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Mold structure and working process The mold structure is shown on the 10000kN screw press with a mold closing height of 720mm. If used on a crank press, increase the height of the punch or reduce the thickness of the pressure ring 3 to ensure the mold is closed. In the state, the pressure ring does not contact the die (generally there should be a distance of 10 mm or more). The protruding feature of the mold is that a back pressure energy mechanism capable of generating a compensation space is provided, which is mainly composed of an anvil ring 5, an output device, a push rod, a push rod, a disc spring, a support block and a sink seat. Before forging, under the action of the disc spring, the output device and the anvil ring are at their upper limit positions. When forging, the upper and lower molds are pressed, that is, the pressure ring and the concave mold are attached, and the deformed metal pushes the movable anvil ring and the output device downward to move a small distance (compensation space height), the disc spring is compressed, and the blank is redundant. The metal is extruded onto the hub of the forging and the lower end of the rim, thereby ensuring that the forging web thickness meets the dimensional requirements, while the back pressure created by the disc spring flattens the end of the forging. After the forging is completed, the upper die is lifted and the forging is left in the die. Under the action of the disc spring tension, the output device and the movable anvil ring return to the initial position, pushing the forging up distance. The press ejector system then pushes the forging out of the die through the pusher, pusher and kicker. Since the forging has been pushed by the disc spring tension before the lower pusher top member.
The design of the cylindrical gear precision forging die with compensation space is to determine the horizontal projection size of the compensation space. In order to make the mold compact, the volume of the composite disc spring should be minimized, that is, the required back pressure should be minimized. Therefore, under the condition that the excess metal can smoothly enter the compensation space, the horizontal projected area of ​​the space is compensated, that is, the annular cross-sectional area of ​​the output device and the anvil ring should be as small as possible. The cross-sectional dimension of the injector 6 is the same as that of the forging hub end face; the inner diameter of the movable anvil ring is the same as the inner diameter of the forging rim, and the outer diameter is 166 mm, which is 13 mm smaller than the outer diameter of the forging rim. The inner wall of the die is correspondingly provided with a width. For the step of 6.5mm, compared with the step without the concave die (the outer diameter of the anvil ring is 179mm), the total horizontal projection area of ​​the compensation space is reduced by 33, that is, the required back pressure is reduced. 33. The maximum height of the compensation space is calculated first. Calculate the volume of metal that the compensation space should accommodate. According to the size (or weight) of the forging, 70mm round steel is used as the raw material, and the length of the block is initially determined to be 133.3mm. The difference between the diameter error of the round steel and the length of the blank is less than 2, and the relative error of the block volume is not more than 2, The maximum amount of burn-in of the medium-frequency induction heating 1.2 is calculated by V, the output and the inner and outer diameters of the anvil ring. The maximum value of the compensation space height h is hmax=2.3mm. The disc spring design is based on the output device and the anvil ring. Dimensions, as well as the requirement to ensure the basic flattening of the forging hub and the lower end of the rim, calculate the required back pressure P = 858kN. Consider stacking four disc springs and then combining them to form a composite disc spring. The composite disc spring has a free height of 119.5mm, a preload of 3.5mm, and a maximum working compression (excluding preload) of 2.3mm. The allowable ultimate compression is 75 for the disc spring flattening of 9mm, which is 6.75mm, and the preload is 550kN. The maximum working pressure is 911kN, and the allowable limit pressure is 1060kN. Since the allowable limit pressure of the disc spring has a large margin compared with the maximum working pressure, and the working stroke (working compression amount) is small, it belongs to the class variable load disc spring. The number of work is above 106, so its life is very high.
The disc spring seat design seat is used to support the composite disc spring. Because the forging plate is thin and the horizontal projection area is large, the forming of the web requires a lot of pressure. The forging deformation force of the equipment is mostly transmitted from the fixed anvil ring to the pressure plate, and only a small part consists of a sinking seat and a concave die (the inner wall step) )bear. Therefore, under the condition that the strength requirement is fully satisfied, the wall thickness of the seat should be as small as possible to avoid weakening the supporting effect of the lower die seat on the pressure plate and ensuring the strength of the pressure plate. The wall thickness of the sink seat is set to 17mm, and the tensile strength of the sinker wall still has a large margin. Pressure plate threaded hole design When the pressure plate 2 and the upper mold base 1 are tightly fitted, the pressure plate is removed from the upper mold base and the long bolt is used to screw the pressure plate into the threaded hole. Therefore, the pressure plate 2 The upper surface of the four threaded holes is designed as a through hole having a diameter larger than the outer diameter of the thread, which is convenient for the pressure plate to be disassembled and easy to process, and avoids time and labor for processing the full thread. From the actual situation of the application of CNC machining technology at present, combined with the author's practical experience, from the production management, design and development and manufacturing mode, the information construction of the process, the preparation and management of CNC machining technology and procedures, CNC talents The cultivation and other aspects explored the ways and measures for the realization of high-efficiency CNC machining.
As a representative of advanced productivity, CNC machining has played an important role in the manufacturing fields of automobiles, molds, aerospace, machinery and electronics. Numerical control technology has greatly promoted the development of productivity in scientific research and production. The introduction of its technology and its application in domestic research and production have been for 10 years, but in different industries in China, the gap in its application level is obvious, and each has its own advantages. The application of CNC machining technology has improved the development of traditional manufacturing industry as a whole. How to achieve high-efficiency CNC machining for manufacturing enterprises to form core competitiveness has always been one of the concerns of enterprise managers and researchers.
August 04, 2021