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Structure Optimization of Rotary Blow Molding Machine Frame

In recent years, with the continuous development of the beverage, food, and medical industries, the demand for PET bottles with many excellent properties has also increased year by year, which requires that the efficiency of the PET bottle blowing machine can be improved. At present, the common bottle blowing machines on the market mostly adopt a two-step production process (the preparation of the preform and the stretch blow molding are completed by two equipments respectively), mainly linear blow molding machines and rotary blow molding machines. Compared with the linear bottle blowing machine, the rotary bottle blowing machine has the advantages of large number of cavities, quick mold replacement, high output, and strong stability. It has become the object of choice for most food and beverage companies. Due to the late start of domestic PET bottle forming equipment, although it has developed rapidly in recent years, there is still a certain gap in the technical level and performance of the equipment compared with those overseas PET bottle forming equipment R&D companies with a long history.

As one of the important parts of the rotary blow molding machine, the blow molding machine frame supports the weight of the entire rotary stretch blow molding part. The rigidity, strength and stability of its structure play a vital role in the operation of the entire equipment effect. Therefore, how to improve the static and dynamic performance of the frame has become one of the key issues in the design of high-speed rotary blow molding machines. In recent years, with the rapid development of computer technology, structural optimization methods and computer technology have gradually achieved a perfect integration. Many large-scale general CAE analysis software have appeared in structural optimization modules, which greatly improved the efficiency and accuracy of structural optimization analysis. improve.The frame of the rotary bottle blowing machine studied in this paper is welded by four parts, namely the upper panel, the middle panel layer, the lower panel and the footing. The middle panel layer is directly welded by many monolithic steel plates. The quality of the rack itself is increased, and the manufacturing cost of the enterprise is increased. In order to achieve the purpose of reducing the quality of the rack and improving its static and dynamic performance.
  1 The initial static and dynamic characteristics analysis of the frame
1.1 Establishment of the finite element model of the frame The geometric dimensions of the frame are: 4150mm×3750mm×547mm, the upper and lower panels are made of low-alloy high-strength steel, the yield limit is about 400MPa, and the materials of the middle panel layer and the footing are ordinary carbon. For structural steel, the yield limit is about 220MPa. According to the Saint-Venant principle, the three-dimensional model of the rack is reasonably simplified.
  1.2 Static analysis of frame
  1.2.1 Contact and restraint settings
Because the frame is welded by multiple steel plates of different sizes, it can be regarded as a welded structural part, no need to set up contact, just import the three-dimensional model of the frame into Workbench, enter the DesignModeler environment, and then select all parts Right-click FromNewPart, so that all parts can be grouped into one part, the common interface shares the grid, and the nodes are coupled. The restraint of the frame is set as fixed restraint on the bottom surface of the four feet.
  1.2.2 Load setting
The load on the frame has 9 main parts, which are the weight of the rotating moving parts, the weight of the opening and closing mold guide, the weight of the opening and closing guide rail, the weight of the star wheel for taking and sending blanks, the weight of the star wheel for taking and sending bottles, and the deceleration. The weight of the motor, the weight of the transition pulley set 1, the weight of the transition pulley set 2 and the weight of the transition pulley set 3, among which the slewing parts need to be set with a safety factor of 1.25.
   1.2.3 Static analysis results
   Through the static analysis of the frame, it can be seen that the original design of the frame was too conservative, resulting in a waste of materials, so the frame structure needs to be further optimized to reduce the quality of the frame.More about:Water Bottle Machine 600ML 5000BPH MST 68/4