The application of metal parts, screws, or nuts, and other accessories is mainly due to the continuous increase of mechanical equipment. You can see that the current aerospace technology, or the application of CNC equipment, the processing of mold accessories, are all assisted by mechanical equipment. The overall effect is obvious. Improving the processing speed has brought certain benefits to the manufacturers It's better to order.
Engaged in mechanical processing, high-precision mechanical parts manufacturing, blank selection, not only affects the economy of blank manufacturing, but also affects the economy of machining. Therefore, when determining the blank, we should consider not only the hot working factors, but also the economic factors, as well as the requirements of cold working, so as to reduce the manufacturing cost of parts in the process of determining the blank.
1. Casting: parts with complex shape should be manufactured by casting method. At present, most castings are cast by sand mold, which is divided into wood mold manual molding and metal mold machine modeling. It is suitable for small batch production of single piece or casting of large parts. Metal mold machine modeling productivity is high, casting accuracy is high, but the equipment cost is high, the weight of castings is also limited, suitable for mass production of small and medium castings. Secondly, a small number of small castings with high quality requirements can be made by special casting, such as pressure casting, centrifugal manufacturing and investment casting.
2. Forging: for steel parts with high mechanical strength requirements, forging blanks are generally used. There are two kinds of Forgings: free forging and die forging. Free forging forgings can be obtained by hand forging (small blank), mechanical hammer forging (medium-sized blank) or press forging (large-scale blank). This kind of forging has low precision, low productivity and large machining allowance. Moreover, the structure of the parts must be simple. It is suitable for single piece and small batch production, as well as for manufacturing large forgings.
The precision and surface quality of die forging are better than that of free forging, and the shape of forging can be more complex, so the machining allowance can be reduced. The production efficiency of die forging is much higher than that of free forging, but it needs special equipment and forging die, so it is suitable for medium and small forgings with large batch.
3. Profiles: profiles can be divided into round steel, square steel, hexagonal angle steel, flat steel, angle steel, channel steel, I-beam and other profiles with special cross-section. There are hot rolled and cold drawn profiles. Hot rolled profiles have low precision but low price, which are used for the blank of general parts; cold drawn profiles are small in size and high in precision, easy to realize automatic feeding, but with high price, they are mostly used in large batch production and suitable for automatic machine tool processing.
4. Weldment: weldment is a combination obtained by welding method. The advantages of welding are simple manufacturing, short cycle and saving materials. The disadvantages are poor vibration resistance and large deformation. Mechanical processing can only be carried out after aging treatment. Reasonable selection of the blank of mechanical manufacturing precision parts can not only save material cost, but also save a lot of processing time and improve production efficiency.