INTRODUCTION
Spin pressure forming technology refers to the realization of some plastic deformation without high temperature under the action of pressure and radial force generated by rotating pressure head. The spin pressure deformation technology can be used in various fields such as automobile, aerospace, precision instruments and metallic plastic molding. Its advantages are: the production speed is fast, the deformed parts have high efficiency, beautiful shape, improving the utilization of materials, no pollution, good repeatability and rationality of production. In recent years, domestic and foreign spinning process research has become a hot spot in the research of sheet forming process, and many excellent results have been obtained.
The spinning pressure forming technology has the advantages of simple structure, convenient and fast operation, low cost of manufacturing equipment and so on. Due to the physical properties and mechanical properties of the materials, the spinning process can only be applied to some materials under certain conditions. It has been successfully used in manufacturing aviation and aerospace parts, auto parts, weapons, cameras and other precision parts with complex shapes. In industry, spinning is commonly used for cylindrical parts. There are two main forms of deformation: radial closed die and axial die. According to the difference of the material used for deformation, spinning can be divided into cold spinning and hot spinning. For cold spinning, the common forming materials are aluminum, copper and titanium alloy, and hot spinning is suitable for steel and stainless steel.
In the forming process of the helical pressure machine, many crucial points include the selection of forming parts, the choice of processing parameters, the choice of forming die and the control of process environment, which are the key points that determine the quality of processing.
DESIGN OF RACKING
The design of the racking is the basic condition of ensuring the processing accuracy and the whole structural stability of the helical pressure machine. It consists of the base, column and rack.
The base is the basic supporting part of the entire machine. The base is made of high-quality casting materials with average foundation strength. It is the bearing part of the whole machine, supporting the pressure head and ensuring the stability of the whole machine.
The column is the connection between base and grille. It usually consists of main column and secondary column or liftable main column and liftable secondary column.
The rack is the upper part of the whole machine. It consists of main rack and secondary rack or pivotable main rack and pivotable secondary rack, which are used to connect the pressure head and the column and set the pressing force and stroke.
DIE DESIGN
Die is the most important part of forming technology. The design requirements of forming die should be considered from the perspective of forming quality, manufacturing cost and processing time.
Forming method
Forming die is used to realize the shaping of one or more parts. Therefore, the forming method of helical pressure machine should be determined according to the shape and structure of the parts to be processed.
Process refinement
Process refinement means that when a forming method is selected, its method and degree of refinement should be considered from the process characteristics, pressure distribution and necessary process conditions.
Mould material selection
The material of the die should meet the requirements of the forming process and the characteristics of the parts. Usually use high-quality steel, some difficult pieces are cast iron.
Determining the size of the die
The size of the mould should be determined according to the size and shape of the parts. The mold size should be larger than the size of the parts, so as to ensure the forming quality and strength of the die.
DESIGN OF BLANKING
In order to ensure the accuracy of processing, it is necessary to use blanking when processing by helical pressure machine. The design requirements of blanking are to determine the size and shape of the blank according to the size and shape of the parts, so as to ensure its accuracy and strength.
Type of blanking
The choice of blanking type should be based on the production form of blanking and batch. In view of the parts with different structures, different types of blanking should be adopted. For example, flat blanking is suitable for parts with a large enough flat face, while round blanking is suitable for round and complex parts.
Blanking size
The blank shall be cut according to the size and shape of the parts, and the excess material shall be added at the block plane to ensure its strength. The width of excess material depends on the size and shape of the blank and the allowable clearance of the forming die.
Blanking material
The blanking material should be the same kind of material as the parts. It should also be noted that the mechanical properties of the blanking material should not be lower than the material of the parts.
PROCESSING AND MANUFACTURING
Processing generally refers to the process of cutting, heat treatment and chemical processing of metal materials. The manufacturing process of the helical pressure machine should be determined according to the purpose of its use and the characteristics of the workpiece. The surface roughness of the workpiece shall meet the requirements of the process technology, and the chemical composition test must be performed. The microstructure of the workpiece should also meet certain process requirements. In addition, the workpiece should meet the hardness and surface quality requirements listed in the process technology.
Test and inspect
Inspection and testing of parts is an important measure to ensure the quality of parts. It is a direct measure to detect product defects and eliminate hidden dangers. In general, the test and inspection of parts should include mould, dimension and surface quality test. The test and inspection of mould shall be carried out according to the drawings and process requirements, and the mould deviation shall meet the requirements of the drawings. For part dimension inspection, the measuring instrument should be calibrated regularly, and the measuring instrument and measuring tool should be used correctly. The surface quality index of the parts should meet the requirements, and any geometric defects should be avoided.
CONCLUSION
Due to the characteristics of the helical pressure machine, it can realize the processing of parts with complex shapes and medium and small batch production. The helical pressure machine has the advantages of simple structure and fast operation speed, and the advantages of low production cost and high production efficiency. In order to ensure the processing quality of the helical pressure machine, the process design and die design should pay attention to the material selection, process preparation and machining accuracy. The test and inspection of parts is also an important measure to ensure the quality of parts.
