meets the requirements of the drawings. Type and process requirements of metal stretching process: 1、 Type of metal drawing process (1) Cylinder stretching: stretching of cylinder with flange. The flange and the bottom are straight, and the cylinder is axisymmetric. The deformation is uniform on the same circumference, and the blank on the flange has deep drawing deformation. (2) Elliptical stretching: the blank on the flange is stretched and deformed, but the deformation amount and deformation ratio change accordingly. The greater the curvature, the greater the deformation of the part of the blank; The deformation of the part with smaller curvature is smaller. (3) Rectangular stretch: a low rectangular piece formed by one stretch. When stretching, the tensile resistance at the fillet of the flange deformation area is greater than that at the straight edge, and the deformation degree at the fillet is greater than that at the straight edge. (4) Hilly stretching: the side wall is suspended in the process, and it will not stick to the mold until the end of forming. The deformation characteristics of different parts of the side wall are not completely the same during forming. (5) Dune shaped drawing: the blank deformation of the mound shaped cover plate in the forming process is not a simple tensile deformation, but a composite forming in which both tensile and bulging deformation exist. (6) Hemispherical drawing with flange: when the spherical part is stretched, the blank partially contacts the spherical top of the punch, and most of the rest is in a suspended state. (7) Flange stretching: stretch the flange slightly. The stress and strain situation is similar to that of compression flanging. (8) Edge stretching: angle re stretching is carried out for the flange, and the material is required to have good deformation. (9) Deep stretching: it can be completed after more than two times of stretching. The wide flange stretch piece is stretched to the required flange diameter at the first stretch, and the flange diameter remains unchanged at the subsequent stretch. (10) Conical drawing: due to the large degree of deep deformation, the deep conical parts are very easy to cause local excessive thinning and even cracking of the blank, and need to be gradually formed through multiple transitions. (11) Rectangular re drawing: the deformation of high rectangular parts formed by multiple drawing is not only different from that of deep cylindrical parts, but also different from that of low box parts. (12) Curved surface forming: Curved surface stretch forming, which makes the outer flange part of the metal plate blank shrink and the inner flange part extend, becoming a stamping forming method of curved surface shape with non straight wall and non flat bottom. (13) Step stretch: re stretch the initial stretch to form a stepped bottom. The deeper part will deform at the initial stage of stretch forming, and the shallower part will deform at the later stage of stretch forming. (14) Reverse stretching: reverse stretching is a kind of re stretching for the workpieces stretched in the previous process. The reverse stretching method can increase the radial tensile stress, and has a good effect on preventing wrinkling. It is also possible to increase the tensile coefficient of re stretching. (15) Thinning stretching: different from ordinary stretching, thinning stretching mainly changes the thickness of the cylinder wall of the stretching piece during the stretching process. (16) Panel stretching: the surface shape of the panel is complex. In the drawing process, the blank deformation is complex, and its forming property is not simple drawing forming, but the compound forming of deep drawing and bulging. 2、 Scheme of metal drawing process (1) According to the workpiece drawing, analyze the shape characteristics, size, accuracy requirements, raw material size and mechanical properties of the workpiece, and combine the available equipment, batch and other factors. Good drawing process shall ensure less material consumption, fewer processes and less equipment occupied. (2) The calculation of main process parameters is based on the analysis of stamping process, to find out the characteristics and difficulties of the process, and to propose various possible stretching process schemes according to the actual situation, including process nature, process number, process sequence and combination mode. Sometimes there may be multiple feasible process schemes for the same workpiece. Generally, each scheme has its advantages and disadvantages. Comprehensive analysis and comparison shall be carried out to determine the best suitable scheme. (3) Process parameters refer to the data on which the process plan is based, such as various forming coefficients (drawing coefficient, bulging coefficient, etc.), part development dimensions, and various stresses. There are two cases of calculation. The first is that the process parameters can be calculated more accurately, such as the material utilization rate of the part layout, the workpiece area, etc; The second is that the process parameters can only be calculated approximately, such as general bending or deep drawing forming force, blank development size of complex parts, etc. The determination of such process parameters is generally based on the rough calculation of empirical formulas or charts, and some need to be adjusted through tests. (4) The stretching equipment shall be selected according to the nature of the process to be completed and the force and energy characteristics of various equipment, the required deformation force, size and other major factors, and the equipment type and tonnage shall be reasonably selected in combination with the existing equipment. 3、 Selection method of stretching oil (1) As silicon steel plate is a material that is easy to stretch, low viscosity stamping oil will be used to prevent scratches on the premise of easy cleaning of the finished workpiece. (2) When selecting drawing oil for carbon steel plate, the better viscosity should be determined according to the process difficulty and degreasing conditions. (3) Because of the chemical reaction with chlorine additives, it should be noted that chlorine type drawing oil may cause white rust when selecting drawing oil for galvanized steel plate, while sulfur type drawing oil can avoid rust. (4) Stainless steel is easy to harden, so it is required to use drawing oil with high oil film strength and good sintering resistance. Generally, the drawing oil containing sulfur and chlorine compound additives is used to ensure the extreme pressure performance and avoid problems such as burrs and cracks on the workpiece.

