Simple grinding method of blanking forming die for

2022-10-16
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The simple grinding method of the blanking forming die at the bottom and top of the steel barrel

the blanking forming die at the bottom and top of the steel barrel is an essential tooling die for the steel barrel production enterprises. In recent years, with the progress of technology and the development of science and technology, steel barrels gradually began to develop in the direction of thin. In order to reduce production costs and investment costs, steel barrel enterprises try every means to meet their production and production processes

in the past, in order to meet the normal installation of the blanking forming die of the bottom cover of the steel barrel, the old steel barrel enterprises often used the method of pulling a cart with a big horse. Buy a crank press with a large table, so as the working table of the crank press increases, its tonnage will increase accordingly. For example, when stamping the bottom and top of the barrel, many old steel barrel enterprises mostly use 400 ton press, 250 ton closed single point press and 160 ton closed single point press. In fact, in terms of blanking force alone, a 160 ton press can meet its requirements. Moreover, the price of the open press is far lower than that of the closed press, but it is only because the size of the working table of the press is not enough, which forces many steel barrel enterprises to buy large tonnage presses at all costs. This not only increases the investment cost at the initial stage of enterprise investment, but also brings trouble to its later installation, maintenance and use

in recent years, forging equipment manufacturers have made great contributions to the development of steel barrel enterprises. They are anxious to meet the needs of users. They have specially produced 100 ton and 160 ton open single column fixed table presses with enlarged worktops for the steel barrel industry. Thus, the equipment investment cost and plant investment cost of steel barrel enterprises are reduced. And laid a solid foundation for energy conservation in its future production. Zhejiang Quxian steel barrel machine mould factory plays a decisive role in the rapid development of thin steel barrel. It is the only professional manufacturer of steel barrel mould in China. They designed and made the ends of the 200 liter steel barrel series products into curved blanking and drawing edges. Using the blanking and drawing die with this edge to produce the ends can not only reduce the blanking force when the die is blanking, but also reduce the equipment model and tonnage of the punch when stamping the ends. At present, the factory has produced hundreds of sets of steel barrel molds, and most steel barrel manufacturers have used this mold for a long time. Now, the blanking edge of the mold is slowly entering the passivation and aging stage. If blanking is continued, it will not only seriously affect the sealing quality and appearance quality of the steel barrel, but also affect the service life of the die. To this end, our factory actively organized personnel to repair this mold. The following is our experience in dealing with this mold for peer reference

for more than a year, the quality of the end of the 200 liter full open steel barrel produced by our factory has been troubling us. Because the 200 liter full open steel barrel end mold of our factory has punched more than 100000 end pieces, the blanking edge of the mold is obviously aging, and the material thickness of the steel barrel produced by our factory changes greatly. There are steel plates with a thickness of 0.8mm, 1.0mm and 1.2mm. There are also serious differences in the mechanical properties of these materials. Such materials are used to make the barrel cover, which will cause great damage to the mold itself, resulting in three obvious protruding nozzles and peripheral tearing burrs on the stamped barrel cover. Recently, the protruding nozzle and burr have become more serious, which directly affects the product quality of our 200 liter full open steel barrel

at present, it is the harvest season of agricultural and sideline products and the peak sales season of full opening steel barrels. Due to the sudden rise in raw material prices, users have to reduce product costs. In order to meet the market demand, in line with the development trend of thin steel barrels, the raw materials for making steel barrels will be further thinned on the original basis. This increases the difficulty in the production of steel barrels, of which the most difficult are the full open barrel cover and the bottom of the 200 liter steel barrel. As mentioned earlier, there are three obvious bumps and burrs on the end of the 200 liter full open steel barrel stamped by the end mold of our factory. Moreover, at that time, the die edge clearance was designed according to the steel plate with a material thickness of 1.2mm. Using it to punch thin steel plates will not only produce tearing burrs due to too large die clearance, but also produce warpage inequality due to too thin material. In order to ensure product quality, the total demand for polyurethane in the Asia Pacific region is about 7million tons per year. After repeated research and discussion, we decided to grind the mold. Because the blanking edge of the 200 liter full open steel barrel cover mold of our factory is a curved surface, and the grinding of the curved edge is more difficult, first of all, the grinding of the edge must be carried out on the curve grinder; Secondly, because the radius of curvature of the die edge is different after long-term use, because the wear degree of the die itself is different, the service life and accuracy of the die cannot be guaranteed after grinding with a curve grinder; Third, there are only 1-2 curve grinding machines in our local area, all of which are imported equipment, and each start-up costs 3000 yuan. Therefore, the grinding cost is too high, and the normal use of the mold cannot be guaranteed

