Simple grinding and grinding method of blanking mould for bottom of steel drum
The bottom drum blanking mould for steel drums is an indispensable tooling mould for steel drum production enterprises. In recent years, with the advancement of technology and the development of science and technology, steel drums have gradually begun to develop in the direction of thinning. In order to reduce production costs and investment costs, steel drum companies have tried every means to satisfy their production and production processes.
In the past, old steel drum companies often used large horse-drawn carts to meet the normal installation of blanking molds for the bottom cover of steel drums. Buy crank presses for large countertops, and as the crank press table increases, its tonnage increases accordingly. For example, many old steel barrel companies use the 400 tons press, 250 tons of closed single point presses and 160 tons of closed single point presses when stamping the bottom of the barrel. In fact, in terms of its blanking force, a 160-ton press can meet its requirements. Moreover, the price of open presses is much lower than that of closed presses, but due to the insufficient size of the press table, many steel drum companies are forced to purchase large tonnage presses at all costs. This not only increased the investment costs at the initial stage of corporate investment, but also caused troubles in the subsequent installation, maintenance, and use.
In recent years, forging equipment manufacturers have made great contributions to the development of steel barrel enterprises. They are in urgent need of users and have specially developed 100 tons and 160 tons of open single column fixed tables for the steel barrel industry to increase the work surface. Presses. As a result, equipment investment costs and plant investment costs of steel barrels are reduced. And laid a solid foundation for energy conservation in its future production. Zhejiang Jingxian Drum Machinery Mould Factory plays a decisive role in the rapid development of steel drum thinning. It is the only professional manufacturer in China to produce steel drum moulds. They designed the barrel lids of the 200-liter steel barrels to be curved curved blanking edges. The production of barrel lids using this edge blanking die can not only reduce the blanking during die blanking. Force, but also reduces the type and tonnage of the punch press when punching the lid. At present, there are already 100 sets of steel drum molds produced by this factory. Most steel drum manufacturers use the mold for a long time. Now, the cutting edge of the mold slowly enters the passivation and aging stages. If the blanking continues, it will not only seriously affect the quality and appearance quality of the drum, but also affect the service life of the die. For this reason, our factory actively organized personnel to repair this mold. The following is a little experience of our factory when dealing with this mold, for reference by peers.
For more than a year, the quality of the lid of the 200-liter full-opening steel drum produced by our factory has been trapped around us. Since the 200-liter full-opening drum cover mould of our factory has already stamped more than 100,000 barrel lids, the mold blanking The edge is obviously aging, and the thickness of the material of the steel drums manufactured by our factory changes greatly. There are steel plates with a thickness of 0.8 mm, steel plates with a thickness of 1.0 mm, and steel plates with a thickness of 1.2 mm. The difference in the mechanical properties of these materials is also serious. Such materials are used to make the lids, and the damage to the molds itself is very great, resulting in the stamped lids having three distinct protrusions and peripheral tearing burrs. Recently, the protruding nozzles and burrs have become more serious and have directly affected the quality of our 200-liter full-open steel drums.
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 product costs, in order to meet market demand, in line with the development trend of thin steel drums, on the basis of the original The raw materials for making steel drums will be further thinned. This increases the difficulty of production of steel drums, of which the most difficult ones are the barrels of full-open barrels and the bottom of 200-liter steel barrels. Because it has already been introduced before, the barrel lid of the 200-liter full-opening drum lid mould has already had three prominent protruding mouths and burrs. Moreover, at the time, the cutting edge clearance of the die was designed as a steel plate with a material thickness of 1.2 mm. Using it to punch thin steel plates will not only produce burrs due to excessive mold clearances, but also cause warpage inequality due to thin materials. In order to ensure product quality, we have repeatedly studied and discussed and decided to grind the mold. Since the punching edge of the 200-liter full-opening steel barrel lid mould of our factory is a curved surface, it is more difficult to grind the curved surface edge. First of all, the grinding of the edge must be performed on a curved grinding machine; secondly, due to the cutting edge of the mold. After a long time of use, the radius of curvature is different. Because the degree of wear of the mold itself is not the same, the use of a curved grinding machine can not guarantee the service life and accuracy of the mold; Third, the curve grinder in our local only 1 to 2 Taiwan, and all imported equipment, each time you need to start spending 3,000 yuan. Therefore, the cost of grinding is too high to guarantee the normal use of the mold.
