How to choose the tolerance of precision metal stamping parts
Dimensional tolerances of formed stampings: The formed stampings are divided into 10 precision grades, represented by FT1 to ft10, where ft represents the dimensional tolerance of the formed stampings, and the Arabic numerals indicate the tolerance level. Accuracy class reduced from FT1 to FT10.
The limit deviation of stamping parts: the stamping deviation of the hole size is 0, the upper deviation is the lower deviation plus the dimensional tolerance; the upper deviation of the shaft size is the basic deviation, the value is 0, and the lower deviation is the upper deviation minus the dimensional tolerance. The upper and lower deviations of hole center distance, hole edge distance, bend, stretch length and height are half the dimensional tolerance.
Tolerance is the range of dimensional variation. The lower the value, the lower the precision and the less difficult the processing; the lower the value, the higher the precision and the more difficult the processing. So what are the important considerations in production:
1. Bending angle: the angular size of the stamping part formed by bending.
2. Blanking angle: the angle dimension formed by blanking on the plane of the flat or forming part.
3. Blanking fillet radius: the linear dimension of the fillet radius of the stamping part, the parts processed by the separation process such as stamping and blanking.
4. Forming size: the angular size formed by the bending linear dimension of the stamping part processed by stretching and other processes.
5. Blanking size: the linear size of stamping parts, used for stamping, blanking and other separation processes.