The processing of metal stamping parts is a commonly used metal processing method in China at present. In the process of workpiece production, due to the comprehensive influence of various factors, such as machining accuracy of machinery and equipment, die wear, machining error and so on, the size of metal stamping parts produced by production is difficult to be accurate.
Therefore, in order to ensure the availability of the workpiece, the tolerance of metal stamping parts must be controlled to a minimum.
So do you know what the tolerance standard for metal stamping parts is based on?
Dimensional tolerances for stamping parts are specified in GB/T13914-2002 dimensional tolerances.
The dimensional tolerances are specified respectively according to the flat stamping parts and the formed stamping parts.
The dimensional tolerance of stamping parts is related to the size and thickness of stamping parts, and to the grade of accuracy on the other hand.
Dimensional tolerances of flat stamping parts: divided into 11 grades, expressed by ST1 to ST11, in which ST represents the dimensional tolerance of flat stamping parts, and the tolerance grade code is indicated by Arabic numerals.
From ST1 to ST11, the precision level decreases in turn.
Dimensional tolerances for forming stamping parts: forming stamping parts are divided into 10 accuracy levels, which are expressed by FT1 to FT10, where FT represents the dimensional tolerance of forming stamping parts and Arabic numerals indicate the tolerance level.
From FT1 to FT10, the precision level decreases in turn.
Limit deviation of stamping parts: the hole size is 0 according to the lower deviation, the upper deviation is the lower deviation plus dimensional tolerance; the shaft size specifies the upper deviation as the basic deviation, the value is 0, and the lower deviation is the upper deviation minus the dimensional tolerance.
The upper and lower deviations such as hole center distance, hole edge distance, length and height of bending and drawing are specified as half of the dimensional tolerance.
Tolerance is the range of dimensional variation, the larger the value, the lower the precision, and the less the difficulty of machining. The smaller the value, the higher the precision and the greater the difficulty of machining.