In order to reduce costs, ensure the quality of molds and product quality, we decided to break the traditional method of grinding, and our own maintenance staff used hand-grinding wheels to grind. Because we have used whetstones to polish many times before, it has had little success. To this end, we set up technical personnel on-site guidance, senior die-matter fitter major team, using a portable grinder (universal angle grinder) to grind such a large mold, for our factory, for the first time , so everyone in our group has a lot of ideological pressure. However, everyone worked together to offer advice and suggestions. After three days of intense and orderly work, the molds were repaired and the edges were ground. After the molds were closed and the mold gaps were evened out, the molds were installed on the punching bed to test the molds. After the original nose was gone, the burrs were significantly reduced, the lids were sleek and beautiful, and thin plates could also punch out qualified products. Now, our molds have stamped more than 10,000 barrel lids, and all of our quality has met the requirements. In order to attract attention, we now introduce this experience as follows:
1, the use of manual grinding mold, the operator of the operation of the universal angle grinder is more demanding, this person needs superb skills (advanced mold fitter) and excellent hand operation.
2. When grinding, the cutting edge of the mold should be placed on a rotating rotating bracket.
Under normal circumstances, the bracket can not be too high, the height of about 500 ~ 600mm, easy to operate. And to have a certain degree of strength and stability, so that the edge of the mold on the bracket to ensure its safety, will not fall or collapse the bracket, thereby damaging the edge of the mold. When making a stand, it is best to use a turntable with a bearing. If possible, electric brackets can also be used, but the rotational speed requirement is very low. Because the die edge is free to be placed on the bracket turntable, the rotational speed of the turntable must not be too high, so that the edge of the die can be thrown from the turntable.
3, grinding, the amount of feed can not be too large, so as not to cause die edge annealing, so that the mold scrapped.
When grinding, the operator holds the universal angle grinder in one hand and only needs to gently touch the surface of the cutting edge of the cutting wheel, ie, the depth of each grinding cannot exceed 0.01 mm. Since the edge of the die has been heat-treated during mold making, if the amount of feed is too large during the grinding process, the mold heat is severe, causing partial annealing. After annealing, the strength of the die is reduced and stamping cannot be performed; Die can not be re-quenched, one is after annealing, due to different degrees of annealing, re quenching quenching is not on; the second is even if quenching the fire, due to a large deformation of the quench, the upper and lower die edge gap will be destroyed, so that Die scrapped. In order to ensure that the heat treatment hardness and the mold are not damaged, so the amount of each feed should be as small as possible.
4, when grinding, be sure to add lubricants, cutting oil or oil.
In order to reduce the heating of the mold during grinding, it is necessary to add lubricant to the mold grinding surface, that is, to add cutting oil or oil.
5. When grinding, manual grinding wheel hand feed, mold edge should be evenly rotating on the movable support.
During the work, the operator holds the angle grinder in one hand and only moves in the up and down direction. Since the surface of the cutting edge is curved, it is uneven and needs only slight contact, so be sure to grasp its height at any time; the other hand gently turns the dial It is necessary to keep the rotation speed of the turntable even while ensuring that the rotation speed cannot be too high or too low. Under normal circumstances, keep 40 to 50 rpm.
6. Before grinding, use a small grinding head or polished emery cloth to sharpen the mold edge to the mirror surface.
After using a hand-held trowel machine to grind the cutting edge, due to the small size of the grinding wheel of the portable grinding wheel, the roughened surface of the cutting edge can not meet the requirements of the processing precision of the mold. Therefore, the edge of the grinding needs to use a small grinding head. The polishing machine grinds or polishes the emery cloth and polishes it to the mirror surface, thereby ensuring the accuracy of the mold.