Annotation of parts drawing of precision parts processing

When processing precision parts, first of all, the part drawing is an indispensable part. A clearly marked, reasonable, complete and clear part drawing has an important basis for the production and inspection of the workpiece. It is one of the important contents of the part drawing and is the drawing. The most prescriptive part. So what are the labeling methods and features of the part drawing? The following is a summary of some experience of the programmers of the parts processing plant.

     1. Limit deviation annotation method:

     This kind of labeling method is often seen in the actual production drawings of precision parts processing plants. When the deviation is not zero, the positive and negative signs must be marked. There are five points to be noted in the labeling:

    (1) When the upper or lower deviation is zero, it should be marked with the number "0" and be aligned with the single digit before the decimal point of the lower or upper deviation.

    (2) The upper deviation should be noted on the upper right of the basic size, and the lower deviation should be noted on the same bottom line of the basic size.

    (3) The decimal points of the upper and lower deviations must be aligned, and the number of digits after the decimal point must be the same

    (4) Zeros that do not work after the decimal point may not be written, except when it is necessary to use zeros to make up for the same number of digits after the decimal point.

    (5) When the upper and lower deviation values are the same, the deviation only needs to be noted once, and the symbol "±" should be marked between the deviation and the basic size, and make it the same height as the number.

      2. Mark the tolerance zone code

      This labeling method generally uses special measuring tools (such as plug gauge, ring gauge, etc.) to meet the needs of mass production, so there is no need to mark the deviation value.

      3. Mark tolerance code and limit deviation at the same time

      This labeling method is generally applicable to the situation of unstable production in precision parts processing factories. It is convenient for the inspection of general measuring tools even if it is used for special measuring tools. This is the limit deviation. Parentheses should be added.