Shell stretch stamping is a kind of stamping made by stretch technology. Drawing is to press the flat metal sheet into the die through the movement of the punch. The shell drawing stamping parts are widely used, such as automobile parts, household products, electronic equipment, etc. The shell stretching stamping part can stretch the sheet metal into a cylindrical bottle type part; In the drawing operation, the diameter of the blank is affected by the circumference of the shell, and the circumference is affected by the fluidity of the stamping materials and the inward flow resistance and edge resistance of the peripheral materials; When the resistance of the edge material exceeds the limit, the edge will wrinkle and become unstable. To avoid wrinkling, the stamping material must flow smoothly between the punch and the blank holder. The two main reasons for tensile fracture are: the ratio of the diameter of the drawn stamping part to the diameter of the blank exceeds the limit value, and the stretching radius is drawn from a flat blank to a shell, when the shell is stretched to a shell with a smaller diameter, there is a limit value for the inward flow distance of the material, usually called the stretching coefficient. The ultimate tensile coefficient is affected by such factors as material fluidity, material compression resistance and flow resistance caused by compression. Excessive flow resistance causes the shell edge to be damaged and wrinkled, which is the area with the weakest material resistance.

During the use of stamping die, due to the natural wear of die parts, unreasonable die manufacturing process, improper installation or use of the die on the machine tool, equipment failure and other reasons, the main parts of the die will lose their original performance and accuracy. As a result, the mold technology is deteriorating, affecting the normal production, efficiency and product quality. Therefore, it is necessary to do a good job of maintenance to make the stamping die work better and increase the service life. What kind of daily maintenance do you usually need to pay attention to? There are three stages of daily maintenance that need attention. 1: Preparation before use of stamping die Before installing the mold, the surface of the mold needs to be cleaned and maintained so that the mold mounting surface and the worktable of the press will not be damaged by pressure. It is also necessary to check whether the fastening parts are abnormal. 2: Maintenance of stamping die in use The sliding parts of the mold shall be lubricated regularly to prevent the surface of the sliding parts from being worn due to rough operation. The mold operation status shall be paid attention to at any time, and the machine shall be stopped immediately for maintenance in case of any abnormality. 3: Disassembly of stamping die after use After the mold is used, the mold should be removed from the press according to the correct operating procedures, and it must not be disassembled randomly. After disassembly, it shall be wiped clean and coated with oil for rust prevention.

At present, metal stamping processing is a commonly used metal processing method in China. In the production process of workpieces, due to the comprehensive influence of various factors such as the processing accuracy of machinery and equipment, mold wear, and processing error, it is difficult to achieve absolutely accurate dimensions of metal stamping parts produced and processed. Therefore, in order to ensure the availability of the workpiece, the tolerance of metal stamping parts must be controlled to the minimum. So do you know what the tolerance standards for metal stampings are implemented according to? GB/T13914-2002 Dimensional Tolerance of Stamping Parts specifies the dimensional tolerance of stamping parts. Dimensional tolerances are specified for flat and formed stampings respectively. The dimensional tolerance value of stamping parts is related to the dimensions of stamping parts and plate thickness, on the other hand, it is related to the accuracy level. Dimensional tolerance of flat stamping parts: it is divided into 11 grades, which are represented by ST1 to ST11. Among them, ST represents the dimensional tolerance of flat stamping parts, and the tolerance grade code is represented by Arabic numerals. The accuracy level decreases from ST1 to ST11. Dimensional tolerance of formed stampings: the formed stampings are divided into 10 accuracy grades, which are represented by FT1 to FT10, where FT represents the dimensional tolerance of formed stampings, and Arabic numerals represent the tolerance grade. The accuracy level decreases from FT1 to FT10. Limit deviation of stamping parts: the hole size shall have a press deviation of 0, and the upper deviation shall be the lower deviation plus dimensional tolerance; The upper deviation of shaft size is the basic deviation, the value is 0, and the lower deviation is the upper deviation minus the dimension tolerance. The upper and lower deviations of hole center distance, hole edge distance, length and height of bending and drawing are specified as half of the dimensional tolerance. Tolerance is the range of dimensional changes. The larger the value, the lower the precision, and the less difficult the machining. The smaller the value, the higher the precision, and the greater the machining difficulty.

