Design process scheme of the hottest cone crusher

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The lower frame of the cone crusher is the main structural part of the cone crusher and the assembly basis of other parts of the cone crusher. The lower frame of this structure contracted by our factory has never been produced before, so we can't borrow the past process ideas, and we can only find another way. By analyzing the casting structure and comprehensively considering the riser placement, pattern structure and gating system, a reasonable process scheme was designed, and the castings with user satisfaction were produced

1. Structural features of the lower frame

the lower frame is made of gs20mn5, with a maximum overall dimension of 2410mm and a height of 1070mm. Its structure is shown in Figure 1

there are many T-shaped joint structures and hot spots in this casting, which makes it difficult to arrange the feeding riser, especially the four convex joints around the joint with the main body, and the convex parts above the gear cavity in the front joint with the main body. These parts have a narrow space. If ordinary concealed joints are placed, the size will be large, which will increase the difficulty of subsequent cleaning. At the same time, these parts are also parts with high quality requirements of the casting, which need ultrasonic flaw detection, Therefore, it is difficult to guarantee the quality of castings without riser

its repair is more difficult than other environmental experimental facilities. 2 Process plan

(1) riser design for steel castings, the quality of riser design will directly affect the quality of castings. According to the structural characteristics of the lower frame, it is proposed to arrange a circle of risers on the flange, place a hidden riser (1 riser) in the middle and add subsidies, place a hidden riser (2 riser) at the intersection of the peripheral bulge and the main body, add subsidies to the flange at the intersection of the gear cavity and the main body, and then place a relatively large riser (3 riser) on the flange, as shown in Figure 2

through modulus method, 2 riser m ≥ 4cm, so the riser diameter should be ≥ 240mm. Due to the large size and narrow space of the riser, it is difficult to place it and inconvenient to shape it, which makes the subsequent cleaning very difficult. Therefore, we can not only increase the effective modulus by 1.5 ~ 1.7 times by using the formed insulation riser, but also it is much easier to place it in the shape, which is directly buried in the sand mold. Moreover, the riser size is also greatly reduced, which saves gold in the order amount of the industrialization of bio based chemical fibers and improves the process yield. The intersection of the protruding part on the gear cavity and the main body is a large hot joint, and a riser needs to be placed to supplement it, but if a riser is placed here to supplement it. Considering these factors, we decided to increase the riser corresponding to the upper flange, and increase the riser allowance between the riser and the bulge, which can also play the effect of shrinkage, and the shape is also much more convenient

(2) design of pattern structure due to the complex structure of castings, in the past, similar castings used multiple sand cores to form a mold cavity, but this often led to large cumulative dimensional deviation of castings. In order to reduce the dimensional deviation of castings, it is necessary to reduce the core and make the positioning datum of sand mold and sand core as unified as possible, so as to avoid the cumulative error in the process of core assembly and improve the dimensional accuracy of castings. The lower frame adopts a reference core. When closing the box, first place this reference core (at the bottom), and then locate other cores by it. From the practical application results, the effect is good, and the dimensional error is greatly reduced

(3) the design of the pouring system, the total weight of molten steel in the lower frame is 9800kg, and the pouring time is about 100s. Cast steel has high melting point, poor fluidity and large scouring to the mold cavity. In order to make the mold filling fast and stable, the bottom injection buffer gating system is used for the lower frame casting. After calculation, the flange is the position with the largest cross-section of the casting, and there are many risers on the flange. In order to prevent the steel liquid from rising too slowly in this cross-section, the riser cannot be filled, which affects the feeding effect of the riser, a layer of supplementary pouring gate is added at the flange to improve the pouring speed here, so that the metal liquid can rise rapidly and fill the mold cavity, avoiding the casting defects such as cold shuts

3. Process effect

according to this process plan, after the process verification of the first piece, we have produced 4 pieces continuously (which are still in production now), with few defects such as shrinkage and porosity, good casting quality, all qualified ultrasonic detection J, and achieved good economic benefits

4. Conclusion

(1) the use of insulated concealed risers can reduce the size of risers, facilitate modeling, and reduce subsequent cleaning; At the same time, reduce the amount of molten steel, improve the process yield, and reduce the consumption of raw materials and energy

(2) the bottom injection buffer gating system can fill the mold quickly and smoothly, which will have a certain change in the friction coefficient of the material surface and have a good effect on the quality of castings

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