The machining accuracy of zippers refers to the degree to which the actual values of parameters such as size, shape, and mutual position of the parts are close to their ideal values after processing. The closer the actual value is to the ideal value, i.e. the smaller the machining error, the higher the machining accuracy.

The machining accuracy of zipper mechanical parts includes dimensional accuracy, shape accuracy, and positional accuracy.

1. Shape accuracy refers to the degree to which the actual shape of a part is close to its ideal shape. There are six types of shape tolerances: straightness, flatness, roundness, cylindricity, line profile, and surface profile.

2. Dimensional accuracy refers to the degree to which the actual size of a part is close to the ideal size, commonly represented by dimensional tolerance. According to the national standard GB/T 1800 According to the regulations from 1 to 2009, standard tolerances are divided into 20 levels, namely ITOI, ITO, IT! To IT18, IT represents standard tolerances, and Arabic numerals represent tolerance levels. The larger the number, the greater the tolerance value, and the lower the dimensional accuracy. IT01- IT13 is used for fitting dimensions, and currently the commonly used tolerance for fitting dimensions is below IT5; IT14-IT18 is used for non fit sizes.

3. Position tolerance refers to the degree to which the actual position between the surface, axis, or symmetrical plane of a part is close to the ideal position. There are eight types of positional tolerances: parallelism, verticality, inclination, positional tolerance, coaxiality, symmetry, national runout, and total runout. Usually, the accuracy achieved by a certain processing method refers to the accuracy that can be achieved under normal operating conditions, known as economic accuracy. When designing parts, the first step is to determine which level of accuracy to choose based on the importance of part size, and secondly, to consider the equipment conditions and processing costs of the factory.