With the improvement of the current quality of life, metal stamping parts have gone deep into various fields, and it has been closely related to our life. The metal stamping parts are made by stamping process, which is a processing method to obtain workpieces of certain size, shape and performance by applying external force to the work-piece blank through the mold to cause plastic deformation or separation. The stamping and stretching process shall be selected and designed according to the actual conditions of equipment and personnel, with advanced technology, reasonable economy and safe and reliable use. The following describes the technological advantages and manufacturing principles of the metal stamping parts: 1、 Technological Advantages of Metal Stamping Parts (1) The assembly and repair of metal stamping parts require convenience, convenience and energy saving. (2) The shape of the metal stamping parts is simple and the structure is reasonable, which can be conducive to the manufacturing of the mold. (3) Hardware stamping parts shall be used to the maximum extent or to the existing materials, equipment, process equipment and process flow. (4) Metal stamping parts can improve the utilization rate of metal materials and reduce the types and specifications of materials. (5) The metal stamping parts are conducive to the interchangeability of the same batch of workpieces to reduce the scrap situation. 2、 Manufacturing principles of metal stamping parts (1) Precision principle: the number of processes of deep drawing parts is related to material properties, drawing height, number of drawing steps, drawing diameter, material thickness, etc. (2) Fine principle: the number of processes for bending parts mainly depends on the disorder degree of their structural shape, which should be determined according to the number of bending angles and bending direction. (3) Exquisite principle: when the section quality and standard precision of the stamping parts are required to be high, it can be considered to add the finishing process after the blanking process or directly select the fine blanking process. (4) Precision principle: when blanking workpieces with simple shapes, single process die can be used. When blanking workpieces with messy shapes, due to the limitation of the structure or strength of the die, it is summarized in the table that several parts should be divided for blanking, and multiple metal stamping processes should be used. (5) Boutique principle: in order to ensure the quality of fine metal stamping parts, sometimes the number of processes is required. For example, the additional process hole punching of bending parts, the addition of deformation reduction hole punching in the forming process to transfer the deformation area, etc., ensure the degree of fine and exquisite products.

A mold is a tool used to form an object and is composed of several parts. Different molds consist of different parts. Mold maintenance requires qualified mold maintenance workers who have received professional training. In the maintenance process, we must understand the mold technical standards. For example, a die casting mold is a very expensive special precision machine, which must be very certain. This not only requires mold maintenance workers to have superb technology and excellent style, but also have a serious and responsible spirit. Therefore, we will introduce the precautions for mold maintenance. 1. Clean the metal shell and oxide skin around the mold to show the true color of the mold. 2. Refer to the last die-casting product sent with the mold for repair, and carefully check the problems of the mold. Check whether there is strain, clamping, crushing and meat dropping, whether the small core is bent or broken, whether the movable core is inserted and positioned incorrectly, whether the push rod is broken or the length of the push rod is changed, whether the insertion block is positioned incorrectly, and whether the fastening bolt is loose. Repair or replace according to the damage. 3. Cavity collapse, crack and block falling off that cause slight tensile damage to the casting can be repaired by local welding. Welding repair shall be carried out in strict accordance with the welding process, otherwise a lot of mold life will be lost. The above faults of small formed parts are more serious or the die is damaged. 4. If the forming surface of large forming parts is seriously collapsed, cracked, fallen off, etc., local welding repair can be carried out. Welding repair shall be carried out in strict accordance with the welding repair process, otherwise a large number of mold life will be lost. The above faults of small formed parts are more serious or the die is damaged. 5. Sliding parts such as core pulling mechanism and guide device shall be thoroughly cleaned, carefully inspected and maintained. Re lubricate with high-temperature grease before assembly. 6. If there is hydraulic core pulling, the hydraulic parts and molds shall be repaired at the same time. The maintenance of the hydraulic part shall pay special attention to cleaning to prevent pollution, otherwise the hydraulic system of the whole die-casting machine will be polluted. 7. When the mold breaks down or is damaged in the production project, the repair plan shall be determined according to the specific situation. If necessary, carry out comprehensive maintenance according to the above methods. 8. For the molds that need to be repaired and maintained, the forming surface, parting surface and mounting surface shall be subject to anti rust treatment, closed and fixed, and placed on the base plate according to the installation direction of the mold on the machine. Mold attachments are placed with the mold.

