Dimensional tolerance standard for metal stamping parts

Metal stamping processing is a commonly used metal processing method in China at present. In the production process of workpiece, due to the comprehensive influence of machining accuracy of machinery and equipment, die wear, machining error and other factors, the size of metal stamping parts produced and processed is difficult to achieve absolute accuracy.

Therefore, in order to ensure the availability of the workpiece, we must control the tolerance of metal stamping parts to the minimum. So do you know the tolerance standard of metal stamping parts is implemented according to what specification?

Gb/t13914-2002 dimensional tolerances of stamping parts stipulates the dimensional tolerances of stamping parts. According to the flat stamping parts and formed stamping parts, the dimensional tolerances are specified respectively. The dimensional tolerance value of the stamping part is related to the size of the stamping part and the thickness of the plate, on the other hand, it is related to the accuracy grade.

Dimensional tolerance of flat stamping parts: it is divided into 11 grades, which are represented by ST1 to st11. Among them, St represents the dimensional tolerance of flat stamping parts, and the tolerance grade code is represented by Arabic numerals. The accuracy level decreases from ST1 to st11.

Dimensional tolerance of formed stampings: formed stampings are divided into 10 accuracy levels, which are expressed by FT1 to ft10. Among them, FT represents dimensional tolerance of formed stampings, and Arabic numerals represent tolerance levels. The accuracy level decreases from FT1 to ft10.

Limit deviation of stamping parts: the press deviation of hole size is 0, and the upper deviation is the lower deviation plus dimensional tolerance; The upper deviation of the shaft dimension is the basic deviation, and the value is 0. The lower deviation is the upper deviation minus the dimensional tolerance. For hole center distance, hole edge distance, bending, drawing length, height and other upper and lower deviations are specified as half of the dimensional tolerance.

Tolerance is the range of dimension change. The larger its value is, the lower its accuracy is, and the less difficult it is to process. The smaller its value is, the higher its accuracy is, and the greater its processing difficulty is.