in order to reduce costs and ensure mold quality and product quality, we decided to break the traditional grinding method and have our own maintenance personnel use manual grinding wheels for grinding. Because we have used oilstone to polish many times before, but with little effect. For this reason, we have set up a research group with on-site guidance of technicians and major in senior die fitter. It is the first time for our factory to use a portable grinder (Universal angle grinder) to repair such a large die, so everyone in our group has a lot of thinking pressure. But everyone worked together and offered suggestions. After three days of intense and orderly work, the mold was repaired and the cutting edge was grinded out. After the mold was closed, the gap between the molds was adjusted to be uniform, and the mold was installed on the punch to test the mold. After use, the original nozzle was gone, the burr was significantly reduced, the barrel cover was smooth and beautiful, and the sheet metal was able to punch qualified products. Now, our mold has stamped more than 10000 barrel covers, and the quality has all met the requirements. In order to attract jade, this experience is introduced as follows:

1. Manual grinding of the mold requires high requirements for the personnel who operate the universal angle grinder. This person needs exquisite skills (senior mold fitter) and excellent hand operation skills

2. During grinding, the die edge should be placed on a rotating support with flexible rotation

generally, the support should not be too high, with a height of about 500~600mm, which is convenient for operation. And it should have a certain strength and stability, so that the die edge is placed on the support to ensure its safety, and will not fall down or collapse the support, thereby damaging the die edge. When making the support, it covers plastic, food, personal care products, medicine and medical treatment, non-woven, paint and ink, automobile, metal, mold, packaging, composite materials, and health anti-aging, innovative materials series forums for innovative technologies and popular markets. It is best to use the turntable with bearing. If possible, the electric support can also be used, but the speed requirement is very low. Because the die edge is freely placed on the support turntable, it is forbidden to throw the die edge out of the turntable because the turntable speed is too high

3. During grinding, the feed amount should not be too large, so as to avoid annealing of the die edge and scrapping of the die

when the operator is grinding, hold the universal angle grinder in one hand, and only need the grinding wheel to gently contact the surface of the die edge, that is, the grinding depth each time cannot exceed 0.01mm. Because the die edge has been overheated during die manufacturing, if the feed rate is too large during grinding, the die will heat seriously, resulting in local annealing. After annealing, the die strength will be reduced, and its change law will be analyzed to judge the wear degree, so stamping is not allowed; In addition, the annealed mold cannot be quenched again. First, after annealing, due to different degrees of annealing, it cannot be quenched again; Second, even if it can be quenched, due to the large quenching deformation, the gap between the upper and lower die edges will be destroyed, so that the die will be scrapped. In order to ensure that its heat treatment hardness and mold are not damaged, each feed should be as small as possible

4. When grinding, be sure to add lubricant, cutting oil or engine oil

in order to reduce the mold heating during grinding, it is necessary to add lubricant to the grinding surface of the mold during grinding, that is, add cutting oil or engine oil, etc

5. During grinding, the hand-held grinding wheel shall be fed manually, and the die edge shall rotate evenly on the movable support

when working, the operator holds the angle grinder in one hand and only moves up and down. Because the surface of the cutting edge is curved and uneven, it only needs to touch gently, so it must master its height at any time; Turn the turntable gently with the other hand, not only to keep the rotating speed of the turntable uniform, but also to ensure that the rotating speed cannot be too high or too low. Generally, keep 40~5, then 0 rpm

6. Before grinding, use a small grinding head or polishing abrasive cloth to grind the die edge to the mirror surface

after grinding the edge with a portable grinder, because the particle size of the portable grinding wheel is small, the surface of the grinding edge is rough, which can not meet the requirements of mold processing accuracy. Therefore, the polished edge needs to be polished with a small grinding head polishing machine or polished with abrasive cloth to the mirror surface, so as to ensure the accuracy of the mold

Author: Xin qiaojuan

source: China steel drum packaging

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