First, the characteristics of precision die forging
1. Significantly reduce the cost of product parts
Forgings have less machining allowance, small tolerances and small surface roughness. The machining of parts can be replaced in part or in whole, thus saving material and machining time and increasing labor productivity.
2. Improve the mechanical properties and service life of the product
The metal flow line of the forging is not cut, and the streamline distribution is more reasonable. The strength of the forged part is about 20% higher than the cutting process, and it has strong resistance to stress and corrosion and long service life.
3. Suitable for parts with complex shape, high performance and expensive materials
These parts, which are difficult to manufacture by mechanical processing, are expensive, expensive, and have a significant effect on precision forging, such as gears, toothed parts, blades, aerospace parts and electrical parts.
4. Have a suitable batch
Precision forging is not economical in any case, and should be considered in terms of batch, performance requirements, overall cost and economic benefits of forging products. The larger the batch, the better the benefit.
Second, the design features of forgings
The precision die forging design is the same as the ordinary die forging, and the precision forgings are drawn according to the product parts drawing. It is the main basis for formulating precision forging process, designing precision forging die, manufacturing and accepting forgings.
1. Determine the shape, size, position and various technical requirements of the precision forged part.
2. Partition surface selection: Generally, it is not allowed to be selected on the precision forging part. For example, the split surface of the straight bevel gear is usually selected on the largest diameter and the back tapered surface of the tooth profile, and the split surface of the spur gear is selected on the largest end face.
3. Machining allowance and tolerance: After forging, the precision forging part will not be machined any more, so there is no machining allowance, which is exactly the same as the part drawing size. The margin and tolerance of other processing surfaces can be determined according to the national standard GB12362-90 precision grade.
4. Drafting angle and fillet radius: When precision die forging, the die is generally provided with an ejection device, so the draft angle is small. The fillet radius is based on the part drawing.