Die processing refers to the processing of forming and blank making tools, including die cutting die and shearing die. Generally, the mold consists of an upper mold and a lower mold. The material is formed under the action of a press, and the steel plate is placed between the upper mold and the lower mold. When the press is opened, the workpiece determined by the mold shape will be obtained or the corresponding scrap will be removed. Parts as large as automobile instrument panel and as small as electronic connector can be molded by mold. Progressive die refers to a set of dies that can automatically move the processed workpiece from one station to another, and obtain the formed part in the latter station. Die processing technology includes: four slider die, extrusion die, compound die, blanking die, progressive die, stamping die, die cutting die, etc. Basic characteristics of mold processing: 1. High processing precision. A pair of molds usually consists of a female mold, a male mold and a mold frame, some of which can be multi piece segmentation modules. Therefore, the combination of upper and lower dies, the combination of inserts and cavities, and the combination between modules all require high machining accuracy. 2. Complex shape and surface. For some products, such as automobile panels, aircraft parts, toys and household appliances, the molding surface is composed of various curved surfaces, so the mold cavity surface is very complex. Some surfaces need to be treated by mathematical calculation. 3. Small batch. Mold production is not batch production, and in many cases only one pair is produced. 4. There are many processes. Milling, boring, drilling, reaming and tapping are always used for mold processing. 5. Repeat production. The service life of the die is long. When the service life of a pair of dies exceeds their service life, new dies need to be replaced, so the production of dies is often repeated. 6. Profiling processing. Mold production sometimes has neither drawings nor data, and copying and processing should be carried out according to the actual object. This requires high imitation accuracy and no deformation. Mold processing flow: 1. Bottom processing, processing quantity guarantee; 2. Slab datum alignment, check 2D allowance and 3D profile; 3. Rough machining of 2D and 3D profiles, non installation and non work plane machining; 4. Before semi finishing, align the side datum plane to ensure accuracy; 5. Semi finish machining of 3D contour and 2D, semi finish machining of various guide surfaces and guide holes, finish machining of various installation working surfaces, allowance for finishing of process reference holes and height reference surfaces, and recording of data; 6. Check and recheck the machining accuracy; 7. Bench worker inlaying process; Align the datum plane of the process datum hole and check the allowance of the insert before finishing; 8、. Finish machining contour 2D and 3D, punching contour and hole position, finish machining guide surface and guide hole, finish machining process datum hole and height datum; 9. Check and recheck the machining accuracy. Notes: 1. The process is concise and detailed, and the processing content should be expressed in figures as much as possible; 2. Special emphasis shall be placed on the key points and difficulties of processing; 3. It is necessary to combine the processed parts and express the process clearly; 4. When the insert needs to be processed separately, pay attention to the technical requirements for processing accuracy; 5. After combined processing, for inserts that need to be processed separately, the benchmark requirements for independent processing shall be installed during combined processing; 6. The spring is easy to be damaged in die processing, so the die spring with long fatigue life should be selected.

Most of the current control systems can be traced back to the root of this system, that is, it has a history of 30 to 40 years. One of the bottlenecks was the download speed of the RS-232 connection. The program segment reading speed of this type of control system can reach 5000/s program segments. For many parts, this speed is enough, but for complex parts, the required speed is much higher. When Mr. Carlo Miceli of MTI began to develop his own control system, he adopted a new method for PC language logic and effective information processing. Its product is a CNC system based on modern PC hardware, equipped with a new tool path algorithm, and its reading speed reaches more than 5000/s program segments. GBI Cincinnati said that its results have met the requirements of "constant speed" processing, and its production speed is fast and the feed rate is very stable. The machine tool combines the rapidity of modern control technology with the precision of machine tool movement to form a real constant speed machining system. The control system of the machine tool may become an obstacle to shorten the machining cycle and improve the finish of complex 3D models, aerospace parts or medical device elements. When the processor cannot keep up with the program running speed, the driver will reduce the feed speed of the tool due to the urgent need for information, thus prolonging the processing cycle, resulting in the uncoordinated operation of the tool. In order to replace worn and overloaded tools, in addition to increasing the number of tool runs to the tool library, it will also affect the effective use rate of the spindle, increasing the workload of fitters and finishing time. When the speed (feed rate) is unstable, some problems will occur. When the tool runs through the part processing, its uneven movement will cause different loads on the cutting grooves on the tool, thus affecting the machining accuracy and surface finish. If the running speed of the tool is not fast enough to maintain the minimum cutting load of the tool, friction will occur between the tool and the workpiece instead of cutting, and the unstable motion of the tool will shorten the service life of the tool. Such operation mode will also cause a small amount of fracture notch of the blade, making the tool hot and blunt. However, with constant speed machining, the average processing speed of the tool through the workpiece will be more uniform and the processing accuracy will be higher, which can not only shorten the processing time, but also extend the service life of the tool. In the "revolutionary" series of machining centers, MTI's control system will not generate excessive stress related to high-speed machining, allowing fluid tools to operate on the geometry of complex parts. In the process of program execution, the result of high-speed program segment processing is that the random error of the control system can be monitored and adjusted stably, so that the tool can run at a uniform speed and achieve a perfect surface integrity. The system uses more than 80 high-speed buffers to monitor the operation of the tool. If the random error is exceeded, the motion of the tool can be adjusted immediately. Even when machining very complex shapes, it is said that the speediness of the control system, the fine adjustment of the driver and the processing of the tool path can achieve the goal of fast and accurate program execution.