Simple grinding method for the bottom blank forming die of steel drum

Simple grinding method for the bottom blank forming die of steel drum

Xin Qiaojuan

The bottom blank forming die of steel drum is an indispensable tooling die for steel drum manufacturers. In recent years, with the advancement of technology and the development of science and technology, steel drums have gradually begun to develop toward thinning. In order to reduce production costs and investment costs, steel drum companies have tried every means to meet their production and production processes.

In the past, the old steel drum enterprises often used the large-marathon trolley in order to meet the normal installation of the blank forming die of the steel drum bottom cover. The crank press for the large countertop is purchased, so that as the working surface of the crank press increases, the tonnage increases accordingly. For example, many old steel drum companies use 400 tons of presses, 250 tons of closed single point presses and 160 tons of closed single point presses when stamping the bottom of the barrel. In fact, the 160-ton press can meet its requirements in terms of its blanking power. Moreover, the price of open presses is much lower than that of closed presses, but only because the press table size is not enough, forcing many steel drum companies to buy large-tonnage presses at all costs. This not only increases the investment cost in 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 drum enterprises. They are anxious for users to produce 100-ton and 160-ton open single-column fixed tables for the steel barrel industry. Press. Thereby reducing the equipment investment cost and factory investment cost of steel drum enterprises. And laid a solid foundation for saving energy in future production. Zhejiang Yixian Steel Barrel Machinery Mould Factory plays a decisive role in the rapid development of steel drum thinning. It is the only professional manufacturer in China that produces steel drum molds. They designed the lids of the 200-liter steel drum series into a curved-shaped blanking cutting edge. The production of the barrel lid by the blanking die of this cutting edge can not only reduce the blanking of the mold when blanking. Force, but also reduce the type and tonnage of the press when punching the lid. At present, there are hundreds of steel drum molds produced by the factory, and most steel drum manufacturers have used this mold for a long time. Now, the blanking edge of the mold slowly enters the passivation and aging stage. If the punching continues, it will not only seriously affect the quality and appearance quality of the steel drum, but also affect the service life of the mold. To this end, our factory actively organizes personnel to repair the mold. The following is a little experience of our factory in dealing with this mold, for peer reference.

Over the past year or so, the quality of the lid of the 200-liter full-open steel drum produced by our factory has been plagued by us. Since our 200-liter full-open steel barrel lid mold has been stamped with more than 100,000 barrel lids, the mold is blank. The cutting edge is obviously aging, and the thickness of the material used to make the steel drum varies greatly. There is a steel plate having a thickness of 0.8 mm, a steel plate having a thickness of 1.0 mm, and a steel plate having a thickness of 1.2 mm. The mechanical properties of these materials are also quite different. Such materials are used to make the lids. The damage to the mold itself is so great that the stamped lids have three distinct noses and peripheral tearing burrs. Recently, the nose and burrs have been further serious, which directly affected the quality of our 200-liter full-open steel drum.

At present, it is the harvest season of agricultural and sideline products, which is also the peak season for the sales of fully open steel drums. Due to the sudden increase in raw material prices, users have to reduce the cost of products. In order to meet the market demand, in line with the development trend of thin steel drums, on the original basis The raw materials for making steel drums are further thinned. This increases the difficulty in the production of steel drums, the most difficult of which is the full-open bucket lid and the bottom of the 200-liter steel drum. As already mentioned in the previous section, there are already three obvious noses and burrs in the lid of the 200-litre full-open steel barrel lid mold stamped out. Moreover, the die edge gap was designed according to the steel plate with a material thickness of 1.2 mm. It is used to punch thin steel sheets, which not only causes tear burrs due to excessive mold gap, but also causes warpage inequality due to too thin material. In order to ensure the quality of the products, we have decided to repair the mold after repeated research and discussion. Since the cutting edge of the 200-liter full-open steel barrel lid mold of our factory is curved, and the curved edge grinding is difficult, firstly the grinding of the cutting edge must be carried out on the curved grinding machine; secondly, due to the cutting edge of the mold After a long period of use, the radius of curvature varies greatly, because the degree of wear of the mold itself is different, and the service life and accuracy of the mold cannot be guaranteed after grinding with a curved grinding machine. Third, the curve grinding machine is only 1~2 in our local area. Taiwan, and all imported equipment, it costs 3,000 yuan per start. 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, which was repaired by our own maintenance personnel with manual grinding wheels. Because we used to grind many times with oilstone, but the results are very small. To this end, we set up a technical staff on-site guidance, the advanced mold pliers major in the research team, using a hand grinder (universal angle grinder) to repair such a large mold, for our factory, for the first time So everyone in our group has a lot of thought pressure. But everyone worked together to make suggestions and suggestions. Through three days of intense and orderly work, the mold was repaired, and the cutting edge was ground out. After the mold was closed, the mold gap was adjusted to be uniform, and the mold was installed on the punching machine to test the mold. After the original nozzle is gone, the burr is also significantly reduced, the lid is smooth and beautiful, and the thin sheet can also punch out qualified products. Now, our molds have been stamped more than 10,000 barrels, and the quality has reached the requirements. In order to attract the jade, the experience is as follows:

1. The manual grinding mold is used to meet the requirements of the personnel who operate the universal angle grinder. This person needs to have exquisite skills (advanced mold fitter) and excellent hand operation.

2. When grinding, the die edge should be placed on a rotating rotating bracket.

Under normal circumstances, the bracket should not be too high, and the height is about 500~600mm, which is easy to operate. It must have a certain strength and stability, so that the die edge is placed on the bracket to ensure its safety, will not fall down or collapse the bracket, thus damaging the die edge. When making the bracket, it is best to use a turntable with bearings. If possible, electric brackets can also be used, but the speed requirement is very low. Since the die edge is freely placed on the bracket turntable, the rotation speed of the turntable should not be too high, and the die edge can be pulled out from the turntable.

3. When grinding, the amount of feed can not be too large, so as to avoid the annealing of the die edge, so that the mold is scrapped.

When the operator is grinding, the hand grinder is held in one hand, and only the grinding wheel piece gently touches the surface of the die edge, that is, the grinding depth cannot exceed 0.01 mm each time. Since the die edge has been heat treated during the mold making process, if the feed amount is too large during the grinding process, the mold heat is severe, causing local annealing, and after annealing, the die strength is lowered and cannot be punched; in addition, after annealing The mold can not be quenched again. One is that after annealing, the quenching can not be quenched due to different annealing degrees. The second is that even if quenching is possible, the gap between the upper and lower mold edges will be destroyed due to the large quenching deformation. The mold is scrapped. In order to ensure that the heat treatment hardness and the mold are not damaged, the feed amount should be as small as possible.

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

In order to reduce the heat generated by the mold during grinding, it is necessary to add lubricant to the grinding surface of the mold during grinding, that is, adding cutting oil or oil.

5. When grinding, the hand-held grinding wheel is manually fed, and the die edge should be evenly rotated on the movable bracket.

When working, the operator holds the angle grinder in one hand, but only moves in the up and down direction. Because the surface of the cutting edge is curved, the height is uneven, just touch it gently, so be sure to grasp the height at any time; the other hand gently rotates the turntable. It is necessary to keep the rotating speed of the turntable even and ensure that its speed cannot be too high or too low. Under normal circumstances, keep 40~50 rev / min.

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

With the hand-held turret, after grinding the cutting edge, the surface of the grinding wheel is rough due to the small grain size of the grinding wheel, which can not meet the requirements of mold processing precision. Therefore, the grinding edge needs a small grinding head. The polishing machine grinds or polishes the abrasive cloth to the mirror surface to ensure the accuracy of the mold.